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Biomedical subjects

A Nyska

Publications and source records attributed to A Nyska.

At least 127 records · Page 7Linked to original sources
PubMed1992

The effect of thionaphthene-2-carboxylic acid (TNCA) on bone structure in the rat: a histomorphometric study.

Thionaphthene-2-carboxylic acid (TNCA) has been shown to decrease osteoclast-mediated bone resorption in vitro and has shown efficacy in animal models of hypercalcaemia of malignancy. In this study, the effects of TNCA on the tibial proximal epiphysis and the sternum have been quantified by image analysis in rats administered the drug orally for 90 days at 75, 125 or 250 mg/kg/day. The amount of bone in the subepiphyseal area and sternum was increased in a dose-related manner. TNCA exerted a biphasic effect on the height of the epiphyseal plate. It was stimulatory at the low dosage and inhibitory at the high dose. This study constitutes the first of its kind to demonstrate the in-vivo effect of TNCA on the bones of rats.

Animals↗
PubMed1991

Protective effect of O-phenanthroline against mechlorethamine toxicity in the rat liver slice system and in the guinea pig skin.

The effect of O-phenanthroline (OP) on mechlorethamine hydrochloride (HN2) toxicity was studied in in vitro and in vivo experiments. Incubation of HN2 with the in vitro rat liver slice system resulted in leakage of alanine aminotransferase (ALT) in a time-dependent manner. Exposure of the slices to HN2 for 4 h caused 79.2% ALT leakage. In the presence of OP enzyme leakage was reduced to 28.7%. OP-induced protection was shown to be dose dependent. Other metal chelators such as dithiothreitol (DTT) and EDTA (ethylenediaminetetraacetic acid) had a weak effect on HN2 cytotoxicity. The protective activity of OP was also demonstrated in in vivo skin toxicity studies in the guinea pig. The ulcerative effect of topically applied HN2 was inhibited by OP even when applied 10 min following the alkylator. Histology of NH2-treated skin showed epidermal ulceration associated with a covering layer of encrusted exudate. However, only a slight diffuse acanthosis of the epidermal layer was observed when OP was applied for 10 min after the vesicant. It is suggested that OP may be used for the prevention of tissue damage caused by antineoplastic treatment with nitrogen mustard. It might also be employed in military medicine as an antidote to the chemical weapon sulfur mustard.

Animals↗
PubMed1991

Spontaneous ameloblastic fibro-odontoma in a female mouse.

A spontaneous ameloblastic fibro-odontoma is described in a 73-wk-old female mouse. The tumor was located in the molar mandibular region. The diagnosis was made on the basis of the histologic presence of odontogenic epithelial tissue embedded in mesodermal tissue resembling dental papilla, and containing in addition dentin and enamel. The positive reaction for keratin and vimentin confirmed the presence of ectodermal and mesodermal elements respectively in the tumor.

Animals↗
PubMed1991

Role of morphological methods in the analysis of chemically induced colon cancer in rats.

The role of selected histopathological methods was evaluated for the characterization of tumourous tissues resulting from chemically induced carcinogenesis in rats. Colon cancer was induced by treating rats with a direct carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), alone or with subsequent treatments with secondary bile acids. Morphological studies showed that the tumorigenic effect of MNNG resulted in changes in the shape of the crypts, disappearance of mucous (goblet) cells, and marked increases in the mitotic index, the size of nuclei and the number of aberrant nuclei. A significant number of lymphocytes infiltrated between the crypts and into their lumens. A sharp decrease in concentrations of neutral mucopolysaccharides and sulfomucins and an increase in the amount of vic-glycol groups and nonsulfated mucosubstances were demonstrated in tumourous epithelial cells. A moderate positive reaction to tissue polypeptide antibody was observed in these cells. The tumor-promoting effects of secondary bile acids were detected morphologically by an increase in the amount of connective tissue that infiltrated newly formed tumors. The increased number of micronuclei in otherwise histologically unaltered colon tissues adjacent to a tumor suggests that these regions represent a precancerous stage in the development of tumors. The important role of morphological methods in the evaluation of the effects of carcinogen and tumor promoters and in the detection of various phases in experimental carcinogenesis was discussed.

Animals↗
PubMed1991

Expression of HLA class I and class II in gastric carcinoma in relation to pathologic stage.

The expression of HLA class I and II antigens was studied in 41 patients with gastric cancer and in 2 normal stomachs. The normal gastric epithelia were diffusely stained for class I antigens. No staining was observed for class II. In gastric cancer an overall reduction in staining was observed, which was related to the degree of tumor penetration through the gastric wall. In tumors which penetrated the mucosa and submucosa only, 80-90% of tumor cells were stained for class I, as well as the normal areas surrounding the tumor. On the other hand, in tumors which penetrated through the organ to the fat, only 10-20% of cells were stained. Staining for class II was observed in only 12 cases, all of them advanced, with penetration to muscle or fat. No staining was observed in the normal areas surrounding the tumor. The importance of HLA antigens in immune surveillance is discussed.

Gastric Mucosa↗
PubMed1991

Population distribution profiles of the activities of blood alanine and aspartate aminotransferase in the normal F344 inbred rat by age and sex.

Data on the blood enzyme activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were collected from control male and female F344 rats participating in toxicity studies at 17, 30, 56, 80 and 106 weeks of age. The data were skewed to the right with significant deviation from normality. Applying the Box-Cox transformation, it was concluded that approximately normal distributions could be obtained by using the reciprocal transformation. In general, the males showed a greater degree of heterogeneity for both enzymes. Enzyme activities at 17 weeks were lowest for both ALT and AST. There was a high correlation between the activities of blood ALT and AST, with some animals showing dramatic transient increases. Significant differences among studies with respect to the enzyme activities in rats of the same age were demonstrated.

Aging↗
PubMed1991

Spontaneous uterine granular cell tumour in a Fischer 344 rat.

The microscopic features of a spontaneous uterine granular cell tumour in a Fischer 344 rat are described. The location of the tumour is novel for the rat. The neoplasm is characterized by the presence of cells with cytoplasmic granules which were PAS positive and diastase resistant. Electron microscopy and immunohistochemistry results are presented and the origin of the tumour is discussed.

Animals↗
PubMed1991

Hepatic and renal metallothionein induction in the rat and mouse after treatment with furosemide.

Induction of hepatic and and renal metallothionein by furosemide was studied in the rat and mouse. Treatment of mice with 200 and 300 mg/kg furosemide elevated hepatic metallothionein by 117% and 366%, while renal metallothionein was induced by 29% and 380%, respectively. In the rat the drug was less potent i.e. liver metallothionein was increased by 167% and 217% following injection of 300 and 400 mg/kg furosemide, respectively, whereas kidney was not significantly changed by this treatment. The mouse hepatic and renal metallothionein was identified as zinc-containing thionein by Sephadex G-75 gel filtration (Ve/Vo = 2.0). In both species maximal induction was observed 24 hours post exposure. However, the mouse hepatic and renal metallothionein content declined after additional 24 hours whereas the rat metalloprotein was not reduced even after 72 hours of treatment. It is suggested that alterations in metal homeostasis may be responsible for hepatic and renal metallothionein induction caused by furosemide.

Animals↗
PubMed1990

The effect of swimming on bone modeling and composition in young adult rats.

The purpose of this study was to investigate the adaptability of long bones of young adult rats to the stress of chronic aquatic exercise. Twenty-eight female Sabra rats (12 weeks old) were randomly assigned to two groups and treatments: exercise (14 rats) and sedentary control (14 rats) matched for age and weight. Exercised animals were trained to swim in a water bath (35 degrees +/- 1 degree C, 1 hour daily 5 times a week) for 12 weeks loaded with lead weights on their tails (2% of their body weight) (BW). At the end of the training period following blood sampling for alkaline phosphatase, all rats were sacrificed and the humeri and tibiae bones were removed for the following measurements: bone morphometry, bone water compartmentalization, bone density (BD), bone mineral content (BMC), and bone ions content (Ca, Pi, Mg, Zn). The results indicate that exercise did not significantly affect the animals' body weight, bone volume, or length and diameters. However, bone hydration properties, BD, bone mass, and mineralization revealed significant differences between swim-trained rats and controls (P less than 0.05). Longitudinal (R1) measurement was higher by 43% for both humerus and tibia, and Transverse (R2) relaxation rates of hydrogen proton were higher by 117 and 76% for humerus and tibia, respectively; fraction of bound water was higher by 36 and 46% for humerus and tibia, respectively. BD, bone weight, and ash were higher by 13%. BMC and bone ions content were higher by 10%, and alkaline phosphatase was higher by 67%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

The expression of HLA class I antigens in germ cell testicular cancer.

The expression of HLA class I antigens in testicular germ cell tumors (TGCTs) was studied by the immunoperoxidase technique. In the normal testicle, the interstitial cells of Leydig as well as most of the germ cells were significantly stained. In typical seminoma, 75% of the tumor cells in stage I and 30% in stage II were stained. In embryonal cell carcinoma, 25% of the cases in stage I and less than 10% of those in stage II were stained. Mature teratoma was stained in most of the cases, whereas in malignant teratoma only 35% of the cases showed some staining of the tumor cells. In mixed tumors each component displayed its characteristic staining pattern. The expression of class I antigens on tumor cells is required for immune recognition and lysis of the tumor by cytotoxic T-cells. The reduced expression of class I antigens that was related to histologic characteristics and stage suggests that some testicular tumors may escape immune surveillance and become biologically more aggressive.

Dysgerminoma↗
PubMed1990

Gingival hyperplasia in rats induced by oxodipine--a calcium channel blocker.

Oxodipine, a new calcium channel blocker, induced gingival hyperplasia in rats. This is the first time that a calcium channel blocker has been documented as resulting in gingival hyperplasia in rats. In contrast to diphenylhydantoin, the hyperplastic changes induced by oxodipine were not precipitated by any prior irritation. The histology consisted of purely fibroblastic proliferation without infiltrate of inflammatory cells.

Animals↗
PubMed1990

Drug-induced decrease of serum alanine and aspartate aminotransferase activity in the rat, as a result of treatment with oxodipine, a new calcium channel blocker.

Chronic oral administration of oxodipine, a new calcium channel blocker, resulted in a reduction in the blood enzyme activity of alanine and aspartate aminotransferase. The reductions were both time and dose related. The decline in enzyme activities was accompanied by microscopic hepatic changes, which in the opinion of the authors should have been associated with an increase in the enzyme activities of alanine aminotransferase and aspartate aminotransferase. The effect was only partially reversed one month after the cessation of oxodipine treatment.

Alanine Transaminase↗