Search PubMed⌕ Search

Biomedical subjects

G Oliphant

Publications and source records attributed to G Oliphant.

At least 37 records · Page 2Linked to original sources
PubMed1981

Steroid concentrations in rabbit oviducal fluid during oestrus and pseudopregnancy.

The concentrations of progesterone and oestradiol in the oviducal fluid during oestrus and pseudopregnancy were measured. Progesterone concentrations ranged from 0.55 +/- 0.17 ng/ml during oestrus to a maximum of 2.86 +/- 0.82 ng/ml on Day 12 of pseudopregnancy. Serum progesterone concentrations were similar to those found in oviduct fluid during oestrus, but by Day 12 serum levels had risen to 14.13 +/- 1.97 ng/ml. Daily oviducal fluid oestradiol values ranged from 48.3 +/- 6.4 pg/ml to 119.7 +/- 23.6 pg/ml and were similar to serum concentrations.

Animals↗
PubMed1977

Nature of the rabbit acrosome reaction-inducing activity of follicular fluid.

Follicular fluid samples from rabbits, cats, pigs, women and cows had acrosome reaction-inducing activity (ARIA) on rabbit spermatozoa as determined by differential staining after incubation with these fluids. Activity was retained after dialysis and at least 50% was found to be labile when heated to 56 degrees C for as little as 20 min. The induction of the acrosome reaction by bovine follicular fluid showed a dependence on the concentration of follicular fluid and spermatozoa and on calcium ions, and had a pH optimum of approximately 8. Enzyme treatments showed that proteases destroyed the ARIA and this activity was completely blocked by treatment of bovine follicular fluid with goat anti-bovine antiserum. Electron microscope observations indicated the similarity of the reactions observed to that occurring in vivo. It is concluded that the rabbit acrosome reaction inducing-activity of bovine follicular fluid is a serum component(s), probably a protein(s) of high molecular weight.

Acrosome↗
PubMed1977

Hormone-mediated oviductal influence on mouse embryo development.

This study presents evidence that estradiol, mediated through oviduct fluid, may adversely affect the development of early embryos. Two-cell mouse embryos were cultured in Whitten-Biggers medium with or without 0.2 to 20 microgram/ml of estradiol or progesterone or in mouse oviduct fluid from donors treated with estradiol or estradiol and progesterone. Embryos cultured in fluid from estrogen-dominated donors were significantly less able to develop to morula (65%) or blastocyst (14%) than were those cultured in either Whitten-Biggers medium (91% and 41%) or progesterone-dominated fluid (87% and 36%). Transfer of cultured morulae and blastocysts to uteri of pseudopregnant recipients resulted in 2/3, 4/6, and 0/7 recipients' becoming pregnant for control, progesterone-dominated, and estrogen-dominated, respectively. When estradiol or progesterone was added directly to the control medium, no inhibitory effects were observed at levels higher than those found physiologically in plasma. Protein concentration and osmolalities for representative samples of oviduct fluid were 5.2 mg/ml and 329 mOsM for estrogen-dominated fluid and 1.6 mg/ml and 339 mOsM for progesterone-dominated fluid.

Animals↗
PubMed1976

Removal of sperm-bound seminal plasma components as a prerequisite to induction of the rabbit acrosome reaction.

When rabbit sperm were pretreated with media of high ionic strength (380 mOsM), which had previously been shown to facilitate removal of sperm-bound seminal plasma components, and subsequently treated with follicular fluid the acrosome reaction was completed rapidly. Treatment of the sperm with follicular fluid alone yielded a greatly decreased rate of acrosome reaction completion, and treatment with the high-ionic strength medium alone caused no visible alteration to the sperm. These results suggest that removal of the sperm-bound seminal plasma components destabilizes the acrosome and prepares it to undergo the acrosome reaction. This destabilization is virtually completed after a 5-minute preincubation of the sperm in high-ionic strength media. Direct comparison of epididymal and ejaculated sperm indicated that epididymal sperm acrosomes were apparently in the same stabilized condition as ejaculated sperm. The effect of the pretreatment by high-ionic strength media could be partially mimicked by pretreatment of sperm with alpha- or beta-amylase or neuraminidase but not by beta-glucuronidase, lipase, pronase, or trypsin. Comparison of the ability of bovine follicular fluid, rabbit follicular fluid, and rabbit serum to induce the rabbit acrosome reaction showed that bovine follicular fluid was 3 to 4 times more effective than rabbit follicular fluid and that rabbit serum was totally ineffective in producing the acrosome reaction. The data support a physiologic role for follicular fluids in the process of fertilization and indicate that removal of sperm-bound seminal plasma components is a prerequisite to efficient induction of the acrosome reaction.

Acrosome↗
PubMed1975

The macromolecular composition of Xenopus laevis egg jelly coat.

The three morphologically and functionally distinct jelly coat layers of Xenopus laevis eggs, J1, J2, and J3, were separated by manual dissection, solubilized with dithiothreitol, and physicochemically analyzed. The chemical composition of the three jelly layers varied from 37 to 48% protein and 63 to 52% carbohydrate. The carbohydrate consisted of hexosamines, galactose, and fucose. Some of the carbohydrate in each of the jelly layers was covalently linked to protein through O-glycosidic bonds as beta elimination of the carbohydrate moiety in the presence of alkali was observed. In agreement with a previous finding, covalently attached sulfate was localized within the innermost jelly coat layer, J1. Cellulose acetate electrophoresis at pH 8.0 resolved a total of nine macromolecular components from the three jelly coat layers differentially staining for protein and carbohydrate: J1 yielded two anodically migrating components; the middle layer J2 yielded two cathodically migrating macromolecular components; the outermost layer J3 contained five species, three anodic and two cathodic. Sodium dodecyl sulfate agarose gel electrophoresis analysis yielded nine unique species, six of which stained coincidently for protein and carbohydrate. Immunoelectrophoresis and Ouchterlony double diffusion analyses using antiserum to total jelly components resolved nine different antigenic species with cross-reactivity between one or two macromolecules in layers J1 and J3. Analytical sedimentation velocity centrifugation revealed eight distinct species all of which exhibited hypersharp schlieren patterns and whose s20,w values were highly concentration dependent. On the basis of these analyses, Xenopus laevis egg jelly layers are composed of at least 8-9 distinct macromolecular species. The majority of these macromolecules are uniquely associated with different jelly coat layers.

Animals↗
PubMed1975

Partial purification and identification of a reversible decapacitation factor from rabbit seminal plasma.

Efforts have been directed toward partial purification and identification of a reversible decapacitation factor from rabbit seminal plasma. Five fractions were consistently obtained following fractionation of rabbit seminal plasma on a Sephadex G-200 column. Only the first two fractions had decapacitation factor (DF) activity. On SDS polyacrylamide gel electrophoresis, several carbohydrate-and protein-containing components were found in each fraction from the Sephadex column. Further, DF activity could be obtained in the precipitate resulting from cetyl pyridinium chloride (CPC) treatment of the active fractions from the Sephadex G-200 column. In the comparison of the components observed with SDS gel electrophoresis throughout these fractionation procedures, the reversible decapacitation activity appeared to be associated with a component containing protein and carbohydrate. From these studies, then, reversible decapacitation activity of rabbit seminal plasma appears to be associated with a glycoprotein of an approximate molecular weight of 115,000.

Agglutination Tests↗