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Nguyen KQT, Nguyen HH, Phung HTT, Chung KL, Vu TY. A close-up shot of protein-protein docking, from experiment to theory and reverse with the PROTAC performers. J Biomol Struct Dyn 2024:1-8. [PMID: 38284361 DOI: 10.1080/07391102.2024.2308778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 01/14/2024] [Indexed: 01/30/2024]
Abstract
PROTACs (Proteolysis Targeting Chimeras), heterobifunctional molecules, exhibit selectivity in degrading target proteins through E3 ubiquitin ligases. Designing effective PROTACs requires a deep understanding of the intricate binding interactions in the ternary complex (POI/PROTAC/E3 ligase), crucial for efficient target protein degradation. To address this challenge, we introduce a novel computational virtual screening method that considers essential amino acid interactions between the protein of interest and the chosen E3 ligase. This approach enhances accuracy and reliability, facilitating the strategic development of potent PROTACs. Utilizing a crystallized model of the VHL:PROTAC:SMARCA2BD ternary complex (PDB: 7Z6L), we assessed the effectiveness of our method. Our study reveals that increasing the number of essential restraints between the two proteins reduces the generated docking poses, leading to closer alignment with the experimental ternary complex. Specifically, utilizing three restraints showed the closest resemblance to the published complex, highlighting crucial interactions such as an H-bond between A:Gln 89 and B:Asn 67, along with two hydrophobic interactions: A:Gly 22 with B:Arg 69 and A:Glu 37 with B:Pro 99. This resulted in a significant decrease in the mean RMSD value from 31.8 and 31.0 Å to 24.4 Å, respectively. This underscores the importance of incorporating multiple essential restraints to enhance docking accuracy. Building on this progress, we introduce a systematic approach to design potential PROTACs between the Estrogen receptor and the E3 ligase, utilizing bridging intermediates with 4, 6, or 7 carbon atoms. By providing a more accurate and efficient means of identifying optimal PROTAC candidates, this approach has the potential to accelerate the development of targeted therapies and reduce the time and costs associated with drug discovery.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Hieu Hien Nguyen
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Huong Thi Thu Phung
- NTT Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam
| | - Khanh Linh Chung
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Thien Y Vu
- Faculty of Pharmacy, Ton Duc Thang University, Ho Chi Minh City, Vietnam
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2
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Hirvasniemi J, Runhaar J, van der Heijden RA, Zokaeinikoo M, Yang M, Li X, Tan J, Rajamohan HR, Zhou Y, Deniz CM, Caliva F, Iriondo C, Lee JJ, Liu F, Martinez AM, Namiri N, Pedoia V, Panfilov E, Bayramoglu N, Nguyen HH, Nieminen MT, Saarakkala S, Tiulpin A, Lin E, Li A, Li V, Dam EB, Chaudhari AS, Kijowski R, Bierma-Zeinstra S, Oei EHG, Klein S. The KNee OsteoArthritis Prediction (KNOAP2020) challenge: An image analysis challenge to predict incident symptomatic radiographic knee osteoarthritis from MRI and X-ray images. Osteoarthritis Cartilage 2023; 31:115-125. [PMID: 36243308 DOI: 10.1016/j.joca.2022.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 09/02/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
OBJECTIVES The KNee OsteoArthritis Prediction (KNOAP2020) challenge was organized to objectively compare methods for the prediction of incident symptomatic radiographic knee osteoarthritis within 78 months on a test set with blinded ground truth. DESIGN The challenge participants were free to use any available data sources to train their models. A test set of 423 knees from the Prevention of Knee Osteoarthritis in Overweight Females (PROOF) study consisting of magnetic resonance imaging (MRI) and X-ray image data along with clinical risk factors at baseline was made available to all challenge participants. The ground truth outcomes, i.e., which knees developed incident symptomatic radiographic knee osteoarthritis (according to the combined ACR criteria) within 78 months, were not provided to the participants. To assess the performance of the submitted models, we used the area under the receiver operating characteristic curve (ROCAUC) and balanced accuracy (BACC). RESULTS Seven teams submitted 23 entries in total. A majority of the algorithms were trained on data from the Osteoarthritis Initiative. The model with the highest ROCAUC (0.64 (95% confidence interval (CI): 0.57-0.70)) used deep learning to extract information from X-ray images combined with clinical variables. The model with the highest BACC (0.59 (95% CI: 0.52-0.65)) ensembled three different models that used automatically extracted X-ray and MRI features along with clinical variables. CONCLUSION The KNOAP2020 challenge established a benchmark for predicting incident symptomatic radiographic knee osteoarthritis. Accurate prediction of incident symptomatic radiographic knee osteoarthritis is a complex and still unsolved problem requiring additional investigation.
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Affiliation(s)
- J Hirvasniemi
- Department of Radiology & Nuclear Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands.
| | - J Runhaar
- Department of General Practice, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - R A van der Heijden
- Department of Radiology & Nuclear Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - M Zokaeinikoo
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, USA
| | - M Yang
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, USA
| | - X Li
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, USA
| | - J Tan
- Department of Radiology, New York University Langone Health, New York, USA
| | - H R Rajamohan
- Department of Radiology, New York University Langone Health, New York, USA
| | - Y Zhou
- Department of Radiology, New York University Langone Health, New York, USA
| | - C M Deniz
- Department of Radiology, New York University Langone Health, New York, USA
| | - F Caliva
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - C Iriondo
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - J J Lee
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - F Liu
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - A M Martinez
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - N Namiri
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - V Pedoia
- Department of Radiology, University of California, San Francisco, San Francisco, USA
| | - E Panfilov
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - N Bayramoglu
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - H H Nguyen
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - M T Nieminen
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - S Saarakkala
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
| | - A Tiulpin
- Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - E Lin
- Akousist Co., Ltd., Taoyuan City, Taiwan
| | - A Li
- Akousist Co., Ltd., Taoyuan City, Taiwan
| | - V Li
- Akousist Co., Ltd., Taoyuan City, Taiwan
| | - E B Dam
- Department of Computer Science, University of Copenhagen, Copenhagen, Denmark
| | - A S Chaudhari
- Department of Radiology, Stanford University, Stanford, USA
| | - R Kijowski
- Department of Radiology, New York University Langone Health, New York, USA
| | - S Bierma-Zeinstra
- Department of General Practice, Erasmus MC University Medical Center, Rotterdam, the Netherlands; Department of Orthopedics & Sport Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - E H G Oei
- Department of Radiology & Nuclear Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - S Klein
- Department of Radiology & Nuclear Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
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Frolkis A, Borman M, Sadler MD, Congly SE, Nguyen HH, Lee S, Stinton L, Swain M, Coffin CS, Aspinall A, Burak KW, Shaheen AM. A202 IMPACT OF THE COVID-19 PANDEMIC ON THE EPIDEMIOLOGY OF ALCOHOL-RELATED HEPATITIS. J Can Assoc Gastroenterol 2022. [PMCID: PMC9383486 DOI: 10.1093/jcag/gwab049.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Alcohol-related hepatitis (AH) is the most severe form of alcohol-related liver disease, with rising incidence. Stay-at-home orders for the COVID-19 pandemic were associated with increased alcohol consumption. Online sales reported a 262% increase from March 2019 to 2020. Aims The purpose of this study was to track the epidemiology of hospitalizations for AH by sex before and after the COVID-19 pandemic. We hypothesized that AH would be more severe in females and younger individuals during the pandemic. Methods Using the Discharge Abstract Database, we identified all hospitalizations in Alberta with international classification of disease-10 codes for AH between March 2018 and September 2020. We merged this dataset with provincial laboratory data to identify all inpatient lab values. We calculated Model for End-Stage Liver Disease (MELD) and Maddrey scores and validated a laboratory-based algorithm for AH. Severe AH was defined as Maddrey score > 32. Onset of the pandemic was defined as March 2020. Stratified by pandemic onset, descriptive statistics were done with Chi-squared and Kruskal Wallis tests. Inpatient mortality was assessed as a primary outcome. Binomial regression was used to assess changes in frequency of admission for AH with the denominator as all cirrhosis-related admissions over the same time-period. Results We identified 991 hospitalizations for AH prior to the pandemic (n=381, 38.5% female) and 417 during the pandemic (n=144, 34.5% female). Hospitalizations for AH significantly increased during the pandemic (p = 0.04) (Figure 1). Median Maddrey score for females (30.5) before the pandemic was significantly higher than for males (22.9), p < 0.01. During the pandemic, median Maddrey for females (28.7) was higher than males 21.4, p = 0.07. Median age at admission was significantly lower for both males and females during the pandemic (age 44 and 41, respectively) as compared to prior (age 47 and 45, respectively) p < 0.05. There was no significant difference in MELD between sexes before (13.5 for females, 14.0 for males, p = 0.15) and during the pandemic (13.3 for females, 13.0 for males, p = 0.75). Additionally, there was no significant difference in mortality between sexes before (10.4% in females, 11.5% in males, p = 0.22) and after the pandemic (9.2% in females, 9.9% in males, p = 0.67). Conclusions Hospitalizations for AH rose during the pandemic and occurred at younger ages. There was no significant difference in disease severity or mortality before and during the pandemic. Overall, females have more severe AH than males. Public health efforts should continue to be made to educate about the harms of alcohol excess and offer community support. Future studies will expand the trend through multiple pandemic waves. ![]()
Funding Agencies None
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Affiliation(s)
- A Frolkis
- University of Calgary, Calgary, AB, Canada
| | - M Borman
- Division of Gastroenterology, University of Calgary, Calgary, AB, Canada
| | - M D Sadler
- University of Calgary, Calgary, AB, Canada
| | - S E Congly
- Liver Unit, Division of Gastroenterology, Department of Medicine, University of Calgary Cumming School of Medicine, Calgary, AB, Canada
| | - H H Nguyen
- Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | - S Lee
- University of Calgary, Calgary, AB, Canada
| | - L Stinton
- University of Calgary, Calgary, AB, Canada
| | - M Swain
- University of Calgary, Calgary, AB, Canada
| | - C S Coffin
- Medicine, University of Calgary, Calgary, AB, Canada
| | - A Aspinall
- University of Calgary, Calgary, AB, Canada
| | - K W Burak
- Liver Unit, Univ Calgary, Calgary, AB, Canada
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DeVries DR, Olafsen LJ, Olafsen JS, Nguyen HH, Schubert KE, Dayawansa S, Huang JH. Ultrasound Localization of Nitinol Wire of Sub-Wavelength Dimension. IEEE Open J Eng Med Biol 2022; 3:18-24. [PMID: 35399792 PMCID: PMC8939268 DOI: 10.1109/ojemb.2022.3151230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 01/10/2022] [Accepted: 02/09/2022] [Indexed: 11/08/2022] Open
Abstract
Goal: To enhance endovascular navigation using surgical guidewires and the use of ionizing radiation, we demonstrate a method for ultrasonic localization of wires with diameters less than the wavelength of ultrasound in the medium. Methods: Nitinol wires with diameters ranging from 50 μm to 250 μm were imaged ultrasonically in a 0.25-in-diameter water-filled tube in a gelatin medium. Imaging frequencies were 5 MHz, 7.5 MHZ, and 10 MHz. Results: For the full range of diameters traversing the phantom, the wires were localized successfully via visual inspection of both regular and difference ultrasound images. Similarly, two convolutional neural networks were trained, and both achieved an accuracy of over 95%. Conclusions: Wires with diameters as small as 50 μm were localized successfully in a water-based gelatin phantom, indicating the potential use of ultrasound to enhance endovascular navigation and surgical treatment.
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Affiliation(s)
| | | | | | | | | | - S Dayawansa
- Baylor Scott & White Health Neuroscience Institute Temple TX 76502 USA
| | - J H Huang
- Baylor Scott & White Health Neuroscience Institute Temple TX 76502 USA
- Texas A&M University College of Medicine Temple TX 76502 USA
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Nguyen HH, Wu F, Makin JK, Oddy WH, Wills K, Jones G, Winzenberg T. Associations of dietary patterns with bone density and fractures in adults: A systematic review and meta-analysis. Aust J Gen Pract 2021; 50:394-401. [PMID: 34059846 DOI: 10.31128/ajgp-02-20-5245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND OBJECTIVES Although nutrition is important to bone health, the impact of different dietary patterns on bone density and fracture is unclear. The aim of this study was to synthesise conflicting evidence from observational studies to determine associations of empirically derived dietary patterns with bone density and fracture in healthy adults. METHOD A systematic review (PROSPERO CRD42017071676) with meta-analysis where possible (for hip fracture) and otherwise with best-evidence synthesis. RESULTS Twenty-one studies were included in the best-evidence synthesis and four in the meta-analysis. Meta-analysis demonstrated a protective association between 'healthy' pattern score and hip fracture (risk ratio 0.73; 95% confidence interval: 0.56, 0.96; I2 = 95%) for highest compared to lowest 'healthy' pattern score category. In best-evidence synthesis, there was conflicting evidence for associations of both pattern scores with bone density at all sites and total fractures and for 'Western' score and hip fracture. No study reported detrimental effects of 'healthy' patterns, or beneficial effects of 'Western' patterns. DISCUSSION The results suggest that general practitioners promoting a 'healthy' dietary pattern is, at worst, unlikely to be detrimental for bone health and, at best, may reduce hip fracture.
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Affiliation(s)
- H H Nguyen
- BPH, MPH, Menzies Institute for Medical Research, University of Tasmania, Tas; Ho Chi Minh City University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam
| | - F Wu
- PhD, Research Fellow, Menzies Institute for Medical Research, University of Tasmania, Tas
| | - J K Makin
- MSc, Senior Consultant: Research and Evaluation, Menzies Institute for Medical Research, University of Tasmania, Tas
| | - W H Oddy
- MPH, PhD, Professorial Research Fellow, Menzies Institute for Medical Research, University of@Tasmania, Tas
| | - K Wills
- PhD, Research Fellow Biostatistics, Menzies Institute for Medical Research, University of Tasmania, Tas
| | - G Jones
- FRACP, MD, Professorial Research Fellow, Menzies Institute for Medical Research, University of@Tasmania, Tas
| | - T Winzenberg
- FRACGP, PhD, Professor of Chronic Disease Management, Menzies Institute for Medical Research, University of Tasmania, Tas
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Abstract
Premature ovarian insufficiency (POI), defined as a loss of ovarian function before the age of 40 years, is a life-changing diagnosis that has numerous long-term consequences. Musculoskeletal complications, including osteoporosis and fractures, are a key concern for women with POI. The risk of bone loss is influenced by the underlying etiology of POI, and the degree and duration of estrogen deficiency. A decline in muscle mass as a result of estrogen and androgen deficiency may contribute to skeletal fragility, but has not been examined in women with POI. This article aims to review musculoskeletal health in POI; summarize the traditional and novel modalities available to screen for skeletal fragility and muscle dysfunction; and provide updated evidence for available management strategies.
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Affiliation(s)
- H H Nguyen
- Department of Medicine, School of Clinical Sciences, Monash University, Clayton, VIC, Australia.,Department of Endocrinology, Monash Health, Clayton, VIC, Australia.,Department of Endocrinology and Diabetes, Western Health, St. Albans, VIC, Australia
| | - F Milat
- Department of Medicine, School of Clinical Sciences, Monash University, Clayton, VIC, Australia.,Department of Endocrinology, Monash Health, Clayton, VIC, Australia.,Metabolic Bone Research Group, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - A J Vincent
- Department of Endocrinology, Monash Health, Clayton, VIC, Australia.,Monash Centre for Health Research and Implementation, Monash University, Clayton, VIC, Australia
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Nguyen HH, Khathlan A, Fritzler MJ, Swain M. A185 IMPACT OF HEPATITIS C ERADICATION USING DIRECT ACTING ANTIVIRALS ON CONCURRENT PRIMARY BILIARY CHOLANGITIS AND ASSOCIATED AUTOIMMUNITY. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- H H Nguyen
- Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | - A Khathlan
- Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | - M J Fritzler
- Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | - M Swain
- Univ Calgary, Calgary, AB, Canada
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Nguyen HH, Shaheen AM, Urbanski S, Fritzler MJ, Mason AL, Swain M. A194 CAN NOVEL SEROLOGICAL MARKERS BE USED TO BETTER DEFINE PRIMARY BILIARY CHOLANGITIS (PBC)-AUTOIMMUNE HEPATITIS (AIH) OVERLAP SYNDROME. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- H H Nguyen
- Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | | | - S Urbanski
- University of Calgary, Calgary, AB, Canada
| | | | - A L Mason
- University of Alberta, Edmonton, AB, Canada
| | - M Swain
- Univ Calgary, Calgary, AB, Canada
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Saul D, Gleitz S, Nguyen HH, Kosinsky RL, Sehmisch S, Hoffmann DB, Wassmann M, Menger B, Komrakova M. Effect of the lipoxygenase-inhibitors baicalein and zileuton on the vertebra in ovariectomized rats. Bone 2017; 101:134-144. [PMID: 28455215 DOI: 10.1016/j.bone.2017.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 04/13/2017] [Accepted: 04/19/2017] [Indexed: 12/25/2022]
Abstract
Osteoporosis is one of the most common diseases worldwide. In osteoporosis, vertebral fractures represent a major burden. Lipoxygenase (LOX) inhibitors such as baicalein and zileuton may represent a promising therapeutic option owing to their antioxidative effects and suppression of various inflammatory processes in muscle and bone. The effect of these LOX inhibitors on the spine was studied in osteopenic rats. Female Sprague-Dawley rats were divided two times into five groups: four groups each were ovariectomized (OVX) and one control group was non-ovariectomized (NON-OVX). Eight weeks after ovariectomy, three concentrations of baicalein (1mg/kg body weight [BW], 10mg/kgBW, and 100mg/kgBW) were administered subcutaneously daily in three OVX groups for 4weeks. Similarly, zileuton was administered in three concentrations via food for 5weeks. In vivo computed tomography (pQCT) of the spine was performed before the treatments and at the end of the experiment. Lumbar vertebrae were subjected to a compression test, micro-CT, and ashing analyses. After baicalein treatment, cortical bone mineral density (BMD) was improved; trabecular connectivity and trabecular BMD were diminished at high dose. After zileuton treatment, the total BMD, anorganic weight, trabecular nodes, and trabecular area were improved. The in vivo stress-strain index was increased and alkaline phosphatase activity in serum was enhanced after both treatments. A dose-dependent effect was not clearly observed after both treatments. The treatments using baicalein for 4 and zileuton for 5weeks were not sufficient to change the biomechanical properties and bone volume fraction (BV/TV). Overall, baicalein improved the cortical bone parameters whereas zileuton had a favorable effect on the trabecular structure. Moreover, both treatments increased the bone formation rate. Longer trials, a combination of both LOX inhibitors, and their effect at the cellular and molecular levels should be investigated in further studies.
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Affiliation(s)
- D Saul
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany.
| | - S Gleitz
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - H H Nguyen
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - R L Kosinsky
- Department of General, Visceral and Pediatric Surgery, University Medical Center Goettingen, 37075 Goettingen, Germany
| | - S Sehmisch
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - D B Hoffmann
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - M Wassmann
- Medical Institute of General Hygiene and Environmental Health, University of Goettingen, 37075 Goettingen, Germany
| | - B Menger
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - M Komrakova
- Department of Trauma, Orthopaedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
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Nguyen LA, Do DH, Nguyen LT, Do NT, Nguyen HH, Nguyen VT, Vu DQ, Nguyen HT, Kato M, Jordan MR, Bui DD. A13 HIV drug resistance over a decade of antiretroviral therapy scale-up for HIV/AIDS patients in Vietnam. Virus Evol 2017; 3:vew036.012. [PMID: 28845273 PMCID: PMC5565985 DOI: 10.1093/ve/vew036.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- L A Nguyen
- National Institute of Hygiene and Epidemiology, Vietnam
| | - D H Do
- National Institute of Hygiene and Epidemiology, Vietnam
| | - L T Nguyen
- National Institute of Hygiene and Epidemiology, Vietnam
| | - N T Do
- Vietnam Authority for HIV AIDS Control
| | | | | | - D Q Vu
- Hanoi Medical University, Vietnam
| | - H T Nguyen
- National Institute of Hygiene and Epidemiology, Vietnam
| | - M Kato
- World Health Organization, Vietnam
| | - M R Jordan
- Tuffs University School of Medicine, Massachusetts, USA
| | - D D Bui
- Vietnam Authority for HIV AIDS Control
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Nguyen HH, El Ezzi M, Mingotaud C, Destarac M, Marty JD, Lauth-de Viguerie N. Doubly thermo-responsive copolymers in ionic liquid. Soft Matter 2016; 12:3246-3251. [PMID: 26931173 DOI: 10.1039/c5sm03063c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the behaviour of thermoresponsive block copolymers of n-butyl acrylate and N-alkyl acrylamides in [C2mim][NTf2]. Poly(N-isopropylacrylamide) exhibits an upper critical solution temperature in [C2mim][NTf2] whereas poly(n-butyl acrylate) has a lower critical solution temperature. Consequently, these polymers exhibit double thermo-responsiveness correlated with the macromolecular structure. Moreover, a switching from micellar to reverse micellar structures was induced by a change in temperature. This property enables the development of reversible shuttles between ionic liquids and water.
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Affiliation(s)
- H H Nguyen
- IMRCP, University of Toulouse, CNRS UMR 5623, 31062 Toulouse, France.
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Teller S, Nguyen HH, Walther R. PDX-1 interagiert mit 14-3-3epsilon in pankreatischen Betazellen. DIABETOL STOFFWECHS 2007. [DOI: 10.1055/s-2007-982171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Knorr B, Franchi LM, Bisgaard H, Vermeulen JH, LeSouef P, Santanello N, Michele TM, Reiss TF, Nguyen HH, Bratton DL. Montelukast, a leukotriene receptor antagonist, for the treatment of persistent asthma in children aged 2 to 5 years. Pediatrics 2001; 108:E48. [PMID: 11533366 DOI: 10.1542/peds.108.3.e48] [Citation(s) in RCA: 261] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The greatest prevalence of asthma is in preschool children; however, the clinical utility of asthma therapy for this age group is limited by a narrow therapeutic index, long-term tolerability, and frequency and/or difficulty of administration. Inhaled corticosteroids and inhaled cromolyn are the most commonly prescribed controller therapies for young children with persistent asthma, although very young patients may have difficulty using inhalers, and dose delivery can be variable. Moreover, reduced compliance with inhaled therapy relative to orally administered therapy has been reported. One potential advantage of montelukast is the ease of administering a once-daily chewable tablet; additionally, no tachyphylaxis or change in the safety profile has been evidenced after up to 140 and 80 weeks of montelukast therapy in adults and pediatric patients aged 6 to 14 years, respectively. To our knowledge, this represents the first large, multicenter study to address the effects of a leukotriene receptor antagonist in children younger than 5 years of age with persistent asthma, as well as one of the few asthma studies that incorporated end points validated for use in preschool children. OBJECTIVE Our primary objective was to determine the safety profile of montelukast, an oral leukotriene receptor antagonist, in preschool children with persistent asthma. Secondarily, the effect of montelukast on exploratory measures of asthma control was also studied. DESIGN AND STATISTICAL ANALYSIS: We conducted a double-blind, multicenter, multinational study at 93 centers worldwide: including 56 in the United States, and 21 in countries in Africa, Australia, Europe, North America, and South America. In this study, we randomly assigned 689 patients (aged 2-5 years) to 12 weeks of treatment with placebo (228 patients) or 4 mg of montelukast as a chewable tablet (461 patients) after a 2-week placebo baseline period. Patients had a history of physician-diagnosed asthma requiring use of beta-agonist and a predefined level of daytime asthma symptoms. Caregivers answered questions twice daily on a validated, asthma-specific diary card and, at specified times during the study, completed a validated asthma-specific quality-of-life questionnaire. Physicians and caregivers completed a global evaluation of asthma control at the end of the study. Efficacy end points included: daytime and overnight asthma symptoms, daily use of beta-agonist, days without asthma, frequency of asthma attacks, number of patients discontinued because of asthma, need for rescue medication, physician and caregiver global evaluations of change, asthma-specific caregiver quality of life, and peripheral blood eosinophil counts. Although exploratory, the efficacy end points were predefined and their analyses were written in a data analysis plan before study unblinding. At screening and at study completion, a complete physical examination was performed. Routine laboratory tests were drawn at screening and weeks 6 and 12, and submitted to a central laboratory for analysis. Adverse effects were collected from caregivers at each clinic visit. An intention-to-treat approach, including all patients with a baseline measurement and at least 1 postrandomization measurement, was performed for all efficacy end points. An analysis-of-variance model with terms for treatment, study center and stratum (inhaled/nebulized corticosteroid use, cromolyn use, or none) was used to estimate treatment group means and between-group differences and to construct 95% confidence intervals. Treatment-by-age, -sex, -race, -radioallergosorbent test, -stratum, and -study center interactions were evaluated by including each term separately. Fisher's exact test was used for between-group comparisons of the frequency of asthma attacks, discontinuations from the study because of worsening asthma, need for rescue medication, and the frequencies of adverse effects. Because of an imbalance in baseline values for eosinophil counts for the 2 treatment groups, an analysis of covariance was performed on the eosinophil change from baseline with the patient's baseline as covariate. STUDY PARTICIPANTS Of the 689 patients enrolled, approximately 60% were boys and 60% were white. Patients were relatively evenly divided by age: 21%, 24%, 30%, and 23% were aged 2, 3, 4, and 5 years, respectively. For 77% of the patients, asthma symptoms first developed during the first 3 years of life. During the placebo baseline period, patients had asthma symptoms on 6.1 days/week and used beta-agonist on 6.0 days/week. RESULTS In over 12 weeks of treatment of patients aged 2 to 5 years, montelukast administered as a 4-mg chewable tablet produced significant improvements compared with placebo in multiple parameters of asthma control including: daytime asthma symptoms (cough, wheeze, trouble breathing, and activity limitation); overnight asthma symptoms (cough); the percentage of days with asthma symptoms; the percentage of days without asthma; the need for beta-agonist or oral corticosteroids; physician global evaluations; and peripheral blood eosinophils. The clinical benefit of montelukast was evident within 1 day of starting therapy. Improvements in asthma control were consistent across age, sex, race, and study center, and whether or not patients had a positive radioallergosorbent test. Montelukast demonstrated a consistent effect regardless of concomitant use of inhaled/nebulized corticosteroid or cromolyn therapy. Caregiver global evaluations, the percentage of patients experiencing asthma attacks, and improvements in quality-of-life scores favored montelukast, but were not significantly different from placebo. There were no clinically meaningful differences between treatment groups in overall frequency of adverse effects or of individual adverse effects, with the exception of asthma, which occurred significantly more frequently in the placebo group. There were no significant differences between treatment groups in the frequency of laboratory adverse effects or in the frequency of elevated serum transaminase levels. Approximately 90% of the patients completed the study. CONCLUSIONS Oral montelukast (4-mg chewable tablet) administered once daily is effective therapy for asthma in children aged 2 to 5 years and is generally well tolerated without clinically important adverse effects. Similarly, in adults and children aged 6 to 14 years, montelukast improves multiple parameters of asthma control. Thus, this study confirms and extends the benefit of montelukast to younger children with persistent asthma.
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Affiliation(s)
- B Knorr
- Departments of Pulmonary-Immunology, Epidemiology, and Biostatistics, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
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Ge J, Perlstein DL, Nguyen HH, Bar G, Griffin RG, Stubbe J. Why multiple small subunits (Y2 and Y4) for yeast ribonucleotide reductase? Toward understanding the role of Y4. Proc Natl Acad Sci U S A 2001; 98:10067-72. [PMID: 11526232 PMCID: PMC56916 DOI: 10.1073/pnas.181336498] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides. Class I RNRs are composed of two homodimeric subunits: R1 and R2. R1 is directly involved in the reduction, and R2 contains the diferric-tyrosyl radical (Y*) cofactor essential for the initiation of reduction. Saccharomyces cerevisiae has two RNRs; Y1 and Y3 correspond to R1, whereas Y2 and Y4 correspond to R2. Y4 is essential for diferric-Y* formation in Y2 from apoY2, Fe(2+), and O(2). The actual function of Y4 is controversial. Y2 and Y4 have been further characterized in an effort to understand their respective roles in nucleotide reduction. (His)(6)-Y2, Y4, and (His)(6)-Y4 are homodimers, isolated largely in apo form. Their CD spectra reveal that they are predominantly helical. The concentrations of Y2 and Y4 in vivo are 0.5-2.3 microM, as determined by Western analysis. Incubation of Y2 and Y4 under physiological conditions generates apo Y2Y4 heterodimer, which can form a diferric-Y small middle dot when incubated with Fe(2+) and O(2). Holo Y2Y4 heterodimer contains 0.6-0.8 Y* and has a specific activity of 0.8-1.3 micromol.min.mg. Titration of Y2 with Y4 in the presence of Fe(2+) and O(2) gives maximal activity with one equivalent of Y4 per Y2. Models for the function of Y4 based on these data and the accompanying structure will be discussed.
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Affiliation(s)
- J Ge
- Department of Chemistry, Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Reinges MH, Krings T, Nguyen HH, Hans FJ, Korinth MC, Höller M, Küker W, Thiex R, Spetzger U, Gilsbach JM. Is the head position during preoperative image data acquisition essential for the accuracy of navigated brain tumor surgery? Comput Aided Surg 2001; 5:426-32. [PMID: 11295855 DOI: 10.1002/igs.1004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To analyze the influence of head positioning during preoperative image data acquisition on intraoperative accuracy of modern neuronavigation systems. MATERIAL AND METHODS All measurements were performed preoperatively before opening the head. In 24 patients, preoperative MR image data acquisition was performed twice on a 0.5 T scanner using a contrast-enhanced T1-weighted sequence; first in the neutral head position, and thereafter in the surgical head position for pterional craniotomy. For both data sets, the Sylvian fissure, the central sulcus, and the superior and inferior temporal sulci were depicted on the patient's scalp using the frameless neuronavigation system EasyGuide Neurotrade mark. At the beginning of surgery, with the head fixed in a Mayfield clamp and an articulated instrument holder being used for fixation of the navigation system's pointer, the distances of 10 correlating points of the sulci for the two data sets were measured. To evaluate the accuracy of the navigation system in this experimental set-up, a phantom study was also performed. RESULTS The phantom study revealed a mean inaccuracy of 1.6 mm (range 0.1-2.3 mm, standard deviation 0.6 mm). The patient study revealed a mean inaccuracy of 1.8 mm (range 0.4-2.8 mm, standard deviation 0.5 mm). CONCLUSIONS The data suggest that the positioning of the patient's head during preoperative imaging plays no relevant role in intraoperative accuracy of neuronavigation. However, further studies and a larger number of patients with various pathologies in different regions of the brain are necessary to obtain a better understanding of the problem of brain shift in neuronavigation due to patient positioning alone, and to avoid procedure-related operative morbidity.
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Affiliation(s)
- M H Reinges
- Department of Neurosurgery, University of Technology (RWTH), Aachen, Germany.
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Wilson WR, Siegel RS, Harisiadis LA, Davis DO, Nguyen HH, Bank WO. High-dose intra-arterial cisplatin therapy followed by radiation therapy for advanced squamous cell carcinoma of the head and neck. Arch Otolaryngol Head Neck Surg 2001; 127:809-12. [PMID: 11448355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
OBJECTIVE To assess the effectiveness of a protocol consisting of 4 cycles of high-dose intra-arterial cisplatin infusions followed by radiation therapy for improving chemotherapy response rates, organ preservation, and survival in patients with advanced-stage untreated and previously treated squamous cell carcinoma of the head and neck. DESIGN AND SETTING A prospective study of sequentially enrolled patients treated in an academic medical center. The Kaplan-Meier method was used for survival analysis. PATIENTS Fifty-eight nonpregnant adults, 18 years of age or older, with measurable untreated or recurrent advanced biopsy-proven squamous cell carcinoma of the head and neck. MAIN OUTCOME MEASURES Response rate to targeted intra-arterial cisplatin infusions, organ preservation, and survival. RESULTS Fifty-eight patients (44 men and 14 women) were followed up for at least 2 years (median duration of follow-up, 27 months). Twenty-nine (67%) of the 43 previously untreated patients had a complete response to intra-arterial cisplatin therapy. Of the untreated patients, 28 are alive and disease free after a median follow-up time of 30 months. Five of the patients with recurrent disease had a complete response to intra-arterial cisplatin therapy. There were 4 survivors after a median follow-up time of 17.5 months. Of note, there were no deaths or serious complications related to the treatment in either group. CONCLUSIONS High-dose intra-arterial cisplatin therapy provides a high complete and partial response rate (91%). The combination of high-dose intra-arterial cisplatin and radiation therapy is effective in improving survival and organ preservation rates in patients with previously untreated, advanced squamous cell carcinoma of the head and neck. This treatment protocol is much less effective for recurrent disease.
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Affiliation(s)
- W R Wilson
- Division of Hematology and Oncology, George Washington University Medical Center, 2150 Pennsylvania Ave, NW, Suite 3-428, Washington, DC 20037, USA
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Knorr B, Nguyen HH, Kearns GL, Villaran C, Boza ML, Reiss TF, Rogers JD, Zhang J, Larson P, Spielberg S. Montelukast dose selection in children ages 2 to 5 years: comparison of population pharmacokinetics between children and adults. J Clin Pharmacol 2001; 41:612-9. [PMID: 11402629 DOI: 10.1177/00912700122010492] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Montelukast, a leukotriene receptor antagonist, has demonstrated efficacy and tolerability in the treatment of asthma in patients age 6 years and older. The purpose of this open, one-period, multicenter population pharmacokinetic study was to identify a chewable tablet (CT) dose of montelukast for administration to children ages 2 to 5 years with asthma, yielding a single-dose pharmacokinetic profile (area under the plasma concentration-time curve [AUC]) comparable to that of the 10 mg film-coated tablet (FCT) dose in adults. Because patient numbers were small and the volume of blood that could be collected from individual 2- to 5-year-old patients was limited, a population pharmacokinetic approach was used to estimate population AUC (AUCpop). The 4 mg CT dose of montelukast was well tolerated and yielded an AUCpop (2721 ng.h/mL) similar to that of the adult AUCpop (2595 ng.h/mL) observed after a 10 mg FCT dose. These results support the selection of a 4 mg once-daily CT dose of montelukast for future efficacy and safety studies in children ages 2 to 5 years with asthma.
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Affiliation(s)
- B Knorr
- Merck Research Laboratories, P.O. Box 2000, RY33-656, Rahway, NJ 07065, USA
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Bar G, Bennati M, Nguyen HH, Ge J, Stubbe JA, Griffin RG. High-frequency (140-GHz) time domain EPR and ENDOR spectroscopy: the tyrosyl radical-diiron cofactor in ribonucleotide reductase from yeast. J Am Chem Soc 2001; 123:3569-76. [PMID: 11472128 DOI: 10.1021/ja003108n] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-frequency pulsed EPR and ENDOR have been employed to characterize the tyrosyl radical (Y*)-diiron cofactor in the Y2-containing R2 subunit of ribonucleotide reductase (RNR) from yeast. The present work represents the first use of 140-GHz time domain EPR and ENDOR to examine this system and demonstrates the capabilities of the method to elucidate the electronic structure and the chemical environment of protein radicals. Low-temperature spin-echo-detected EPR spectra of yeast Y* reveal an EPR line shape typical of a tyrosyl radical; however, when compared with the EPR spectra of Y* from E. coli RNR, a substantial upfield shift of the g(1)-value is observed. The origin of the shift in g(1) was investigated by 140-GHz (1)H and (2)H pulsed ENDOR experiments of the Y2-containing subunit in protonated and D(2)O-exchanged buffer. (2)H ENDOR spectra and simulations provide unambiguous evidence for one strongly coupled (2)H arising from a bond between the radical and an exchangeable proton of an adjacent residue or a water molecule. Orientation-selective 140-GHz ENDOR spectra indicate the direction of the hydrogen bond with respect to the molecular symmetry axes and the bond length (1.81 A). Finally, we have performed saturation recovery experiments and observed enhanced spin lattice relaxation rates of the Y* above 10 K. At temperatures higher than 20 K, the relaxation rates are isotropic across the EPR line, a phenomenon that we attribute to isotropic exchange interaction between Y* and the first excited paramagnetic state of the diiron cluster adjacent to it. From the activation energy of the rates, we determine the exchange interaction between the two irons of the cluster, J(exc) = -85 cm(-)(1). The relaxation mechanism and the presence of the hydrogen bond are discussed in terms of the differences in the structure of the Y*-diiron cofactor in yeast Y2 and other class I R2s.
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Affiliation(s)
- G Bar
- Center for Magnetic Resonance, Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
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Reinges MH, Krings T, Nguyen HH, Küker W, Spetzger U, Rohde V, Hütter BO, Thron A, Gilsbach JM. Virtual pointer projection of the central sulcus to the outside of the skull using frameless neuronavigation -- accuracy and applications. Acta Neurochir (Wien) 2001; 142:1385-9; discussion 1389-90. [PMID: 11214633 DOI: 10.1007/s007010070009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The purpose of this prospective study was to localize the central sulcus by frameless neuronavigation and to project this anatomical structure to the outside of the skull on the skin. This method was analyzed in respect to its practicability, accuracy, and potential applications. METHOD In 27 patients investigated (28 unaffected hemispheres), the central sulcus was virtually projected to the outside of the skull using frameless neuronavigation and a virtual pointer elongation of 15 or 20 mm. The following parameters were measured on the scalp: 1. the distance between the bregma and the midline junction of the central sulcus, and 2. the angle between the central sulcus and the midline. These dada were compared with measurements based on the original axial MR images of these patients. Finally, a laboratory phantom study was designed in analogy to a patient's examination for estimation of the overall accuracy of the neuronavigation system in the experimental setup used in this study. FINDINGS Virtual pointer projection of the central sulcus to the outside of the skull using frameless neuronavigation was found to be easily possible. The distance between the bregma and the midline junction of the central sulcus amounted to a mean of 55 mm on the left and 56 mm on the right. The angle between the central sulcus and the midline reached a mean of 63 degrees on the left and 60 degrees on the right. These data confirmed results of other studies with no frameless neuronavigation devices. The phantom study revealed a mean overall inaccuracy of 0.9 mm at a virtual pointer elongation of 15 mm. At a virtual pointer elongation of 20 mm, the mean overall inaccuracy of our study was 1.1 mm. These results correspond to the inaccuracy of frame based stereotaxy. INTERPRETATION It is easily possible, valid, and reliable to virtually project the central sulcus to the outside of the skull with an acceptably low inaccuracy using frameless neuronavigation. This is important for research studies that correlate and integrate different functional imaging methods with the aid of frameless neuronavigation.
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Affiliation(s)
- M H Reinges
- Department of Neurosurgery, Aachen University of Technology (RWTH), Germany
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21
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Nguyen HH, Vu HL, McGhee JR, Mestecky J. Heterosubtypic immunity to influenza A virus infection requires B cells but not CD8+ cytotoxic T lymphocytes. J Infect Dis 2001; 183:368-76. [PMID: 11133367 DOI: 10.1086/318084] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2000] [Revised: 10/18/2000] [Indexed: 11/03/2022] Open
Abstract
Heterosubtypic immunity (HSI), defined as protective cross-reactivity to lethal infection with influenza A virus of a serotype different from the virus initially encountered, is thought to be mediated by cross-reactive cytotoxic T lymphocytes (CTL). This study provides direct evidence for the role of effector CTL versus B cells in HSI in mice with a targeted disruption in the alpha chain of CD8 molecule (CD8(+) T cell deficient) or the immunoglobulin mu heavy chain (B cell deficient), respectively. CD8(+) T cell-deficient mice developed complete HSI. These mice displayed normal humoral immune responses, as determined by titers of subtype cross-reactive antibodies and virus-neutralizing antibodies specific for the immunizing influenza strain. In contrast, HSI was not observed in B cell-deficient mice, although these mice could mount cross-reactive CTL responses. These results show that B cells are required for HSI and provide new insight into the mechanisms of HSI, with significant implications in vaccine development.
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Affiliation(s)
- H H Nguyen
- Department of Microbiology and Immunobiology Vaccine Center, University of Alabama at Birmingham, Birmingham, AL 35294-2170, USA.
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Knorr B, Holland S, Rogers JD, Nguyen HH, Reiss TF. Montelukast adult (10-mg film-coated tablet) and pediatric (5-mg chewable tablet) dose selections. J Allergy Clin Immunol 2000; 106:S171-8. [PMID: 10984399 DOI: 10.1067/mai.2000.109424] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Montelukast is a selective leukotriene receptor antagonist that has been shown to be effective in the treatment of chronic asthma. It is approved in more than 70 countries for patients 6 years of age and older. For adults (> or = 15 years of age), a 10-mg film-coated tablet (FCT) is available, and for children (aged 6 to 14 years), a 5-mg chewable tablet (CT) is available. The adult montelukast dose (10-mg FCT) was selected on the basis of classic dose-ranging studies as the lowest dose that produces maximal improvement in both measures of airway function and patient-reported outcomes in chronic asthma and in the attenuation of exercise-induced bronchoconstriction. The strategy used for the pediatric dose selection for montelukast was based on the determination of a CT dose that would provide an overall systemic exposure to montelukast in children similar to that in adults who receive a 10-mg FCT dose. Because montelukast was to be given chronically for the treatment of asthma, the area under the plasma concentration-time curve was considered to be the pharmacokinetic measurement that best represented systemic exposure to the drug. A 5-mg CT yielded a comparable single-dose area under the plasma concentration-time curve profile to that of the adult 10-mg FCT dose and, therefore, was selected as the pediatric dose for children aged 6 to 14 years with asthma. Subsequently, 2 studies of efficacy and tolerability validated the choice of the 5-mg CT dose.
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Affiliation(s)
- B Knorr
- Department of Pulmonary-Immunology, Merck Research Laboratories, Rahway, NJ 07065, USA
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Nguyen HH, van Ginkel FW, Vu HL, Novak MJ, McGhee JR, Mestecky J. Gamma interferon is not required for mucosal cytotoxic T-lymphocyte responses or heterosubtypic immunity to influenza A virus infection in mice. J Virol 2000; 74:5495-501. [PMID: 10823854 PMCID: PMC112034 DOI: 10.1128/jvi.74.12.5495-5501.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Heterosubtypic immunity (HSI) is defined as cross-protection against influenza virus of a different serotype than the virus initially encountered and is thought to be mediated by influenza virus-specific cytotoxic T lymphocytes (CTL). Since gamma interferon (IFN-gamma) stimulates cytotoxic cells, including antigen-specific CTL which may control virus replication by secretion of antiviral cytokines such as tumor necrosis factor alpha and IFN-gamma, we have investigated the mechanism of HSI by analyzing the role of IFN-gamma for HSI in IFN-gamma gene-deleted (IFN-gamma(-/-)) mice. It has been reported that IFN-gamma is not required for recovery from primary infection with influenza virus but is important for HSI. Here, we conclusively show that IFN-gamma is not required for induction of secondary influenza virus-specific CTL responses in mediastinal lymph nodes and HSI to lethal influenza A virus infection. Although T helper 2 (Th2)-type cytokines were upregulated in the lungs of IFN-gamma(-/-) mice after virus challenge, either Th1- or Th2-biased responses could provide heterosubtypic protection. Furthermore, titers of serum-neutralizing and cross-reactive antibodies to conserved nucleoprotein in IFN-gamma(-/-) mice did not differ significantly from those in immunocompetent mice. These results indicate that lack of IFN-gamma does not impair cross-reactive virus-specific immune responses and HSI to lethal infection with influenza virus. Our findings provide new insight for the mechanisms of HSI and should be valuable in the development of protective mucosal vaccines against variant virus strains, such as influenza and human immunodeficiency virus.
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Affiliation(s)
- H H Nguyen
- Department of Microbiology and The Immunobiology Vaccine Center, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
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Vu HL, Troubetzkoy S, Nguyen HH, Russell MW, Mestecky J. A method for quantification of absolute amounts of nucleic acids by (RT)-PCR and a new mathematical model for data analysis. Nucleic Acids Res 2000; 28:E18. [PMID: 10710435 PMCID: PMC102801 DOI: 10.1093/nar/28.7.e18] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Accurate quantification of nucleic acids by competitive (RT)-PCR requires a valid internal standard, a reference for data normalization and an adequate mathematical model for data analysis. We report here an effective procedure for the generation of homologous RNA internal standards and a strategy for synthesizing and using a reference target RNA in quantification of absolute amounts of nucleic acids. Further, a new mathematical model describing the general kinetic features of competitive PCR was developed. The model extends the validity of quantitative competitive (RT)-PCR beyond the exponential phase. The new method eliminates the errors arising from different amplification efficiencies of the co-amplified sequences and from heteroduplex formation in the system. The high accuracy (relative error <2%) is comparable to the recently developed real time detection 5'-nuclease PCR. Also, corresponding computer software has been devised for practical data analysis.
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Affiliation(s)
- H L Vu
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294-2170, USA.
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Abstract
The mucosal immune system consists of molecules, cells, and organized lymphoid structures intended to provide immunity to pathogens that impinge upon mucosal surfaces. Mucosal infection by intracellular pathogens results in the induction of cell- mediated immunity, as manifested by CD4-positive (CD4 + ) T helper-type 1 cells, as well as CD8 + cytotoxic T-lymphocytes. These responses are normally accompanied by the synthesis of secretory immunoglobulin A (S-IgA) antibodies, which provide an important first line of defense against invasion of deeper tissues by these pathogens. New-generation live, attenuated viral vaccines, such as the cold-adapted, recombinant nasal influenza and oral rotavirus vaccines, optimize this form of mucosal immune protection. Despite these advances, new and reemerging infectious diseases are tipping the balance in favor of the parasite; continued mucosal vaccine development will be needed to effectively combat these new threats.
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Affiliation(s)
- F W van Ginkel
- Department of Microbiology, University of Alabama at Birmingham, 35294, USA.
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Nguyen HH, Ge J, Perlstein DL, Stubbe J. Purification of ribonucleotide reductase subunits Y1, Y2, Y3, and Y4 from yeast: Y4 plays a key role in diiron cluster assembly. Proc Natl Acad Sci U S A 1999; 96:12339-44. [PMID: 10535923 PMCID: PMC22918 DOI: 10.1073/pnas.96.22.12339] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides. Class I RNRs are composed of two types of subunits: RNR1 contains the active site for reduction and the binding sites for the nucleotide allosteric effectors. RNR2 contains the diiron-tyrosyl radical (Y.) cofactor essential for the reduction process. Studies in yeast have recently identified four RNR subunits: Y1 and Y3, Y2 and Y4. These proteins have been expressed in Saccharomyces cerevisiae and in Escherichia coli and purified to approximately 90% homogeneity. The specific activity of Y1 isolated from yeast and E. coli is 0.03 micromol.min(-1).mg(-1) and of (His)(6)-Y2 [(His)(6)-Y2-K387N] from yeast is 0.037 micromol. min(-1).mg(-1) (0.125 micromol.min(-1).mg(-1)). Y2, Y3, and Y4 isolated from E. coli have no measurable activity. Efforts to generate Y. in Y2 or Y4 using Fe(2+), O(2), and reductant have been unsuccessful. However, preliminary studies show that incubation of Y4 and Fe(2+) with inactive E. coli Y2 followed by addition of O(2) generates Y2 with a specific activity of 0.069 micromol.min(-1). mg(-1) and a Y. A similar experiment with (His)(6)-Y2-K387N, Y4, O(2), and Fe(2+) results in an increase in its specific activity to 0.30 micromol.min(-1).mg(-1). Studies with antibodies to Y4 and Y2 reveal that they can form a complex in vivo. Y4 appears to play an important role in diiron-Y. assembly of Y2.
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Affiliation(s)
- H H Nguyen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Knorr B, Larson P, Nguyen HH, Holland S, Reiss TF, Chervinsky P, Blake K, van Nispen CH, Noonan G, Freeman A, Haesen R, Michiels N, Rogers JD, Amin RD, Zhao J, Xu X, Seidenberg BC, Gertz BJ, Spielberg S. Montelukast dose selection in 6- to 14-year-olds: comparison of single-dose pharmacokinetics in children and adults. J Clin Pharmacol 1999; 39:786-93. [PMID: 10434229 DOI: 10.1177/00912709922008434] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Montelukast, an oral leukotriene-receptor antagonist, has demonstrated efficacy and tolerability for the treatment of chronic asthma in adults. A once-daily 10 mg dose (film-coated tablet) was selected as the optimal adult dose based on dose-ranging studies. Asthma is a similar disease and is treated with the same medications in children and adults. These observations suggested that a dose of montelukast in children providing overall drug exposure (i.e., montelukast plasma concentrations) similar to that of the 10 mg film-coated tablet dose in adults would be efficacious, well tolerated, and obviate the need for separate dose-ranging studies in children. Therefore, the dose of montelukast for 6- to 14-year-old children was selected by identifying the chewable tablet dose of montelukast yielding a single-dose area under the plasma concentration-time curve (AUC) comparable to that achieved with the adult 10 mg film-coated tablet dose. Based on this approach, which included dose normalization of data from several pediatric pharmacokinetic studies, a 5 mg chewable tablet dose of montelukast was selected for use in clinical efficacy studies in 6- to 14-year-old children with asthma.
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Affiliation(s)
- B Knorr
- Merck Research Laboratories, Rahway, NJ 07065, USA
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28
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Nguyen HH, Proye CA, Carnaille B, Combemale F, Pattou FN, Huglo D. Tumour size: the only predictive factor for 131I MIBG uptake in phaeochromocytoma and paraganglioma. Aust N Z J Surg 1999; 69:350-3. [PMID: 10353549 DOI: 10.1046/j.1440-1622.1999.01570.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND 131I Meta-iodobenzylguanidine (131I MIBG) scintigraphy can detect chromaffin tumours with a high specificity but its sensitivity remains limited. In this study, the influence of clinical features and tumour pathology on the results of 131I MIBG of patients with phaeochromocytomas and paragangliomas was examined. METHODS The records of 104 patients operated on for chromaffin tumours who had pre-operative 131I MIBG were reviewed. Demographic data, clinical features, biochemical results and pathology of tumours were analysed. The size of the tumour was assessed by the three measured diameters of the specimen and its calculated volume. Univariate relationship between tumours' characteristics and the results of 131I MIBG were examined. RESULTS Out of 119 tumours, 104 (87%) were detected by 131I MIBG. Mean +/- SD largest diameter and volume of the tumours were 6.0 +/- 2.4 cm (range 0.8-11.5 cm) and 68 +/- 74 cm3 (range 0.2-421 cm3). Results of 131I MIBG were significantly correlated with both the largest diameter of the tumour (P < 0.01) and by its volume (P < 0.001). 131I MIBG was negative in 35.5% of tumours < 20 cm3 and in 2.6% of those < 20 cm3. No other criteria were correlated with positive 131I MIBG, including aetiology, pathology or catecholamine secretion pattern. CONCLUSIONS The result of 131I MIBG scanning in patients with chromaffin tumours is significantly correlated with the size of the tumour.
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Affiliation(s)
- H H Nguyen
- Department of General and Endocrine Surgery, Hôpital Claude-Huriez, Lille, France
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29
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Abstract
Multiple endocrine neoplasia is an uncommon but fascinating condition. In this review we examine the multifaceted presentations, the diagnostic challenges and different management strategies for various syndromes. This is an attempt to share our knowledge and experience towards achieving better outcomes in the management of the diseases.
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Affiliation(s)
- C A Proye
- Department of General and Endocrine Surgery, Hopital Claude Huriez, Lille, France
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30
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Nguyen HH, Moldoveanu Z, Novak MJ, van Ginkel FW, Ban E, Kiyono H, McGhee JR, Mestecky J. Heterosubtypic immunity to lethal influenza A virus infection is associated with virus-specific CD8(+) cytotoxic T lymphocyte responses induced in mucosa-associated tissues. Virology 1999; 254:50-60. [PMID: 9927573 DOI: 10.1006/viro.1998.9521] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heterosubtypic immunity, defined as cross-reactive immune responses to influenza virus of a different serotype than the virus initially encountered, was investigated in association with virus-specific cytotoxic T lymphocyte (CTL) responses induced in systemic and mucosa-associated lymph nodes after immunization via different routes. Mice immunized by the pulmonary route with live nonpathogenic influenza virus, strain Udorn (H3N2), survived challenge with mouse-adapted pathogenic influenza virus, strain PR/8/34 (H1N1). These mice developed strong heterosubtypic CTL responses in spleen, cervical lymph nodes (CLN), and mediastinal lymph nodes (MLN). Alternately, only 20% of mice immunized intravenously, intraperitoneally, or intranasally survived the challenge; all of these developed CTL responses in spleen and CLN, but not in MLN. Direct correlation between short-term and long-term memory heterosubtypic CTL responses induced in MLN and host recovery after lethal infection indicates that these CTL responses may play an important role in heterosubtypic immunity. Furthermore, induction and maintenance of memory CTL in regional mucosa-associated lymphoid tissues are highly dependent on mucosal immunization. The results implicate the mechanism of heterosubtypic immunity and should be an important consideration in the development of protective mucosal vaccines against variant strains of influenza and HIV.
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Affiliation(s)
- H H Nguyen
- Department of Microbiology and The Immunobiology Vaccine Center, University of Alabama at Birmingham, Birmingham, Alabama, 35294-2170, USA
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31
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Kemp JP, Dockhorn RJ, Shapiro GG, Nguyen HH, Reiss TF, Seidenberg BC, Knorr B. Montelukast once daily inhibits exercise-induced bronchoconstriction in 6- to 14-year-old children with asthma. J Pediatr 1998; 133:424-8. [PMID: 9738728 DOI: 10.1016/s0022-3476(98)70281-1] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine whether montelukast, a leukotriene receptor antagonist, attenuates exercise-induced bronchoconstriction (EIB) in 6- to 14-year-old children with asthma. STUDY DESIGN Double-blind, multicenter, 2-period crossover study. Children (n = 27) with forced expiratory volume in 1 second (FEV1) > or =70% of the predicted value and a fall in FEV1 > or =20% after exercise on 2 occasions. Patients received montelukast (5-mg chewable tablet) or placebo once daily in the evening for 2 days in crossover fashion (at least 4 days between treatment periods). Standardized exercise challenges were performed 20 to 24 hours after the last dose in each period. End points included area above the postexercise percent fall in FEV1 versus time curve (AAC0-60 min), maximum percent fall in FEV1 from pre-exercise baseline, and time to recovery of FEV1 to within 5% of pre-exercise baseline. RESULTS Montelukast significantly reduced AAC0-60 min (265 vs 590% x min for montelukast and placebo, respectively, P < or = .05; approximately 59% protection relative to placebo) and the maximum percent fall (18% vs 26% for montelukast and placebo, respectively, P < or = .05). Montelukast treatment resulted in a shorter time to recovery (18 vs 28 minutes for montelukast and placebo, respectively, P = .079). CONCLUSIONS Montelukast attenuates EIB at the end of the dosing interval in 6- to 14-year-old children with asthma.
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Affiliation(s)
- J P Kemp
- Allergy and Asthma Medical Group and Research Center, San Diego, California, USA
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32
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Nguyen HH, Boyaka PN, Moldoveanu Z, Novak MJ, Kiyono H, McGhee JR, Mestecky J. Influenza virus-infected epithelial cells present viral antigens to antigen-specific CD8+ cytotoxic T lymphocytes. J Virol 1998; 72:4534-6. [PMID: 9557755 PMCID: PMC109702 DOI: 10.1128/jvi.72.5.4534-4536.1998] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We have investigated the mechanisms involved in the clearance of viral infection at the epithelium level by analyzing the activity of influenza virus-specific cytotoxic T lymphocytes (CTL) against virus-infected CMT-93 intestinal epithelial cells. Epithelial cells infected with live influenza virus effectively present viral antigens and were lysed by both homotypic and heterotypic influenza virus-specific CD8+ T cells. These results shed new light on the control of viral infection through the elimination of virus-infected epithelial cells by virus-specific CTL and demonstrate that CMT-93 cells furnish an appropriate model for in vitro evaluation of CTL activity against virus-infected epithelial cells.
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Affiliation(s)
- H H Nguyen
- Department of Microbiology and The Immunobiology Vaccine Center, University of Alabama at Birmingham, 35294-2170, USA.
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33
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Nguyen HH, Elliott SJ, Yip JH, Chan SI. The particulate methane monooxygenase from methylococcus capsulatus (Bath) is a novel copper-containing three-subunit enzyme. Isolation and characterization. J Biol Chem 1998; 273:7957-66. [PMID: 9525893 DOI: 10.1074/jbc.273.14.7957] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The particulate methane monooxygenase (pMMO) is known to be very difficult to study mainly due to its unusual activity instability in vitro. By cultivating Methylococcus capsulatus (Bath) under methane stress conditions and high copper levels in the growth medium, membranes highly enriched in the pMMO with exceptionally stable activity can be isolated from these cells. Purified and active pMMO can be subsequently obtained from these membrane preparations using protocols in which an excess of reductants and anaerobic conditions were maintained during membrane solubilization by dodecyl beta-D-maltoside and purification by chromatography. The pMMO was found to be the major constituent in these membranes, constituting 60-80% of total membrane proteins. The dominant species of the pMMO was found to consist of three subunits, alpha, beta, and gamma, with an apparent molecular mass of 45, 26, and 23 kDa, respectively. A second species of the pMMO, a proteolytically processed version of the enzyme, was found to be composed of three subunits, alpha', beta, and gamma, with an apparent molecular mass of 35, 26, and 23 kDa, respectively. The alpha and alpha' subunits from these two forms of the pMMO contain identical N-terminal sequences. The gamma subunit, however, exhibits variation in its N-terminal sequence. The pMMO is a copper-containing protein only and shows a requirement for Cu(I) ions. Approximately 12-15 Cu ions per 94-kDa monomeric unit were observed. The pMMO is sensitive to dioxygen tension. On the basis of dioxygen sensitivity, three kinetically distinct forms of the enzyme can be distinguished. A slow but air-stable form, which is converted into a "pulsed" state upon direct exposure to atmospheric oxygen pressure, is considered as type I pMMO. This form was the subject of our pMMO isolation effort. Other forms (types II and III) are deactivated to various extents upon exposure to atmospheric dioxygen pressure. Under inactivating conditions, these unstable forms release protons to the buffer (approximately 10 H+/94-kDa monomeric unit) and eventually become completely inactive.
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Affiliation(s)
- H H Nguyen
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, USA
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34
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Abstract
Intranasal (i.n.) immunization is a very effective route for inducing mucosal immunity, but the cellular mechanism responsible for regulating and disseminating these responses is not fully understood. The authors studied the role of nasal lymphoid tissue (NALT) as a mucosal inductive site by using highly purified NALT cells obtained by a new method of mechanical isolation. The NALT cells, like Peyer's patch (PP) cells, were smaller in size and less granular than lymphocytes from salivary glands (SG) and small intestinal lamina propria (LP). The NALT cells isolated from i.n. immunized mice contained antigen-specific antibody-secreting cells (ASC) predominantly of immunoglobulin (Ig)A isotype, similar to those also recovered from salivary glands in a time course study. However, the higher proportion of smaller sized sports formed by NALT cells in ELISPOT assays suggested that these cells were less differentiated precursors of those found in salivary glands. This was supported by the fact that after i.n. immunization, IgA ASC appeared in NALT, as well as in mucosal effector sites SG and LP, but none or very few in another mucosal inductive site, PP. In contrast, after intragastric (i.g.) immunization, IgA ASC were detected in PP, along with the SG and LP, but none or very few in NALT. Furthermore, after i.n. immunization, lymphocytes from NALT but not PP proliferated in response to the specific antigen in culture. These findings imply that NALT served as an inductive site for IgA antibody responses at mucosal effector sites.
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Affiliation(s)
- H Y Wu
- Department of Microbiology, University of Alabama at Birmingham 35294, USA
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35
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Chen CH, Cartwright J, Li Z, Lou S, Nguyen HH, Gotto AM, Henry PD. Inhibitory effects of hypercholesterolemia and ox-LDL on angiogenesis-like endothelial growth in rabbit aortic explants. Essential role of basic fibroblast growth factor. Arterioscler Thromb Vasc Biol 1997; 17:1303-12. [PMID: 9261260 DOI: 10.1161/01.atv.17.7.1303] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hypercholesterolemic (HC) rabbits exhibit suppressed compensatory vascular growth after restriction of arterial supply. However, neovascularization is commonly found in atheromas containing inflammatory cells. We used an in vitro model to determine the effects of hypercholesterolemia on angiogenesis in the absence or presence of inflammatory cells. HC rabbit aortic explants (1 mm2) with or without (n = 90 each) lesion-forming inflammatory cells were cultured in a collagen matrix with serum-free medium. Explant-derived endothelial cell growth was organized into capillary-like microtubes (CLM) that could be videomicroscopically quantified. CLM growth from lesion-free HC explants was significantly reduced to 13 +/- 4% of the value in explants (n = 90) from normocholesterolemic (NC, n = 15) rabbits (P < .001). In contrast, in lesion-containing HC explants, the matrix was invaded by foam cells, and CLM growth was not inhibited. Immunoassayable basic fibroblast growth factor (bFGF, in pg/mL) in the culture medium was significantly lower in lesion-free HC (< 5) than NC explants (11 +/- 2, P < .01) or HC explants with lesions (14 +/- 3). In addition, CLM growth was reduced in NC explants incubated with oxidized LDL (ox-LDL, 50-100 micrograms/mL). Exogenous bFGF (10 ng/mL) reversed the inhibitory effects of hypercholesterolemia and ox-LDL, whereas bFGF-neutralizing antibody (10 micrograms/mL) abolished CLM growth in all groups. In cultured rabbit aortic endothelial cells, ox-LDL reduced DNA synthesis, but this inhibition was reversed by bFGF. We conclude that hypercholesterolemia and ox-LDL inhibit angiogenesis like endothelial growth because of a suppressed availability of endogenous bFGF. Retained responsiveness to exogenous bFGF suggests that inducing bFGF expression at targeted sites may improve collateral growth in hyperlipidemic arterial disease.
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Affiliation(s)
- C H Chen
- Department of Medicine, Baylor College of Medicine, Houston, Tex. 77030, USA.
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36
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Qiu WW, Stucker FJ, Nguyen HH, Yin SS. Effects of brain stem lesions on cochlear function: mechanism of hearing improvement after removal of a brain stem tumor. Otolaryngol Head Neck Surg 1996; 115:560-7. [PMID: 8969763 DOI: 10.1016/s0194-5998(96)70012-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
EOAEs are well correlated with changes of hearing sensitivity during the clinical course of brain stem lesions, as shown in this case study. They may serve as sensitive indicators to evaluate the possible effects of a brain stem lesion on cochlear function and monitor the attempted preservation of hearing during CPA or brain stem surgeries. It is thereby suggested that EOAEs should be included in an audiologic test battery in a differential diagnosis of retrocochlear lesions.
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Affiliation(s)
- W W Qiu
- Department of Otolaryngology-Head Neck Surgery, Louisiana State University Medical Center in Shreveport 71130-3932, USA
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37
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Abstract
This study was designed to quantitatively characterize the time course of facial palsy and the relationship between electroneurography and the facial nerve grading percentage as a function of onset time. Bilateral electroneurographic recordings during different stages in the course of the disease were repeated and compared with categorized videotaped facial movements using the House-Brackmann facial nerve grading system in 32 patients with Bell palsy. Preliminary results of this study demonstrate a time gap between the percentage of electroneurographic response and the category of the facial nerve grading system during the same period of disease progress. A theoretical model of the time course and specific patterns regarding the recovery of facial function is established. The theoretical time course of facial palsy is divided into 3 stages; preclinical, clinical, and postclinical. Based on the time course of electroneurographic and facial grading functions, the period between 10 and 14 days after onset was found to be most valuable for prediction of recovery. According to this theoretical model, a given time course pattern based on the results of serial electroneurographic recordings provides reliable prognostic information on recovery from Bell palsy.
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Affiliation(s)
- W W Qiu
- Department of Otolaryngology-Head and Neck Surgery, Louisiana State University Medical Center, Shreveport, USA
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38
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Castany MA, Nguyen HH, Pospísil M, Fric P, Tlaskalová-Hogenová H. Natural killer cell activity in coeliac disease: effect of in vitro treatment on effector lymphocytes and/or target lymphoblastoid, myeloid and epithelial cell lines with gliadin. Folia Microbiol (Praha) 1995; 40:615-20. [PMID: 8768253 DOI: 10.1007/bf02818518] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To analyze the possible involvement of natural killer (NK) cell activity in the pathogenetic mechanism of coeliac disease (CD) we measured the spontaneous cytotoxic cell activity of peripheral blood mononuclear cells (PMNC) from patients with CD and from healthy donors. No significant differences were found between the NK cell activity of PMNC from healthy donors and from patients with CD using a standard 51 Cr release assay. However, a 30-min treatment of PMNC with gliadin inhibited NK cell activity in patients with CD. On the other hand, a 1-d incubation with gliadin induced cytotoxic cell activity of PMNC against the NK-resistant target cells such as the epithelial HT-29 and the lymphoblastoid RAJI cell lines, suggesting that activation of PMNC by cultivation with gliadin can occur.
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Affiliation(s)
- M A Castany
- Department of Immunology and Gnotobiology, Academy of Sciences of the Czech Republic
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39
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Chen CH, Nguyen HH, Weilbaecher D, Luo S, Gotto AM, Henry PD. Basic fibroblast growth factor reverses atherosclerotic impairment of human coronary angiogenesis-like responses in vitro. Atherosclerosis 1995; 116:261-8. [PMID: 7575781 DOI: 10.1016/0021-9150(95)05542-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The influence of atherosclerosis on vascular growth in humans was evaluated in an in vitro model of angiogenesis. Coronary artery intima-media explants from patients (n = 10) with coronary artery disease (CAD) (in all cases Stary type V lesions) and patients without CAD (n = 10) were cultured in a collagen matrix containing serum-free medium. Endothelial cell growth from explants was organized as capillary-like microtubes (CLM); the sum of their lengths was morphometrically quantitated as an index of angiogenesis. CLM growth was suppressed in CAD explants (n = 120), the index values at two weeks averaging only 20% +/- 3% of non-CAD explants (n = 120, P < 0.001). Addition of exogenous basic fibroblast growth factor (bFGF) (10 ng/ml) stimulated CLM growth substantially more in the CAD than in the non-CAD group, whereas bFGF-neutralizing antibodies nearly abolished growth in both. Endothelial cells isolated from non-CAD coronary arteries exhibited in culture typical endothelial characteristics, including cobblestone appearance, staining for von Willebrand factor, CLM formation on Matrigel substrate, and sensitivity to bFGF and to bFGF-neutralizing antibody. Inhibition of cell replication by oxidized low-density lipoprotein (OxLDL) was reversed by bFGF. We conclude that human atherosclerosis is associated with impairment of angiogenesis-like endothelial growth and that decreased bFGF availability contributes to the impairment.
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Affiliation(s)
- C H Chen
- Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA
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40
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Abstract
An unusual case with delayed presentation of a false popliteal aneurysm following transfemoral embolectomy is reported. It highlights that arterial embolectomy, despite its well-established merits, may have major complications.
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Affiliation(s)
- H H Nguyen
- University Department of Surgery, Repatriation General Hospital, Nedlands, Western Australia
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41
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Dallob AL, Sadick NS, Unger W, Lipert S, Geissler LA, Gregoire SL, Nguyen HH, Moore EC, Tanaka WK. The effect of finasteride, a 5 alpha-reductase inhibitor, on scalp skin testosterone and dihydrotestosterone concentrations in patients with male pattern baldness. J Clin Endocrinol Metab 1994; 79:703-6. [PMID: 8077349 DOI: 10.1210/jcem.79.3.8077349] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of the 5 alpha-reductase inhibitor, finasteride, on scalp skin testosterone (T) and dihydrotestosterone (DHT) levels were studied in patients with male pattern baldness. In a double blind study, male patients undergoing hair transplantation were treated with oral finasteride (5 mg/day) or placebo for 28 days. Scalp skin biopsies were obtained before and after treatment for measurement of T and DHT by high pressure liquid chromatography-RIA. In 10 male subjects studied at baseline, mean (+/- SEM) DHT levels were significantly higher in bald (7.37 +/- 1.24 pmol/g) compared to hair-containing (4.20 +/- 0.65 pmol/g) scalp, whereas there was no difference in mean T levels at baseline. In bald scalp from 8 patients treated with finasteride, the mean DHT concentration decreased from 6.40 +/- 1.07 pmol/g at baseline to 3.62 +/- 0.38 pmol/g on day 28. Scalp T levels increased in 6 of 8 subjects treated with finasteride. Finasteride decreased the mean serum DHT concentration from 1.36 +/- 0.18 nmol/L (n = 8) at baseline to 0.46 +/- 0.10 nmol/L on day 28 and had no effect on serum T. There were no significant changes in scalp or serum T or DHT in placebo-treated patients. In this study, male subjects treated with 5 mg/day finasteride for 4 weeks had significantly decreased concentrations of DHT in bald scalp, resulting in a mean level similar to the baseline levels found in hair-containing scalp.
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Affiliation(s)
- A L Dallob
- Merck Research Laboratories, Rahway, New Jersey 07065
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42
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Nguyen HH, Shiemke AK, Jacobs SJ, Hales BJ, Lidstrom ME, Chan SI. The nature of the copper ions in the membranes containing the particulate methane monooxygenase from Methylococcus capsulatus (Bath). J Biol Chem 1994; 269:14995-5005. [PMID: 8195135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
It is shown that the particulate methane monooxygenase (pMMO) has an obligate requirement for copper. The MMO activity in the particulate fractions obtained from Methylococcus capsulatus (Bath) cells is found to increase with increasing copper content of the membranes. The enzyme activity from membranes obtained from cells grown at low copper levels can be stimulated further by the addition of Cu(II) ions to the assay medium. The membrane-bound copper ions can exist in both Cu(II) and Cu(I) forms. EPR and magnetic susceptibility characterizations of the membranes indicate the presence of an exchange-coupled trinuclear Cu(II) cluster when the bulk of the copper ions is oxidized. However, the functional form of the enzyme is the reduced or partially reduced form. The copper ions in the membrane fractions as isolated often exhibit a high level of reduction. An EPR spectrum with one unpaired electron spin delocalized over three copper nuclei has been observed for the two-electron reduced trinuclear copper cluster. The high correlation between the copper level in the membranes and enzymatic activity as well as the high reactivity of the reduced copper clusters toward dioxygen strongly indicate that the membrane-bound copper ions constitute the active sites of the pMMO.
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Affiliation(s)
- H H Nguyen
- A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena 91125
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43
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Abstract
In multicentre clinical trials using a common protocol, the centres are usually regarded as being a fixed factor, thus allowing any treatment-by-centre interaction to be omitted from the error term for the effect of treatment. However, we feel it necessary to use the treatment-by-centre interaction as the error term if there is substantial evidence that the interaction with centres is qualitative instead of quantitative. To make allowance for the estimated uncertainties of the centre means, we propose choosing a reference value (for example, the median of the ordered array of centre means) and converting the individual centre results into standardized deviations from the reference value. The deviations are then reordered, and the results 'pushed back' by amounts appropriate for the corresponding order statistics in a sample from the relevant distribution. The pushed-back standardized deviations are then restored to the original scale. The appearance of opposite signs among the destandardized values for the various centres is then taken as 'substantial evidence' of qualitative interaction. Procedures are presented using, in any combination: (i) Gaussian, or Student's t-distribution; (ii) order-statistic medians or outward 90 per cent points of the corresponding order statistic distributions; (iii) pooling or grouping and pooling the internally estimated standard deviations of the centre means. The use of the least conservative combination--Student's t, outward 90 per cent points, grouping and pooling--is recommended.
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Affiliation(s)
- J L Ciminera
- Merck Research Laboratories, West Point, PA 19486
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44
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Abstract
Two procedures, based on proposals discussed by Mosteller and Tukey, are described for obtaining a combined estimate of the difference between two treatment means and its confidence interval from multicentre clinical trial data. Both procedures provide estimates in the possible presence of heteroscedasticity. The first procedure is designated the primary analysis for efficacy assessment. It omits treatment-by-centre interaction from the error term for treatment, unless there is substantial evidence of qualitative interaction (Ciminera et al.) or other special circumstances. The second procedure is the primary analysis whenever there is substantial evidence of qualitative interaction, and can be used whenever there are other reasons to make an analysis allowing for interaction.
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Affiliation(s)
- J L Ciminera
- Merck Research Laboratories, West Point, PA 19486
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45
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Larsen RW, Nunez DJ, MacLeod J, Shiemke AK, Musser SM, Nguyen HH, Ondrias MR, Chan SI. Spectroscopic characterization of heme A reconstituted myoglobin. J Inorg Biochem 1992; 48:21-31. [PMID: 1326598 DOI: 10.1016/0162-0134(92)80049-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The focus of this study was to examine the functional role of the unusual peripheral substitution of heme A. The effects of heme A stereochemistry on the reconstitution of the porphyrin have been examined in the heme A-apo-myoglobin complex using optical absorption and resonance Raman and electron paramagnetic resonance spectroscopies. The addition of one equivalent of heme A to apo-Mb produces a complex which displays spectroscopic signals consistent with a distribution of high- and low-spin heme chromophores. These results indicate that the incorporation of heme A into apo-Mb significantly perturbs the protein refolding.
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Affiliation(s)
- R W Larsen
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena 91125
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46
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Abstract
Unilateral vocal cord paralysis is a common finding in the practice of otolaryngology. Multiple etiologies have been described and have not changed appreciably in the last century. We attempted to characterize the contemporary evaluation of unilateral vocal cord paralysis, with consideration given to cost-effectiveness. Thirty-one board-certified otolaryngologists were interviewed to determine their typical evaluation protocol. The average cost of an evaluation totaled $1706.18, with a range of $112.56 to $3439.52. Otolaryngologists with more years of experience tended to pursue briefer and less expensive evaluations. The charts of 187 patients with a diagnosis of vocal paralysis from 1983 to 1991 were reviewed, of which 113 were evaluable. Eighty-four of these 113 (74%) were unilateral. In 48 of 84 cases (57%), the cause was apparent at the time of diagnosis. In 36 of 84 cases (43%), an evaluation was necessary. A diagnosis was achieved in 27 of these 36 instances (75%), with the most useful test being a chest roentgenogram (n = 13, 48%). The most common cause of unilateral vocal cord paralysis in our series was neoplasm (n = 34, 40%), followed by surgical trauma (n = 29, 35%). In no instance was a malignancy discovered subsequent to the initial evaluation. The most cost-efficient, inclusive diagnostic evaluation of unilateral vocal cord paralysis involves a stepwise progression through the tests that are most likely to yield a diagnosis, with endoscopy reserved for those cases in which simpler, less invasive tests have not indicated a cause.
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Affiliation(s)
- D J Terris
- Division of Otolaryngology-Head and Neck Surgery, Stanford University Medical Center, CA 94305
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47
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Abstract
Neutral metalloproteinases degrade components of the extracellular matrix, including collagen types I-V, fibronectin, laminin and proteoglycan. However, their ability to degrade intact glomerular basement membrane (GBM) has not previously been investigated. Incubation of [3H]GBM (50,000 c.p.m.; pH 7.5; 24 h at 37 degrees C) with purified gelatinase or stromelysin (2 units) resulted in significant GBM degradation: gelatinase, 46 +/- 2.2; stromelysin, 59 +/- 5.8 (means +/- S.E.M.; percentage release of non-sedimentable radioactivity; n = 4). In contrast, 2 units of collagenase released only 5.6 +/- 0.52% (n = 3) of the [3H]GBM radioactivity compared with 2.0 +/- 0.15% (n = 7) released from [3H]GBM incubated alone. Sephadex G-200 gel chromatography of supernatants obtained from incubations of [3H]GBM with either gelatinase or stromelysin confirmed the ability of these enzymes to degrade GBM and revealed both high-(800,000) and relatively low-(less than 20,000) Mr degradation products for both enzymes. GBM degradation by gelatinase and stromelysin was dose-dependent (range 0.02-2.0 units), near maximal between pH 6.0 and 8.6, and was completely inhibited (greater than 95%) by 2 mM-o-phenanthroline. Collagenase (2 units) did not enhance the degradation of GBM by either gelatinase (0.02 or 0.2 unit) or stromelysin (0.02 or 0.2 unit). Our results indicate that metalloproteinase-mediated GBM degradation by neutrophils and glomeruli may be attributable to gelatinase (neutrophils) and/or stromelysin (glomeruli) and suggest an important role for these proteinases in glomerular pathophysiology.
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Affiliation(s)
- W H Baricos
- Department of Biochemistry, Tulane Medical School, New Orleans, LA 70112
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48
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Abstract
In 12 autopsy cases of myotonic dystrophy, the most frequently observed histopathologic lesions of the cardiac conduction system were fibrosis, fatty infiltration and atrophy. Fibrosis involved the sinus node in 6 cases, atrioventricular (AV) node in 7, AV bundle in 8, bundle branches in 10 and ventricular myocardium in 11. Fatty infiltration was observed in the sinus node in two cases, AV node in two, AV bundle in six, bundle branches in one and ventricular myocardium in nine. Atrophy was prominent in the AV bundle in five and bundle branches in eight. Lymphocytes infiltrated the conduction system in three cases and were associated with myotonic dystrophy in two and varicella myocarditis in one. Ventricular myocytes were hypertrophied in seven cases, vacuolated in three and exhibited disarray in two. The distribution and extent of conduction system lesions tended to correspond to antemortem electrocardiographic abnormalities, including prolonged PR interval in six cases, intraventricular conduction delay in six and bundle branch block in four. Cardiac involvement by myotonic dystrophy may have contributed to sudden death in four cases.
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Affiliation(s)
- H H Nguyen
- Department of Pathology, Mayo Clinic, Rochester, Minnesota 55905
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49
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Abstract
Regulation of blood pressure by direct action of corticosteroids on blood vessel walls was first hypothesized in 1952 [1]. The presence of receptors specific for these hormones within the peripheral vessel walls is a pre-requisite of this hypothesis. This report documents specific binding of both aldosterone (AL) and dexamethasone (DM) in cultured human arterial smooth muscle cells. After the arterial smooth muscle cultures were incubated with tritiated AL or DM at 37 degrees C for 30-60 min, the cells were sonicated and the protein bound steroid fraction isolated on a Sephadex G25 column. Using ion exchange chromatography of this fraction, each corticosteroid receptor complex displayed a distinct, reproducible elution pattern. Aldosterone showed a single peak at 0.096 +/- 0.005 mol/l sodium phosphate and DM had two peaks at 0.029 +/- 0.003 and 0.050 +/- 0.004 mol/l sodium phosphate. The Scatchard plots of specific binding from AL saturation curves are linear and revealed mean +/- s.d. steady state binding parameters of dissociation constant (Kd) = 0.35 +/- 0.15 nmol/l and maximum binding capacity (Bmax) = 98 +/- 53 X 10(-18) mol/micrograms DNA. Similarly, the mean +/- s.d. steady state binding parameters for DM are Kd = 4.4 +/- 2.0 nmol and Bmax = 3031 +/- 1385 X 10(-18) mol/micrograms DNA. Therefore, there are approximately 1150 AL binding sites and 30000 DM binding sites per cell. The Kd and Bmax values are similar to those previously described for corticoid receptors in rat aortic smooth muscle cells and are consistent with physiological steroid concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B A Scott
- Department of Pediatrics, University of Texas Medical Branch, Galveston 77550
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50
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Nguyen HH, Baricos WH, Shah SV. Degradation of glomerular basement membrane by a neutral metalloproteinase(s) present in glomeruli isolated from normal rat kidney. Biochem Biophys Res Commun 1986; 141:898-903. [PMID: 3101682 DOI: 10.1016/s0006-291x(86)80127-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Incubation of glomerular homogenates (200 micrograms protein) with glomerular basement membrane (GBM, 30-35 micrograms hydroxyproline) at pH 7.5 for 36 h at 37 degrees C resulted in significant GBM degradation as measured by hydroxyproline release (40 +/- 6%, n = 17). GBM degradation increased with increasing incubation time (12-48 h) and glomerular protein concentration (50-250 micrograms). GBM degradation was not significantly decreased by inhibitors of serine or cysteine proteinases or the inhibitor of bacterial metalloproteinases, phosphoramidon. In contrast GBM degradation by glomerular homogenates was markedly inhibited by the metal chelators 10mM EDTA (-95 +/- 3%, n = 7) and 2mM 1,10-phenanthroline (-96 +/- 2%, n = 4). Preincubation of glomerular homogenates with trypsin (followed by soya bean trypsin inhibitor) markedly stimulated GBM degradation (+103 +/- 20%, n = 11). These results document the presence of a GBM-degrading, neutral metalloproteinase(s) in glomeruli suggesting an important role for this enzyme in glomerular pathophysiology.
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