Patrick P. L. Tam

Changes in metabolism and hepatic ultrastructure induced by estradiol and testosterone in immature female Epinephelus akaara (Teleostei, Serranidae).

SummaryEstradiol injections increase serum level of calcium, amino acid, glucose, protein, ammonia and creatinine in immature Epinephelus akaara, and also increase levels of total lipid, cholesterol, phospholipid and esterified fatty acids. Hepatic protein, glycogen and lipid concentrations also rise after estradiol treatment, and some hepatic enzymes participating in the metabolism of nitrogen, lipid and carbohydrate, show increased activity. Serum vitellogenin levels are increased. Testosterone treatment increases serum protein, total lipid, cholesterol, amino acid and ammonia levels, and also hepatic glycogen content, but in contrast to estradiol treatment, testosterone does not change serum vitellogenin, glucose, calcium, phospholipid, esterified fatty acid and creatinine levels, nor the hepatic lipid and protein content. A small number of hepatic enzymes shows an increased activity. Vitellogenic fish show biochemical changes similar to that of estradiol-treated fish, but are different from those of immature fish. Estradiol treatment induces ultrastructural changes in the hepatocytes of immature fish that are similar to those found in vitellogenic fish. These include a proliferation of rough endoplasmic reticulum and Golgi apparatus, and an increase in glycogen and lipid, all indicative of enhanced metabolic activity.

Effects of momorcharins on the mouse embryo at the early organogenesis stage

Previous studies showed that the two forms of momorcharins which are isolated from seeds of Momordica charantia L. are effective in inducing early and midterm abortions in the mouse. Momorcharins were found to be teratogenic to the cultured mouse embryos at the early organogenesis stage. Morphological abnormalities were seen in the head, trunk and limbs. Ultrastructural studies on the visceral yolk sac of the momorcharin-treated embryos showed that the endodermal layer was deranged, membrane invaginations at the apical surface were decreased and intercellular space became distended. It is likely that the teratogenic action of momorcharins on mouse embryos in vitro is mediated through the deleterious effects on the visceral yolk sac, which functions as a vital transport organ for the conceptus at the immediate post-implantation period.

Sexual maturation in the black seabream, Mylio macrocephalus Teleostei, Sparidae: changes in pituitary gonadotropes, hepatocytes and related biochemical constituents in liver and serum.

SummaryThe black seabream, Mylio macrocephalus, exhibits the phenomenon of sex segregation. Immature fish are developing hermaphrodites, and show a considerable overlap with mature males in their body weights. Mature females tend to be the heaviest group. Fish can be classified into immature, developing and mature groups, with a further division into definitive males or females in the two latter groups. The developing groups still have bisexual gonads, whereas mature males have testes with only a comparatively inconspicuous portion of ovarian tissue, and mature females possess ovaries with vitellogenic oocytes and a greatly regressed testicular component. In the present study, monthly samples were collected over a 3-year period, and changes in pituitary gonadotropes and liver tissue studied by light, and electron microscopy. Seasonal changes in serum constituents were also studied by biochemical techniques.Gonadotropes increased in number and became hypertrophied during sexual maturation, showing an enhanced cytoplasmic vacuolation and degranulation of alcian blue- and periodic acid-Schiff-positive material. The levels of various biochemical constituents in the liver and serum of developing fish tended to be intermediate between those recorded in the immature and mature groups. In mature fish, the serum levels of glucose, sodium and calcium were elevated, but hepatic glycogen content was less than the developing group, and hepatocytes contained activated mitochondria. The seasonal changes in pituitary cytology, hepatic ultrastructure and serum constituents, could be correlated with the metabolic adaptations to sexual maturation.

A correlative study on the embryotrophic property of patient’s serum and the outcome of in vitro fertilization of human oocytes

The embryotrophic property of patients serum previously used for in vitro fertilization (IVF) was studied by culturing postimplantation organogenesis-stage mouse embryos in a medium containing equal parts of Dulbeccos modified Eagles medium and the patients serum. Results of embryo culture experiments were generally found to correlate well with the outcome of IVF. Serum of patients whose oocytes were fertilized and developed to cleavage-stage embryos scored highest for embryotrophic parameters such as morphologic score and protein content of the mouse embryo. There was no significant difference in terms of serum embryotrophic activity between patients who became pregnant after embryo transfer and those who did not. When mouse embryos were cultured in serum from cycles with poor IVF results, i.e., oocytes failed to be fertilized or fertilized oocytes failed to cleave or cleave abnormally, significantly retarded embryonic growth and a higher incidence of malformed embryos were observed. However, in two cases where IVF failed as a result of poor semen quality, the patients serum was found to be supportive of mouse embryonic development.

Localization of fucosyl glycoconjugates in human oocytes following insemination for in vitro fertilization

Human oocytes that failed to cleave after insemination were examined for the presence of fucosyl glycoconjugates in the perivitelline space by staining withUlex europeaus lectin conjugated to fluorescein isothiocynate. Oocytes that formed two or three pronuclei following first insemination always exhibited positive lectin staining similar to that observed with in vitro fertilized mouse oocytes. Among those oocytes that failed to form any pronuclei after the first insemination attempt, only 5% contained lectin positive substances in the perivitelline space. Upon reinsemination, a higher percentage of those oocytes produced lectin-positive materials, although pronuclei were still absent. The appearance of fucosyl glycoconjugates in these oocytes might be the result of the release of cortical granules triggered by sperm penetration or, more likely, due to spontaneous granule discharge in senescent oocytes.

Changes of Acid and Alkaline Phosphatase Activities in the Developing Mouse Brain

Acid and alkaline phosphatase activities in the mouse cerebrum, brainstem and cerebellum increased during the late fetal and perinatal period and reached a maximum on postnatal day 28 (P28). Myelination was most extensive on P28-P45 in the brainstem and in the cerebellum, and phosphatidic acid phosphatase activity concomitantly decreased to a low level after birth. The changes in acid and alkaline phosphatase activities correlate more with the extent of myelination than with the overall brain tissue growth.

Beta-Endorphin levels in the preovulatory follicles and the outcome of in vitro fertilization

The level of immunoreactive beta-endorphin-like (IR-β-EP) material(s) was determined in follicular fluid samples obtained from patients treated for in vitro fertilization (IVF). Follicles containing morphologically mature oocytes had slightly lower concentrations of IR-β-EP. The total IR-β-EP content was similar in follicles with oocytes at different degrees of maturity. A smaller amount of IR-β-EP in the follicle fluid was associated with a greater developmental potential of the oocytes, which formed embryos that reached the three- to six-cell stage at 40–44 hr after insemination (r=−0.35, P<0.026). A higher IR-β-EP content was seen in fluid samples containing oocytes that remained uncleaved after fertilization (P<0.05 by Duncans multiple-range test).

Successful oocyte retrieval and in vitro fertilization following ultrasound-directed aspiration of endometriomas

A 25-year-old Chinese woman with a 5-year history of infertility was referred for IVE She had bilateral cystectomies in April 1984 for endornetriosis, followed by further medical treatment with Danazol, 200 mg tid, for 9 months. Both fallopian tubes were blocked and the endometriornas recurred. Two days before her IVF treatment, ultrasound examination showed two endometriomas measuring 5.5 x 3.5 and 4.8 x 4.0 cm on the left and right, respectively. Using a 16-gauge needle passed transvesically under ultrasound guidance with local anesthesia, 20 and 10 ml of chocolate material was aspirated. During the treatment cycle, superovulation was induced by giving 100 mg of clomiphene citrate on days 2-6 and 2 ampoules of human menopausal gonadotropin (hMG) on days 6-9. On day 11, the dominant follicle measured 2 crn and the plasma estradiol was 6127 pmol/liter. Ten thousand units of human chorionic gonadotropin (hCG) was given and outpatient transvesical ultrasound collection 36 hr later yielded five oocytes. Four embryos were transferred 30 hr later at the pronuclear stage. A biochemical pregnancy was recorded by a transient rise in hCG, 23 IU/liter, 7 days following the transfer.