Tsuneyuki Nakamura

Fas-Mediated Apoptosis in Adriamycin-Induced Cardiomyopathy in Rats In Vivo Study

BACKGROUND The precise molecular mechanism of Adriamycin-induced cardiomyopathy (ADR-CM) is still unknown. We address the demonstration of apoptotic myocardial cell death and the apoptosis-inducing molecules in ADR-CM induced in rats. METHODS AND RESULTS Until 8 weeks after the first administration of ADR, there was no increase in the number of labeled cells by terminal deoxynucleotidyl transferase assay (TUNEL method). Apoptotic indices increased significantly at weeks 9 and 10 in hearts of the ADR-treated group but not in those of the control group (0.42+/-0.12% versus 0.10+/-0.02% and 0.86+/-0.11% versus 0.09+/-0.04% at weeks 9 and 10, respectively). DNA ladder formation was also observed in the myocardial tissues during the late stages of the ADR-CM of rats. There was no significant difference in expression of p53 gene between the ADR group and the control group at either the message or the protein level. An overexpression of Fas antigen was shown in myocardial cells of ADR-treated hearts at weeks 9 and 10 by both Western blotting and immunofluorescent staining. Furthermore, we confirmed that neutralization of anti-Fas ligand antibody inhibited ADR-induced apoptosis. CONCLUSIONS Apoptotic cell death was observed in the hearts of ADR-CM rats, and the number of apoptotic myocardial cells increased with the deterioration of morphological findings and cardiac function, indicating that apoptosis may be an important mechanism of loss of myocardial cells and cardiac dysfunction in ADR-CM. Apoptosis in ADR-CM rats is not p53-dependent but rather is executed through a Fas-mediated pathway.

Midterm surgical results of total cavopulmonary connection : clinical advantages of the extracardiac conduit method

OBJECTIVE We evaluated the midterm surgical outcomes of intra-atrial lateral tunnel and extracardiac conduit total cavopulmonary connection to clarify the clinical superiority. METHODS Patients (n = 167) underwent total cavopulmonary connection (88 with lateral tunnel and 79 with extracardiac conduit) from November 1991 to March 1999. Survival, incidence of reoperation and late complications, exercise tolerance, hemodynamic variables, and plasma concentration of natriuretic peptide type A were compared. In the lateral tunnel group, time-related change in lateral tunnel size was investigated for its relationship to postoperative arrhythmias. RESULTS The 8-year survival was 93.2% in the lateral tunnel group and 94.9% in the extracardiac conduit group. Seven reoperations were performed in the lateral tunnel group but none in the extracardiac conduit group. Supraventricular arrhythmias developed in 14 patients (15.9%) in the lateral tunnel group and in 4 patients (5.1%) in the extracardiac conduit group (P =.003). Freedom from cardiac-related events was 72.5% in the lateral tunnel group and 89.8% in the extracardiac conduit group at 8 years (P =.0098). Hemodynamic variables and exercise tolerance were similar in both groups but plasma natriuretic peptide type A concentration, a parameter of atrial wall tension, was higher in the lateral tunnel group. In the lateral tunnel group, intra-atrial tunnel size increased by 19.4% during the 44.2-month interval and the percent increase in tunnel size was an independent predictor of supraventricular arrhythmias. CONCLUSIONS The midterm survival, hemodynamic variables, and exercise tolerance were similar and satisfactory in both lateral tunnel and extracardiac conduit groups; however, the incidence of cardiac-related events was significantly less frequent in the extracardiac conduit group. In the lateral tunnel group, careful observation is required to monitor the relationship of the dilating tendency of the intra-atrial tunnel and the development of late complications.

Apoptosis in young rats with adriamycin-induced cardiomyopathy-comparison with pirarubicin, a new anthracycline derivative

In a previous study, we demonstrated that apoptosis in rats with adriamycin (ADR)-induced cardiomyopathy occurred through a Fas-dependent pathway. Pirarubicin, a new anthracycline derivative, seems to have a lower cardiotoxicity than ADR. To investigate whether pirarubicin has a lower chronic cardiotoxicity compared with ADR, ADR or pirarubicin were injected weekly for 8 wk into young Wister rats via the tail vein. To block the Fas-Fas ligand interaction, an anti-Fas ligand antibody (FasL) was injected with ADR 7, 8, and 9 wk after first administration of ADR. In the control group, saline was injected instead of ADR. ADR significantly induced apoptosis and left ventricular dysfunction 10 wk after the first administration of ADR. Pirarubicin also induced apoptosis, however, its apoptosis was significantly (p = 0.0069) less than that induced by ADR. Fas antigen was overexpressed in the hearts of ADR and ADR+FasL groups, however, an expression of Fas antigen in the pirarubicin group was similar to the expression of Fas antigen in the control group. Thus, pirarubicin has a significantly lower chronic cardiotoxicity compared with ADR.

Pharmacokinetics of Bosentan in Routinely Treated Japanese Pediatric Patients with Pulmonary Arterial Hypertension

We evaluated the pharmacokinetics of routinely administered bosentan in 46 Japanese pediatric patients with pulmonary arterial hypertension. Plasma samples were taken twice at times corresponding to the peak and trough concentrations following repetitive oral administration. The population pharmacokinetic parameters of bosentan were estimated by use of the NONMEM program, in which a one-compartment model with repetitive bolus dosing was parameterized in terms of the oral clearance (CL/F) and elimination rate constant (k). Polymorphisms of CYP3A5, SLCO1B1, SLCO1B3, and SLCO2B1 had no significant effect on the disposition of bosentan. In addition, the pharmacokinetics of bosentan was not altered by heart failure or coadministration of sildenafil. In contrast, weight (WT)-normalized values of CL/F were correlated negatively with age (AGE). The final population mean values of CL/F and k were estimated to be 0.409 · (1 - 0.0377 · (AGE - 3.81)) · WT L/h and 0.175 h(-1), respectively.

Vasculitis induced by immunization with Bacillus Calmette‐Guérin followed by atypical mycobacterium antigen: a new mouse model for Kawasaki disease

Abstract Kawasaki disease causes systemic vasculitis. The development of skin lesions at the vaccination site with Bacillus Calmette‐Guérin (BCG) is an important diagnostic symptom. We hypothesized that infection with ubiquitous microorganisms immunogenically related to BCG might induce an immunopathologic reaction leading to the development of Kawasaki disease. Mice were first inoculated with BCG, and then secondarily inoculated 4 weeks later with crude extract from Mycobacterium intracellulare (cMI), an abundant atypical mycobacterium. Animals inoculated with BCG followed by cMI developed coronary arteritis with infiltration of inflammatory cells, whereas control animals inoculated with only cMI or BCG did not, suggesting that the immune response to the mycobacteria induced autoimmunity to the vascular wall. Intravenous injection with antibodies to peroxiredoxin II, a modulator of vascular remodeling and a suggested target for autoimmune vasculitis, also resulted in coronary arteritis, but only after prior inoculation with BCG. Tumor necrosis factor‐α, MCP1 and interferon‐γ production were significantly higher in the animals inoculated with BCG than in the control groups (P<0.05). BCG immunization was required for the development of coronary arteritis, suggesting that these cytokines might play important roles. The results indicate that BCG induces primary autoimmunity and stimulates cytokine induction, and that atypical mycobacterial infection boosts the autoimmunity resulting in coronary arteritis.

Bosentan induces clinical and hemodynamic improvement in candidates for right-sided heart bypass surgery

OBJECTIVE To investigate the efficacy of bosentan in patients with single-ventricle physiology who were unable to undergo right-sided heart bypass surgery because of high pulmonary vascular resistance and pulmonary artery pressure. METHODS Eight patients with single-ventricle physiology (2 male and 6 female; aged 7 months to 5 years, median 1 year) were enrolled. Prior surgical interventions included pulmonary artery banding in 4 patients, Blalock-Taussig shunt operation in 2 patients, and bidirectional Glenn operation in 5 patients. Right-sided heart bypass surgery was contraindicated for all patients because of high pulmonary vascular resistance and pulmonary artery pressure. RESULTS Bosentan therapy successfully reduced pulmonary artery pressure and pulmonary vascular resistance in all patients. Mean pulmonary artery pressure at baseline and after bosentan therapy was 21.1 +/- 7.2 mm Hg and 11.9 +/- 4.1 mm Hg, respectively (P < .01). Mean pulmonary vascular resistance index at baseline and after bosentan therapy was 5.7 +/- 3.3 U/m(2) and 1.3 +/- 0.4 U/m(2), respectively (P < .01). Mean pulmonary vascular resistance/systemic vascular resistance at baseline and after bosentan therapy was 0.25 +/- 0.11 and 0.07 +/- 0.03, respectively (P < .01). All patients had improved clinical symptoms and underwent successful Fontan operations. CONCLUSION Bosentan induces mid-term clinical and hemodynamic improvement in patients with single-ventricle physiology and elevated pulmonary vascular resistance and pulmonary artery pressure. Bosentan therapy may increase the surgical options and improve outcomes in candidates for right-sided heart bypass surgery.

Analysis of children with Chlamydophila (Chlamydia) pneumoniae and Mycoplasma pneumoniae respiratoryinfections by real-time PCR assay and serological tests

We examined 73 children with respiratory infections for Chlamydophila (Chlamydia) pneumoniae and Mycoplasma pneumoniae using real‐time PCR assay and serological tests. C. pneumoniae and M. pneumoniae infections were found in 11 (15.1%) and 6 (8.2%) cases, respectively. The sensitivities and specificities of real‐time PCR versus definite diagnosis of acute infection were 63.6% and 100% for C. pneumoniae, and 100% and 100% for M. pneumoniae, respectively. C. pneumoniae PCR‐negative results appeared to be due to poor growth of the organism. The sensitivity and specificity of ImmunoCard tests were 33.3% and 82.1%, respectively, indicating that the efficacy of rapid diagnosis was disputable. The present results suggest that real‐time PCR is suitable for rapid diagnosis as a first screening test to determine first‐line antibacterial agents to be used against these infectious diseases.

Plasma concentrations of tadalafil in children with pulmonary arterial hypertension.

Background: There is no report documenting the plasma concentrations of tadalafil in children. This study was performed to evaluate the variability in the pharmacokinetics of tadalafil in children with pulmonary arterial hypertension (PAH) treated routinely with the drug. Methods: Plasma samples were taken twice (post- and predose) after repetitive oral administration, and the pharmacokinetic parameters (CL/F and V/F) in individual patients were estimated by the Bayesian method using the nonlinear mixed effects model. We also determined the unbound concentration of tadalafil using ultrafiltration. Results: Tadalafil was administered to 23 children aged between 0.25 and 17.4 years, with a mean age of 3.58 years. The mean (±SD) daily dose of tadalafil was 0.97 ± 0.41 mg/kg. Sixteen of the 23 children received bosentan concomitantly. The mean CL/F and V/F values of tadalafil were 0.149 L·h−1·kg−1 and 1.87 L/kg, respectively, which were higher than those reported in adults. No effects of age, bosentan, or the estimated glomerular filtration rate were observed on the CL/F value, indicating that other residual factors might account for the interindividual variability among children with PAH. The unbound tadalafil concentrations of the postdose samples ranged from 5.9 to 146 (46.9 ± 37.1) nmol/L, higher than the reported IC50 value of this phosphodiesterase-5 drug for humans (2–4 nmol/L, corresponding to 0.8–1.6 ng/mL). Conclusions: We demonstrated variability in the total and unbound plasma concentrations of tadalafil in children. However, all children received the empirical doses of the drug; a mean dose of 0.97 mg·kg−1·d−1 showed sufficient unbound concentrations needed for half-maximal inhibition of human phosphodiesterase-5 in vitro. These observations may provide information for the proper use of tadalafil to treat children with PAH.

Three-dimensional computed tomographic findings of bilateral tracheal bronchus.

A newborn male was admitted with cyanosis and respiratory distress. Echocardiography showed a right heart isomerism associated with a single right ventricle, a double-outlet right ventricle, and pulmonary atresia. Chest X-ray demonstrated severe left upper lobe emphysema and a shift of the mediastinal structures to the right. Two-dimensional computed tomography (CT) exhibited left upper lobe emphysema and right upper lobe atelectasis. Three-dimensional (3D) spiral CT angiography showed a bilateral tracheal bronchus. The left tracheal bronchus branch was compressed between the descending aorta and the ductus arteriosus. After a right arteriopulmonary shunt operation, the patient’s respiratory condition improved dramatically, with spontaneous closure of the ductus arteriosus. Subsequently, 3D-CT clearly exhibited the disappearance of tracheal compression. This combination of bilateral tracheal bronchus and congenital heart anomaly is extremely rare. The 3D-CT is a powerful noninvasive means for dynamically demonstrating the special relationships of arterial and tracheal anomalies.

A Large Lateral Parapharyngeal Heterotopic Brain Tissue Extending Into the Intracranial Area

antibiotics and oral corticosteroids has been established in the practice of pediatric medicine, and in two of our three patients, antibiotic therapy seemed to lead to resolution of symptoms. However, chronic antibiotic prophylaxis has to date not been shown to prevent exacerbations of obsessive-compulsive disorder, although it ultimately may become a standard treatment for the subset of children prone to development of recurrent symptoms. Our cur-