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Biomedical subjects

S A Ali

Publications and source records attributed to S A Ali.

At least 109 records · Page 6Linked to original sources
PubMed1987

The skin of the male African catfish, Clarias gariepinus: a source of steroid glucuronides.

Steroid metabolism in the skin of mature male African catfish, Clarias gariepinus, reared in the laboratory, was studied in vitro by tissue incubations with [3H]pregnenolone, [3H]dehydroepiandrosterone, [3H]17 alpha-hydroxyprogesterone, [3H]androstenedione, [14C]11 beta-hydroxyandrostenedione, and [3H]testosterone as precursors. While pregnenolone was not converted to any other steroid, dehydroepiandrosterone was transformed mainly to 5-androstene-3 beta, 17 beta-diol. The products of 17 alpha-hydroxyprogesterone incubations were 5 beta-pregnane-3 alpha,17 alpha-diol-20-one, 5 beta-pregnane-3 alpha,17 alpha, 20 beta-triol, and 5 beta-pregnan-17 alpha-o1-3,20-dione. The major steroids of androstenedione incubations were etiocholanolone, testosterone, and androsterone. Testosterone was converted mainly to etiocholanolone and androstenedione, and only small quantities of 11 beta-hydroxytestosterone, 11-ketotestosterone, and 11-ketoandrostenedione were the metabolites found in 11 beta-hydroxyandrostenedione incubation. These results demonstrated the presence of the enzymes 5 alpha- and 5 beta-reductases and 3 alpha-, 11 beta-, 17 beta-, and 20 beta-hydroxysteroid dehydrogenases in the skin. From enzymehistochemical results it appeared that the steroid conversions take place in the epithelial cells. Moreover, the presence of UDP-glucose dehydrogenase, an enzyme involved in the synthesis of glucuronic acid, in these cells indicates the possibility of steroid glucuronide formation. Indeed significant amounts of water-soluble steroid conjugates, particularly 5 beta-dihydrotestosterone- and testosterone-glucuronide, were found in the incubations with androstenedione and testosterone, indicating the presence of the UDP-glucuronosyl transferase in the catfish skin. In the light of these results, a role of the skin of African catfish in the production of semiochemicals having pheromonal properties is discussed.

17-alpha-Hydroxyprogesterone↗
PubMed1987

Characterization of a transplantable adenocarcinoma of the mouse colon producing cachexia in recipient animals.

MAC16 is a chemically induced, transplantable adenocarcinoma of the colon passaged in inbred NMRI mice. At small tumor burdens (less than 1% of the host weight), weight loss was observed without a reduction in food intake. As the tumor mass increased, weight loss also increased and reached 33% of host body weight in females and 20% in males when compared with the weight of age-matched controls. The reduction in host body weight was directly proportional to the tumor size and was reversible when the tumor was excised. There was a preferential loss of body fat in tumor-bearing animals with an increase in the plasma level of free fatty acids, although there was a minimal elevation of ketone bodies. Tumor growth was accompanied by progressive hypoglycemia and a reduction in the plasma insulin levels. The decrease in plasma insulin may have contributed to the catabolic effects of progressive tumor growth.

Adenocarcinoma↗
PubMed1985

Blood levels of vanadium, caesium, and other elements in depressive patients.

Levels of vanadium and 29 other elements were measured in whole blood of 25 depressive patients, 13 recovered depressive, and 24 control subjects. Vanadium levels were normal in depressive patients, and did not change on recovery. Changes of doubtful significance were found in blood levels of copper, strontium and chromium on recovery from depressive illness. The depressive patients had reduced blood levels of caesium which increased towards normal on recovery. This finding is discussed in relation to pertinent neurochemical and behavioural effects of caesium.

Adult↗
PubMed1984

Modulation of human natural killer cytotoxicity by influenza virus and its subunit protein.

The influence of intact influenza virus and purified detergent solubilized haemagglutinin (HA) subunits from these viruses on human natural killer (NK) cell activity was examined. Effector cells incubated with whole influenza virus for 18 hr initiated the production of alpha interferon which was associated with the enhancement of NK cell activity. In contrast, purified influenza virus HA suppressed NK activity in a dose-dependent manner, when added at the onset of the cytotoxicity assay, or when used to pre-treated effector cells prior to assay for cytotoxicity against K562 target cells. Effector cells exposed to influenza HA for 90 min, washed and re-incubated in fresh medium for up to 18 hr, failed to regain their cytotoxicity. Suppression of NK cell cytotoxicity could not be ascribed to direct toxicity of HA preparations or residual detergent and preservative in these preparations. The augmented cytotoxicity of activated human effector cells was also susceptible to suppression by virus HA, and pretreatment of human PBL effector cells with HA for 90 min, prior to exposure to human alpha interferon caused NK effector cells to become refractive to the enhancing effects of HIFN. That direct interaction between influenza virus HA and effector cells was a requirement for suppression of activity was shown in experiments using Bromelain-released influenza HA, which would not be expected to bind to cells and which failed to suppress NK cell activity.

Bromelains↗
PubMed1983

Human spleen cells mediating natural killing: altered natural cytotoxicity of spleen effector cells from patients with carcinoma.

Spleen cells from eight patients with abdominal carcinoma and six patients undergoing major surgery for a variety of disease entities were assayed for natural cytotoxicity towards 51Cr-labelled K 562 target cells. Patients with abdominal cancer were shown to have relatively weak splenic natural cytotoxicity compared with the reactivity of effector cells from non-carcinoma patients. Nylon wool non-adherent spleen effector cells from cancer patients showed reduced cytolytic capacity compared with effector cells prepared from the spleens of other patients or peripheral blood mononuclear cells (PBMC) obtained from healthy individuals, whereas the splenic reactivity of non-cancer patients showed the same nylon wool separation profile as PBMC, high cytolytic activity being associated with nylon wool non-adherent effector cells. Splenic effector cell cytotoxicity from cancer and non-cancer patients was enhanced following exposure to human interferon, and inhibited by treatment with cholera toxin and simple sugars. Furthermore, fractionation of spleen cells on Percoll discontinuous density gradients demonstrated natural cytotoxic activity to reside predominantly in the low density cell fractions, similar to that found with NK cells from peripheral blood. Thus the properties described here for human cytotoxic spleen cells are similar to those described for peripheral blood NK cells, suggesting these two effector cell populations to be closely related, if not identical.

Adult↗
PubMed1979

Kinetics of red cell membrane phosphorylation: altered affinity of HS membrane protein acceptors.

Membrane ghosts were prepared from red blood cells of normal and hereditary spherocytosis (HS) subjects. Time dependent phosphorylation studies of the membrane (in the presence of gamma labelled AT32P) showed that the HS membrane appeared to incorporate less phosphate than the normal membrane but the results were not significantly different. Using the initial linear rate of phosphorylation and varying the ATP concentration, it was found that the Michaelis constant (Km) for the normal membrane was 24.8 microns ATP and Vmax was 0.120 nmol phosphate bound/mg membrane protein/min. These values for the HS membrane were found to be 39.0 and 0.118 respectively. In one family the affected mother and son each showed a positive cooperativity effect for similar reciprocal plots. This indicates that phosphorylation of various HS membrane proteins may be an ordered rather than random process and suggests biochemical heterogencity of the HS condition. The constants, Km and Vmax, however, were found to be similar to the rest of HS subjects studied. Crude extracts of the enzyme protein kinase, which catalyses the membrane phosphorylation, showed no significant difference in the Km and Vmax value in HS compared with that from normal red cells. The kinetic difference in phosphorylation is probably due to abnormalities in the membrane protein(s) which accept the phosphate from protein kinase in HS red cells.

Adenosine Triphosphate↗
PubMed1978

Isolation of Bacillus thuringiensis for microbiological control of insects.

Eleven of 180 local isolates, belonging to Bacillus thuringiensis, were tested for their pathogenicity to pinkbollworm larvae (Pectinophora gossypiella). Three strains, namely RS-25, RS-35, and RS-45, showed a positive insecticidal activity. Their activities based on the crystalline inclusion bodies. The LD50 (hours) for larvae was 8, 12, and 6 hours, respectively.

Animals↗
PubMed1978

An improved method for the extraction of cholesterol and phospholipids from the bovine spinal cord.

A pharmacopoeial grade of cholesterol and a separate phospholipid fraction can be obtained by this simple extraction procedure of bovine spinal cord. The tissue is collected in 5% (Wt/V) formalin. It is then separated from the formalin solution, minced and dried in a hot-air oven at 105 degrees C. Total lipids are extracted with petroleum ether. The cholesterol is separated from the phospholipids by extraction with a mixture of petroleum ether and acetone. The method allows for not only the recovery of the phospholipids but also a high yield of cholesterol without using saponification or tedious purification procedures.

Animals↗
PubMed1978

[Experimental studies on the therapeutic modification of intestinal adhesion formation].

One of the main problems encountered by the surgeon are visceral adhesions after abdominal surgery. This problem was studied in animal experiments by inducing peritoneal adhesions in 30 albino rats. The anti-inflammatory, resp. anti-adhesive effect of corticosteroids and antihistamines was tested by application of these drugs before, resp. after surgery. Anti-inflammatory proteolytic enzymes (Wobe-Mugos) were applied pre-, resp. postoperatively in two other groups. A fifth group served as controls. A modified cotton-pellet technique was used for the experiments. The best results were achieved when "Wobe-Mugos" was applied after surgery.

Animals↗
PubMed1977

Utilization of agricultural wastes of Aspergillus awamori for the production of glucoamylase.

The principal industrial use of glucoamylase is in the production of crystalline D-glucose. Aspergillus awamori was used. Variations in the specific type of carbohydrate source affected the yield of enzyme markedly. Of all the substrates tried, maltose supported satisfactory enzyme yields. Sucrose, lactose, fructose, and galactose gave abundant growth which seemed to be necessary but no sufficient condition for maximum yields. The specificity of the carbohydrate structure for gluco-amylase production was tried. The synthesis of enzyme was significantly stimulated when two-third of the starch in the medium was replaced by maltose. The adaptation seemed to be specific to maltose structure, since the substitution of maltose by structurally related compounds, a.o. lactose, in the medium did not give a comparable glucoamylase yield. Maltose or compounds composed of maltose gave maximum yields of enzyme. These results seemed to favour the theory that glucoamylase production is adaptive. Agricultural wastes produced locally in large quantities from plants manufacturing starch and other products were discussed. Rice bran, followed by glucose syrup, corn bran, wheat bran, and can sugar molasses supported good yields of glucoamylase.

Agriculture↗
PubMed1977

A simple and rapid method for the isolation of cholesterol from spinal cord of cattle.

A method is described for the large scale isolation of cholesterol from cattle spinal cord. Cholesterol is released from the lipo-protein by drying the wet tissues with calcium oxide. This treatment appears to prevent the extraction of polar lipids with acetone, which reduces the lipophylic properties of the solution and thus provides a method for almost exclusive extraction of cholesterol. The further role of calcium oxide is also discussed. The method evolved is simple, rapid and eliminates several previously required steps.

Animals↗