Search Results
You are looking at 1 - 10 of 59 items for
- Author: C Martin x
- Refine by access: All content x
Search for other papers by R. C. JONES in
Google Scholar
PubMed
Search for other papers by I. C. A. MARTIN in
Google Scholar
PubMed
Summary.
A transmission electron microscope was used to examine samples of ram semen after 30-fold dilution in a buffered glucose solution and storage at either 35° C or 5° C. The appearance of sections of heads and mid-pieces of spermatozoa was systematically scored so that the frequency of occurrence of several changes in ultrastructure in specimens could be compared between treatments.
Incubation of diluted semen at 35° C for 1 or 2 hr did not cause significant changes in acrosomes but a significant proportion of spermatozoa showed condensation of mitochondria or loss of material. Although the acrosomes of spermatozoa in undiluted semen were unaffected by incubation at 35° C for 2 hr, mitochondria had lost material and were scored as 'pale' in 80·5% of spermatozoa; only 13·5% of spermatozoa in the control samples were scored in this category.
Acrosomes and mid-pieces were affected by cooling to 5° C and storage at this temperature for up to 72 hr. The acrosome changes involved swelling and vacuolation or, in a small proportion of spermatozoa, swelling and vesiculation of the outer acrosomal membrane. Mid-pieces showed condensation of mitochondria and loss of material. The inclusion of 3% (v/v) egg yolk in the diluent reduced the frequency of these changes.
Search for other papers by R. C. JONES in
Google Scholar
PubMed
Search for other papers by I. C. A. MARTIN in
Google Scholar
PubMed
Summary.
In a factorial experiment skim milk, egg-yolk-citrate and synthetic diluents composed of fructose or lactose, sodium chloride and phosphate buffer containing 3·0% w/v of a lyophilized preparation of non-dialysable solids from (cow) milk were used as diluents for deepfreezing ram spermatozoa and for incubating spermatozoa at 37° C after thawing. All samples of semen were diluted forty-fold before freezing. Egg-yolk-citrate was inferior to skim milk as a diluent for freezing spermatozoa and for incubating spermatozoa after thawing. Of the two synthetic diluents, lactose synthetic was better for freezing spermatozoa whilst fructose synthetic was better for incubating spermatozoa after thawing. Only spermatozoa frozen in the lactose synthetic diluent and resuspended after thawing in the fructose synthetic survived incubation at 37° C for 2 hr as well as spermatozoa frozen and incubated in skim milk diluents.
Two factorial experiments compared egg-yolk-citrate and skim milk as diluents for freezing semen diluted from ten- to forty-fold. At ten-fold dilution, revival was much the same after freezing in milk or egg-yolk-citrate. A twenty- or forty-fold dilution was better than a tenfold dilution in milk, but revival was depressed at these higher dilution rates after freezing in egg-yolk-citrate. When semen was frozen at a tenfold dilution it was advantageous to resuspend spermatozoa in a diluent free of glycerol after thawing. A diluent based on Krebs—Henseleit— Ringer solution containing 0·5% w/v of non-dialysable milk solids was better for incubating spermatozoa after thawing than egg-yolk-citrate or milk.
A period of 5 hr equilibration at 5° C before freezing was better than 30 min equilibration.
Search for other papers by I. C. A. MARTIN in
Google Scholar
PubMed
Search for other papers by C. S. WALLACE in
Google Scholar
PubMed
Summary.
With the addition of a phase sensitive detector and a discriminator circuit to the impedance bridge (Rothschild, 1948), counts of the impedance change frequency (icf) of a semen sample can be recorded on a mechanical counter. Further separate circuits to indicate balance of the bridge have been added so that the cathode ray tube of the original instrument is no longer needed for balancing or counting icf.
Highest icf counts were recorded when the concentration of ram spermatozoa lay between 9 and 12 × 108 spermatozoa/ml. Activity fell rapidly in more concentrated samples tested at 38° C unless the sample was simultaneously dialysed against an isosmotic buffered saline diluent containing fructose.
There were no significant differences between the performance of four electrodes tested, but icf was depressed by the presence of an electrode in the sample for 10 min at 38° C before a reading was taken.
Search for other papers by I. C. A. MARTIN in
Google Scholar
PubMed
Search for other papers by C. W. EMMENS in
Google Scholar
PubMed
Summary.
Four treatment methods for the preparation of deep-frozen bull semen were tested for fertility in a factorial design involving the artificial insemination of 1728 first-service cows with the following results :
of non-returns to service at 3 months, with equal treatment groups of 432 cows. The improvement in fertility after equilibration in the presence of fructose was highly significant (P < 0·01), but not in its absence, when fertility was depressed even in equilibrated semen.
There was a higher revival rate of spermatozoa after the longer period of equilibration and the use of fructose in the diluent significantly improved the percentage of motile spermatozoa after thawing.
Search for other papers by L. Martin in
Google Scholar
PubMed
Search for other papers by C. A. Finn in
Google Scholar
PubMed
Summary. Chronically implanted IUDs consisting of silk suture threads induced decidualization in regions of the uterus remote from the suture site in ovariectomized mice treated with a regimen of progesterone and oestrogen which sensitizes the uterus to a decidual stimulus. In these conditions the IUDs did not inhibit decidualization induced by instilled oil, although they did so in pregnant animals of the same strain. Varying the dose of progesterone and oestrogen did not produce conditions in which IUDs inhibited oil-induced decidualization in ovariectomized mice and progesterone treatment did not prevent IUDs inhibiting decidualization in pregnant animals. However, when ovariectomized mice, sensitized as before, were primed repeatedly with oestrogen to simulate continuing oestrous cycles after IUD insertion, the IUDs inhibited oil-induced decidualization. This involved the premature loss of instilled oil from the uterine lumen and was associated with heavy infiltration of leucocytes into the luminal epithelium. Numbers of leucocytes free in the uterine lumen did not appear to be critical. It appears that contact between the oil and the luminal epithelial surface must be sustained for some length of time to induce a decidual reaction; brief contact is not sufficient to trigger the response.
Search for other papers by C. A. FINN in
Google Scholar
PubMed
Search for other papers by L. MARTIN in
Google Scholar
PubMed
Summary.
A single injection of 15 μg actinomycin D on Day 5 after mating interrupted pregnancy in five/five mice. To obtain information about the mode of action of the drug, its effect on the progress of the artificial decidual cell reaction was studied.
Ovariectomized mice were prepared for decidualization with exogenous hormones and decidualization induced by the intrauterine injection of arachis oil. Intraperitoneal injection of actinomycin D 7½ or 1½ hr before the decidual stimulus did not prevent the early stages of the decidual reaction but delayed by 24 to 30 hr the onset of decidual transformation of the stromal cells. It appears that the drug blocks the chain of reactions leading to decidual morphogenesis after the initiation of the reaction but that once the effect of the drug wears off, development of the decidua resumes provided the hormone conditions are adequate.
Search for other papers by C. A. FINN in
Google Scholar
PubMed
Search for other papers by L. MARTIN in
Google Scholar
PubMed
In a recent paper, it was postulated that the secretion of progesterone from the ovary during early pregnancy in the mouse does not start until the 3rd day after the finding of the copulation plug (Finn & Martin, 1969). This was based on the observation that, if pregnant mice were ovariectomized a few hours after mating and given progesterone before Day 3, the mitosis which normally occurs in the uterine glands and to a lesser extent in the luminal epithelium on Day 3 (Finn & Martin, 1967) is suppressed.
The object of the present work was to see whether exogenous progesterone given to entire pregnant mice before Day 3 would cause a similar change in the pattern of uterine mitosis on Day 3
Search for other papers by C. S. T. Pow in
Google Scholar
PubMed
Search for other papers by L. Martin in
Google Scholar
PubMed
The ovarian–uterine vasculature was examined in three Australian species of flying fox (Pteropus scapulatus, P. poliocephalus and P. alecto). Vascular casts and histological sections were used to determine the relationship between the blood supply and the localized endometrial reaction, which occurs ipsilateral to the ovulating ovary. The ovarian artery coils extensively just cranial to the ovary, gives off a branch to the ovary and continues caudally as the major vessel supplying the cranial tip of the uterus, where it anastomoses with the smaller uterine artery. The coil of the ovarian artery is completely enclosed by a venous sinus that drains the cranial pole of the ovary. The ovary is heavily encapsulated, with primordial follicles restricted to the caudal pole; thus, the corpus luteum is completely internal and placed cranially, close to the coil of the ovarian artery. This arrangement would allow countercurrent or crosscurrent transfer of ovarian steroids from ovarian vein to ovarian artery and on to the cranial tip of the ipsilateral uterine horn. The steroids could thus reach high concentrations locally and generate localized endometrial growth. Cranial to the coil, the ovarian artery is enclosed in a venous sinus that derives from uterine as well as ovarian veins. This would allow countercurrent transfer of bioactive substances from uterus to ovary.
Search for other papers by C. W. EMMENS in
Google Scholar
PubMed
Search for other papers by L. MARTIN in
Google Scholar
PubMed
Summary.
U-11100A is oestrogenic in vaginal smear tests in rats and mice with a subcutaneous med of ca. 500 μg and 50 to 100 μg respectively. It is also oestrogenic orally and intravaginally and in the tetrazolium reduction test. In all tests, however, the dose-response line turns down again with higher dosage, and full responses were not obtained at the highest dose levels tested. The compound is weakly anti-oestrogenic in both vaginal smear and tetrazolium tests in mice, but exhibits complex interactions with oestradiol, the oestrogen used.
U-11100A has an antifertility action when injected on Days 1 to 3 or 4 to 6 of pregnancy in the mouse, 50 μg/day being effective on either schedule. It is felt that this is an expression of its oestrogenicity.
Search for other papers by C. A. FINN in
Google Scholar
PubMed
Search for other papers by L. MARTIN in
Google Scholar
PubMed
