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Cruz JC, Martins CK, Piassi JEV, Garcia Júnior IR, Santiago Junior JF, Faverani LP. Does chlorhexidine reduce the incidence of ventilator-associated pneumonia in ICU patients? A systematic review and meta-analysis. Med Intensiva 2023; 47:437-444. [PMID: 36464582 DOI: 10.1016/j.medine.2022.11.002] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/12/2022] [Accepted: 10/20/2022] [Indexed: 06/17/2023]
Abstract
OBJECTIVE This study aimed to investigate chlorhexidine's efficacy in preventing ventilator-associated pneumonia (VAP). DESIGN A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. SETTINGS The data were obtained from Pubmed, Cochrane Library, and EMBASE. PATIENTS OR PARTICIPANTS Only mechanically ventilated patients for at least 48h were included. INTERVENTIONS Randomized clinical trials applying any dosage form of chlorhexidine were eligible. MAIN VARIABLES OF INTEREST The relative risk (RR) of the VAP incidence and all-cause mortality was assessed using the random-effects model. The mean difference in days of mechanical ventilation duration and intensive care unit (ICU) length of stay were also appraised. RESULTS Ten studies involving 1233 patients were included in the meta-analysis. The oral application of CHX reduced the incidence of VAP (RR, 0.73 [95% CI, 0.55, 0.97]) and did not show an increase in all-cause mortality (RR, 1.13 [95% CI, 0.96, 1.32]). CONCLUSIONS CHX proved effective to prevent VAP. However, a conclusion on mortality rates could not be drawn because the quality of the evidence was very low for this outcome.
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Affiliation(s)
- J C Cruz
- University of São Paulo (USP), Ribeirão Preto, Brazil.
| | - C K Martins
- Department of Medicine, University of Ribeirão Preto (UNAERP), Ribeirão Preto, Brazil
| | - J E V Piassi
- Division of Oral and Maxillofacial Surgery, Department of Diagnosis and Surgery, São Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
| | - I R Garcia Júnior
- Division of Oral and Maxillofacial Surgery, Department of Diagnosis and Surgery, São Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
| | - J F Santiago Junior
- Department of Health Sciences. Dentistry Course, Unisagrado: Centro Universitário Sagrado Coração, Bauru, SP, Brazil
| | - L P Faverani
- Division of Oral and Maxillofacial Surgery, Department of Diagnosis and Surgery, São Paulo State University (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil
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Cruz Cruz J, Allison KC, Page LS, Jenkins AJ, Wang X, Earp HS, Frye SV, Graham DK, Verneris MR, Lee-Sherick AB. Inhibiting efferocytosis reverses macrophage-mediated immunosuppression in the leukemia microenvironment. Front Immunol 2023; 14:1146721. [PMID: 36960055 PMCID: PMC10027704 DOI: 10.3389/fimmu.2023.1146721] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 02/20/2023] [Indexed: 03/09/2023] Open
Abstract
Background Previous studies show that the spleen and bone marrow can serve as leukemia microenvironments in which macrophages play a significant role in immune evasion and chemoresistance. We hypothesized that the macrophage driven tolerogenic process of efferocytosis is a major contributor to the immunosuppressive leukemia microenvironment and that this was driven by aberrant phosphatidylserine expression from cell turnover and cell membrane dysregulation. Methods Since MerTK is the prototypic efferocytosis receptor, we assessed whether the MerTK inhibitor MRX2843, which is currently in clinical trials, would reverse immune evasion and enhance immune-mediated clearance of leukemia cells. Results We found that inhibition of MerTK decreased leukemia-associated macrophage expression of M2 markers PD-L1, PD-L2, Tim-3, CD163 and Arginase-1 compared to vehicle-treated controls. Additionally, MerTK inhibition led to M1 macrophage repolarization including elevated CD86 and HLA-DR expression, and increased production of T cell activating cytokines, including IFN-β, IL-18, and IL-1β through activation of NF-κB. Collectively, this macrophage repolarization had downstream effects on T cells within the leukemia microenvironment, including decreased PD-1+Tim-3+ and LAG3+ checkpoint expression, and increased CD69+CD107a+ expression. Discussion These results demonstrate that MerTK inhibition using MRX2843 altered the leukemia microenvironment from tumor-permissive toward immune responsiveness to leukemia and culminated in improved immune-mediated clearance of AML.
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Affiliation(s)
- Joselyn Cruz Cruz
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
| | - Kristen C. Allison
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
| | - Lauren S. Page
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
| | - Alexis J. Jenkins
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
| | - Xiaodong Wang
- Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - H. Shelton Earp
- Lineberger Comprehensive Cancer Center, Departments of Medicine and Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Stephen V. Frye
- Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Douglas K. Graham
- Department of Pediatrics, Emory University, Atlanta, GA, United States
| | - Michael R. Verneris
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
| | - Alisa B. Lee-Sherick
- Division of Pediatric Hematology, Oncology, and Bone Marrow Transplant, University of Colorado, Aurora, CO, United States
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Chetty SL, Liu Y, Cole A, Cruz JC, Hoffmeyer E, Vibhakar R, Venkataraman S, Mitra S. EXTH-18. TARGETING THE ADENOSINERGIC IMMUNE SUPPRESSION PATHWAY IN HIGH GRADE GLIOMA SYNERGIZES WITH INNATE IMMUNE CHECKPOINT BLOCKADE. Neuro Oncol 2022. [PMCID: PMC9661160 DOI: 10.1093/neuonc/noac209.817] [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: 11/16/2022] Open
Abstract
Abstract
Immune response in the tumor microenvironment is modulated by the conversion of eATP to AMP to adenosine via the ecto-enzymes CD39 and CD73. Overexpression of CD73 in tumors leads to an increase in extracellular adenosine concentration and decrease in eATP, resulting in immune suppression. In this study, CD73 knockouts were created in adult and pediatric glioma cell lines (DIPG17, T3691, BT245) and used to quantify the effects of CD73 knockout on macrophage phagocytosis in the presence of extracellular AMP. In cell line DIPG17, CD73 knockout significantly increased phagocytosis with and without external AMP compared to the WT. In the WT condition, addition of AMP significantly reduced phagocytosis, while this decrease was not significant in the CD73-KO. The addition of anti-CD47 antibody significantly increased phagocytosis with external AMP in the WT condition. Similar results were obtained with cell line T3691. However, CD73 knockout combined with anti-CD47 treatment and external AMP showed significantly greater phagocytosis than the WT condition. This suggests that a combination of anti-CD73 and anti-CD47 treatment may be more effective in the tumor microenvironment. Lastly, in cell line BT245, CD73 knockout significantly increased phagocytosis as seen in the other cell lines. However, no significant difference was observed between WT and CD73-KO with extracellular AMP or anti-CD47. In vivo studies were conducted in orthotopic xenograft mouse models with DIPG17 CD73 knockout cells. Combination treatment with anti-CD47 antibody significantly decreased tumor burden and prolonged survival in the CD73-KO tumors compared to anti-CD47 treated DIPG17-WT tumors. We conclude that the CD73 adenosinergic pathway and the CD47-SIRPα pathway may present a target for immunotherapy in pediatric and adult gliomas.
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Affiliation(s)
| | - Yifan Liu
- University of Colorado, Anschutz Medical Campus , LONGMONT, CO , USA
| | - Allison Cole
- University of Colorado, Anschutz Medical Campus , Aurora, CO , USA
| | | | - Eric Hoffmeyer
- University of Colorado, Anschutz Medical Campus , Aurora, CO , USA
| | | | | | - Siddhartha Mitra
- University of Colorado, AMC and Children's Hospital Colorado , Aurora, CO , USA
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Mitra S, Picard D, Qin N, Cole A, Cruz JC, Marquardt V, Venkataraman S, Vibhakar R, Remke M. IMMU-38. MYC DRIVEN IMMUNE SUPPRESSION IN GROUP 3 MEDULLOBLASTOMA. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac209.535] [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: 11/16/2022] Open
Abstract
Abstract
BACKGROUND
The expression of MYC in tumor cells regulates the tumor microenvironment through innate and adaptive immune effector cells and immune regulatory cytokines. MYC has also been shown to regulate the expression of the immune checkpoint gene products CD47 and programmed death-ligand 1 (PD-L1). While PD-L1 inhibits adaptive immune response, CD47 on tumor cells binds to SIRPa on macrophages and acts as a “Don’t eat me” signal. We have previously shown that blocking the CD47-SIRPa pathway significantly decreases tumor burden and increases survival in five etiologically distinct adult and pediatric brain tumor xenograft models, including Group 3 or MYC-driven MB, by activating macrophage-mediated phagocytosis.
METHODS
We performed a primary screen including 78 epigenetic inhibitors and a secondary screen including 20 histone deacetylase inhibitors (HDACi) to compare response profiles in ATRT, medulloblastoma (n = 14), and glioblastoma (n = 14). This unbiased approach revealed the preferential activity of Class I HDACi in MYC-driven medulloblastoma mediated by induction of apoptosis, reduction in MYC transcription, and release of pro-inflammatory cytokines in MYC-driven medulloblastoma, with little to no activity in non-MYC-driven medulloblastoma, AT/RT, and glioblastoma in vitro. In addition, we tested the combinatorial effect of directly targeting the MYC/MAX interaction using MYCI-975 and the CD47-SIRPa phagocytosis checkpoint pathway using in-vitro phagocytosis assays and in-vivo xenograft models. In two orthotopic mouse models of MYC-driven medulloblastoma, MYCi975 displayed anti-tumoral effects at the primary site and the metastatic compartment. Furthermore, RNA sequencing revealed NFκB pathway induction as a response to MYC treatment, followed by interferon-gamma (IFN-G) release and cell surface expression of engulfment (“eat-me”) signals (such as calreticulin) and enhanced in vitro phagocytosis and survival in tumor-bearing mice.
CONCLUSION
Together, these findings suggest a dynamic relationship between MYC amplification and innate immune suppression in MYC-medulloblastoma and support further investigation of phagocytosis modulation as a strategy to enhance cancer immunotherapy responses.
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Affiliation(s)
- Siddhartha Mitra
- University of Colorado, AMC and Children's Hospital Colorado , Aurora, CO , USA
| | - Daniel Picard
- German Cancer Research Center (DKFZ) , Dusseldorf , Germany
| | - Nan Qin
- German Cancer Research Center (DKFZ) , Dusseldorf , Germany
| | - Allison Cole
- University of Colorado, Anschutz Medical Campus , aurora , USA
| | | | | | | | | | - Marc Remke
- German Cancer Research Centre (DKFZ) , Dusseldorf , Germany
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5
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Liu Y, Chetty SL, Cole A, Cruz JC, Hoffmeyer E, Vibhakar R, Venkataraman S, Mitra S. IMMU-21. Targeting the adenosinergic immune suppression pathway in high grade glioma synergizes with innate immune checkpoint blockade. Neuro Oncol 2022. [DOI: 10.1093/neuonc/noac079.314] [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: 11/14/2022] Open
Abstract
Abstract
Immune response in the tumor microenvironment is modulated by the conversion of eATP to AMP to adenosine via the ecto-enzymes CD39 and CD73. Overexpression of CD73 in tumors leads to an increase in extracellular adenosine concentration and decrease in eATP, resulting in immune suppression. In this study, CD73 knockouts were created in adult and pediatric glioma cell lines (DIPG17, T3691, BT245) and used to quantify the effects of CD73 knockout on macrophage phagocytosis in the presence of extracellular AMP. In cell line DIPG17, CD73 knockout significantly increased phagocytosis with and without external AMP compared to the WT. In the WT condition, addition of AMP significantly reduced phagocytosis, while this decrease was not significant in the CD73-KO. The addition of anti-CD47 antibody significantly increased phagocytosis with external AMP in the WT condition. Similar results were obtained with cell line T3691. However, CD73 knockout combined with anti-CD47 treatment and external AMP showed significantly greater phagocytosis than the WT condition. This suggests that a combination of anti-CD73 and anti-CD47 treatment may be more effective in the tumor microenvironment. Lastly, in cell line BT245, CD73 knockout significantly increased phagocytosis as seen in the other cell lines. However, no significant difference was observed between WT and CD73-KO with extracellular AMP or anti-CD47. In vivo studies were conducted in orthotopic xenograft mouse models with DIPG17 CD73 knockout cells. Combination treatment with anti-CD47 antibody significantly decreased tumor burden and prolonged survival in the CD73-KO tumors compared to anti-CD47 treated DIPG13-WT tumors. We conclude that the CD73 adenosinergic pathway and the CD47-SIRPα pathway may present a target for immunotherapy in pediatric and adult gliomas.
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Affiliation(s)
- Yifan Liu
- University of Colorado Boulder , Boulder, CO , USA
| | | | - Allison Cole
- University of Colorado School of Medicine , Aurora, CO , USA
| | | | - Eric Hoffmeyer
- University of Colorado School of Medicine , Aurora, CO , USA
| | - Rajeev Vibhakar
- University of Colorado School of Medicine , Aurora, CO , USA
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6
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Chatwin HV, Cruz Cruz J, Green AL. Pediatric high-grade glioma: moving toward subtype-specific multimodal therapy. FEBS J 2021; 288:6127-6141. [PMID: 33523591 DOI: 10.1111/febs.15739] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [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: 11/20/2020] [Revised: 01/21/2021] [Accepted: 01/27/2021] [Indexed: 12/14/2022]
Abstract
Pediatric high-grade gliomas (pHGG) comprise a deadly, heterogenous category of pediatric gliomas with a clear need for more effective treatment options. Advances in high-throughput molecular techniques have enhanced molecular understanding of these tumors, but outcomes are still poor, and treatments beyond resection and radiation have not yet been clearly established as standard of care. In this review, we first discuss the history of treatment approaches to pHGG to this point. We then review four distinct categories of pHGG, including histone 3-mutant, IDH-mutant, histone 3/IDH-wildtype, and radiation-induced pHGG. We discuss the molecular understanding of each subgroup and targeted treatment options in development. Finally, we look at the development and current status of two novel approaches to pHGG as a whole: localized convection-enhanced chemotherapy delivery and immunotherapy, including checkpoint inhibitors, vaccine therapy, and CAR-T cells. Through this review, we demonstrate the potential for rational, molecularly driven, subtype-specific therapy to be used with other novel approaches in combinations that could meaningfully improve the prognosis in pHGG.
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Affiliation(s)
- Hannah V Chatwin
- Department of Pediatrics, Morgan Adams Foundation Pediatric Brain Tumor Research Program, University of Colorado School of Medicine, Aurora, CO, USA
| | - Joselyn Cruz Cruz
- Department of Pediatrics, Morgan Adams Foundation Pediatric Brain Tumor Research Program, University of Colorado School of Medicine, Aurora, CO, USA
| | - Adam L Green
- Department of Pediatrics, Morgan Adams Foundation Pediatric Brain Tumor Research Program, University of Colorado School of Medicine, Aurora, CO, USA.,Center for Cancer and Blood Disorders, Children's Hospital Colorado, Aurora, CO, USA
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7
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Souza MM, Vechiato FMV, Debarba LK, Leao RM, Dias MVS, Pereira AA, Cruz JC, Elias LLK, Antunes-Rodrigues J, Ruginsk SG. Effects of Hyperosmolality on Hypothalamic Astrocytic Area, mRNA Expression and Glutamate Balance In Vitro. Neuroscience 2020; 442:286-295. [PMID: 32599125 DOI: 10.1016/j.neuroscience.2020.06.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 11/17/2022]
Abstract
During prolonged dehydration, body fluid homeostasis is challenged by extracellular fluid (ECF) hyperosmolality, which induce important functional changes in the hypothalamus, in parallel with other effector responses, such as the activation of the local renin-angiotensin system (RAS). Therefore, in the present study we investigated the role of sodium-driven ECF hyperosmolality on glial fibrillary acid protein (GFAP) immunoreactivity and protein expression, membrane capacitance, mRNA expression of RAS components and glutamate balance in cultured hypothalamic astrocytes. Our data show that hypothalamic astrocytes respond to increased hyperosmolality with a similar decrease in GFAP expression and membrane capacitance, indicative of reduced cellular area. Hyperosmolality also downregulates the transcript levels of angiotensinogen and both angiotensin-converting enzymes, whereas upregulates type 1a angiotensin II receptor mRNA. Incubation with hypertonic solution also decreases the immunoreactivity to the membrane glutamate/aspartate transporter (GLAST) as well as tritiated-aspartate uptake by astrocytes. This latter effect is completely restored to basal levels when astrocytes previously exposed to hypertonicity are incubated under isotonic conditions. Together with a direct effect on two important local signaling systems (glutamate and RAS), these synaptic rearrangements driven by astrocytes may accomplish for a coordinated increase in the excitatory drive onto the hypothalamic neurosecretory system, ultimately culminating with increased AVP release in response to hyperosmolality.
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Affiliation(s)
- M M Souza
- Department of Physiological Sciences, Biomedical Sciences Institute, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil
| | - F M V Vechiato
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - L K Debarba
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - R M Leao
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - M V S Dias
- Natural Sciences Institute, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil
| | - A A Pereira
- Food and Drugs Department, Pharmaceutical Sciences Faculty, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil
| | - J C Cruz
- Biotechnology Center, Department of Biotechnology, Federal University of Paraiba, Joao Pessoa, Paraiba, Brazil
| | - L L K Elias
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - J Antunes-Rodrigues
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil
| | - S G Ruginsk
- Department of Physiological Sciences, Biomedical Sciences Institute, Federal University of Alfenas, Alfenas, Minas Gerais, Brazil.
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Fernandes JS, Angelo PCS, Cruz JC, Santos JMM, Sousa NR, Silva GF. Post-transcriptional silencing of the SGE1 gene induced by a dsRNA hairpin in Fusarium oxysporum f. sp cubense, the causal agent of Panama disease. Genet Mol Res 2016; 15:gmr7941. [PMID: 27173186 DOI: 10.4238/gmr.15027941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fusarium oxysporum f. sp cubense (Foc), the causal agent of Panama disease, is responsible for economic losses in banana crops worldwide. The identification of genes that effectively act on pathogenicity and/or virulence may contribute to the development of different strategies for disease control and the production of resistant plants. The objective of the current study was to analyze the importance of SGE1 gene expression in Foc virulence through post-transcriptional silencing using a double-stranded RNA hairpin. Thirteen transformants were selected based on different morphological characteristics, and sporulation in these transformants was significantly reduced by approximately 95% (P < 0.05) compared to that of the wild-type strain. The relative SGE1 expression levels in the transformant strains were reduced by 27 to 47% compared to those in the wild-type strain. A pathogenicity analysis revealed that the transformants were able to reach the rhizomes and pseudostems of the inoculated banana plants. However, the transformants induced initial disease symptoms in the banana plants approximately 10 days later than that by the wild-type Foc, and initial disease symptoms persisted even at 45 days after inoculation. These results indicate that the SGE1 gene is directly involved in the virulence of Foc. Therefore, SGE1 may be a potential candidate for host-induced gene silencing in banana plants.
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Affiliation(s)
- J S Fernandes
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
| | - P C S Angelo
- Embrapa Café - Fundação Procafé, Varginha, MG, Brasil
| | - J C Cruz
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
| | - J M M Santos
- Instituto Nacional de Pesquisa da Amazônia & Universidade do Estado do Amazonas, Manaus, AM, Brasil
| | - N R Sousa
- Embrapa Cocais, São Luiz, MA, Brasil
| | - G F Silva
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
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Bravim A, Sakuraba RK, Cruz JC, Campos LL. OSL and TL response characterization of LiF:MG,Ti microdosimeters to be applied to VMAT quality assurance. Appl Radiat Isot 2015; 105:299-302. [PMID: 26386504 DOI: 10.1016/j.apradiso.2015.08.038] [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: 07/22/2014] [Revised: 08/21/2015] [Accepted: 08/27/2015] [Indexed: 11/25/2022]
Abstract
This paper aims to evaluate the feasibility of applying LiF:Mg,Ti microdosimeters as a new method of dosimetry to volumetric-modulated arc therapy (VMAT) RapidArc. The response of microdosimeters presented a maximum variation of ±3.18% and ±0.510% using optically stimulated luminescence (OSL) and thermoluminescence (TL) techniques, respectively. Although studies were conducted on LiF:Mg,Ti microdosimeters previously, the microdosimeters in this study showed precision and high potential of application in VMAT dosimetry and in the verification of treatment planning using the VMAT technique.
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Affiliation(s)
- A Bravim
- Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes, 2242, Cidade Universitária, São Paulo, SP, Brazil
| | - R K Sakuraba
- Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes, 2242, Cidade Universitária, São Paulo, SP, Brazil; Sociedade Beneficente Israelita Brasileira Hospital Albert Einstein (HIAE), Avenida Albert Einstein, 627/701, São Paulo, Brazil
| | - J C Cruz
- Sociedade Beneficente Israelita Brasileira Hospital Albert Einstein (HIAE), Avenida Albert Einstein, 627/701, São Paulo, Brazil
| | - L L Campos
- Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes, 2242, Cidade Universitária, São Paulo, SP, Brazil
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10
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Souza Á, Nogueira VB, Cruz JC, Sousa NR, Procópio ARL, Silva GF. Operational taxonomic units (OTUs) of endophytic bacteria isolated from banana cultivars in the Amazon. Genet Mol Res 2015; 14:9932-8. [PMID: 26345928 DOI: 10.4238/2015.august.19.28] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Endophytic microorganisms colonize plants, inhibit the growth of pathogens (by competing for nutrients and/or space), or produce antagonistic substances. Fifty-five endophytic bacteria were isolated from the leaf tissue of the FHIA 18 banana cultivar. Genetic diversity analyses were performed using the enterobacterial repetitive intergenic consensus sequence polymerase chain reaction method and BOX molecular markers. These analyses resulted in 33 and 21 polymorphic bands, respectively. The similarity data, obtained using the Dice coefficient based on the polyphasic analysis method, ranged from 22 to 100%. This indicated a high genetic diversity among the analyzed isolates. Sixty percent similarity was utilized as the cut-off criterion for the formation of operational taxonomic units (OTUs); this resulted in the identification of 32 possible OTUs, indicating a high number of potential species.
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Affiliation(s)
- Á Souza
- Universidade do Estado do Amazonas, Manaus, AM, Brasil
| | - V B Nogueira
- Universidade Federal do Amazonas, Manaus, AM, Brasil
| | - J C Cruz
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental/CPAA, Manaus, AM, Brasil
| | - N R Sousa
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental/CPAA, Manaus, AM, Brasil
| | | | - G F Silva
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental/CPAA, Manaus, AM, Brasil
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Abstract
Endophytic microorganisms consist of fungi, bacteria, and actinomycetes that play important roles in the process of plant adaptation to the environment. Currently, the natural associations between microorganisms and plant species are being explored for a large number of biotechnological applications. In this study, 122 endophytic bacteria were isolated from 5 cultivars of Musa spp from the state of Amazonas (Brazil). Four strains were selected because they exhibited antagonistic activities against Fusarium oxysporum f. sp cubense and Colletotrichum guaranicola, with inhibitions ranging from 19 to 30% and 27 to 35%, respectively. Phylogenetic analysis of the 16S rDNA regions of these bacteria with antifungal activity showed that they are phylogenetically related to 3 different species of Bacillus - B. amyloliquefaciens, B. subtilis subsp subtilis, and B. thuringiensis.
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Affiliation(s)
- A Souza
- Laboratório de Biotecnologia e Recursos Naturais, Universidade do Estado do Amazonas, Manaus, AM, Brasil
| | - J C Cruz
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
| | - N R Sousa
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
| | - A R L Procópio
- Laboratório de Biotecnologia e Recursos Naturais, Universidade do Estado do Amazonas, Manaus, AM, Brasil
| | - G F Silva
- Laboratório de Biologia Molecular, Embrapa Amazônia Ocidental, Manaus, AM, Brasil
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12
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Antunes-Rodrigues J, Ruginsk SG, Mecawi AS, Margatho LO, Cruz JC, Vilhena-Franco T, Reis WL, Ventura RR, Reis LC, Vivas LM, Elias LLK. Mapping and signaling of neural pathways involved in the regulation of hydromineral homeostasis. Braz J Med Biol Res 2013; 46:327-38. [PMID: 23579631 PMCID: PMC3854407 DOI: 10.1590/1414-431x20132788] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/05/2013] [Indexed: 11/22/2022] Open
Abstract
Several forebrain and brainstem neurochemical circuitries interact with
peripheral neural and humoral signals to collaboratively maintain both the
volume and osmolality of extracellular fluids. Although much progress has been
made over the past decades in the understanding of complex mechanisms underlying
neuroendocrine control of hydromineral homeostasis, several issues still remain
to be clarified. The use of techniques such as molecular biology, neuronal
tracing, electrophysiology, immunohistochemistry, and microinfusions has
significantly improved our ability to identify neuronal phenotypes and their
signals, including those related to neuron-glia interactions. Accordingly,
neurons have been shown to produce and release a large number of chemical
mediators (neurotransmitters, neurohormones and neuromodulators) into the
interstitial space, which include not only classic neurotransmitters, such as
acetylcholine, amines (noradrenaline, serotonin) and amino acids (glutamate,
GABA), but also gaseous (nitric oxide, carbon monoxide and hydrogen sulfide) and
lipid-derived (endocannabinoids) mediators. This efferent response, initiated
within the neuronal environment, recruits several peripheral effectors, such as
hormones (glucocorticoids, angiotensin II, estrogen), which in turn modulate
central nervous system responsiveness to systemic challenges. Therefore, in this
review, we shall evaluate in an integrated manner the physiological control of
body fluid homeostasis from the molecular aspects to the systemic and integrated
responses.
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Affiliation(s)
- J Antunes-Rodrigues
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
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Bravim A, Sakuraba RK, Cruz JC, Campos LL. Dose-response and intrinsic efficiency of thermoluminescent dosimeters in a 15 MV clinical photon beam in a liquid water phantom. Appl Radiat Isot 2012; 70:1360-2. [PMID: 22342311 DOI: 10.1016/j.apradiso.2012.01.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 01/31/2012] [Accepted: 01/31/2012] [Indexed: 10/14/2022]
Abstract
This paper compares the performance of CaSO4:Dy and LiF dosimeters irradiated with a 15 MV photon beam of a clinical linear accelerator to 0.1-10 Gy in a liquid water. The dose-response curves are linear up to 5 Gy. The average TL sensitivity of CaSO4:Dy is 26 and 287 times higher than the sensitivities of LiF:Mg,Ti and microLiF:Mg,Ti, respectively. CaSO4:Dy has an intrinsic efficiency 71% and 94% higher than the intrinsic efficiencies of LiF:Mg,Ti and microLiF:Mg,Ti, respectively.
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Affiliation(s)
- A Bravim
- Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN), Avenida Professor Lineu Prestes, 2242, Cidade Universitária, São Paulo, SP, Brazil
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Goncalves V, Lopes CP, Sakuraba RK, Cruz JC. SU-FF-T-237: To Evaluate the Intensity Modulated Split Field Using Proprietary Software. Med Phys 2009. [DOI: 10.1118/1.3181713] [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: 11/07/2022] Open
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15
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Goncalves V, Lopes CP, Sakuraba RK, Cruz JC. SU-FF-T-298: MLC Quality Control Evaluation Combining Dynalog Files and Portal Dosimetry Using Proprietary Software. Med Phys 2009. [DOI: 10.1118/1.3181775] [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: 11/07/2022] Open
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16
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Cruz JC, Bonagamba LGH, Machado BH, Biancardi VC, Stern JE. Intermittent activation of peripheral chemoreceptors in awake rats induces Fos expression in rostral ventrolateral medulla-projecting neurons in the paraventricular nucleus of the hypothalamus. Neuroscience 2008; 157:463-72. [PMID: 18838112 PMCID: PMC2700055 DOI: 10.1016/j.neuroscience.2008.08.070] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/20/2008] [Accepted: 08/22/2008] [Indexed: 11/21/2022]
Abstract
Despite the well-established sympathoexcitation evoked by chemoreflex activation, the specific sub-regions of the CNS underlying such sympathetic responses remain to be fully characterized. In the present study we examined the effects of intermittent chemoreflex activation in awake rats on Fos-immunoreactivity (Fos-ir) in various subnuclei of the paraventricular nucleus of the hypothalamus (PVN), as well as in identified neurosecretory preautonomic PVN neurons. In response to intermittent chemoreflex activation, a significant increase in the number of Fos-ir cells was found in autonomic-related PVN subnuclei, including the posterior parvocellular, ventromedial parvocellular and dorsal-cap, but not in the neurosecretory magnocellular-containing lateral magnocellular subnucleus. No changes in Fos-ir following chemoreflex activation were observed in the anterior PVN subnucleus. Experiments combining Fos immunohistochemistry and neuronal tract tracing techniques showed a significant increase in Fos-ir in rostral ventrolateral medulla (RVLM)-projecting (PVN-RVLM), but not in nucleus of solitarii tract (NTS)-projecting PVN neurons. In summary, our results support the involvement of the PVN in the central neuronal circuitry activated in response to chemoreflex activation, and indicate that PVN-RVLM neurons constitute a neuronal substrate contributing to the sympathoexcitatory component of the chemoreflex.
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Affiliation(s)
- J C Cruz
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil
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Weltman E, Salvajoli JV, Brandt RA, de Morais Hanriot R, Prisco FE, Cruz JC, de Oliveira Borges S, Lagatta M, Ballas Wajsbrot D. Radiosurgery for brain metastases: who may not benefit? Int J Radiat Oncol Biol Phys 2001; 51:1320-7. [PMID: 11728693 DOI: 10.1016/s0360-3016(01)01696-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE To select a group of patients with brain metastases for whom stereotactic radiosurgery (SRS) may not be beneficial. PATIENTS, MATERIALS, AND METHODS Actuarial survival of 87 patients with brain metastases treated with SRS between July 1993 and May 1999 was retrospectively analyzed under stratification by the Score Index for Stereotactic Radiosurgery for Brain Metastases (SIR). To identify the group of patients most likely to survive less than 6 months after SRS, Cox model survival curves were calculated for all SIR values, and Kaplan-Meier survival curves were calculated for two SIR subsets (0-5 and 6-10) and were compared by log-rank test. RESULTS Overall median survival after SRS was 6.88 months. The stratification of patients into two SIR subsets (0-5 and 6-10) sustained statistical significance regarding survival with p = 0.0001. The median survival time for the group of patients with SIR between 0 and 5 was 4.52 months (95% confidence interval of 2.82 to 5.84 months). Survival probability at 6 months for this group of patients with poor prognosis was 35.6%. CONCLUSION Patients with brain metastases and SIR of 5 or lower have an expected median survival of less than 6 months after treatment with radiosurgery. Thus, radiosurgery may not be beneficial for this group of patients.
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Affiliation(s)
- E Weltman
- Department of Radiation Oncology, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
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Brito FS, Hanriot R, Almeida BO, Rati MA, Medeiros NS, Lagatta M, Cruz JC, Salvajoli JV, Perin MA. Intracoronary brachytherapy in the treatment of in-stent restenosis. Initial experience in Brazil. Arq Bras Cardiol 2001; 77:266-73. [PMID: 11562689 DOI: 10.1590/s0066-782x2001000900007] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intracoronary brachytherapy using beta or gamma radiation is currently the most efficient type of therapy for preventing the recurrence of coronary in-stent restenosis. Its implementation depends on the interaction among interventionists, radiotherapists, and physicists to assure the safety and quality of the method. The authors report the pioneering experience in Brazil of the treatment of 2 patients with coronary in-stent restenosis, in whom beta radiation was used as part of the international multicenter randomized PREVENT study (Proliferation REduction with Vascular ENergy Trial). The procedures were performed rapidly and did not require significant modifications in the traditional techniques used for conventional angioplasty. Alteration in the radiological protection devices of the hemodynamic laboratory were also not required, showing that intracoronary brachytherapy using beta radiation can be incorporated into the interventional tools of cardiology in our environment.
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Affiliation(s)
- F S Brito
- Hospital Israelita Albert Einstein, São Paulo, Brazil.
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Abstract
To model the normalized phase III slope (Sn) from N2 expirograms of the multibreath N2 washout is a challenge to researchers. Experimental measurements show that Sn increases with the number of breaths. Previously, we predicted Sn by setting the concentration (atm) of mixed venous blood (Fbi,N2) to a constant value of 0.3 after the fifth breath to calculate the amount of N2 transferred from the blood to the alveoli. As a consequence, the predicted curve of the Sn values showed a maximum before the quasi-steady state was reached. In this paper, we present a way of calculating the amount of N2 transferred from the blood to the alveoli by setting Fbi,N2 in the following way: In the first six breaths Fbi,N2 is kept constant at the initial value of 0.8 because circulation time needs at least 30 s to alter it. Thereafter, a single exponential function with respect the number of breaths is used: Fbi = 0.8 exp[0.112(6-n)], in which n is the breath number. The predicted Sn values were compared with experimental data from the literature. The assumption of an exponential decay in the N2 evolved from mixed venous blood is important in determining the shape of the Sn curve but new experimental data are needed to determine the validity of the model. We concluded that this new approach to calculate the N2 evolution from the blood is more meaningful physiologically.
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Affiliation(s)
- D Han
- Department of Mechanical Engineering, The University of Toledo, OH, USA
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Cruz JC, Alsina M, Craig F, Yoneda T, Anderson JL, Dallas M, Roodman GD. Ibandronate decreases bone disease development and osteoclast stimulatory activity in an in vivo model of human myeloma. Exp Hematol 2001; 29:441-7. [PMID: 11301184 DOI: 10.1016/s0301-472x(01)00618-x] [Citation(s) in RCA: 33] [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: 10/18/2022]
Abstract
The benefits of bisphosphonate therapy for multiple myeloma bone disease have been clearly documented. However, the effects of bisphosphonates on the osteoclast stimulatory activity (OSA) that is present in the marrow of patients with multiple myeloma, even before the bone disease is detectable, are unknown. Therefore, we examined the effects of ibandronate (IB) treatment prior to the development of bone disease in a murine model of human myeloma. Sublethally irradiated severe combined immunodeficient (SCID) mice were transplanted with ARH-77 cells on day 0. These ARH-77 mice were treated daily with subcutaneous injections of IB started before or at different times after tumor injection as follows: group 1 was started on day -7; group 2 on day 0; group 3 on day +7; group 4 on day +14 after IB administration; and group 5 (control) received no IB. Mice were sacrificed after they developed paraplegia. The onset of paraplegia was delayed in group 1 vs all other groups (mean day 27 vs day 32; p = 0.0098). The number of lytic lesions and the bone surface area of resorption (mm(2)) were significantly decreased in groups 1, 2, and 3, which were treated early with IB, when compared with groups 4 and 5 (p = 0.003 and 0.002, respectively). OSA, as measured by the capacity of bone marrow plasma from ARH-77 mice to induce osteoclast (OCL) formation in human bone marrow cultures, was decreased proportionally to the length of IB treatment. Group 1 had the lowest OSA compared with the other groups (p = 0.003). However, all mice eventually developed paraplegia, and at time of sacrifice, tumor burden was not grossly different among the groups. Interestingly, macroscopic abdominal tumors were more frequent in mice treated with IB. These data demonstrate that early treatment of ARH-77 mice with IB prior to development of myeloma bone disease decreases OSA and possibly retards the development of lytic lesions, but not eventual tumor burden.
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Affiliation(s)
- J C Cruz
- Department of Medicine, Texas Tech University, Lubbock, TX, USA
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Abstract
Mammalian cells obtain cholesterol via two pathways: endogenous synthesis in the endoplasmic reticulum and exogenous sources mainly through the low density lipoprotein (LDL) receptor pathway. We performed pulse-chase experiments to monitor the fate of endogenously synthesized cholesterol and showed that, after reaching the plasma membrane from the endoplasmic reticulum, the newly synthesized cholesterol eventually accumulates in an internal compartment in Niemann-Pick type C1 (NPC1) cells. Thus, the ultimate fate of endogenously synthesized cholesterol in NPC1 cells is the same as LDL-derived cholesterol. However, the time required for endogenous cholesterol to accumulate internally is much slower than LDL-derived cholesterol. Different pathways thus govern the post-plasma membrane trafficking of endogenous cholesterol and LDL-derived cholesterol to the internal compartment. Results using the inhibitor N-butyldeoxynojirimycin, which depletes cellular complex glycosphingolipids, demonstrates that the cholesterol trafficking defect in NPC1 cells is not caused by ganglioside accumulation. The ultimate cause of death in NPC disease is progressive neurological deterioration in the central nervous system, where the major source of cholesterol is derived from endogenous synthesis. Our current study provides a plausible link between defects in intracellular trafficking of endogenous cholesterol and the etiology of Niemann-Pick type C disease.
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Affiliation(s)
- J C Cruz
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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Abstract
Coagulation abnormalities and bleeding disorders are frequently encountered in patients undergoing invasive procedures. These are of particular importance in the pain management setting where even small amounts of excessive bleeding can result in devastating complications. It is imperative that physicians treating those patients under-stand the basic concepts of coagulation and be able to identify and manage the common bleeding disorders. This article provides a brief overview of the coagulation system and describes the use of appropriate screening tests and management strategies to limit bleeding in pain management procedures.
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Affiliation(s)
- E Cobos
- Texas Tech University Health Sciences Center, Departments of Medicine and Anesthesia, 3601 4th Street, Room 1C282, Lubbock, TX 79430, USA
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Choi SJ, Cruz JC, Craig F, Chung H, Devlin RD, Roodman GD, Alsina M. Macrophage inflammatory protein 1-alpha is a potential osteoclast stimulatory factor in multiple myeloma. Blood 2000; 96:671-5. [PMID: 10887133] [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: 02/17/2023] Open
Abstract
This study was designed to determine if macrophage inhibitory protein-1 alpha (MIP-1 alpha), a recently described osteoclast (OCL) stimulatory factor,(1) was present in marrow from patients with multiple myeloma (MM) and possibly involved in the bone destructive process. MIP-1 alpha, but not interleukin-1 beta (IL-1 beta), tumor necrosis factor-beta (TNF-beta), or interleukin-6 (IL-6), messenger RNA was elevated in freshly isolated bone marrow from 3 of 4 patients with MM compared to normal controls. Furthermore, enzyme-linked immunosorbent assays of freshly isolated bone marrow plasma detected increased concentrations of hMIP-1 alpha (range, 75-7784 pg/mL) in 8 of 13 patients (62%) with active myeloma, in 3 of 18 patients (17%) with stable myeloma (range, 75-190.3), as well as in conditioned media from 4 of 5 lymphoblastoid cell lines (LCLs) derived from patients with MM. Mildly elevated levels of MIP-1 alpha were detected in 3 of 14 patients (21%) with other hematologic diagnoses (range, 80.2-118.3, median value of 96 pg/mL) but not in normal controls (0 of 7). MIP-1 alpha was not detected in the peripheral blood of any patients with MM. In addition, recombinant hMIP-1 alpha induced OCL formation in human bone marrow cultures. Importantly, addition of a neutralizing antibody to MIP-1 alpha to human bone marrow cultures treated with freshly isolated marrow plasma from patients with MM blocked the increased OCL formation induced by these marrow samples but had no effect on control levels of OCL formation. Thus, high levels of MIP-1 alpha are expressed in marrow samples from patients with MM, but not in marrow from patients with other hematologic disorders or controls, and support an important role for MIP-1 alpha as one of the major factors responsible for the increased OCL stimulatory activity in patients with active MM. (Blood. 2000;96:671-675)
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Affiliation(s)
- S J Choi
- Departments of Medicine/Hematology and Pathology, University of Texas Health Science Center, San Antonio, TX, USA. Center a
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Jeng DR, Wu G, Cruz JC, Han D, Flores XF. Diffusion-convection equation solved in parallel regions of the lung. Ann Biomed Eng 2000; 28:453-62. [PMID: 10870902 DOI: 10.1114/1.283] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The single path model of airway gas transport was incorporated into each of Cruz (Cruz, J. C. Respir. Physiol. 86:1-14, 1991). Thus, the effect of time on the predicted gas fractions in and out of the lung could be evaluated. Two experimental maneuvers were simulated: (1) fast inhalation of an argon-oxygen mixture from a functional residual capacity and fast exhalation to residual volume, including inspiratory breath holdings of 5-20 s, and (2) the standard single-breath nitrogen washout test. Expired argon and nitrogen are predicted within a +3% error of the experimental data with no breath holding. Breath holding predictions were at variance with experimental results because the solution of the diffusion-convection equation produced even mixing in the alveoli at the end of inspiration. The minimum square of the difference between the experimental data (standard single-breath nitrogen washout test) and those provided by the model was 0.0016. This model is capable of generating a nitrogen expirogram with four phases when a vital capacity of oxygen is inhaled. However, the model failed to produce a sharp distinction between phase 3 and phase 4. Thus, we conclude that uneven emptying of parallel regions generates any expirogram (a fast or slow expiratory maneuver). The alveolar gas stratification that is created during inspiration disappears at the end of the inspiratory maneuver. As a result, breath holding maneuvers cannot be predicted in the anatomical model used.
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Affiliation(s)
- D R Jeng
- Department of Mechanical Engineering, The University of Toledo, OH, USA
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Weltman E, Salvajoli JV, Brandt RA, de Morais Hanriot R, Prisco FE, Cruz JC, de Oliveira Borges SR, Wajsbrot DB. Radiosurgery for brain metastases: a score index for predicting prognosis. Int J Radiat Oncol Biol Phys 2000; 46:1155-61. [PMID: 10725626 DOI: 10.1016/s0360-3016(99)00549-0] [Citation(s) in RCA: 277] [Impact Index Per Article: 11.5] [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: 10/18/2022]
Abstract
PURPOSE To analyze a prognostic score index for patients with brain metastases submitted to stereotactic radiosurgery (the Score Index for Radiosurgery in Brain Metastases [SIR]). METHODS AND MATERIALS Actuarial survival of 65 brain metastases patients treated with radiosurgery between July 1993 and December 1997 was retrospectively analyzed. Prognostic factors included age, Karnofsky performance status (KPS), extracranial disease status, number of brain lesions, largest brain lesion volume, lesions site, and receiving or not whole brain irradiation. The SIR was obtained through summation of the previously noted first five prognostic factors. Kaplan-Meier actuarial survival curves for all prognostic factors, SIR, and recursive partitioning analysis (RPA) (RTOG prognostic score) were calculated. Survival curves of subsets were compared by log-rank test. Application of the Cox model was utilized to identify any correlation between prognostic factors, prognostic scores, and survival. RESULTS Median overall survival from radiosurgery was 6.8 months. Utilizing univariate analysis, extracranial disease status, KPS, number of brain lesions, largest brain lesion volume, RPA, and SIR were significantly correlated with prognosis. Median survival for the RPA classes 1, 2, and 3 was 20.19 months, 7.75 months, and 3. 38 months respectively (p = 0.0131). Median survival for patients, grouped under SIR from 1 to 3, 4 to 7, and 8 to 10, was 2.91 months, 7.00 months, and 31.38 months respectively (p = 0.0001). Using the Cox model, extracranial disease status and KPS demonstrated significant correlation with prognosis (p = 0.0001 and 0.0004 respectively). Multivariate analysis also demonstrated significance for SIR and RPA when tested individually (p = 0.0001 and 0.0040 respectively). Applying the Cox Model to both SIR and RPA, only SIR reached independent significance (p = 0.0004). CONCLUSIONS Systemic disease status, KPS, SIR, and RPA are reliable prognostic factors for patients with brain metastases submitted to radiosurgery. Applying SIR and RPA classifications to our patients' data, SIR demonstrated better accuracy in predicting prognosis. SIR should be further tested with larger patient accrual and for all patients with brain metastases subjected or not to stereotactic radiosurgery.
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Affiliation(s)
- E Weltman
- Department of Radiation Oncology, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
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Cruz JC, Sugii S, Yu C, Chang TY. Role of Niemann-Pick type C1 protein in intracellular trafficking of low density lipoprotein-derived cholesterol. J Biol Chem 2000; 275:4013-21. [PMID: 10660558 DOI: 10.1074/jbc.275.6.4013] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [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: 11/06/2022] Open
Abstract
Niemann-Pick type C (NPC) is a disease that affects intracellular cholesterol-trafficking pathways. By cloning the hamster ortholog of NPC1, we identified the molecular lesions in two independently isolated Chinese hamster ovary cell mutants, CT60 and CT43. Both mutants lead to premature translational terminations of the NPC1 protein. Transfecting hamster NPC1 cDNA complemented the defects of the mutants. Investigation of the CT mutants, their parental cells, and an NPC1-stable transfectant allow us to present evidence that NPC1 is involved in a post-plasma membrane cholesterol-trafficking pathway. We found that the initial movement of low density lipoprotein (LDL)-derived cholesterol to the plasma membrane (PM) did not require NPC1. After reaching the PM and subsequent internalization, however, cholesterol trafficking back to the PM did involve NPC1. Both LDL-derived cholesterol and cholesterol originating from the PM accumulated in a dense, intracellular compartment in the CT mutants. Cholesterol movement from this compartment to the PM or endoplasmic reticulum was defective in the CT mutants. Our results functionally distinguish the dense, intracellular compartment from the early endocytic hydrolytic organelle and imply that NPC1 is involved in sorting cholesterol from the intracellular compartment back to the PM or to the endoplasmic reticulum.
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Affiliation(s)
- J C Cruz
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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de Almeida CE, Pereira AJ, Marechal MH, Pereira G, Cruz JC, Ferraz JC, Giordani AJ, Khalil CM, Martins RH, Menegussi G, Moreira D, Rocha JR, Pinto MA. Intercomparison of calibration procedures for 192Ir HDR sources in Brazil. Phys Med Biol 1999; 44:N31-8. [PMID: 10211813 DOI: 10.1088/0031-9155/44/3/006] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The lack of well established dosimetry protocols for HDR sources is a point of great concern regarding the uniformity of procedures within a particular country and worldwide. The main objective of this paper is to report the results from ten institutions of an intercomparison of calibration procedures for 192Ir HDR sources currently in use in Brazil. The treatment irradiator of one institution was calibrated by a reference system and used by all participants with their own measuring electrometers and ionization chambers under the same experimental conditions. Two methods were used: the calibration jig and the well-type ionization chamber. Each participant was allowed to use their own method and formalism. The results of this exercise were very positive since this was the first time in Brazil that a group of users gathered to share their experience and openly discuss the physical concepts behind the calibration procedures. The results were all within +/-3.0%, except one case where -4.6% was observed and later identified as a problem with the Nk value for x-rays. Though the magnitude of the deviations found was generally acceptable considering the diversity of formalisms currently in use, a proposal is now being prepared to be adopted as a national protocol. The identification of the institutions was left out for the sake of confidentiality.
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Affiliation(s)
- C E de Almeida
- Laboratório de Ciências Radiológicas-LCR-DBB-UERJ, Rio de Janeiro, Brazil.
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Chang CC, Lee CY, Chang ET, Cruz JC, Levesque MC, Chang TY. Recombinant acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) purified to essential homogeneity utilizes cholesterol in mixed micelles or in vesicles in a highly cooperative manner. J Biol Chem 1998; 273:35132-41. [PMID: 9857049 DOI: 10.1074/jbc.273.52.35132] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [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: 11/06/2022] Open
Abstract
Acyl-coenzyme A:cholesterol acyltransferase (ACAT) is an integral membrane protein located in the endoplasmic reticulum. It catalyzes the formation of cholesteryl esters from cholesterol and long-chain fatty acyl coenzyme A. The first gene encoding the enzyme, designated as ACAT-1, was identified in 1993 through an expression cloning approach. We isolated a Chinese hamster ovary cell line that stably expresses the recombinant human ACAT-1 protein bearing an N-terminal hexahistidine tag. We purified this enzyme approximately 7000-fold from crude cell extracts by first solubilizing the cell membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, then proceeding with an ACAT-1 monoclonal antibody affinity column and an immobilized metal affinity column. The final preparation is enzymologically active and migrates as a single band at 54 kDa on SDS-polyacrylamide gel electrophoresis. Pure ACAT-1 dispersed in mixed micelles containing sodium taurocholate, phosphatidylcholine, and cholesterol remains catalytically active. The cholesterol substrate saturation curves of the enzyme assayed either in mixed micelles or in reconstituted vesicles are both highly sigmoidal. The oleoyl-coenzyme A substrate saturation curves of the enzyme assayed under the same conditions are both hyperbolic. These results support the hypothesis that ACAT is an allosteric enzyme regulated by cholesterol.
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Affiliation(s)
- C C Chang
- Dartmouth Medical School, Department of Biochemistry, Hanover, New Hampshire 03755, USA.
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Abstract
The single path model of airway gas transport, with and without a distributed blood source term, was used to simulate multiple-breath N2 washout by breathing pure O2 in two lung models: a single-region lung model (SRLM) which produces series inhomogeneity, and a seven-region lung model (7RLM) incorporating both series and parallel inhomogeneities. Normalized phase III slopes (Sn) from N2 expirograms were computed for each breath and compared with published human experimental data obtained under similar conditions. The 7RLM predicts well the trend of experimental Sn N2 changes and is superior to the SRLM in the first part (the unsteady state), implying that this part of the curve is mostly due to convective mixing of the seven parallel flow streams. In the quasi-steady state, the 7RLM is not obviously superior to the SRLM. Functional residual capacity and pulmonary perfusion are shown to strongly affect the number of breaths required to reach the quasi-steady state. The anatomical dimensions that appear to be critical in SRLM are not as important in the 7RLM.
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Affiliation(s)
- J C Cruz
- Department of Anesthesiology, Medical College of Ohio, Toledo 43699. USA
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Cruz H, Cruz JC, Badui E, Galindo ME, Solorio S, Bojorges R. [Cardiac rupture in acute myocardial infarct. Presentation of 20 postmortem cases]. Arch Inst Cardiol Mex 1997; 67:51-8. [PMID: 9221710] [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: 02/04/2023]
Abstract
With the advancement of the Coronary Care Units in the past three decades, there had been an important reduction in mortality secondary to arrhythmias in acute myocardial infarction (AMI): been now days, cardiogenic shock and cardiac rupture the first and second causes of in-hospital death in these patients. The purpose of this report is to know the anatomoclinical characteristics in our hospital of cardiac rupture and to look for risk factors that may be considered to diagnose at the precise time this complication that might cause sudden death secondary to hemodynamic and electromechanical changes. From 300 postmortem cases with AMI proved clinical, and by anatomopathological studies, 20 cases with cardiac rupture were obtained, among which: 11 (55%) were males with an average age of 61.7 years and 9 (45%) females, with an average age of 60 years. The following coronary risk factors were detected: systemic hypertension in 15 (75%) cases; cigarette smoking in 13 (65%) cases and diabetes mellitus in 11 (55%) cases. Long lasting or recurrent history of chest pain previous to death was present in 14 (70%) cases. Conduction disturbances were detected in 13 (65%) cases; among them, 7 (35%) had third degree heart block in whom permanent pacemaker was inserted; 4 (20%) had CRBBB and 2 (10%) ASB. The average heart weight was 478 gr. in males and 434 gr. in females. Evidence of an old MI was present in 7 (35%) cases. All patients had transmural MI. Free cardiac wall rupture was seen in 14 (70%) cases and from the ventricular septum, 6 (30%) cases. Hemopericardium was present in all cases (100%) with an average amount of 425 ml of blood. Pericarditis in 3 (15%). The average time of evolution since the beginning of the AMI until death were 4 days and the main causes of death were cardiogenic shock in 17 (85%) and congestive heart failure in 3 (15%).
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Affiliation(s)
- H Cruz
- Del Hospital de Especialidades, Centro Médico La Raza, México, D.F
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Abstract
RATIONALE AND OBJECTIVES The scheduling of radiology residents remains a major annual undertaking of chief residents. In this article, we describe a paradigm to implement interactive computer programs to reduce the inefficiencies and inequities of planning the yearly schedule. METHODS We used the programming language, Prolog, to develop a compact program that provides faster and more flexible performance than those reported in the literature. This interactive program stores scheduling requirements in data files separated from the control program and runs on a Macintosh computer. RESULTS The schedule of any residency year is generated within 3-7 sec. The fast computation and query capabilities of this scheduling program have helped chief residents to identify conflicting requirements that were previously overlooked. CONCLUSION Using our programming paradigm, we have developed a portable Prolog-based scheduling program that is quick and easy to use.
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Affiliation(s)
- S T Wong
- Department of Radiology, University of California, San Francisco 94143-0628, USA
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Flores XF, Cruz JC. Single-breath, room-air method for measuring closing volume (phase 4) in the normal human lung. Chest 1992; 102:438-43. [PMID: 1643929 DOI: 10.1378/chest.102.2.438] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The purpose of this study was to evaluate a new method to measure closing volume (CV). This new method does not require oxygen or inert gases to be inhaled to obtain the onset of phase 4. Because there are regional differences in the concentrations of the resident alveolar gases (O2, CO2, and N2), there should be an abrupt change in the concentration of these gases at the terminal portion of a prolonged expired vital capacity (VC) that marks the onset of phase 4. Nine normal healthy subjects, 30 to 65 years of age, inspired room air from residual volume (to mimic the maneuver of the standard single breath N2 (SBN2) washout test) to total lung capacity. During the expiration (flow constant at 250 ml.s-1) following a 10-s breath hold at total lung capacity, the exhaled gas was analyzed with a mass spectrometer for fractions of O2, CO2, and N2. Although the onset of phase 4 can be shown as the change in concentration of any of the three alveolar resident gases, oxygen was selected because (1) it demonstrates a greater apex to base concentration gradient than that found with CO2 and N2, and (2) a clear identification of the onset of phase 4 (minimum value of O2 fraction). With this method, the mean +/- SEM of CV was 16.8 +/- 1.52 percent (CV x 100/VC). No significant difference was found among the room air method, SBN2 method, and the helium bolus technique.
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Affiliation(s)
- X F Flores
- Department of Physiology, Medical College of Ohio, Toledo
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Abstract
The distribution within the lungs of inspired gas has been demonstrated to be uneven by the technique of the external counting of inspired radioactive gas (Milic-Emili et al. (1966) J. Appl. Physiol. 21: 749-759). The contribution of this regional distribution to the slope of the alveolar plateau observed at the lips from an inspired gas marker has been debated, particularly the part played by incomplete diffusive mixing (Sikand et al. (1966) J. Appl. Physiol. 21: 1331-1337). We have repeated the experiments of Sikand, obtaining similar results, by inspiring 1.9 L of 79% argon and 21% oxygen from functional residual capacity, with a subsequent expiration to residual volume, after various breath-holding times. The opposing views of the above authors (parallel versus series inhomogeneities) are here used to develop a model in which the lung is divided into seven regions from apex to base, each region being allocated a compliance curve (polynomial equation of third order) after that of Milic-Emili. Each model region then receives a volume of inspired gas according to its compliance and its regional dead space. This dead space has been allocated on the basis of increasing path lengths of inspired gas from the apex to the base. Beyond the front of this dead space, the mixing of gas is taken to be exponential with respect to expired volume and a curve is then allocated to this alveolar region. The model thus contains both parallel (inter-regional) and series (intra-regional) components. Following a simulated expiration of these seven regions, the model expired curve so obtained is in close agreement with the experimental data, both in respect of shape and of the quantity of tracer contained within it in the range of 0.75-4.5 L of expired gas. We therefore conclude that inter-regional factors are the principal determinant of the last 2.5 L of the expired gas tracer curve and that intra-regional components play a significant role in the first 1.25 L. The model is also applicable to any other inhaled inert gas.
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Affiliation(s)
- J C Cruz
- Abteilung Physiologie, Max-Planck-Institut für experimentelle Medizin, Göttingen, Germany
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Cruz JC, Metting PJ. Correct application of the shunt fraction calculation. Anesth Analg 1991; 72:127-8. [PMID: 1984369 DOI: 10.1213/00000539-199101000-00024] [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: 12/29/2022]
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Cruz JC. What is the meaning of the expired CO2 waveform? Anesth Analg 1990; 70:675-6. [PMID: 2111644 DOI: 10.1213/00000539-199006000-00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
The pulmonary shunt fraction (Qs/Qt) is frequently calculated in critically ill patients to monitor the effectiveness of pulmonary oxygenation. The breathing of pure oxygen often results in higher calculated Qs/Qt values that have been attributed to the development of atelectasis, ventilation-perfusion imbalance, or both. To interpret properly the changes in calculated Qs/Qt that occur when the inspired oxygen fraction is altered, the changes produced in all the variables affecting Qs/Qt must be known. This tutorial presents an in-depth analysis of the four variables affecting the calculation of Qs/Qt: VO2 (oxygen uptake), Qt (cardiac output), Cc'O2 (oxygen content in pulmonary end capillaries), and CvO2 (oxygen content in mixed venous blood). These variables are related according to the following equation, which is derived by combining the Fick and the classic shunt equations: Qs/Qt = 1 - [(VO2/Qt)/(Cc'O2 - CvO2)]. Three-dimensional surface representations relating these variables are also presented to help the reader understand the effects of these variables on the calculated Qs/Qt.
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Cruz JC. Reducing the cost of using neuromuscular relaxants. Anesth Analg 1986; 65:315-6. [PMID: 3954101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Cruz JC, Reeves JT, Russell BE, Alexander AF, Will DH. Embryo transplanted calves: the pulmonary hypertensive trait is genetically transmitted. Proc Soc Exp Biol Med 1980; 164:142-5. [PMID: 7393919 DOI: 10.3181/00379727-164-40837] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Cruz JC, Reeves JT, Grover RF, Maher JT, McCullough RE, Cymerman A, Denniston JC. Ventilatory acclimatization to high altitude is prevented by CO2 breathing. Respiration 1980; 39:121-30. [PMID: 6773122 DOI: 10.1159/000194206] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The hypoxia of high altitude stimulates ventilation. If the resultant respiratory alkalosis inhibits the initial increase in ventilation, then with prevention of alkalosis, ventilation should rise immediately to a stable plateau. 4 subjects inspired CO2 (3.77%) from ambient air in a hypobaric chamber (PB = 440-455 Torr) during 100 h at high altitude. Ventilation (for given oxygen uptakes at rest and during exercise) increased promptly and remained stable. 4 control subjects exposed to high altitude without CO2 supplementation showed the expected progressive increases in ventilation with time. The hyperoxic CO2 ventilatory response curve shifted progressively to the left with time in the control subjects, but not in those given supplemental CO2. The latter group also failed to increase the ventilatory response to isocapnic hypoxia. Thus, CO2 supplementation at high altitude prevented the so-called "ventilatory acclimatization' from occurring. Prevention of respiratory alkalosis at high altitude probably permitted maintenance of [H+] at some central nervous system locus, thus allowing an uninhibited hypoxic stimulation of ventilation.
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Abstract
There is not unanimous agreement in the literature regarding the effects of bleeding on pulmonary gas exchange in polycythemic patients. Spirometry, alveolar arterial O2 and CO2 tension differences, PaO2 breathing 100% oxygen and carbon monoxide-diffusing capacity were measured before and after 1 week of chronic phlebotomy in 4 chronic mountain polycythemic patients. Studies were carried out at 3,700 m above sea level (PB = 491 mm Hg). Before phlebotomy, 2 patients showed abnormal spirometry and gas exchange. Only 1 patient had high PaCO2 and all of them showed low values of PaO2 breathing oxygen. Phlebotomy improved both spirometry and gas exchange. Improvement in arterial oxygen saturation and PaO2 could not be attributed to changes in alveolar ventilation, but rather to better distribution of VA/Qc ratios since physiological dead space decreased. Our results are similar to those reported in polycythemia vera patients. A significant correlation between the changes in PaO2 with phlebotomy and the control PaO2 have been found from 45 polycythemic patients with chronic obstructive pulmonary disease collected from the literature. It is concluded that excessive polycythemia worsened hypoxemia and that phlebotomy improved gas exchange.
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Cymerman A, Maher JT, Cruz JC, Reeves JT, Denniston JC, Grover RF. Increased 2,3-diphosphoglycerate during normocapnic hypobaric hypoxia. Aviat Space Environ Med 1976; 47:1069-72. [PMID: 985279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The effect of 96 h of exposure to hypobaric hypoxia with and without 3.8% CO2 supplementation was studied in two groups of subjects. Five subjects (CO2) were exposed to 440-465 mm Hg barometric pressure (4000-4400 m), and 4 subjects (no-CO2) were exposed to 455-492 mm Hg (3500-1400 m) in order to produce similar levels of resting end-tidal PO2. After 24 h, 2,3-DPG levels of both groups significantly increased and remained elevated. The CO2 group had higher levels than the non-CO2 group after 48 and 72 h. Concurrent measurements of P50 showed similar changes over the same time course. Mean corpuscular hemoglobin concentrations remained normal for 48 h and then decreased in both groups, the CO2 group showing the larger decrease. We conclude that altitude exposure may produce an increase in 2,3-DPG without the presence of respiratory alkalosis previously thought necessary.
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Grover RF, Reeves JT, Maher JT, McCullough RE, Cruz JC, Denniston JC, Cymerman A. Maintained stroke volume but impaired arterial oxygenation in man at high altitude with supplemental CO2. Circ Res 1976; 38:391-6. [PMID: 1269078 DOI: 10.1161/01.res.38.5.391] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hypobaric hypoxia causes hypocapina and alkalosis, hemoconcentration and increased hematocrit, and a decreased cardiac stroke volume. To assess the role of the hypocapnic alkalosis in causing these other changes, five men were exposed to hypobaric hypoxia at a barometric pressure (PB) of 440 torr with an alveolar O2 tension of 55 torr for 5 days with 3.77% CO2 added to the atmosphere to prevent alkalosis. They did not lose weight, and arterial CO2 tension, pH, and cardiac stroke volume were unchanged. An unchanged hematocrit implied an unchanged plasma volume. During exercise to maximum, stroke volumes equaled sea level values but arterial hypoxemia was profound, the arterial O2 tension being 39 torr. By contrast, three men at high altitude without CO2 supplementation (PB=455 torr; alveolar PO2=56 torr) had weight loss, hypocapnia, alkalosis, and decreased stroke volume. Increased hematocrits suggested decreased plasma volumes. During exercise, arterial PO2 (48 torr) was higher than in the group receiving CO2. Maximum oxygen uptakes were decreased to a similar degree in the two groups. Catecholamine excretion doubled in the group with CO2 but in the group without CO2 catechoamine excretion was unchanged. A normal pH at high altitude apparently maintained plasma volume, which, with the increased catecholamine excretion, may have prevented a decrease in stroke volume. However, the subjects with CO2 added did not have enhanced oxygen transport, because their arterial oxygenation was impaired.
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Denniston JC, Maher JT, Reeves JT, Cruz JC, Cymerman A, Grover RF. Measurement of cardiac output by electrical impedance at rest and during exercise. J Appl Physiol (1985) 1976; 40:91-5. [PMID: 765317 DOI: 10.1152/jappl.1976.40.1.91] [Citation(s) in RCA: 171] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A comparison was made between cardiac output values determined by the dye dilution and electrical impedance methods in ten subjects at rest and during graded exercise on a bicycle ergometer. The cardiac output values determined by the two methods were linearly related and significantly (P less than 0.001) correlated (r = 0.90). Movement artifact associated with exercise at maximum or near-maximum work loads caused severe distortion of the dZ/dt wave form and prevented calculation of impedance cardiac output at these levels of work. Use of the lowest value of L (distance between mean value of L in the impedance stroke volume equation (SV = p(L2/ZO2) (dZ/dt)mt), resulted in nearly identical values for the least-squares line and equalvalue line of impedance and dye cardiac outputs. Although absolute values of cardiac output determined by the two methods were not identical in all subjects the changes in cardiac output were nearly identical during the different levels of exercise. The data support the validity of the impedance method as a noninvasive, atraumatic measure of cardiac output at rest and during graded exercise.
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Cruz JC, Grover RF, Reeves JT, Maher JT, Cymerman A, Denniston JC. Sustained venoconstriction in man supplemented with CO2 at high altitude. J Appl Physiol (1985) 1976; 40:96-100. [PMID: 1248989 DOI: 10.1152/jappl.1976.40.1.96] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Venoconstriction occurs at high altitude. This study sought to determine whether hypoxia or hypocapnia is the cause of the venoconstriction. Five male subjects were exposed to 4,000-4,400 m (PB 440-465 mmHg) with supplemental 3.77 +/- 0.02% CO2 in a hypobaric chamber for 4 days. Similar alveolar O2 tensions were obtained in four control subjects exposed to 3,500-4,100 m (PB 455-492 mmHg) without CO2. A water-filled plethysmograph was used to determine forearm flow and venous compliance. Systemic blood pressure was measured with the cuff procedure. Catecholamines were measured in 24-h urine collections. Venous compliance fell at high altitude in both groups and was less (P less than 0.01) than control values. Forearm flow and resistance were unaltered at altitude in the group with CO2 supplementation while forearm flow decreased and resistance increased in the hypocapnic group at 72 h of exposure. Urinary catecholamines increased in the group with CO2 and remained unaltered in the hypocapnic group. It is concluded that hypoxia is responsible for decreasing venous compliance, and hypocapnia for increasing resistance and decreasing flow. Group differences observed in urinary catecholamines may be explained by differences in arterial pH.
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Abstract
The supine pulmonary venous admixture (shunt) has been measured at Cerro de Pasco, 4,350 m altitude in eight subjects native to high altitude (HAN) under resting condition. Alveolar-arterial O2 tension difference (AaDO2) was also determined at rest and during exercise. The same subjects were studied again after 10 days' sojourn at sea level in Lima at 150 m altitude. They were compared with four subjects from sea level (SLN) who were studied first at Lima and after 2 and 10 days at Cerro de Pasco. At altitude, AaDO2 was smaller in HAN than SLN both at rest and during exercise. Shunt was the same in both groups. It is concluded that HAN show more even ventilation/perfusion relationship (VA/Q) at altitude, probably due to their high pulmonary artery pressure. On the contrary, SLN show less even VA/Q on altitude exposure, since their shunt decreased 37%. At sea level, HAN increased their AaDO2 due partially to an increase of 110% in their shunt, and in part due to less even VA/Q as shown by augmented VD/VT ratios. Each group tended to have a more effective gas exchange in its own environment.
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Maher JT, Cymerman A, Reeves JT, Cruz JC, Denniston JC, Grover RF. Acute mountain sickness: increased severity in eucapnic hypoxia. Aviat Space Environ Med 1975; 46:826-9. [PMID: 1156291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This study examined the hypothesis that prevention of hypocapnia and alkalosis would ameliorate the symptoms of acute mountain sickness (AMS). Five subjects were exposed to simulated high altitude for 4 d with 3.8% CO2 added to the chamber to maintain normocapnia. Four other subjects were exposed for 4 d to hypobaric hypoxia without CO2 supplementation, and became hypocapnic. Barometric pressure was lower in the group with added CO2 so that alveolar oxygen tensions (55-60 mm Hg) would not be different. The severity of symptoms was clearly greater in normocapnic than in hypocapnic subjects. Thus, prevention of hypocapnia did not alleviate AMS symptoms. The efficacy of CO2 addition in reducing symptoms, as reported by earlier workers, was probably the result of induced hyperventilation and partial relief of hypoxia. Indeed, in the present study with two comparably hypoxic groups, CO2 addition augmented the sysptoms, possibly by causing increased cerebral vasodiladation and spinal fluid pressure.
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Vogel JA, Hartley LH, Cruz JC, Hogan RP. Cardiac output during exercise in sea-level residents at sea level and high altitude. J Appl Physiol (1985) 1974; 36:169-72. [PMID: 4590352 DOI: 10.1152/jappl.1974.36.2.169] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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