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G S Lewis

Publications and source records attributed to G S Lewis.

71 records · Page 4Linked to original sources
PubMed1982

High molecular weight glycoproteins released by expanding, pre-attachment sheep, pig and cow blastocysts in culture.

Blastocysts isolated from sheep (Day 14--16), pigs (Day 16) and cows (Day 19) during the pre-attachment elongation phase were cultured for up to 30 h in a modified MEM medium in the presence of radioactive amino acids (L-[14C]leucine or L-[35S]methionine) to label protein and D-[3H]glucosamine to label complex saccharides. All the blastocysts released considerable quantities of non-dialysable radioactive material into the medium at an approximately linear rate over the course of the incubation. Ion-exchange chromatography on DEAE cellulose at pH 8.2 revealed that the major glucosamine-labelled product in the medium was a non-sulphated glycoprotein which eluted early in the salt gradient. None of the blastocysts produced any detectable glycosaminoglycan-like materials such as hyaluronic acid. The glycoprotein was purified by ion-exchange and gel filtration chromatography and had a molecular weight of greater than 660 000. Up to 100 micrograms of this material could be isolated from incubations of 2 sheep conceptuses. It was relatively resistant to protease hydrolysis and consisted of approximately 50% carbohydrate and 50% protein. The main monosaccharide constituents, as revealed by gas-liquid chromatography, were galactose and N-acetylglucosamine plus some mannose and fucose. No sialic acid was present. The linkages between the carbohydrate chains and the peptide appeared to be resistant to alkaline borohydride cleavage and were probably, therefore, N-glycosidic.

Animals↗
PubMed1981

Effect of estradiol-17beta on PGF and total protein content in bovine uterine flushings and peripheral plasma concentration of 13, 14-dihydro-15-keto-PGF(2alpha).

Two experiments were conducted to examine the effect of estradiol-17beta (E(2)-17beta) on content of immunoreactive prostagladin F(2)alpha (PGF, ng) and total protein (TUP, mg) in uterine flushings, as well as concentrations of 13, 14-dihydro-15-keto-PGF(2)alpha (PGFM) in plasma (Pg/ml). In experiment 1, Holstein heifers were utilized in a single reversal trial in which either E(2)-17beta (3 mg in 2 ml saline/ethanol 50:50; n=5) or vehicle alone (n=6) were given intravenously on day 14 or 15 of the estrous cycle (Period 1) following an induced estrus (day of estrus = day 0). Treatment (Trt) groups were reversed in Period 2 (Day 14 or 15 of the second estrous cycle). Jugular venous plasma was obtained before treatment (Oh), and at 5, 6, and 9h posttreatment (PT). Uterine flushings were collected nonsurgically in vivo , per cervix, via Foley catheter at 6h PT (20 ml of .9% saline per uterine horn). E(2)-17beta did not significantly alter (E(2)-17beta vs vehicle; x(-) +/- S.E.M.) PGF (1674 +/- .11 +/- 338.39 vs 1889.91 +/- 400.24 ng; P> .10) or TUP (33.25 +/- 2.57 vs 39.16 +/- 3.04 mg; P > .10). However, E(2)-17beta increased (P < .05) plasma PGFM (E(2)-17beta vs vehicle) after treatment (0h, 113.2 vs 163.8; 5h, 312.5 vs 203.9; 6h, 324.5 vs 198.0; 9h, 323.2 vs 246.8, pg/ml). In experiment 2, crossbred beef cattle received comparable treatments of either E(2)-17beta (n=5) or vehicle (n=5) on day 14 or 15 postestrus. Jugular venous plasma was obtained at 0h PT, and at 6h PT. Uterine flushings (1.9% saline, 20 ml per uterine horn) and peripheral plasma were collected at slaughter. Estradiol-17beta increased PGF (30.07 +/- 5.94 vs 8.46 +/- 2.01 ng; P> <.05) in uterine flushings as well as PGFM in plasma (E(2)-17beta : 55.82 +/- 19.13 pg/ml, at 0h and 89.31 +/- 14.02 pg/ml, at 6h, vs saline: 103.46 +/- 50.73 pg/ml, at 0h and 17.78 +/- 14.22, at 6h). Estradiol-17beta stimulated uterine production and release of PGF and protein as measured in flushings (experiment 2) as well as plasma PGFM responses (experiments 1 and 2). Uterine and/or cervical stimulation of experiment 1 may have masked uterine response to E(2)-17beta.

Journal Article↗
PubMed1979

3-[(1,2,3-Thiadiazol-5-ylthio)methyl]cephalosporins.

The syntheses of ten 3-](1,2,3-thiadiazol-5-ylthio)methyl]cephalosporins, made by displacement of the 3'-acetoxy group by the novel thiol derivatives, potassium 1,2,3-thiadiazole-5-thiolate and dipotassium 1,2,3-thiadiazole-4-carboxylate-5-thiolate, are described. Several of the compounds showed good in vitro antibacterial activity against both Gram-positive and Gram-negative organisms. The subcutaneous in vivo activities against Staphylococcus aureus were generally less than that of cafazolin. Four of the compounds were administered orally and all were active; the 7 beta-(thiophen-2-acetamido) and 7 beta-(D-2-amino-2-phenylacetamido)-3-[(1,2,3-thiadiazol-5-ylthio)methyl] compounds were equally active by either route, with a PD50 of ca. 1 mg/kg.

Animals↗
PubMed1978

The effect of a progesterone-releasing intrauterine contraceptive device on uterine secretion of prostaglandin F2alpha and life-span of corpora lutea in the ewe.

Two studies were conducted to investigate the effect of a progesterone-releasing intrauterine contraceptive device (IUD) on uterine secretion of prostaglandin (PG) F2alpha associated with IUD-induced luteolysis in sheep. In bilaterally ovulating ewes receiving an IUD on day 3 (estrus = day 0) intrauterine release of progesterone (90 microgram per day) by the device did not prevent premature luteolysis or the increased concentration of PGF2alpha in uterine venous plasma on day 5 caused by conventional IUD's. In the second study a progesterone-releasing IUD (645 microgram per day) inserted adjacent to the intact ovary at unilateral ovariectomy on day 14 inhibited early luteolysis in the subsequent estrous cycle and reduced the uterine secretion of PGF2alpha on day 5, without affecting concentrations of progesterone in the peripheral circulation at the intervening estrus. It is suggested that locally delivered intrauterine progesterone can inhibit IUD-induced luteolysis in the ewe by suppressing the uterine secretion of PGF2alpha.

Animals↗
PubMed1978

Constituents of Cannabis sativa L. XIII: Stability of dosage form prepared by impregnating synthetic (--)-delta 9-trans-tetrahydrocannabinol on placebo Cannabis plant material.

Synthetic (--)-delta 9-trans-tetrahydrocannabinol impregnated on placebo Cannabis decomposed only 6.3% after being stored for 1 year at --18 degrees. Storage at 5 degrees and room temperature under various conditions led to severe decomposition. The amount of cannabinol observed when (--)-delta 9-trans-tetrahydrocannabinol decomposed indicates that cannabinol is not the only decomposition product.

Cannabis↗