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Biomedical subjects

S Fujiwara

Publications and source records attributed to S Fujiwara.

At least 415 records · Page 23Linked to original sources

Identification of mammalian aminotransferases utilizing glyoxylate or pyruvate as amino acceptor. Peroxisomal and mitochondrial asparagine aminotransferase.

The subcellular distribution of asparagine:oxo-acid aminotransferase (EC 2.6.1.14) in rat liver was examined by centrifugation in a sucrose density gradient. About 30% of the homogenate activity after the removal of the nuclear fraction was recovered in the peroxisomes, about 56% in the mitochondria, and the remainder in the soluble fraction from broken peroxisomes. The mitochondrial asparagine aminotransferase had identical immunological properties with the peroxisomal one. Glucagon injection to rats resulted in the increase of its activity in the mitochondria but not in the peroxisomes. Immunological evidence was obtained that the enzyme was identical with alanine:glyoxylate aminotransferase 1 (EC 2.6.1.44) which had been reported to be identical with serine:pyruvate aminotransferase (EC 2.6.1.51) (Noguchi, T. (1987) in Peroxisomes in Biology and Medicine (Fahimi, H. D., and Sies, H., eds) pp. 234-243, Springer-Verlag, Heidelberg). The same results as described above were obtained with mouse liver. All of alanine:glyoxylate aminotransferase 1 in livers of mammals other than rodents, which cross-react with the antibody against rat liver alanine:glyoxylate aminotransferase 1, had no asparagine aminotransferase activity.

Animals↗

Brain metastasis from urachal carcinoma.

A case of brain metastasis from urachal carcinoma is reported. Originally the source of the tumor was unknown. Histologic diagnosis of resected specimen was adenocarcinoma. Later removal of urachal carcinoma with partial resection of the bladder revealed adenocarcinoma identical to that of the brain tumor.

Adenocarcinoma↗

A short-lived nuclear phosphoprotein encoded by the human ets-2 proto-oncogene is stabilized by activation of protein kinase C.

The human ets-2 gene is a homolog of the v-ets oncogene of the E26 virus and codes for a 56-kilodalton nuclear protein. The ets-2 protein is phosphorylated and has a rapid turnover, with a half-life of 20 min. When human lymphocytic CEM cells were treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), the level of the ets-2 protein was quickly elevated 5- to 20-fold. This effect of TPA was mimicked by a synthetic diacylglycerol, 1-oleoyl-2-acetyl glycerol, and was blocked by the protein kinase C inhibitor H7, indicating that protein kinase C is involved in the induction. The increase in the ets-2 protein was due to stabilization of the protein, because the protein had a half-life of more than 2 h in the presence of TPA and the ets-2 mRNA level did not increase significantly upon TPA treatment. The protein synthesis inhibitor cycloheximide enhanced the effect of TPA on the ets-2 protein and could itself slow turnover of the protein. Properties of the ets-2 protein, such as nuclear localization, phosphorylation, rapid turnover, and response to protein kinase C, indicate that this protein belongs to a group of oncogene proteins which are generally thought to have regulatory functions in the nucleus (e.g., myc, fos, myb, and p53). Our results suggest that protein kinase C, either directly or indirectly, regulates the level of the ets-2 protein by posttranslational mechanisms.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

c-myc can induce expression of G0/G1 transition genes.

The human c-myc oncogene was linked to the heat shock-inducible Drosophila hsp70 promoter and used to stably transfect mouse BALB/c 3T3 cells. Heat shock of the transfectants at 42 degrees C followed by recovery at 37 degrees C resulted in the appearance of the human c-myc protein which was appropriately localized to the nuclear fraction. Two-dimensional analysis of the proteins of density-arrested cells which had been heat shock treated revealed the induction of eight protein species and the repression of five protein species. All of the induced and repressed proteins were nonabundant. cDNA clones corresponding to genes induced during the G0/G1 transition were used as probes to assay for c-myc inducibility of these genes. Two anonymous sequences previously identified as serum inducible (3CH77 and 3CH92) were induced when c-myc was expressed. In response to serum stimulation, 3CH77 and 3CH92 were expressed before c-myc mRNA levels increased. However, in response to specific induction of c-myc by heat shock of serum arrested cells, 3CH77 and 3CH92 mRNA levels increased after the rise in c-myc mRNA. Therefore, we hypothesize that abnormal expression of c-myc can induce genes involved in the proliferative response.

Animals↗

The distribution and structure of FTS immunoreactive cells in the thymus of the mouse.

The intrathymic distributions of facteur thymique sérique (FTS)-containing cells and Ia-expressing cells were examined by a double immunofluorescence technique in C57BL/6 mice of various ages. In the thymic medulla of all the mice examined, there were both FTS-immunoreactive cells and Ia-immunoreactive cells. The former cells, epithelial in nature, extended elongate cytoplasmic processes, while the latter were connected with each other by their spiny processes. The FTS-immunoreactive epithelial cells were all Ia-negative. The FTS-immunoreactive cells and Ia-immunoreactive cells were located in close proximity to each other. The cortex of the adult mice contained no FTS-immunoreactive epithelial cells. The cortex of the newborn and old mice, however, contained scattered FTS-immunoreactive epithelial cells with processes. FTS-immunoreactive cells in the cortex of the old mice possessed Ia-immunoreactive partner cells, while those in the cortex of newborn mice did not. In the marginal zone of the medulla of old mice, there were several cavities bounded by a partly ciliated epithelium and containing lymphocytes. The epithelial cells lining the cavities showed intense immunofluorescence for FTS. In addition to the epithelial cells, a certain population of round cells with thin cytoplasm lacking in discernible processes immunofluoresced for FTS. Located both in the medulla and in the cortex, these round cells were postulated to be thymocytes, the target cells of FTS, binding FTS on their cell surface.

Aging↗

[Marginal periodontitis and the immune system. III. Differences in peripheral blood lymphocyte subsets before and after treatment in adult periodontitis patients].

The lymphocyte subsets in the peripheral blood of 8 individuals, aged 25 to 57 yr, with moderate to advanced adult periodontitis were analyzed before and after treatment by means of flow cytometry, and then compared with the findings in 20 normal adults (aged 30 to 45 yr). The results were as follows: the percentage of OKT-8+ (CD 8) in the patients (20.25 +/- 7.15%) was lower than that in normal individuals (31.50 +/- 6.03%, P less than 0.01) while the OKT-4/OKT-8 ratio (2.34 +/- 1.18) was higher than the corresponding ratio in the controls (1.23 +/- 0.37); however, there was no significant difference in the percentages of OKT-3+ (CD 3), OKT-4+ (CD 4) and Leu-12+ (CD 19) between patients and normal subjects. The percentages of OKT-3+, OKT-4+, OKT-8+, Leu-12+ and OKT-4/OKT-8 after the periodontal therapy did not show a significant difference compared with the data obtained before treatment. These results indicate that the decrease in suppressor/cytotoxic T-cell population may be a kind of pathological disposition of the initiation and/or course of adult periodontitis.

Adult↗

[Hepato-portal-splenic dynamics after hepatectomies].

The present study was performed to clarify the regeneration and splenic changes following hepatectomy. The processes were compared between the three classes (L greater than 50%, 30 less than M less than 50%, S less than 30%) categorized by the resection rate (%) calculated by CT scan in the 26 cirrhotics (LC) and 22 non-cirrhotics (N). Hepato-splenic volumes were serially measured by CT scan. The regenerative speed (cm3/day) of the remaining liver were significantly higher in the N group than LC and in the larger resection class. Liver functions tended to return to the initial levels behind the time of restoration of the liver volumes. The delay was partially caused by the posttransfusion hepatitis (PTH), which developed more frequently with an increase of fresh frozen plasma transfusion given. The changing pattern of splenic size was strongly regulated by the massiveness of hepatectomy. Newly developed posthepatectomy esophageal variceal ruptures were endoscopically determined in the 10% of the 129 late deaths after hepatectomies for hepatomas (1973-1987) with or without recurrences and its occurrence was found to be enhanced in the massive resection in the LC group ended with the poor regeneration of the liver and persistent postoperative splenic enlargement.

Esophageal and Gastric Varices↗