Biomedical subjects

S Murakawa

Publications and source records attributed to S Murakawa.

At least 19 recordsLinked to original sources

PubMed2001

Increases in plasma ACTH and cortisol after hypertonic saline infusion in patients with central diabetes insipidus.

To clarify the mechanism for the potentiation of CRH-induced ACTH response by the infusion of hypertonic saline, we investigated changes in plasma ACTH concentration after infusion of 5% hypertonic saline in five patients with untreated central diabetes insipidus (DI). Basal levels of plasma ACTH and cortisol in the DI group were not significantly different from those in normal control subjects. The infusion of hypertonic saline produced an increase in plasma arginine vasopressin (AVP) in controls, but did not elevate ACTH. However, in patients with DI, the plasma AVP concentration did not change, but circulating ACTH increased 3.6-fold (7.7 +/- 1.5 to 23.0 +/- 2.7 pmol/liter; P < 0.01), and plasma cortisol also increased significantly (298 +/- 99 to 538 +/- 124 nmol/liter; P < 0.05). Moreover, a positive correlation was observed between plasma ACTH and osmolality (r = 0.72; P < 0.005). These results indicate that ACTH secretion in DI patients is regulated by a mechanism distinct from that in healthy subjects. It seems possible that the increase in plasma osmolality promotes ACTH secretion in DI patients through AVP and/or urocortin via the hypophyseal portal system, independent of the AVP secretion from magnocellular neurons.

Adrenocorticotropic Hormone↗

PubMed1999

Predictability of dielectric properties for ischemic injury of the skeletal muscle before reperfusion.

OBJECTIVE: The purpose of this study is to assess whether or not dielectric properties could predict the severity of ischemic injury of the skeletal muscle before reperfusion to prevent the myonephropathic metabolic syndrome (MNMS). METHODS: Japanese White rabbits were anesthetized and their hind limbs were subjected to 0, 2, 4, and 6 h of ischemia and then 10 h of reperfusion (n = 4, 5, 6, and 6). Dielectric properties of the gastrocnemius muscle were measured and tan delta(m) and D were calculated from them. To assess ischemic injury, we also measured (a) creatine phosphate kinase (CPK) and aldolase, (b) spectrophotometric assay of triphenyltetrazolium chloride assay, and (c) histological evaluation by H & E staining, 10 h after reperfusion. RESULTS: The tan delta(m) increased and D decreased significantly compared with those in preischemia (P < 0.01). The tan delta(m) value just before reperfusion significantly correlated positively with the maximum value of CPK (CPK(max)) or the maximum value of aldolase (ALD(max)) (r = 0.73, 0.69) and negatively with %TTC (r = 0.66). The D value just prior to reperfusion significantly correlated negatively with CPK(max) and ALD(max) (r = 0.81, 0.86) and positively with %TTC (r = 0.79) after reperfusion, respectively. Histologically, skeletal muscle necrosis was detected in 11 out of 12 skeletal muscles with tan delta(m) values which were 3.70 or more and 11 out of 14 muscles with D values which were 1.47 or less. CONCLUSION: The severity of skeletal muscle ischemic injury can be evaluated before reperfusion by measuring the dielectric properties during ischemia.

Animals↗

PubMed1999

[Intratumoral ethanol injection therapy using endoscopic video information system].

Bronchoscopic ethanol injection (BEI) therapy for endobronchial malignant tumor is thought to be an effective modality for airway dilatation and hemostasis without expensive special equipment. But if ethanol leaks into the airway, it causes severe coughing and erosion of bronchial wall. Using endoscopic video information system (EVIS), an assistant operator can observe an ethanol leak and inject an adequate volume. To evaluate the efficacy and adverse effect of BEI therapy, we treated 8 patients with endobronchial malignant tumor using EVIS. Under local anesthesia, a video-bronchoscope (Olympus BF200 or BF 1T200) was inserted orally, a transbronchial aspiration cytology (TBAC) needle was inserted via the biopsy channel, and injections of 0.2 ml of 99% ethanol into the tumor were repeated. After the tumor degenerated to necrotic tissue, it was removed with a biopsy forceps, and this maneuver was repeated for the existing fresh lesion. The total volume of injected ethanol was 4.5 + 1.6 ml (mean + SD). Airway obstruction and atelectasis were relieved in 4 cases, and hemostasis was obtained in 2 cases. In 2 cases, airway dilatation and hemostasis were not obtained. BEI was more effective in the patients with polypoid or nodular tumor protruding into the airway lumen. As for adverse effects, ethanol leaks caused a severe cough in 2 cases, although they were tolerable and treatment could be continued. BEI therapy using EVIS was thought to be useful to control airway obstruction by endobronchial polypoid tumor with good cost-effectiveness and fewer adverse effects.

Bronchial Neoplasms↗

PubMed1999

[The experience of telemedicine transmitting CT image of ruptured thoracic aortic aneurysm on the Internet].

The report describes our experience in establishing CT image transmission of ruptured thoracic aortic aneurysm to Gifu university hospital on the Internet. In this emergent case CT image transmission to the cardiovascular surgent provided medical informations in detail, which is very useful to decide the operative method and to prepare the assist circulation devices for the operation before the patient get to the hospital by ambulance. The Internet may prove to be major vehicle for telemedicine, consulting the professionals located in remote clinical institute.

Aged↗

PubMed1998

Evaluation of ischemic damage in the skeletal muscle with the use of electrical properties.

We performed experimental and clinical studies with measurement of electrical character in the skeletal muscle to assess ischemic damage and reperfusion injury in lower limbs. In 14 dogs, the bilateral hind limbs were squeezed at the inguinal region to make ischemia and they were reperfused after various intervals. Conductivity (G) of the skeletal muscles in hind limbs was measured with an LCR meter, which is an impedance analyzer. Change of G from 0 to 3 h of reperfusion (Delta3G) was calculated. G was decreased during ischemia and increased after reperfusion. In those whose Delta3G as more than 2.1 mS/cm, serum creatine kinase and aldolase at 10 h after reperfusion were correlated significantly (P < 0.01) to Delta3G. In patients with an abdominal aortic aneurysm (N = 3), arteriosclerosis obliterans (N = 1), or acute arterial occlusion (AAO, N = 1), G of lower extremities was measured from arterial clamp to declamp. Conductivity markedly increased after reperfusion and serum creatine kinase was the highest in the patient with AAO. We suggested that measurement of G may provide monitoring of ischemic and reperfused phase injury in the skeletal muscle and may be applicable to prediction of the skeletal muscular reperfusion injury.

Animals↗

PubMed1998

[Reoperation for diffuse supravalvular aortic stenosis with Williams syndrome--extended patch aortoplasty and extra-anatomic bypass from the ascending aorta to the descending aorta in a median sternotomy].

A case of diffuse supravalvular aortic stenosis (SVAS) with Williams syndrome is reported. In this case of severe diffuse SVAS, we performed the diamond-patch aortoplasty in a child. However he has been suffering from residual SVAS. At 9-years old, the myocardial injury was noted by myocardial scintigraphy. Preoperative cardiac catheterization and angiography revealed the hypoplastic ascending aorta and arch with a pressure gradient of 89 mmHg at the distal site from the left subclavian artery. Through only a median stenotomy, an extended patch aortoplasty between the valsalva sinus and distal arch was performed and an extraanatomic bypass from the ascending aorta to the descending aorta was employed using a 10 mm tube graft. We realize this technique is available because this method can relieve the left ventriculus of the pressure load and operate via only median sternotomy.

Aorta↗

PubMed1998

Primary cardiac leiomyosarcoma growing rapidly and causing right ventricular outflow obstruction.

Leiomyosarcomas are extremely rare primary cardiac tumors. We report a rapidly growing primary leiomyosarcoma of the right ventricle, which obstructed the right ventricular outflow tract within one month after symptom onset in a 68-year-old man. Two-dimensional echocardiography was useful in diagnosing the extent and progression of the tumor. The tumor was surgically resected on an emergency basis, and the right ventricle and pulmonary artery were successfully reconstructed. Recurrence of the tumor on the right ventricle was observed, and the patient was overcome by sudden dyspnea and died three months after surgery.

Aged↗

PubMed1997

Direct recognition of rat MHC antigens on rat antigen-presenting cells by mouse CD4+ and CD8+ T cells and establishment of T cell clones exhibiting a direct recognition pathway.

Alloantigens are recognized by T cells either through a direct pathway, which involves recognition of alloantigens expressed on allogeneic antigen-presenting cells (APC), or through an indirect pathway, which involves recognition of processed alloantigens presented by self APC. We investigated whether rat xenoantigens are also recognized by direct (xenogeneic APC-restricted) and/or indirect (self APC-restricted) pathways. C57BL/6 (B6) mouse anti-F344 or WKAH rat mixed lymphocyte reactions (MLRs) were partially inhibited by addition of either anti-mouse CD4 or CD8 monoclonal antibody (mAb) and almost completely blocked in the presence of both mAbs. These xenogeneic MLRs were almost completely inhibited by simultaneous depletion of both self and xeno APCs and only partially suppressed by the elimination of either type of APC, indicating that freshly prepared splenic mouse T cells can recognize rat xenoantigens through both direct and indirect pathways. Anti-F334 T cell lines were generated from B6 anti-F344 MLR cultures, and four CD4+ and four CD8+ T cell clones were isolated from these parental lines. The parental lines and those derived T cell clones were tested for their ability to proliferate depending on the presence of F344 APC. Proliferation of CD8 clones by stimulation with F344 APC was inhibited by the addition of anti-rat class I MHC mAb but not of anti-class II MHC mAbs. Conversely, proliferation of CD4 clones was reduced by addition of anti-class II MHC mAbs. Thus, these results indicate that xeno (rat)-reactive mouse T cells recognize xenoantigens via both indirect (self APC-restricted) and direct (xeno APC-restricted) pathways and that both CD4 and CD8 subsets of T cells participate in a direct pathway of xenoantigen recognition.

Animals↗

PubMed1997

Effects of wrapping tightness on acute cardiac function in dynamic cardiomyoplasty.

BACKGROUND: It has not been clarified how tightly the heart should be wrapped for maximal augmentation of cardiac function in cardiomyoplasty. METHODS: Hearts in acute failure induced by propranolol were wrapped with the left latissimus dorsi muscle, loosely (loose CMP), moderately (moderate CMP), and tightly (tight CMP) in each of 5 pigs. To measure the pressure between the latissimus dorsi muscle and the left ventricle (LV), a Millar pressure catheter with a latex balloon was placed on the anterior wall of the LV. Left ventricular wall tension was calculated according to Laplace's law, using the difference between the LV pressure and the balloon pressure. RESULTS: In the loose CMP, moderate CMP, and tight CMP groups, the mean balloon pressures during unassisted beats were 8.2, 10.4, and 13.2 mm Hg, respectively. During unassisted beats, the mean LV wall tension values were 38,683, 29,938 (p < 0.05 versus loose CMP), and 26,652 (p < 0.05 versus loose CMP) dynes/cm, respectively, the peak LV pressures were 76.8, 73.8, and 65 (p < 0.05 versus loose CMP) mm Hg, respectively, and the stroke volumes were 12.8, 9.2, and 8.5 (p < 0.05 versus loose CMP) mL, respectively. During assisted beats, the mean LV wall tension values were 20,059, 11,290, and 7,893 (p < 0.05 versus loose CMP) dynes/cm, respectively, the peak LV pressures were 94.1, 98.1, and 92.0 mm Hg, respectively, and the stroke volumes were 13.8, 11.6, and 9.4 (p < 0.05 versus loose CMP) mL, respectively. CONCLUSIONS: During unassisted beats, tight CMP (13 mm Hg) had the advantage of diminishing LV wall tension, but the disadvantage of diminishing LV pressure and stroke volume, compared with loose CMP (8 mm Hg). Moderate CMP (10 mm Hg), however, had the advantage of diminishing LV wall tension without a decrease in LV pressure and stroke volume.

Animals↗

PubMed1997

Blood supply to the latissimus dorsi muscle and muscle performance during co- or counterpulsatile stimulation for circulatory assist.

For the application of the latissimus dorsi muscle (LDM) to circulatory assist, the muscle is stimulated with co- or counterpulsation during the cardiac cycle. The purpose of this study was to evaluate the blood supply to the LDM and its muscular performance during each respective stimulation. The origin of the LDM was connected to a tension gauge, a potentiometer, and 1 kg of weight in series. The LDM was stimulated at a ratio of 1:1 of heart to muscle contraction for 10 min. Copulsatile stimulation made thoracodorsal arterial flow (TDF) predominant during cardiac diastole. In counterpulsatile stimulation, TDF occurred predominantly during cardiac systole. Between the 2 patterns of stimulation, no significant differences were observed in the mean TDF rate during 1 cardiac cycle. The maximal force, maximal contraction length, and power of the LDM also did not differ significantly. These results suggest that despite the difference of the TDF profile, LDM performance may be comparable between co- and counterpulsatile stimulation for the application of the LDM to circulatory assist.

Analysis of Variance↗

PubMed1997

Cryptosporidium sp. Infections in Green Turtles, Chelonia mydas, as a Potential Source of Marine Waterborne Oocysts in the Hawaiian Islands.

For the first time, Cryptosporidium sp. oocysts were identified in fecal and intestinal samples from free-ranging marine turtles, Chelonia mydas, from the Hawaiian Islands. The oocysts produced positive reactions with commercial test kits recommended for the detection of human-infectious waterborne oocysts of Cryptosporidium parvum.

Journal Article↗

PubMed1996

Detection of myocardial ischemic injury during simple cold storage by measurement of 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. Six anesthetized dogs underwent rapid cardiac extirpation and were placed in simple cold storage in saline for 12 hours. Myocardial electrical impedance was measured serially by use of a LCR meter and the changes of myocardial resistivity analyzed. Myocardial specimens were taken for myocardial ATP analysis and electron microscopic study during preservation. We investigated the correlation between myocardial resistivity and myocardial ATP content. Moreover in order to predict cardiac function after simple cold storage in saline, heterotopic cardiac transplantation in the neck was performed in mongrel dogs and left ventricular Emax (LV Emax) was measured with a micromanometer and conductance catheter method. It was then investigated whether or not it is feasible to predict cardiac function of the graft afer reperfusion from the changes in myocardial resistivity. Myocardial ATP remained above 50% of preischemic value 4 hours after preservation. Ultrastructural alterations of ischemia were observed in hearts preserved for 8 and 12 hours. In heterotopic cardiac transplantation, LV Emax at 120 minutes after reperfusion recovered to 94 +/- 13% of preischemic function in 4 hour-preserved heart, 72 +/- 10% in 8 hour-preserved heart. Percent recovery of LV Emax in the former was significantly higher than that in the latter (p<0.05). Turning points from reversible conditions to irreversible ones were between 4 and 8 hours based on myocardial ATP content, cardiac function after transplantation and morphological changes. With the time of preservation, resistivity began to increase in every dog and peaked during preservation. The time required to reach the peak point of resistivity ranged from 4 to 5.5 hours. Resistivity increase rate (RIR) decreased gradually during preservation and it was over 0.1 omega cm/min until a half-life of ATP. These results suggested that measurement of myocardial electrical impedance in the preserved heart should be feasible as an indicator of graft viability during preservation in heart transplantation.

Adenosine Triphosphate↗

PubMed1996

[A surgically treated case of ruptured true aortic arch aneurysm in association with Stanford type A chronic dissection].

A 72-year-old woman was admitted to our hospital because of hemosputum. Enhanced CT showed ruptured true aortic arch aneurysm. True aortic arch aneurysm ruptured at distal portion of aneurysm. The aorta was chronically dissected from an entry proximal to ruptured portion, to ascending aorta. Ascending aorta to aortic arch was replaced with 20 mm gelatin sealed graft under selective cerebral perfusion with hypothermia. Post-operatively tracheostomy was done because of respiratory failure, and there was some leak from distal anastomosis portion which was 42 mm in diameter at the operation. So replacement of descending thoracic aorta was performed using elephant trunk of the previously replaced graft. Post-reoperative course has been uneventful. She weaned from respiratory support. True aortic arch aneurysm combined with Stanford type A dissection is very rare. We presented ruptured true aortic arch aneurysm in association with Stanford type A chronic dissection which had an entry in true aneurysm.

Aged↗

PubMed1996

Evaluation of myocardial viability during simple cold storage with the use of electrical properties in broad frequencies.

BACKGROUND: The purpose of this study ws to determine whether myocardial viability during simple cold storage can be monitored from alteration of electrical properties of the preserved heart. METHODS: Twelve anesthetized dogs underwent rapid cardiac extirpation and were preserved in simple cold storage ( 4 degree C). They were divided into two groups according to preservation solutions. Groups S and U were preserved in saline and University of Wisconsin Solutions, respectively. The loss-tangent (Tan delta) in dielectric spectroscopy was analyzed on serial measurements of electrical properties of the preserved heart with an electrical impedance meter. Myocardial specimens were taken for myocardial adenosine triphosphate measurement with high-performance liquid chromatography and myocardial water content. We investigated the correlations among myocardial adenosine triphosphate, myocardial water content, and Tan delta. RESULTS: The maximum value of Tan delta corresponds to a frequency fT which ranged from 5 to 10 kHz in both groups and maximum Tan delta gradually decreased during preservation in both groups. Myocardial adenosine triphosphate in group U was significantly higher than that in group S. The ratio of measured adenosine triphosphate and maximum Tan delta to the preischemic values during preservation were expressed as percentage of adenosine triphosphate and percentage of maximum Tan delta. There was close correlation between myocardial percentage of adenosine triphosphate and percentage of maximum Tan delta during preservation in both groups. Myocardial water content in group S increased during preservation but did not increase in group U. There was no correlation between myocardial water content and percentage of maximum Tan delta during preservation. Tan delta function were used to characterize the electrical properties of biologic tissue and were clearly associated with ischemic histologic damage of tissues. CONCLUSIONS: Therefore measurement of electrical properties in broad frequencies of the preserved heart may be feasible as a monitor of graft viability in a minimally invasive method.

Adenosine↗

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

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↗