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Biomedical subjects

S Nemoto

Publications and source records attributed to S Nemoto.

At least 19 recordsLinked to original sources
PubMed1996

Interactions of the F1-ATPase subunits from Escherichia coli detected by the yeast two-hybrid system.

Subunit interactions among the F1-ATPase subunits were studied by the yeast two-hybrid system. Various pairwise combinations of genes encoding alpha, beta, gamma, delta and epsilon subunits of Escherichia coli H+-ATPase fused to the DNA-binding or activation domain of the yeast GAL4 gene were introduced into yeast and expression of a reporter gene encoding beta-galactosidase was detected. Combinations of the alpha and beta subunit genes, and of the epsilon and gamma subunit genes showed high levels of reporter gene expression, while those of alpha and delta, beta and delta, gamma and delta, and delta and epsilon demonstrated weak but significant reporter gene expression. However, combinations of alpha and gamma, beta and gamma, alpha and epsilon, and beta and epsilon did not induce reporter expression. None of the fused genes alone induced reporter gene expression. These results suggested that specific and strong interactions between the alpha and beta, gamma and epsilon, and weak interactions between the alpha and delta, beta and delta, and gamma and delta subunits occurred in yeast cells in the two-hybrid system. Effects of previously identified mutant beta subunits with Leu-40 to Pro. Glu-41 to Lys or Pro-332 to Gln substitutions which caused defects in molecular assembly of F1-ATPase were analyzed with regard to alpha-beta interactions. No interaction of the alpha and beta subunits was observed in this system using the beta subunit with mutation of Pro-332 to Gln. However, for the other two mutations, alpha-beta interactions were observed. This system may be useful for isolating mutants which have defects in interaction of F1-ATPase subunits.

Escherichia coli↗
PubMed1996

A cervical dural arteriovenous fistula in a patient presenting with radiculopathy. Case report.

A 51-year-old man presenting with radiculopathy a rare cervical dural arteriovenous fistula (AVF) is reported. Angiography revealed that the cervical dural AVF was fed mainly by the left C-3 and C-4 radicular arteries and drained into the internal vertebral venous plexus with no communication with intradural structures. The dural AVF was treated surgically after embolization therapy. Although the AVF showed mass effect on computerized tomography (CT) scanning, abnormal vessels, which were suspected to drain the AVF, were observed intraoperatively to compress the left C-4 and C-5 nerve root sleeves. After resection of these abnormal epidural vessels, monoparesis of the left proximal upper extremity was markedly improved. In this patient, dynamic CT scanning was useful in the initial diagnosis, and the preoperative embolization therapy was very effective.

Arteriovenous Fistula↗
PubMed1996

[Comparison of fetal circulatory responses during maternal bleeding and fetal bleeding].

The purpose of this study was to compare the fetal circulatory responses during maternal hemorrhage and fetal hemorrhage. Four pregnant goats, gestational age 131 +/- 7 days for the fetal hemorrhage and 5 goats, 132 +/- 2 days (term 145 days) for the maternal hemorrhage were used. The amounts of hemorrhage were 700ml per 2 hours for the maternal hemorrhage and 40ml per 2 hours for the fetal hemorrhage. Although fetal arterial pH decreased during both hemorrhages, fetal arterial pO2 increased during the fetal hemorrhage and decreased in the maternal hemorrhage. The fetal arginine vasopressin concentration and plasma renin activity increased during both hemorrhages, but the rates of change in the hormone concentrations were higher during the fetal hemorrhage. The fetal aldosterone concentration decreased during maternal hemorrhage but increased during fetal hemorrhage. FAP increased and FHR decreased during maternal hemorrhage. FAP and FHR were significantly correlated to the AVP concentration. These relationships were not found during fetal hemorrhage. We therefore concluded that fetal responses were completely different in pO2, FAP and FHR during the maternal and fetal hemorrhages.

Aldosterone↗
PubMed1995

Long-term results of aortic valve translocation for mycotic periannular abscess: comparative study of Danielson's original method and our threadless method.

Between June, 1983, and October, 1992, we performed Danielson's original translocation method in four patients (group I) and our translocation method in seven patients (group II), for the treatment of active periannular abscess. There were no perioperative or hospital deaths in either group. The long-term results of these two groups are compared in this report. There were four late deaths (mortality rate 100%) in group I, and three late deaths (mortality rate 43%) in group II. The causes of death were cardiac in six patients and noncardiac in one patient. Vein graft failure occurred in one group I patient (25%) and in two group II patients (28%). Rupture or aortic pseudoaneurysm formation occurred in three group I patients (75%). These findings suggest that our threadless method may be superior to Danielson's original translocation method. Therefore, with close observation, especially of saphenons vein great (SVG) failure, arterial graft use could be acceptable for translocation.

Abscess↗
PubMed1995

[Stanford type A acute aortic dissection involving an aberrant right subclavian artery--a successful operative case].

A 64-year-old woman was admitted with chest (pain) and back pain. We found aortic dissecting area from ascending aorta to aortic arch and thoracic descending aorta by enhanced computed tomography. She was diagnosed Stanford type A acute aortic dissection. Emergent operation was performed on Jan. 20th, 1994. During operation, we found an aberrant right subclavian artery from Jan. 20th, 1994. During operation, we found an aberrant right subclavian artery from descending aorta. Using non-clamping selective cerebral perfusion, we could succeed this operation. As far as we know, this is the first report in Japanese literatures.

Acute Disease↗
PubMed1995

[The experience of mitral valve repair for valve regurgitation].

Between November 1993 and March 1995, 10 patients underwent mitral valve repair. Six of them were performed with McGoon's procedure for prolapsed posterior leaflet. Two of them were performed chodal reconstruction with PTFE sutures for prolapsed anterior leaflet. A patient received McGoon's procedure of posterior leaflet and chodal reconstruction of anterior leaflet. A patient of ischemic mitral regurgitation underwent mitral annuloplasty. There were no operative and late deaths. The MR disappeared or improved to grade I in 9 patients. A patient with McGoon's procedure had hemolytic anemia and required reoperation.

Adult↗
PubMed1995

[Use of intravenous hyperalimentation catheter to drainage prolonged postoperative pleural effusion after harvesting the internal thoracic artery].

Increased chest drainage, a higher incidence of pleural effusions in the postoperative period, and more chest tube drainage was found after harvesting the internal thoracic artery (ITA). Patients with these complications required thoracocentesis, or prolonged chest tube drainage. But these methods may be painful and make a limitation to activity of daily life (ADL) in these patients. We therefore sought an effective procedure for these patients, and applied pleural placement of intravenous hyperalimentation catheter. This technique could drain the effusion completely, conveniently and painlessly without a limitation to ADL. Pneumothorax, infections and other complications occurred in no patients. We concluded that this method might be useful in these patients with prolonged post operative pleural effusion after harvesting the ITA who have failed other modes of therapy.

Aged↗
PubMed1995

[Geometrical study on intra-arterial aortoinfundibuloplasty].

Newly-developed procedure for aortic annular enlargement was geometrically examined on its optimal annular augmentation. Valve prosthesis is accommodated by anterior annular split extending into aortopulmonary and infundibular septum and, eventually, protrudes into pulmonary valvular orifice in this procedure. Relationship between residual pulmonary valvular area (PVA) and aortic annular incremental radius (x) is given by: PVA = (r+x)2 [pi - 2 pi x/(r+x) + sin (2 pi x/(r+x))], where r is original aortic annular radius. Optimal aortic annular augmentation maximizing PVA and saving original PVA is 1.33 times and 1.70 times of original diameter respectively. Animal experiments employing six mongrel dogs demonstrated no significant increase of systolic peak pressure gradient in right ventricular outflow tract after the procedure standardized by this geometrical idea. Our procedure would bear radical enlargement of small aortic annulus.

Aortic Valve↗
PubMed1995

[The modified Bentall's operation for the prosthetic valve malfunction with annuloaortic ectasia due to aortitis syndrome--a successful case of the operation on steroid therapy].

A 23-year-old female was undergone the modified Bentall's operation for the prosthetic valve malfunction with annuloarotic ectasia due to aortitis syndrome. For she was in active inflammatory phase at the first admission to our hospital, the glucocorticoid steroid therapy was started to control the inflammation. After the good control was induced, the re-operation was done. In the operation, the prosthetic valve was detached from the annular ring and the motion was restricted by small thrombus and the remnant of right coronary cusp, and the right coronary orifice was not noticed. The right coronary artery was not able to be reconstructed, and slightly ischemic change was occurred postoperatively. She was treated by glucocorticoid steroid also in the postoperative period. Her postoperative course has been uneventful of three years.

Adult↗
PubMed1995

[Experimental study on organ perfusion by intraaortic balloon counterpulsation with double balloon catheter].

Newly-developed catheter for the intraaortic balloon counterpulsation with cardio-renal assist was examined on animal model. The catheter consists of two balloon segments between which the celiac trunk, the superior mesenteric artery and the renal artery are to be placed. Statistical comparison on each hemodynamic element was carried out between the catheter (DBC), conventional single balloon catheter (SBC) of the same balloon volume as DBC and no assist (None) groups. There were no significant changes between SBC and DBC in cardiac output, femoral arterial flow and central venous pressure. Renal arterial flow and urinary output were significantly increased in DBC (None 14.4 +/- 3.9, SBC 22.6 +/- 5.6, DBC 31.0 +/- 6.9 ml/min in renal arterial flow, None 33 +/- 9, SBC 64 +/- 14, DBC 78 +/- 20 ml/h in urinary output, p < or = 0.05). After the remodeling adjust to the human stature, a clinical application would be considered.

Animals↗
PubMed1995

[Surgical results of aortitis syndrome (Takayasu disease) combined with annuloaortic ectasia].

From March 1973 to December 1994, 8 patients (2 males and 6 females) aged 34.4 +/- 7.8 years, underwent composite graft replacement (CGR) for aortitis syndrome combined with annuloaortic ectasia (AAE) in our institute. Five patients showed active aortitis syndrome and steroid therapy was administrated to 2 of them. The mean value of the C-reactive protein (CRP) was 1.6 +/- 1.8 before the operation. The maximum diameter of the ascending aorta was 67.1 +/- 10.3 mm (range 53 to 85 mm). Stenosis and/or ectasia of the neck vessels were recognized in 5 cases, as well as the coronary artery in 2 cases. Isolated CGR was performed in 6 cases, and combined with single CABG to LAD in 1 case and with total arch replacement in 1 case. The enlarged ascending aorta was replaced with main graft using the exclusion method and interposed grafts for coronary arteries were sutured with pledgetted mattress sutures all around the coronary ostia. In patients with stenosis of neck vessels, oxygen saturation of the jugular vein was monitored during extracorporeal circulation for surveillance of cerebral ischemia. There was 1 early death due to pulmonary failure. Seven cases survived without any complications during 4-132 months (mean 83.4 months) of the follow-up period. After the operation, 3 cases required steroid therapy during 4-50 months. We concluded that preoperative control of active inflammation, selection of operative procedures, timing for the operation, and the long-term precise management of the intractable disease were essential for successful treatment of aortitis syndrome with AAE.

Adult↗
PubMed1994

Artificial parthenogenesis in starfish eggs: behavior of nuclei and chromosomes resulting in tetraploidy of parthenogenotes produced by the suppression of polar body extrusion.

Artificial parthenogenesis in starfish requires the activation of oocytes and the suppression of the polar body (PB) extrusion. To induce parthenogenesis we have employed a combination of calcium ionophore A23187 for activating oocytes and cytochalasin B (CB) for the suppression of PB extrusions. The treatment of activated oocytes with CB during meiosis I produced eggs lacking polar bodies, i.e., during meiosis I produced eggs lacking polar bodies, i.e., 0pb eggs, and treatment during meiosis II induced eggs bearing the first PB only, i.e., 1pb eggs. About 90% of both 0pb and 1pb eggs developed parthenogenetically with strong synchrony of cell division among eggs. After meiotic chromosomes in CB-treated oocytes separated finally into monads, they came together to form a single nucleus. The nucleus was found to be tetraploid in the 0pb eggs and diploid in the 1pb eggs. Regardless of the difference in ploidy, both 0pb and 1pb eggs developed as tetraploid embryos. Observations of the behavior of meiotic chromosomes and nuclei revealed that in the 0pb eggs, the first round of chromosomal replication was followed by the first cleavage, as in normally fertilized eggs. In the 1pb eggs, on the other hand, two rounds of chromosomal replication were found to precede the first cleavage, indicating the occurrence of one (first) round of chromosomal replication that is not accompanied with cytokinesis. In the first round of mitosis, a bipolar spindle did not appear, but only a half spindle was formed, resulting in the failure of both karyokinesis and cytokinesis. Thus, both types of parthenogenetic eggs became tetraploid before the first cleavage. At the first cleavage, both types of eggs formed a bipolar spindle and divided into a pair of blastomeres. Based on these observations, we suggest that the meiotic centrosomes remaining in these eggs by the failure of PB extrusion are diverted into mitosis-organizing centers in the mitotic spindle, and this results in parthenogenetic development.

Animals↗
PubMed1994

Preoperative embolization for paraganglioma.

We have applied a new method of preoperative embolization to an intravagal and to carotid body paraganglioma, using estrogen dissolved in absolute alcohol and polyvinyl alcohol particles, which diffusely embolizes vessels from capillaries to main feeders. Total resection of the tumors after embolization was successively performed without postoperative complications; total blood loss was 205 and 130 ml, respectively, and the surgical time was approximately 3 hours in both cases. The technique, characteristics, and advantages of this method are discussed.

Angiography↗
PubMed1994

Effects of 2-buten-4-olide, an endogenous satiety substance, on plasma glucose, corticosterone, and catecholamines.

Effects of 2-buten-4-olide (2-B4O), an endogenous satiety substance, on levels of plasma glucose, corticosterone, and catecholamines were examined in fed, conscious, and unrestrained rats. A vascular indwelling catheter was inserted into the right atrium of the animal from the jugular vein 1 wk before the experiment. Injection of 2-B4O and blood sampling were performed through the catheter in an unanesthetized condition. The levels of plasma glucose, corticosterone, epinephrine, and norepinephrine increased significantly for 2 h after the start of intravenous injection of 2-B4O in a dose-dependent manner. The increases in glucose and catecholamines induced by 2-B4O injection were abolished by bilateral splanchnicotomy (SPX) but not by pretreatment with anti-corticotropin-releasing factor (CRF) antibody. The increase in corticosterone was abolished not by the SPX but by pretreatment with anti-CRF antibody. These findings suggest that 2-B4O, endogenously produced during food deprivation, may facilitate sympathoadrenal and hypothalamopituitary-adrenal functions through the central nervous system.

4-Butyrolactone↗
PubMed1994

Urinary excretion level of hydroxylysylpyridinoline as an index of bone resorption.

Hydroxylysylpyridinoline (HP), an intermolecular cross-linking amino acid, is present only in bone and cartilage collagen. We examined urinary HP levels in order to assess bone collagen metabolism using HPLC. Urinary HP excretion levels (nmol/mmol creatinine) of healthy control groups gradually increased with aging. Urinary HP excretion levels of females were higher than those of age-adjusted males. On the other hand, the urinary excretion levels of HP in osteoporotic patients were significantly higher than those of age and sex-adjusted controls. It is suggested that the determination of urinary HP excretion levels is useful in the clinical evaluation of metabolic bone diseases, especially osteoporosis.

Adult↗
PubMed1994

Role of hydrogen peroxide in the inhibitory effect of ascorbate on cell growth.

Organ cultures have become an important method for the study of some of the biochemical reactions in which ascorbate takes part, and there are conflicting views on the stimulatory and inhibitory actions of ascorbate on cell growth. This study aimed to clarify the inhibitory mechanism of ascorbate using 3T6 fibroblasts. Cells were exposed to ascorbate at various concentrations in medium. The results showed that 3T6 fibroblasts were killed in medium containing more than 0.3 mM ascorbate. This lethal effect of ascorbate on cells was inhibited by the addition of catalase, an enzyme that decomposes hydrogen peroxide (H2O2), to the medium. When the medium with ascorbate was incubated in the absence of cells, the amount of H2O2 generation depended on the ascorbate concentration, and decreased in inverse proportion to the serum concentration added to the medium. The addition of albumin, which is the main protein in serum, also inhibited H2O2 generation in the medium with ascorbate. However H2O2 generation was not inhibited completely by serum and albumin. These results indicate that cytotoxicity of ascorbate is induced by H2O2.

3T3 Cells↗
PubMed1994

[Is extensive usage of arterial grafts in revascularization of the circumflex appropriate?: comparative study with the saphenous vein].

From September 1975 to March 1992, 584 patients underwent coronary artery bypass grafting (CABG) including revascularization of the circumflex artery (LCX) with either saphenous vein (Group S, n = 496) or arterial grafts (Group A, n = 88). Group S was divided into two subgroups. Group S I is the patients who underwent CABG before April 1988, when the first case of arterial revascularization of the LCX, and Group S II is the patients who underwent CABG after April 1988. No significant differences were noted in early mortality, late mortality, or event free curve among three groups. Although graft flow was significantly less in Group A (27.8 +/- 12.8 ml/min) than Group S (60.0 +/- 35.7 ml/min), the patency rate was better in Group A (94.3%) than Group S I (88.6%) or Group S II (87.7%). The proportion of usage of arterial grafts in revascularization of the left anterior descending artery (LAD) was smaller in Group A (65.5%) than Group S II (80.3%), but the patency rate was acceptably good in both groups (Group A: 98.8%, Group S II: 99.5%). These findings justify extensive usage of arterial grafts to the LCX area under proper assignment of grafts to obtain good patency rate and long-term results with keeping quality of revascularization of the LAD area.

Abdominal Muscles↗