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Biomedical subjects

F Okada

Publications and source records attributed to F Okada.

176 records · Page 10Linked to original sources

Plasma guanosine 3',5'-monophosphate responses to the cold pressor test in patients with vibration disease.

Plasma cyclic guanosine 3',5'-monophosphate (cyclic GMP) levels were determined during the cold pressor test (CPT) in 10 normal volunteers and 39 patients with vibration disease. The CPT caused no significant increase in plasma cyclic GMP in the controls. There was a sharp rise in plasma cyclic GMP during and after the CPT in patients with vibration disease. This increase was suppressed by simultaneous injection of phentolamine or atropine. In patients who had been treated with kallidinogenase or nicametate citrate for 3-6 months, the CPT caused no significant increase in plasma cyclic GMP. In 1 patient the plasma cyclic GMP was suppressed by dihydroergotamine. From these findings it is very likely that cholinergic or alpha-adrenergic receptor responses are enhanced in patients with vibration disease.

Adult↗

Unsaturated fatty acid feeding prevents the development of acute hepatitis in Long-Evans cinnamon (LEC) rats.

To investigate the effects of dietary alpha-linolenic acid (18:3, n-3; alpha-LNA) and linoleic acid (18:2, n-6; LA) on the development of hereditary hepatitis, we compared incidences and grades of acute hepatitis between the Long-Evans cinnamon (LEC) rats fed with safflower oil-supplemented diet and perilla oil-supplemented diet. Both safflower and perilla oil supplemented diets reduced the incidence of hepatitis and significantly prolonged its onset as compared to the non-supplemented conventional diet. No significant difference was observed between safflower and perilla oil diets in the rats of incidence of hepatitis. At the age of 16 weeks, just before the onset of hepatitis, serum levels of transaminase (AST, ALT) and concentration of copper in rats fed with both test diets were significantly reduced as compared with that of rats fed alpha-linolenate and linoleate have an inhibitory effect on the development of hepatitis in LEC rats due to the prevention of serum copper elevation.

Acute Disease↗

Decreased expression of HSP47 in highly malignant mouse fibrosarcoma.

HSP47, a heat shock-inducible glycoprotein of M(r) = 47,000, is assumed to be a molecular chaperone specific for collagen. In addition to its stress inducibility, HSP47 has transformation-sensitivity; that is, the synthesis of HSP47 decreases after malignant transformation. The expression of several HSPs in mouse fibrosarcoma, QRsP-1 and QRsP-4 were examined. HSP47 expression was weaker in the highly malignant QRsP-4 than in the weakly malignant QRsP-1, whilst HSC70 expression was similar in both cell lines. These findings suggested an important role of HSP47 as a marker of tumour malignancy of QRsP cell lines.

Animals↗

Enhancement of tumor associated antigen expression during the regression phase of xenogenized tumor cell growth in vivo.

Rat fibrosarcoma cells infected with Friend leukemia virus (FV-KMT-17) grow for a short time and then regress spontaneously in syngeneic hosts. This regression was caused by immunological mechanisms, because the tumor cells were renogenized. In this study, we have tried to find out whether tumor-associated antigen (TAA) expression in these xenogenized tumor cells can be modulated by xenogenization. FV-KMT-17 cells (1 x 10(7)), which were subcutaneously transplanted into ten rats, spontaneously regressed after temporary growth. All rats which rejected FV-KMT-17 cells showed strong resistance to rechallenge with KMT-17 (1 x 10(6)) cells. To reveal the chronological modulation of TAA and virus-associated antigen (VAA), a single-cell suspension was obtained from the subcutaneous tumors and expression of these antigens was chronologically measured. TAA, termed CE7 antigen, was examined by anti-CE7 monoclonal antibody (MoAb) and VAA was examined by anti-FK1 MoAb which recognizes the FV env gene product (gp 70). Expression of VAA was not modulated through either the progression or the regression phase, but expression of TAA was strongly enhanced in the regression phase. These results show that enhancement of TAA expression occurs during the regression phase of FV-KMT-17 growth in vivo and that TAA-expressing cells may stimulate anti-tumor immunity, resulting in acquisition of resistance against parental KMT-17 cells.

Animals↗

The LEC (Long-Evans Cinnamon) rat as an animal model for bilirubin-induced tooth pigmentation.

The LEC (Long-Evans Cinnamon) rat is well known as a useful animal model for hepatic disease. We noticed the green pigmentation in incisors 2-3 weeks after acute hepatitis accompanied by severe jaundice. This study was undertaken to elucidate the cause of this phenomenon. Half of the pigmented teeth were examined by histopathological analysis and microradiographic analysis. Pigmentation was observed as a green stripe that ran parallel to the incremental line in the dentine. The microradiographic analysis disclosed enhanced permeability of the pigmented area as compared with other areas. The rest of pigmented teeth were dried, powdered and bilirubin was extracted with chloroform /methanol/acetic acid, 30:10:0.5; v/v under sonication. After centrifugation, the supernatant was collected and evaporated. The residue was dissolved in chloroform and its absorption spectrum measured after diazo reaction to reveal the presence of bilirubin. The spectral characteristics indicated the presence of bilirubin in the pigmented teeth. Thus, the LEC rat may be useful animal model for bilirubin-induced tooth pigmentation.

Animals↗