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S Maekawa

Publications and source records attributed to S Maekawa.

At least 19 recordsLinked to original sources
PubMed1992

A novel 24-kDa microtubule-associated protein purified from sea urchin eggs.

Chromatographic fractionation of a crude extract of sea urchin eggs on a hydrophobic column enabled us to find a new 24-kDa microtubule-associated protein (SU-MAP24) that bound tightly to the column and was eluted under alkaline conditions. Biochemical studies using the purified protein showed its direct binding to microtubules reconstituted from tubulin purified from starfish sperm outer fibers. SU-MAP24 promoted tubulin polymerization in a dose-dependent manner. Immunoblotting analysis showed that SU-MAP24 is present in a microtubule protein fraction obtained from a crude extract using taxol, and immunostaining of paraffin-sectioned metaphase eggs showed its localization in the mitotic apparatus. These results show that SU-MAP24 is a newly identified microtubule-associated protein.

Alkaloids↗
PubMed1992

Proposal of a new scheme for the serological typing of Enterococcus faecalis strains.

No systematic study on serotyping of Enterococcus faecalis has been reported since 1964 when M.E. Sharpe conducted serotyping of group D streptococcus in U.K. So, we attempted to re-evaluate serotyping of E. faecalis. For this purpose, we received 42 Sharpe's strains and first examined for their biochemical characteristics as E. faecalis. Only 9 of the 42 strains were identified as E. faecalis. We raised rabbit antisera against a large number of E. faecalis strains, including the 9 Sharpe's strains, 2 strains obtained from CDC in U.S.A. and 36 strains isolated from patients hospitalized in different cities of Japan. From the results of cross-agglutination tests and absorption tests performed on these antisera using a large number of E. faecalis strains, we were able to classify 21 distinct serotype strains and to prepare 21 monospecific typing antisera by absorption of the antisera to the type strains with appropriate cross-agglutinating strains. When 832 E. faecalis strains were serotyped with the 21 typing antisera, 638 strains (76.7%) were typable. Thus, we propose a provisional scheme of 21 distinct serovars in E. faecalis.

Agglutination Tests↗
PubMed1992

Beta(+)-thalassemia with hemochromatosis.

A 64-year-old man was admitted due to ascites. Laboratory data showed hemoglobin 6.7 g/dl, mean corpuscular volume 82 fl, and ferritin 2,360 ng/ml. Liver biopsy showed hemochromatosis. The diagnosis of beta-thalassemia was suggested by a decreased ratio of beta/alpha-globin synthesis in vitro (0.26). Cloning of the beta-globin gene showed A-to-G mutation in the first base of the ATA box. He was confirmed to be homozygous for this specific allele by beta-gene complex analysis and analysis of Southern blot hybridization of the alpha- and beta-globin genes. His two sons were confirmed to be heterozygous for this allele.

Adult↗
PubMed1992

[A case of rheumatoid arthritis associated with progressive systemic sclerosis and primary biliary cirrhosis in the presence of various autoantibodies].

The patient (a 49 year-old, female) had been diagnosed in Apr. 1987 as having rheumatoid arthritis (RA) following the history as chronic non-A, non-B hepatitis for 4 years. Progressive systemic sclerosis (PSS) and primary biliary cirrhosis (PBC) were also defined on 1989 in the same patient mainly due to proximal scleroderma and histological findings of liver biopsy. On the other hand, the coexistence of rheumatoid factor, anti-Scl-70 antibody, anti-mitochondrial antibody (anti-MC, anti-MD and an unidentified fraction) and anti-centromere antibody have been observed with marked polyclonal hypergammopathy in her sera since July 1990. Her disease activity has been controlled well with the administration of D-penicillamine and ursodeoxycholic acid during recent clinical course. Few cases of RA associated with PSS and PBC, showing various autoantibodies as a disease marker in sera, have been reported. In order to evaluate the mechanisms of autoimmune disease especially chain reaction of autoimmunity, it should be important to accumulate the reports concerning such cases.

Arthritis, Rheumatoid↗
PubMed1992

Purification of a membraneous actin binding protein from bovine adrenal medulla.

An actin binding protein having a molecular mass of 39,000 was purified from the Triton extract of bovine adrenal medulla membrane fraction using DNase I affinity column and following chromatographies. Specific antibody was produced against the protein and immunoblotting analysis of tissue extract showed the purified protein was not a breakdown product of a larger protein and also showed the presence of this protein in bovine adrenal medullary chromaffin cells and rat pheochromocytoma cells (PC12). An immunoblotting analysis of membrane fractions treated with nucleotides and their analogues showed that this protein was specifically solubilized in the presence of GTP gamma-S.

Actins↗
PubMed1991

Two Ca2(+)-binding proteins in the mitotic apparatus of sea urchin eggs.

Two Ca2(+)-binding proteins of sea urchin eggs were purified and partially characterized. They showed Ca2(+)-dependent binding to actin filaments and Ca2(+)-dependent changes of fluorescence intensity which was used to estimate the affinity constant of these proteins to Ca2+ ions. Ca2+ ions did not increase phospholipid binding ability of these proteins. Therefore these proteins are distinguished from the calpactin family. Staining of sections of metaphase eggs embedded in paraffin showed their localization in the mitotic apparatus. Furthermore, staining of whole mount eggs with anti-tubulin and antibodies against these proteins, followed by observations with confocal laser-scanning microscopy showed their co-localization with microtubules more clearly. In vitro co-sedimentation assay of microtubules with these proteins, however, showed no interaction between them. This suggested that some structures surrounding the mitotic apparatus microtubules are responsible for their localization.

Actin Cytoskeleton↗
PubMed1990

1 Alpha-hydroxyvitamin D3 suppresses colonic tumorigenesis induced by repetitive intrarectal injection of N-methyl-N-nitrosourea in rats.

The effect of 1 alpha-hydroxyvitamin D3 (1 alpha (OH)D3) on colonic tumorigenesis induced by chronic treatment with N-methyl-N-nitrosourea (MNU) was studied in rats. Seventy-four female F344 rats received an intrarectal injection of 1 mg of MNU once a week for 40 weeks. Two-thirds of rats were given concomitant administration of 0.2 ml of medium chain triglyceride (MCT) or MCT containing 0.04 microgram of 1 alpha (OH)D3 through an intragastric route thrice weekly. Numbers of rats bearing colonic tumor were 21 in MNU alone (n = 24), 17 in MNU + MCT (n = 25) and 12 in MNU + 1 alpha (OH)D3 group (n = 25) (uncorrected chi 2 = 8.72). The result indicated that colonic tumorigenesis induced by the chronic treatment with MNU was suppressed by oral supplementation of 1 alpha (OH)D3 and the inhibitory effect of 1 alpha (OH)D3 was partly due to the effect of MCT.

Adenoma↗
PubMed1990

Inhibition of actin regulatory activity of the 74-kDa protein from bovine adrenal medulla (adseverin) by some phospholipids.

A 74-kDa protein (adseverin) derived from adrenal medulla severs actin filaments and nucleates actin polymerization in a Ca2(+)-dependent manner but does not form an EGTA-resistant complex with actin monomers, which is different from the gelsolin-actin interaction. The dissociation of gelsolin-actin complexes by phosphatidylinositol 4,5-bisphosphate (PIP2) and the inhibitory effect on actin filament severing by gelsolin was recently reported. This study shows that the activity of adseverin is inhibited not only by PIP2 but also by some common phospholipids including phosphatidylinositol (PI) and phosphatidylserine (PS). Other phospholipids such as phosphatidylcholine (PC) and phosphatidylethanolamine (PE) showed no effect. The addition of PC or PE to PI diminished the inhibitory effect of PI. Triton X-100 and neomycin were also found effective in suppressing the effect of PI, suggesting that the arrangement of polar head groups is important in exerting the inhibitory effect. Ca2(+)-dependent binding of adseverin to PS liposomes but not to PC or PE liposomes was observed by a centrifugation assay.

Actins↗
PubMed1990

Safety of EEA staplers for anastomosis between upper esophagus and the gastric tube.

The EEA stapling devices used for intrathoracic anastomosis between the upper esophagus and the gastric tube in patients with carcinoma of the thoracic esophagus were evaluated, and the results were compared with those of an antesternally reconstructed esophagus. These approaches were both used by the same surgical team. An intrathoracic anastomosis using the EEA stapler was made in 53 patients with carcinoma of the thoracic esophagus. Minor anastomotic leakage occurred in five patients (9.4%). Good results were obtained with total parenteral nutrition for 2 weeks. Intrathoracic anastomotic complications were never fatal. Among another 106 patients with antesternally reconstructed esophagus, with the EEA stapler there were 28 patients with anastomotic leakage (26.4%) and two operative mortalities (1.9%). Intrathoracic anastomosis with the EEA stapler is recommended because it is secure and the operative procedure is simple and time-saving. For successful use of the instrument, proper technical procedures must be followed.

Adult↗
PubMed1990

Effects of 1 alpha-hydroxyvitamin D3 on N-methyl-N-nitrosourea-induced colonic tumorigenesis, and on fecal bile acid profiles with respect to soluble and precipitated phases in rats.

Vitamin D3 inhibited the promotion by exogenous promoters in experimental colonic tumorigenesis. To give more insight into this phenomenon, the effect of 1 alpha-hydroxyvitamin D3 (1 alpha(OH)D3) on N-methyl-N-nitrosourea (MNU)-induced colonic tumorigenesis was studied in rats without exogenous promoters. Fecal bile acids were analyzed to examine as to whether 1 alpha(OH)D3 increased the concentration of soluble bile acids. Eighty-seven female F344 rats received 2 mg of MNU intrarectally 5 times in 2 weeks, and were divided into 3 groups. One group (n = 29) was left without any treatment. Two groups (each, n = 29) were given 0.2 ml of medium chain triglyceride (MCT) or MCT containing 0.04 microgram of 1 alpha(OH)D3 through an intragastric route thrice weekly for 38 weeks. At autopsy, numbers of rats with colonic tumor were 9 (31%), 10 (34%) and 10 (34%) in the group receiving MNU alone, MNU + MCT and MNU + 1 alpha(OH)D3, respectively (chi 2 = 0.103, P less than 0.95). Fecal bile acid profiles showed no appreciable difference among these groups, nor was observed any increase of soluble bile acids in the MNU + 1 alpha(OH)D3 group. These results indicated that the administration of 1 alpha(OH)D3 did not affect colonic tumorigenesis under the condition where exogenous promoters were not applied, and that 1 alpha(OH)D3 did not seem to interfere the formation of bile acid calcium salts in animals on a regular diet.

Animals↗
PubMed1990

[A case report of advanced gastric cancer remarkably responding to mitomycin C, aclacinomycin A, SF-SP and lentinan combination therapy].

A 63-year-old female diagnosed as inoperable gastric cancer was treated with combination immunochemotherapy of Mitomycin C, Aclacinomycin A, SF-SP and Lentinan. In this case, the tumor directly invaded the pancreas and the peritoneal dissemination, metastasis to the para-aortic lymph nodes and Virchow's metastasis were identified. As the result of this therapy, the primary tumor was remarkably reduced in size. The subjective symptoms and the metastasis of the para-aortic lymph nodes and Virchow's metastasis disappeared. The side effect was only mild thrombocytopenia.

Aclarubicin↗
PubMed1990

Preferential binding of cisplatin to mitochondrial DNA and suppression of ATP generation in human malignant melanoma cells.

Effects of cisplatin on mitochondria in human malignant melanoma from gingiva were investigated. Cisplatin bound about 50 times more to mitochondrial DNA than to chromosomal DNA. NADH-ubiquinone reductase was decreased 48 h after the administration to about 40% of the initial level, and cellular ATP level was also depressed at that time. A good correlation was observed between the energy status and NADH-ubiquinone reductase activity. These results suggest that the preferential binding of cisplatin to mitochondrial DNA results in the inhibition of NADH-ubiquinone reductase and consequently in the disturbance of ATP generation.

Adenosine Triphosphate↗
PubMed1989

Active transport and metabolic characteristics of polyamines in the rat lens.

Putrescine, spermidine and spermine were transported into the rat lens against a concentration gradient. This process appeared to be energy-dependent and involved a carrier system different from those for amino acids. Competition experiments suggested that the three polyamines were transported by the same system or very similar systems. Incorporated spermine was converted to spermidine and putrescine, and spermidine was converted to putrescine. In contrast, the conversion of putrescine to spermidine and spermine, or the conversion of spermidine to spermine was not observed. Furthermore, ornithine was not utilized for the synthesis of putrescine. These metabolic characteristics of the polyamines in the rat lens were correlated with the extremely low activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase. Other enzymes of polyamine metabolisms, however, were relatively active. In conclusion, the lens has a very low ability for the de novo synthesis of polyamines. The polyamines in the lens are considered to be supplied form the surrounding intraocular fluid by an active transport system specific for polyamines.

Acetyltransferases↗
PubMed1989

Inhibition by polyamines of methylthiopropylamine-induced ornithine decarboxylase in human lymphoid leukemia Molt 4B cells.

Methylthiopropylamine (MTPA), an inhibitor of spermidine synthase, markedly induced ornithine decarboxylase (ODC) activity (about 30-fold of the basal level) in human lymphoid leukemia Molt 4B cells. This induction was blocked by the addition of spermidine, spermine or putrescine simultaneously with MTPA. Inhibition by spermidine or spermine of the MTPA-induced ODC activity was larger than that by putrescine. The increase of ODC activity by MTPA led to the large increase of cellular putrescine content. This increase of putrescine content was abolished drastically by the simultaneous addition of spermidine or spermine. The increase of ODC activity was almost completely blocked by the addition of cycloheximide or actinomycin D. This finding suggested that the increase of ODC activity was not due to activation of ODC preformed in Molt 4B cells. The ODC induction by MTPA was dose-dependently blocked by adding the calcium channel blockers (verapamil and nifedipine) or protein kinase C inhibitors (1-(5-isoquinolinesulfonyl)-2-methylpiperazine and palmitoyl carnithine). These results suggested that calcium and protein kinase C (PKC) were involved in MTPA-associated induction of ODC.

Cell Line↗