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Lim Z, Gan S, Lim A, Lee C, Tan C. CASE REPORT: A SUCCESSFUL PREGNANCY IN AN ERA PATIENT WITH A RECEPTIVE ENDOMETRIUM AT 190±3 HOURS (DAY 8) OF PROGESTERONE. Reprod Biomed Online 2022. [DOI: 10.1016/j.rbmo.2022.08.089] [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: 11/26/2022]
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2
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Chan A, Gan S, Tan S, Lim A, Lee C. Prevalence of mosaicism in day 5 vs. day 6 human blastocysts. Reprod Biomed Online 2022. [DOI: 10.1016/j.rbmo.2022.08.028] [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: 10/07/2022]
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Akhtar D, Donaldson MA, Akhtar NH, Owen D, Gan S. A258 ROSAI-DORFMAN0-DESTOMBES DISEASE: A RARE CAUSE OF OBSTRUCTIVE JAUNDICE. J Can Assoc Gastroenterol 2022. [PMCID: PMC8859387 DOI: 10.1093/jcag/gwab049.257] [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: 11/12/2022] Open
Abstract
Background Rosai-Dorfman-Destombes Disease (RDD) is rare histiocytic disorder that is most frequently seen in children and young adults. Gastrointestinal involvement is reported in <1% of cases and typically involves the small bowel and colon. Pancreatic and hepatic involvement has been previously reported but is extremely rare. Aims To describe a case of obstructive jaundice in the setting of a very rare histiocytic disorder known as RDD. Methods Case Report Results A 59-year old previously healthy male of Asian descent presented with obstructive jaundice. Initial imaging demonstrated intra and extrahepatic biliary duct dilation with concurrent diffuse enlargement of the pancreas compatible with autoimmune pancreatitis. Endoscopic retrograde cholangiopancreatography (ERCP) was performed with stenting and biopsy. ERCP demonstrated a distal common bile duct stricture with biopsies suggestive of low grade reactive changes and inflammation. Subsequent endoscopic ultrasound (EUS) guided biopsy of the pancreas showed active and chronic inflammation, necrosis, and atrophic pancreatic tissue, with no definitive evidence of autoimmune pancreatitis (Figure 1). Ca-19-9 and IgG4 were normal. He was treated with a course of prednisone and responded well, with repeat CT imaging showing almost complete resolution of the previously demonstrated pancreatic changes. A diagnosis of autoimmune pancreatitis was made. He re-presented 6-months later, however, with fatigue and repeat imaging now displayed lymphadenopathy in the neck, chest, and abdomen, and a bulky pancreatic head with associated hepatomegaly. Lymph node excisional biopsy confirmed the diagnosis of RDD with the presence of scattered histiocytic cells showing emperipolesis with a low number of IgG4 positive cells (Figure 1). The patient was promptly initiated on prednisone and rituximab and has since then had excellent clinical response. Conclusions RDD is a rare non-Langerhans cell histiocytosis of unknown etiology that has a prevalence of 1:200 000. RDD clinically presents with painless bilateral cervical lymphadenopathy and can manifest with both nodal and extra nodal involvement. The most common sites of extra nodal disease are the skin and central nervous system, but rarely, can also present with pancreatic involvement. The use of fine needle guided biopsy in diagnosing RDD with extra nodal disease can be limited by low yield, sclerotic tissue, or non-diagnostic findings. For this reason, RDD with pancreatic involvement can masquerade as autoimmune pancreatitis, pancreatic malignancy and IgG4-related disease.This case report raises awareness about RDD with pancreatic and biliary involvement, a rare entity, that can present with obstructive jaundice. ![]()
Figure 1: Histological sections of lymph node(left) with hystiocytic cells showing emperipolesis(arrow) and pancreas(right) showing active and chronic inflamation, necrosis and atrophy Funding Agencies None
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Affiliation(s)
- D Akhtar
- Medicine, The University of British Columbia Faculty of Medicine, Vancouver, BC, Canada
| | - M A Donaldson
- The University of British Columbia Department of Medicine, Vancouver, BC, Canada
| | - N H Akhtar
- School of Medicine, University College Dublin, Dublin, Ireland
| | - D Owen
- The University of British Columbia Department of Medicine, Vancouver, BC, Canada
| | - S Gan
- Medicine, The University of British Columbia Faculty of Medicine, Vancouver, BC, Canada
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Motomura D, Gan S, Byrne M, Donnellan F. A113 ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY IN PATIENTS WITH SURGICALLY ALTERED ANATOMY IN A CANADIAN TERTIARY REFERRAL CENTRE. J Can Assoc Gastroenterol 2022. [DOI: 10.1093/jcag/gwab049.112] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Endoscopic retrograde cholangiopancreatography (ERCP) has become a mainstay of diagnosis and treatment of pancreatobiliary conditions. Surgically altered anatomy presents unique challenges in the procedure, necessitating creative solutions such as different types of endoscopes and tools. Distinct from regular anatomy, forward viewing scopes are often required for successful cannulation and therapy of the pancreaticobiliary system. To our knowledge, there is limited data on the practice of ERCP in altered anatomy in Canada.
Aims
Our aim is to present outcomes from a large series of patients with surgically altered anatomy who underwent ERCP at a large Canadian referral centre.
Methods
All ERCP procedures at a tertiary referral centre in Vancouver, Canada from Oct 2020 to Oct 2021 were reviewed retrospectively. Inclusion criteria required surgically altered anatomy and attempted ERCP. Liver transplant patients with duct-to-duct anastomosis were not included in the series. Patients with incomplete procedure documentation were excluded. Demographic, procedural and outcome data were collected. Results are presented descriptively and as median + IQR for quantitative data. Procedural success was defined as cannulation and performance of a cholangiogram and/or pancreatogram
Results
A total of 34 procedures met the inclusion criteria during the study period. Twenty-four procedures were on male patients (71%). Nineteen patients (56%) had had previous ERCP. Sixteen patients (47%) had choledocholithasis as the indication for the procedure, 9 patients (26%) had cholangitis and 5 patients (15%) had concerns of neoplasia. Some patients had multiple indications. Seventeen patients (50%) had roux-en-Y anatomy, 8 patients (24%) were post Whipple’s and 6 patients (18%) had Billroth II type anatomy. Other altered anatomy included duodenal switch, and post gastrojejunostomy bypass. The most commonly used endoscope was the adult or pediatric colonoscope (74% of cases). Single balloon enteroscope was used in 5 cases (15%). Overall success rate was 74%. The breakdown of success rate by anatomy is shown in Table 1. One (3%) complication was noted in the form of mild cholangitis, requiring only outpatient antibiotics.
Conclusions
Experience in ERCP in patients with altered anatomy is becoming more pertinent in tertiary care. Cannulation and therapy is more difficult in this cohort, but still successful in the majority of cases. Adverse events remain uncommon. Knowledge of forward viewing ERCP techniques is critical in surgically altered anatomy. Future studies will aim to expand the retrospective cohort for more quantitative analysis.
Funding Agencies
None
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Affiliation(s)
- D Motomura
- The University of British Columbia, Vancouver, BC, Canada
| | - S Gan
- Vancouver General Hospital, Vancouver, BC, Canada
| | - M Byrne
- Vancouver General Hospital, Vancouver, BC, Canada
| | - F Donnellan
- Vancouver General Hospital, Vancouver, BC, Canada
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Fetz A, Gan S. A125 SNARE TIP SPRAY COAGULATION FOR NON-CONTACT HEMOSTASIS: A SINGLE OPERATOR RETROSPECTIVE STUDY OF CLINICAL OUTCOMES. J Can Assoc Gastroenterol 2021. [DOI: 10.1093/jcag/gwab002.123] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
An emerging non-contact endoscopic method for hemostasis is the use of spray coagulation (SC) using a polypectomy snare tip. Other non-contact options, such as argon plasma coagulation (APC), can be inconvenient and costly. Our current practice includes using SC where APC would be traditionally indicated.
Aims
The aim of this study was to characterize the clinical outcomes, including rates of successful hemostasis, rebleeding, and complications, for snare tip SC in hemostasis.
Methods
We conducted a retrospective chart review of all patients who underwent therapeutic endoscopy for hemostasis using snare tip SC by a single operator at a large Canadian tertiary care centre between January 2018 and September 2020.
Results
14 patients, including 10 males and 4 females, were included. 5 (35%) patients received SC during an EGD, 5 (35%) patients during a colonoscopy, and 4 (29%) patients during a small bowel enteroscopy. Mean age was 74.4 (±11). All patients were referred for work-up of gastrointestinal bleeding or anemia. 5 (35%) patients were treated for vascular lesions including AVMs or angioectasias, 4 (29%) patients for GAVE, 3 (21%) patients for radiation proctitis, and 2 (14%) patients for bleeding ulcers. Adequate hemostasis, defined by cessation of bleeding symptoms, lack of a 10g/L or more decrease in hemoglobin post-procedure, and no further endoscopic therapies in the subsequent 28 days, was achieved in 11 patients (79%). 2 of the 3 patients in which adequate hemostasis was not achieved had additional investigations in which a second source of bleeding was found and treated. 1 patient with colonic AVMs and 1 patient with radiation proctitis required a repeat treatment in 2 weeks and 6 months, respectively. There were no incidence of prolonged abdominal pain, perforations or deaths.
Conclusions
Snare tip spray coagulation appears to be a safe and effective modality for non-contact hemostasis. Larger studies will help solidify its use in daily practice.
Funding Agencies
None
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Affiliation(s)
- A Fetz
- The University of British Columbia, Vancouver, BC, Canada
| | - S Gan
- The University of British Columbia, Vancouver, BC, Canada
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Sun Q, Liu Q, Di R, Wang Y, Gan S, Liu S, Wang X, Hu W, Cao X, Pan Z, Guo X, Yang Y, Rushdi H, Chu M. Polymorphism and Comparative Expression Analysis of THRSP Gene in Fat-Tailed and Thin-Tailed Sheep Breeds. PAK J ZOOL 2021. [DOI: 10.17582/journal.pjz/20190822070832] [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: 11/24/2022]
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Takeuchi H, Ishida T, Satou Y, Gohda J, Kitamura H, Gan S, Takahashi K, Yamaoka S. Genome-wide RNAi screen identifies MAPK-RPK required for HIV-1 proviral silencing in non-T cell reservoir cell-line model. J Virus Erad 2019. [DOI: 10.1016/s2055-6640(20)30081-9] [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: 10/23/2022] Open
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Bellinge J, Macdonald W, Gan S, Chew G, Vickery A, Lewis J, Watts G, Francis R, Schultz C. Improving Understanding of the Bone-Vascular Axis with the Use of 18F-Sodium Fluoride Positron Emission Tomography. Heart Lung Circ 2019. [DOI: 10.1016/j.hlc.2019.06.279] [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: 11/25/2022]
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Bellinge J, Macdoland W, Gan S, Chew G, Vikcery A, Lewis J, Watts G, Francis R, Schultz C. Improving Risk Stratification in Patients with Diabetes Mellitus; an 18F-Sodium Fluoride Positron Emission Tomography Study. Heart Lung Circ 2019. [DOI: 10.1016/j.hlc.2019.06.278] [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: 11/16/2022]
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Teneggi V, Ng M, Tan D, Subbiah V, Weekes C, Diermayr V, Ethirajulu K, Yeo P, Chen D, Gan S, Blanchard S, Nellore R, Lee M, Hill J, Virshup D, Madan B, Matter A. 152O A phase 1, first-in-human dose escalation study of ETC-159 in advanced or metastatic solid tumours. Ann Oncol 2016. [DOI: 10.1093/annonc/mdw579.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Teneggi V, Ng M, Tan D, Subbiah V, Weekes C, Diermayr V, Ethirajulu K, Yeo P, Chen D, Gan S, Blanchard S, Nellore R, Lee M, Hill J, Virshup D, Madan B, Matter A. 152O A phase 1, first-in-human dose escalation study of ETC-159 in advanced or metastatic solid tumours. Ann Oncol 2016. [DOI: 10.1016/s0923-7534(21)00310-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Davis S, Gan S, Jaspan D, Goldberg J. CystoSure® at Time of Hysterectomy. J Minim Invasive Gynecol 2016. [DOI: 10.1016/j.jmig.2016.08.230] [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: 11/16/2022]
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Li J, Hoeppner C, Gan S, Blair A, Min K, Sims A, Tietz A, Vinas M, Rehage T, Malhotra K, Halait H, Brophy V. An extended KRAS mutation test for the detection of 28 common mutations in FFPET and plasma specimens. Ann Oncol 2016. [DOI: 10.1093/annonc/mdw363.42] [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: 11/12/2022] Open
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Gan S, Song L, Chen W, Feng Z, Li Y, Zhang J, Zhu S. Strength and sensation after epidural ropivacaine in men and women. Anaesthesia 2015; 70:1060-5. [PMID: 25919788 DOI: 10.1111/anae.13085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2015] [Indexed: 11/30/2022]
Affiliation(s)
- S. Gan
- Department of Anaesthesiology; the First Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - L. Song
- Department of Anaesthesiology; the First Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - W. Chen
- Department of Anaesthesiology; Women's Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - Z. Feng
- Department of Anaesthesiology; the First Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - Y. Li
- Department of Anaesthesiology; Shaoxing Peoples' Hospital; Shaoxing China
| | - J. Zhang
- Department of Anaesthesiology; the First Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
| | - S. Zhu
- Department of Anaesthesiology; the First Affiliated Hospital; College of Medicine; Zhejiang University; Hangzhou China
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Ooi SQ, Chan RME, Poh LKS, Loke KY, Heng CK, Chan YH, Gan SU, Lee KO, Lee YS. Visfatin and its genetic variants are associated with obesity-related morbidities and cardiometabolic risk in severely obese children. Pediatr Obes 2014; 9:81-91. [PMID: 23447513 DOI: 10.1111/j.2047-6310.2013.00149.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [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: 06/02/2012] [Revised: 12/28/2012] [Accepted: 01/10/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND Visfatin is an adipokine, associated with obesity and possibly glucose regulation. OBJECTIVE The aim of this study was to examine the association of visfatin and its genetic variants with adiposity, cardiometabolic risk factors and obesity-related morbidities in obese children. METHODS Anthropometric measurements, dual energy X-ray absorptiometry scan, fasting blood samples and oral glucose tolerance tests were performed for 243 obese children. We screened the visfatin gene of 24 obese subjects and then performed genotyping of identified genetic variants in other 219 obese children through direct DNA sequencing. RESULTS Fasting serum visfatin correlated with measures of obesity and liver enzymes and was elevated in obese children with abnormal glucose tolerance and non-alcoholic fatty liver disease. The two upstream single nucleotide polymorphisms, -3187G>A (rs11977021) and -1537C>T (rs61330082), were at complete linkage disequilibrium. The AA genotype of -3187G>A was associated with higher serum visfatin (6.17 ± 0.76 ng mL(-1) vs. 3.92 ± 0.44 ng mL(-1)) and higher triglyceride (1.39 ± 0.08 mmol L(-1) vs. 1.19 ± 0.07 mmol L(-1)) as compared with the GG genotype. There was also a significant linear increase in serum visfatin across GG to GA to AA genotype of -3187G>A, indicating possible additive effect of A allele. The dominant GA + AA genotype model of +21426G>A (rs2302559) was associated with lower serum visfatin (3.83 ± 0.56 ng mL(-1) vs. 5.13 ± 0.34 ng mL(-1)) and lower plasma glucose (4.37 ± 0.08 mmol L(-1) vs. 4.77 ± 0.12 mmol L(-1)) as compared with the GG genotype. CONCLUSION Visfatin and its genetic variants were associated with adiposity, obesity-related morbidities and adverse cardiometabolic parameters. This supported our hypothesis that visfatin plays a significant role in the development of obesity-related morbidities and cardiometabolic risk.
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Affiliation(s)
- S Q Ooi
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Abstract
Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.
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Affiliation(s)
- KO Lee
- Department of Medicine, National University of Singapore, Singapore
| | - SU Gan
- Department of Surgery, National University of Singapore, Singapore
| | - RY Calne
- Department of Medicine and Surgery, National University of Singapore, Singapore
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Yap CL, Gan S, Ng HK. Application of vegetable oils in the treatment of polycyclic aromatic hydrocarbons-contaminated soils. J Hazard Mater 2010; 177:28-41. [PMID: 20006435 DOI: 10.1016/j.jhazmat.2009.11.078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 10/21/2009] [Accepted: 11/12/2009] [Indexed: 05/21/2023]
Abstract
A brief review is conducted on the application of vegetable oils in the treatment of PAH-contaminated soils. Three main scopes of treatment strategies are discussed in this work including soil washing by oil, integrated oil-biological treatment and integrated oil-non-biological treatment. For each of these, the arguments supporting vegetable oil application, the applied treatment techniques and their efficiencies, associated factors, as well as the feasibility of the techniques are detailed. Additionally, oil regeneration, the environmental impacts of oil residues in soil and comparison with other commonly employed techniques are also discussed.
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Affiliation(s)
- C L Yap
- Department of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia
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Gan S, Lau EV, Ng HK. Remediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs). J Hazard Mater 2009; 172:532-549. [PMID: 19700241 DOI: 10.1016/j.jhazmat.2009.07.118] [Citation(s) in RCA: 378] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 07/28/2009] [Accepted: 07/28/2009] [Indexed: 05/27/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic micropollutants which are resistant to environmental degradation due to their highly hydrophobic nature. Concerns over their adverse health effects have resulted in extensive studies on the remediation of soils contaminated with PAHs. This paper aims to provide a review of the remediation technologies specifically for PAH-contaminated soils. The technologies discussed here include solvent extraction, bioremediation, phytoremediation, chemical oxidation, photocatalytic degradation, electrokinetic remediation, thermal treatment and integrated remediation technologies. For each of these, the theories are discussed in conjunction with comparative evaluation of studies reported in the specialised literature.
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Affiliation(s)
- S Gan
- Department of Chemical and Environmental Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia.
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Swartzberg D, Dai N, Gan S, Amasino R, Granot D. Effects of cytokinin production under two SAG promoters on senescence and development of tomato plants. Plant Biol (Stuttg) 2006; 8:579-86. [PMID: 16883480 DOI: 10.1055/s-2006-924240] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Two promoters of senescence-associated ARABIDOPSIS genes, SAG12 and SAG13, were used in tomato plants to express IPT that catalyzes the rate-limiting step in cytokinin biosynthesis. Expression of these heterologous promoters in tomato plants was analyzed using the reporter gene beta-glucuronidase. Both promoters are expressed in tomato leaves in a manner similar to their expression in ARABIDOPSIS plants. The SAG12 promoter is very specific to senescing leaves, whereas the SAG13 promoter is expressed in mature leaves prior to the onset of visible senescence and its expression increases in senescing leaves. Expression of both promoters in tomato tissues other than leaves was very low . IPT expressed under the control of SAG12 and SAG13 promoters ( PSAG12::IPT and PSAG13::IPT, respectively) resulted in suppression of leaf senescence and advanced flowering, as well as in a slight increase in fruit weight and fruit total soluble solids (TSS). However, expression of PSAG13::IPT also led to stem thickening, short internodal distances and loss of apical dominance. In contrast to the autoregulation of PSAG12::IPT, PSAG13::IPT is expressed at higher levels in mature leaves. This difference is likely due to PSAG13::IPT exhibiting two phases of expression - a senescence-independent expression prior to the onset of senescence that is not subjected to autoregulation by cytokinin, and enhanced expression throughout senescence which is autoregualted by cytokinin. This moderate different autoregulated behavior of PSAG12::IPT and PSAG13::IPT markedly influenced plant development, emphasizing the biological effects of cytokinin in addition to senescence inhibition.
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Affiliation(s)
- D Swartzberg
- Institute of Plant Sciences, Agricultural Research Organization, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
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Jin E, Ma D, Liang Y, Ji A, Gan S. MRI findings of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis. Clin Radiol 2005; 60:242-50. [PMID: 15664579 DOI: 10.1016/j.crad.2004.05.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2004] [Revised: 04/26/2004] [Accepted: 05/04/2004] [Indexed: 10/25/2022]
Abstract
AIM To study the imaging characteristics of eosinophilic myelomeningoencephalitis due to Angiostrongylus cantonensis using magnetic resonance imaging (MRI). MATERIALS AND METHODS Seventeen MRI examinations of the brain and spinal cord in five patients with angiostrongyliasis cantonensis of the central nervous system were performed. The final diagnosis was based on typical clinical symptoms, results of blood and cerebrospinal fluid (CSF) tests, and the presence of nematode larvae in the CSF. The sequential MRI follow-up examinations were carried out at a different stage for every patient from 1 to 28 weeks after the onset of symptoms. The features of the lesions in the brain, spinal cord, meninges and nerve roots on MRI were studied, moreover, the development of the lesions was analysed on follow-up MRI. RESULTS Abnormalities were demonstrated on MRI in all five cases. They included three cases of meningoencephalitis, one case of encephalitis and one myelomeningitis. The locations and appearances of the lesions were as follows: (1) brain involvement in four cases (including cerebrum in four, cerebellum in two and brain stem in three), and spinal cord involvement in one case. These lesions were diffuse or scattered and appeared as similar or slightly reduced signal intensity on T1-weighted images (T1WI), high signal intensity on T2-weighted images (T2WI) and turbo fluid attenuated inversion recovery pulse sequence (FLAIR) images. After administration of gadolinium chelate (Gd-DTPA), multiple round or oval enhancing nodules, with diameters ranging from 3 to 10 mm, were seen on T1WI, a few lesions appeared as stick-shaped enhancement whose longest measurement was 14 mm. Diffuse or local oedema around the lesion could be seen. (2) Meningeal involvement in four cases, a case of ependymal involvement and a case of nerve root involvement were among them. These lesions appeared as linear or nodular enhancement of the leptomeninges and ependyma, as well as nerve root enhancement. (3) There was a mild ventricular enlargement in two cases. On follow-up MRI lesions were most severe from the 5th week to the 8th week and it took at least 4-8 weeks (1-2 months) for a lesion to resolve completely, the resolution of larger lesion needed more than 22 weeks. CONCLUSION Multiple enhancing nodules in the brain and linear enhancement in the leptomeninges were the main features; stick-shaped enhancement was the characteristic sign of the disease on Gd-DTPA enhanced-T1 weighted images.
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Affiliation(s)
- E Jin
- Department of Radiology, Beijing Friendship Hospital affiliate of Capital University of Medical Sciences, 95 Yong-An Road, Beijing 100050, China.
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He Y, Gan S. Identical promoter elements are involved in regulation of the OPR1 gene by senescence and jasmonic acid in Arabidopsis. Plant Mol Biol 2001; 47:595-605. [PMID: 11725945 DOI: 10.1023/a:1012211011538] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Like other developmental processes, the terminal phase of leaf development, generally referred to as leaf senescence. regulates a subset of genes whose transcript abundances are increased during senescence. Jasmonic acid (JA), a plant growth regulator, also regulates the expression of subsets of genes in many aspects of plant growth and development, including leaf senescence. However, the underlying molecular mechanisms by which senescence and JA modulate gene expression are poorly understood. During an effort to isolate senescence-associated genes, we identified an Arabidopsis enhancer trap line in which the reporter gene GUS is up-regulated by both senescence and JA. The T-DNA tagged gene was subsequently cloned using thermal asymmetric interlaced PCR (TAIL-PCR). This gene encodes a 12-oxo-phytodienoic acid-10,11-reductase (OPR1). Consistent with the GUS expression data, RNA gel blot analysis showed that OPR1 was indeed up-regulated by both senescence and JA. Promoter deletion analysis and linker-scanning mutagenesis assays were employed to unveil the molecular bases of OPR1 regulation by senescence and JA. Two regulatory cis elements, namely JASE1 (5'-CGTCAATGAA-3') and JASE2 (5'-CATACGTCGTCAA-3'), in the promoter region of the gene, were identified. While JASE2 contains a mixed A/C box-like motif, JASE1 represents a new motif without any signature sequence so far reported. Both elements were required for the up-regulation of OPR1 by leaf senescence and JA. suggesting that leaf senescence and JA may share a common molecular mechanism for modulating OPR1.
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Affiliation(s)
- Y He
- Plant Physiology/Biochemistry/Molecular Biology Program, Department of Agronomy and Tobacco and Health Research Institute, University of Kentucky, Lexington 40546-0236, USA
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22
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Abstract
A typical eukaryotic promoter consists of a minimal promoter and other upstream cis elements. The minimal promoter is essentially a TATA box region where RNA polymerase II, TATA-binding protein (TBP), and TBP-associated factors (TAFs) bind to initiate transcription, but minimal promoters alone have no transcriptional activity. The cis elements, to which tissue-specific or development-specific transcription factors bind, individually or in combination, determine the spatio-temporal expression pattern of a promoter at the transcriptional level. The arrangement of upstream cis elements followed by a minimal promoter sets the polarity of the promoter. Promoters in plants that have been cloned and widely used for both basic research and biotechnological application are generally unidirectional, directing only one gene that has been fused at its 3' end (downstream). It is often necessary to introduce multiple genes into plants for metabolic engineering and trait stacking. It is also desirable to minimize or avoid repeated use of a single promoter that may cause transcriptional gene silencing. Here we describe a strategy to make polar promoters bidirectional so that one promoter can direct the expression of two genes, one on each end of the promoter.
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Affiliation(s)
- M Xie
- Plant Physiology/Biochemistry/Molecular Biology Program, Department of Agronomy and Tobacco and Health Research Institute, University of Kentucky, Lexington, KY 40546-0236, USA
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23
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He Y, Tang W, Swain JD, Green AL, Jack TP, Gan S. Networking senescence-regulating pathways by using Arabidopsis enhancer trap lines. Plant Physiol 2001; 126:707-16. [PMID: 11402199 PMCID: PMC111161 DOI: 10.1104/pp.126.2.707] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2001] [Revised: 03/26/2001] [Accepted: 04/03/2001] [Indexed: 05/18/2023]
Abstract
The last phase of leaf development, generally referred to as leaf senescence, is an integral part of plant development that involves massive programmed cell death. Due to a sharp decline of photosynthetic capacity in a leaf, senescence limits crop yield and forest plant biomass production. However, the biochemical components and regulatory mechanisms underlying leaf senescence are poorly characterized. Although several approaches such as differential cDNA screening, differential display, and cDNA subtraction have been employed to isolate senescence-associated genes (SAGs), only a limited number of SAGs have been identified, and information regarding the regulation of these genes is fragmentary. Here we report on the utilization of enhancer trap approach toward the identification and analysis of SAGs. We have developed a sensitive large-scale screening method and have screened 1,300 Arabidopsis enhancer trap lines and have identified 147 lines in which the reporter gene GUS (beta-glucuronidase) is expressed in senescing leaves but not in non-senescing ones. We have systematically analyzed the regulation of beta-glucuronidase expression in 125 lines (genetically, each contains single T-DNA insertion) by six senescence-promoting factors, namely abscisic acid, ethylene, jasmonic acid, brassinosteroid, darkness, and dehydration. This analysis not only reveals the complexity of the regulatory circuitry but also allows us to postulate the existence of a network of senescence-promoting pathways. We have also cloned three SAGs from randomly selected enhancer trap lines, demonstrating that reporter expression pattern reflects the expression pattern of the endogenous gene.
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Affiliation(s)
- Y He
- Plant Physiology/Biochemistry/Molecular Biology Program, Department of Agronomy and Tobacco and Health Research Institute, University of Kentucky, Lexington, Kentucky 40546-0236, USA
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24
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Wang E, Wang R, DeParasis J, Loughrin JH, Gan S, Wagner GJ. Suppression of a P450 hydroxylase gene in plant trichome glands enhances natural-product-based aphid resistance. Nat Biotechnol 2001; 19:371-4. [PMID: 11283597 DOI: 10.1038/86770] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [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: 11/08/2022]
Abstract
Trichome glands on the surface of many higher plants produce and secrete exudates affecting insects, microbes, and herbivores. Metabolic engineering of gland exudation has potential for improving pest/disease resistance, and for facilitating molecular farming. We identified a cytochrome P450 hydroxylase gene specific to the trichome gland and used both antisense and sense co-suppression strategies to investigate its function. P450-suppressed transgenic tobacco plants showed a > or =41% decrease in the predominant exudate component, cembratriene-diol (CBT-diol), and a > or =19-fold increase in its precursor, cembratriene-ol (CBT-ol). Thus, the level of CBT-ol was raised from 0.2 to > or =4.3% of leaf dry weight. Exudate from antisense-expressing plants had higher aphidicidal activity, and transgenic plants with exudate containing high concentrations of CBT-ol showed greatly diminished aphid colonization responses. Our results demonstrate the feasibility of significantly modifying the natural-product chemical composition and aphid-interactive properties of gland exudates using metabolic engineering. The results also have implications for molecular farming.
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Affiliation(s)
- E Wang
- Plant Physiology/Biochemistry/Molecular Biology Program, Agronomy Department, N212 ASCN, University of Kentucky, Lexington, KY 40546-0091, USA
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25
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Gan S, Liang Y, Baer DR, Sievers MR, Herman GS, Peden CHF. Effect of Platinum Nanocluster Size and Titania Surface Structure upon CO Surface Chemistry on Platinum-Supported TiO2(110). J Phys Chem B 2001. [DOI: 10.1021/jp003125z] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Chernicky CL, Yi L, Tan H, Gan SU, Ilan J. Treatment of human breast cancer cells with antisense RNA to the type I insulin-like growth factor receptor inhibits cell growth, suppresses tumorigenesis, alters the metastatic potential, and prolongs survival in vivo. Cancer Gene Ther 2000; 7:384-95. [PMID: 10766344 DOI: 10.1038/sj.cgt.7700126] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [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: 11/09/2022]
Abstract
The type I insulin-like growth factor receptor (IGF-IR) plays an important role in the growth and transformation of breast cancer cells. In this study, we investigated the effects of treatment with an antisense IGF-IR construct on cells from the highly metastatic estrogen receptor-negative human breast cancer cell line MDA-MB-435s. The cells carrying the antisense IGF-IR had a markedly reduced expression of IGF-IR, had a significant decrease in cell proliferation, and lost the ability to form colonies in soft agar. There was a delay in tumor formation and a dramatic reduction in tumor size when cells carrying the antisense IGF-IR were injected into either nude or severe combined immunodeficient (scid) beige mice. We have also provided data that show that the scid beige mouse is a more suitable model for studying metastasis of the MDA-MB-435s cells. All of the scid beige mice injected with cells carrying the control construct had metastasis to the lungs, whereas lungs from the nude mice had no apparent metastatic sites after 11 weeks. When cells carrying antisense IGF-IR were injected subcutaneously in scid beige mice, the animals had a significant increase in survival compared with mice injected with cells carrying the control construct. Taken together, these results indicate that the IGF-IR can play a critical role in the progression of breast cancer. Our studies provide a basis for the development of future treatment strategies targeting the IGF-IR in metastatic breast cancer.
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MESH Headings
- Adult
- Animals
- Antineoplastic Agents/therapeutic use
- Breast Neoplasms/mortality
- Breast Neoplasms/pathology
- Breast Neoplasms/therapy
- Carcinoma, Ductal, Breast/mortality
- Carcinoma, Ductal, Breast/pathology
- Carcinoma, Ductal, Breast/secondary
- Carcinoma, Ductal, Breast/therapy
- Disease Models, Animal
- Female
- Humans
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Mice, SCID
- RNA, Antisense/genetics
- RNA, Antisense/therapeutic use
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/therapeutic use
- Tumor Cells, Cultured
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Affiliation(s)
- C L Chernicky
- Department of Reproductive Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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27
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Galea-Lauri J, Darling D, Gan SU, Krivochtchapov L, Kuiper M, Gäken J, Souberbielle B, Farzaneh F. Expression of a variant of CD28 on a subpopulation of human NK cells: implications for B7-mediated stimulation of NK cells. J Immunol 1999; 163:62-70. [PMID: 10384100] [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: 02/13/2023]
Abstract
The ability of NK cells to kill tumor cells is controlled by a balance between activating and inhibitory signals transduced by distinct receptors. In murine tumor models, the costimulatory molecule B7.1 not only acts as a positive trigger for NK-mediated cytotoxicity but can also overcome negative signaling transduced by MHC class I molecules. In this study, we have evaluated the potential of human B7.1-CD28 interaction as an activating trigger for human blood NK cells. Using multiparameter flow cytometric analysis and a panel of different CD28 mAbs, we show that human peripheral blood NK cells (defined by CD56+, CD16+, and CD3- surface expression) express the CD28 costimulatory receptor, with its detection totally dependent on the mAb used. In addition, the level of CD28 varies among individuals and on different NK cell lines, irrespective of CD28 steady-state mRNA levels. By performing Ab binding studies on T cells, our data strongly suggest that binding of two of the anti-CD28 Abs (clones 9.3 and CD28.2) is to a different epitope to that recognized by clones L293 and YTH913.12, which is perhaps modified in the CD28 molecule expressed by the NK cells. We also show that B7.1 enhances the NK-mediated lysis of NK-sensitive but not of NK-resistant tumor cells and that this increased lysis is dependent on CD28-B7 interactions as shown by the ability of Abs to block this lysis. Coculture of the B7.1-positive NK-sensitive cells also led to the activation of the NK cells, as determined by the expression of CD69, CD25, and HLA class II.
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MESH Headings
- Adult
- Animals
- Antibodies, Monoclonal/metabolism
- Antigens, CD/biosynthesis
- Antigens, Differentiation, T-Lymphocyte/biosynthesis
- B-Lymphocytes/immunology
- B7-1 Antigen/physiology
- Binding Sites, Antibody
- CD28 Antigens/biosynthesis
- CD28 Antigens/blood
- CD28 Antigens/genetics
- Cell Separation
- Cells, Cultured
- Clone Cells
- Coculture Techniques
- Cytotoxicity, Immunologic/immunology
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- HLA Antigens/biosynthesis
- Histocompatibility Antigens Class II/biosynthesis
- Humans
- K562 Cells/immunology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Lectins, C-Type
- Lymphocyte Activation/immunology
- Lymphocyte Subsets/immunology
- Lymphocyte Subsets/metabolism
- Mice
- Middle Aged
- RNA, Messenger/biosynthesis
- Receptors, Interleukin-2/biosynthesis
- Sarcoma, Experimental/immunology
- Species Specificity
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Transcription, Genetic/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- J Galea-Lauri
- Immune Gene Therapy Group, Department of Molecular Medicine, King's College School of Medicine and Dentistry, The Rayne Institute, London, United Kingdom
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Pontier D, Gan S, Amasino RM, Roby D, Lam E. Markers for hypersensitive response and senescence show distinct patterns of expression. Plant Mol Biol 1999; 39:1243-55. [PMID: 10380810 DOI: 10.1023/a:1006133311402] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Controlled cellular suicide is an important process that can be observed in various organs during plant development. From the generation of proper sexual organs in monoecious plants to the hypersensitive response (HR) that occurs during incompatible pathogen interactions, programmed cell death (PCD) can be readily observed. Although several biochemical and morphological parameters have been described for various types of cell death in plants, the relationships existing between those different types of PCD events remain unclear. In this work, we set out to examine if two early molecular markers of HR cell death (HIN1 and HSR203J) as well as a senescence marker (SAG12) are coordinately induced during these processes. Our result indicates that although there is evidence of some cross-talk between both cell death pathways, spatial and temporal characteristics of activation for these markers during hypersensitive response and senescence are distinct. These observations indicate that these markers are relatively specific for different cell death programs. Interestingly, they also revealed that a senescence-like process seems to be triggered at the periphery of the HR necrotic lesion. This suggests that cells committed to die during the HR might release a signal able to induce senescence in the neighboring cells. This phenomenon could correspond to the establishment of a second barrier against pathogens. Lastly, we used those cell death markers to better characterize cell death induced by copper and we showed that this abiotic induced cell death presents similarities with HR cell death.
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Affiliation(s)
- D Pontier
- Center for Agricultural Molecular Biology, Rutgers, The State University of New Jersey, Cook College, New Brunswick, 08901-0231, USA
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29
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Gorodeski GI, Burfeind P, Gan SU, Pal D, Abdul-Karim FW. Regulation by retinoids of P2Y2 nucleotide receptor mRNA in human uterine cervical cells. Am J Physiol 1998; 275:C758-65. [PMID: 9730959 DOI: 10.1152/ajpcell.1998.275.3.c758] [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] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular ATP stimulates acute changes in paracellular permeability across cultures of human uterine cervical epithelial cells [G. I. Gorodeski, D. E. Peterson, B. J. De Santis, and U. Hopfer. Am. J. Physiol. 270 (Cell Physiol. 39): C1715-C1725, 1996]. In this paper, we characterize mRNA for a P2Y2 nucleotide receptor in human cervical cells. Using oligonucleotide primers based on the sequence of human airway epithelium P2Y2 receptor, a single 632-bp cDNA band was identified in RT-PCR experiments in extracts of human endocervical and ectocervical tissues and in lysates of human cervical CaSki cells, but not in 3T3 fibroblasts. The nucleotide sequence was homologous to the corresponding human airway epithelium P2Y2 receptor. Northern blot analyses revealed hybridization of the P2Y2 receptor probe to a 2.0-kb mRNA fragment, as well as to 2.2-, 3. 0-, and 4.6-kb species, indicating that human cervical cells express P2Y2 receptor mRNA. Incubation of CaSki cells in retinoid-free medium abolished the ATP-induced changes in permeability and decreased the expression of the P2Y2 receptor mRNA; treatment with retinoids restored the responses to ATP and upregulated the P2Y2 receptor mRNA, suggesting that the receptor mediates ATP-related changes in permeability. Treatment with actinomycin D decreased the expression of the P2Y2 receptor RNA, but the ratio density of the receptor RNA relative to glyceraldehyde-3-phosphate dehydrogenase RNA remained unchanged, suggesting that retinoids upregulate transcription of the receptor mRNA. We conclude that retinoid-dependent modulation of the P2Y2 receptor expression, and hence of the responses to ATP, may be an important mechanism for the regulation of secretion of cervical mucus in vivo.
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Affiliation(s)
- G I Gorodeski
- Department of Reproductive Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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30
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Weaver LM, Gan S, Quirino B, Amasino RM. A comparison of the expression patterns of several senescence-associated genes in response to stress and hormone treatment. Plant Mol Biol 1998; 37:455-69. [PMID: 9617813 DOI: 10.1023/a:1005934428906] [Citation(s) in RCA: 341] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The expression of several Arabidopsis thaliana senescence-associated genes (SAGs) in attached and/or detached leaves was compared in response to age, dehydration, darkness, abscisic acid, cytokinin, and ethylene treatments. Most of the SAGs responded to most of the treatments in a similar fashion. Detachment in darkness and ethylene were the strongest inducers of both SAGs and visible yellowing. Detachment in light was also a strong inducer of SAGs, but not of visible yellowing. The other treatments varied more in their effects on individual SAGs. Responses were examined in both older and younger leaves, and generally were much stronger in the older ones. Individual SAGs differed from the norms in different ways, however, suggesting that their gene products play a role in overlapping but not identical circumstances. Some SAGs responded quickly to treatments, which may indicate a direct response. Others responded more slowly, which may indicate an indirect response via treatment-induced senescence. Four new SAGs were isolated as part of this work, one of which shows strong similarity to late embryogenesis-abundant (Lea) genes.
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Affiliation(s)
- L M Weaver
- Dept. of Biochemistry, University of Wisconsin at Madison, 53706, USA
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31
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Gan S. Gender Differences in Care of Medicare Patients With Myocardial Infarction: National Results and Regional Variations From the Cooperative Cardiovascular Project (CCP). J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(97)88284-8] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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32
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Gan S, Amasino RM. Making Sense of Senescence (Molecular Genetic Regulation and Manipulation of Leaf Senescence). Plant Physiol 1997; 113:313-319. [PMID: 12223609 PMCID: PMC158144 DOI: 10.1104/pp.113.2.313] [Citation(s) in RCA: 408] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- S. Gan
- Department of Biochemistry, University of Wisconsin, 420 Henry Mall, Madison, Wisconsin 53706-1569
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33
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Gäken JA, Tavassoli M, Gan SU, Vallian S, Giddings I, Darling DC, Galea-Lauri J, Thomas MG, Abedi H, Schreiber V, Ménissier-de Murcia J, Collins MK, Shall S, Farzaneh F. Efficient retroviral infection of mammalian cells is blocked by inhibition of poly(ADP-ribose) polymerase activity. J Virol 1996; 70:3992-4000. [PMID: 8648736 PMCID: PMC190277 DOI: 10.1128/jvi.70.6.3992-4000.1996] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [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: 02/01/2023] Open
Abstract
Integration of proviral DNA into the host cell genome is a characteristic feature of the retroviral life cycle. This process involves coordinate DNA strand break formation and rejoining reactions. The full details of the integration process are not yet fully understood. However, the endonuclease and DNA strand-joining activities of the virus-encoded integrase protein (IN) are thought to act in concert with other, as-yet-unidentified, endogenous nuclear components which are involved in the DNA repair process. The nuclear enzyme poly(ADP-ribose) polymerase (PARP), which is dependent on DNA strand breaks for its activity, is involved in the efficient repair of DNA strand breaks, and maintenance of genomic integrity, in nucleated eukaryotic cells. In the present work, we examine the possible involvement of PARP in the retroviral life cycle and demonstrate that inhibition of PARP activity, by any one of three independent mechanisms, blocks the infection of mammalian cells by recombinant retroviral vectors. This requirement for PARP activity appears to be restricted to processes involved in the integration of provirus into the host cell DNA. PARP inhibition does not affect viral entry into the host cell, reverse transcription of the viral RNA genome, postintegration synthesis of viral gene products, synthesis of the viral RNA genome, or the generation of infective virions. Therefore, efficient retroviral infection of mammalian cells is blocked by inhibition or PARP activity.
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Affiliation(s)
- J A Gäken
- Department of Molecular Medicine, The Rayne Institute, King's College School of Medicine & Dentistry, London, United Kingdom
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Volpi EV, Vatcheva R, Labella T, Gan SU. More detailed characterization of some of the HL60 karyotypic features by fluorescence in situ hybridization. Cancer Genet Cytogenet 1996; 87:103-6. [PMID: 8625253 DOI: 10.1016/0165-4608(95)00214-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We performed a focused chromosome analysis on the HL60 cell line by multicolor fluorescence in situ hybridization (FISH), using probes for the unequivocal identification of specific chromosome regions and subregions. The purpose of this karyotypic re-evaluation was to confirm and to characterize in more detail chromosome rearrangements already identified by means of classic cytogenetic approaches and recurrently detected from the initial establishment of the cell line. The observations reported may help reassess the potential of the HL60 cell line in understanding the molecular events underlying the non-random karyotype alterations associated with acute myeloid leukemias (AML).
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Affiliation(s)
- E V Volpi
- Istituto di Genetica Molecolare del CNR, Alghero, Italy
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35
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Abstract
Controlling expression of IPT, a gene encoding isopentenyltransferase (the enzyme that catalyzes the rate-limiting step in cytokinin biosynthesis), with a senescence-specific promoter results in the suppression of leaf senescence. Transgenic tobacco plants expressing this chimeric gene do not exhibit the developmental abnormalities usually associated with IPT expression because the system is autoregulatory. Because sufficient cytokinin is produced to retard senescence, the activity of the senescence-specific promoter is attenulated. Senescence-retarded leaves exhibit a prolonged, photosythetically active life-span. This result demonstrates that endogenously produced cytokinin can regulate senescence and provides a system to specifically manipulate the senescence program.
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Affiliation(s)
- S Gan
- Department of Biochemistry, University of Wisconsin, Madison, 53706-1569, USA
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36
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Morecki S, Nagler A, Puyesky Y, Nabet C, Condiotti R, Pick M, Gan S, Slavin S. Effect of various cytokine combinations on induction of non-MHC-restricted cytotoxicity. Lymphokine Cytokine Res 1993; 12:159-165. [PMID: 8347764] [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: 05/22/2023]
Abstract
Efforts were directed to achieve an increased lymphokine-activated non-MHC-restricted killing (LAK) activity greater than that induced by rIL-2 alone. Human peripheral blood (PB) and bone marrow (BM)-derived mononuclear cells (MC) were exposed in vitro to multiple cytokine combinations, including rIL-6, rIL-7, rIFN-alpha and rIFN-gamma in the presence of either suboptimal or optimal doses of rIL-2. Our results have shown that BMMC are a potential source for induction of increased LAK activity upon exposure to multiple cytokine combinations, whereas PBMC could not be successfully stimulated under the same conditions. Fifty-five to 62% of BM-derived samples stimulated with high dose rIL-2 + rIL-7 or rIL-2 + rIL-7 + rIL-6 + rIFN-gamma exhibited a higher degree of cytotoxicity than BM samples stimulated with rIL-2 alone. Exposure of PB-derived large granular lymphocytes (LGL) to various cytokine combinations led to increased proliferation after stimulation with suboptimal dose of rIL-2 in the presence of rIL-6 and rIL-7. This increase was not observed in induction of cytotoxicity. We suggest that BMMC activated by multiple cytokine combinations could play an active role in improving antitumor response in vivo by contributing to the control of minimal residual tumor cell growth, particularly post-BM transplantation.
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Affiliation(s)
- S Morecki
- Department of Bone Marrow Transplantation, Hadassah University Hospital, Jerusalem, Israel
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37
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Nagler A, Mumcuoglu M, Naparstek E, Or R, Gan S, Slavin S. Normal hematopoietic reconstitution following ASTA-Z 7557-purged grafts in the absence of in vitro CFU-GM colony growth. Leuk Res 1993; 17:61-7. [PMID: 8429681 DOI: 10.1016/0145-2126(93)90142-8] [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: 01/30/2023]
Abstract
Hematopoietic reconstitution was assessed in 26 consecutive patients who underwent autologous bone marrow transplantation (ABMT) with ASTA-Z 7557 purged bone marrows. Of the 26, 17 had acute non-lymphoblastic leukemia (ANLL), 7 had acute lymphoblastic leukemia (ALL), 1 had non-Hodgkin's lymphoma (NHL) and 1 had multiple myeloma (MM). Twelve patients had practically no CFU-GM growth after ASTA-Z treatment. No statistical difference was observed in hematopoietic reconstitution between patients with or without in vitro CFU-GM colony growth. No significant linear correlation was observed between CFU-GM content in the treated graft and day of engraftment. In vitro CFU-GM growth has no predictive value in assessing hematopoietic recovery in vivo. Patients with no CFU-GM growth demonstrated normal engraftment.
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Affiliation(s)
- A Nagler
- Department of Bone Marrow Transplantation, Hadassah University Hospital, Jerusalem, Israel
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38
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Gan S, Seferis JC, Prime RB. A viscoelastic description of the glass transition-conversion relationship for reactive polymers. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf01913098] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Gan S, Gillham JK, Prime RB. A methodology for characterizing reactive coatings: Time–temperature–transformation (TTT) analysis of the competition between cure, evaporation, and thermal degradation for an epoxy-phenolic system. J Appl Polym Sci 1989. [DOI: 10.1002/app.1989.070370316] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Affiliation(s)
- S Gan
- Department of Epidemiology, Chinese Academy of Preventive Medicine, Beijing
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Chumakov MP, Gavrilovskaia IN, Linev MB, Gorbachkova EA, Gan S. [Use of monoclonal antibodies for differentiating strains of the virus causing the hemorrhagic fever with renal syndrome]. Vopr Virusol 1987; 32:604-7. [PMID: 3124351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Using monoclonal antibody and animal immune sera the experiment confirmed the existence of antigenic relationships between the strains of virus of hemorrhagic fever with renal syndrome (HFRS) isolated in the USSR from Clethrionomys glareolus and members of all known serotypes of HFRS virus. Clear-cut differentiation was made from serotypes Apodemus and Rattus, and cross-relationships were shown between the strains isolated in the USSR and Prospect Hill virus (PHV), a member of the serotype Microtus isolated in the USA.
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