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Biomedical subjects

T Sumiyoshi

Publications and source records attributed to T Sumiyoshi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Changes in limbic dopamine metabolism following quinolinic acid lesions of the left entorhinal cortex in rats.

To examine the effects of lesions of the entorhinal cortex on limbic dopamine (DA) metabolism, DA and its metabolites were assayed in five brain regions (the medial prefrontal cortex, anterior cingulate cortex, caudate-putamen, accumbens nucleus, and lateral amygdala), 14 and 28 days after quinolinic acid or sham lesions of the left entorhinal cortex in rats. Concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) on day 14 in the medial prefrontal cortex, accumbens nucleus, and lateral amygdala of the entorhinal cortex lesioned animals were significantly decreased compared with the controls, but they returned to control levels on day 28. The concentration of DA in the lateral amygdala and spontaneous locomotion to a novel environment were significantly increased on day 28 after the lesion. These results suggest that entorhinal cortex lesions alter mesolimbic dopamine metabolism, particularly in the amygdala.

Amygdala↗
PubMed2000

[Risk factors and effect of reperfusion therapy on left ventricular free wall rupture following acute myocardial infarction].

Reperfusion therapy is one of the most effective treatments for acute myocardial infarction, but the effect on left ventricular free wall rupture remains to be determined. This study tried to clarify the risk factors and effect of reperfusion therapy on the risk of free wall rupture following acute myocardial infarction. 2,671 consecutive patients with acute myocardial infarction admitted to our hospital were examined. Incidence of free wall rupture showed no degenerative change(0 to 5.8%; mean 2.1%). The 1,269 consecutive patients from 1985 to 1995 were examined closely to evaluate risk factors and the effect of reperfusion therapy on the risk of free wall rupture. Fourteen patients who underwent emergent coronary artery bypass surgery were excluded. Free wall rupture was found in 25 patients (2.0%). Multivariate analysis confirmed that high age(> or = 70 years) and first acute myocardial infarction were independent risk factors of free wall rupture (odds ratio 3.62, p = 0.003; odds ratio 7.69, p = 0.046, respectively). The incidence of free wall rupture in the conservative therapy group(n = 799) was 2.1%, successful reperfusion group(n = 373) was 0.5%, and unsuccessful reperfusion group(n = 83) was 7.2% with significant statistical differences(p < 0.01). There was no statistical difference between the direct percutaneous transluminal coronary angioplasty group(n = 84, 3.6%) and the thrombolysis group(n = 372, 1.3%). Successful reperfusion was the only independent factor in the reperfusion therapy group that reduced the incidence of free wall rupture(odds ratio = 0.07, p = 0.001). We conclude that reperfusion of the infarct-related artery and more intensive management of unsuccessful reperfusion is important to prevent free wall rupture following acute myocardial infarction.

Age Factors↗
PubMed2000

[Surgical treatment for mitral regurgitation: mid-term outcome following mitral valve repair].

Mid-term results of mitral valve repair for mitral regurgitation were evaluated in 173 consecutive patients (mean age 53 years, 107 males, 66 females) treated from July 1991 to March 1998. Pathological causes of the mitral valve disease were degenerative in 118 patients, infective endocarditis in 25, rheumatic in 13, and ischemic in 8 (ischemic cardiomyopathy in 7). The principal technique was chordal replacement with expanded polytetrafluoroethylene sutures for prolapse of the anterior leaflet, and Carpentier's sliding leaflet technique for prolapse of the posterior leaflet. Most patients received ring annuloplasty with a rigid ring and flexible band (physiological remodeling annuloplasty). Intraoperative transesophageal echocardiography was used after 1993. There were 7 operative deaths (4%) and 7 mitral valve replacements (4%) during the same operation. Successful repair was achieved in 96% of patients with mitral regurgitation. Mean follow-up was 35 months (range 2 to 78 months). Survival at 6 years was 85 +/- 10% of all patients, 98 +/- 2% in degenerative cases. Six patients required reoperation (1.2%/patient-year) and mean time interval between initial operation and reoperation was 33.1 months. Four patients with atrial fibrillation had thromboembolic events (0.8%/patient-year). There were no anticoagulant-related complications. Freedom from reoperation and all valve-related event at 6 years was 88 +/- 6% and 84 +/- 6%. Late postoperative Doppler echocardiography revealed satisfactory results in 93% of the patients. Mitral valve repair using chordal replacement, sliding plasty and ring annuloplasty provides excellent mid-term results.

Disease-Free Survival↗
PubMed1999

Mutations of a novel human RAD54 homologue, RAD54B, in primary cancer.

Association of breast tumor susceptibility gene products BRCA1 and BRCA2 with the RAD51 recombination protein suggested that cancer could arise through defects in recombination. The identification of NBS1, responsible for Nijmegen breakage syndrome, from the MRE11/RAD50 recombination protein complex also supports this hypothesis. However, our mutation analysis revealed that known members of the RAD52 epistasis group are rarely mutated in human primary cancer. Here we describe the isolation of a novel member of the SNF2 superfamily, characterized with sequence motifs similar to those in DNA and RNA helicases. The gene, designated RAD54B, is significantly homologous to the RAD54 recombination gene. The expression of RAD54B was high in testis and spleen, which are active in meiotic and mitotic recombination. These findings suggest that RAD54B may play an active role in recombination processes in concert with other members of the RAD52 epistasis group. RAD54B maps to human chromosome 8q21.3-q22 in a region associated with cancer-related chromosomal abnormalities. Homozygous mutations at highly conserved positions of RAD54B were observed in human primary lymphoma and colon cancer. These findings suggest that some cancers arise through alterations of the RAD54B function.

Adenocarcinoma↗
PubMed1999

Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls.

We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.

Adolescent↗
PubMed1998

Effect of mental stress on plasma homovanillic acid in healthy human subjects.

Plasma levels of homovanillic acid (pHVA) have been suggested to provide a measure of dopaminergic activity in the central nervous system. The present study investigated the effect of mental stress by the Kraepelin test, a test of continuous arithmetic addition of single-digit figures for 30 min, on pHVA levels in 13 male psychiatrically normal healthy volunteers. Following an overnight fast and restricted physical activity, plasma samples were collected immediately before and after the administration of the Kraepelin test. Plasma HVA levels following the administration of the Kraepelin test were significantly lower than the pretest pHVA levels. The percent change in pHVA levels by the Kraepelin test positively correlated with pretest pHVA levels. The observed reduction in pHVA levels by mental stress in normal subjects may reflect some aspects of a dopamine-dependent restitutive system in the brain.

Adult↗
PubMed1998

[Pitfalls in echocardiographic diagnosis of mitral bileaflet prolapse].

Preoperative echocardiography provides good planning information for successful repair of mitral valve regurgitation, but identifying the prolapse of both the anterior and posterior leaflets is sometimes difficult. To clarify the cause of this problem, preoperative echocardiographic findings and intraoperative observations of the prolapse were analyzed in 124 patients with non-rheumatic pure mitral regurgitation. In 48 patients with final diagnoses of bileaflet prolapse, 16 (33%) were considered to have only single leaflet prolapse before the operation. Anterior leaflet prolapse was overlooked in 14, and prolapse of either of its commissural segments was the least detectable by echocardiography. Chordal rupture was seen more in the posterior leaflet than in the anterior leaflet. Movement of the anterior leaflet may be influenced by a prolapsed and hypermobile posterior leaflet and/or regurgitant jet flow caused by the posterior leaflet prolapse.

Chordae Tendineae↗
PubMed1997

Prediction of short-term changes in symptom severity by baseline plasma homovanillic acid levels in schizophrenic patients receiving clozapine.

The relationship between pretreatment levels of plasma homovanillic acid (pHVA) and the outcome of clozapine treatment was studied in 18 male patients with schizophrenia who were resistant to treatment with conventional neuroleptics. After 6 months of clozapine treatment, 7 patients demonstrated > or = 20% decrease in the Brief Psychiatric Rating Scale (BPRS) (responders), while 11 patients did not (non-responders). Responders and non-responders did not differ with respect to the baseline pHVA level. The BPRS Positive Symptom scores at 6 weeks and 3 months, but not those at baseline and 6 months, following initiation of clozapine treatment negatively correlated with pHVA levels for all patients. The correlations became stronger when only responders were included. No significant correlation between Positive Symptom scores and pHVA levels was observed for non-responders. The BPRS Total and Negative Symptom scores did not correlate with pHVA for all patients, responders or non-responders at any time. The percent decrease in the BPRS Positive Symptom scores from baseline at 6 weeks following clozapine treatment correlated significantly with pHVA levels in responders. These results suggest that pretreatment levels of pHVA can be used to predict relatively short-term changes in the positive symptoms of patients with schizophrenia receiving clozapine treatment, particularly for clozapine responders.

Adult↗
PubMed1997

Sex differences in plasma homovanillic acid levels in schizophrenia and normal controls: relation to neuroleptic resistance.

Plasma homovanillic acid (pHVA) levels were compared in a large number of neuroleptic-resistant and -responsive schizophrenic patients (male/female = 161/46) and normal controls (67/27), and correlated with various measures of psychopathology. Psychopathology was evaluated with the brief psychiatric rating scale, the Schedule for Affective Disorders and Schizophrenia-Change version (SADS-C) and SADS-C Global Assessment Scale, the Scale for Assessment of Negative Symptoms, the Scale for Assessment of Positive Symptoms (SAPS), and the Quality of Life Scale. No significant differences in pHVA levels between neuroleptic-resistant (n = 104) or -responsive (n = 103) schizophrenic patients, and normal controls, were found; however, there was a main effect for sex, due to higher pHVA levels in women than men. There were no diagnosis x gender or age effects on pHVA levels. No significant correlations were observed between psychopathology ratings and baseline pHVA levels, except with the Hallucinations subscale of SAPS in neuroleptic-responsive patients. Neither duration of neuroleptic washout nor plasma prolactin levels correlated with pHVA levels. Further studies on the origin and significance of the gender difference in pHVA are indicated.

Antipsychotic Agents↗
PubMed1997

The effect of streptozotocin-induced diabetes on dopamine2, serotonin1A and serotonin2A receptors in the rat brain.

The effect of streptozotocin (STZ)-induced diabetes and a combination of chronic treatment with haloperidol (HPD) on dopamine (DA)D2, serotonin (5-HT) 5-HT1A and 5-HT2A receptors was investigated in rat brain. Rats were randomly assigned to one of four groups: vehicle-vehicle, STZ-vehicle, vehicle-HPD, and STZ-HPD groups. Four weeks after single administration of STZ (65 mg/kg IV) or vehicle (citrate buffer), rats received depot HPD (4 mg/kg IM) or vehicle (sesame oil) once a week for 4 weeks. Sixteen days after the last injection of HPD or vehicle, rats were sacrificed, and the density of binding sites was determined using [3H]spiperone as ligand in the striatum (D2),[3H]8-hydroxy-2-(di-n-propyl)-aminotetraline in the hippocampus (5-HT1A), and [3H]ketanserin in the frontal cortex (5-HT2A). The density of D2 receptors was significantly increased in the vehicle-HPD compared to vehicle-vehicle controls. However, striatal D2 receptor density of the STZ-HPD and the STZ-vehicle were not significantly different from the vehicle-vehicle group. A significant increase in cortical 5-HT2A receptor density was observed only in the group of STZ-vehicle. Treatment with STZ, HPD, or the combination thereof, did not affect the density of 5-HT1A receptors. The affinity constants for D2, 5-HT1A, and 5-HT2A receptors were not affected by any treatment. These results suggest that diabetic state may affect brain serotonergic activity via an increase in the density of 5-HT2A receptors. This may indicate an increased vulnerability to major depression in patients with diabetes. The lack of an effect of the combined chronic treatment with STZ and HPD on the D2 receptor density may correspond to the increased risk to develop tardive dyskinesia in patients with diabetes.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1996

Serotonin1A receptors are increased in postmortem prefrontal cortex in schizophrenia.

Serotonin-5-HT1A receptors were measured with [3H]8-hydroxy-2-(di-n-propyl)aminotetralin ([3H]8-OH-DPAT) in postmortem prefrontal cortex of 12 pairs of subjects with schizophrenia and age-matched control subjects. The saturation binding isotherms of [3H]8-OH-DPAT revealed high- and low-affinity binding sites. The density (Bmax) of the high-affinity sites was significantly elevated by an average of 79% in subjects with schizophrenia. The dissociation constant (Kd) of the high-affinity sites in subjects with schizophrenia was not significantly different from the control subjects. These results provide further evidence for a role of the serotonergic system in the pathophysiology of schizophrenia.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1996

Comparison of clinical outcomes of coronary artery bypass grafting and percutaneous transluminal coronary angioplasty in renal dialysis patients.

BACKGROUND: The leading cause of death in chronic renal dialysis patients is cardiovascular disease. As the number of dialysis patients increases, we are encountering more patients with severe ischemic heart disease requiring coronary intervention. METHODS: A retrospective analysis was performed of the short- and long-term clinical results in 23 coronary artery bypass grafting patients and 20 coronary angioplasty patients undergoing chronic renal dialysis. RESULTS: Among coronary bypass grafting patients, there were no hospital deaths. The graft patency rate was 100% for arterial grafts. There were four late deaths and four cardiac events. In coronary angioplasty patients, the lesion success rate was 76%. There were no hospital deaths and three major complications. The restenosis rate was 70%. There were two late deaths and 14 cardiac events. The 5-year cardiac event-free rate was 70% in coronary bypass grafting patients, significantly better than 18% in coronary angioplasty patients (p < 0.001). CONCLUSIONS: Coronary artery bypass grafting in chronic renal dialysis patients can be accomplished with a better short- and long-term outcome than coronary angioplasty, through an intensive perioperative dialysis program and extensive use of arterial grafts.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Acute myocardial infarction and silent myocardial ischemia in the elderly--clinical features and effectiveness of therapy in an era of coronary intervention].

To elucidate the clinical features of acute myocardial infarction (AMI) and post-MI silent myocardial ischemia (SMI) in the elderly, and efficacy of therapy in an era of coronary intervention, a total of 10,607 patients with AMI who were enrolled in a multicenter survey between 1982 and 1992 were examined. The elderly had a higher ratio of females, noncardiac illness, atypical symptoms at the onset of AMI, severe pump failure at admission, cardiac rupture and multivessel disease. Hospital mortality was markedly higher in patients > or = 75 years, and it was 4-fold compared with patients < 65 years. In the last 5 years, the rate of application of coronary angiography and primary PTCA significantly increased even in the very elderly. In contrast, use of thrombolysis highly diminished. Hospital mortality declined (14.6 vs 11.9%, p < 0.001) in every age group compared with the first 5 years, although it was higher in the elderly even in the last 5 years. Investigation of 642 survivors after AMI admitted to one hospital showed that the elderly had a higher incidence of SMI and post-MI angina compared with the non-elderly. Clinical features of SMI were similar in both groups. However, medical treatment was more prevalent and recurrence of MI and cardiac death during follow-up (average 27 months) were more frequent in the elderly. In this retrospective study, characteristics of AMI and SMI, and effectiveness and limitation of therapy in the elderly were clearly demonstrated. It was evident that hospital mortality of the elderly had improved, although it was still higher than the non-elderly.

Aged↗