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Biomedical subjects

S Mahmood

Publications and source records attributed to S Mahmood.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Immunosuppressive and virostatic actions of sterones from Petunia hybrida Vilm].

10 Ergostan-3-on derivatives presumably in the majority ergosta-1,4-dien-3-on derivatives could be isolated from Petunia hybrida VILM. Two were identified as the known compounds petuniasterone A and petuniasterone-C-22-O-acetate. The structures of two other compounds named petuniasterone-D-diacetate and 30-hydroxypetuniasterone A could be elucidated. The molecular formulas of the remaining substances were ascertained by mass spectroscopy. The petuniasterones inhibited the proliferation of stimulated human lymphocytes in non-cytotoxic concentrations, possessing therefore possibly immunosuppressive effects. Extracts of the plant and fractions containing a synergistically effective blue fluorescing substance retarded the multiplication speed of influenza viruses; pure petuniasterones were ineffectiv under our conditions in this regard.

Antiviral Agents↗
PubMed1987

Rapid diagnosis of cholera by coagglutination test using 4-h fecal enrichment cultures.

A simple, rapid, and reliable method to detect Vibrio cholerae in fecal specimens would assist in the management of cases of severe diarrhea, especially since most such cases occur in areas with minimal laboratory facilities. A coagglutination test was used to detect V. cholerae antigen in bile-peptone broth incubated with feces. In the technique, Staphylococcus aureus Cowan 1 coated with anti-V. cholerae O1 antiserum was tested with cultures incubated for 4 h. When 165 specimens were tested, the sensitivity, specificity, and accuracy of the test, compared with standard culture methods, were 97, 99, and 98%, respectively. These promising results were better than those of dark-field microscopy using the same specimens, and the test was logistically easy to perform. The coagglutination test using enrichment broth culture of feces is a simple and rapid method which may be used to confirm a diagnosis of cholera.

Agglutination Tests↗
PubMed1986

Changes in circulating levels of immunoreactive follicle stimulating hormone, luteinizing hormone, and testosterone during sexual development in the rhesus monkey, Macaca mulatta.

Basal serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) and the responsiveness of these hormones to a challenge dose of luteinizing hormone releasing hormone (LHRH), were determined in juvenile, pubertal, and adult rhesus monkeys. The monkey gonadotrophins were analyzed using RIA reagents supplied by the World Health Organization (WHO) Special Programme of Human Reproduction. The FSH levels which were near the assay sensitivity in immature monkeys (2.4 +/- 0.8 ng/ml) showed a discernible increase in pubertal animals (6.4 +/- 1.8 ng/ml). Compared to other two age groups, the serum FSH concentration was markedly higher (16.1 +/- 1.8 ng/ml) in adults. Serum LH levels were below the detectable limits of the assay in juvenile monkeys but rose to 16.2 +/- 3.1 ng/ml in pubertal animals. When compared to pubertal animals, a two-fold increase in LH levels paralleled changes in serum LH during the three developmental stages. Response of serum gonadotrophins and T levels to a challenge dose of LHRH (2.5 micrograms; i.v.) was variable in the different age groups. The present data suggest: an asynchronous rise of FSH and LH during the pubertal period and a temporal correlation between the testicular size and FSH concentrations; the challenge dose of LHRH, which induces a significant rise in serum LH and T levels, fails to elicit an FSH response in all the three age groups; and the pubertal as compared to adult monkeys release significantly larger quantities of LH in response to exogenous LHRH.

Animals↗
PubMed1984

Effect of dietary thiamin deficiency on intestinal functions in rats.

The effect of dietary thiamin deficiency has been studied on intestinal functions and chemical composition of brush border membranes in rats. Intestinal uptake of glucose, glycine, alanine, and leucine was significantly stimulated in thiamin deficiency compared to pair-fed control group. Studies with glucose and glycine revealed that stimulation of the absorption process occurs only in the presence of Na+ but not in its absence. Km measured in the presence of 140 mM Na+ for glucose and glycine uptakes was reduced by 56 and 41%, respectively, but Vmax remained unaltered in vitamin deficiency. There was no change in these parameters in Na+-free medium (Km = 31.3 and 23.3 mM; Vmax = 17.2 to 19.7 and 13.5 to 16.4 mumol/10 min/g wet tissue, respectively) under these conditions. The activities of brush border sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase were reduced by 42 to 66% in thiamin deficiency, compared to pair-fed controls. Kinetic studies with sucrase and alkaline phosphatase evinced that a decrease in Vmax (61 and 64%, respectively) with no change in Km (33.8 and 4.3 mM, respectively) was responsible for observed impairment in the enzyme activities in thiamin deficiency. Microvillus membrane proteins expressed on dry membrane basis were reduced by 20% in thiamin-deficient intestine. There was no difference in membrane sialic acid, cholesterol, phospholipids, and triglycerides fractions under these conditions. It is suggested that thinning of the microvillus membrane may be implicated in observed aberrations of intestinal functions in thiamin-deprived animals.

Alanine↗
PubMed1982

Karyotypic polymorphism in acute myelofibrosis.

Acute myelofibrosis (AMF) was diagnosed in a 59-yr-old black male in September 1978, on the basis of pancytopenia, lack of hepatosplenomegaly, fibrosis of the marrow, and paucity of teardrop red blood cells in the peripheral blood. Since then the patient has demonstrated an unusually long survival of 36 mo with a changing cytogenetic course. His initial 46, XY normal karyotype changed in 20 mo to trisomy 8, followed 1 yr later by 1:4 translocation in peripheral blood. Simultaneously with these changes, the fibrosis in the bone marrow progressively decreased, ultimately terminating in chronic granulocytic leukemia-like presentation with reversal to 46, XY karyotype. Fibroblast culture failed to show any evidence of cytogenetic abnormalities. The disappearance of fibrosis confirmed by trichrome and reticulin stains and lack of cytogenetic abnormalities in fibroblasts confirms the secondary role of fibrosis.

Acute Disease↗
PubMed1978

Mathematical prediction of drug distribution in vivo: studies with doxantrazole in rats.

A pharmacokinetic model incorporating 14 compartments and 29 transfer coefficients has been developed from experimental data obtained after intravenous administration of a single dose to describe the distribution of doxantrazole in the rate. The distribution calculated from the model agreed closely with that determined experimentally. In addition, the model was able to predict with considerable accuracy the distribution of doxantrazole after repeated dosing.

Animals↗
PubMedDate not supplied

Short communication: trophoblast proliferation is increased in chorionic villi from pregnancies with fetal trisomy 18.

Pregnancies with fetal trisomy 18 suffer from severe intrauterine growth restriction from the first trimester. This cross-sectional study of chorionic villi obtained from ongoing singleton pregnancies at 10-14 weeks of gestation, semiquantitatively examines chorionic villus stromal and trophoblastic cell proliferation rates in ongoing chromosomally normal and trisomy 18 pregnancies. Chorionic villi were stained using a standard immunohistochemistry protocol with a monoclonal antibody to the Ki-67 antigen and the number of Ki-67 positive trophoblastic and stromal cells per villous cross-section was compared between groups. The number of Ki-67 positive trophoblastic and stromal cells was significantly higher in the group (n=10) with trisomy 18 compared to the chromosomally normal group (n=25;t=2.1, P=0.03 and t=5.3, P<0.001 respectively). Abnormalities in control of cell turnover during development may be important in the pathogenesis of the clinical features of trisomic pregnancies.

Adult↗
PubMedDate not supplied

Febrile episodes in children with cancer in the United Arab Emirates.

The febrile episodes encountered in our pediatric oncology unit over a 2-year period were reviewed. A total of 138 febrile episodes were recorded in 59 patients (29 with leukemia and 30 with a solid tumor). There was no difference in the number of episodes between leukemia and solid tumor patients, nor between neutropenic and non-neutropenic patients. The degree of neutropenia was more severe in leukemia patients. A total of 18.8% of the episodes were accompanied by positive blood cultures. Gram-positive bacteria were more frequent than gram-negative bacteria, and there were four anaerobic isolates. Seventeen episodes were accompanied by clinical signs of central venous line (CVL) infection. A total of 70.2% of the episodes resolved with a first-line antibiotic combination of flucloxacillin, piperacillin, and netilmicin, 27.5% required modification of the antibiotic combination, and three patients (5%) died due to gram-negative septicemia. These findings indicate that the pattern of infectious complications in the United Arab Emirates is now similar to that observed in Europe and the United States.

Bacteremia↗