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T Hata

Publications and source records attributed to T Hata.

At least 19 recordsLinked to original sources
PubMed1992

Identification of inducible calmodulin-dependent nitric oxide synthase in the liver of rats.

A calmodulin-dependent nitric oxide synthase was significantly induced in the liver of rats treated intravenously with heat-killed Propionibacterium acnes and 5 days later with Escherichia coli lipopolysaccharide. The apparent calmodulin-dependent and -independent isozymes were separated by Mono Q column chromatography after their partial purification by 2',5'-ADP-agarose affinity chromatography. Both enzymes had a molecular weight of 125,000 as determined by SDS-polyacrylamide gel electrophoresis and required NADPH, tetrahydrobiopterin, and dithiothreitol as cofactors. Their activities were completely inhibited by the specific nitric oxide synthase inhibitors NG-monomethyl-L-arginine and N omega-nitro-L-arginine at 80 and 800 microM, respectively. The peptide maps of these two isozymes with lysylendopeptidase and their reverse-phase column chromatographic profiles were indistinguishable. In the presence of bovine calmodulin, the purified calmodulin-dependent isozyme behaved as a calmodulin-independent isozyme on Mono Q column chromatography. The purified calmodulin-independent isozyme was converted to a calmodulin-dependent isozyme by EDTA and EGTA. Calmodulin blot analysis using 125I-calmodulin showed that the two isozymes bound calmodulin equally efficiently.

Amino Acid Oxidoreductases↗
PubMed1992

Molecular design of a eukaryotic messenger RNA and its chemical synthesis.

A designed mRNA consisting of 42 ribonucleotides having the cap structure was synthesized. The capped leader sequence of the brome mosaic virus (BMV) mRNA 4, m7G5'pppGUAUUAAUA (F-1), was synthesized by the phosphotriester method and followed by the capping reaction. A 32-mer consisting of an initiation codon (AUG), the coding region corresponding to a bacterial pheromone cAD1 and two stop codons, was constructed by the 18-mer (F-2) and 14-mer (F-3), which were synthesized by the phosphoramidite method. 2'-,3'-O-Methoxymethylene-guanosine 5'-phosphate was condensed with F-3 using P1-2',3'-O-methoxymethyleneguanosine-5'-yl P2-adenosine-5'-yl pyrophosphate (9) with T4 RNA ligase. The chemically synthesized RNA fragments were ligated successively with T4 RNa ligase to afford the whole RNA molecule.

Amino Acid Sequence↗
PubMed1992

Platelet hypoaggregability in rats exposed to SART stress (repeated cold stress).

A prolongation of bleeding time accompanied by thrombocytopenia and abnormalities in coagulation-fibrinolysis systems has been observed in laboratory animals exposed to a chronic form of environmental stress induced by severe fluctuations of air temperature, known as SART (specific alternation of rhythm in temperature) stress. In order to clarify the hemostatic profile under SART stress in more detail, the present study examined platelet aggregability in vitro as well as in vivo in stressed rats. During exposure to stress, thrombocytopenia developed from day 5, and remained up to at least day 14. In vitro aggregation of platelets stimulated by ADP or collagen was markedly decreased in stressed rats, compared with unstressed rats. Furthermore, stressed rats exhibited in vivo hypoaggregability of platelets, as estimated by the magnitude of the drop in circulating platelet counts following intravenous injection of ADP and collagen. Protein and cholesterol content in platelets remained constant after stress exposure. These results indicate that SART-stressed rats exhibit platelet dysfunctions in addition to thrombocytopenia. Considering the previous findings, the hemostatic system under SART stress appears to show a general tendency toward hemorrhage.

Adenosine Diphosphate↗
PubMed1992

Conformational rigidity of specific pyrimidine residues in tRNA arises from posttranscriptional modifications that enhance steric interaction between the base and the 2'-hydroxyl group.

In order to elucidate roles of the 2'-O-methylation of pyrimidine nucleotide residues of tRNAs, conformations of 2'-O-methyluridylyl(3'----5')uridine (UmpU), 2'-O-methyluridine 3'-monophosphate (Ump), and 2'-O-methyluridine (Um) in 2H2O solution were analyzed by one- and two-dimensional proton NMR spectroscopy and compared with those of related nucleotides and nucleoside. As for UpU and UmpU, the 2'-O-methylation was found to stabilize the C3'-endo form of the 3'-nucleotidyl unit (Up-/Ump-moiety). This stabilization of the C3'-endo form is primarily due to an intraresidue effect, since the conformation of the 5'-nucleotidyl unit (-pU moiety) was only slightly affected by the 2'-O-methylation of the 3'-nucleotide unit. In fact even for Up and Ump, the 2'-O-methylation significantly stabilizes the C3'-endo form by 0.8 kcal/.mol-1. By contrast, for nucleosides (U and Um), the C3'-endo form is slightly stabilized by 0.1 kcal/.mol-1. Accordingly, the stabilization of the C3'-endo form by the 2'-O-methylation is primarily due to the steric repulsion among the 2-carbonyl group, the 2'-O-methyl group and the 3'-phosphate group in the C2'-endo form. For some tRNA species, 2-thiolation of pyrimidine residues is found in positions where the 2'-O-methylation is found for other tRNA species.(ABSTRACT TRUNCATED AT 250 WORDS)

Dinucleoside Phosphates↗
PubMed1992

Hepatocyte growth factor is a paracrine factor for renal epithelial cells: stimulation of DNA synthesis and NA,K-ATPase activity.

The expressions of mRNAs of hepatocyte growth factor (HGF) and its receptor (c-met) and its effects were examined in cultured renal epithelial cell lines (OK, LLCPK1, and MDCK cells) and rat mesangial cells in primary culture. Northern blot analysis revealed the presence of HGF mRNA in mesangial cells, but not in epithelial cells. c-met mRNA was detected in epithelial cells, but not in mesangial cells. HGF stimulated [3H]-thymidine incorporation (DNA synthesis) dose-dependently in OK and LLCPK1 cells, but not in MDCK and mesangial cells. Ouabaine sensitive rubidium uptake (Na,K-ATPase activity) was stimulated by 63% with HGF (10 ng/ml) treatment for 16hr in MDCK cells. The results suggest that HGF is produced in the kidney, at least in mesangial cells and works on epithelial cells to stimulate the proliferation and/or to modify cell functions in a paracrine manner.

Animals↗
PubMed1992

Mathematical modeling of fetal splenic growth: use of the Rossavik growth model.

Growth of the fetal spleen has been monitored by measurements of the maximal length (SL), profile circumference (SC), and profile area (SA) of the spleen, from 20 weeks to 41 weeks, menstrual age. Growth curves for these parameters have been determined using a specially developed growth curve model [P = c(t)k + s (t)]. R2 values of 94.3%, 94.9%, and 96.3% were obtained for SL, SC, and SA, respectively. Variability analysis indicated some progressive increase in variability with menstrual age for these three parameters. Variability data were used with the growth curve models to determine standard curves for SL, SC, and SA. These standard curves provide a superior means for evaluating the normal splenic growth in the fetus and for identifying splenic abnormalities in utero.

Embryonic and Fetal Development↗
PubMed1992

New pelvic sonoangiography for detection of endometrial carcinoma: a preliminary report.

Pelvic sonoangiography (PSAG) using transvaginal color Doppler was done on 16 postmenopausal patients with abnormal uterine bleeding. Seven women had no endometrial carcinoma and nine had carcinoma. No flow was detected around and within the endometrium in noncancer patients. PSAG showed a feeder artery (blood flow with pulsation that runs into and clings to the tumor) in all patients with endometrial carcinoma, and intratumor blood flow (a mixture of pulsating and constant flow within the tumor) was evident in 7 of 9 patients with endometrial carcinoma. These findings were confirmed by conventional pelvic angiography. In the diagnostic evaluation of PSAG for endometrial carcinoma, both sensitivity and specificity were 100%. We conclude that PSAG with transvaginal color Doppler can be used to detect endometrial carcinoma in postmenopausal women with abnormal uterine bleeding and that this method might be applicable to selecting patients who really require diagnostic surgery for endometrial cancer.

Aged↗
PubMed1992

Ovarian tumors of low malignant potential: transvaginal Doppler ultrasound features.

Twenty-nine patients with ovarian tumors were studied with transvaginal Doppler ultrasound before surgery. After surgery, pathological examination revealed that 26 tumors were benign and 3 were of low malignant potential (LMP). B-mode sonography, computed tomography, and magnetic resonance imaging showed no positive findings for malignancy in these 3 cases of LMP. Serum levels of the CA-125, tissue polypeptide antigen, and carcinoembryonic antigen were also within the normal range. Blood flow velocity waveforms were evaluated by the calculation of the resistance index (RI). There was a significant difference between the RI value (0.818 +/- 0.223) in benign tumors and that (0.418 +/- 0.072) in LMP (P less than 0.01). When the 0.56 (mean of LMP tumor RI value + 2SD) was considered as the cutoff value of RI, the sensitivity was 100% and the specificity was 88.5%. Transvaginal Doppler ultrasound provides a useful diagnostic information for the differentiation of benign and LMP ovarian tumors before surgery.

Adult↗
PubMed1992

Sarcolemmal Na(+)-K(+)-ATPase activity in congestive heart failure due to myocardial infarction.

Because the Na+ pump is considered to modulate the contractile force development by the cardiac muscle and depressed cardiac pump function is the hallmark of congestive heart failure, we characterized the sarcolemmal Na(+)-K(+)-ATPase activity in failing rat hearts after myocardial infarction. For this purpose, the left ventricular coronary artery was ligated, and hearts were examined 4, 8, and 16 wk later; sham-operated animals served as controls. Hemodynamic assessment revealed the presence of abnormal cardiac function at 4, 8, and 16 wk. Although accumulation of ascites in the abdominal cavity was present in experimental animals at 4 wk, other clinical signs of congestive heart failure in experimental rats including lung congestion and cardiac dilatation were evident 8 and 16 wk after induction of myocardial infarction. The depression in Na(+)-K(+)-ATPase activity in purified sarcolemmal membrane from the uninfarcted experimental left ventricle at 8 wk was associated with depressed Vmax without any changes in the affinities for Mg-ATP, Na+, and K+ or the pH optimum for the enzyme. The Kd values of both the high- and low-affinity binding sites for [3H]ouabain, which is believed to interact with Na(+)-K(+)-ATPase, were increased; however, no change in the density of either class of ouabain binding site was evident. The depression of Na(+)-K(+)-ATPase activity in failing hearts at 16 wk of myocardial infarction was not different from that observed at 8 wk but the enzyme activity was not altered at 4 wk of coronary occlusion. These data support the view that depression of Na(+)-K(+)-ATPase activity may serve as an adaptive mechanism during the development of congestive heart failure.

Alamethicin↗
PubMed1992

Sarcolemmal calcium transport in congestive heart failure due to myocardial infarction in rats.

Because Na(+)-Ca2+ exchange and Ca2+ pump are thought to play a role in sarcolemmal Ca2+ movements, we examined the Na(+)-dependent Ca(2+)-uptake and ATP-dependent Ca(2+)-uptake activities in failing heart after myocardial infarction in rats. The left coronary artery was ligated, and the viable left ventricle was used 4, 8, and 16 wk later; sham-operated animals served as controls. Increased left ventricular diastolic pressure and decreased positive and negative change in pressure over time were observed in experimental animals at 4, 8, and 16 wk; these changes were associated with accumulation of fluid in the abdominal cavity. The sarcolemmal Na(+)-dependent Ca2+ uptake was depressed in 4-, 8-, and 16-wk experimental hearts. The decrease in sarcolemmal Na(+)-dependent Ca2+ uptake in failing hearts was seen when the activity was assayed either as a function of time or Ca2+ concentration; a depression of maximal velocity without any change in activity constant for Ca2+ was observed. No alteration in the Ca2+ pump (ATP-dependent Ca2+ accumulation and Ca(2+)-stimulated adenosinetriphosphatase) activities was evident in the 4-, 8-, and 16-wk experimental groups. These data suggest that changes in the Na(+)-dependent Ca2+ handling by the sarcolemmal membrane may be associated with contractile abnormalities in this model of congestive heart failure.

Adenosine Triphosphate↗
PubMed1992

Coexistence of the Ekbom syndrome and lilliputian hallucination.

A patient who showed Ekbom's syndrome, i.e. delusions of parasitosis, and also lilliputian hallucination is described. She was diagnosed as senile dementia based on the diagnostic criteria of DSM-III-R and cerebral imaging techniques. When she was 74 years, she felt a mowworm-like wriggle in her stomach and their travels all over her body. When she was 78 years, she saw dressed-up dwarfs dance or march on her abdomen. Since the case showed simultaneously delusions of parasitosis and lilliputian hallucinations, it cannot be denied that she has undetected lesions in the brainstem. In this case, the delusions and hallucinations seem to have occurred as a part of psychopathological signs of senile dementia.

Aged↗
PubMed1992

Fetal atrial measurements before and after delivery: correlation with plasma atrial natriuretic peptide.

Fetal and early neonatal atrial measurements correlating with plasma atrial natriuretic peptide were studied to evaluate the circulatory change before and after delivery in a longitudinal study of 10 normal fetuses from 1 week before until 5 days after delivery. Before delivery, right atrial area value was significantly larger than that of left atrial area; however, there were no significant differences between left and right atrial areas after delivery. Right atrial area value before delivery was significantly larger than those after delivery, whereas the left atrial area did not change before and after delivery. Combined atrial area value before delivery was also larger than those after delivery. Plasma atrial natriuretic peptide values did not change after delivery. These results suggest that the change from fetal to neonatal circulation mainly caused by the pulmonary circulation induces the change of right atrial size before and after delivery.

Atrial Natriuretic Factor↗
PubMed1992

Effects of (+)-, (-)- and (+/-)-indenestrols A and B on microtubule polymerization.

Indenestrol A (IA) is a metabolite of diethylstilbestrol (DES), and indenestrol B (IB) is an analog of IA. IA was simply obtained from E,E-dienestrol in the presence of dilute sulfuric acid, and a mixture of IA and IB was formed by thermal cyclization of E,E-dienestrol. In order to elucidate the effects of optically active IA and IB on microtubule assembly, the IA and IB enantiomers were separated to greater than 99% purity by high-pressure liquid chromatography using a chiral column. The di(4-bromobenzoate) of (-)-IB was analyzed by X-ray crystallography and its absolute structure was determined as C(3)-S. The (+)-, (-)-, and (+/-)-indenestrols A and B were shown to be inhibitors of microtubule assembly in vitro using microtubule proteins from porcine brain. (+/-)-IB is more active than (+/-)-IA, and the order of inhibitory activity of the enantiomers on microtubule assembly was (+)-IB greater than (+)-IA greater than (-)-IA greater than (-)-IB.

Animals↗
PubMed1992

[Effects of Kamikihi-To on autonomic imbalances in SART-stressed (repeated cold-stressed) mice].

The effects of Kamikihi-To (KMK), a traditional Chinese medicine, on autonomic imbalances were evaluated in SART-stressed (repeated cold-stressed) mice. These animals exhibited decreases in pain threshold and contraction of duodenum by acetylcholine, and they showed changes in their electrocardiogram and hematological parameters. All symptoms are thought to be caused by dysautonomia. KMK in dosages of 0.5 and 1.0 g/kg were administered to mice once a day for 8 consecutive days. SART stress was induced from the second day. KMK prevented the decrease in the pain threshold and contraction of the duodenum, although it had no effect on the electrocardiographic or hematological changes. KMK had no similar effect on unstressed mice. This data suggests that KMK might be useful for the treatment of clinical autonomic imbalances.

Acetylcholine↗
PubMed1992

Regulatory effect of neurotropin on nasal mucosal hypersensitivity in guinea pigs caused by SART (intermittent exposure to cold) stress.

We stated that SART-stressed guinea pigs showing nasal mucosal hypersensitivity would serve as an animal model for the in vivo evaluation of antiallergic drugs. In the present study, the mode of action of Neurotropin on nasal allergy compared with those of antiallergic drugs was studied by using SART-stressed guinea pigs. Daily administrations of Neurotropin improved the methacholine-induced hypersecretion and histamine-evoked sneeze response, which are parameters of nasal mucosal hypersensitivity, and increased the density of muscarinic ACh receptors located on the nasal mucosa caused by SART stress. In addition, the inhibitory action on nasal secretion in a passively sensitized model was more intense in SART-stressed guinea pigs than in normal ones. Ketotifen and tranilast were also found to have marked effects on nasal secretion in the passively sensitized SART-stressed model, but only had weak effects on nasal mucosal hypersensitivity. Neurotropin significantly potentiated the action of ketotifen or tranilast. Thus, at least part of the inhibitory effect of Neurotropin on nasal symptoms such as watery secretion and sneezing is thought to have been brought forth through the regulatory action on nasal mucosal hypersensitivity, and its combined use with antiallergic drugs would be a very effective therapeutic regimen for nasal allergy.

Analgesics↗