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Biomedical subjects

R M Kenney

Publications and source records attributed to R M Kenney.

At least 91 records · Page 5Linked to original sources
PubMed1978

Cyclic and pathologic changes of the mare endometrium as detected by biopsy, with a note on early embryonic death.

Normal histologic changes that occurred in concert with the ovarian cycle were evaluated. When combined with behavioral and physical findings, this evaluation enabled determination when there was synchrony between ovarian steroids (estrogen and progesterone) and their target tissues of endometrium. A system for classification as well as definitions of patterns types and degrees of severity of inflammatory and fibrotic changes was developed to facilitate a uniform system for description and communication. An attempt was made to relate the pathologic changes to their effect on fertility when fertility was defined as the ability to conceive, maintain, and deliver a live foal. This was done by dividing the types of endometrium into 3 categories, based on increasing degrees of extensiveness and severity of the various changes, and it was possible to show a high correlation of category to foaling rate. Embryonic and fetal loss from endometria with widespread periglandular fibrosis was observed. This was considered to be the major diagnosable cause of this type of reproductive failure.

Abortion, Veterinary↗
PubMed1975

Effect of exogenous progesterone on its endogenous levels: biological half-life of progesterone and lack of progesterone binding in mares.

The disappearance rate of progesterone from blood plasma of an ovariectomized mare was rapid and occurred in three phases. The half-life of the first component was 2-5 min and that of the second was 20 min; the half-life of the much slower third component was not measured. Progesterone, administered to ovariectomized and deeply anoestrous mares at the rate of 150 or 300 mg/day, maintained maximal peripheral levels of 6 to 8 ng/ml. Physiological levels were reached in 21 days using a dose of 150 mg and in 11 days with 300 mg daily. After withdrawal, circulating levels dropped rapidly. Blood plasma of mares appears to lack progesterone-specific binding proteins. It is concluded that the problem of habitual abortion and its treatment in mares need re-evaluation.

Animals↗
PubMed1975

The use of prostaglandin F2alpha-tham salt in mares in clinical anoestrus.

Seventy-three Standardbred and Thoroughbred mares in clinical anoestrus during the breeding season were treated with PGF2alpha. The mares were divided into four categories; foaling, barren, maiden and unknown. The response was consistent in all groups. Mares at Days 2 to 4 of dioestrus showed no decrease in plasma progesterone levels, and those at Days 6 to 8 showed a return of progesterone to baseline levels (less than 1 ng/ml) in 24 to 48 hr after treatment. Plasma progesterone levels returned to basal levels in 24 to 48 hr in 93% of mares; progesterone levels had not changed by 96 hr in 7% of the treated mares. Behavioural oestrus was detected in 71% of treated mares an average of 4-4 days after treatment, and ovulation occurred in 86% at an average of 8-9 days. Pregnancy occurred in 55-5% of the PGF2alpha-treated mares after an average of 1-7 services during the induced oestrus.

Anestrus↗
PubMed1975

Selected pathological changes of the mare uterus and ovary.

Focal enlargements of the uterus are palpable through the rectal wall and have various aetiology. Aspects of their diagnosis, possible pathogenesis, significance and treatment are presented. Lymphatic lacunae appear to be quite common in older mares and may occasionally give rise to large endometrial cyst, but more frequently cause widespread change throughout the uterine horns. Three unusual ovarian abnormalities are presented, a large, oestrogen-producing granulosa cell tumour, an oestrogen-producing large follicle in a 4-month-old filly, and an ectopic progesterone-producing adrenal structure bordering on neoplasia.

Animals↗
PubMed1975

Plasma progestagens in cyclic, pregnant and post-partum mares.

The pattern of plasma progestagen levels during the oestrous cycle was similar to that previously reported except for lower peak levels. The lack of significant difference (p less than 0-01) between CPBA and RIA values suggests that progesterone itself is the major component during the oestrous cycle. Progesterone levels during the first and second post-parturient oestrous cycles were similar to those observed during the cycle of the non-pregnant mare. During pregnancy there were two peaks of plasma progestagens. The first, which occurred during the 3rd month, coincided with high levels of PMSG and was probably produced by the endometrial cups or the secondary CL. The second peak occurred in the 11th month and probably represented the secretion of placental progestagens. At least two unknown progesterone (?) metabolites were present which cross-reacted in the CPBA and RIA systems and probably contributed to the high progestagen values obtained in late pregnancy when chromatography was excluded from the assay procedures. Progestagen levels dropped precipitously after parturition and was probably due to placental separation from the endometrium. The higher progesterone levels in the newborn foal and other evidence suggests that this hormone is produced by the fetal gonads.

Animals↗
PubMed1975

Androgens and oestrogens in normal and cryptorchid stallions.

Total androgens, testosterone and total oestrogens were measured in twenty-one intact, nine unilaterally cryptorchid, three bilaterally cryptorchid stallions and four geldings. Total oestrogens were significantly higher (P less than 0-005) and total androgens significantly lower (P less than 0-05) in the bilateral cryptorchid compared to other groups. There was a significant (P less than 0-025) day and night variation in total androgen levels. Thyroidectomized and intact animals showed a marked decrease in total androgen as well as testosterone levels during the winter period thus showing an effect of season on androgenic function of the testis. Disappearance rate of total and androgens following castration was extremely rapid and levels were undectable within 12 hr. Sexual stimulation appeared to increase total androgen levels. Testosterone, androstenedione, dihydrotestosterone, androstandiols, and androstenediol were identified in spermatic vein blood. Dihydrotestosterone was measured in fluid from the cauda epididymidis.

Androgens↗