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Biomedical subjects

K Kanazawa

Publications and source records attributed to K Kanazawa.

At least 325 records · Page 18Linked to original sources
PubMed1975

Experimental induction of colonic carcinomas in rats. Analysis of factors influencing upon the incidence.

A method to make a diverted segment of the colon keeping direct continuity to the main colonic lumen was introduced to study carcinogenesis in the colon of rats. This method was proved to be useful for analyzing several factors influencing upon cancerization in the colonic mucous membrane. Macroscopical colonic neoplasia were induced in nearly 80% of rats treated with N-methyl-N'-nitro-N-nitrosoguanidine introduced into the colonic lumen through the diverted segment. Neoplastic lesion of the mucous membrane developed mainly in the colonic segments which were in direct contact with intestinal content. The importance of intestinal content and colonic microflora was discussed and reviewed. One epithelial cell line was established from one intraperitoneal metastatic deposit of a huge colonic carcinoma induced by the carcinogen. This cell line has been maintained in tissue culture. The liver was susceptible to the carcinogen, and multiple cystic lesions were observed after intracolonic administration of the chemical.

Adenoma↗
PubMed1974

The effects of electrical stimulation of VL and sub-VL on muscle tonus.

VL and sub-VL were electrically stimulated at 1-mm intervals and the influence on three muscles (anterior tibial muscle, gastrocnemius muscle and soleus muscle) of the contralateral limb was studied by the method of RE-EMG. The effect of VL and sub-VL stimulation was examined on ether clonus as an indicator of hyperactive muscle, especially for spasticity. The results are summarized as follows: 1. Clonus was apparently suppressed by electrical stimulation in an area (F, 10.0 mm; L, 4.0 mm; D, from +2 to -2; there was especially marked suppression of clonus by stimulation in sub-VL. 2. On electrical stimulation of the lateral third of VL, hypertonicity of anterior tibial muscle (T), hypotonicity of gastrocnemius muscle (G), and also hypotonicity of soleus muscle (S), was observed on stimulation of the middle third, T, G, S, and of the medial third, no effect was observed. 3. Electrical stimulation of the anterior part of VL showed T, G, S, and electrical stimulation of the posterior part of VL showed T, G, S.

Animals↗
PubMed1970

Migration of asbestos fibres from subcutaneous injection sites in mice.

Crocidolite asbestos fibres, suspended in physiological saline, were injected subcutaneously into one or both flanks of 95 CBA/Lac female mice; 75 control mice received injections of saline only. Most animals were killed at chosen intervals of between 2 and 42 days after injection but some were left for longer periods of up to 623 days. At autopsy, many lymphoid and non-lymphoid structures were removed and examined for the presence of asbestos by the following techniques: haematoxylin and eosin staining followed by conventional and polarized light microscopy; Perl's stain; microincineration followed by phase-contrast microscopy; maceration with KOH followed by phase-contrast microscopy; and electron microscopy.A combination of haematoxylin and eosin staining and microincineration was found to be the most convenient and reliable method for demonstrating asbestos fibres in the tissues. Electron microscopy was essential for detecting very small fibres and for locating them to specific intracellular structures.The morphological findings indicate that some migration of asbestos fibres away from the initial site of injection takes place. Dissemination is usually along lymphatic pathways and fibres tend to accumulate in the lymphoid tissues, particularly in the regional (axillary) lymph nodes; smaller amounts were found in inguinal, mediastinal and lumbar nodes. The fibres were usually intracellular, lying inside the phagosomes of macrophages, but larger fibres weresometimes encountered lying free. Small numbers of fibres were seen in the spleen and also in non-lymphoid organs such as the liver, kidneys and brain-suggesting that some asbestos may enter the blood stream. There was no evidence of massive or selective spread to subserosal tissues in the thorax or abdomen, though trapping of asbestos fibres was observed in pleural "milky spots" in long-term survivors. The possible role of milky spots in the development of pleural plaques and mesotheliomata is discussed.

Animals↗