Pathomorphological Changes in Organs of Rabbits with Experimental Colibacillosis

The aim of this research was to study pathomorphological alterations in the internal organs of rabbits through experimental reproduction of colibacillosis. The studies were conducted on 10 clinically healthy rabbits at the age of 3 months from a private farm. Animals were infected by intraperitoneal injection of a suspension of a pure culture of Escherichia coli isolated from a sand lizard. The disease of infected rabbits was accompanied by cachexia, dehydration and fever. The pathological process in the organism of infected animals was characterized by the violation of hemodynamics, the protein dystrophy of the parenchyma of liver, kidneys, myocardium and the formation of specific granulomas in the lungs and liver. The edema of reticular tissue and the hyperplasia of lymph nodes were observed in the organs of the immune system. The expressive edema of mucous membrane and submucosa, as well as alterative and necrotic processes were detected in the intestine.

Histological study of the drug PEG-Filstim sub-acute toxicity

One of the critical steps in development of safe and efficient drugs during their pre-clinical trials are toxicity studies. Therefore, the aim of our work was to study PEG-Filstim toxic effects on animal internal organs and tissues. Toxicity study of PEG-Filstim was performed in 50 white wild-type rats of both sexes with body weight of 170 to 230 g on daily (28 days) subcutaneous administration in the doses of 0.5, 1.0 and 2.0 mg/kg. In all groups of animals, after completing the experiment careful pathomorphologic and histological examination was performed. PEG-Filstim has been shown to possess no toxic effects on internal organs of laboratory rats and does not cause specific changes in the heart, kidneys and mucous coat of stomach on daily subcutaneous administration in the doses of 0.5, 1.0, and 2.0 mg/kg within 28 days. In the maximum applied dose of 2.0 mg/kg, the studied drug causes pronounced acute splenic hyperplasia, related to hyper-proliferation of the reticular tissue, leads to functional strain of the liver due to formation of hematopoietic foci in it, as well as impaired integrity of the respiratory epithelium and congestive signs in the lungs, swelling of the brain tissues, abnormalities in the gray matter structure and hyperemia of the brain vessels. These effects were not observed in the animals, to which the drug was administered in the doses of 0.5 and 1.0 mg/kg. Administration of PEG-Filstim (in all studied doses) results in increasing the size of the ankle joint in rats, which is related to hyper-proliferation of the reticular tissue, leading to bone defect formation in the form of perforation with subsequent filling the periosteum with reticular tissue and formation of hematopoietic foci within its boundaries.

DISTRIBUTION OF ADRENOCORTICOTROPHIC HORMONE-STIMULATED ADENYLATE CYCLASE IN THE ADRENAL CORTEX

SUMMARY The intra-adrenal distribution of adenylate cyclase was measured in microsections of guinea-pig and rat adrenals. Addition of α-adrenocorticotrophin-(1–24)-tetracosapeptide (α1–24ACTH) in vitro to sections of normal guinea-pig adrenals stimulated enzyme activity in glomerular—fascicular border zone tissue and reticular tissue. The intravenous injection of α1–24ACTH increased adenylate cyclase activity in sections of adrenal cortex from dexamethasone-treated guinea-pigs. Enzyme activity was enhanced in glomerular—fascicular border zone tissue, reticular and fascicular—reticular border zone tissue. In the rat, hypophysectomy reduced adrenal adenylate cyclase activity to undetectable levels within 48 h. Addition of α1–24ACTH to tissue sections in vitro augmented enzyme activity. Adenylate cyclase activity was also measured in homogenates of whole guinea-pig adrenal tissue. α1–24ACTH (10, 100 and 1000 ng/ml) stimulated basal enzyme activity, whereas porcine insulin (400 pg/ml and 4 ng/ml) was without effect. Insulin inhibited the stimulation of adenylate cyclase activity by α1–24ACTH at concentrations of 10 ng/ml and 100 ng/ml. At higher concentrations of α1–24ACTH, insulin was without effect.

Origin and Recovery of Colony-forming Units in Locally Curetted Bone Marrow of Mice

Histologic study of locally curetted bone marrow showed a sequence of blood clot formation, displacement of the clot by a primitive reticular tissue, and hematopoietic regeneration. Histologic regeneration of sinusoidal vessels, and recovery was incomplete 12 wk later with increased fat, residual trabecular bone, and cystic areas. Recovery of colony-forming units (CFU) paralleled hematopoietic cellular recovery and did not exceed levels of 70% of normal by 12 wk postcurettage. Transplantation of cureted and irradiated mice with T6T6 marker chromosomes demonstrated that cells with marker chromosomes migrated readily into irradiated marrow but were excluded from the curetted marrow for 2 wk after curettage. Three weeks after, curettage marker cells gained ready access to curetted marrow. The early exclusion but later appearance of transplanted marker cells was correlated with the early absence and later regeneration of sinusoidal vessels. The histologic and cytogenetic studies support the concept of a dependence of hematopoiesis upon a sinusoidal system with an appropriate marrow microenvironment. These studies support the concept of a local origin of marrow regeneration within curetted cavities but do not indicate whether the hematopoietic tissue originates from small numbers of residual CFU surviving curettage or from multipotential reticular cells. There was no evidence of a stimulatory effect upon uncuretted marrow by the action of curettage.

A Cerebral and Ocular Tumor of Reticular Tissue in a Horse

An intracerebral and intraocular neoplasm occurred in a 15-year-old horse. The horse presented with signs of a cerebral space-occupying lesion, blindness, and opacity of the vitreous body. There were a number of cell types within the well-defined tumor, some of which were multinucleate, and some apparently exhibited phagocytosis. The tumor was productive of reticulin fibres. The tumor was diagnosed as a microglioma, an unusual human tumor and one not previously reported in the horse. The intraocular metastasis of the tumor is unique.