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Biomedical subjects

Toshiki Kobayashi

Publications and source records attributed to Toshiki Kobayashi.

14 recordsLinked to original sources
PubMed2006

Cardiac rest and reserve function in patients with Fontan circulation.

OBJECTIVES: In the present study, we systematically tested cardiac rest and reserve function in patients with Fontan physiology to check for inherent limitations of this circulation. BACKGROUND: Details of the mechanisms of cardiac performance that could account for adverse outcome after Fontan surgery are not well understood. METHODS: The subjects were 17 Fontan patients with good functional status (Fontan group) and 20 patients with normal two-ventricle circulation (control group). We examined baseline ventricular contractility, diastolic function, and loading factors, and examined changes in those parameters in response to increased heart rate (HR) due to atrial pacing and in response to beta-adrenergic stimulation, using ventricular pressure-area relationships during preload reduction. RESULTS: At baseline, the Fontan patients exhibited minimal abnormality of cardiac properties, but the significant increase in afterload resulted in decreased cardiac index. In addition, Fontan circulation was associated with limited inotropic response and worsening of diastolic filling with increased HR, leading to decreased systolic pressure and elevation of central venous pressure at higher HRs (p < 0.05 vs. control). Furthermore, beta-adrenergic reserve was markedly decreased in the Fontan group, compared with controls, owing to limited preload reserve rather than limited contractile reserve. CONCLUSIONS: Because normal ventricular-vascular interaction and augmentation of cardiac performance during increased HR and adrenergic stimulation are important for maintaining cardiac output and exercise capacity, the present results may have important implications for the mechanisms underlying adverse outcome after Fontan surgery. Thus, improvement of long-term prognosis of patients after Fontan surgery requires the development of medical interventions that can overcome such limitations inherent in Fontan circulation.

Child↗
PubMed2005

Regional brain cerebral glucose metabolism and temperament: a positron emission tomography study.

Personality, and in particular temperament, is thought to have a biological basis. In the present study, the relationships between regional brain glucose metabolism and temperament have been investigated. Regional brain glucose metabolism was measured using [18F] fluorodeoxyglucose positron emission tomography in 31 healthy subjects. Temperament was assessed using the Temperament and Character Inventory. Temperament dimensions were observed to be significantly correlated with specific brain regions. In particular, novelty seeking was significantly correlated with the superior temporal gyrus, inferior parietal lobule, and the precuneus, which have been reported to be related with impulsiveness, while reward dependence was significantly correlated with the caudate head, which has been shown to be associated with reward processing. The various aspects of temperament may have biological bases in the specific brain regions. The accumulation of results from studies of this kind should provide further evidence connecting personality traits with their biological bases.

Adult↗
PubMed2005

Arterial hemodynamics in patients after Kawasaki disease.

BACKGROUND: Histopathological findings in the acute stage of Kawasaki disease (KD) indicate widespread vascular inflammation that involves not only coronary arteries but also systemic arteries. This may cause changes in systemic arterial wall properties after KD, which could have adverse effects on arterial hemodynamics (an important predictor of cardiovascular morbidity and mortality). METHODS AND RESULTS: Systemic arterial hemodynamics were investigated by measuring aortic input impedance during cardiac catheterization in 42 KD patients who had developed coronary artery lesions (CALs) in the acute stage of KD. The KD patients were subdivided into 2 groups according to the angiographic findings (group 1A, 26 patients with persistent CALs; group 1B, 16 patients with regressed CALs), and results were compared with those of 36 referents (group 2). Compared with referents, characteristic impedance was significantly higher for KD patients (137.0+/-5.1, 125.7+/-8.2, and 97.9+/-4.1 dyne x s x cm(-5) x m2 for group 1A, group 1B, and group 2, respectively), and total peripheral arterial compliance indexed to age-specific values was significantly lower for KD patients (group 1A 72.9+/-4.2% of normal; group 1B 70.6+/-5.9% of normal; group 2 97.7+/-4.0% of normal; for both variables, P<0.05 for each KD group versus group 2; P=NS between KD groups), which suggests that both central and peripheral arterial wall stiffness increase after KD regardless of persistence of CALs. Also, indices of arterial wave reflection (reflection coefficient, reflection factor, and augmentation index) were all significantly higher in KD patients than in referents (P<0.05), with the result that the aortic pressure waveforms of the present KD patients resembled those generally observed in the elderly. In addition, levels of circulating markers of endothelial dysfunction (ACE and von Willebrand factor) were associated with increased vascular stiffening in KD patients but not in referents. CONCLUSIONS: These results indicating abnormal arterial hemodynamics after KD highlight the importance of regular monitoring of the systemic arterial bed and potentially relevant cardiovascular events in long-term follow-up of KD.

Adolescent↗
PubMed2005

Recovery from idiopathic thrombocytopenic purpura (ITP) following right hemicolectomy for mucocele of appendix.

A 61-year-old woman with a 2-year medication-free history of idiopathic thrombocytopenic purpura was referred to our hospital complaining of right lower abdominal pain. The platelet count was about 3-4x10(4)/mm3. This patient was diagnosed with mucocele of the appendix on computed tomography and colonoscopy. We performed only right hemicolectomy without splenectomy. The pathological diagnosis was mucinous cystadenoma of the appendix. The platelet count increased to 18.1x10(4)/mm3 on postoperative-day 7, and remained stable, at 20-24x10(4)/mm3, for 14 months after the operation. Platelet-associated immunoglobulin G decreased remarkably after the operation, to 30.2 ng/10(7) cells, from 240 ng/10(7) cells preoperatively. We describe the first case of recovery from idiopathic thrombocytopenic purpura following right hemicolectomy performed for mucocele of the appendix. Considering our patients clinical course, it is possible that mucinous cystadenoma of the appendix may have influenced the thrombocytopenia. Findings in this patient suggest that mucocele of the appendix may be associated with a new diagnosis and idiopathic thrombocytopenic purpura treatment.

Appendectomy↗
PubMed2005

Usefulness of selective contrast echocardiography and selective scintigraphy for the evaluation of pulmonary arteriovenous fistula in a patient with systemic arterial supply to a normal lung.

To determine a surgical procedure for the correction of a systemic arterial supply to a normal lung, it is important to evaluate whether the patient has a pulmonary arteriovenous fistula. In this article, the authors report for the first time a patient in which selective contrast echocardiography and selective perfusion scintigraphy from an abnormal artery clearly demonstrated and quantified the pulmonary arteriovenous fistula. The authors believe that these methods are useful in determining the appropriate operative procedure for this condition.

Aorta, Thoracic↗
PubMed2005

Vasopressin in the treatment of vasodilatory shock in children.

BACKGROUND: Many recent studies suggest that vasopressin deficiency is an important cause of catecholamine-resistant hypotension with vasodilation in adults, but little is known about vasopressin deficiency in children. METHODS: To clarify the usefulness of vasopressin administration in pediatric cathecolamine-resistant hypotension with preserved ventricular contractility, urinary output and blood pressure response to vasopressin were retrospectively analyzed in 12 consecutive patients (15 instances) who were treated with vasopressin. The causes of vasodilation were central nervous system disturbance (n = 5), side-effect of drug (n = 5), and infection (n = 5). Plasma vasopressin concentration was measured six times before vasopressin administration and five times during vasopressin administration. RESULTS: Patients were divided into four groups according to their response to vasopressin administration. In group 1 (n = 5), urinary output increased to > 3 mL/kg per h within 3 h after vasopressin administration. In group 2 (n = 4), urinary output increased to > 3 mL/kg per h from 3 to 5 h after vasopressin administration. In group 3 (n = 4), urinary output did not increase to > 3 mL/kg per min within 5 h after vasopressin administration, but systolic blood pressure increased to > 120% of the level at the time of vasopressin administration. All remaining patients were classified into group 4 (n = 3). Plasma vasopressin concentration were low considering the markedly hypotensive state in all six instances. Plasma vasopressin concentration during vasopressin administration were significantly increased compared with before administration (P < 0.05). No apparent side-effects were observed in this series. CONCLUSION: Vasopressin deficiency may occur in catecholamine-resistant hypotension of pediatric patients due to various causes including central nervous system disturbance, drug induced hypotension and sepsis. Small doses of vasopressin administration seems to be very effective in such conditions by increasing blood pressure and urinary output.

Adolescent↗
PubMed2003

Dilated cardiomyopathy in a 3-year-old girl with a terminal deletion, 46,XX,del(3)(q27-qter), of the long arm of chromosome 3.

UNLABELLED: We report a case in which a 3-year-old girl with terminal deletion of the long arm of chromosome 3 had dilated cardiomyopathy, a complication that has not previously been reported in association with this chromosome abnormality. In addition to cardiomyopathy, she had intrauterine growth retardation, small eyes and mouth, a broad nose, thin lips, low-set ears, a short neck and overlapping second toes. CONCLUSION: due to the paucity of reported cases of 3q deletion, and the clinical variability of such cases, identification of a distinct 3q phenotype (including cardiac complications) remains elusive.

Cardiomyopathy, Dilated↗
PubMed2003

Plasminogen activator inhibitor-1 in patients with Kawasaki disease: diagnostic value for the prediction of coronary artery lesion and implication for a new mode of therapy.

Kawasaki disease (KD) in children takes the form of acute systemic vasculitis, which causes coronary artery dilation and aneurysm formation in 10% to 15% of the patients. We have recently shown that matrix metalloproteinases (MMPs) are intimately involved in coronary arterial wall destruction and the resultant formation of coronary artery lesions (CALs) in this disease. Plasminogen activators (PAs) are known to be a major pathway of MMP activation, and this suggests that their inhibitor, plasminogen activator inhibitor-1 (PAI-1), also plays important roles in the development of CALs in KD. The present study was conducted to test the hypothesis that circulating levels of PAI-I are related to CAL formation in KD. Plasma levels of PAI-1 were measured by enzyme-linked immunoassay in 37 KD patients without CALs (group 1) and 7 KD patients with CALs (group 2). Blood samples were obtained before and after i.v. gammaglobulin therapy (IVGG), and in the convalescent stage. Levels of PAI-1 were significantly higher in KD patients before IVGG than in 18 age-matched healthy control subjects (p < 0.01). More importantly, both pre-IVGG and post-IVGG levels of PAI-1 were significantly higher in group 2 than in group 1 (p < 0.01). Furthermore, PAI-1 levels of 9 patients from group 1 who showed pre-IVGG PAI-1 levels higher than the minimum PAI-1 level in group 2 significantly decreased after IVGG, whereas PAI-1 levels of group 2 patients remained persistently elevated, further suggesting a close association between PAI-1 and CAL development in KD. Thus, PAI-1 may be useful as a predictive marker for CAL development in KD. Studies of the effects of PA inhibition on coronary outcome may provide evidence that PA is a viable therapeutic target for the prevention of KD-related CALs.

Coronary Vessels↗
PubMed2002

Age-associated changes in arterial elastic properties in children.

UNLABELLED: Age-associated changes in pulsatile components of the arterial system in normal children have not previously been studied. The purpose of the present study was to establish reference ranges for age-associated changes in arterial pulsatile properties in children. Arterial compliance (C(A)) and stiffness of the proximal aorta were estimated from data obtained by cardiac catheterisation in 112 paediatric patients (age range, 6 months to 20 years) who were considered to have normal systemic vascular beds. C(A) was calculated by the area method, using ascending aortic pressure tracings. Aortic wall stiffness was evaluated using the pressure-strain elastic modulus (Ep). C(A) significantly increased with age (C(A) =0.06 5 x age +0.86, r=0.71, P<0.001). However, the value of C(A)/BSA, which represents normalisation of C(A) to body surface area (BSA) (to eliminate factors associated with development of arterial size), significantly decreased with age and declined fastest during the first several years of life, suggesting an increase in arterial wall stiffness with increasing age in children. Ep also significantly increased with age (Ep =9.8 x age +177, r=0.50, P<0.001). CONCLUSION: these findings suggest that both peripheral and proximal arterial wall distensibility in children decline after birth, although total arterial buffering capacity increases. The present results provide the first quantification of in vivo age-associated changes in arterial elastic properties in children, and are potentially useful as a reference for future studies of patients with diseases that involve the vascular system.

Adolescent↗
PubMed2002

Ventricular afterload and ventricular work in fontan circulation: comparison with normal two-ventricle circulation and single-ventricle circulation with blalock-taussig shunts.

BACKGROUND: Recent studies have indicated that there are inherent limitations associated with Fontan physiology. However, there have been no quantitative analyses of the effects of right heart bypass on ventricular afterload, hydraulic power, and resultant overall hemodynamics. Methods and Results- During routine cardiac catheterization, aortic impedance and ventricular hydraulic power were determined, both at rest and under increased ventricular work induced by dobutamine, in 17 patients with Fontan circulation, 15 patients with a single ventricle whose pulmonary circulation was maintained only by Blalock-Taussig shunts, and 13 patients who had normal 2-ventricle circulation. Both vascular resistance (nonpulsatile load on the ventricle) and pulsatile components of ventricular afterload (represented by low-frequency impedance) were significantly higher in the Fontan group than in the other groups (P<0.01), and this was associated with decreased cardiac output in the Fontan patients. In addition, hydraulic power cost per unit forward flow was 40% lower in the 2-ventricle circulation than in the single-ventricle circulation, suggesting lower ventricular efficiency in single-ventricle circulation attributable to the lack of a pulmonary ventricle. Furthermore, in the Fontan group, beta-adrenergic reserve was markedly decreased because of a limited preload reserve. CONCLUSIONS: Fontan physiology is associated with disadvantageous ventricular power and afterload profiles and has limited ventricular reserve capacity. Thus, to improve the long-term prognosis of patients after Fontan surgery, future research should be conducted into medical interventions that can overcome these limitations inherent in Fontan circulation.

Adrenergic beta-Agonists↗
PubMed2002

CATCH 22 Syndrome.

CATCH 22 syndrome is characterized by cardiac defects, abnormal facial features, thymic hypoplasia, cleft palate, and hypocalcemia. It results from a deletion within chromosome 22q11. This syndrome is not a simple disease. It includes DiGeorge syndrome, conotruncal anomaly face syndrome, and velocardiofacial syndrome. The authors report two cases of CATCH 22 syndrome.

Abnormalities, Multiple↗