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Biomedical subjects

K Lapis

Publications and source records attributed to K Lapis.

At least 163 records · Page 9Linked to original sources
PubMed1984

Appearance of fibronectin in putative preneoplastic lesions and in hepatocellular carcinoma during chemical hepatocarcinogenesis in rats and in human hepatomas.

The distribution of a high-molecular-weight glycoprotein, fibronectin (FN), was studied by immunohistochemical methods in putative preneoplastic lesions, as well as in fully developed hepatocellular carcinomas, formed in rats during chemical hepatocarcinogenesis, and in 10 human hepatomas. All but two preneoplastic lesions contained FN in their intercellular matrix. FN was present around groups of transformed liver cells, as well as on the surfaces and in the cytoplasms of certain cells. A similar, typically altered, distribution pattern was seen in the majority of the carcinomas studied. Six out of seven human hepatocellular carcinomas were found to contain FN. In three cases of cholangiocarcinoma, FN was, however, confined to the reactive stroma only. The presence of FN in hepatomas, which is in contrast to carcinomas of other organs, may serve as a marker for the demonstration of preneoplastic lesions of experimental carcinogenesis and for diagnostic differentiation of human hepatomas.

Adenoma, Bile Duct↗
PubMed1984

Alterations of markers during hepatocarcinogenesis in rats.

Fischer 344 male rats were treated with N-nitrosodiethylamine, and two weeks later promotion was effected by treatment with N-2-acetylaminofluorene for 14 days. At midpoint of the promotion protocol, one group of rats was subjected to partial hepatectomy (model A); others were treated with either carbon tetrachloride (model B) or thioacetamide (model C). Alterations in the activities of marker enzymes (glucose-6-phosphatase, gamma-glutamyl transpeptidase, cytochrome P-450, N-demethylase) during hepatocarcinogenesis were followed biochemically. The highest incidences of liver foci and of hepatocellular carcinomas were observed in model A, and these showed a good correlation with long-lasting elevated gamma-glutamyl transpeptidase activity. Analysis of the marker alterations suggests that there are three stages in hepatocarcinogenesis: (1) depression resulting from the toxic action of the initiator; (2) recovery and adaptation to cellular injury; and (3) long-lasting adverse alterations in the activities of the marker enzymes after promotion. The loss of certain non-histone proteins soon after promotion was also observed. Comparative studies of the individual actions of initiators and promoters on marker enzymes indicated that both contribute to the marker changes during hepatocarcinogenesis.

2-Acetylaminofluorene↗
PubMed1984

Further studies on the biochemical characterization of the MC-29 virus derived transplantable hepatoma (VTH). I. Binding of 3H-cortisol to cytoplasmic receptor and DNA.

The molecular mechanisms underlying the failure of steroids to stimulate glucose-6-Pase and arylhydrocarbonhydroxylase activities in the MC-29-virus-derived transplantable hepatoma (VTH) were investigated. Following cellular uptake of 3H-Cortisol, its subcellular distribution, binding to a specific cytoplasmic receptor and the interaction between steroid-bound receptor and DNA were compared in VTH and in normal chicken liver. No appreciable difference was observed either in 3H-Cortisol uptake or in binding to cytoplasmic receptors. However, compared with normal liver, only half as much hepatoma steroid receptor was able to interact with DNA at the protein/DNA ratio of 60. This reduced DNA binding of VTH 3H-Cortisol-receptor was irrespective of the source of DNA (VTH or liver). It is concluded that one of the causes for abnormal gene regulation in VTH may lie at the level of DNA-protein interaction.

Animals↗
PubMed1984

Effect of PGI2 in carbon tetrachloride-induced liver injury.

The hepatoprotective effect of prostacycline was studied after in vitro and in vivo CCl4 liver injury. It was found that PGI2 could partly restore the amino acid incorporation after in vitro CCl4 poisoning. In the in vivo system PGI2 was capable of decreasing the elevated SGOT levels and the accumulated triglyceride in the liver, and to increase hepatic glycogen content 24 hours after CCl4 injury.

Alanine Transaminase↗
PubMed1984

Polarization colours of collagen fibres: a sign of collagen production activity in fibrotic processes.

The maturation process of collagen fibres was investigated by the picro-sirius red/polarization light technique in experimental wound healing, in allyl-alcohol induced subacute and chronic liver fibrosis and in human biopsy material. Evidence was obtained that collagen fibres undergo a rapid maturation in fibrotic processes; the intensity of their birefringence increases and, at the same time, their polarization colour changes. Newly formed collagen fibres appear on the 4-6 mum thick sections in green polarization colour. Later, in a more mature stage, they became yellow, orange or red under crossed polaroids. The findings suggest that the simple picro-sirius red/polarizing light technique may be useful to form an opinion about the activity of the fibrotic process.

Animals↗
PubMed1984

Diffuse rheumatoid nodules in skeletal muscle in rheumatoid arthritis.

Rheumatoid nodule is an uncommon finding in rheumatoid arthritis (RA). A report is given on a case of RA which lasted for 15 years and nodules appeared diffusely in the skeletal muscles close to the fascia. These nodules had a histological structure similar to that found subcutaneously and a tendency to be confluent with colliquation necrosis resembling what was described in subpleural localization.

Arthritis, Rheumatoid↗
PubMed1984

Carcinogenesis studies on guppies.

Guppies (Lebistes reticulatus) were used as models for the screening of potentially carcinogenic substances. These fish, a simple, readily accessible type, are sensitive toward carcinogens. Using this model, we performed studies on the morphological effects of a few water-soluble chemicals. Guppies treated with diethylnitrosamine were used as positive controls. Changes were noted in the livers, and a few specific lesions occurred in their gastrointestinal tracts. Studies were also conducted with 10 other similar chemicals found in the human environment that have potential use in chemotherapy. Of these, the carcinogenic effect of N,N'-dinitrosopiperazine on fish was demonstrated. Some researchers think this compound is a derivative of the pesticide Triforine. Furthermore, 2 of the 10 chemicals intended for use in therapy proved to be potential carcinogens. Because these experiments with water-soluble substances are inexpensive and the test periods are short, the use of fish is considered more advantageous than is the use of rodents.

Animals↗
PubMed1984

[Significance of mineral substances in interstitial lung diseases].

Authors studied on 19 patients with interstitial pulmonary diseases bioptic material from the lungs gained with Hausser -needle especially for mineral components. With energy dispersive X-ray analysis (EDAX) in connection with electron microscopy exogen pigments were identified in every case. The pigment deposition proved to be the result of professional dust exposition. The inhaled dusts can be considered as etiologic factors if their source can be demonstrated unanimously, if other pathogens can be excluded and the characteristic tissue reactions can be demonstrated.

Adult↗
PubMed1983

The effect of E-N-trimethyl lysine (TML) treatment on the regeneration of bone marrow and intestinal mucosa in mice.

E-N-Trimethyl-lysine (TML) prevents the anemia caused by 5 Gy whole body irradiation of mice when applied simultaneously with irradiation in a dose of 100 mg/kg i.p. The number of splenic colonies increases significantly after TML treatment of the irradiated recipients. TML increased the proliferative activity of Lieberkühn's crypts in mice, especially after lethal whole body irradiation. The possibility of clinical use of TML is discussed.

Animals↗
PubMed1983

Transmission and scanning-electronmicroscopy of experimental liver metastases derived from intrasplenically growing primary tumor.

Liver metastasis formation from intrasplenically growing Lewis lung tumor was studied with transmission and scanning electron microscopy. Tumor cells arrested in the sinusoids formed desmosome-like junctions with endothelial cells and crossed the endothelial lining at intercellular gaps and by transcellular diapedesis. The metastatic foci had no newly formed vessels, and the stroma was provided by non-parenchymatous liver cells. Morphology suggested different outcome for tumor cell-host cell interactions at different stages of tumor growth. The host cell activity to destroy tumor cells was present only at the early stage but disappeared later, when the tumor cells were ready to phagocyte normal cells. The reason for this could be the immunosuppressive effect of the primary tumor. Results emphasize the importance to study metastasis formation in primary tumor-bearing hosts.

Animals↗
PubMed1983

Morphological investigations of mixed pituitary adenomas.

Thirteen pituitary adenomas were investigated by light and electron microscopy and in tissue culture. In all adenomas the production of growth hormone and prolactin was proved by endocrine symptoms of the patients and by laboratory tests. Histopathological findings were compared with culture characteristics. In 3 cases the adenoma consisted of three kinds of cell population, in 7 cases of two kinds, and in other 3 cases of one kind. In cases where 3 kinds of cell population were found, beside the granulated cells star-shaped forms without secretion granules could be observed. They probably corresponded to follicular cells. In three cases one single cell population was found. In these cases two different hormones might have been produced by one type of cell. These cells could be considered stem-like cellular elements or differentiated committed cells.

Adenoma↗