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Biomedical subjects

K Tajima

Publications and source records attributed to K Tajima.

At least 415 records · Page 23Linked to original sources
PubMed1987

Chondrocytes dedifferentiated by serial monolayer culture form cartilage nodules in nude mice.

Chondrocytes isolated from rabbit costal growth cartilage grew rapidly and expressed the differentiated phenotypes of chondrocytes in primary monolayer cultures. They had a typical polygonal shape, synthesized glycosaminoglycan (GAG) actively and responded to parathyroid hormone (PTH). However, during successive passages they lost the abilities to proliferate and express differentiated phenotypes. They changed from polygonal to fibroblast-like morphology during the third to fourth passage. Their GAG synthesis rapidly decreased in the 4th passage to 10% of that during primary culture. The increase in GAG synthesis and intracellular cyclic AMP induced by PTH also became smaller and were lost in the 4th passage. From these findings, cells in the 4th passage appeared to be dedifferentiated. However, subcutaneous transplantation of cells at the 5th passage into nude mice resulted in the formation of cartilaginous nodules. Moreover, cells isolated from these nodules and cultured in vitro had a typical polygonal shape and synthesized GAG actively and PTH increased their metachromatic matrix and intracellular cyclic AMP level. These findings suggest that chondrocytes that appear to be dedifferentiated after serial passages still have the potential to differentiate.

Animals↗
PubMed1986

Malignant lymphomas of the thyroid gland. Analysis of 79 patients with emphasis on histologic prognostic factors.

Prognostic factors in 79 patients with malignant lymphomas involving the thyroid gland were analyzed. These patients suffered from progressively enlarging goiter with over 6 months duration in 60% of patients. The age at operation ranged from 16 to 80 years (median, 58 years). Male to female ratio was 1:1.8. Serum tests for antithyroid antibodies were positive in 83% of the patients, who also showed histologic evidence of chronic lymphocytic thyroiditis. Histologically, 52 cases (66%) were germinal center cell tumors with follicular or follicular and diffuse pattern in 9 cases. By the Working Formulation, 5-year survival rate of immunoblastic type (IBL) (13%) was much poorer than those of intermediate (79%) and low grade cases (92%) (P less than 0.001). The cases of IBL usually had a goiter of short duration, and frequently presented as advanced disease.

Actuarial Analysis↗
PubMed1986

A possible model of hemoprotein-peroxide complexes formed in an iron-tetraphenylporphyrin system.

A ferric low-spin species with an anomalously small g3-g1 separation generated by the reaction of Fe(III)tetraphenylporphyrin with t-butylhydroperoxide in the presence of tatramethylammonium hydroxide was characterized by ESR spectroscopy. The reaction kinetics, investigated by monitoring ESR intensity, indicated that this low-spin complex is highly reactive and easily changed to non-heme type iron complexes. The rhombic parameters of this complex are very similar to those of heme-peroxide adducts such as [Fe(II)-hemoglobin-O2]- and [Fe(II)-horseradish peroxidase-O2]-.

Electron Spin Resonance Spectroscopy↗
PubMed1986

HTLV-I carriers among migrants from an ATL-endemic area to ATL non-endemic metropolitan areas in Japan.

The prevalence of antibodies against HTLV-I among Kyushu natives aged 16 to 39 years who moved from Nagasaki and Kagoshima prefectures to Aichi prefecture (a non-endemic area for ATL) was compared by their cities or counties of birth. The positive rate of anti-HTLV-I antibody was 2.4% (II/400) among Nagasaki natives, 6.4% (20/312) among Kagoshima natives and 4.0% (31/772) for both combined. There was a slight difference in the positive rate of anti-HTLV-I antibody between Kyushu natives from cities (3.3%) and from counties (4.5%). In county areas, the prevalence of anti-HTLV-I antibodies among migrants from areas of relatively higher mortality for malignant lymphomas (7.5%) was significantly higher (p less than 0.01) than among persons from lower mortality areas (1.9%). Most "positive" persons had moved from Kyushu to Aichi prefecture between the ages of 15 and 18 years. The results of the present study suggest that: there is a considerable number of HTLV-I carriers among Kyushu natives who have settled in ATL non-endemic areas, especially among those born in regions of Kyushu district which have a high mortality rate for malignant lymphomas; and that Kyushu natives who had settled in metropolitan areas might have been exposed to HTLV-I during childhood in their birthplace.

Adolescent↗
PubMed1986

Comparison of inhibition by a tumor promoter (12-O-tetradecanoylphorbol-13-acetate) of expression of the differentiated phenotype of chondrocytes in rabbit costal chondrocytes in culture with inhibition by retinoic acid.

Both retinoids and the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibit expression of the differentiated phenotype by rabbit costal chondrocytes in culture, as judged by morphological changes and decreased sulfation of glycosaminoglycans (GAG). However, the inhibition of the differentiated phenotype of chondrocytes in TPA-treated cells is restored by parathyroid hormone (PTH), while the inhibition by retinoids is not [Takigawa et al. (1982) Mol. Cell. Biochem. 42, 145-153; Takigawa et al. (1983) Cell Differ. 13, 283-291]. In the present study, we examined the difference between TPA-treated chondrocytes and retinoic acid-treated chondrocytes to determine the mechanism of the restoration of the differentiated phenotype in de-differentiated cells treated with TPA. PTH increased the activity of ornithine decarboxylase [ODC; EC 4.1.1.17], a rate limiting enzyme of polyamine biosynthesis, and proteoglycan synthesis in chondrocytes pretreated with TPA as well as in normal chondrocytes. The maximal stimulations of ODC activity and GAG synthesis were observed 4 h and 24-36 h, respectively, after addition of PTH. The dose-response curve for ODC induction by PTH was parallel to that of PTH-stimulated proteoglycan synthesis both in TPA-treated chondrocytes and in normal chondrocytes. PTH also increased the intracellular cyclic AMP level after 2 min in TPA-treated cells as in normal cells. Addition of dibutyryl cyclic AMP (DBcAMP) induced ODC and restored proteoglycan synthesis in TPA-treated cells. The dose-response curve for induction of ODC by DBcAMP was parallel to that of DBcAMP-stimulated proteoglycan synthesis in both TPA-treated chondrocytes and normal chondrocytes. On the other hand, the increases by PTH in the intracellular cyclic AMP level, ODC activity, and proteoglycan synthesis were inhibited in chondrocytes pretreated with a combination of TPA and retinoic acid as well as in those pretreated with retinoic acid alone. TPA stimulated the syntheses of DNA and RNA in chondrocytes but did not increase the cyclic AMP level or ODC activity. PTH and DBcAMP inhibited the syntheses of DNA and RNA both in TPA-treated cells and in normal cells. These results suggest that ODC induction mediated by elevation of cyclic AMP plays an important role in re-differentiation of de-differentiated cells pretreated with these agents.

Animals↗
PubMed1986

Renal hypouricaemia in a patient with 48,XXYY syndrome.

Studies on hypouricaemia observed in a patient with 48,XXYY syndrome revealed an abnormality in renal urate handling. His renal urate clearance was abnormally increased. Inosine administration and provocative tests using probenecid and pyrazinamide identified an isolated renal tubular abnormality with increased urate secretion. Since the serum urate in his brother with a normal sex chromosome constitution was also low, the association of renal hypouricaemia and 48,XXYY syndrome in this patient is probably coincidental. Although the brother was not investigated, these siblings may be a previously unreported case of familial hypouricaemia due to isolated renal hypersecretion.

Adult↗
PubMed1986

Idiopathic portal hypertension associated with Hashimoto's disease: report of three cases.

Three cases of idiopathic portal hypertension associated with Hashimoto's disease are described. All of the cases were middle-aged Japanese women showing splenomegaly, esophageal varices and pancytopenia in the absence of extrahepatic portal obstruction, and cirrhosis of the liver. Two patients were euthyroid with goiter, one of which revealed diffuse lymphocytic infiltration, obliteration of thyroid follicles, and fibrosis on histological examination of the thyroid; the third suffered from myxedema without goiter. Antithyroid microsomal antibody was positive in all patients and antithyroglobulin antibody was positive in none. These findings might imply an immunological role in the pathogenesis of idiopathic portal hypertension.

Female↗
PubMed1986

[Concentrations of cefmenoxime in human bone marrow blood and osseous tissue].

One gram of cefmenoxime (CMX) was administered to each of 10 patients by a one shot intravenous injection at the beginning of surgery. At 30, 60, 90, 120 minutes after the administration, concentrations of CMX in venous blood, bone marrow blood and bone tissue were assayed by the agar-well method. CMX was smoothly transmigrated after the injection from venous blood to bone marrow blood and bone tissue, and effective concentrations higher than MIC80 values were maintained for several hours. CMX, therefore, appears to be a useful drug for the prophylaxis and the treatment of postoperative infections.

Adult↗