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Biomedical subjects

M Emam

Publications and source records attributed to M Emam.

11 recordsLinked to original sources
PubMed2006

Screening for cervical carcinoma using visual inspection with acetic acid.

OBJECTIVE: To assess the performance of visual inspection with acetic acid (VIA) as a screening test for early detection of cervical carcinoma in the Dakahlia Governorate in Egypt. METHODS: Diluted acetic acid (5%) was applied to the cervix during routine gynecologic examination. Women with positive results were referred for colposcopy. Those with negative results were referred for colposcopy only when they had clinical indications. RESULTS: Among the 5,000 women who were screened using VIA, 409 were referred for colposcopy. Cervical intraepithelial neoplasia (CIN) was diagnosed in 151 (60%) of the 253 women with positive screening results and in 4 of the 156 women with negative screening results. There were 39 women with high-grade and 116 with low-grade CIN. The sensitivity and negative predictive value of the VIA screening test was 97%. Its positive predictive value was 60% for all grades of CIN and 90% for high-grade CIN. CONCLUSION: Visual inspection with acetic acid, although associated with a relatively high rate of false-positive results, is a valuable test for the screening of cervical carcinoma.

Acetic Acid↗
PubMed1996

Abnormal zinc and copper metabolism in hepatic steatosis.

Abnormal Zinc and Copper metabolism were studied in rats with tetracycline-induced fatty liver and compared with normal rats. The present work recorded decreased serum zinc concentration with increased copper concentration in the tetracycline-injected rats. The results also showed that the liver and heart zinc were significantly decreased; meanwhile it was observed that the concentration of zinc in the kidney tissue of fatty liver rats was significantly raised in comparison with those of normal rats. Histopathological studies of the kidney tissue showed degenerative changes in the tables with areas of focal necrosis. Renal tubular necrosis in such cases is largely caused by the toxic degradation products of tetracycline metabolism. The kidney lesion together with impaired gastrointestinal absorption contributed to the hypozincaemia observed in the present results. Although the present data showed a significant reduction in serum zinc and significant rise in plasma insulin in the fatty liver rats there was nonsignificant correlation between the two variables as compared with the normal rats. The positive correlation between serum zinc concentration and reduced high-density lipoprotein cholesterol (HDL-C) emphasizes the role of zinc deficiency in atherosclerotic disease in fatty liver.

Animals↗
PubMed1989

Effect of ultraviolet radiation on Ia expression by keratinocytes.

Many skin diseases, such as graft-versus-host disease (GVHD), are marked by lymphocyte infiltrates in the skin. Severity of these diseases is often correlated with the induced expression of class II antigens (human, HLA-DR,; murine, Ia) by the keratinocytes. This suggests that HLA-DR-expressing keratinocytes may be involved in the pathogenesis of these diseases. Since some of these diseases are effectively treated with ultraviolet radiation (UVR), this study was conducted to determine whether UVR alters the keratinocyte expression of class II antigens. To test this hypothesis, 2 models of experimentally induced keratinocyte Ia expression were employed. First, athymic nude mice with one ear protected by electrical tape were exposed to UVR (450 J/m2/day on 4 consecutive days). They were then given an i.v. injection of normal mouse serum (NMS) to induce keratinocyte Ia expression. Keratinocytes in the UVR-exposed skin of these animals were not induced to express Ia; however, Ia-expressing keratinocytes were observed in the epidermis of shielded skin sites. Likewise, it was determined that UVR was capable of downregulating keratinocyte expression of Ia when administered to nude mice 7 d after receiving an injection of NMS. Second, employing a clinically relevant model, we found that Ia expression by keratinocytes in mice undergoing experimentally induced GVHD was abrogated by UVR treatment. This appeared to be a direct effect of the UVR, since keratinocytes in shielded skin sites and mucosal cells in the intestinal epithelium of animals with GVHD were shown to express Ia. These data provide compelling evidence for our hypothesis that decreased HLA-DR expression by keratinocytes in diseased skin treated with UVR is a mechanism by which UVR exerts its therapeutic effect.

Animals↗
PubMed1986

An animal model of antibody binding in cutaneous lupus.

To study antibody binding in cutaneous lupus, we used human skin grafted onto nude mice. By immunofluorescence examination, mice injected with anti-Ro (SS-A) sera from subacute cutaneous or neonatal lupus erythematosus patients showed evidence of human IgG deposited in the skin, while mice injected with anti-native DNA or normal sera did not. We present evidence that there is specific binding of anti-Ro (SS-A) antibodies to Ro (SS-A) antigen in the skin, and we propose that these antibodies may be directly involved in cutaneous disease.

Adult↗
PubMed1984

Biology of Langerhans cells: analysis by experiments to deplete Langerhans cells from human skin.

In vivo studies have demonstrated that various treatments of skin, e.g., UV irradiation, topical corticosteroids, and tape-stripping, will temporarily deplete the epidermis of Langerhans cells (LC). Whether this loss represents simply a loss of cell surface markers unique to LC, or actual depletion of cells, is unknown. By design, normal human skin transplanted to the congenitally athymic (nude) mouse is a system devoid of circulating precursors for human LC. Because LC have been shown to be of bone marrow origin, any depletion of these cells in this system should be permanent. Treatments to deplete LC from human skin grafts on nude mice after grafting included: (a) large doses of UV radiation (400 mJ/cm2 every 48 h, X 3), (b) potent high-dose topical corticosteroids (2.5 mg betamethasone valerate/cm2 every day, X 5), (c) tape-stripping (X 20). Treatments before grafting included: (a) treating donor skin with 900 R of gamma irradiation, (b) complement fixing monoclonal antibody to Ia-like antigens of LC, followed by fresh complement, (c) monoclonal antibody conjugated to toxins. Quantitation of the number of LC was analyzed on control and treated epidermal sheets using immunodiagnostic reagents, anti-HLA-DR, and surface ectoenzymes , ATPase. Results show that both UV irradiation and topical corticosteroids reduce the number of LC by these analyses. However, within 3 weeks, recovery to pretreatment levels has occurred. X-irradiation and tape-stripping were without effect. Despite evidence that the monoclonal antibody, complement, and toxic systems were delivered to the LC within the epidermis, there is no evidence that these treatments resulted in a decrease in LC. It appears that LC are currently either long-lived or replaced locally from a proliferative pool and that certain cell membrane determinants of human LC are somewhat differentially sensitive to UV radiation and corticosteroids.

Adrenal Cortex Hormones↗
PubMed1983

Biology of Langerhans cells: selective migration of Langerhans cells into allogeneic and xenogeneic grafts on nude mice.

A major question challenging immunobiologists relates to those mechanisms that control the selective movement of cells involved in immune and inflammatory processes at various tissue sites such as the skin. Little is known about those influences that control the selective migration of macrophage-like Langerhans cells (LC) to normal epidermis, where it is uniformly distributed. Mechanistically, this includes the interaction of blood-borne LC precursors with the vascular endothelium of the skin and those factors that control the migration of the LC into the avascular epidermal component of the skin. By using (i) monoclonal antibodies specific for I-region associated Ia antigens found on LC from various inbred strains of animals and (ii) the congenitally athymic (nude) mouse as an immunologically compromised recipient of allografts and selected xenografts, we developed a model system to study the factors that restrict LC migration into the epidermis. Using this model, which excludes the need to lethally x-irradiate graft recipients, we established that: (i) the ingress of LC does not show major histocompatibility complex restriction [LC of the nude host are capable of migrating into the epidermis of allogeneic and certain xenogeneic (rat) skin grafts]; (ii) host LC are incapable of migrating into the epidermis of guinea pig or human skin grafts; (iii) the ingress of host LC into the epidermis of the graft is not accompanied by an overgrowth of the graft by host epidermis; and (iv) LC or LC precursors are capable of dividing in the skin or, alternatively, represent an extremely long-lived cell population. The specificity of this model system provides a powerful tool to help understand many aspects of LC biology. Grafting human skin to the nude mouse not only provides a biologic support system for the graft but also is, by design, a system that is devoid of contaminating circulating precursor cell types. Manipulation of the experimental conditions is quite easy and provides a highly specific means to investigate many parameters of LC function.

Animals↗
PubMed1983

Expression of Ia antigen on epidermal keratinocytes after the grafting of normal skin to nude mice.

During the course of experimentation designed to evaluate the migration of host Langerhans cells (LC) into normal skin grafted onto nude mice, we observed that the epidermal cells of these grafts were induced to express la determinants solely of graft origin. The data presented herein indicate that the expression of la by normal epidermal cells correlates with the infiltration of host LC into the graft. This la expression is restricted to the keratinocytes within the epidermis of the grafted skin, is first observed 7 to 9 days post-grafting, and persists within the grafted skin for greater than 12 wk. The induction of la expression by keratinocytes appears to be the result of the environment that is provided by the nude mouse host and is independent of both passenger lymphocytes within the skin graft and allogeneic differences between graft and host. We strongly believe that these studies provide the basis for the development of an experimental animal model system for investigating the potential role that la expression by epidermal cells may play in enhancing the immune response to antigens encountered in the skin.

Animals↗
PubMed1981

Cell-mediated hyperacute rejection. I. Acute, accelerated, and hyperacute reactions.

The morphology of first-set rejection of allogeneic murine skin grafts differs strikingly from that usually seen subsequent to sensitization. In the former, graft epithelium appears to be the primary target; in the latter, the endothelium of graft vessels. This difference suggests that different subsets of effector T cells may be involved. This paper reports an attempt to isolate, for further characterization, a T cell population associated with first-set rejection. The relationships between acute and hyperacute rejection of organ transplants and of murine skin grafts are discussed, as is the possible role of endothelium-specific antigens and receptors sites.

Animals↗