Developmental studies on the kidneys of rabbits

The development of the rabbit's kidney was investigated during the pre and postnatal periods. The bilateral mesonephroi appeared in 11 days old fetuses as two masses bulging into the coelomic cavity; one on either side of the developing aorta. Each mesonephric blastema was composed of primitive tubules, corpuscle and duct; supported by vascularized mesenchyme and covered by the coelomic mesothelium. By the 14[th] day, brush border appeared in some mesonephric tubules. Once the metanephroi appeared; in 15 days old fetuses, degenerative changes began to occur in the mesonephroi. The latter were completely disappeared in fetuses of 22 days of age. In 15 days old fetuses, the uretric bud appeared in the center of the metanephric blastema. As the fetal age reached 17 days, this bud began to branch. At 20 days, metanephric corpuscles started to develop. Near the end of fetal life, marked maturation of some corpuscles was evident. By the 25[th] day, the proximal and distal tubules as well as the macula densa began to appear. In 27 days old, the renal pelvis, collecting tubules and the medullary rays became visible. Moreover, thick and thin segments of nephrons loop appeared in the medulla. In newly born rabbits, the production of new nephrons in the subcapsular zone persisted for 2 weeks. From 4 weeks and onward, the collecting tubules became lined by dark and light cells

Lingual papillae of one-humped camel [camelus dromedarius] histological, some hitochemical, and sem studies 1-circumvallate papillae

Histological, histochemical and morphostructural characteristics of the circumvallate papillae of 11 adult camel's tongues were studied using light and scanning electron microscope. The camel had 6-7 circumvallate papillae on each side of the torus linguae which appeared as circumscribed structures covered by keratinized epithelium and surrounded by deep trenches toward which the ducts of the glands converged and finally opened. Numerous blood vessels and fascicles of nerve fibers were closely associated with the glandular acini and ducts. The taste buds were distributed in the epithelium of the trench filling the border of the dorsal surface. The keratin layer covering the epithelium of the vallate papillae together with the glandular acini and ducts showed PAS, alcian blue and aldehyde fuchsin reactivities, while Best's carmine was negative throughout the whole layers. Clear positive Alk-Pase reactivity was localized in the basement membrane and basal cell layers of the epithelium. However, the activity of acid-pace and SDH was demonstrated in all epithelial layers, but the former enzyme was more concentrated in the superficial cell layers and the later in the basal cell layers. Moreover, moderate to strong enzymatic activities of Alk-Pase, acid-pase and SDH were observed in the associated glands

Pre and postnatal studies on the trachea of the one humped camel [Camelus dromedarius]

In the present work, the tracheal development of the camel was studied during the prenatal and postnatal life using different histological and histochemical methods

Developmental studies on the tongue of rabbits

The development of the rabbits tongue was investigated during pre and postnatal periods, using 20 fetuses 11-30 days of age as well as tongues of 15 rabbits aged 1-150 days

Effect of tyrosine on the pars distalis of the rabbits hypothesis

The present study was conducted on 36 Newzeal and white rabbits assigned into three age groups of 2, 3 and 4 months, 12 rabbits for each group of the same age [6 males and 6 females]. For each sex, 4 rabbits were given orally a single dose of L-tyrosine, 100 mg/kg body weight and the other two rabbits, were left as control. The treated groups revealed an increase in the amount, size and the secretory activity of somatotrophs, lactotrophs and LH gonadotrophs, in addition to a marked increase in the amount, size and the secretory activity of thyrotrophs, adrenocorticotrophs and FSH gonadotrophs during the second month of age. From the present results it could be concluded that tyrosine acts as a growth promoting factor and a hormonal inducing factor, it can be used in rabbits for enhancing the puberty of both males and females. It could be recommended that tyrosine can be used on a large scale for regulating the reproductive cycle of males and females in large animals

Histological and some histochemical studies on the uropygial gland of young and mature pigeons

A total of 20 pigeons at 3-6 weeks and 5-10 months of age were used to study the histological structure of the uropygial gl and and its content of some carbohydrates, lipids and enzymes

On spermatogenesis, numbers of Sertoli cells and Leydig cells in stallions as modulated by age and season

The study used 56 testes collected from 28 Arab and native stallions [3-18 years] during a complete annual cycle. The consequences of seasonal and age-related changs in parenchymal weight and in numbers of spermatogonia, young and old primary spermatocytes, round spermatids, Sertoli cells and Leydig cells were evaluated. There were statistically significant seasonal and age effects on parenchymal weight, numbers of Sertoli cells, Leydig cells and spermatogenesis. Seasonal changes in the above testicular parameters were maximal in spring and winter, followed by summer, then reaching their minima in the autumn. The highest values for these criteria were reached by stallions of 6- <13 years, whereas the lowest values were observed later in life. Neither age nor season influenced tlie diameter of Sertoli cell nuclei, Leydig cell or leydig cell nuclei. The mechanisms by which the numbers of both somatic testicular cells fluctuate with the yearly reproductive cycle of the stallion were discussed. Evidence from the present results revealed that numbers of Sertoli cells, germ cells and parenchymal weight were interrelated. Numbers of spermatogonia, Sertoli cells and Leydig cells accounted for 59%, 58% and 48% of the variation in parenchymal weight, respectively. The relationships existed between the number of either of the two somatic testicular cells and spermalogenesis were also scrutinized. The present results emphasize the importance of age and seasonal changes in numbers of Sertoli cells and Leydig cells on regulation of stallions spermatogenesis