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Biomedical subjects

B Raffel

Publications and source records attributed to B Raffel.

7 recordsLinked to original sources
PubMed1998

Differential expression of bcl-2 and susceptibility to programmed cell death in lymphocytes of HIV-1-infected individuals.

The bcl-2 protooncogene encodes an inner mitochondrial membrane protein that blocks programmed cell death. There is now increasing evidence that regulation of bcl-2 expression is a determinant of life or death in normal lymphocytes. In this study, we examined bcl-2 expression in lymphocytes from human immunodeficiency virus type 1 (HIV-1)-infected and healthy subjects by flow cytometry. bcl-2 expression was detected in more than 97% of peripheral blood lymphocytes in both healthy and HIV-infected individuals. It was consistently observed that CD4+ lymphocytes from HIV-1-infected individuals with less than 200 CD4+ cells/microliter expressed significantly less bcl-2 than healthy controls. In contrast, bcl-2 expression in CD8+ lymphocytes of these patients was significantly enhanced. No significant alteration of bcl-2 expression was found when lymphocytes of healthy individuals were polyclonally activated in the presence of various regulatory cytokines. Cells undergoing apoptosis showed significantly lower bcl-2 expression than viable cells. Staining of apoptotic cells revealed that lymphocytes from HIV-1-infected subjects were characterized by an increased susceptibility to programmed cell death which was not restricted to a particular lymphocyte subset. Despite significantly different bcl-2 expression in CD4+ and CD8+ lymphocytes of HIV-1-infected individuals with less than 200 CD4+ cells/microliter, no difference could be observed concerning their susceptibility to undergo apoptosis. Therefore, we conclude that sensitivity or resistance to in vitro induction of apoptosis does not directly correlate with bcl-2 expression.

Adult↗
PubMed1997

Ex vivo induction of apoptosis in lymphocytes is mediated by oxidative stress: role for lymphocyte loss in HIV infection.

Programmed cell death (apoptosis) of T-lymphocytes observed in human immunodeficiency virus (HIV) infected individuals could be linked to oxidative stress. Therefore, we have investigated whether reactive oxygen species (ROS) induce apoptosis, which might contribute to the cell loss during progression of HIV-1 infection. ROS were generated in peripheral blood mononuclear cells (PBMC) obtained from HIV-1-positive patients and from healthy controls by stimulation with bacteria or by treatment with hypoxanthine/xanthine oxidase, which has been shown to generate ROS without direct involvement of cytokines. A dose-dependent inhibition of ROS formation correlated with the reduction of apoptosis induced by both bacterial and hypoxanthine/xanthine oxidase stimulation, suggesting that ROS generation was responsible for the induction of apoptosis. In addition, hydrogen peroxide (H2O2) rather than superoxide (O2.-) was observed to induce apoptosis. ROS-dependent apoptosis was shown to be independent of cytokines such as tumor necrosis factor-alpha (TNF-alpha). ROS-induced apoptosis was significantly enhanced in HIV-infected subjects even in the very early stages after infection. Moreover, ROS-mediated apoptosis was not restricted to a particular lymphocyte subset. In view of the diminished oxidative resistance of HIV-infected individuals, our results suggest that ROS-mediated apoptosis might contribute to the deletion of lymphocytes and to the pathogenesis of the disease.

Acetylcysteine↗
PubMed1995

Decreased function of monocytes and granulocytes during HIV-1 infection correlates with CD4 cell counts.

Monocytes and neutrophils are involved in the primary immune response against opportunistic infections that occur during the progression of human immunodeficiency virus (HIV) infection towards development of acquired immune deficiency syndrome (AIDS). Phagocytic cells operate through the generation of reactive oxygen species which may be toxic for fungi, bacteria and viruses. In the present study we evaluated the function of monocytes and granulocytes in whole blood samples of 16 healthy controls, 12 HIV infected subjects who had not undergone significant infections and of 17 individuals with AIDS. Using flow cytometric methods we were able to determine phagocytosis and respiratory burst under conditions that reflect the normal environment of these cells. Compared with results in samples from controls, granulocytes and monocytes from asymptomatic HIV infected patients exhibited a significantly increased capacity to phagocytose bacteria. The production of reactive oxygen intermediates was in the normal range. In comparison to asymptomatic HIV infected individuals, patients with AIDS showed a significant reduction of phagocytosis and respiratory burst which correlated with the number of CD4+ cells. In comparison to controls, patients infected with HIV, whether they were symptomatic or not, revealed a significantly diminished number of oxygen radical producing cells compared with the number of phagocytic cells. These results indicate that monocytes and granulocytes show reduced antimicrobial activity even in early stages of HIV infection. This defect is only partly due to the HIV infection itself as neutrophils are not target cells for HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Technique for correction of areola misplacement with no new scars.

A method of changing the absolute position of the areola if poor positioning occurs after surgery is described. This method uses tissue expansion as an intermediate step and in so doing allows movement with no new scars. There is no reason that medial, lateral, or superior malpositions could not be corrected in this way. Most breast reduction patients with bottoming out will not need this two-stage procedure if the areola is not too high in the beginning.

Adult↗
PubMed1989

Segmental latissimus dorsi free flap: clinical applications.

For 15 years, the latissimus dorsi muscle has enjoyed a consistent reputation with reconstructive surgeons as a reliable pedicle or free flap transferred with or without a skin island. Previous laboratory investigation has delineated the neurovascular intramuscular anatomy. The segmental latissimus transfer makes use of the intramuscular anatomy such that a lateral segment of the muscle is denervated and transferred with the thoracodorsal vascular pedicle while the medial segment of the muscle remains in situ innervated normally and perfused by the dorsal perforating branches of the ninth, tenth, and eleventh intercostal vessels. In this article we report our results using segmental free flap transfer of the latissimus dorsi muscle in 11 patients. Electromyographic studies have been performed more than a year postoperatively to document the function of the residual latissimus left in situ. Our clinical observations show that the segmental free transfer of the latissimus dorsi muscle can be accomplished with little risk in those situations not requiring the entire muscle, and that the portion of the muscle not transferred continues to function well and improves the contour of the back.

Adolescent↗
PubMed1988

Primary lymphedema of the scrotum: surgical treatment and reconstruction.

Lymphedema of the penis and scrotum has significantly functional, cosmetic, psychological, and possibly malignant consequences for the affected patient. The authors have treated 3 patients with lymphedema of the scrotum by radical excision of all lymphedematous scrotal tissue and reconstruction using posterolaterally based scrotal flaps. Patients have been followed for six months to one year: There has been no recurrence of lymphedema. No complications were encountered, and cosmetic results were satisfactory.

Adult↗