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Biomedical subjects

I Mahmoud

Publications and source records attributed to I Mahmoud.

5 recordsLinked to original sources
PubMed2004

Prevalence of hantavirus antibody in patients with chronic renal disease in Egypt.

In Egypt, the etiology of chronic renal failure (CRF) is not well defined. A hospital-based case-control study was initiated in February 1998, to determine whether hantavirus infection is involved in chronic renal disease (CRD) in Egypt. The study enrolled 350 study patients with a history of CRF and 695 matched controls with CRD due to renal calculus or renal cancer, but with normal renal functions. Sera from cases and controls were tested for anti-hantavirus IgG using ELISA with a cell-lysate antigen from Hantaan virus prototype strain 76-118. A demographic questionnaire was completed for each study participant. Five of the 350 cases (1.4%), and seven of the 695 controls (1.0%) were antibody-positive to hantavirus, with a titer > or =1:400. The difference in antibody prevalence between the study cases and the control cases was not statistically significant (P = 0.48). All antibody-positive study cases and controls had been exposed to rodents. Data indicated that in Egypt, hantavirus seroprevalence in CRD patients is low, and hantavirus infections do not appear to be a significant cause of CRF.

Adult↗
PubMed2001

Two new flavonol glycosides from leaves of Koelreuteria paniculata.

Two new flavonol glycosides were isolated from dried leaves of Koelreuteria paniculata Laxm. (Sapindaceae) and characterized as 6,8-dihydroxy-afzelin and afzelin 3"-O-gallate, based on chemical and spectral evidences, in addition to nine known polyphenolic metabolites, including eight isolated for the first time from this species.

Egypt↗
PubMed1994

Continuous darkness and continuous light induce structural changes in the rat thymus.

It is known that neuroendocrine responses to environmental stimuli, such as light, can influence immune responses through the pineal gland. It is also known that periods of constant darkness and constant light cause stimulation and inhibition of melatonin secretion from the pineal gland, successively. In this study, we provide experimental evidence that changes in the rhythm of the photoperiod have considerable effects on thymic structure of the rat. Male albino Wistar rats were divided into 3 groups. Group 1 rats were kept in a dark room, group 2 in a room under a bright artificial light and group 3 (control) animals were exposed to a 12:12 h light: dark cycle. All animals were killed after 4 wk. In group 1, thymus weight increased by 315%, the increase in volume affecting the medulla (cortex 190%, medulla 655%). The absolute number of epithelial cells and lymphocytes increased both in the cortex and medulla. Thymic cortical epithelial cells were hypertrophied and contained numerous large clear vesicles. Perivascular spaces were enlarged. In group 2 thymus weight decreased by 53%, the reduction in volume affecting mainly the cortex (cortex 61%, medulla 27%). The absolute numbers of cortical epithelial cells and lymphocytes were decreased, and pyknotic lymphocyte nuclei were frequent both in the cortex and medulla. It is concluded that constant darkness causes hypertrophy and increased cellularity of the thymus, while constant light causes involution of the thymus and death of lymphocytes. These changes possibly reflect the well known immunostimulatory effects of melatonin acting directly or indirectly, on the thymic lymphocytes and epithelial cells.

Animals↗
PubMed1986

Direct toxic effect of iodide in excess on iodine-deficient thyroid glands: epithelial necrosis and inflammation associated with lipofuscin accumulation.

Involution of thyroid hyperplasia (induced by a low iodine diet and a goitrogen, propylthiouracil, PTU) was obtained in mice by administering a high or a moderate dose of iodide (HID or MID, respectively). In HID involuting glands, vasoconstriction was observed after 12 hr whereas necrosis and inflammation were very abundant as early as after 6 hr and maximal after 48 hr. They were not prevented by papaverine by which vasoconstriction was inhibited, but were inhibited by the continuation of PTU by which iodide oxidation and organification were inhibited. Lipofuscin inclusions in thyroid and inflammatory cells were always associated with necrosis. On the contrary, when involution was induced by MID or by HID + triiodothyronine (T3), or by T3 alone, neither necrosis nor inflammation occurred and apoptosis was the only mode of cell deletion. No lipofuscin inclusion occurred. Our results demonstrate that iodide in excess, after being oxidized or organified, is directly toxic for iodine-deficient thyroid cells. The presence of lipofuscin suggests that its toxicity is mediated by lipid peroxidation, a consequence of production of free radicals in excess.

Animals↗