PubMed Health⌕ Search

Biomedical subjects

T Mitamura

Publications and source records attributed to T Mitamura.

At least 55 records · Page 3Linked to original sources
PubMed1989

Enzymatic properties of isozymes and variants of glucose dehydrogenase from Bacillus megaterium.

Three glucose dehydrogenases (GlcDH) from Bacillus megaterium, GlcDH-I, GlcDH-II and GlcDH-IWG3, were purified from Escherichia coli cells harboring one of the hybrid plasmids, pGDK1, pGDK2 and pGDA3, respectively, pGDK1 and pGDK2 contain two isozyme genes, gdhI and gdhII, respectively, from B. megaterium IAM 1030 and pGDA3 contains an isozyme gene from B. megaterium IWG3; GlcDH-IWG3 is a variant of GlcDH-I. GlcDH-I and GlcDH-II have similar pH/activity profiles and the profile for GlcDH-IWG3 is identical to that of GlcDH-I. The pH/stability profiles of these enzymes show that GlcDH-IWG3 is the most stable enzyme in the acidic region, while GlcDH-II is the most stable in the alkaline region, and GlcDH-I is the most unstable throughout the entire pH range examined. As for thermostability, GlcDH-II is the most resistant against heat inactivation at pH 6.5. The values of the first-order rate constant for heat inactivation at 50 degrees C are 0.27 min-1, 0.05 min-1 and 0.11 min-1 for GlcDH-I, GlcDH-II and GlcDH-IWG3, respectively. Kinetic studies show that these enzymes have similar kinetic constant values except that there are some differences in Kia for NAD(P) and Ka (the limiting Michaelis constant) for NAD; the values of the ratio of Kia for NAD and NADP are 11,340 and 8.7 for GlcDH-I, GlcDH-II and GlcDH-IWG3, respectively. GlcDH-I and GlcDH-IWG3 have very similar substrate specificities and GlcDH-II has a slightly higher specificity for D-glucose and 2-deoxy-D-glucose than the others. The results are discussed on the basis of the amino acid substitutions between the enzymes.

Bacillus megaterium↗
PubMed1989

Determination of the active-site serine of 6-aminohexanoate-dimer hydrolase.

Diisopropylfluorophosphate, an inhibitor of serine proteinase, was used to label 6-aminohexanoate-dimer hydrolase, a nylon oligomer degradative enzyme of Flavobacterium sp. K172. More than 95% of the enzyme activity was lost upon incorporation of 1-1.5 molecules inhibitor/subunit of the enzyme. The tryptic peptide of the labeled enzyme was purified by HPLC (reverse-phase partition) and its amino acid sequence was identified. Radioactivity was found to be incorporated into an 8-amino-acid peptide (108His-Leu-Leu-Met-Ser-Val-Ser-Lys115). Amino acid alteration from Ser to Ala at the position 112 by site-directed mutagenesis caused loss of enzyme activity to below the detection threshold (1% of the activity of the parental enzyme). These results indicate that Ser112 is essential for the activity.

Affinity Labels↗
PubMed1989

[The influence of green tea upon the improvement of iron deficiency anemia with pregnancy treated by sodium ferrous citrate].

Green tea is indispensable to our everyday life. In Japan it has long been common knowledge that the ingestion of green tea should be avoided before and after the intake of iron preparations. There have recently been some reports, however, that deny the effect of green tea on iron preparations. A study was conducted on pregnant patients with anemia, using sodium ferrous citrate (Ferromia). The drug was administered to a group of patients taking green tea and a group taking water. Our results can be summarized as follows. 1. Hemoglobin, serum iron and total iron binding capacity were markedly improved after the administration of the iron preparation, and there was no difference between these parameters in the two groups of patients. 2. There was a tendency for patients with hypochromia to show a more marked improvement in hemoglobin in both groups. 3. Anemia cured in 96.7% of patients in the green tea group and in 93.4% of patients in the water group after the oral administration of the iron preparation. 4. The incidence of side effects stood at 18.3% for the green tea group and 21.9% for the water group, there being no significant difference. No serious side effects were elicited in the present study.

Adult↗
PubMed1988

Lipoprotein cholesterol concentrations in patients with Behçet's disease.

Serum cholesterol concentrations among very low, low, and high density lipoproteins (VLDL, LDL and HDL) in 12 male patients with Behçet's disease were compared with those of 12 normal male subjects. Serum lipoproteins were separated by a combination of ultracentrifugation and gel filtration chromatography. The patients had significantly (p less than 0.001) lower concentrations of HDL-cholesterol than the control subjects (356 +/- 62 mg/l vs. 573 +/- 108 mg/l, means +/- SD). The cholesterol concentrations in apolipoprotein B-containing lipoproteins (VLDL and LDL) from the patients tended to be reciprocally higher than those of the controls, though not statistically significant. There was no difference in serum total cholesterol concentrations. The chemical composition of HDL from the patient group was characterized by higher protein and lower cholesterol (both esterified and free) contents compared with the control HDL.

Adult↗
PubMed1988

2-dimensional flow cytometric analysis of peripheral blood T lymphocytes from patients with systemic lupus erythematosus: preferential expression of HLA-DR antigen on the surface of Leu 2a+ cells.

2-dimensional flow cytometric analysis of the peripheral blood T lymphocytes from 20 patients with systemic lupus erythematosus showed a significant increase in the percentage of Leu 2a+ 15- cytotoxic subset irrespective of disease activity compared to 35 age and sex matched healthy individuals. The percentage of Leu 2a+ HLA-DR + cells also increased significantly in both patients with active and inactive disease compared to the controls. In contrast, both the relative and absolute number of Leu 3a+ 8+ cell (suppressor/inducer T cell) showed a significant reduction in active and inactive disease if compared to controls. All of these changes were more drastic in the patients with active disease.

Adult↗
PubMed1987

Glucocorticoid-induced elevation of serum high-density lipoprotein-cholesterol and its reversal by adrenocorticotropin in the rat.

The effect of administration of a high dose of glucocorticoid (triamcinolone) on serum lipids and lipoproteins was studied in rats. Changes in serum lipids, especially cholesterol, were most marked when 5 mg/kg body weight of triamcinolone was injected daily for 5 days. Serum lipoproteins were separated by ultracentrifugation followed by gel-filtration chromatography. Cholesterol distribution between apolipoprotein B-containing lipoproteins (very-low-density and low-density lipoproteins), high-density lipoprotein1 (HDL1), and HDL2 was determined after administration of triamcinolone with or without additional treatment with adrenocorticotropin (ACTH; Cortrosyn, 6 IU/rat). When triamcinolone was administered, cholesterol concentrations in HDL1 and HDL2 were elevated in a dose-dependent manner, but there was no significant change in apolipoprotein B-containing lipoprotein cholesterol levels. When ACTH was administered in combination with triamcinolone, the concentrations of all serum lipids except triacylglycerol were significantly lowered compared with rats treated with triamcinolone alone. HDL1-cholesterol concentration in serum was significantly (P less than 0.001) lowered from 69 +/- 13 mg/dl (mean +/- S.D.) in triamcinolone-treated rats to 36 +/- 4 mg/dl by the administration of ACTH plus triamcinolone. The additional administration of ACTH in triamcinolone-treated rats caused a slight, but significant, decrease in cholesterol concentration in apolipoprotein B-containing lipoproteins; however, HDL2-cholesterol level was not significantly affected, although there was a tendency for it to be lowered.

Adrenocorticotropic Hormone↗
PubMed1987

Clinical evaluation of three types of plasmapheresis in a patient with type IIa familial hypercholesterolemia.

Long-term plasmapheresis (PP) therapy was studied in a 56-year-old patient with homozygous type IIa familial hypercholesterolemia also suffering from severe coronary heart disease. Three different PP techniques, plasma exchange (PE), double-membrane-filtration plasmapheresis (DFP), and the recently developed low-density lipoprotein adsorbent column (adsorption plasmapheresis, adsorption PP), were used in an attempt to develop better means of managing the disease. All three techniques showed similar elimination efficiency with respect to plasma total cholesterol level. Adsorption PP with minimal supplemental plasma protein managed the circulatory status of the patient better than DFP during extracorporeal treatment. In the course of PP therapy xanthoma tuberosum markedly regressed, and the cardiac status of the patient was clearly improved.

Angiography↗
PubMed1987

Detection of immune complexes in systemic lupus erythematosus with the C1q solid phase assay: correlation with nDNA antibodies and hypocomplementemia.

Three immune complex assays, the monoclonal rheumatoid factor inhibition (mRF), the C1q solid phase (C1q-SP), and the C1q fluid phase binding (C1q-BA) assays, were compared with native DNA antibody (nDNA Ab) titers and serum hemolytic complement (CH50) levels in serial analyses of patients with systemic lupus erythematosus (SLE). No correlation was evident among the immune complex assays. A positive correlation was observed between the C1q-SP and nDNA Ab assays, and a negative correlation was observed between the C1q-SP and CH50 assays. Evidence is presented that these correlations are related to the presence of complement-fixing nDNA Ab. The C1q-SP may be useful in delineating the basis for the unexplained association of nDNA Ab and hypocomplementemia.

Antigen-Antibody Complex↗
PubMed1986

Enhanced endothelial cell proliferation in acute Kawasaki disease (muco-cutaneous lymph node syndrome).

Paired sera from 30 patients with muco-cutaneous lymph node syndrome (Kawasaki disease) were studied for possible effects on human vascular endothelial cells growth in vitro. The majority of sera from acute phase muco-cutaneous lymph node syndrome patients significantly enhanced endothelial cell proliferation more than those from convalescent phase patients, infectious diseases patients, and age-matched normal controls. This stimulation was considered to be specific for EC since muco-cutaneous lymph node syndrome sera did not enhance fibroblast growth more than normal sera. Fractionation of the serum with gel filtration failed to clearly detect the molecular properties of this effect, although both heavy and light material possessed this activity. Extensive search for circulating immune complex in muco-cutaneous lymph node syndrome sera were negative, suggesting that the enhanced endothelial cell proliferation was due to serum components other than immune complexes.

Antigen-Antibody Complex↗
PubMed1985

Situs ambiguous with polysplenia complicated by renal adenocarcinoma.

Two men developed renal adenocarcinoma in association with situs ambiguous off with polysplenia (SAP) (also known as the polysplenia syndrome). Features of their diseases included (1) no normal spleen--just splenuli, (2) interruption of the inferior vena cava with azygos or hemiazygos continuation, (3) bilateral hyparterial bronchi, (4) cardiac malformations, (5) renal adenocarcinomas originating from the kidneys, ipsilateral to the anomalous spleens. The association of renal adenocarcinomas and SAP has not been previously reported, to our knowledge. We suggest that renal adenocarcinoma and SAP may share a common pathogenetic link.

Abnormalities, Multiple↗
PubMed1984

Alterations of high density lipoproteins in experimental intrahepatic cholestasis in the rat induced by administration of alpha-naphthylisothiocyanate.

It has previously been reported that abnormally enlarged high density lipoproteins (HDL) appear in rats with extrahepatic cholestasis induced by ligation of the common bile duct. To see whether similar changes in HDL occur in intrahepatic cholestasis in rats, we studied HDL alterations in rats treated with alpha-naphthylisothiocyanate (ANIT), which is known to produce a cholestatic response in rats similar to intrahepatic cholestasis in man. Findings were obtained which indicated changes in HDL similar to those in bile duct-ligated rat serum: HDL from ANIT-treated rats were separated into two subfractions, enlarged particles and smaller ones, on Bio-Gel A5m column chromatography. In electron micrographs, the two subfractions appeared spherical and the diameters of the enlarged particles and the other ones were 15.0 +/- 2.6 nm and 11.5 +/- 2.2 nm, respectively. Both subfractions showed slow alpha-mobility in agarose gel electrophoresis. The enlarged HDL had apoE as their major apoprotein, while apoA-I was the major apoprotein in the other HDL subfraction. The enlarged HDL contained less protein and more cholesterol than the other HDL subfraction. The two HDL subfractions were also separated by heparin-Sepharose affinity chromatography.

1-Naphthylisothiocyanate↗
PubMed1984

[A study of morphopathological changes in the ovary caused by parabiotic union in rats].

Male and female Wistar rats from the same brood were joined parabiotically and histopathological changes in the ovary of the reactor were observed from the 8th to the 41st week. Only one tumor, a granulosa cell tumor appearing in the 28th week, was seen to form. Histogenetically, it appeared to have arisen from the follicular granulosa cells. In many cases, stromal luteinization progressed until the entire ovary appeared to consist of luteinized tissue, but in no case were tumor features noted. Changes followed the same process as in autotransplantation of the ovary into the spleen or as in irradiation; eventual tumor formation was judged likely from the observations in some cases. The cause of the extremely low rate of tumor formation in this experiment is thought to be inhibition of gonadotropin production by estrogen transferred from reactor to partner via capillary communicating branches.

Animals↗