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W. R. DUKELOW

Summary.

Fifty-six squirrel monkeys were studied to develop means of accurate ovulation induction. Ovaries were exposed to determine ovulation time. Pre-treatment with progesterone to suppress spontaneous ovulation (5 mg daily for 5 days) was followed by : (a) no fsh, (b) 1 mg fsh, (c) human menopausal gonadotrophin (hmg), equivalent to 75 i.u. fsh, or (d) 200 i.u. pregnant mare's serum gonadotrophin (pmsg), each for 4 additional days. Ovulation was induced in 43% of the animals with either 250 or 500 i.u. of human chorionic gonadotrophin (hcg) administered intravenously (i.v.) or intramuscularly (i.m.). Four double ovulations were observed, the others were single ovulations. No follicular development occurred in animals which did not receive an exogenous source of fsh. fsh was superior to hmg and pmsg in its ability to promote follicular growth. Nearly twice as many animals ovulated after 500 i.u. hcg than with 250 i.u. Injection of the hcg i.v. or i.m. did not affect the percentage of animals that ovulated but greater variation in the time of ovulation was noted with i.v. injections.

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J. M. R. RAWSON and W. R. DUKELOW

Summary.

Laparoscopic observation of the ovaries of seventeen adult regularly cycling Macaca fascicularis was made during their menstrual cycles at the optimal time for detecting follicular development. Preovulatory morphology, follicular rupture and immediate postovulatory morphology were noted and photographed. Data are presented correlating the duration of the follicular phase and the luteal phase with that of the total cycle.

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R. M. HARRISON and W. R. DUKELOW

An in-vitro system for the fertilization of superovulated rabbit ova recovered from the ovarian surface and from the oviducts was used to study uterine-oviducal relationships in connection with sperm capacitation. Spermatozoa recovered from ligated uterine horns as early as 8 hr after mating were capacitated although they fertilized periovarian ova at a lower level than spermatozoa from control uteri.

In the last decade, a number of factors have been found which aid an in-vitro fertilization system. Replacement of serum by bovine serum albumin (BSA) (Brackett, 1966) and the maintenance of high humidity and prevention of evaporation from culture dishes (Brackett & Williams, 1965) have augmented the earlier work of Chang (1955, 1959) and Bedford & Chang (1962). Using the techniques first described by these workers and some new

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R. M. HARRISON and W. R. DUKELOW

Summary.

Ovulation induced in squirrel monkeys is completely blocked by daily injections of 500 μg of megestrol acetate. Levels of 50 to 250 μg either do not inhibit or only partially inhibit ovulation.

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D. A. JEWETT and W. R. DUKELOW

Summary.

The current investigation adapted photographic techniques to the laparoscope to characterize the morphology of follicular development in Macaca fascicularis. A vascular network was found to emerge on the surface of the ovary 30 hr before ovulation and provided the most reliable indication of follicular development. Within 10 hr of ovulation, a single vessel became established on the centre of the follicular wall. Stigmata were observed on either side of this vessel. Postovulatory follicular changes permitted the diagnosis of ovulation by laparoscopy.

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AUDREY E. LEE and W. R. DUKELOW

In oestrogen-primed mice, progesterone stimulates stromal mitosis and inhibits epithelial mitosis (Finn & Martin, 1967; Martin & Finn, 1968). In rabbits, however, endometrial proliferation is stimulated by progesterone. This report describes DNA synthesis (measured by [3H]thymidine incorporation) and mitosis in the uterine epithelium of ovariectomized rabbits treated with oestrogen and progesterone, and in intact animals during early pregnancy.

Mature New Zealand White rabbits were given 5·0 mg colchicine (1·0 mg/kg body weight) in 1·0 ml water intraperitoneally 6 hr before death. The `mitotic index' refers to the percentage of mitoses accumulated during this 6 hr period. One hour before death, the rabbits were anaesthetized with sodium pentobarbitone and 100μCi [3H]methylthymidine (s.a. 20 Ci/mmol, from

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H. N. CHERNOFF and W. R. DUKELOW

Summary.

Decapacitation factor (DF) was extracted from rabbit seminal plasma with a chloroform : methanol solution resulting in a considerable purification, based on dry weight.

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T. J. Kuehl and W. R. Dukelow

Summary. Synthetic TPAL, a polypeptide reported to occur naturally in hamster zygotes, was tested at doses of 3 or 18 μg/day for antiovulatory activity in cyclic hamsters (for 4 days) and squirrel monkeys (for 5 days) induced to ovulate. The TPAL treatment did not alter the ovulatory response in hamsters or monkeys.

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SEIICHIRO FUJIMOTO, NAHID PAHLAVAN and W. R. DUKELOW

Current literature indicates that chromosomal imbalance is causally related to some developmental anomalies and wastages in utero. While the incidence of gross chromosomal abnormalities in the human newborn population is estimated to be 0·5% (Lubs & Ruddle, 1970), much higher incidences have been reported in spontaneous and threatened abortions (Carr, 1965; Geneva Conference, 1966; Makino, Ikeuchi, Sasaki, Muramoto, Shimba, Fujimoto & Matsuda, 1967; Ikeuchi, Sasaki, Kohno, Hayata & Fujimoto, 1972).

On the other hand, it has been observed experimentally, on the basis of differences between the numbers of CL and conceptuses, that early embryonic wastage is a common phenomenon in some laboratory mammals (Falconer, 1960; Ohzu & Makino, 1964). Some workers (Ford & Woollam, 1963; Shaver & Carr, 1967; Kinsey, 1967; Hansen-Melander & Melander, 1971) have described techniques to stain blastocyst cells of rabbits for chromosomal analysis.

Recently, in rabbits, Hansen-Melander & Melander (1971) reported on three cases of chromosomally

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N. C. Cosby and W. R. Dukelow

Summary. Preimplantation embryos obtained from immature superovulated B6D2F1 female mice were microencapsulated in sodium alginate singly, in multiples of 2 or 3, or denuded of their zona pellucida. Encapsulated embryos developed in vitro at a rate similar to control embryos. Development of zona pellucida-free embryos was significantly less than that of intact embryos, but there was no difference between encapsulated and non-encapsulated zona pellucida-free embryos. Development of 2- and 4-cell embryos in sodium alginate was independent of cell stage. This report demonstrates the usefulness of a viable, biodegradable embedding material for the microencapsulation of manipulated preimplantation mammalian embryos.

Keywords: embryo; microencapsulation; sodium alginate; zona pellucida; mouse