Dominic Oduor-Okelo

Plasma Testosterone in Trypanosoma Congolense-Infected Toggernburg Goats

Trypanosomiasis induces histological testicular degenerative changes leading to suppression of spermatogenesis in goats and laboratory animals. We present evidence associating these changes with trypanosome-induced endocrine dysfunction. Toggenburg goats were infected with approximately 100,000 trypanosomes. They were bled every 2 days, and the plasma testosterone was analyzed by radioimmunoassay. Testes were perfused with and fixed in Bouins fixative for histological evaluation. The infected plasma samples showed depressed testosterone levels with episodic peaks reduced in both amplitude and frequency. Histological characteristics of the testicular and epididymal tissues revealed aspermic tubules and epididymides and desquamation of the tubular germinal epithelia. These testicular degenerative changes may be partly due to the depressed plasma testosterone levels.

IN VIVO AND IN VITRO EFFECTS OF GRADED DOSES OF THE PESTICIDE HEPTACHLOR ON FEMALE SEX STEROID HORMONE PRODUCTION IN RATS

Adult female Sprague-Dawley rats were injected with corn oil or 5 mg, 20 mg, 25 mg or 30 mg per kg body weight of heptachlor solution every other day for up to 18 days. The rats were killed at the end of the experimental period, and blood samples were assayed for progesterone and oestrogen by radioimmunoassay. Ovarian cells from the rats were isolated and incubated either on their own, or in the presence of LH or FSH, and production of progesterone and oestrogen determined. Control incubations consisted of cells from corn oil-treated rats. The latter were also incubated on their own or in the presence of LH or FSH. Heptachlor significantly suppressed blood progesterone and oestradiol levels (P < 0.05 to P < 0.001), the degree of suppression depending on the dose and the stage of the oestrous cycle in which samples were obtained. Production of oestradiol by ovarian cells from heptachlor-treated rats was lower than for corn oil-treated controls. Cells from rats treated with low doses of heptachlor (5 mg per kg body weight) showed an increased production of progesterone, while high doses (> 20 mg per kg body weight) suppressed production.

Morphological characterization of the seminiferous cycle in the goat (Capra hircus): A histological and ultrastructural study

The cycle of spermatogenesis/seminiferous cycle was investigated in the goat testis using both light and electron microscopy techniques. Using the various cell associations and the accompanying changes in spermatid shape and location, the cycle was divided into eight (8) successive stages. The cycle began with the accomplishment of spermiation (stage 1) and ended with apical migration and close attachment of late maturation phase spermatids at the Sertoli cell apex accompanied by adluminal retention of residual bodies with dense staining inclusions (stage 8). The early stages of the cycle (stages 1-4) were therefore characterized by the presence of only one generation of spermatids, the second one appearing only after the division of secondary spermatocytes in stage 4. Consequently, stages 5-8 had two generations of spermatids; Golgi or cap phase as well as maturation phase spermatids. Although stages 5 to 7 appeared as distinct entities, stages 6 and 7 were rather short-lived and considered as continuations of stage 5. Therefore, the 8 stages of the cycle in the goat were further condensed into 6 main divisions. The duration of each stage was estimated by the frequency of occurrence in sections. Among these, stage 1 had the highest frequency (34%) followed by stages 5-7 (27%). Stages 8 and 4 had the shortest frequency (up to 9%) while stages 2 and 3 had 13% and 12% respectively. These results indicate that, like most domestic species, goats have a cycle of 8 stages with 6 main divisions, the longest being stage 1.

Effects of graded doses of the pesticide heptachlor on body weight, mating success, oestrous cycle, gestation length and litter size in laboratory rats

Adult female Sprague-Dawley rats were injected with 5 or 20 mg/kg body weight heptachlor solution every other day for up to 18 days. They were weighed every day and the stage of oestrus determined by vaginal smears. One experimental group was mated and pregnancy characteristics studied. Heptachlor affected body weights, cycle patterns, length of gestation period and litter sizes in a dose-related manner. At a dose of 20 mg/kg body weight, heptachlor caused a significant decrease in average body weight (P < 0.01), disrupted and/or prolonged oestrous cycles, decreased mating success (P < 0.001), slightly increased gestation length (P < 0.05) and decreased litter size (P < 0.01).

Histochemistry of the duodenal glands of the cat and horse.

The duodenal glands of cat and horse were studied using PAS, Alcian blue, dialysed iron, aldehyde fuchsin-Alcian blue and high iron diamine stains. It was found that the duodenal glands of the horse reacted positively to Alcian blue, dialysed iron stains and also took the Alcian blue stain in the combined aldehyde fuchsin-Alcian blue and high iron diamine-Alcian blue stains. Those of the cat gave negative results. These results suggest the presence of acidic groups in the mucosubstances secreted by the horses duodenal glands. A suggestion is put forward on the strength of the high iron diamine-Alcian blue combined stains that the acidity is due to the presence of carboxyl groups. It is suggested that the acidity may be significant in either cellulose metabolism or the digestion of the bacterial microflora from the stomach of herbivores.

Morphology of a Six-Legged Goat With Duplication of the Intestinal, Lower Urinary, and Genital Tracts

An adult female goat with rare malformations, which consisted of duplication of the intestinal, lower urinary, and genital tracts as well a pair of parasitic appendages, is presented.

The interhemal membrane of the spotted hyena: An immunohistochemical reappraisal

On the basis of specific immunohistochemical staining for vimentin and cytokeratin, we conclude that in the mature placenta of the spotted hyena the interhemal membrane is haemomonochorial rather than endotheliochorial, as in other carnivores. We concur that the intrasyncytial laminae are remnants of the maternal endothelial basal lamina.

Ultrastructural study of the testis of non-breeding naked mole-rat (Heterocephalus glaber, Ruppell)

The testicular structure of the wild caught naked mole rat was studied. It comprises of a large volume of lipid-rich interstitial cells of Leydig among which are few scattered seminiferous tubules. In addition, the interstitial cells possess elongated mitochondria and vast network of smooth endoplasmic reticulum (sER). The Golgi apparatus (GA) apparently is not conspicuous or well developed. All stages of spermatogenesis occur in the seminiferous tubules although the mature forms (secondary spermatocytes, spermatids and spermatozoa) are few. Sertoli cells show an irregular nucleus, mitochondria oriented perpendicular to the basement membrane, a vast network of endoplasmic reticulum with sER as the predominant form and lipid droplets. The ultrastructural features of Leydig cells seem to suggest a steroidogenic capacity although the vast accumulation of lipid droplets may imply impaired utilisation of cholesterol reservoir as a result of pituitary hormonal imbalance or (and) the local paracrine influence by Sertoli cells. The cause of slow-down in spermatogenesis is still unclear but may also be under the influence of pheromonal cues or the local paracrine control. Sertoli cell features point towards a role of synthesis and secretion.

Uterine gland microstructure in the pregnant and the non-pregnant lesser galago (galago senegalensis)

La histologia y ultraestructura de las glandulas uterinas de la galago menor (Galago senegalensis) fueron estudiadas en seis ejemplares (5 prenadas y 1 no prenada). Una parte de las glandula se fijo con Bouin y otra con glutaraldehido al 2,5% en tampon cacodilato 0,1 M. Una vision general de los principales resultados revelo que las glandulas uterinas en el utero no gestante son rudimentarias y escasas dentro de la mucosa. Al principio de la prenez (primer trimestre) las glandulas uterinas aparecen en racimos. En la ultima etapa de la prenez (tercer trimestre) las glandulas uterinas aparecen opuestas a las vesiculas corionicas. En las ultimas etapas de gestacion el epitelio glandular materno consiste principalmente en epitelio cilindrico simple. Las celulas tenian abundantes cisternas aplanadas en el reticulo endoplasmico rugoso, por lo general con una orientacion apico-basal. Sus nucleos tenian abundante eucromatina en relacion con la cantidad de heterocromatina. Tambien tenian un aparato de Golgi prominente bastante caracteristico de celulas que sintetizan proteinas. El plasmalema basal fue rechazado en repliegues que psoeen el efecto de aumentar el area de superficie a traves del cual los nutrientes podrian pasar desde la circulacion materna y son secretadas por las celula como histiotrofo. Hipertrofia fisiologica e hiperplasia de las glandulas uterinas se observaron con el avance de la prenez.

Daytime variations of serum testosterone and luteinizing hormone in captive thick-tailed bush babies (Galago garnetti)

Mean daytime serum levels of testosterone (T) and luteinizing hormone (LH) were determined in eight male thick-tailed bush babies at different times of the day by radioimmunoassay and leydig cell bioassay respectively. Blood samples were obtained twice a week from each animal at different times of the day between 08:30 and 16:00. This was carried out for a period of eight weeks. There was significantly higher mean serum T levels in the morning compared to evening hours (p<0.05). There was no significant variation in mean serum LH levels, and no significant correlation between serum T and LH levels.