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Biomedical subjects

M C Chang

Publications and source records attributed to M C Chang.

At least 253 records · Page 14Linked to original sources
PubMed1978

Effect of antisera against eggs and zonae pellucidae on fertilization and development of mouse eggs in vivo and in culture.

A single intraperitoneal injection of female mice with rabbit antisera against denuded mouse eggs and isolated zonae pellucidae inhibited fertilization for at least 25--30 days. Intraperitoneal injection appeared to be more effective and lasted longer than subcutaneous or intramuscular injection but oral administration had no effect. Such a passive immunization of females given after fertilization had no effect on embryonic development or the sex ratio of fetuses. The fertilizing capacity of mouse spermatozoa was suppressed by treatment of the sperm suspension with anti-egg but not with anti-zona serum. Treatment of mouse eggs with these antisera did not affect their development to blastocysts in culture but did inhibit the shedding of the zona pellucida and attachment to the dish.

Animals↗
PubMed1978

Relationship between sperm concentration and polyspermy in intact and zona-free mouse eggs inseminated in vitro.

Intact and zona-free mouse eggs were cultured with preincubated (capacitated) spermatozoa for 1 or 4 hr. High proportions of eggs (84%--100%), examined either 1 or 4 hr after insemination, were undergoing fertilization in the intact and zona-free eggs in sperm concentration from 25--800 X 10(3) sperm/ml. The average number of spermatozoa attached to the zona pellucida and to the vitellus was only slightly increased as the sperm concentration increased. Polyspermy was increased from 25--200 X 10(3) sperm/ml but there was no clear correlation between the incidence of polyspermy and further increase of sperm concentration in both the intact and zona-free eggs. Besides a functional zona reaction, there was a definite vitelline block to further sperm entry. It seems that due to the chance collision of sperm and egg with the subsequent formation of a block mechanism in the zona pellucida and in the vitelline membrane within a short time, polyspermy cannot be increased by further increase of sperm concentrations.

Animals↗
PubMed1978

Endocrinological and physiological features after steroid treatment of male rats.

The effects of medroxyprogesterone acetate (Provera), testosterone propionate (TP), ethinyl estradiol (EE), and ethynodiol diacetate (ED) treatments on sperm population in different segments of the male rat reproductive tract, reproductive organ weights, circulating androgens and fertility were studied. Ten microgram TP given for five days reduced the sperm population and organ weights. A marked reduction in the number of sperm and reproductive organ weights was observed in males orally treated with estrogens. Only long-term (20 days) treatment with Provera (1 mg/day) significantly reduced sperm population and reproductive organ weights. Combination of TP and Provera resulted in a more pronounced reduction in sperm counts and organ weights. Among steroids studied, estrogen was the only compound which suppressed fertility and circulating steroid levels.

Androgens↗
PubMed1978

Fertilizable life of mouse eggs stored at 1 C and 25 C.

Unfertilized mouse eggs were suspended in various media for 1, 2, 4, 6 and 8 hours at 1 C and 25 C before exposure to spermatozoa in vitro. The largest number of eggs undergoing fertilization at both temperatures occurred after storage for 1 and 2 hours with the number decreasing over the remaining 6 hours. More eggs stored at 25 C appeared to be undergoing normal fertilization, especially after storage for 4 hours, when compared with eggs stored at 1 C. Various abnormalities associated with fertilization were visible in some eggs after storage at each time period and at both temperatures.

Animals↗
PubMed1977

In vitro fertilization of hamster eggs by ejaculated or epididymal spermatozoa in the presence of male accessory secretions.

In vitro fertilization of hamster eggs by ejaculated or epididymal spermatozoa in the presence of seminal plasma or male accessory gland secretions was examined. There was no difference in the penetration rates, the time of sperm penetration and the optimal sperm concentration between ejaculated and epididymal spermatozoa. The swelling of the zona pellucida, a high incidence of polyspermy, distortion of the vitellus and the degeneration of eggs were observed after incubation of ejaculated or epididymal spermatozoa in the presence of seminal plasma or accessory gland secretions. Using ejaculated spermatozoa, the fertilization rates of eggs with or without follicular cells were similar but fertilization by epididymal spermatozoa was inhibited by secretion of the seminal vesicle or ventral prostrate gland but not by that of the coagulating gland or the dorsal prostrate.

Animals↗
PubMed1977

Determination of seven unconjugated steroids in the blood and seminal plasma of the fertile male rabbit.

Seven unconjugated steroids were measured in the blood and seminal plasmas of fertile male rabbits by radioimmunoassay. The blood plasma testosterone concentration was 4--5 times that of the seminal plasma. Dehydroepiandrosterone, estrone and 17beta-estradiol were found in measurable amounts in the blood plasma; however, these steroid levels were slightly lower in seminal plasma. Androstenedione and 5alpha-dihydrotestosterone were present in equal quantities in both the seminal and blood plasmas. By contrast, seminal plasma pregnenolone level was about twice that of the blood plasma. The determination of seminal plasma steroids may lend itself as a complementary assessment to blood steroid determinations for the evaluation of the normal function of various reproductive organs.

Androstenedione↗
PubMed1976

In vitro fertilization of mouse and hamster eggs after freezing and thawing.

Mouse eggs (12-14%) and hamster eggs (87-94%) appear normal upon thawing after having been stored for 30 min to 25 h at -70 degrees C and -196 degrees C. While 89-98% of the normal appearing hamster eggs are capable of fertilization in vitro, only 4-13% of the mouse eggs can be fertilized. The ability of fertilized eggs to develop in culture and their viability upon transfer to pseudopregnant recipients is under investigation.

Animals↗
PubMed1976

Effects of wheat germ agglutinin on fertilization of mouse ova in vivo and in vitro.

Mouse ova with or without follicular cells (denuded) were treated with wheat germ agglutinin (WGA) in concentrations ranging from 5-500 mug/ml and fertilized in vitro. Ova subjected to concentrations greater than 10 mug/ml WGA were incapable of fertilization in vitro, although sperm were observed adhering to the zona pellucida after treatment in concentrations as high as 500 mug/ml WGA. At concentrations of 50 mug/ml or higher, WGA adversely affected the shape of the vitellus. Of various saccharides employed to block the effects of WGA D-glucose was the most effective. Injections of 0.03 ml of 100 mug/ml WGA into the ovarian bursa two to three hours before the expected time of ovulation had little or no effect on fertilization in vivo.

Animals↗
PubMed1976

In vivo and in vitro fertilization of hamster, rat and mouse eggs after treatment with anti-hamster ovary antiserum.

Rabbit antiserum against hamster ovary was examined on agargel diffusion plates against several hamster tissues, and also against rat and mouse ovarian extracts. Unabsorbed anti-hamster ovary antiserum showed eight to nine precipitin bands for hamster ovary and four to eight bands for other tissue extracts, but no bands against sperm antigens. Anti-hamster ovary antiserum also showed three to four bands for rat and one to two bands for mouse ovarian extracts. The present experiments confirmed previous reports for the hamster and mouse that treatment of eggs with anti-ovary antiserum blocked in vitro fertilization and that the extent of the inhibition was related to the formation of a precipitate on the zone pellucida. A single injection of anti-hamster ovary antiserum inhibited fertilization in mice but not in rats. In vitro fertilization of mouse eggs was also inhibited in the presence of such antiserum.

Animals↗
PubMed1976

Effects of various low temperatures, cryoprotective agents and cooling rates on the survival, fertilizability and development of frozen-thawed mouse eggs.

Frozen mouse eggs were examined to determine the effects of low temperatures, concentration of cryoprotective agents and cooling rates on their survival, fertilizability in vitro and subsequent development. Dimethyl sulfoxide administered at 1.5 M concentration was found to be the most effective cryoprotective agent. Upon thawing, 51% and 56% of the eggs appeared to be normal after having been cooled at 0.33 degrees C/min to -30 degrees C and -50 degrees C, but only 18% of the eggs appeared to be normal after having been cooled at the same rate to -75 degrees C. When eggs were cooled at 0.33 degrees C/min to -45 degrees C and the cooling rate increased to 1 degree C/min from -45 degrees C to -75 degrees C, 44% and 72% appeared normal upon thawing. Of the normal eggs fertilized in vitro from C3H mice, 65% cleaved to the 2-cell stage and 24% of the 2-cell eggs developed into blastocysts. Following the transfer of 17 blastocysts into three recipient mice, one mouse delivered three normal young.

Animals↗
PubMed1976

The inhibition of the conversion of testosterone into 5alpha-dihydrotestosterone in the reproductive organs of the male rat.

The inhibition of testosterone 5alpha-reductase activity by 3-oxo-4-androstene-17beta-carboxylic acid in the male reproductive organs of the rat was demonstrated in vitro. The medium for incubation of caput epididymis showed the highest concentration of 5alpha-dihydrotestosterone (5alpha-DHT) whereas the highest concentration of testosterone (T) was recorded in medium for incubation of decapsulated testis after two hours of incubation. The 3-oxo-4-androstene-17beta-carboxylic acid (1.58 X 10(-5)M) inhibited the conversion of T to 5alpha-DHT in all the organs tested (testis, caput and cauda epididymis and ventral prostate) under identical incubation conditions.

5-alpha Reductase Inhibitors↗