Yoshikazu Kaji

Detection of cardiovascular risk factors by indices of obesity obtained from anthropometry and dual-energy X-ray absorptiometry in Japanese individuals

OBJECTIVE: To determine the cut-off points of indices of obesity for detecting hypertension, dyslipidemia and diabetes mellitus in Japanese individuals.DESIGN: Cross-sectional study.SUBJECTS: A total of 2728 Japanese individuals (768 males and 1960 females, aged 20–79 y) who attended the Fukuoka Health Promotion Center, Japan for health check-up.MEASUREMENTS: Body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR) were measured. Percentage fat mass (%FM), trunk fat mass (FMtrunk) and trunk fat mass–leg fat mass ratio (FMtrunk/FMlegs) were obtained by dual-energy X-ray absorptiometry (DXA). Cardiovascular risk factors were determined by blood pressure, serum lipids, fasting blood glucose and hemoglobin A1C.RESULTS: The cut-off points of BMI, WC and WHR were around 23.5 kg/m2, 84 cm and 0.9 for males, and 22.5 kg/m2, 72 cm and 0.8 for females. The cut-off points of %FM, FMtrunk and FMtrunk/FMlegs were around 24%, 8 kg and 1.6 for males, and 35%, 9 kg and 1.4 for females. WHR and FMtrunk/FMlegs most accurately detected the risk factors.CONCLUSIONS: For Japanese individuals, the cut-off points for detecting cardiovascular risk factors are lower than the criteria by the World Health Organization. Indices of fat distribution detected the cardiovascular risk factors more accurately than those of overall adiposity. The accuracy of detecting the risk factors was comparable between the anthropometric indices and indices obtained by DXA.

Purified human hematopoietic stem cells contribute to the generation of cardiomyocytes through cell fusion

To obtain insights into the cardiomyogenic potential of hematopoietic tissue, we intravenously (i.v.) injected purified hematopoietic stem/progenitor cells into newborn recipients that may fully potentiate the developmental plasticity of stem cells. Transplantation of mouse bone marrow (BM) lineage antigen‐negative (Lin−) cells resulted in the generation of the cells that displayed cardiomyocyte‐specific antigenic profiles and contractile function when transplanted into syngeneic newborn recipients. To clarify the mechanism underlying the cardiomyogenic potential, green fluorescent protein (GFP)‐labeled BM Lin−ScaI+ hematopoietic progenitors were transplanted into neonatal mice constitutively expressing cyan fluorescence protein (CFP). Lambda image acquisition and linear unmixing analysis using confocal microscopy successfully separated GFP and CFP, and revealed that donor GFP+ cardiomyocytes coexpressed host‐derived CFP. We further reconstituted human hemopoietic‐ and immune systems in mice by injecting human cord blood (CB)‐derived Lin−CD34+CD38− hematopoietic stem cells (HSCs) into neonatal T cell−B cell−NK cell− immune‐deficient NOD/SCID/IL2rγnull mice. Fluoroescence in situ hybridization analysis of recipient cardiac tissues demonstrated that human and murine chromosomes were colocalized in the same cardiomyocytes, indicating that cell fusion occurred between human hematopoietic progeny and mouse cardiomyocytes. These syngeneic‐ and xenogeneic neonatal transplantations provide compelling evidence that hematopoietic stem/progenitor cells contribute to the postnatal generation of cardiomyocytes through cell fusion, not through transdifferentiation.— Ishikawa, F., Shimazu, H., Shultz, L. D., Fukata, M., Nakamura, R., Lyons, B., Shimoda, K., Shimoda, S., Kanemaru, T., Nakamura, K‐i., Ito, H., Kaji, Y., Perry, A. C. F., Harada, M. Purified human hematopoietic stem cells contribute to the generation of cardiomyocytes through cell fusion. FASEB J. 20, E11–E17 (2006)

Weight Reduction Decreases Soluble Cellular Adhesion Molecules In Obese Women

1. Obesity is known to increase the risk for atherosclerotic diseases. Serum levels of cellular adhesion molecules are reported to be indices of atherosclerosis. The aim of the present study was to assess the effect of weight reduction on soluble intercellular adhesion molecule‐1 (sICAM‐1) and soluble E‐selectin (sE‐selectin).

Radiofrequency catheter ablation of left ventricular outflow tract tachycardia from the coronary cusp: A new approach to the tachycardia focus.

Transcoronary Cusp Ablation of VT. Introduction: Idiopathic ventricular tachycardia (VT) originating from the left ventricular outflow tract (LVOT) is rare. Previously reported were two cases of LVOT tachycardia which were treated with radiofrequency (RF) catheter ablation through endocardial aortomitral continuity. We report here a case of a repetitive LVOT tachycardia in which the QRS morphology during VT exhibited an atypical left bundle branch block and inferior axis. Pace mapping revealed that the origin of this VT was very close to the left sinus of Valsalva. Transcoronary cusp RF catheter ablation abolished the VT in this patient and is a new approach for the treatment of this kind of VT. The application of this approach to the other types of VT has yet to he determined.

Shift work modifies the circadian patterns of heart rate variability in nurses

OBJECTIVE The influence of shifting the work-sleep cycle on the circadian rhythm of cardiac autonomic activity was investigated by the spectral analysis of heart rate variability (HRV). METHODS The subjects were 10 healthy Japanese female nurses aged 33+/-3 (S.D.) years. The subjects underwent ambulatory 24-h electrocardiogram (ECG) recordings on the days of day shift (working from 08:00 to 17:00 h) and night shift (working from 21:40 to 08:40 h). Variables of the frequency domain of HRV were calculated for three activity states (work, awake but not working, and sleep). RESULTS The mean values of HRV variables over 24 h were not different between day shift and night shift. For both shifts, variables related to the sympathetic control (low frequency component in normalized units and low/high frequency component ratio) were the largest during the work period and the smallest during the sleep period, while an opposite order was present for variables related to the vagal control (high frequency component in absolute value and normalized units). HRV variables in each activity state were not different between the two shifts. CONCLUSIONS The circadian rhythm of cardiac autonomic activity is largely modified by the level of physical activity regardless of the clock hour, which may have clinical implications when studying the circadian fluctuations of the onset of cardiovascular disease in shift workers.

The Polycomb-group gene Rae28 sustains Nkx2.5/Csx expression and is essential for cardiac morphogenesis

The Polycomb-group (PcG) gene Rae28 is a mammalian homologue of the Drosophila gene polyhomeotic. PcG genes are known to maintain transcription states, once initiated, probably by regulating chromatin structure. Since homozygous Rae28-deficient (Rae28(-/-)) mice displayed cardiac anomalies similar to congenital heart diseases in humans, we examined the role of Rae28 in cardiac morphogenesis at the molecular level. In Rae28(-/-) embryos, expression of the cardiac selector gene Nkx2.5/Csx (Nkx2.5) was initiated properly but was not sufficiently sustained later in development. This impaired expression of Nkx2.5 in the maintenance phase proved to have a crucial effect on cardiac morphogenesis, as demonstrated by the results of a genetic complementation experiment in which the cardiac anomalies were suppressed by overexpression of human NKX2.5/CSX1 in Rae28(-/-) embryos. Ubiquitous expression of exogenous Rae28 likewise restored the impaired Nkx2.5 expression in Rae28(-/-) embryos, further supporting the notion that Rae28 sustains Nkx2.5 expression in cardiomyocytes. Thus, our data show that a mammalian PcG gene can play a key role in organogenesis by helping to maintain the expression of a selector gene.

Excess accumulation of body fat is related to dyslipidemia in normal-weight subjects.

OBJECTIVE: To assess the relationship of fat mass (FM) and its distribution to hypertension and dyslipidemia in normal-weight Japanese individuals.DESIGN: Cross-sectional study.SUBJECTS: Apparently healthy Japanese subjects with a body mass index (BMI) between 20 and 23.5 kg/m2 (265 males and 741 females, age 21–69 y).MEASUREMENTS: BMI, waist circumference (WC), waist-hip ratio (WHR), systolic and diastolic blood pressure, serum levels of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C) and triglyceride (TG) were measured. Low-density lipoprotein-cholesterol (LDL-C) was calculated by the Friedewald formula. Percentage fat mass (%FM) and trunk fat mass–leg fat mass ratio (FMtrunk/FMlegs) were obtained by dual-energy X-ray absorptiometry.RESULTS: WC, WHR, %FM and FMtrunk/FMlegs were significantly correlated with TC, LDL-C, HDL-C and TG with the tendency of FMtrunk/FMlegs to show the strongest correlations. For %FM and FMtrunk/FMlegs in both sexes, odds ratios (ORs) of the third tertiles with respect to the first tertiles increased for LDL-C elevation, TG elevation and dyslipidemia. In males, ORs of the third tertiles of WC were significantly high for LDL-C elevation and dyslipidemia whereas those of WHR were high for TG elevation and dyslipidemia. ORs of the third tertiles of WC and WHR were significantly high for TG elevation in females. BMI was not associated with the risk of abnormal lipid levels. ORs for hypertension showed significant increases in none of the variables of obesity.CONCLUSIONS: Excess accumulation of FM, especially to the upper body, was related to dyslipidemia in normal-weight subjects. Simple anthropometric variables, WC and WHR, may be useful for screening and management of dyslipidemia in these subjects.

Bezold-Jarisch-like reflex during Brockenbrough's procedure for radiofrequency catheter ablation of focal left atrial fibrillation: Report of two cases

Brockenbroughs puncture technique has been widely conducted in the electrophysiologic laboratory. We report here two cases exhibiting a rare complication of this procedure, which arose during the conduct of catheter ablation using radiofrequency energy delivered to the pulmonary vein for the treatment of focal left atrial fibrillation. These cases exhibited marked sinus bradycardia and profound hypotension, suggestive of a Bezold-Jarisch-like reflex, observed immediately after Brockenbroughs procedure but before radiofrequency application. ST elevation in the inferior leads was also observed in spite of normal coronary angiograms. This unanticipated transient complication was treated by intravenous administration of atropine, which had no influence on the ablation procedure or prognosis. This is speculated to be attributable to the elevation of vagal tone caused by the mechanical effects of transseptal puncture on the interatrial vagal network.

Quantitative correlation between cardiovascular and plasma epinephrine response to mental stress

SummaryTo investigate the quantitative correlations between cardiovascular and endogenous catecholamine response to mental stress, we gave a mental arithmetic test to 20 young healthy men. A direct and non-invasive haemodynamic measurement was performed by serial M-mode echocardiography. Heart rate, blood pressure, cardiac output, stroke volume, ejection fraction, left ventricular end-systolic pressure-volume ratio and plasma epinephrine increased over the baseline period during the test. The peripheral resistance and left ventricular end-systolic volume decreased, whereas left ventricular end-diastolic volume and plasma norepinephrine were unaltered. Furthermore, the degree of change in each haemodynamic parameter showing significant reaction, was well correlated with that of the increase in plasma epinephrine. The data suggest that acute mental stress induces endogenous epinephrine secretion resulting in aβ-adrenergic activated state in the cardiovascular system, namely, positive chronotropism, positive inotropism and vasodilatation.

Frequency of valvular regurgitation by color Doppler echocardiography in systemic lupus erythematosus

Abstract We studied valvular regurgitation in patients with systemic lupus erythematosus (SLE) by color Doppler echocardiography. Because valvular regurgitation occurs frequently in normal subjects, 1,2 we matched the patients by age with a control group. Furthermore, the same person examined both patients and normal subjects using the same Doppler echocardiographic apparatus.