Search PubMed⌕ Search

Biomedical subjects

K Yasuda

Publications and source records attributed to K Yasuda.

At least 415 records · Page 23Linked to original sources
PubMed1998

The first isolation of Arthroderma benhamiae in Japan.

A clinical isolate of Trichophyton mentagrophytes from rabbit was examined by polymerase chain reaction (PCR) analysis and a mating experiment. The species-specific primers designed from the nucleotide sequences of the chitin synthase 1 (CHS1) gene in the teleomorph of Arthroderma benhamiae amplified a fragment from genomic DNA samples of A. benhamiae and the clinical isolate but not from those of A. simii and A. vanbreuseghemii. On the other hand, the species-specific primers of A. simii and A. vanbreuseghemii did not amplify any fragment from the genomic DNA of the clinical isolates. When the isolate was respectively crossed with (+) or (-) tester strains of A. benhamiae, A. simii and A. vanbreuseghemii, ascospores were produced in the crossing with the A. benhamiae (+) strain. Therefore, the isolate was identified to be A. benhamiae (-), confirming the result of molecular analysis. This is the first report on the isolation of A. benhamiae in Japan.

Animals↗
PubMed1998

Alteration of p53 clonality accompanying colorectal cancer progression.

The aim of this study was to clarify whether or not the status of gene alteration is heterogeneous in intramucosal carcinoma and homogeneous within invasive carcinoma. We selected 10 colorectal carcinoma cases (1 mucosal, 5 submucosal and 4 advanced carcinomas including 2 cases with lymph node metastasis) and analyzed the p53 gene sequence. Six colorectal cancers in this study showed heterogeneity in p53 mutations in cells from the intramucosal part. In the invasive part of a carcinoma, p53 mutation status was homogeneous intratumorally in all cases. These data indicate that, in regard to p53 gene alterations, colorectal cancers can be composed of various subclones when limited to the mucosa, but clonal selection occurs when one of these subclones commences invasion to the submucosa, generating a monoclonal invasive carcinoma.

Adenoma↗
PubMed1998

Application of the reversed elephant trunk technique during total thoracoabdominal replacement in patients with Marfan's syndrome.

The reversed elephant trunk operation has been applied in patients with extensive aortic involvement as a scheduled staged operation. We report application of the same technique in two patients with Marfan's syndrome. The two patients underwent total replacement of the thoracoabdominal aorta for a DeBakey IIIb aortic dissection. The proximal end of the prosthetic graft was invaginated to facilitate future proximal operation. No complication related to the trunk had been observed during the follow-up period.

Adult↗
PubMed1998

Pharmacokinetic differences between lansoprazole enantiomers in rats.

Because limited information is available about potential differences between the pharmacokinetics and pharmacodynamics of the enantiomers of lansoprazole, the enantioselective pharmacokinetics of the compound have been investigated in rats. There was a noticeable difference between the serum levels of the enantiomers of lansoprazole and of their metabolites, 5-hydroxylansoprazole enantiomers, after oral administration of the racemate (50 mg kg(-1)) to rats. Cmax (maximum serum concentration) and AUC (area under the serum concentration-time curve) for (+)-lansoprazole were 5-6 times greater than those for (-)-lansoprazole, whereas for (+)-5-hydroxylansoprazole both values were significantly smaller than those for the (-) enantiomer. CLtot/F values (where CLtot is total clearance and F is the fraction of the dose absorbed) for (+)-lansoprazole were significantly smaller than those for the (-) enantiomer. There was no significant difference between the absorption rate constants of the lansoprazole enantiomers in the in-situ absorption study. The in-vitro protein-binding study showed that binding of (+)-lansoprazole to rat serum proteins was significantly greater than for the (-) enantiomer. The in-vitro metabolic study showed that the mean metabolic ratio (45.9%) for (-)-lansoprazole was significantly greater than that (19.8%) for the (+) enantiomer in rat liver microsomes at 5.6 microM lansoprazole. These results show that the enantioselective disposition of lansoprazole could be a consequence of the enantioselectivity of plasma-protein binding and the hepatic metabolism of the enantiomers.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

[A case of solitary pulmonary nodule caused by Mycobacterium avium].

A 56-year-old male without respiratory symptoms, past history nor familial history, was admitted to our hospital because of pulmonary solitary nodule on the chest radiograph. Computed tomograph showed a smooth surface nodule in the left lower lobe (segment 8). Bronchofiberscopy could not give any specific histological findings nor bacteriological findings, therefore the patient underwent partial pulmonary resection by videoassisted thoracoscopic surgery. Pathology of the resected specimen revealed epithelioid cell granuloma with giant cells but not any acid-fast bacilli. He was treated with rifampicin and isoniazid for "tuberculoma". After three weeks, thirty colonies grew on an Ogawa's egg medium, which were identified as Mycobacterium avium by PCR. There are few reports about the solitary pulmonary nodule due to M. avium-intracellurale complex infection, however, it is supposed that there are many "tuberculoma's" without bacteriological differentiation between tuberculosis and nontuberculous mycobacterial infection. It is difficult to diagnose a solitary pulmonary nodule caused by nontuberculous mycobacterial infection with bronchofiberscopy, and the location of the lesion is usually subpleural, therefore it is thought that videoassisted thoracoscopic surgery is valied for the diagnosis of solitary pulmonary nodule due to nontuberculous mycobacterium.

Humans↗
PubMed1998

Micturitional disturbance in herpetic brainstem encephalitis; contribution of the pontine micturition centre.

Micturitional disturbance is rarely mentioned in human herpetic brainstem encephalitis although the pontine tegmentum, called the pontine micturition centre, seems to regulate the lower urinary tract in experimental animals. The case of a 45 year old man, who developed subacute coma and hiccup-like dysrhythmic breathing, and needed assisted ventilation is reported. Examination of CSF showed mononuclear pleocytosis and antibody against herpes simplex virus type 1, but the opening pressure was 90 cm H2O. Brain CT showed brain swelling, predominantly in the posterior fossa, and bilateral subdural effusion. Herpetic brainstem encephalitis was diagnosed, and he received 900 mg/day vidarabine. On regaining consciousness, he had left trochlear nerve palsy, left corectopia, ageusia, and urinary retention. Brain MRI showed right side dominant, bilateral pontine segmental lesions extending slightly to the midbrain and medulla. After two weeks he was able to urinate but showed nocturnal urinary frequency, urinary incontinence, and voiding difficulty. Urodynamic studies showed a residual urine volume of 350 ml and detrusor hyporeflexia on voiding. Micturitional disturbance gradually disappeared together with the neurological signs. The bilateral pontine tegmental lesions in this patient are similar to those in previous findings on brainstem strokes, evidence of the presence of a pontine micturition centre in humans.

Antibodies, Viral↗
PubMed1998

Stress induced urinary incontinence in patients with spinocerebellar degeneration.

OBJECTIVES: To examine the pathophysiology of "stress induced urinary incontinence" (urinary incontinence evoked by abdominal straining) in patients with spinocerebellar degeneration. METHODS: Micturitional symptoms of 184 patients with spinocerebellar degeneration who were admitted to hospital were studied repeatedly. Urodynamic studies were made in symptomatic patients, and consisted of uroflowmetry, measurement of residual urine, urethral pressure profilometry, medium fill water cystometry, and external sphincter EMG. RESULTS: Twenty nine (15.8%) patients with spinocerebellar degeneration showed stress induced urinary incontinence. Twenty of the 29 patients had detrusor overactivity, low compliance detrusor, or residual urine, resembling urgency and overflow types of incontinence (complicated form). The other nine had none of these findings (pure form), but showed decreased maximum urethral closure pressure in four, absence of bulbocavernosus reflex in two, absence of voluntary sphincter contraction in one, incompetent urinary storage even at the first sensation in two, and high amplitude and polyphasic neurogenic changes in three of five patients studied, indicative of neurogenic sphincter dysfunction. CONCLUSIONS: Stress induced urinary incontinence in spinocerebellar degeneration had various underlying mechanisms. Some of the patients only showed evidence of pudendal denervation, which can cause external sphincter weakness and may reflect lesions of the sacral Onuf's nucleus and the pudendal nerve. Urodynamic studies are necessary to evaluate stress induced urinary incontinence in patients with spinocerebellar degeneration, to prescribe appropriate therapies.

Adolescent↗
PubMed1998

Detrusor overactivity and penile erection in patients with lower lumbar spine lesions.

OBJECTIVES: To investigate urodynamically detrusor overactivity and evaluate surgical outcome in patients with lower lumbar spine lesions. METHODS: Eighty patients with spine lesions below the third lumbar spine including 31 patients with intervertebral disc prolapse (IDP) (mean age: 38.2 years) and 49 patients with spinal canal stenosis (SCS) (mean age: 56.7 years) were studied. Urinary symptoms and urodynamic data were recorded before and after orthopedic surgery. RESULTS: Detrusor overactivity was noted in 17 patients: 3 IDP patients (10%) and 14 SCS patients (29%). Of these 17 patients (9 males and 8 females), 14 (82%) had voiding symptoms and 15 (88%) had storage symptoms. One patient was asymptomatic. Intermittent claudication was noted in 14 patients: 8 had urgency, 11 urge incontinence and 4 male patients showed erection on walking. Of 10 patients followed up after surgery, detrusor overactivity disappeared in 5 patients, improved in 1 patient and remained unchanged in 4 patients. CONCLUSIONS: Detrusor overactivity was found in lower lumbar spine lesions. This phenomenon seemed to be caused by the irritation of sacral roots, especially on walking.

Adolescent↗
PubMed1998

Micturitional disturbance in patients with chronic inflammatory demyelinating polyneuropathy.

Eight of 32 patients (25%) with chronic inflammatory demyelinating polyneuropathy (CIDP) had micturitional disturbance, which consisted of voiding difficulty (n = 4), urgency (n = 4), or urgency incontinence (n = 1). Urodynamic studies on four symptomatic patients showed disturbed bladder sensation in two, bladder areflexia in one, and neurogenic changes of the external sphincter in one, indicative of peripheral parasympathetic and somatic nerve dysfunctions. Cystometry also showed detrusor overactivity in two patients but no evidence of CNS involvement, evidence that bladder overactivity occurs by probable pelvic nerve irritation.

Adolescent↗
PubMed1998

Studies on agents with vasodilator and beta-blocking activities. V. Synthesis and pharmacological activity of the optical isomers of TZC-5665.

Synthesis of the four optical isomers of TZC-5665 (1), a candidate for the treatment of congestive heart failure, was achieved by the reaction of chiral diaminopyridazinone (2) with chiral glycidyl ether. (3). The hypotensive and beta-blocking activities of 1 and its optical isomers were examined when given intravenously into anesthetized rats. Furthermore these compounds were evaluated for inhibitory activity on cAMP phosphodiesterase III. Among the four optical isomers, Ra,Sb-one (1c) possessed the essential activities of TZC-5665 (1).

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

A comparison of UVB-carcinogenesis between nude mice and nude beige mice.

To gain an insight into the relationship between UVB-carcinogenesis and natural killer activity, we examined ultraviolet light-induced carcinogenesis in mice with high natural killer, activity (KSN) and mice with natural killer deficiency (KSN-bg). We exposed mice six times a week to three levels of daily ultraviolet B (UVB) doses; 320, 160 and 0 J/m2/day. During the latency period of skin tumor development in KSN mice, we detected no suppression of the natural killer activity at both 320 and 160 J/m2/day. Even at 1340 J/m2/day, we could not detect any significant suppression of NK activity in KSN mice. When we irradiated spleen cells in vitro, we observed NK activity suppression. Next, we compared the carcinogenic effects of UVB-irradiation on KSN and KSN-bg mice. At 320 J/m2/day, we detected no significant differences between them. In contrast, at 160 J/m2/day, KSN-bg mice showed a significantly higher rate of skin tumor induction than KSN mice (p < 0.05). Most UVB-induced tumors were squamous cell carcinoma, the rest were spindle cell carcinoma, papilloma and mixed type. Our results suggest that NK activity plays a protective role against UVB-carcinogenesis from low daily-doses of UVB-irradiation.

Animals↗
PubMed1998

Alterations in insulin-induced postreceptor signaling in adipocytes of the Otsuka Long-Evans Tokushima fatty rat strain.

The Otsuka Long-Evans Tokushima fatty (OLETF) rat is a new spontaneous non-insulin-dependent diabetes mellitus (NIDDM) model rat strain developed in Tokushima, Japan. After 18 weeks of age, decreases of 45% and 40% respectively in insulin- and phorbol ester-stimulated [3H]2-deoxyglucose (DOG) uptake were observed, compared with those in Long-Evans Tokushima (LETO) rats (control). Insulin-specific binding and 95 kDa autophosphorylation of insulin receptor in OLETF rats were not different from those in LETO rats. Insulin-induced diacylglycerol (DG) production and Mono Q column-purified protein kinase C (PKC) translocation in adipocytes of OLETF rats were decreased compared with those of LETO rats. Insulin-induced PKC beta translocation from cytosol to membrane was also decreased in adipocytes of OLETF rats. Increases of the PKC beta I, beta II, epsilon and zeta isoforms in membranes of OLETF rats were markedly smaller than those of LETO rats. Analysis of mRNA levels of PKC isoforms in adipocytes of OLETF rats showed decreases of basal level and insulin-induced delayed responses of PKC beta I, beta II, epsilon and zeta mRNA in OLETF rats. On the other hand, insulin- or phorbol ester-induced phosphatidylinositol 3-kinase (PI 3-kinase) activation was decreased in adipocytes of OLETF rats compared with those of LETO rats. These results suggest that insulin resistance in OLETF rats, a spontaneous NIDDM model rat, may be associated with deterioration of insulin-induced DG-PKC signaling and subsequent decrease in PI 3-kinase activation.

Adipocytes↗
PubMed1998

Differential effect of the antidiabetic thiazolidinediones troglitazone and pioglitazone on human platelet aggregation mechanism.

Troglitazone and pioglitazone, antidiabetic thiazolidinediones, are known to improve insulin resistance. However, the effect of these drugs on platelet aggregation remains unclear. The chemical structure of troglitazone contains vitamin E. Accordingly, we studied the effect of troglitazone, pioglitazone, and vitamin E on thrombin-induced platelet aggregation, metabolism of phosphoinositide, protein phosphorylation, protein kinase C (PKC)-alpha and -beta, and phosphatidylinositol (PI) 3-kinase activation in vitro in human platelets. Maximum platelet aggregation by ADP, collagen, and thrombin decreased in the presence of 0.1-1 micromol/l troglitazone and 500 nmol/l vitamin E for 60 min compared with controls. However, pioglitazone did not inhibit ADP-, collagen-, or thrombin-induced platelet aggregation. Pretreatment with troglitazone and vitamin E, but not with pioglitazone, resulted in decreases in thrombin-induced phosphatidic acid production, hydrolysis of phosphatidylinositol 4,5-bisphosphate by phospholipase C, and 47-kDa protein phosphorylation. Thrombin-induced PKC-alpha and -beta activation in membrane fraction was suppressed by pretreatment with troglitazone and vitamin E, but not with pioglitazone. Separately, troglitazone and pioglitazone stimulated PI 3-kinase activity, but thrombin-induced PI 3-kinase activation was suppressed by pretreatment with troglitazone and pioglitazone for 60 min. These results suggest that troglitazone and vitamin E, but not pioglitazone, have a potent inhibitory effect on platelet aggregation via suppression of the thrombin-induced activation of phosphoinositide signaling in human platelets. Finally, the chemical structure of vitamin E may contribute to the inhibitory effect of troglitazone on platelet aggregation in human platelets.

Adenosine Diphosphate↗
PubMed1998

[Nurses' knowledge of alcohol-related problems and their treatment: a comparison of nurses in general hospital and alcoholism treatment units].

Nurses have the most contact with patients in the clinical settings, and they play an important role in the guidance and education of patients. Nurses' basic knowledge of alcohol-related problems greatly influences early discovery of and early intervention against alcohol-related problems in general units (GU). In a study undertaken mainly to understand the status of nurses' knowledge in GU, a survey was performed to compare the knowledge and attitude of nurses working in GU and those with working in units specializing in the treatment of alcoholism (AU). For reference, we used the results of separate surveys performed previously on the general population. The results showed that, compared with nurses in AU, nurses in GU (1) were more tolerant of drinking, but (2) were more stigmatic concerning alcoholism, and (3) had little knowledge concerning alcohol-related problems. Nurses in GU tended to have less knowledge about alcohol-related problems than the general population. Moreover, the knowledge of nurses in AU could not be considered sufficient. This study suggested the need for basic education concerning alcohol-related problems and their treatment aimed at nurses.

Adult↗
PubMed1998

Pharmacodynamics and pharmacokinetics of a single oral dose of nitrazepam in healthy volunteers: an interethnic comparative study between Japanese and European volunteers.

Potential interethnic differences in drug disposition and effects between Japanese and white subjects hamper the registration in Japan of medications already used in Western countries. This double-blind, placebo-controlled, crossover study was conducted to compare the pharmacodynamics and pharmacokinetics of a single oral dose of nitrazepam (5 mg) in age- and sex-matched Japanese (n = 8) and white (n = 8) healthy volunteers. The study was performed in centers in Japan and the Netherlands using the same methods and study design. Subjects were individually matched for gender, age, and body stature. Drug effects were measured by means of saccadic and smooth pursuit eye movements and visual analog lines obtained from the scales of Bond and Lader. There were no pharmacokinetic differences between the Japanese and white subjects. Clearance of nitrazepam was 0.91 +/- 0.165 mL/min/kg and 1.17 +/- 0.492 mL/min/kg, and half-life (t1/2) was 22.1 +/- 4.96 hours and 21.5 +/- 7.51 hours for the Japanese and European groups, respectively. Pharmacokinetic parameters showed no significant correlation with age, height, or weight. The average time-effect curves for the different parameters were comparable between groups. Compared with placebo, both groups showed similar significant reductions in average peak velocity and increases in saccadic inaccuracy and reaction time. Visual analog scores showed clear sedation in the white subjects, but insignificant effects in the Japanese subjects. Smooth pursuit did not change significantly in either group. Slope and intercept of the concentration-effect relationships for saccadic peak velocity showed considerable intersubject variability, but no clear differences between groups. The pharmacokinetics and pharmacodynamics of nitrazepam were similar in matched healthy Japanese and white subjects. Interethnic comparative studies are feasible, and provide meaningful information about potential racial differences in disposition and action of drugs. Such studies can form a rational basis for comparative clinical trials.

Administration, Oral↗
PubMed1998

[Partial anomalous pulmonary venous connection to the high superior vena cava: a case report of repair by modified Vargas' procedure].

A two and a half year-old boy with partial anomalous pulmonary venous connection (PAPVC) to the high superior vena cava (SVC) underwent a surgical repair by Vargas' procedure. The SVC was divided above the orifice of the anomalous pulmonary vein and the cephalad end of the SVC was anastomosed to the right atrial (RA) appendage. The anomalous pulmonary venous flow was diverted to the left atrium through the enlarged atrial septal defect using the RA wall only. Post-operative angiography showed no stenosis of pulmonary venous pathway, however, the SVC was compressed by the ascending aorta. Vargas' procedure could be useful for repair of PAPVC to the high SVC, however, care must be taken not to compress the rerouted SVC by the ascending aorta.

Child, Preschool↗