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Myron S. Cohen

Bio: Myron S. Cohen is an academic researcher from University of North Carolina at Chapel Hill. The author has contributed to research in topics: Population & Acquired immunodeficiency syndrome (AIDS). The author has an hindex of 103, co-authored 549 publications receiving 46021 citations. Previous affiliations of Myron S. Cohen include University of Massachusetts Medical School & Scripps Health.


Papers
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Journal ArticleDOI
TL;DR: Interestingly, the potency of 19/10–25OHD3 was highest in the receptor‐mediated response (1:50) and lower in the other parameters, ranging from 1: 100 to 1:600 compared to 1,25(OH)2D3.
Abstract: 19 nor, 10 keto, 25-hydroxyvitamin D3 (19/10–25OHD3) is a metabolite of 25-OHD3 produced in vitro by various phagocytes including normal human blood monocytes and transformed cell lines, U937 and HL-60. We recently reported that 19/10–25OHD3 induced differentiation of U937 cells. In these studies, 19/10–25OHD3 alone produced no detectable effect on the growth rates, surface adherence, and oxidative metabolism of U937 and HL-60 cells. When combined with lymphocyte-conditioned medium (LCM), 19/10–25OHD3 reduced proliferation, increased surface adherence and stimulated luminol-dependent luminescence (LDL) of the U937 cells. In contrast, the combination of 19/10–25OHD3 and LCM had no effect on the growth of HL-60 cells but did increase the surface adherence and the expression of a complement receptor component. 19/10–25OHD3 competed for tritium-labeled 1,25(OH)2D3 binding to receptors extracted from cultured human skin fibroblasts. This displacement capacity was 600 times weaker than that of unlabeled 1,25(OH)2D3. Incubation of human skin fibroblasts for 24 hr with 19/10–25OHD3 induced 25OHD3-24-hydroxylase activity in the fibroblasts. The inductive potency of 19/10–25OHD3 was 1/50 that of 1,25(OH)2D3. These results demonstrate bioactivity of 19/10–25OHD3 in several systems. At least one of these responses, the induction of 25OHD3-24-hydroxylase, is a receptor-mediated event. Some of the other responses may be independent of the cellular receptor for 1,25(OH)2D3. Interestingly, the potency of 19/10–25OHD3 was highest in the receptor-mediated response (1:50) and lower in the other parameters, ranging from 1: 100 to 1:600 compared to 1,25(OH)2D3. This range of bioactivity in phagocytes and fibroblasts is presently unexplained.

4 citations

Journal ArticleDOI
TL;DR: It is indicated that E can modulate the differentiation of phagocytes indirectly by altering the synthesis and/or secretion of lymphokines through the inhibition of LCM-E.
Abstract: The effect of 17β-estradiol (E) on the oxidative metabolism of U937 cells was studied. E had no direct effect on the proliferation, surface adherence, or luminol-enhanced luminescence (LEL) of the U937 cells. Exposure of U937 cells to lymphocyte-conditioned medium (LCM) and 1,25-dihydroxyvitamin D3 allowed a maximal LEL response by cells stimulated with phorbol myristate acetate. In contrast, LCM from lymphocytes exposed to E (LCM-E) did not stimulate LEL to the same extent as did an equal volume of LCM. Increasing the E concentration in the lymphocyte medium was associated with a dosedependent reduction in the LEL response of the U937 cells. Mixing equal quantities of LCM and LCM-E significantly decreased LEL levels. LEL stimulated by LCM, γ-interferon, or differentiation-inducing factor was reduced by the presence of LCM-E. The inhibitory action of LCM-E was reversible and metabolite specific. 17α-E produced an effect that was only one tenth the magnitude of the E effect. These findings indicate that E ...

4 citations

Journal ArticleDOI
TL;DR: Difficulty in eliminating infection in these host cells will represent a key part of future antiviral therapy of these diseases, including chlamydia and listeria.
Abstract: Phagocytic cells are critical for defense against infection, but also play a key role in inflammation. Phagocytic cells engage in obligatory events, including attachment to blood vessel walls, activated chemotaxis, phagocytosis, and microbial killing. Attachment to blood vessels and extracellular membrane proteins depends on the activity of receptor proteins in the integrin class. In addition, phagocytic cells can recognize platelet-activating receptor and PADGEM protein presented by endothelial cells. Chemotaxis has been most widely studied to understand the transduction process. Activated chemotaxis depends on the interaction between GTP-binding proteins (leading to activation of phospholipase C or D), alteration of cellular calcium, and protein kinase-mediated phosphorylation of substrates. Phagocytosis depends on immunoglobulin and complement. It has been recognized that the phagocytosis of some opportunistic pathogens such as mycobacteria and legionella depend primarily on the third component of complement. Microbial killing depends on formation of reactive oxygen intermediates and microbial proteins. In addition, the formation of nitric oxide by phagocytes has recently received attention because of its importance in the killing of some fungi, protozoa, and tumor target cells. Phagocytes may act as hosts for some intracellular pathogens such as chlamydia and listeria. In addition, cytomegalovirus infects neutrophils and human immunodeficiency virus infects monocytic phagocytes. Difficulty in eliminating infection in these host cells will represent a key part of future antiviral therapy of these diseases.

4 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, Antiretroviral therapy that reduces viral replication could limit the transmission of human immunodeficiency virus type 1 (HIV-1) in serodiscordant couples.
Abstract: Background Antiretroviral therapy that reduces viral replication could limit the transmission of human immunodeficiency virus type 1 (HIV-1) in serodiscordant couples. Methods In nine countries, we...

5,871 citations

Journal ArticleDOI
TL;DR: This work presents a meta-analyses of the immune system’s response to chronic obstructive pulmonary disease and shows clear patterns of decline in the immune systems of elderly patients with compromised immune systems.
Abstract: Lionel A. Mandell, Richard G. Wunderink, Antonio Anzueto, John G. Bartlett, G. Douglas Campbell, Nathan C. Dean, Scott F. Dowell, Thomas M. File, Jr. Daniel M. Musher, Michael S. Niederman, Antonio Torres, and Cynthia G. Whitney McMaster University Medical School, Hamilton, Ontario, Canada; Northwestern University Feinberg School of Medicine, Chicago, Illinois; University of Texas Health Science Center and South Texas Veterans Health Care System, San Antonio, and Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, Texas; Johns Hopkins University School of Medicine, Baltimore, Maryland; Division of Pulmonary, Critical Care, and Sleep Medicine, University of Mississippi School of Medicine, Jackson; Division of Pulmonary and Critical Care Medicine, LDS Hospital, and University of Utah, Salt Lake City, Utah; Centers for Disease Control and Prevention, Atlanta, Georgia; Northeastern Ohio Universities College of Medicine, Rootstown, and Summa Health System, Akron, Ohio; State University of New York at Stony Brook, Stony Brook, and Department of Medicine, Winthrop University Hospital, Mineola, New York; and Cap de Servei de Pneumologia i Allergia Respiratoria, Institut Clinic del Torax, Hospital Clinic de Barcelona, Facultat de Medicina, Universitat de Barcelona, Institut d’Investigacions Biomediques August Pi i Sunyer, CIBER CB06/06/0028, Barcelona, Spain.

5,558 citations

Book ChapterDOI
TL;DR: The chapter discusses the metabolism of transition metals, such as iron and copper, and the chelation therapy that is an approach to site-specific antioxidant protection.
Abstract: Publisher Summary This chapter discusses the role of free radicals and catalytic metal ions in human disease. The importance of transition metal ions in mediating oxidant damage naturally leads to the question as to what forms of such ions might be available to catalyze radical reactions in vivo . The chapter discusses the metabolism of transition metals, such as iron and copper. It also discusses the chelation therapy that is an approach to site-specific antioxidant protection. The detection and measurement of lipid peroxidation is the evidence most frequently cited to support the involvement of free radical reactions in toxicology and in human disease. A wide range of techniques is available to measure the rate of this process, but none is applicable to all circumstances. The two most popular are the measurement of diene conjugation and the thiobarbituric acid (TBA) test, but they are both subject to pitfalls, especially when applied to human samples. The chapter also discusses the essential principles of the peroxidation process. When discussing lipid peroxidation, it is essential to use clear terminology for the sequence of events involved; an imprecise use of terms such as initiation has caused considerable confusion in the literature. In a completely peroxide-free lipid system, first chain initiation of a peroxidation sequence in a membrane or polyunsaturated fatty acid refers to the attack of any species that has sufficient reactivity to abstract a hydrogen atom from a methylene group.

5,033 citations

Journal ArticleDOI
01 May 1981
TL;DR: This chapter discusses Detecting Influential Observations and Outliers, a method for assessing Collinearity, and its applications in medicine and science.
Abstract: 1. Introduction and Overview. 2. Detecting Influential Observations and Outliers. 3. Detecting and Assessing Collinearity. 4. Applications and Remedies. 5. Research Issues and Directions for Extensions. Bibliography. Author Index. Subject Index.

4,948 citations

Journal ArticleDOI
TL;DR: The new STD treatment guidelines for gonorrhea, chlamydia, bacterial vaginosis, trichomonas, vulvovaginal candidiasis, pelvic inflammatory disease, genital warts, herpes simplex virus infection, syphilis, and scabies are reviewed.
Abstract: The MMWR series of publications is published by the Office of Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services, Atlanta, GA 30333.

4,563 citations