Ultrastructural changes in gonadotrophs after ovariectomy in female albino rats

Gonadectomy cells were studied with electron microscope 1-3 months after ovariectomy in female rats. One month after operation, the gonadotrophs showed variable number of tiny cytoplasmic vesicles scattered between secretory granules and mitochondria. These vesicles were shown to be dilated profiles of rough endoplasmic reticulum. The Golgi apparatus was prominent and demonstrated close to the nucleus. Two months after surgery, the gonadectomy cells showed larger vesicles with irregular outlines. The granules were apparently decreased as the average size of the vesicles was increased. Numerous signet ring cells were seen three months after ovariectomy. Each cell showed a giant vesicle at one side and a peripheral nucleus at the opposite side. The cytoplasmic rim at the cell periphery revealed variable sized granules, mitochondria and profiles of dilated rough endoplasmic reticulum. This study confirmed a proportional relation between the number and size of the cytoplasmic vesicles, and the duration of ovariectomy. Also, it was concluded that this surgery could influence the gonadotrophs by affecting some of their cytoplasmic organoids

Histological and histochemical studies on the effect of experimentally induced hyperthyroidism by l-thyroxine on the liver of the female albino rat

Eighteen female albino rats of an average weight 200 gm were used to study the histological and histochemical changes in the liver produced by experimentally induced hyperthyroidism. 12 animals were given a daily oral dose of 100 mu g L-thyroxine for 3 and 4 months. Whereas, 6 age-matched animals served as controls. Experimentally induced hyperthyroidism elicited marked histological changes in the liver that were more pronounced in animals with induced hyperthyroidism for 4 months. The Glisson's capsule was thickened. The central veins were congested and occasionally surrounded by mononuclear cellular infiltration. They were surrounded by increased collagenus fibers that extended around some adjacent hepatocytes. The blood sinusoids of the liver, especially those located in the subcapsular region, presented a very marked dilatation and congestion. Whereas, the hepatocytes, especially those located underneath the Glisson's capsule, were apparently markedly enlarged. This was confirmed by the morphometric study. Moreover, the number of binucleated hepatocytes were increased and occasional mitotic figures were observed. The enlarged hepatocytes presented an intense P.A.S. positive material in their cytoplasm, indicating probably an increase in their glycogen content. The hepatocytes in the peripheral parts of a few hepatic lobules showed vacuolation of their cytoplasm that appeared in both hematoxylin and eosin and P.A.S. stained sections, suggesting a fatty change. Whereas, the portal tracts were markedly enlarged and even extended between the hepatic lobules. They presented an intense mononuclear infiltration, many sections of bile ducts and widely dilated and congested blood vessels. Increased collagenous fibers were detected in the portal tracts that were surrounded by prominent and thick periportal collagenous fibers which extended to surround some adjacent hepatocytes. As regards to the histochemical study, the succinic dehydrogenase enzyme activity, compared to that of the control animals, showed an increased activity which was more marked in animals with induced hyperthyroidism for 4 months

Histological and histochemical studies on the effect of experimentally induced hypothyroidism by carbimazole on the kidney of the female albino rat

The present investigation comprised the study of the effect of experimentally induced hypothyroidism on the kidney of the female albino rats, with an average weight 200 g. Experimentally induced hypothyroidism was performed by giving 12 animals a daily oral dose of 2.4 mg carbimazole for 3 and 4 months, respectively. 6 age-matched animals were used as controls. The kidneys of the experimentally induced hypothyroid animals presented a significant decrease in the mean value of their weights, as well as marked histological changes in the renal corpuscles, proximal convoluted tubules, and the interstitial tissue of the kidney. These changes were more marked in animals with an experimentally induced hypothyroidism for 4 months. The histochemical changes in the kidney were more marked in animals with an experimentally induced hypothyroidism for 4 months. The succinic dehydrogenase enzyme activity was markedly increased in the lining cells of most of the proximal convoluted tubules. Moreover, the alkaline phosphatase enzyme activity was increased in the lining cells of most of the proximal convoluted tubules, especially those in the inner cortical region. Some proximal convoluted tubules in the outer cortical region showed a decreased alkaline phosphatase enzyme activity in their lining cells

Histological and histochemical studies on the effect of experimental unilateral complete ligation of the left ureter on both kidneys of the albino rat

This study was carried out on 50 male albino rats, with an average weight 200 g. They were divided into 2 equal groups. The first group was subjected to sham operation and served as a control group. Whereas, the second group was subjected to experimental complete ligation of the left ureter. Morphometric, histological and histochemical studies in both the obstructed and contralateral kidneys were performed at 1, 2, 7, 14 and 28 days after ureteric obstruction. From the results obtained, it could be concluded that experimental complete ureteric obstruction affected both kidneys. The obstructed kidney showed structural and functional enzymatic impairments with persistence of some intact renal tubules at 7 days following ureteric obstruction. By the 14th day, the obstructed kidney showed extensive tubular atrophy, together with an intense interstitial cellular infiltration and much increased collagenous fibers. On the other hand, the contralateral kidney revealed compensatory renal growth and increased enzymatic activity that could reflect structural and functional workload adaptation