Testosterone release in intact male dogs following the injection of a GnRH analogue.
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Animals↗
Biomedical subjects
E D Watson
Publications and source records attributed to E D Watson.
The effect of trypanosomosis on pregnancy in trypanotolerant Orma Boran cattle.
A study was undertaken to investigate the influence of trypanosomosis on the outcome of pregnancy in trypanotolerant Orma Boran (Bos indicus) exposed to natural tsetse challenge in an area of Kenya infested predominantly with Glossina pallidipes. Of 73 pregnant Orma heifers, 58 (79.5%) produced live calves at term, 13 (17.8%) aborted and 2 (2.7%) died of trypanosomosis. Of the 71 surviving animals, 22 (31%) were infected with Trypanosoma vivax , 21 (29.6%) T. congolense, and 26 (36.6%) had mixed infections with T. vivax and T. congolense. These results suggest that in areas of high trypanosomosis risk reproductive function is affected even in trypanotolerant cattle, and that both T. vivax and T. congolense can be responsible for the abortions observed in the field. It is suggested that maintenance of pregnancy in the face of trypanosome challenge was dependent on individual variation among the Orma cattle, but as challenge increased beyond the limits of effectiveness of trypanotolerance, disruption of pregnancy occurred.
Journal Article↗
The effect of experimental infection of Boran cattle in early and mid-pregnancy with Trypanosoma vivax.
Six susceptible Galana and five trypanotolerant Orma Boran (Bos indicus) cattle were infected experimentally with Trypanosoma vivax KETRI 2501 by cyclical transmission using Glossina morsitans during early and mid-pregnancy. Four pregnant animals, two of each Boran type were used as controls and remained uninfected throughout the study period. Three out of the six infected susceptible Galana Borans aborted, whilst one had a stillborn calf. None of the trypanotolerant Orma Boran cattle aborted and all carried their pregnancies to term. All control animals produced live calves at term. The mechanisms leading to disruption of reproductive function in susceptible Boran cattle were not clear but could involve a number of factors, including anaemia, weight loss and post-infection decline of plasma progesterone levels. It is concluded that infection with T. vivax disrupts maintenance of pregnancy in susceptible Galana Borans but does not affect maintenance of pregnancy in the Orma Boran, demonstrating their tolerance to infection with T. vivax.
Anemia↗
Suspected in utero infection in a boran heifer experimentally infected with Trypanosoma vivax.
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Animals↗
Lymphocyte subsets in the endometrium of genitally normal mares and mares susceptible to endometritis.
The density and distribution of MHC Class II positive cells and subpopulations of lymphocytes were studied in the endometrium of genitally normal mares and mares susceptible to endometritis. In genitally normal mares, more MHC Class II positive cells were present in the epithelium and stratum compactum during oestrus than dioestrus. Significantly more CD4+ and CD8+ lymphocytes were present in the stratum compactum than in the stratum spongiosum. CD4+ lymphocytes were present in greater numbers than CD8+ lymphocytes in the stratum compactum but approximately equal numbers were present in the stratum spongiosum and in lymphoid aggregates. Occasional CD4+ and CD8+ cells were seen in the luminal and glandular epithelium. Infrequently, B cells were present in the endometrium and were not observed in the epithelium. Numbers of T and B cells did not appear to be affected by cycle stage. In mares with endometritis, the densities of CD4+, CD8+ and B cells were significantly increased. Large aggregates of lymphoid cells which contained approximately twice as many CD4+ cells as CD8+ cells were present in the endometrium of these mares and all 3 subclasses of lymphocyte were seen occasionally in luminal and glandular epithelium.
Animals↗
Immunolocalization of aromatase P-450 in ovarian tissue from pregnant and nonpregnant mares and in ovarian tumours.
Aromatase P-450 (P-450arom) is a crucial regulatory enzyme that is necessary for conversion of androgens to oestrogens. Corpora lutea and follicles were obtained from the ovaries of cyclic mares and from mares at day 20 and days 40-70 of pregnancy. The presence of P-450arom within specific cell types was investigated by immunostaining to determine potential sites of oestrogen synthesis. Immunoreactivity for P-450arom was confined to the granulosa layer of non-atretic follicles > 5 mm in diameter and to corpora lutea at all stages of the oestrous cycle and during pregnancy. These findings confirm that aromatization of androgens occurs within the granulosa cells of the preovulatory follicle of the mare and that the corpus luteum of the mare has the capacity for oestrogen production if adequate androgen substrate is available. Granulosa cells in ovarian tissue from three mares with granulosa cell tumours showed little staining for P-450arom which suggests that these tumours have little aromatizing capacity.
Animals↗
Effect of undernutrition on progesterone concentration during the early luteal phase and mid-gestation in goats.
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Animals↗
Surgical removal of heartworms from a cat with caval syndrome.
Caval syndrome was diagnosed in a 4-year-old male domestic shorthair cat with severe dyspnea attributable to chylothorax. The diagnosis of heartworm infection was made on the basis of the ultrasonographic detection of a large number of adult heartworms in the right side of the heart and positive results for modified Knott's and heartworm antigen tests. Heartworms were surgically removed through an incision in the jugular vein, using a string-type horsehair brush and an alligator forceps. All clinical signs resolved after the surgery. Although treatment with agents that would kill the adult heartworms was considered, surgical treatment was used on the cat reported here. Surgical treatment may be the method of choice for use in cats with severe or persistent clinical signs attributable to infections with large numbers of heartworms.
Animals↗
Immunohistochemical study of immune cells in the bovine endometrium at different stages of the oestrous cycle.
Normal uteri were collected from 34 maiden heifers at slaughter and their stage of the oestrous cycle was determined from the ovarian structures. Cells expressing major histocompatibility complex (MHC) class II were widely distributed in the epithelium and lamina propria of the endometrium and were the most abundant population studied. The expression of MHC class II increased in the endometrium during the follicular phase of the cycle. Macrophages occurred throughout the stratum compactum and stratum spongiosum and their density did not appear to vary with the stage of the cycle. CD4+ cells were found mainly in the stratum spongiosum, whereas CD8+ cells were present mainly within the luminal and glandular epithelia and in the stratum compactum. The density of the populations of CD4+ and CD8+ cells increased markedly during the mid-to-late luteal and follicular phases, respectively, of the cycle. In the endometrium lymphoid aggregates were observed only rarely and no B cells were identified in any of the heifers.
Animals↗
Characteristics of cyclicity in maiden thoroughbred mares in the United Kingdom.
The characteristics of the cyclicity of 12 maiden thoroughbred mares kept in two groups were studied over a total of 58 cycles. On average, oestrus lasted 5.3 days and in 60 per cent of the cycles ovulation occurred in the last two days of oestrus. Oestrus and ovulation tended to be synchronised in each group of mares. The mean diameter of single-ovulating preovulatory follicles on the day before ovulation was 41.5 mm and during the seven days before ovulation they grew 2.5 mm/day. More than one follicle ovulated in 19 (33 per cent) of the cycles (seven double ovulations and 12 dioestrous ovulations). All the oestrous mares and 25 per cent of the mares with dioestrous ovulations had uterine oedema on the day before ovulation.
Animals↗
Measurement by ELISA of equine alpha-1-proteinase inhibitor in uterine flushings from mares.
An enzyme linked immunosorbent assay (ELISA) was developed and used to estimate the concentrations of the serine proteinase inhibitor, alpha-1 proteinase inhibitor (API), in uterine flushings recovered from mares at different stages of the oestrous cycle and before and after the induction of experimental endometritis. There was a significant increase in the concentrations of API and albumin relative to total protein in flushings recovered during oestrus compared with dioestrus but no difference was observed in the concentrations of these proteins relative to total protein before and after the induction of endometritis. A regression analysis revealed a significant correlation between the concentrations of albumin and API in the flushings examined, suggesting that the API was derived entirely from serum and was not produced locally in the uterus.
Animals↗
Testicular degeneration in 3 stallions.
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Animals↗
Isolation of cell populations from the mare corpus luteum: comparison of mechanical and collagenase dissociation.
Corpora lutea were obtained from mares at days 3, 10 and 14 after ovulation, and examined histologically. The morphology of isolated luteal cells obtained by either mechanical or collagenase dissociation of the tissue was examined and the cells stained to detect the steroidogenic enzyme delta 5, beta-hydroxysteroid dehydrogenase. The ratio of large:small cells was significantly higher for cells obtained from mechanically dissociated luteal tissue than for cells obtained by collagenase dissociation (P < 0.01). Cells obtained by both mechanical and collagenase dissociation secreted progesterone, although neither cell population responded to exogenous gonadotrophin with an increase in progesterone secretion. Homogenates of equine luteal tissue bound 125I-labelled human LH with high affinity and specificity, and the specific activity and binding affinity of luteal LH receptors did not change significantly from day 3, to days 10 and 14 after ovulation. However, mechanically dissociated cells on days 10 and 14 bound significantly more LH than did collagenase-dissociated cells on these days (P < 0.05). These results indicate that (i) collagenase dissociation of mare luteal tissue yields a population of cells that is unrepresentative of the corpus luteum, and (ii) the mare corpus luteum is not responsive to LH in vitro at the stages examined.
3-Hydroxysteroid Dehydrogenases↗
The effects of subnutrition on the components of the gravid uterus in the doe.
The effects of subnutrition on the caprine fetus and the other products of pregnancy were investigated in does. Two groups of does were fed on rations calculated to provide 100 and 25% of their energy and protein requirements for maintenance from 19 days before mating until 60 days after mating. Estrus was synchronized in does using PGF(2x). Approximately 60 days after natural mating, pregnant does were slaughtered, and the products of pregnancy were measured. Fetuses from the feed-restricted group were significantly lighter (P<0.05), had shorter crown-rump length (P<0.05), and the uterus contained a smaller volume of fetal fluids (P<0.02). Curved crown-rump length tended to be shorter and fetal placental membranes and cotyledons tended to be lighter (P<0.1) in the feed-restricted group. No significant difference was found between the 2 groups in the head length, number of placentomes, and weight of empty uterus. The number of fetuses affected the number of placentomes (P<0.001), weight of empty uterus (P<0.001), mass of total fetal fluids (P<0.001) and weight of ovaries (P<0.05), but not fetal measurements. Gestation length was found to significantly (P<0.001) affect all the fetal measurements but none of the placental measurements except for the total weight of cotyledons (p<0.001). The results of the study demonstrated detrimental effects of underfeeding on the caprine fetus and placenta.
Journal Article↗
The effect of high and low dose Theileria parva infection on the reproductive function of Boran/Friesian heifers.
Two separate experiments were carried out to find the effect of infection with low and high doses of Theileria parva sporozoites on the cyclical status of Boran/Friesian cross heifers. In each experiment, ten heifers were infected and another four heifers acted as controls. Routine monitoring of estrous behavior, determination of serum progesterone concentrations and palpation of the ovaries per rectum were used to assess the cyclical status of each animal. Two and eight animals died in the T . parva low (TpL) and high (TpH) dose experiments, respectively. Five of eight recovered animals in the TpL group cycled regularly postinfection, while three others had extended periods of ovarian dysfunction postinfection. Both infected and recovered animals in the TpH-group similarly had extended periods of ovarian dysfunction postinfection. All controls in both experiments cycled regularly throughout the study period. Differences in cyclical status were not related to the febrile response, parasitological or hematological differences. The animals that continued to cycle throughout lost the least amount of weight. Animals that stopped cycling lost between 16 and 29% of their initial body weights postinfection. In conclusion, this study confirmed previous anecdotal evidence that theileriosis has an adverse effect on reproduction. Results of this study suggested that this was as an indirect result of weight loss associated with infection and not directly attributed to pathology of target organs.
Journal Article↗
An immunohistological study of MHC class II expression and T lymphocytes in the endometrium of the mare.
The distribution of T lymphocytes and of cells bearing MHC Class II antigens in the endometrium of the mare was studied using an avidin-biotin-peroxidase staining method. The cells within the endometrium which expressed MHC Class II were macrophages, lymphocytes, monocytes, dendritic cells, epithelial cells and endothelial cells. MHC Class II expression increased significantly (P < 0.05) in the luminal epithelium and tended (P = 0.0573) to increase in the subepithelial layers during oestrus. Numbers of T lymphocytes did not differ between oestrus and dioestrus. MHC Class II expression and T lymphocyte numbers were not significantly different in samples collected on Day 14 of dioestrus and on Day 14 of pregnancy. The presence of endometritis greatly increased MHC Class II expression and T lymphocyte numbers within the endometrium.
Animals↗
Plasma concentrations of 13,14-dihydro-15-ketoprostaglandin F2 alpha in mares during uterine involution.
Twelve mares were allowed to foal naturally, after which they were monitored to study uterine involution. Starting on day 3 after parturition, the internal genital tract was examined per rectum manually and ultrasonographically every other day for changes in uterine characteristics and ovarian activity. By day 5, gravid and nongravid uterine horns were similar in size, and by day 7, uterine fluid was absent. On day 7 after parturition, endometrial biopsy samples were obtained for histologic evaluation, and uterine swab specimens were obtained for microbiologic culture. Uterine swab specimens from 10 of 12 mares had slight bacterial growth. The uteri of 8 of the 12 mares were histologically involuted by day 7. All mares ovulated 7 to 12 days after parturition. Concentrations of 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured in jugular plasma samples obtained daily for 21 days after parturition. Concentrations of PGFM were low by the day after parturition, and there was no significant correlation between uterine involution and PGFM concentrations in these mares. All 12 mares were bred at the first estrus after parturition, and 9 became pregnant.
Animals↗