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Biomedical subjects

N Yoshimura

Publications and source records attributed to N Yoshimura.

At least 307 records · Page 17Linked to original sources
PubMed1996

[Myocardial ischemia induced by air bubbles].

Intraoperative transesophagial echocardiography (TEE) was performed in a 27-year-old man who underwent direct suture for atrial septal defect (ASD) under general anesthesia. Myocardial ischemia occurred about five minutes after weaning from cardiopulmonary bypass, and at that time TEE showed that anteroseptal wall, lateral septal wall and lateral wall are severely hypokinetic and another wall is diffusely hypokinetic in the left ventricle after detecting air bubbles in the left ventricle by TEE. The changes in TEE preceded the ST elevation in the ECG. Bolus infusion of isosorbide dinitrate and continuous infusion of nitroglycerin showed no effects on these changes. Ten minutes after the onset of myocardial ischemia, these changes were alleviated. TEE enabled us to detect air bubbles and evaluates myocardial ischemia before the appearance of ST changes in ECG.

Adult↗
PubMed1996

[A population based study on factors related to bone mineral density in Wakayama Prefecture].

For evaluation of the community health program, 1543 inhabitants aged 40-79 years were recruited as cohort members in Miyama Village, Wakayama Prefecture. In this cohort, bone mineral density (BMD) of 400 subjects, 50 males and 50 females each randomly selected from each of four age strata, was measured at the lumbar spine and femur neck by dual energy X-ray absorptiometry. Information on exposure to possible risk factors was obtained from a self-administered questionnaire. The results were as follows; BMD at the lumbar spine and femur neck in women aged 70-79 who maintained an exercise habit (> or = one hour/week) was significantly higher than women with no exercise habit. The BMD at the femur neck in men aged 60-79 with alcohol drinking habit was significantly higher than those with no drinking habit. Significant correlation was not seen between milk intake or smoking and the BMD. BMD at the femur neck in women aged 60-69 with multiple child births (> or = 4) were significantly higher than those with fewer child births. The BMD in women aged 50-59 with earlier onset of menarche was higher than those with late menarche. Significant reduction in BMD of postmenopausal women was observed compared to premenopausal women analyzed after matching for age. The result of analysis of quantification method of the first type showed that age and menopause had a marked effect on BMD. Concerning lifestyles as other factors, a positive correlation was observed between BMD and drinking for men and exercise for women. These factors appear to be useful indicators of risk for osteoporosis.

Adult↗
PubMed1996

[Enzyme saturation of sevoflurane in piglets at clinically-used concentrations].

To investigate if sevoflurane saturates the metabolic capacity of the enzymes responsible for sevoflurane at clinically-used concentration ranges, we compared plasma fluoride levels and urinary excretion of inorganic fluoride in piglets after (1) low concentration sevoflurane anesthesia versus (2) high concentration sevoflurane anesthesia. Eleven male piglets, weighing 18-23.5 kg, were randomly divided into two groups: 1) L group: five animals were anesthetized for two hours with sevoflurane at 0.8% end-tidal concentration (0.4 MAC); 2) H group: six animals were anesthetized for two hours with sevoflurane at 3.0% end-tidal concentration (1.4 MAC). Plasma inorganic fluoride levels, blood sevoflurane concentration, urinary inorganic fluoride concentration and urine volume were measured. The blood sevoflurance concentration in both groups reached their plateau levels 30 min after the start of anesthesia. The plateau levels in the H and L groups were 275-306 microM and 105-115 microM, respectively. The plasma fluoride concentrations reached plateau levels 60 min after the start of anesthesia in both groups. The H group showed significantly higher plasma fluoride levels than the L group during sevoflurane anesthesia. The H group also showed significantly higher urinary excretion of inorganic fluoride than the L group. Therefore, metabolite production levels in the H group were significantly higher than the L group. These results suggest that low concentration sevoflurane anesthesia did not saturate the metabolic capacity of the enzymes responsible for defluorination of sevoflurane in piglets.

Anesthetics, Inhalation↗
PubMed1996

Event-related potentials during paired associate memory paradigm.

We have studied event-related potentials (ERPs) during a visual paired association task with delayed discrimination in 10 normal right-handed subjects. After subjects completely memorized 4 pairs of figures during a learning period, they were presented with each cue (S1) and asked to judge whether the following figure (S2) formed one of the memorized pairs or not. A choice reaction task with delay was used for control in an attempt to identify brain activity specifically related to memory function. ERPs were recorded from 21 scalp electrodes and those occurring between the S1 and S2 presentation were analyzed. Two ERP components associated with memory function were identified in the difference waveform between the responses in the paired association task and those in the choice reaction task. One was a posterior positive component which appeared between 390 ms and 1100 ms after the S1 presentation and the other was a sustained frontal negative component which began at about 1100 ms after S1 and ended just before the S2 presentation. Both potentials were distributed predominantly on the scalp overlying the left hemisphere. It is postulated that the early posterior positive component may reflect retrieval of information from association memory, whereas the late frontal negativity may reflect retention of information in working memory.

Adult↗
PubMed1996

[A case report of closing aortic dissection with cardiac tamponade].

A 64-year-old man was hospitalized with severe chest and back pain. A computed tomography (CT) demonstrated an acute type A aortic dissection with cardiac tamponade. Emergency pericardial drainage was performed. Then he was referred to our hospital. An enhanced CT showed an acute type A aortic dissection with thrombosed false lumen. A digital subtraction angiography (DSA) showed no intimal tear and false lumen. He received the medical treatment. Marked elevation of fibrinogen, thrombin-antithrombin III complex (TAT), plasmin-alpha(2) plasmin inhibitor complex (PIC), fibrin degradation products (FDP), and D-Dimer indicated the activation of both coagulation and fibrinolysis in the false lumen. These thrombotic and fibrinolytic parameters were completely normalized 6 weeks after admission. He was discharged in good health 7 weeks after admission.

Aortic Dissection↗
PubMed1996

[A comparison of various ways of cardiac output measurement by thermodilution methods].

We compared cardiac output values obtained by the following 3 methods: 1. Iced bolus injectate method, using the injectate temperature actually measured for computation [bolus cardiac output with flow-through temperature probe: BCO (p)]. 2. Continuous cardiac output measurement, using Vigilance system (continuous cardiac output: CCO). 3. Iced bolus injectate method, assuming injectate temperature to be 0 degrees C (bolus cardiac output without flow-through temperature probe: BCO). Only the subject receiving cardiovascular surgeries using cardiopulmonary bypass (CPB), and requiring a thermodilution catheter for hemodynamic monitoring during anesthesia were selected for the study. The total cases consisted of 15 patients (10 males), in which 60 measurement were made. Following the anesthetic induction with fentanyl, midazolam, vecuronium bromide, and intubation, a Baxter Swan-Ganz CCO thermodilution catheter was inserted through the right internal jugular vein. Compared to BCO(p), CCO showed excellent precision and bias; (r2 = 0.935, P < 0.0001, bias = -0.19 l.min-1, SD = 0.36 l.min-1). Although BCO correlated well with BCO(p), the bias was much greater (r2 = 0.919, P < 0.0001, bias = -1.25 l.min-1, SD = 0.45 l.min-1) than BCO(p). In conclusion, the values obtained by BCO(p) and CCO methods were very accurate. On the other hand, a considerable overestimation was found with BCO since the compensation for actual injectate temperature was not performed

Cardiac Output↗
PubMed1996

[Anesthesia for a patient with pheochromocytoma associated with chronic renal failure].

A case of a 53-year-old man with left pheochromocytoma associated with chronic renal failure is described. He had been on regular hemodialysis for 15 years. Also, because of right renal carcinoma, he underwent right nephrectomy at the same time. For preoperative preparation, we kept the patient's dry weight. Anesthesia was induced with isoflurane 1.0% in oxygen, and fentanyl 0.3 mg and midazolam 5 mg, followed by tracheal intubation facilitated with vecuronium. Anesthesia was maintained with isoflurane 0.5% in oxygen 50-100%, fentanyl and midazolam. Intraoperative hypertension during the manipulation of the tumor and hypotension after removal of the tumor were controlled by continuous or bolus infusion of phentolamine and norepinephrine respectively. For intraoperative fluid management, we administered crystalloid solution 4 ml.kg-1.hr-1. Careful preoperative management was carried out to prevent severe intraoperative and postoperative cardiovascular or respiratory complications.

Adrenal Gland Neoplasms↗
PubMed1996

Ocular hypotensive mechanism of intravitreally injected brain natriuretic peptide in rabbit.

PURPOSE: To determine whether brain natriuretic peptide (BNP) affects intraocular pressure (IOP), aqueous humor dynamics, and cyclic guanosine monophosphate (cGMP) concentration in the aqueous humor of the rabbit eye. METHODS: Twenty microliters of 10(-4) M and 10(-5) M (2 nmol, 0.2 nmol) BNP or atrial natriuretic peptide (ANP) were injected intravitreally into rabbit eyes, after which the IOP was measured using a pneumatonometer. Aqueous humor dynamics were studied at approximately 6 hours after the intravitreal injection of 2 nmol BNP. Aqueous humor flow was measured by fluorophotometry, and outflow facility was measured by the two-level constant pressure perfusion method, whereas uveoscleral outflow was measured by the fluorescein isothiocyanate-dextran perfusion method. The concentration of cGMP in the aqueous humor at 6 hours after injection of 2 or 0.2 nmol BNP also was measured by enzyme immunoassay. RESULTS: Intravitreal administration of BNP or of ANP caused a decrease in IOP, with a maximum effect at approximately 6 hours after the injection. Total outflow facility in eyes treated with 2 nmol BNP increased by 29%, although the aqueous humor flow and uveoscleral outflow did not show significant changes. The concentration of cGMP in the aqueous humor increased significantly in BNP-treated eyes. CONCLUSIONS: Intravitreal injection of BNP into rabbit eyes reduced IOP because of an increase in the outflow facility. Brain natriuretic peptide also increased the concentration of cGMP in the aqueous humor. It is probable that BNP-activated guanylate cyclase induced an upregulation of cGMP in the aqueous humor.

Animals↗
PubMed1996

Mainz pouch with appendix-umbilical stoma using catheterizable conduit elongated with continuous cecal segment: a case report.

The Mainz pouch with appendix-umbilical stoma is a very stable method for continent, self-catheterizable urinary reservoir in the presence of a healthy appendix. If the appendix is too short or an unexpected stenosis is seen at its distal portion, the elongation of the conduit using a part of the cecum and the implantation of the conduit to the pouch by the Mitrofanoff method can be a good alternative procedure. We herein report our experience in a 53-year-old male with high grade, invasive bladder tumor, who underwent cystourethrectomy and appendix Mainz pouch operation using the above technique.

Appendix↗
PubMed1996

Directly visualized cerebral circulation during retrograde cerebral perfusion.

BACKGROUND: Retrograde cerebral perfusion (RCP) was clinically introduced as a supportive technique to protect the brain during operations on the thoracic aorta. However, it remains unclear whether this procedure provides adequate blood supply for the brain. METHODS: We have observed the optic fundus of patients undergoing operation on the thoracic aorta to evaluate the cerebral circulation during RCP. There were 1 male and 3 female patients, ages ranged from 34 to 78 years. RCP time ranged from 39 to 70 minutes, and blood flow via the superior vena cava cannula ranged from 200 to 400 ml/min. RESULTS: The arteries of the retina showed marked constrictions soon after the initiation of RCP. The veins showed almost normal diameter. The large arteries were reduced to thin threads, while the smaller arteries were invisible at 30 minutes after the initiation of retrograde cerebral perfusion. CONCLUSION: Ophthalmoscopic findings demonstrate the reduction of cerebral blood flow, especially in arteries, during RCP. Although RCP is a useful technique for cerebral protection, it could be mentioned that the blood supply to the brain by RCP is not enough to maintain good cerebral metabolism.

Adult↗
PubMed1996

A simple technique for the prevention of lower limb ischemia during femoral veno-arterial cardiopulmonary support.

OBJECTIVE: We describe a simple technique to prevent the lower limb ischemia during femoral veno-arterial cardiopulmonary support (CPS). PATIENTS: Between July 1994 and September 1995, five patients underwent the insertion of femoral veno-arterial CPS with distal limb perfusion for the treatment of circulatory collapse after cardiac surgery. METHODS: After CPS is established, the ipsilateral superficial femoral artery (SFA) is punctured downward with a 14-gauge Teflon catheter and connected to the side port of the membrane oxygenator. RESULTS: None of the patients were complicated by lower limb ischemia for up to 77 hrs on CPS with distal limb perfusion. CONCLUSIONS: Active perfusion through a 14-gauge Teflon catheter downstream to the ipsilateral SFA is effective in preventing lower limb ischemia during prolonged femoral veno-arterial CPS after cardiac surgery.

Adult↗
PubMed1996

[Relation between defect in comprehension and frontal lobe lesion].

We assessed anatomical findings and language defects in 14 right handed patients who had fluent aphasia following left frontal lobe lesion. From the onset of aphasia all of the patients showed fluent speech and excellent repetition but difficulty in word finding and impairment in language comprehension. We administered to all of the patients the Western Aphasia Battery, a 50-item pointing task using line drawings representing single words selected from among common Japanese words for language training for aphasics, and the Token Test. Anatomical analysis was performed using brain CT and/or MRI. The patients were divided into three groups on the basis of the extent of impairment in comprehension of single words: one group showed no impairment, another showed slight impairment and the other showed severe impairment. The lesion site differed among the groups. Each group had a different lesion site. We concluded the following: first, lesions in Brodmann's areas 6 and 9 produce impairment in comprehension of single words, with lesions extending to anterior to Broca's area producing more impairment than those without the extending lesions. Second, lesions in the frontal lobe produce impairment in comprehension of complex sentences.

Adult↗
PubMed1995

[Effects of allopurinol on renal damage following renal ischemia].

We investigated the effects of allopurinol on renal damage following renal ischemia. Male Wistar rats weighing 250-300 g were classified into enflurane and allopurinol groups and anesthetized for 5 minutes using 1.7 MAC of enflurane in 30% oxygen. Then the left renal artery was dissected and clamped. Arterial occlusion was performed under 1.3 MAC enflurane for 30 minutes. Anesthesia was maintained for an additional 90 minutes after releasing the clip. In the allopurinol group, the rats were administered with allopurinol 3 mg.kg-1 intravenously prior to renal ischemia. At the end of anesthesia and 24 hours after the discontinuation of anesthesia, the necrotic areas, kidney weight/body weight ratios, gamma-GTP and NAG activities of the kidney which had been clamped were examined. Urinary gamma-GTP and NAG activities and serum inorganic fluoride concentrations were also measured. The necrotic area was significantly smaller in the allopurinol group than in the enflurane group. The activity of gamma-GTP in the kidney was higher in the allopurinol group than in the enflurane group. The kidney weight/body weight ratio was lower in the allopurinol group than in the enflurane group. There was no difference in serum inorganic fluoride concentration between the allopurinol and enflurane groups. These results suggest that allopurinol decreases renal damage following renal ischemia under enflurane anesthesia.

Allopurinol↗
PubMed1995

[Anesthetic management of cesarean section in a patient with dilated cardiomyopathy].

We report the anesthetic management of Cesarean section in a pregnant (31 weeks) woman with dilated cardiomyopathy. She had dyspnea and chest pain which were signs of congestive heart failure. The left ventricular ejection fraction was 38%. Anesthesia was induced and maintained with fentanyl, midazolam and vecuronium. There was no significant cardiovascular changes in the mother during the operation. The baby was apneic and showed no movement at birth, but he was immediately intubated and his condition became almost normal on the following day. In the anesthesiological management of Cesarean sections with cardiac disease, general anesthesia with fentanyl can be used to minimize cardiovascular changes in the mother as long as the baby is immediately resuscitated after delivery.

Adult↗
PubMed1995

Acute left atrial thrombus causing cardiogenic shock following mitral valve replacement: report of a case.

We report herein the rare case of a 53-year-old woman who developed cardiogenic shock due to an acute left atrial thrombus following replacement of the mitral valve. A definitive diagnosis was not able to be made using precordial echocardiography because of the broad, flat shape of the thrombus; however, transesophageal echocardiography imaged the thrombus in detail. The patient was initially stabilized by percutaneous cardiopulmonary support after which a thrombectomy was successfully performed.

Echocardiography, Transesophageal↗
PubMed1995

Critical re-examination of the distribution of aromatase-immunoreactive cells in the quail forebrain using antibodies raised against human placental aromatase and against the recombinant quail, mouse or human enzyme.

Mouse and quail aromatase cDNAs were isolated from libraries of mouse ovary and quail brain by using a human aromatase cDNA fragment (hA-24) as a probe. These three cDNAs were inserted into plasmid vectors and expressed in Escherichia coli. Antisera against these purified recombinant proteins were raised in rabbit and purified by ammonium sulfate fractionation and affinity chromatography. The three antibodies directed against recombinant human, mouse and quail proteins were used to visualize aromatase-immunoreactive cells in the quail brain. They were compared with the antibody raised against human placental aromatase used in previous experiments and with another antibody recently developed by similar methods. The signal obtained with all antibodies was completely abolished by preadsorption with the homologous recombinant antigens and the signal produced by the two antibodies raised against placental aromatase was similarly abolished by a preadsorption with recombinant quail aromatase. The antibodies raised against recombinant proteins identified the major groups of aromatase cells previously described in the quail brain. The antibodies directed against the mouse and quail antigen identified more positive cells and stained them more densely than the antibodies raised against human recombinant antigen or purified placental aromatase. The new cell groups identified by the antibody raised against quail recombinant aromatase were located in an area ventral to the fasciculus prosencephali lateralis, the nucleus accumbens, the paleostriatum ventrale, the nucleus taeniae, the area around the nucleus ovoidalis, the caudal tuber and the mesencephalic central gray. A critical re-examination of the distribution and nomenclature of the aromatase-positive cells is proposed based on these new findings.

Animals↗
PubMed1995

Pharmacologic intervention for ischemic brain edema after retrograde cerebral perfusion.

Retrograde cerebral perfusion has recently been the focus of interest as a simple new technique of brain protection during aortic arch operations. We undertook the experimental protocol of 120 minutes of retrograde cerebral perfusion followed by antegrade reperfusion. Eighteen mongrel dogs were used. Retrograde cerebral perfusion was maintained at a flow rate of 150 to 250 ml/min to keep the perfusion pressure from 15 to 25 mm Hg. Animals were divided into three groups as follows: in group I, no treatment was received during and after retrograde cerebral perfusion; in group II, mannitol (2 gm/kg) was administered before cardiopulmonary bypass was restarted; and in group III, antivasospastic substance (1,2-bis nicotinamido]-propane) was continuously injected during and after retrograde cerebral perfusion (1 mg/kg per minute). Cerebral blood flow decreased during retrograde cerebral perfusion in all three groups. Cerebrovascular resistance showed marked increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with the values in groups II and III (group I: 3.35 +/- 0.73 and 5.00 +/- 1.57 mm Hg/ml per 100 gm per minute; group II: 1.30 +/- 0.33 and 1.03 +/- 0.17 mm Hg/ml per 100 gm per minute; group III: 1.24 +/- 0.41 and 0.98 +/- 0.24 mm Hg/ml per 100 gm per minute). The oxygen extraction level was reduced by cooling, but it rose to a higher level as a result of significant desaturation of returned blood even in deep hypothermia during retrograde cerebral perfusion. Both cerebral metabolic rate of oxygen and cerebral metabolic rate of glucose remained at low levels during retrograde cerebral perfusion. Ratios of cerebral blood flow to cerebral metabolic rate of oxygen and cerebral blood flow to cerebral metabolic rate of glucose were markedly reduced during retrograde cerebral perfusion. Intracranial pressure showed significant increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with values in group II or group III (group I: 22.7 +/- 2.8 and 20.6 +/- 5.1 mm Hg; group II: 6.3 +/- 1.8 and 5.3 +/- 1.3 mm Hg; group III: 4.2 +/- 1.7 and 7.7 +/- 2.8 mm Hg). Water content of the brain tissue in group I (77.54% +/- 0.29%) was significantly higher than that in group II (74.71% +/- 0.76%) or group III (74.14% +/- 0.48%). These data suggest that the supply of oxygen or glucose by retrograde cerebral perfusion is not enough to maintain sufficient cerebral metabolism, which may cause brain edema during antegrade reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗