PubMed Health⌕ Search

Biomedical subjects

M Rosenbruch

Publications and source records attributed to M Rosenbruch.

31 records · Page 2Linked to original sources
PubMed1989

Carcinogenicity studies on natural and man-made fibres with the intraperitoneal test in rats.

Female Wistar rats were injected intraperitoneally (i.p.) with a suspension of 11 fibrous and 3 granular dusts. A dose of 0.25 mg actinolite or UICC chrysotile induced tumours of the peritoneum in more than 50% of the animals. Even 0.05 and 0.01 mg proved to be carcinogenic, although no adhesions of the abdominal organs could be observed. The findings are in conflict with the hypothesis that a scar is always the morphological precondition for the development of an asbestos-induced tumour. Actinolite injected i.p. in a solution of polyvinylpyridine-N-oxide gave a lower tumour incidence than when suspended only in saline, possibly due to inactivation of the fibre surface. Persistent glass fibres were less effective than actinolite having a similar fibre size distribution. On the other hand, relatively thick basalt fibres and ceramic fibres gave higher tumour incidences than expected. Wollastonite fibres were not carcinogenic, probably because of their low durability. Large amounts of polyvinylchloride, alpha-ferric oxide hydrate and wood dust also led only to adhesions of the abdominal organs and fibrosis; a definite carcinogenic effect was not detected.

Animals↗
PubMed1985

Intimal asteroid bodies in horses: light and electron microscopic observations.

The morphology of asteroid bodies in equine arteries is demonstrated by light microscopy as well as by scanning and transmission electron microscopy combined with chemical analysis. Asteroid bodies first occur in horses at four weeks of age in all investigated tissues except the esophagus and always are located in the subendothelial space. The number, shape, ultrastructure and chemical composition of asteroid bodies differ markedly--depending on the age of the horse. Asteroid bodies are round and smooth in foals, but are shaped irregularly and have several projections and marked stratified calcification in adult horses. Asteroid bodies probably originate from smooth muscle cells. No direct etiological connection between asteroid bodies and migrating Strongylus vulgaris could be verified.

Aging↗
PubMed1984

[Hypophyseal adenocarcinoma in a horse. A case study].

The paper presents the case-history of a 5-year-old pony suffering from an adenocarcinoma which proceeded from the pars intermedia of the pituitary gland. Neurological and patho-morphological findings are reported.

Adenocarcinoma↗
PubMedDate not supplied

Altered p53 expression in early stages of chemically induced rodent hepatocarcinogenesis.

Most available data on the involvement of p53 in rodent carcinogenesis are based on results of the end point of chemically or virally induced carcinogenesis, i.e., tumors. To investigate the role of altered p53 expression in early stages of rodent hepatocarcinogenesis in a systematic way, we treated male Wistar rats for 6 wk, for 13 wk, and for 6 wk followed by a 7-wk recovery period with chemicals classified as genotoxic (200 ppm acetylaminofluorene [AAF], 100 ppm N-nitrosomorpholine [MMN], 200 ppm benzo(a)pyrene), as tumor promoters and carcinogenic in experimental animals (5 ppm ethinylestradiol, 500 ppm phenobarbitone, 3,000 ppm clofibric acid), as carcinogenic in animal experiments (600 ppm thioacetamide), as noncarcinogenic (200 ppm thyroxine), and as tumor promoters in experimental animals (20,000 ppm tryptophan, 120,000 ppm fructose). Immunohistochemical assessment of altered p53 expression on liver sections with polyclonal serum (CM5) resulted in positive staining in 17/21 benzo(a)pyrene-, 1/18 thioacetamide-, 2/21 clofibric acid-, 2/21 phenobarbitone-, 7/19 ethinylestradiol-, 1/21 tryptophan-, 3/19 thyroxine-, and 1/21 fructose-treated rats and in 2/19 controls. These data support earlier results obtained from analogous investigations with a high incidence of altered p53 expression after NNM and AAF treatment. Thus, altered p53 expression appears to be an early and frequent event in rodent carcinogenesis induced by genotoxic chemicals in contrast to most epigenetically acting chemicals.

Animals↗
PubMedDate not supplied

[Toxicity studies of the incubated chicken egg. With special reference to the extra-embryonal vascular systems].

The use of the incubated chicken egg as a test system to evaluate the effects of hazardous substances is reported. Several different methods to carry out toxicological as well as teratological studies are mentioned. Experimental toxicity testing and basic pathology studies on the extra-embryonal blood vessel systems of the chick embryo (yolk sac system and chorio-allantoic membrane) are described in detail. In this field, the application of the yolk sac system has some advantages compared with the chorio-allantoic membrane. Finally, the use of so-called "alternative methods" and the replacement of the Draize-test and LD50- studies are discussed.

Allantois↗