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Biomedical subjects

T Kawada

Publications and source records attributed to T Kawada.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Traumatic thoracic aortic rupture--diagnosis and surgical repair].

Fifteen cases of traumatic thoracic aortic rupture (TAR) were treated at St. Marianna University Hospital from December 1980 to July 1995. Causes of TAR were due to vehicle accidents in 14 patients and fall in one patient. On diagnosis, contrast-enhanced CT scan was routinely performed in the patients with blunt chest trauma associated with superior mediastinal widening, loss of the aortic knob or right shift of the trachea on the initial roentgenogram. When CT scan demonstrated specific signs for TAR, pseudoaneurysm formation and/or extravasation of the contrast dye, aortography was eliminated before operation. As a role, operation was performed on an emergency basis as soon as the diagnosis was confirmed. Four cases died due to intrapleural rupture before or immediately after thoracotomy. Nine (82%) of the 11 patients in whom operation was completed survived and are doing well. In one of the 4 patients who underwent operation with simple aortic cross-clamping; paraplegia developed after 30 minutes of spinal ischemia. Left heart bypass with the Bio-Pump without heparin or with an antithrombin agent, argatroban, was used in recent 6 patients. Use of left heart bypass with the Bio-Pump without anticoagulant or with argatroban appears to be promising as a safe adjunct in the repair of TAR, preventing fatal bleeding of other injured organs.

Adolescent↗
PubMed1996

[Anticoagulant therapy and obstetric management in a pregnant patient with mechanical prosthetic valve].

A 30-year-old female whose mitral valve had been replaced with a mechanical prosthetic valve 23 years ago gave birth to a healthy baby by cesarian section under controlled anticoagulant therapy. Warfarin was replaced with intravenous heparin just one week before cesarian section and heparin administration was stopped several hours prior to the operation which was successfully carried out without excessive blood loss. Although warfarin carries a risk of teratogenecity, fortunately, the baby had not any somatic malformation. We believe that pregnancy is not contraindicated in patients with mechanical prosthetic heart valves, however, a strict observation of the cardiac function during middle and late trimesters of gestation by echocardiography and planned anticoagulant therapy are necessary in order to prevent maternal congestive heart failure and thromboembolism and protect a neonate against intracranial hemorrhage.

Adult↗
PubMed1996

[Emergency myectomy in a patient with hypertrophic obstructive cardiomyopathy complicated with left heart failure and cardiac arrest].

Major cause of death in HOCM is sudden death due to ventricular arrhythmias, and only 10% of the death is caused by congestive heart failure. We report a 38-year-old woman of HOCM complicated with lung edema and cardiac arrest due to acute left heart failure. Intraventricular pressure gradient showed 125 mmHg in previous study, and echocardiogram demonstrated evidences suggestive of terminal-staged HOCM. After unsuccessful attempts of intravenous propranolol administration, emergency myectomy of left ventricular outflow tract was carried out. Postoperative course was uneventful, and intraventricular pressure gradient was relieved. The patient is now asymptomatic without medication after 1 years of operation. This case suggests that emergency myectomy may be a choice to relieve refractory congestive heart failure in patient with HOCM.

Adult↗
PubMed1996

[Prognostic factors of nasopharyngeal carcinoma treated by radiotherapy].

This study was a retrospective analysis of 82 patients with histologically confirmed nasopharyngeal carcinoma, who were treated at Keio University Hospital from March 1983 to March 1993. We studied all cases(62% of them were stage IV) with regard to their prognostic factors and chronic side effects induced by radiation. All patients were received extended-field radiotherapy from the base of the skull to the supraclavicular lymph node area. The five- and ten-year overall survival rates for the entire group were 59% and 49%, respectively. Three stage I patients were alive without recurrence or metastases for more than 5 years. The ten-year survival rate stage II-III for patients (23 patients) was 78%, and for stage IV (56 patients) 37%. The five-year survival rate of patients in T2-3 group without lymph node metastasis was 88%, while it was reduced to 55% for patients with metastasis. The prognosis of T4 patients was very poor: their five-year survival rate was 37% with lymph node metastasis, and 35%, without lymph node metastasis. Patients under 46 years old showed an increased survival rate compared with patients over 46 years old. Patients who completed less than 52 days of radiation therapy found to have a better prognosis than those receiving radiation for a longer period. Our multivariate analysis indicated that age, radiation period and N-factor were statistically significant in influencing prognosis. Hearing loss occurred relatively high with 20% of cumulative incidence in our study, probably because they received radiation therapy with the extended field including bilateral middle and inner ear. Extended-field radiotherapy for patients with nasopharyngeal carcinoma might contribute to improving their cure-rate, and precise radiation planning is warranted to avoid the late complications such as hearing loss.

Adenocarcinoma↗
PubMed1995

Augmented expression of the obese gene in the adipose tissue from rats fed high-fat diet.

Expression of the obese (ob) gene is augmented in the adipose tissue in several rodent models of genetic obesity. In the present study, we examined the ob gene expression in a rodent model of acquired obesity obtained by pure overfeeding of normal rats. Male Sprague-Dawley rats at 8 weeks of age were fed standard diet or high-fat diet. Rats fed high-fat diet developed moderate degree of obesity, hyperglycemia, and hyperlipidemia as compared with rats fed standard diet. Northern blot analysis revealed that the ob gene is expressed abundantly in the adipose tissue obtained from the epididymal, mesenteric, subcutaneous, retroperitoneal, and interscapular fat pads in rats fed standard diet. Expression of the ob gene was augmented in all the adipose tissue examined in rats fed high-fat diet. The present study demonstrates that the ob gene expression is augmented in the adipose tissue in diet-induced obesity, thereby suggesting the pathophysiologic roles of the ob gene in acquired obesity.

Adipose Tissue↗
PubMed1995

Cloning and sequencing of the gene encoding the mouse vitamin D receptor.

The mouse vitamin D receptor (VDR)-encoding cDNA was cloned and the coding regions were sequenced. Comparison of the amino-acid sequence to that of humans and rats revealed high homology in the DNA- and ligand-binding domains. Divergence appeared in the internal region between the two domains.

Amino Acid Sequence↗
PubMed1995

Contribution of activation of K+ channels to glyceryl trinitrate-induced relaxation of rabbit aorta.

1. Possible contribution of K+ channel opening to the relaxation by glyceryl trinitrate (GTN) was examined using isolated rabbit aorta. 2. While glibenclamide and apamin failed to affect relaxation by GTN, both charybdotoxin (ChTx) and iberiotoxin (IbTx) effectively attenuated GTN-induced relaxation. 3. The increase in cGMP produced by GTN was not attenuated by ChTx and IbTx. 4. The inhibitory effect of ChTx on GTN-induced relaxation was not reduced in the presence of zaprinast, indicating that cGMP but not GMP was responsible for activation of the K+ channel. 5. Okadaic acid, a selective inhibitor of protein phosphatase 2A, had no effect on the relaxation by GTN. These results indicate that, though small in degree, activation of a ChTx-sensitive K+ channel (large conductance Ca(2+)-activated K+ channel) is involved in the GTN-induced relaxation in rabbit aorta.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1995

Use of dextran-primed extracorporeal circuit in the canine model for venous return: with special references to the effects of two dihydropyridine-type Ca2+ channel blockers.

1. A successful canine "venous return (VR)" model is described, in which all hemodynamic parameters were stable for about an hour, by minimizing extracorporeal circuit primed with dextran (DX) so that the dilution of the blood was kept about 33%. 2. Increases in VR by norepinephrine (1 micrograms/kg) and dose-dependent decreases in VR by glyceryl trinitrate (1-30 micrograms/kg) were clearly observed. 3. While 1 microgram/kg of nifedipine produced a small, but significant decrease in VR, only a tendency for decrease was observed with higher doses which produced a definite fall in blood pressure. 4. Nisoldipine (1 microgram/kg) caused a small decrease in VR. However, higher doses that produced a large and persistent hypotension produced an increase in VR due probably to intense reflex translocation of the blood. The increase in VR was reversed with carvedilol, a beta-blocker with alpha-blocking activity.

Animals↗
PubMed1995

Swimming endurance capacity of mice is increased by chronic consumption of medium-chain triglycerides.

The effect of chronic administration of medium-chain triglycerides (MCT) on swimming endurance (swim capacity) was investigated in male Std ddY mice. The mice were fed a diet containing 80 g MCT + 20 g long-chain triglycerides (LCT)/kg diet for 6 wk; mice fed diet containing 100 g LCT/kg diet were used as controls. After being accustomed to swimming, the mice were subjected to forced swimming every 2 d in the current water pool that we had developed, and the total swimming period until exhaustion was measured. The total swimming period was used as the index of swim capacity. The group fed MCT showed significantly greater swim capacity than the control group (89.5 +/- 2.5 vs. 80.2 +/- 2.0 min). In another experiment, after 4 wk of MCT diet consumption, significantly greater swim capacity was found in untrained mice. The major metabolic consequences of the adaptations of muscle to prolonged MCT administration during endurance training were higher activities of 3-oxo acid CoA-transferase (P < 0.01), citrate synthase (P < 0.1) and malate dehydrogenase (P < 0.1). These findings suggest that increases in the enzyme activities of the tricarboxylic acid cycle and ketone body utilization associated with the chronic administration of an MCT-containing diet enhance swim capacity in mice.

Animals↗
PubMed1995

Chronic administration of beta-adrenergic agonists can mimic the stimulative effect of cold exposure on protein synthesis in rat brown adipose tissue.

When mammals are exposed to a cold environment for a long time, the capacity of nonshivering thermogenesis by brown adipose tissue (BAT) increases in association with the stimulation of synthesis of some specific proteins and tissue hyperplasia, which are totally dependent on sympathetic innervation to this tissue. To clarify the roles of the adrenergic mechanisms for the cold-induced protein synthesis and hyperplasia in BAT, in this study, the effects of chronic treatment with adrenergic agonists using an osmotic mini-pump were examined in rats. Continuous administration of noradrenaline or isoproterenol (beta-agonist) for 10 days resulted in increased synthesis of the mitochondrial uncoupling protein and an isoform of glucose transporter (GLUT4), and tissue hyperplasia, in the same way as after cold exposure of the same duration. Phenylephrine (alpha-agonist) administration did not have any significant effect. Surgical sympathetic denervation completely abolished the effects of cold exposure, whereas it did not influence those of adrenergic agonists at all. These results indicate that the stimulative effects of cold exposure on protein synthesis and hyperplasia of BAT are attributable solely to the beta-adrenergic action of noradrenaline secreted from the sympathetic nerves in this tissue.

Adipose Tissue, Brown↗
PubMed1995

Explorations into development of a neurally regulated cardiac pacemaker.

Although the artificial cardiac pacemaker has contributed to the management of patients with serious arrhythmias, its rate-responsive function is not sufficient to provide physiological regulation of heart rate (HR). To achieve truly physiological rate response in any given patient, we propose a framework to develop a pacemaker directly regulated by sympathetic nerve activity (SNA). In eight anesthetized rabbits, we quantified the dynamic transduction characteristics from SNA to HR as a transfer function. We then characterized the decoding rule as an impulse response, that is the transfer characteristics in the time domain. The transfer function was approximated by a first-order, low-pass filter with lag time (corner frequency: 0.024 +/- 0.013 Hz, lag time: 0.98 +/- 0.09 s). Predicted HR correlated well with measured HR (r = 0.80-0.98). The standard error of the prediction relative to mean HR was only 1.2 +/- 0.7%, indicating that the prediction was reasonably accurate. Direct decoding of SNA to predict instantaneous HR is possible through this analysis. This framework should enable development of a neurally regulated artificial pacemaker.

Animals↗
PubMed1995

Effects of cadmium and lead exposure on urinary N-acetyl-beta-D-glucosaminidase, beta 2-microglobulin and metallothionein of workers.

Cadmium (Cd), lead (Pb), N-acetyl-beta-D-glucosaminidase (NAG), beta 2-microglobulin (BMG), metallothionein (MT) and creatinine (cre) in urine were measured in 36 male workers. Urinary Cd and Pb ranged from 0.2 to 9.7 and 0.1 to 4.8 micrograms/g cre with geometric means of 1.17 and 1.27 micrograms/g cre, respectively. Partial correlation coefficients between the logarithm of urinary Cd and that of NAG, BMG or MT controlling for pH and age were 0.460 (p < 0.01), 0.095 and 0.677 (p < 0.01), respectively. Partial correlation coefficients between the logarithm of Pb and that of NAG, BMG or MT controlling for pH and age were 0.040, 0.403 (p < 0.05) and -0.183, respectively. Multiple regression analysis was conducted on urinary NAG, BMG and MT using age, pH, log U-Cd and U-Pb. Log U-Cd was the only significant predictor variable of NAG (beta = 0.572; p < 0.01). Log U-Pb was the only predictor variable of BMG (beta = 0.386, p < 0.01). pH (beta = 0.286, p < 0.05) and Log U-Cd (beta = 0.839, p < 0.05) were significant predictor variables of MT.

Acetylglucosaminidase↗
PubMed1995

Effects of traffic noise on sleep: a review.

Examination of the effect of noise on sleep indicated the following: 1) Views differ on habituation to noise. 2) REM sleep in all-night sleep decreases with exposure to noise. The probability of transient changes of REM sleep to other stages is low. REM sleep induction may be disturbed by noise exposure, but once it has been induced, changes to other stages or waking occur only to a small extent. 3) A transient decrease in sleep spindles is caused by noise exposure, but the number of sleep spindles for all-night sleep increases. Sleep disturbance by noise is compensated for by an increase in sleep spindles during periods of silence, possibly indicating sleep maintenance. 4) Under certain circumstances, subjective sleep is a better indicator of the effects of noise on sleep than objective sleep parameters determined by sleep polygraphy. 5) There is a linear dose-response relationship between the peak noise level and the rate of stage shift or waking. The threshold of the noise effect is about 40 dBA.

Humans↗
PubMed1995

Decreased immunoreactive inhibin and increased FSH levels in cryptorchidism after orchidopexy.

The blood FSH level is often high in patients with severe testicular disorders including cryptorchids. To examine whether inhibin is involved in the increase in FSH we measured immunoreactive inhibin, FSH, LH, and testosterone in 17 patients after orchidopexy. FSH was extremely high (20 mIU/ml or above) in 3 patients. The inhibin level was significantly lower (P < 0.01) in these 3 patients (6.47 +/- 2.19 IU/ml; mean +/- SEM) than in the other 14 patients (14.31 +/- 3.96 IU/ml). All 3 high-FSH patients had azoospermia. Testosterone and LH were normal in one of them. Even considering problems involved in the inhibin assay, the high FSH levels are considered to reflect reductions in the blood inhibin level due to Sertoli cell dysfunction. These findings suggest that inhibin plays an important role in the suppression of FSH at least in some patients after orchidopexy.

Adolescent↗
PubMed1995

Indicators of renal effects of exposure to cadmium: N-acetyl-beta-D-glucosaminidase and others.

The renal effects of cadmium (Cd) have been studied in industrial workers exposed to Cd and inhabitants of Cd-polluted districts, as the kidney is a critical organ in exposure to Cd. Several biological indicators of Cd have been proposed including N-acetyl-beta-D-glucosaminidase (NAG) and beta 2-microglobulin (BMG) in urine for the detection of early renal effects. The average concentrations of Cd in urine samples were over 10 micrograms/g.creatinine in classic researches. Even in the industrial field, this exposure level is now hardly observed in Japan and western countries. The situation is the same with inhabitants in general living in a Cd-polluted district. From the viewpoint of consistency of the association, the relationship between Cd and NAG has become fairly definite. Stability in the pH change, simplicity, low cost and the reliability of measurements were also satisfactory. NAG is one of the recommended tools for detecting minimum renal effects under 10 micrograms/g.creatinine of Cd.

Acetylglucosaminidase↗
PubMed1995

The relationship between being satisfied with one's health, good health practices and personal symptoms of ill health.

The focus of this study was satisfaction with health and its relationship to good health practices, symptoms and current use of medication. A self-administered questionnaire was circulated to employees of a railroad company. 3,639 males aged 18 to 54 (41.4 +/- 7.61) were selected. Seven good health practices each scored 1 were not smoking including quitting, not drinking or drinking less than six days a week, exercise more than two days per week, body mass index (BMI) being 20 to 28, total nightly sleeping time between six and nine hours, having breakfast everyday, and not eating between meals. Each score was summed up as health practice index (HPI). We also asked about health satisfaction for the past year, subjective symptoms over the last two to three months, and present medication history. HPI increased significantly in the group aged 45 to 54, this group being satisfied with their health. A decrease in the percentage of eating between meals in the under 35 group, inappropriate BMI in the 45 to 54 group, and regular exercise in the group aged 50 or older was recognized. Health satisfaction was predicted using symptoms, present medication, age and health practice. Standardized discriminant coefficients of symptoms and present medication were 0.672 and 0.610, and they were more associated to health satisfaction than health practice.

Adolescent↗