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Biomedical subjects

S Hara

Publications and source records attributed to S Hara.

At least 289 records · Page 16Linked to original sources
PubMed1994

Agarose-carrageenan hybrid polysaccharides from Lomentaria catenata.

Two polysaccharide fractions, PS1 and PS2 from Lomentaria catenata consisted of D-Gal, L-Gal, D-Glc, D-Xyl, D-GlcA and sulphate. Partial hydrolysis led to the isolation and identification of oligosaccharides indicating the co-existence of an agarose and carrageenan backbone structure, in which D-Glc and D-GlcA residues occur as single units branching at O-3 of -->4)alpha-D-Gal(1--> and O-4 of -->3)beta-D-Gal(1-->, respectively.

Carbohydrate Sequence↗
PubMed1994

Crystallization and preliminary crystallographic data of the alpha-amylase inhibitors, Haim I and Paim I.

Two proteins that act as alpha-amylase inhibitors, Haim I and Paim I, were crystallized and preliminary X-ray diffraction studies on them were carried out. We also sequenced Haim I prepared from Streptomyces griseosporeus YM-25 and confirmed that it is composed of 78 amino acid residues. Crystals of Haim I were grown from ammonium sulfate solution mixed with ethanol by the vapor diffusion technique. The crystals grew as hexagonal bipyramids and diffracted X-rays beyond 2.0 A resolution. They belong to the space group P6(1)22 (or P6(5)22) with unit cell dimensions of a = b = 36.7 A, c = 192.4 A, and contain one molecule per asymmetric unit. Paim I, a protein of 39 amino acid residues produced by Streptomyces corchorusii, was crystallized under similar conditions to Haim I. The crystals diffracted X-rays beyond 2.5 A. They belong to the space group P4(1)2(1)2 (or P4(3)2(1)2) with unit cell dimensions of a = b = 65.4 A, c = 96.1 A, and contain three molecules per asymmetric unit.

Amino Acid Sequence↗
PubMed1994

Amino acid sequence of an inhibitor from the silkworm (Bombyx mori) hemolymph against fungal protease.

A novel protein protease inhibitor (FPI-F) which is highly specific for fungal proteases and subtilisin was isolated from the silkworm hemolymph, and its amino acid sequence was determined by conventional methods. The inhibitor consisted of 55 amino acid residues and had a molecular weight of 6,100. The inhibitor included eight cysteine residues and relatively large amounts of acidic amino acids, but neither alanine, methionine nor tryptophan. The amino acid sequence of FPI-F was not homologous with those of other known protease inhibitors of microbe, plant or animal origin.

Amino Acid Sequence↗
PubMed1994

Inhibition of serine proteases of the blood coagulation system by squash family protease inhibitors.

Squash family inhibitors are the smallest protein serine protease inhibitors, being composed of approximately 30 amino acid residues. We isolated 8 squash family inhibitors from the seeds of bitter gourd, squash, gourd and luffa and examined their effect on serine proteases of the blood coagulation system. Five of them prolonged the activated partial thromboplastin time of human plasma to various extents, but three did not. Only Momordica charantia (bitter gourd) trypsin inhibitor-II prolonged the prothrombin time of human plasma. All inhibitors inhibited the amidolytic activities of factor XIIa, plasma kallikrein, factor Xa, but did not inhibit significantly those of factor XIa, factor IXa, factor VIIa, and thrombin. Ki values for factor XIIa, plasma kallikrein, and factor Xa were in the order of 10(-6)-10(-9), 10(-4)-10(-5), and 10(-4)-10(-6)M, respectively. The prolongation of the activated partial thromboplastin time by inhibitors appeared to correspond to their inhibitory potencies for factor XIIa. Momordica charantia trypsin inhibitor-II, which has the strongest inhibitory potency toward the amidolytic activity of factor Xa, with a Ki value 10-100 times smaller than those of other inhibitors, inhibited the activation of factor X by factor VIIa-tissue factor complex or factor IXa, while others did not.

Amino Acid Sequence↗
PubMed1994

Characterization of cytosolic phospholipase A2 in rat mastocytoma RBL-2H3.

We previously reported that cultured mast cells expressed three discrete phospholipases A2 (PLA2S), one of which showed a remarkable preference for phospholipids bearing an arachidonoyl residue at the sn-2 position [M. Murakami, et al., J. Biochem., 111, 175 (1992)]. In the present study, we have purified and characterized this enzyme using rat mastocytoma RBL-2H3 as an enzyme source. The elution profiles of the arachidonoyl-preferential PLA2 activity of rat mastocytoma RBL-2H3 cells on several column chromatographies were indistinguishable from those of 85-kDa cytosolic PLA2 (cPLA2) characterized so far. The molecular mass of the partially purified PLA2 was estimated to be about 90 kDa by gel filtration and it hydrolyzed arachidonate-containing phospholipids preferentially in the presence of submicromolar Ca2+ concentrations. Furthermore, it was immunoprecipitated with an anti-rabbit cPLA2 antibody almost completely. From these observations, we have concluded that the arachidonoyl-preferential PLA2 in mast cells belongs to the "cPLA2" family.

Animals↗
PubMed1994

Morphological analysis of cervical vertebrae in ataxic foals.

Morphological differences between cervical vertebrae were statistically analyzed in ataxic foals to clarify abnormal structural factors in the pathogenesis of this problem. At first, multiple regression analysis and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differences in the growth of all cervical vertebral sites, and the most suitable categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sites in the cervical vertebrae. Twenty-eight ataxic and 19 control foals at the age of 13 months or older were then used for discriminant analysis with 20 variables. As a result, 1-7 variables on C3-C7 were selected for sufficient discrimination, in which the heights of the cranial and caudal orifices of the spinal canal, longitudinal length of the vertebral head and height of the vertebral fossa strongly contributed to the discrimination of all the cervical vertebrae. In addition, the widths and longitudinal diameters of the articular processes on articular surfaces strongly contributed to the discrimination of the caudal region of the neck. In conclusion, it was suggested that the lesion in the cervical spinal cord observed in ataxic foals was caused by morphological abnormalities including osteochondrosis and subsequent degenerative joint disease in the cervical vertebrae.

Animals↗
PubMed1994

Efficacy of the new radiographic measurement method for cervical vertebral instability in wobbling foals.

Cervical myelography and survey radiography was performed on 12 light breed wobbling foals and a new radiographic measurement method was applied for more accurate diagnosis of cervical vertebral instability. Ratios of stenosis of the spinal canal on survey radiography and myelography using relative values in an individual foal were defined on radiograms of lateral flexed position of mid-cervical region, and coincidence between the ratios and histopathological lesions in the cervical spinal cord was investigated. Five of 6 foals had ratios of stenosis on myelography more than 40% at the intervertebral sites where the most severe histopathological lesions were observed. Four of 6 foals had ratios of stenosis on survey radiography more than 40% at the intervertebral sites where the most severe histopathological lesions were observed. Four of 6 foals had ratios of stenosis on survey radiography more than 40% at the intervertebral sites where the most severe histopathological lesions were observed. False-positive diagnosis of CVI was observed in 1 out of 6 foals without histopathological lesion when both ratios of stenosis on myelography and survey radiography were applied. Although the standard value of 40% should be further investigated, the new radiographic measurement method in this study is very useful in clinical diagnosis of cervical vertebral instability in wobbling foals, and the presence of lesions in the cervical spinal cord and their sites by survey radiography may be estimated more accurately.

Animals↗
PubMed1994

[Blalock-Hanlon procedure for mitral atresia with normal aortic valve].

We report two cases of mitral atresia with normal aortic valve. First case was a 16 day-old girl with double outlet right ventricle, and underwent surgical procedure for three times as palliative treatments. The first surgical management involved simultaneous ligation of patent ductus arteriosus and pulmonary artery banding. Then balloon atrioseptostomy (BAS) and Blalock-Taussig shunt were performed after one month of the initial operation, because of severe cyanosis and right pulmonary branch stenosis. Third one was Blalock-Hanlon procedure. Second case was a two month-old boy with pulmonary atresia. Before the admission to our hospital, BAS was performed on this patient. However interatrial communication was not enough, so he underwent Blalock-Hanlon procedure and Blalock-Taussig shunt simultaneously. After these surgical treatments, both patients have done well with minimum interatrial pressure gradient. Early phase surgical maneuver for the atrioseptostomy should have been considered in these two cases.

Aortic Valve↗
PubMed1994

[Bilateral bronchioloalveolar carcinoma, showing familial aggregation of lung cancer].

Bilateral bronchioloalveolar carcinoma in a 56-year-old female is reported. In June 1992, an abnormal shadow was noted on chest X-ray during mass screening. Sputum cytology revealed class V, adenocarcinoma. Mass shadow in both lower lobes were found on chest computed tomography. Simultaneous bilateral thoracotomy was performed by submammary transverse skin incision at the level of the fourth intercostal space. Right lower lobectomy and left S9 partial resection were performed. Bronchioloalveolar carcinoma was confirmed by microscopic findings in both specimens. Four of seven siblings had lung cancer and one had simultaneous renal cell carcinoma. Furthermore, the patient's father, two maternal uncles, one cousin and one nephew also had lung cancer. Two of the brothers and the nephew with lung cancer were confirmed to have well differentiated adenocarcinoma by pathological examination.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1994

[Aortic valve replacement in a patient with chronic idiopathic thrombocytopenic purpura].

We reported a case of aortic valve replacement in a patient with chronic idiopathic thrombocytopenic purpura (ITP). We used high-dose intravenous gammaglobulin therapy (400 mg/kg/day) for five days to increase the platelet prior to the operation. The number of platelet was 8-10 x 10(4)/microliters at admission and it was increased to 23 x 10(4)/microliters before surgery. Aortic valve was replaced to SJM#21A prosthesis using cardiopulmonary bypass. The platelet was transfused after the bypass. Perioperative hemorrhage was moderate and postoperative course was uneventful. We believe that high-dose intravenous gammaglobulin therapy for ITP is effective to minimize perioperative hemorrhage for open heart surgery.

Aged↗
PubMed1994

Antagonism of nitrous oxide antinociception in the rat hot plate test by site-specific mu and epsilon opioid receptor blockade.

The analgesic property of the anesthetic gas N2O has long been known and used to treat pain in clinical medicine and dentistry. The present study was conducted to identify by subtype and possible location the brain opioid receptors that mediate N2O antinociception in rats. A 5-min exposure to 70% N2O consistently evoked an antinociceptive effect in the hot plate test. This drug effect was partly antagonized in dose-related fashion by i.c.v. pretreatment with naltrexone, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 and beta-endorphin, which block multiple, mu and epsilon opioid receptors, respectively. However, the N2O-evoked antinociception was unaffected by i.c.v. pretreatment with either the delta opioid antagonist naltrindole or the kappa opioid antagonist nor-binaltorphimine. When D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 was administered intracerebrally directly into the periaqueductal gray, N2O antinociception was partly antagonized in a dose-dependent manner. The antinociceptive response to N2O was uninfluenced by beta-endorphin administered into the periaqueductal gray. The findings of these pharmacological antagonism studies are consistent with the hypothesis that exposure to N2O causes a neuronal release of beta-endorphin. These results indicate that supraspinal mu and epsilon opioid receptors mediate N2O antinociception in the rat hot plate paradigm and that one central site of such mu but not epsilon opioid receptors is the periaqueductal gray.

Amino Acid Sequence↗
PubMed1993

Crystallographic refinement of Bowman-Birk type protease inhibitor A-II from peanut (Arachis hypogaea) at 2.3 A resolution.

The crystal structure of Bowman-Birk type protease inhibitor A-II from peanut was refined at 2.3 A resolution using a restrained least-squares method. The crystallographic R-factor is 0.196 for 7697 reflections with F > 3 sigma (F) in the range from 6.0 to 2.3 A resolution. Two molecules in an asymmetric unit are independently refined and, their structures are compared with each other. The inhibitor molecule has an elongated shape with two reactive sites, one at both ends of the longest dimension. As a secondary structure, a 4-stranded beta-sheet-like structure is found, in which two water molecules bind two 2-stranded beta-sheets together with six hydrogen bonds. The molecule is constructed by two homologous domains which are related by an intramolecular pseudo 2-fold axis. The structure and atomic B-factors of peptide loops containing a reactive site were compared with that of adzuki bean Bowman-Birk type inhibitor in the complex with bovine beta-trypsin. This comparison shows that no significant structural change occurs in the reactive site of inhibitor at the formation of the inhibitor-protease complex, but structural rigidity around the reactive site seems to increase.

Amino Acid Sequence↗
PubMed1993

Induction of cytochrome P450 1A2 by musk analogues and other inducing agents in rat liver.

We characterized the inducing effects of two musk analogues, musk xylene and musk ambrette, on phase I and phase II drug-metabolizing enzymes in rat liver and compared their effects with 3-methylcholanthrene, isosafrole and 2(3)-tertbutylhydroxyanisole (BHA) at 0.1 mmol/kg dose level. Musk xylene and isosafrole increased more efficiently the metabolic activation of 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) to mutagen than that of benzo(a)pyrene. Musk ambrette increased both the activation of Glu-P-1 and benzo(a)pyrene to the same extent. Western blot analyses revealed that musk xylene, musk ambrette, isosafrole and BHA induced more strongly cytochrome P450 1A2 (CYP1A2) in microsomes than CYP1A1. 3-Methylcholanthrene induced CYP1A1 in preference to CYP1A2. On the other hand, all drugs except for 3-methylcholanthrene did not show remarkable increases in phase II enzyme activities, such as DT-diaphorase, glutathione S-transferase and UDP-glucuronyltransferase, at 0.1 mmol/kg dose level. These results show that musk xylene, musk ambrette, isosafrole and BHA at the dose level used in this study possess the potency to induce CYP1A2 without remarkable induction of CYP1A1 and phase II enzyme activities as observed for 3-methylcholanthrene, although they have been considered to induce both phase I and phase II drug-metabolizing enzymes at higher doses.

Animals↗
PubMed1993

Re-uptake of nascent low-density lipoproteins by HepG2 cells.

The kinetics and specificity of the interaction of nascent HepG2 LDL with the HepG2 LDL receptor were examined. 125I-Labeled HepG2 LDL and plasma LDL were bound by HepG2 cells in a specific and saturable manner at 4 degrees C. Competition studies with HepG2 LDL and plasma LDL indicated that both ligands bound to the same receptor. Scatchard analyses of the specific 4 degrees C-binding data revealed a Kd of 75 nM for HepG2 LDL and a Kd of 30 nM for plasma LDL suggesting that HepG2 LDL bind less efficiently to the HepG2 LDL receptor than plasma LDL. Binding, internalization and degradation studies carried out at 37 degrees C indicated that HepG2 cells are capable of catabolizing their own nascent LDL; however, under normal experimental conditions re-uptake of nascent LDL is quantitatively insignificant.

Binding, Competitive↗
PubMed1993

Esophagectomy for metastatic carcinoma of the esophagus from lung cancer.

A patient with metastatic carcinoma of the esophagus from lung cancer is reported. The patient was a 54-year-old woman who underwent a left lower lobectomy for lung cancer 5 years previously. The authors performed a thoracic esophagectomy, dissection of mediastinal lymph nodes, and reconstruction of the esophagus; the surgery was followed by chemotherapy. Because the histologic pattern of the esophageal tumor was similar to that of lung cancer and mucosal involvement was not seen, the esophageal tumor was interpreted to be a metastasis from lung cancer. The patient is well without recurrence of disease 23 months after operation. This is the first report of a successful esophagectomy for metastatic carcinoma of the esophagus from lung cancer.

Adenocarcinoma↗