Abstract-Arterial elasticity is determined by structural characteristics of the artery wall and by vascular smooth muscle tone. The identity of endogenous vasoactive substances that regulate elasticity has not been defined in humans. We hypothesized that NO, a vasodilator released constitutively by the endothelium, augments arterial elasticity. Seven healthy young men were studied. A 20-MHz intravascular ultrasound catheter was introduced through an arterial sheath to measure brachial artery cross-sectional area, wall thickness, and intra-arterial pressure. After control was established, indices of elasticity (pressure-area relationship, instantaneous compliance, and stress-strain, pressure-incremental elastic modulus (E inc ), and pressure-pulse wave velocity relationships) were examined over 0 to 100 mm Hg transmural pressure obtained by inflation of an external cuff. Thereafter, the basal production of endothelium-derived NO was inhibited by N G -monomethyl-L-arginine (L-NMMA) (4 and 8 mg/min). Finally, nitroglycerin (2.5 and 12.5 g/min), an exogenous donor of NO, was given to relax the vascular smooth muscle. Elasticity was measured under all of these conditions. L-NMMA (8 mg/min) decreased brachial artery area (Pϭ0.016) and compliance (PϽ0.0001) and increased E inc (PϽ0.01) and pulse wave velocity (PϽ0.0001). Nitroglycerin (12.5 g/min) increased brachial artery area (PϽ0.001) and compliance (PϽ0.001) and decreased pulse wave velocity (Pϭ0.02). NO, an endothelium-derived vasodilator, augments arterial elasticity in the human brachial artery. Loss of constitutively released NO associated with cardiovascular risk factors may adversely affect arterial elasticity in humans. Key Words: brachial artery Ⅲ elasticity Ⅲ human Ⅲ endothelium-derived relaxing factor E lasticity of large arteries absorbs the energy of the phasic stroke volume in systole and thereby dampens the arterial pressure wave during its propagation through the arterial tree. 1 The release of stored energy in diastole facilitates the continuous flow of blood to tissues. 2 Several indices of arterial elasticity have been used in clinical studies, including compliance, distensibility index, stress-strain relationships, Young's modulus, and pulse wave velocity. Arterial compliance refers to the relationship between arterial dimension and the distending pressure. An increase in compliance corresponds to a decrease in artery stiffness. Arterial compliance changes in a nonlinear fashion with blood pressure. It tends to be greater at lower blood pressures, and for this reason the distensibility index (change in volume/change in pressureϫbaseline volume) can lead to erroneous conclusions if the mean distending pressure is shifted by an intervention. Compliance curves and the incremental modulus (E inc ) can be used to assess elasticity independent of the blood pressure changes. Recently, a technique to assess arterial elasticity in humans with the use of intravascular ultrasound to measure arterial dimension and inflation of an external blood pressure cuff...

Diabetes is a complex and heterogeneous disease, making the prediction of the risks of diabetic complications challenging. Novel adult-onset diabetes subgroups have been studied using cluster analysis, but its application in East Asians remains unclear. We conducted a retrospective cohort study to elucidate the clinical utility of cluster-based subgroup analysis in the Japanese population. Cluster analysis based on anti-glutamate decarboxylase antibody (GAD antibody) levels, age at diagnosis, body mass index (BMI), hemoglobin A1c (A1c), and homeostatic model assessment 2 estimates of β-cell function and insulin resistance was performed in 1520 diabetic patients. The risk of developing diabetic complications was analyzed using Kaplan–Meier analysis and the Cox proportional hazards model. By cluster analysis, we identified five distinct subgroups of adult-onset diabetes in the Japanese population. The risk of diabetic complications varied greatly among the clusters. Patients with severe autoimmune diabetes or severe insulin deficiency diabetes were at an increased risk of diabetic retinopathy, and those with severe insulin resistant diabetes (SIRD) had the highest risk of developing diabetic kidney disease (DKD). After adjusting for uncorrectable and correctable risk factors, SIRD was found to be an independent risk factor for DKD. In conclusion, we identified five subgroups of adult-onset diabetes and the risk factors for diabetic complications in the Japanese population. This new classification system can be effective in predicting the risk of diabetic complications and for providing optimal treatment.

Titration of the duration of the ablation energy delivery while monitoring the ET could prevent periesophageal nerve injury due to the AF ablation, without decreasing the success rate of maintaining sinus rhythm.

The role of vertical larynx movement in vocal frequency (F0) change has attracted the attention of many researchers. Recently, Hirai, Honda, Fujimoto, and Shimada (1994) proposed a mechanism of F0 control by vertical larynx movement based on the measurement of magnetic resonance images (MRI). In F0 changes, the larynx moves vertically along the cervical spine, which displays anterior convexity (lordosis) at the level of the larynx. Therefore, the vertical larynx movement results in the rotation of the cricoid cartilage and vocal fold tension changes. The present study reexamines the above mechanism based on a qualitative analysis of midsagittal MRI data using three male subjects with evident cervical lordosis. Tracings of the jaw, hyoid bone, laryngeal cartilage, and cervical spine were compared in high and low F0 ranges. In the high F0 range, the hyoid bone moved horizontally while the larynx height remained relatively constant. In the low F0 range, the entire larynx moved vertically, and the cricoid cartilage rotated along the cervical lordosis. These results indicate that the vertical movement of the larynx comprises an effective F0 lowering mechanism, and suggest that the human morphologies of low larynx position and spinal curvature contribute to voluntary use of the vocal function.