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Biomedical subjects

H Hirose

Publications and source records attributed to H Hirose.

At least 199 records · Page 11Linked to original sources
PubMed1995

[A trial of antegrade perfusion to the lower half of the body with selective cerebral perfusion for repair of aortic arch aneurysm combined with atherosclerosis obliterance].

A 73-year-old man with aortic arch aneurysm combined with atherosclerosis obliterance underwent aortic arch replacement. As he had bilateral femoral artery obstruction, we instituted ECC with arterial perfusion through the ascending aorta. Then, the left ventricle started dilating due to mild degree of aortic regurgitation. So with selective cerebral perfusion, we perfused the lower half of the body through a Foley balloon catheter which was inserted from the aortic arch antegradely. We could perfuse with the catheter for 20 minutes for core cooling and then during repair until the catheter disturbed the operation. The Foley catheter had given us some difficulties for handling during the procedure. Based on this experience, we have made a catheter which had both a balloon for aortic occlusion and a tube for perfusion and which we could keep away from operative fields, similar to the way we used antegradely insertable aortic occlusion balloon catheter.

Aged↗
PubMed1995

[Coronary artery bypass grafting in cases with the atherosclerotic ascending aorta].

Among 172 cases of coronary artery bypass grafting, 9 cases (5%) revealed severely atherosclerotic ascending aorta. In 3 of the 9 cases, total aortic cross-clamping in the distal anastomoses of saphenous vein graft (SVG) and partial aortic clamp in the proximal anastomoses of SVG were performed. In 1 case with this technique, cerebral infarction was occurred. In 4 cases, total aortic cross-clamping in the distal and proximal anastomoses of SVG was performed. In 2 of these cases with this technique, cerebral infarctions were occurred. Hypothermic circulatory arrest was performed in 2 of the rest. In one case that was predicted to have atherosclerosis of ascending aorta prior to operation, the left internal thoracic artery was anastomosed to the left anterior descending, and SVG to the right coronary artery with hypothermia and ventricular fibrillation. And during the proximal anastomoses of SVG, hypothermic circulatory arrest without aortic clamping was initiated. In another case, atherosclerosis of ascending aorta was noted after aortic cross-clamping. Then the aorta was declamped, hypothermic circulatory arrest was established, the aorta was opened, the diseased segment was resected, and proximal anastomoses of SVG was performed to Dacron patch which was implanted for aortic wall. There were no cerebral infarction in last two patients.

Aged↗
PubMed1995

[Treatment of patients with chronic dissecting aortic aneurysm (DeBakey type IIIb) presenting with compromised renal perfusion].

We reviewed our experience for 6 patients of chronic dissecting aortic aneurysm (DeBakey type IIIb) with the false lumen extending into the abdominal aorta and the renal arteries being perfused from the false lumen. In three cases, whose abdominal aorta presenting with large aneurysmal lesions, we performed graft replacement of the thoracic descending aorta and abdominal aorta simultaneously. In other three cases, whose abdominal aorta presenting without aneurysmal lesions, and moreover age advanced or perioperative conditions poor, we performed graft replacement of thoracic descending aorta, using double barreled distal anastomosis technique to ensure of enough blood flow into both true and false lumens. All patients survived and there were no early postoperative complications. In 3 cases of thoracic aortic replacement alone, the mean follow-up term was 38 months, postoperative computed tomography showed neither apparent expansion of the false lumen nor compression of the true lumen of the abdominal aorta, and postoperative renal function were maintained. In conclusion, in treatment of chronic dissecting aortic aneurysm (DeBakey type IIIb) presenting with compromised renal perfusion, we considered that replacement of the thoracic descending aorta and abdominal aorta brings patient the most radical improvements. But in the patients, who are elder or in poor perioperative conditions, the replacement of thoracic descending aorta using double barreled distal anastomosis technique is one easier applicable and safer procedure to preserve the renal perfusion.

Adult↗
PubMed1995

Focused-ion-beam digging of biological specimens.

The focused ion beam (FIB) technique has been applied for digging damageable biological specimens of human hair and the housefly eye. Sharp cross-sections have been formed for these specimens and their cross-sectional structures have been observed in scanning ion microscope (SIM) images. The applicability of FIB has been confirmed for these biological specimens.

Animals↗
PubMed1995

Aniseikonia, metamorphopsia and perceived entoptic pattern: some effects of a macular epiretinal membrane, and the subsequent spontaneous separation of the membrane.

Following cryo surgery for retinal hole repair, visual effects in the senior author's eyes were caused by an epiretinal membrane. Subjectively, metamorphopsia was noted, and entoptically perceived radial striae were observed centred near fixation. After subsequent cataract surgery, metamorphopsia was not detectable. Several months later, the centre of the striate entoptic pattern was observed to be centered several degrees from fixation. Concurrently, loss of contrast in the central visual field was noted. In time, both the entoptic pattern and the contrast effects became less visible (contrast improved much faster). The epiretinal membrane had spontaneously separated from the fovea. Repeated measurements of aniseikonia were obtained before cataract surgery, and after cataract surgery both prior to, and after the separation of the epiretinal membrane. Inferences are drawn.

Aniseikonia↗
PubMed1995

Screening of patients with ischemic heart disease by transesophageal atrial pacing and the selection of surgical therapy: in patients with arteriosclerosis obliterans and aortic aneurysm.

This study evaluated (1) a screening method for ischemic heart disease (IHD) using transesophageal atrial pacing (TEP), and (2) the appropriate surgical therapy for patients with concomitant IHD which was evaluated on the basis of the coronary score (CS) by Leaman. Thirty-nine patients with arteriosclerosis obliterans of the lower extremities (ASO) and 35 with aortic aneurysm underwent TEP and coronary angiography (CAG). Coexistent IHD was diagnosed in 25 patients (64%) with ASO and in 14 (40%) with aortic aneurysm. Screening for IHD by TEP was 96% sensitive, 71% specific, and 87% accurate in patients with ASO, and 79% sensitive, 90% specific, and 86% accurate in patients with aortic aneurysm. Coronary artery bypass grafting (CABG) and peripheral arterial revascularization (PAR) were performed by one stage surgery in 3 patients with a CS of 16 or more. In 18 patients with a CS of 5.5 or less, only PAR was performed. One stage surgery was performed in 6 patients with aortic aneurysm. Four patients had a CS of 9.5 or more, and 2 patients with coexistent stenosis of the left anterior descending branch (LAD) had CS of 3.5 and 8, respectively. Repair of the aneurysm was undertaken in 5 patients with a CS of 8 or less without LAD disease. In patients with ASO showing a CS of 5.5 or less and in those with aortic aneurysm showing a CS of 8 or less (and without LAD disease), the only surgical procedure performed was either PAR or repair of the aneurysm. There were no complications attributable to IHD observed in these patients during the perioperative period.

Adult↗
PubMed1995

[A case of invasive thymoma with myasthenia gravis and pure red cell aplasia].

The patient was a 42-year-old man whose main complaints were ptosis, diplopia and muscle weakness. Chest X-ray film revealed a right hilar mass and chest CT showed a solid mass at right anterior superior mediastinum. Laboratory studies revealed myasthenia gravis (MG) on EMG and pure red cell aplasia (PRCA) on hematology. An extended thymectomy, including the thymoma, was performed. Thrombocytopenia appeared postoperatively, but it improved when a platelet transfusion was given. Steroid was administered for postoperative adjuvant therapy, and the MG and PRCA were alleviated. This rare case of simultaneous MG and PRCA as complications of a thymoma is reported.

Adult↗
PubMed1995

[Noninvasive detection of the limitation of simple cold storage of the heart by myocardial electrical impedance].

The purpose of this study was to determine if graft viability during simple cold storage can be monitored from alteration of myocardial electrical impedance. Twelve anesthetized dogs were underwent rapid cardiac extripation and were placed in simple cold storage. They were divided into two groups according to preserved solution. Group S was preserved in 12 hours in saline. Group U was preserved in 24 hours in the University of Wisconsin (UW) solution. Myocardial electrical impedance was measured serially by use of a LCR meter and analyzed the changes of myocardial resistivity during preservation. Myocardial specimens were taken for myocardial ATP measurement with high-performance liquid chromatography and for water content in two groups. Moreover in order to predict the cardiac function after transplantation in two groups, heterotopic cardiac transplantation in the neck was performed in mongrel dogs and left ventricular (LV) Emax was measured. Myocardial resistivity increased significantly until 5.5 hours in group S, 13 hours in group U. ATP remained above 50% at 5.5 hours in Group S, 13.7 hours in Group U. Resistivity increase rate was over 0.1 omega cm/min in the period ATP remained above 50%. Myocardial water content increased during preservation in group S, but did not in group U. There was no relationship between the increase of resistivity and myocardial water content. LVEmax at 120 min after reperfusion was over 90% of preischemic value in 4 hour preserved heart in saline and 12 hour preserved heart in UW. Measurement of myocardial resistivity during simple cold storage may be feasivle as a monitor of graft viability.

Adenosine Triphosphate↗
PubMed1994

Beta-cell lipotoxicity in the pathogenesis of non-insulin-dependent diabetes mellitus of obese rats: impairment in adipocyte-beta-cell relationships.

Hyperinsulinemia, loss of glucose-stimulated insulin secretion (GSIS), and peripheral insulin resistance coexist in non-insulin-dependent diabetes mellitus (NIDDM). Because free fatty acids (FFA) can induce these same abnormalities, we studied their role in the pathogenesis of the NIDDM of obese Zucker diabetic fatty (ZDF-drt) rats from 5 weeks of age (before the onset of hyperglycemia) until 14 weeks. Two weeks prior to hyperglycemia, plasma FFA began to rise progressively, averaging 1.9 +/- 0.06 mM at the onset of hyperglycemia (P < 0.001 vs. controls). At this time GSIS was absent and beta-cell GLUT-2 glucose transporter was decreased. The triacylglycerol content of prediabetic islets rose to 10 times that of controls and was correlated with plasma FFA (r = 0.825; P < 0.001), which, in turn, was correlated with the plasma glucose concentration (r = 0.873; P < 0.001). Reduction of hyperlipacidemia to 1.3 +/- 0.07 mM by pair feeding with lean littermates reduced all beta-cell abnormalities and prevented hyperglycemia. Normal rat islets that had been cultured for 7 days in medium containing 2 mM FFA exhibited increased basal insulin secretion at 3 mM glucose, and first-phase GSIS was reduced by 68%; in prediabetic islets, first-phase GSIS was reduced by 69% by FFA. The results suggest a role for hyperlipacidemia in the pathogenesis of NIDDM; resistance to insulin-mediated antilipolysis is invoked to explain the high FFA despite hyperinsulinemia, and sensitivity of beta cells to hyperlipacedemia is invoked to explain the FFA-induced loss of GSIS.

Adipocytes↗
PubMed1994

Another approach for aortic valve replacement through left thoracotomy.

We report a 54-year-old man with a history of esophagectomy and retrosternal esophagogastric anastomosis for esophageal cancer through right thoracotomy in whom cardiac failure developed due to aortic regurgitation. He underwent aortic valve replacement through a left thoracotomy with division of two great arteries and their strong traction toward the surgeon by stay sutures. He has been well for 3 years postoperatively in New York Heart Association class I.

Anastomosis, Surgical↗
PubMed1994

Effects of diazoxide on alpha- and beta-cell function in isolated perfused rat pancreas.

To elucidate the effects of diazoxide on insulin and glucagon secretion at normal, high and low glucose concentrations and 10 mmol/l arginine, we performed pancreatic perfusion experiments. The insulin secretion rate in response to 16.7 mmol/l glucose was dose-dependently suppressed by concomitant infusion of diazoxide (100 and 300 mumol/l). Both the first and second phases of glucose-stimulated insulin secretion were significantly reduced in the presence of diazoxide as compared with controls. Basal glucagon secretion rate at 5.6 mmol/l glucose was significantly reduced by the administration of both 100 and 300 mumol/l diazoxide. Furthermore, the glucagon secretion rate at a high glucose concentration (16.7 mmol/l) was significantly lower with 300 mumol/l diazoxide than in the control. The glucagon secretion rate with glucopenia (1.4 mmol/l) was also significantly lower with 100 and 300 mumol/l diazoxide than in the control. The insulin secretion rate in response to 10 mmol/l arginine was also dose-dependently suppressed by concomitant infusion of diazoxide. The glucagon secretion rate in response to 10 mmol/l arginine was, however, significantly higher with 100 mumol/l diazoxide while not being significantly different with 300 mumol/l diazoxide. These findings suggest that some mechanism(s) which can be inhibited by diazoxide is involved in glucagon, as well as insulin, secretion in isolated perfused rat pancreas.

Analysis of Variance↗
PubMed1994

Alpha- and beta-cell function in obese Zucker (fa/fa) rats: a study with the isolated perfused pancreas.

1. The effects of various stimuli, including changes in glucose concentration, arginine, tyramine and noradrenaline, on insulin and glucagon secretion were investigated using isolated perfused pancreata of obese and lean male Zucker rats at 12 months of age. 2. In Zucker fatty rats, the insulin secretion rate was significantly (P < 0.01) higher than that of lean rats at all glucose concentrations tested (8.3, 16.7 and 1.4 mmol/l). However, the integrated insulin secretory response to raising the glucose concentration from 8.3 to 16.7 mmol/l was almost absent in these rats. The glucagon secretion rates were significantly lower at 8.3 and 1.4 mmol/l glucose (P < 0.001 for both), and in responses to 10 micrograms/ml tyramine and 0.1 mumol/l noradrenaline (P < 0.05 for both), in Zucker fatty rats. Integrated insulin and glucagon responses to 10 mmol/l arginine were identical in the two groups. 3. Histopathological and immunochemical studies revealed hyperplasia of beta-cells and scattered alpha-cells in the enlarged islets of Zucker fatty rats. 4. These results suggest that, in Zucker fatty rats, the decreased glucagon secretion in the isolated perfused pancreas is attributable to changes in the environment of alpha-cells and/or the inhibitory effects of hypersecreted insulin.

Animals↗
PubMed1994

Suppression of allograft responses by combining alloantigen-specific i.v. pre-sensitization with suboptimal doses of rapamycin.

C57BL/6 (B6) mice were injected i.v. with class I H-2-disparate B10.QBR spleen cells (10(7)/mouse). This regimen, termed donor alloantigen-specific i.v. pre-sensitization (DSP), induced almost complete reduction of the anti-B10.QBR mixed lymphocyte reaction (MLR) that has been regarded to represent a cytotoxic T lymphocyte (CTL)-independent graft rejection pathway. Because the DSP regimen failed to affect the generation of CTL responses, it did not prolong graft survival. Repeated (four or 11 times) administration in vivo (during 5 or 18 days) of rapamycin at suboptimal doses (0.5-2.0 mg/kg/day) failed to eliminate the capacities to exhibit MLR as well as to generate CTL responses. The suppression of CTL responses was achieved only through the combination of these two treatments. It was also shown that prolongation of skin graft survival was not induced by either of a single DSP or rapamycin treatment alone, but by the combination of these. Potent suppression of CTL responses was also induced when a single DSP was combined with repeated injection of a suboptimal dose (0.75 mg/kg/day) of another immunosuppressive drug, FK506, instead of rapamycin. However, there was a substantial difference in cellular mechanisms underlying the suppression of CTL responses by the above two different combinations. Under conditions in which lymphoid cells from mice receiving the treatments with DSP plus FK506 failed to generate CTL responses, the addition of recombinant IL-2 (rIL-2) to cultures restored the CTL generation, suggesting that CTL precursors themselves are not attenuated by the combined treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Novel method to determine instantaneous blood volume in pulsatile blood pump using electrical impedance.

A novel real-time volumetric method was developed for a pulsatile pump. This method, the impedance method, used electrical impedance change in the blood chamber according to volume change while pumping. This method was evaluated with two kinds of air-driven diaphragm pumps. During in vitro tests, the impedance method indicated real-time volume change, and there was excellent correlation between computed stroke volume with the impedance method and measured stroke volume with the electromagnetic flowmeter. In chronic animal tests with goats and in a clinical case, the impedance method measured pump output accurately, and it detected diaphragm motion in real-time. In addition, excellent durability was seen. Full-fill to full-empty drive was realized accurately with this method. Application of the impedance method was easy, and it did not deteriorate native antithrombogencity of the pump. The impedance method is practical and useful to estimate the pumping condition of a pulsatile blood pump, especially a diaphragm pump. This method would be useful in clinical application.

Aged↗
PubMed1994

[Serotypes of urease producing Vibrio parahaemolyticus and their relation to possession of tdh and trh genes].

We analysed 467 isolates of Vibrio parahaemolyticus for possession of tdh/trh gene in comparison with urease production and serotypes. Strains possessing tdh+/trh-, tdh+/trh+, tdh-/trh-, and tdh-/trh- show positive urease production 2.1, 100, 65.7, 100%, respectively. Serotypes of O1:K69, O3:K6, O3:K72, O6:K18, O6:K46 and O1:KUT were frequently positive (100% except 91.7% of the latest one) in urease production. All isolates of O3:K6 prossessed trh, whereas all isolates of certain serotypes including O1:K69 and O3:K72 possessed both trh and trh and tdh genes. Among these, most of O1:K69 and O3:K72 were urease producer. From these results, we speculate that urease production is closely related to the presence of the trh gene or/and lesser production of TDH. We also found the new combination of serovar, O3:K25, O4:K37 and O13:K72 in Kanagawa phenomenon-positive strains.

Genes, Bacterial↗
PubMed1994

Effects of N-[(trans-4-isopropylcyclohexyl)-carbonyl]-D-phenylalanine (A-4166) on insulin and glucagon secretion in isolated perfused rat pancreas.

N-[(trans-4-isopropylcyclohexyl)-carbonyl]-D-phenylalanine (A-4166) has a structure which differs from those of other known blood glucose-lowering agents including sulfonylureas. It has been shown that oral administration of A-4166 exerts blood glucose-lowering effects in animal in vivo studies. In the present study, we investigated the effects of A-4166 on insulin and glucagon secretion at several glucose concentrations using isolated perfused rat pancreas preparations. Both 3.0 and 30 mumol/l A-4166 significantly stimulated insulin secretion as compared with basal levels at glucose concentrations of 8.0 and 11.0 mmol (p < 0.01 and p < 0.05, respectively). In contrast, glucagon secretion was not affected by administration of A-4166 up to 30 mumol/l at these glucose concentrations. At a glucose concentration of 5.6 mmol/l, neither 0.3 nor 3.0 mumol/l A-4166 produced significant changes in insulin and glucagon secretion. However, A-4166 at 30 mumol/l significantly stimulated insulin secretion and inhibited glucagon secretion as compared with basal levels (p < 0.01 and p < 0.01, respectively). We conclude that A-4166 at 3.0 and 30 mumol/l directly stimulates insulin secretion but has little effect on glucagon secretion in isolated perfused rat pancreas at glucose concentrations of 8.0 and 11.0 mmol/l. these results, taken together with previously published data, suggest that oral administration of A-4166 could be a useful strategy for stimulating endogenous insulin secretion in non-insulin-dependent diabetic patients.

Animals↗
PubMed1994

The roles of the posterior cricoarytenoid and thyropharyngeus muscles in whispered speech.

In order to clarify the nature of the physiological adjustment for the production of whispering, physiological studies were conducted on the glottal and supralaryngeal adjustments during whispering. The results indicate that for the production of whispering there is a necessary relationship between glottal adjustment and supralaryngeal adjustment in terms of the coordination between posterior cricoarytenoid muscle (PCA) and thyropharyngeus muscle (TP). Also, there might be a function switch in our brain which enables the speaking mode to change from ordinary to whispering, using the activation of PCA and TP, as a result of human evolution.

Arytenoid Cartilage↗