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Biomedical subjects

S Hara

Publications and source records attributed to S Hara.

At least 271 records · Page 15Linked to original sources
PubMed1995

Identification of the positions of disulfide bonds of chitinase from a marine bacterium, Alteromonas sp. strain O-7.

Extracellular chitinase from marine Alteromonas sp. strain O-7 is unique because of the activation by four major cations contained in sea water, such as Na+, K+, Mg2+, and Ca2+. The positions of S-S bonds of Alteromonas chitinase were identified. Alteromonas chitinase was fragmented by TPCK-trypsin and Staphylococcus aureus V8 protease. The amino acid and sequence analyses of three peptides showed that the positions of disulfide bonds are Cys(94)-Cys(99), Cys(174)-Cys(196), and Cys(386)-Cys(395).

Amino Acid Sequence↗
PubMed1995

Results of carinal resection for bronchogenic carcinoma.

Fifteen patients underwent carinal resection for lung cancer during the years of 1957 through 1993. All were males with ages ranging from 40 to 81 (mean 60.1) years old. Cell Types of the cancer were squamous cell carcinoma in 12 cases, adenocarcinoma in 2 and small cell carcinoma in one. In 14 of 15 cases there was cancerous invasion into the tracheal carina (T4) and one had no involvement of the carina (T3). Four patients had no lymph node metastasis (N0), 2 had hilar node metastasis (N1), 8 had ipsilateral mediastinal node metastasis (N2) and one had contralateral mediastinal node metastasis (N3). Operative procedures for carino-plasty were sleeve pneumonectomy in 3 cases, pneumonectomy with wedge resection of the carina in 3, sleeve resection of the carina followed by reconstruction of the carina (Montage type) in 8, and carinal resection with reconstruction of the one-stoma type in one. Two patients died within one month due to pneumonia or renal failure (13.3%). Postoperative complications occurred in 14 cases and bronchorrhea (n = 8), anastomotic stenosis (n = 5) and pneumonia (n = 4) were frequent. Excluding 2 operative deaths, 8 cases died from 2 to 37 months after operation (mean 13.1 months) and 5 are alive from 10 to 24 months without recurrences. Patients with squamous cell carcinoma with N0 or N1 had better prognosis.

Adenocarcinoma↗
PubMed1995

Regional lung function following upper sleeve lobectomy for bronchogenic carcinoma.

Regional lung function of the operated side following upper sleeve lobectomy (n = 8) and simple upper lobectomy (n = 7) for lung cancer was evaluated. Regional ventilation was studied with Krypton 81m and regional pulmonary blood flow was studied with Technetium 99m. Measurements were taken from 12 to 24 months after operation. The ventilation rate of the operated side following right upper sleeve lobectomy (n = 5) was 42.9 +/- 6.7% and the perfusion rate was 37.4 +/- 4.6%. The regional ventilation rate of the operated side after simple right upper lobectomy (n = 3) was 45.9 +/- 10.5% and the perfusion rate was 46.2 +/- 5.2%. For the patients with left upper sleeve lobectomy (n = 3), these ratios were 29.9 +/- 11.1% and 19.2 +/- 3.6%, respectively. For the patients with simple left upper lobectomy (n = 4), these ratios were 27.3 +/- 4.5% and 22.3 +/- 3.3%. There were no statistical differences between the group with upper sleeve lobectomy and that with simple upper lobectomy. Regional function improved gradually with time. In conclusion, the regional lung function of the operated side following sleeve lobectomy was well preserved and showed no difference when compared with the regional function after simple lobectomy for lung cancer.

Aged↗
PubMed1995

Relation between parathyroid hormone and cardiac function in long-term hemodialysis patients.

Radionuclide ventriculographic and echocardiographic assessments of left ventricular cardiac function were studied in 46 long-term maintenance hemodialysis patients, and comparison of cardiac function pre- and post-parathyroidectomy in 10 hemodialysis patients with secondary hyperparathyroidism was investigated. In long-term hemodialysis patients, impairment of cardiac function was observed in 80.4%. In an overall study of 46 patients, no correlation between intact parathyroid hormone (iPTH) level and left ventricular ejection fraction (LVEF) was observed, but a significant (p < 0.05) negative correlation was observed in patients with an iPTh blood level over 200 pg/ml. A negative correlation between fractional fiber shortening and an iPTh level over 200 pg/ml was observed (p < 0.05). There was neither a correlation between the iPTH level and left ventricular (LV) mass, nor was there a correlation between the iPTH level and wall thickness. After parathyroidectomy, systolic and diastolic blood pressure, cardiothoracic ratio, LVEF, and LV mass decreased significantly (p < 0.05), but no significant difference was detected in cardiac thickness. In summary, the present data suggest that high levels over 200 pg/ml of the iPTH in long-term hemodialysis patients adversely affect the myocardial function, induce cardiac hypertrophy and cause high arterial blood pressure. After parathyroidectomy, the cardiac function improved with a reduction of cardiac mass and an improvement of cardiac contraction.

Adult↗
PubMed1995

[Evaluation of the pulmonary vascular bed by digital subtraction angiography].

We studied the usefulness of digital subtraction angiography for evaluating the pulmonary capillary bed. Four individuals underwent the procedure. One was a healthy volunteer and the others were patients with chronic pulmonary emphysema. During catheterization, an 8 F balloon catheter was manipulated into the right pulmonary artery. A total of 20 ml of contrast material was injected at a rate of 10 ml/sec at full inspiration. In the normal subject, the capillary bed filled homogeneously and no defect was seen. In the patients, the pulmonary artery was nearly normal, but severe defects were observed in the pulmonary capillaries. Contrast resolvability was greater with digital subtraction pulmonary angiography than with pulmonary perfusion scintigraphy or pulmonary arteriography. This technique makes possible the visual evaluation of the pulmonary capillary bed.

Aged↗
PubMed1995

Inhibition of parathyroid hormone-related protein release by extracellular calcium in dispersed cells from human parathyroid hyperplasia secondary to chronic renal failure and adenoma.

The relationship between parathyroid hormone-related protein (PTHrP) release from parathyroid cells and extracellular calcium ion concentration was investigated in three cases of parathyroid hyperplasia secondary to chronic renal failure and in four cases of parathyroid adenoma. Amounts of PTHrP released from individual parathyroid cells dispersed from surgical specimens were estimated by cell immunoblot assay. Parathyroid cells from both hyperplasias and adenomas showed significant suppression in the release of PTHrP with increase in extracellular calcium ions, but the amounts of PTHrP released from adenoma cells were significantly larger than from hyperplasia cells. The maximal value for PTHrP released within 120 minutes from adenoma cells was 2.91 +/- 2.11 x 10(-2) fmol/cell ([Ca2+], 0.4 mmol/L), and the minimal value was 1.32 +/- 0.35 x 10(-2) fmol/cell ([Ca2+], 2.0 mmol/L). On the other hand, the maximal value for PTHrP released from hyperplasia cells was 1.79 +/- 1.56 x 10(-2) fmol/cell ([Ca2+], 0.4 mmol/L), and the minimal value was 0.32 +/- 0.19 x 10(-2) fmol/cell ([Ca2+], 2.0 mmol/L). These results demonstrate actual release of PTHrP from abnormal parathyroid tissues into the extracellular space with the response to extracellular calcium ions depending on the cell status. Given the lack of definite histological criteria to differentiate between hyperplasias and adenomas in the parathyroid gland, the presently demonstrated significant difference in the ability to release PTHrP is important in pointing to parathyroid hyperplasia secondary to chronic renal failure as a distinct pathological entity separate from parathyroid adenoma.

Adenoma↗
PubMed1995

Increase in oxygen tension after intraperitoneal N-methyl-DL-aspartate in rat cerebral cortex.

An oxygen electrode equipped with a thermocouple enabled us to determine the absolute oxygen tension (PO2) in brain regions by taking account of local changes in temperature. Under urethane anesthesia, the PO2 of rat cerebral cortex was significantly increased up to 90 min after N-methyl-DL-aspartate administration (200 mg/kg, i.p.). This suggests that stimulation of NMDA receptors enhances oxygen supply to the cerebrum in vivo.

Animals↗
PubMed1995

Interindividual variation in carboxylesterase levels in human liver microsomes.

Microsomal carboxylesterase activities in 12 human livers were determined using 10 kinds of carboxylesterase substrates (p-nitrophenylacetate, p-nitrophenylpropionate, p-nitrophenylbutyrate, butanilicaine, isocarboxazid, palmitoyl-coenzyme-A, malathion, clofibrate, acetanilide, and phenacetin). There were large individual differences in the 12 humans based on experimental results in the past several years in our laboratory. We found that all human liver microsomes have RH1-immunoreactive carboxylesterase, and the carboxylesterase content in liver also showed large individual differences. The RH1-immunoreactive carboxylesterase concentration correlated well with those of p-nitrophenylesters, clofibrate, butanilicaine, and isocarboxazid, and anti-RH1 immunoglobulin G strongly inhibited human liver hydrolase activity. These findings indicate that one major carboxylesterase isozyme that is immunoreactive with anti-RH1 in human liver microsomes has catalytic activity on major carboxylesterase substrates, and thus hydrolase activity in human liver depends on the expression level of this carboxylesterase isozyme. These observations should be useful in understanding the action of carboxylesterases on drug metabolism in humans.

Adult↗
PubMed1994

The cyclic AMP response element plays an essential role in the expression of the human prostaglandin-endoperoxide synthase 2 gene in differentiated U937 monocytic cells.

The promoter activity of 1432 bp upstream of the human prostaglandin-endoperoxide synthase 2 gene (PTGS2) was examined in differentiated U937 monocytic cells expressing prostaglandin-endoperoxide synthase 2 mRNA. Transient transfection experiments were performed using these cells and reporter vectors containing the upstream region of the gene with deletions or site-specific mutations and the luciferase gene. The deletion or destruction of the cyclic AMP response element (nucleotides -59 to -53) markedly reduced the promoter activity of this gene. Electrophoretic mobility shift assays showed that a nuclear protein(s) binding to the cyclic AMP response element was induced during monocytic differentiation of U937 cells. These results indicate that expression of the human prostaglandin-endoperoxide synthase 2 gene in differentiated U937 monocytic cells is regulated by the cyclic AMP response element.

Base Sequence↗
PubMed1994

Isolation and molecular cloning of prostacyclin synthase from bovine endothelial cells.

Prostacyclin synthase catalyzes the conversion of prostaglandin H2 to prostacyclin, which is a powerful vasodilator and the most potent natural occurring inhibitor of platelet aggregation. In the present study, we determined the amino acid sequence of bovine prostacyclin synthase by combined protein chemical and molecular cloning techniques. The enzyme was purified and characterized from bovine aorta microsomes, and the partial amino acid sequences were determined with the native enzyme and endoproteinase Lys-C-cleaved peptides. Using primers synthesized according to the amino acid sequences, cDNA coding for prostacyclin synthase was amplified by polymerase chain reaction with bovine endothelial cell poly(A)+ RNA and cloned into pBluescript II. Nucleotide sequence analyses of the cloned cDNA inserts revealed that cDNA for this enzyme contained a 1500-base pair open reading frame coding for a 500-amino acid polypeptide with a M(r) of 56,628. COS-7 cells transfected with an expression plasmid harboring this cDNA clone expressed prostacyclin synthase activity. The primary structure of the enzyme showed structural characteristics of cytochrome P450 and exhibited a 32% identity to that of human cholesterol 7 alpha-hydroxylase. However, the identity between the amino acid sequences of bovine prostacyclin synthase and human thromboxane synthase was only 16%, and no P450 showed an identity higher than 40%, suggesting that prostacyclin synthase represents a new family in the P450 superfamily. RNA blot analysis indicated that the mRNA for prostacyclin synthase from bovine endothelial cells showed a size of approximately 2.7 kilobases and that the mRNA level increased about 3-fold by treatment of tumor necrosis factor-alpha.

Amino Acid Sequence↗
PubMed1994

Molecular cloning and expression of human prostacyclin synthase.

The cDNA for human prostacyclin synthase was cloned by polymerase chain reaction using poly(A)+ RNA from human aortic endothelial cells according to the partial nucleotide sequence of prostacyclin synthase gene. The cloned cDNA with a size of 1977 base pairs contained a 1500 base pairs open reading frame which encoded a 500 amino acid protein sharing an 88% identity with bovine prostacyclin synthase. RNA blot analysis indicated that the size of major prostacyclin synthase mRNA of human aortic endothelial cells was approximately 6 kilobases and that its mRNA level was increased by interleukin 1 or interleukin 6 treatment. Moreover, tissue distribution study demonstrated that prostacyclin synthase mRNA is widely expressed in human tissues and is particularly abundant in ovary, heart, skeletal muscle, lung, and prostate. These results suggest a variety of physiological roles of prostacyclin in addition to the implications in the cardiovascular system.

Amino Acid Sequence↗
PubMed1994

Characterization of the human gene (PTGS2) encoding prostaglandin-endoperoxide synthase 2.

The human gene (PTGS2) encoding an inducible isozyme of prostaglandin-endoperoxide synthase (prostaglandin-endoperoxide synthase 2) that is distinct from the well-characterized and constitutive isozyme (prostaglandin-endoperoxide synthase 1), was isolated using a polymerase-chain reaction-generated cDNA fragment probe for human prostaglandin-endoperoxide synthase 2. Nucleotide sequence analysis of the entire human prostaglandin-endoperoxide-synthase-2 gene demonstrated that it is more than 8.3 kb in size and consists of ten exons; this gene is very similar to the murine and chicken prostaglandin-endoperoxide-synthase-2 genes. The structures of exons in the human prostaglandin-endoperoxide-synthase-2 gene were also similar to those of the human prostaglandin-endoperoxide-synthase-1 gene (PTGS1). However, the sizes of introns in the human prostaglandin-endoperoxide-synthase-2 gene were generally smaller than those of the human prostaglandin-endoperoxide-synthase-1 gene. Primer-extension analysis indicated that the transcriptional-start site is 134 bases upstream of the translational-initiation site. The sequence of the 1.69-kb region of nucleotides preceding the transcriptional-start site and the first 0.8-kb intron contained a canonical TATA box and various transcriptional-regulatory elements (CArG box, NF-IL6, PEA-1, myb, GATA-1, xenobiotic-response element, cAMP-response element, NF-kappa B, PEA-3, Sp-1 and 12-O-tetradecanoyl-phorbol-13-acetate-response element). The nucleotide sequence of the 5'-flanking region (275 bp) of the human prostaglandin-endoperoxide-synthase-2 gene showed 63% similarity to the sequence of murine prostaglandin-endoperoxide-synthase-2/TIS10 gene, but essentially no homology to the chicken prostaglandin-endoperoxide-synthase-2 gene, and human and murine prostaglandin-endoperoxide-synthase-1 genes. A fluorescence in situ hybridization study showed that the human genes coding for prostaglandin-endoperoxide synthase 1 (PTGS1) and prostaglandin-endoperoxidase synthase 2 (PTGS2) were mapped to distinct chromosomes 9q32-q33.3 and 1q25.2-q25.3, respectively, indicating that these genes are not genetically linked.

Amino Acid Sequence↗
PubMed1994

Abundant expression of thromboxane synthase in rat macrophages.

The cloned cDNA for rat thromboxane (TX) synthase with a size of 1851 bp contained a 1599-bp open reading frame which encoded a 533-amino acid protein sharing 79.7% identity with human TX synthase. RNA blot analysis was carried out with rat cells and tissues. Rat peritoneal macrophages most abundantly expressed mRNA for TX synthase, and its level was not changed by in vivo stimulation of casein. Bone marrow, spleen, lung and thymus also expressed the TX synthase gene. These findings suggest the possibility that TXA2 plays a role in the immune system.

Amino Acid Sequence↗
PubMed1994

Management of anastomotic complications after sleeve lobectomy for lung cancer.

One hundred twelve patients (102 male and 10 female) underwent sleeve lobectomy for lung cancer from January 1969 to December 1991. Bronchopleural fistula occurred in 6 (5.6%), bronchovascular fistula in 2 (1.8%), pulmonary arterial occlusion in 2 (1.9%), anastomotic stricture or stenosis in 7 (6.3%), and local recurrence in 7 patients (6.3%). Early repair of bronchopleural fistula combined with an omentopexy achieved permanent closure of the fistula. Two patients who underwent a completion pneumonectomy for a pulmonary arterial occlusion died of respiratory failure. Two patients experienced uncontrollable bleeding into the bronchial tree through a bronchovascular fistula and sudden death. Completion pneumonectomy is indicated for a stricture due to scar formation. If pneumonectomy is precluded by poor pulmonary reserve, endoscopic excision using biopsy forceps is an alternative. Endoscopic resection is the treatment of choice for suture granulomas. Complications associated with bronchial or vascular anastomoses are serious and frequently fatal.

Adult↗
PubMed1994

Effect of opioid peptide antisera on nitrous oxide antinociception in rats.

This study was performed to examine the effects of ICV injection of antiserum against beta-endorphin (beta-EP) or methionine-enkephalin (ME) on nitrous oxide-induced antinociception in rats using the hot plate test. The injection of beta-EP antiserum reversed the antinociceptive effect of nitrous oxide in a dose-related manner up to 200 micrograms/rat. However, antagonism of nitrous oxide by 400 micrograms beta-EP antiserum was comparable to that produced by 200 micrograms. On the other hand, similar amounts of ME antiserum had little effect against nitrous oxide antinociception. These findings suggest that beta-EP may play an important role in the antinociceptive effect of nitrous oxide.

Analgesics↗