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Biomedical subjects

K Frese

Publications and source records attributed to K Frese.

At least 55 records · Page 3Linked to original sources
PubMed1983

Pathogenesis of Borna disease in rats: immune-mediated viral ophthalmoencephalopathy causing blindness and behavioral abnormalities.

Borna disease virus is an unclassified agent that causes a rare but fatal encephalitis in horses in Germany. In experimental animals the virus causes acute fatal encephalitis in some instances and chronic encephalitis with abnormal behavior in others. In initial studies of the pathogenesis of the latter disease in rats, the virus was shown to replicate only in the nervous system, with the greatest concentration of infectivity in the cerebrum and eyes. Viral replication continued indefinitely in both newborn and adult rats. The adult animals developed self-limiting, necrotizing encephalitis in the cerebrum, with inflammation spreading to the retina. Inflammation receded after two months, however, with concomitant cessation of necrosis; static hydrocephalus was observed at this point. Levels of viral replication were unaffected by these changes. Rats became frenzied and aggressive during the encephalitic period but became permanently passive and inactive after inflammation receded. Infected neonates and immunosuppressed adults did not become ill. The frenzied behavior and subsequent blindness in immunocompetent adults were therefore attributed to a uniquely transient immunopathologic reaction targeted to centers in the limbic system and retinal neurons.

Animals↗
PubMed1981

Glomerular lipidosis in the dog.

With both light-microscopy and electron-microscopy, glomerular lipidosis in the dog appears in two forms which can freely pass into each other: 1. A nodular non-compressing form, and 2. and expansive compressing form. The focal areas are completely surrounded by a basal membrane. The covering podocytes are basically unchanged. The primary site of lipid deposition is the mesangial cell, not the endothelial cell.

Animals↗
PubMed1978

Genetics of susceptibility in the platyfish/swordtail tumor system to develop fibrosarcoma and rhabdomyosarcoma following treatment with N-methyl-N-nitrosourea (MNU).

About 7000 animals of 65 different genotypes of the xiphophorine fish were treated with the direct acting chemical carcinogen N-methyl-N-nitrosourea (MNU; 10(-3)M; four times for 1 hour in two week intervals), in order to find out whether the susceptibility for development of fibrosarcomas and rhabdomyosarcomas is directly related to the genotype. A genotype specific susceptibility was found, ranging from zero to about nine percent. The highest susceptibles were found in certain backcross hybrids involving P.variatus/X.helleri-hybrids and X.helleri, as the recurrent parent. These genotypes were further analysed. Both P.variatus and X.helleri, as werr as their F1 proved to be insusceptible; while from the three backcrosses, which were tested, namely the BC1, BC4 and BC15, both the BC1, and the BC4, were susceptible, but the BC15 was insusceptible. The results are interpreted on the basis of the assumption that the differential susceptibility is a function of the type of control of a tumor gene (Tu-Fi-Rh) endogenous to P.variatus and involved in development of fibrosarcomas and rhabdomyosarcomas. Accordingly, in P.variatus and in the F1 the Tu-Fi-Rh is controlled by repressing genes (R-genes) linked as well as non-linked to Tu-Fi-Rh; because simultaneous mutation of both R-genes following treatment with MNU is an extremely unlikely event, these genotypes have an extremely low susceptibility. By contrast, in the BC1 and the BC4 the non-linked R-genes become eliminated and only the linked R-gene remains for repression of Tu-Fi-Rh; this condition confers a high degree of susceptibility, because one single mutation may lead to impairment of the R-gene and to Tu-Fi-Rh-mediated formulation of fibrosarcomas and rhabdomysarcomas. In the BC15, furthermore, also the Tu-Fi-Rh has become eliminated, resulting in a loss of the susceptibility. The results suggest that in the xiphophophorine fish the susceptibility for responding to MNU-treatment with the development of fibrosarcomas and rhabdomysarcomas is related directly to the genotype.

Age Factors↗
PubMed1978

[Developmental studies on melanoma of the skin and mouth mucosa of dogs].

Progressive studies in dogs with skin and oral melanomas were undertaken to determine whether or not the WHO-classification of melanomas, which is based mainly on histological criteria, reflects sufficiently the biological behaviour of these tumours. Furthermore, some prognostic parameters, important in the prognosis of human malignant melanomas were tested with respect to their significance for canine melanomas. The paper deals with progressive studies in 182 dogs with surgically treated benign and malignant skin and oral melanomas. Parameters of the biological behaviour were the 2 years death rate and the median survival time. The melanomas were classified according to the recommendations of the WHO. Within 2 years after the first treatment five (5.7%) of 87 dogs with benign skin melanomas, 29 (65.9%) of 44 dogs with malignant skin melanomas and 44 (86.2%) of 55 dogs with malignant oral melanomas were killed because of recurrence or metastases or both. The median survival time of dogs with benign skin melanomas was more than 24 months, with malignant skin melanomas 8 months and with malignant oral melanomas 3 months. In dogs with large malignant skin melanomas the 2 years death rate was 100% with a median survival time of 4 months, whereas animals with small melanomas had a 2 years death rate of 54.3% and a median survival time of 12 months. The site of skin melanomas, sex and histological type of both skin and oral melanomas, however, had no significant influence on the course of the disease. Also, histological parameters, important in the prognosis of human malignant melanoma (rate of mitosis, size of nucleoli, pigmentation and vascular invasion), had no significant influence on the course of the disease.

Animals↗
PubMed1976

Aberrant nerve fibre bundles in the retina of the dog.

Systematic ophthalmoscopic examinations of 2511 Beagles, test animals in 72 long-term toxicological studies, showed archiform thin white stripes in the fundi of 98 animals (3.9%). The stripes occurred in one or both eyes in the non-tapetal fundus of the two lower quadrants. Examinations of the fundus of some dogs by fluorescence angiography and ophthalmoscopy with red-free light showed that these fibriform stripes were in the retina. Histological examination showed these stripes to be nerve fibre bundles (5-120 axons) lying at the ganglion cell layer. The ultrastructure of the fibres did not differ from that of the nonmyelinated neurites of the fibre layer. The stripes may be retinal nerve fibres with a normal structure but could be distinguished from fibres of the nerve fibre layer by their intraretinal location and by their course.

Animals↗
PubMed1974

Tumours of the skin.

Tumours occur more frequently in the skin than in any other part of the body. Epithelial tumours are described under the following headings: basal cell tumour, squamous cell carcinoma, papilloma, sebaceous gland tumour, tumour of hepatoid glands, sweat gland tumour, mixed tumour of apocrine sweat glands, carcinoma of apocrine sweat glands, tumour of hair follicle, and intracutaneous cornifying epithelioma. Tumours of the melanogenic system are divided into benign melanoma and malignant melanoma, the latter being subdivided into the following types: epithelioid, spindle cell, epithelioid and spindle cell, dendritic, and whorled.

Adenoma↗