Browsing by Author "Hsu K.-L."

We studied whether the 27 base pair (bp) tandem repeat polymorphism in intron 4 of the endothelial nitric oxide synthase (eNOS) gene was associated with coronary artery disease (CAD) in a hospital-based Taiwanese population. We included 219 consecutive patients who underwent coronary angiography at our institution. Two alleles, containing 4 (eNOS4a) and 5 repeats (eNOS4b), were identified after polymerase chain reaction amplifying intron 4 of the eNOS gene. The genotype frequencies for eNOS4b/b, eNOS4a/b and eNOS4a/a were 77.9, 21.5 and 0.6% in CAD subjects, and 80, 20 and 0% in control subjects (Fisher's exact test, p = 0.90), respectively. The odds ratio (OR) for CAD in patients with at least one eNOSa allele was 1.2 (0.5-2.9) after adjustment for classical CAD risk factors. The eNOS4a allele was not associated with the severity of CAD (Fisher's exact test, p = 0.90) and the occurrence of acute myocardial infarction (AMI) or unstable angina (adjusted OR 0.6, 0.3-1.6) in patients with CAD. In conclusion, the 27-bp repeat polymorphism of the eNOS gene was not associated with CAD and the occurrence of AMI or unstable angina in a hospital-based Taiwanese population. Copyright ? 2002 S. Karger AG, Basel.

The central neural mechanisms of circadian rhythm are well known in animal models but less so in humans. In this study we looked for correlations between abnormalities of circadian rhythm and the sites of stroke, with the aim of identifying the location regulating the circadian rhythm in humans. We investigated the circadian profiles of arterial pressure in 100 stroke patients by ambulatory blood pressure monitoring within 2 days after their first stroke. Patients also underwent brain computed tomography and measurements of plasma norepinephrine and adrenal hormones. A total of 52 patients (group A) had abnormal patterns of circadian blood pressure rhythm while 48 patients had normal patterns (group N). The risk of an abnormal 24-hour blood pressure pattern was strongly inversely correlated with the distance between the lesion and the hypothalamus. There was also a close positive correlation between the distance from the lesion to the hypothalamus and the circadian indices of arterial blood pressure (systolic and diastolic pressures) in both groups. Abnormal circadian changes in adrenal hormones were found in 30 of 52 patients in group A, and in nine of 48 patients in group N. Apparently, the circadian rhythm of blood pressure is modulated mainly by direct neural effects and partly by the hormonal effects of the hypothalamus and its associated neural pathways. Individualized antihypertensive treatment and additional monitoring for possible cardiac events should be performed for those at a high risk of autonomic dysfunction.

To evaluate the accuracy of various types of wall motion response during dobutamine echocardiography (DE) in predicting functional recovery after revascularization, we studied 30 patients with stable coronary disease and left ventricular dysfunction by simultaneous DE and 201Tl reinjection SPECT. Among 480 segments (16 segments/patient), 199 had abnormal wall motion at baseline and 167 were revascularized. The predictive value for recovery of function was 72% for a biphasic response, 61% for sustained improvement, 77% for worsening, and 27% for no change (p < 0.01 vs. each). Biphasic response had a sensitivity of 40% and specificity of 85%. Combining biphasic, sustained improvement and worsening responses, the sensitivity, specificity and accuracy were 76%, 65% and 71%, respectively. For 201Tl SPECT, they were 90%, 65% and 78%, respectively. Thus, a biphasic response alone is of low sensitivity. Combination of biphasic, sustained improvement and worsening responses gives an accuracy rate comparable to that of 201Tl reinjection SPECT in assessing functional recovery. ? 2001 World Federation for Ultrasound in Medicine & Biology.

1. In recent studies, aminoguanidine (AG), an inhibitor of advanced glycation endproducts, has been identified as a prominent agent that can prevent the age-related aortic stiffening and cardiac hypertrophy. The aim of this study was to determine whether AG had effects on the left ventricular (LV)-arterial coupling in aged Fisher 344 rats in terms of the ventricular and arterial chamber properties. 2. Normotensive rats were treated from 18 to 24 months with AG (1 gl -1 in drinking water) and compared with a control group. LV pressure and ascending aortic flow signals were recorded to construct the ventricular and arterial end-systolic pressure-stroke volume relationships to calculate LV end-systolic elastance (E es) and effective arterial volume elastance (E a), respectively. The optimal afterload (Q load) determined by the ratio of E a to E es was used to measure the efficiency of mechanical energy transferred from the left ventricle to the arterial system. 3. In comparison with the 6-month-old rats, the 24-month-old animals had decreased E es, at 567.4±26.7 vs 639.0±20.7 mmHg ml -1, decreased E a, at 411.5±18.6 vs 577.9±15.7 mmHg ml -1, and decreased Q load, at 0.9428±0.0024 vs 0.9962±0.0014. 4. Treatment with AG for 6 months did not significantly affect E es; however, when normalized to LV weight (i.e., E esn = E es/LV weight), E esn showed a significant rise of 22.8%, suggesting that AG may retard the aging process on the intrinsic contractility of the left ventricle. On the other hand, the decrease in E a in aging rats was prevented by AG, as reflected in the increase of 19.7% in this variable (P<0.05). The 24-month-old treated rats also exhibited a significant rise of 21.6% in E a/E es, causing an increase of 5.2% in Q load (P<0.05). 5. We conclude that in healthy older Fisher 344 rats without diabetes, long-term treatment with AG may improve both the arterial and ventricular function and optimize the matching condition for the left ventricular-arterial coupling.

1 The formation of advanced glycation endproducts (AGEs) on collagen within the arterial wall may be responsible for the development of diabetic vascular injury. This study was to examine the role of aminoguanidine (AG), an inhibitor of AGEs formation, in the prevention of arterial stiffening and cardiac hypertrophy in streptozotocin (STZ) induced diabetes in rats. 2 Diabetes was induced in animals by a single tail vein injection with 65 mg kg -1 STZ. After confirmation of the development of hyperglycemia (2 days later), rats were treated for 8 weeks with AG (daily peritoneal injections of 50 mg kg -1) and compared with the age-matched untreated diabetic controls. 3 After exposure to AG, the STZ-diabetic rats showed no alterations in cardiac output, aortic pressure profiles, total peripheral resistance, and aortic characteristic impedance. 4 By contrast, treatment of this experimental diabetes with AG resulted in a significant increase in wave transit time (τ), from 20.4 ± 0.6 to 24.7 ± 0.5 ms (P < 0.05) and a decrease in wave reflection factor (R f), from 0.78 ± 0.04 to 0.53 ± 0.02 (P < 0.05). The decreased R f associated with the increased τ suggest that AG may retard the diabetes-induced augmentation in systolic load of the left ventricle coupled to its arterial system. 5 Meanwhile, the diminished ratio of left ventricular weight to body weight suggests that prevention of the diabetes-related cardiac hypertrophy by AG may correspond to the drug-induced decline in aortic stiffening. 6 Glycation-derived modification on aortic collagen was also found to be enhanced in rats with diabetes (+ 65.3%, P < 0.05) and the advanced glycation process was retarded by AG treatment. 7 We conclude that long-term administration of AG to the STZ-treated rats imparts significant protection against the diabetes-derived deterioration in vascular dynamics, at least partly through inhibition of the AGEs accumulation on collagen in the arterial wall. ? 2006 Nature Publishing Group All rights reserved.

Amiodarone-related pneumonitis is a potentially limiting factor for amiodarone usage. However, it is believed that amiodarone-related pneumonitis is unlikely to occur during low-dose and short courses of therapy. We report three patients who received low-dose amiodarone, 200 mg/day, for an average of 6.6 months and who developed amiodarone-related pneumonitis. All patients were male with age of 75, 93 and 85, respectively, and had the habit of cigarette smoking. The initial presentation was dyspnea without symptoms and signs of heart failure. Their chest radiographs showed diffuse interstitial pneumonitis pattern and chest computed tomography scan also confirmed interstitial pneumonitis. Treatment included cessation of amiodarone and corticosteroid usage. All patients improved symptomatically by early detection and early treatment. This case report implies that old age and possible pre-existing pulmonary abnormalities caused by smoking could be associated with amiodarone-related pulmonary toxicity. Clinicians must remain alert to detect amiodarone-related pneumonitis even under low dosage and short duration of amiodarone usage. Immediate withdrawal of amiodarone and prompt steroid therapy will ensure full recovery. ? 2007 Elsevier & Formosan Medical Association.

Nine-link type double-toggle mold/die clamping mechanisms are widely used in modern injection molding machines and die casting machines in order to provide sufficient mold/die clamping force for counteracting the pressure occurred inside molds/dies. In this paper, the analysis and experimental evaluation of mechanical errors in nine-link type double-toggle mold/die clamping mechanisms are presented. The kinematic error equations of the output link (i.e., the moving platen) caused by dimensional errors (or tolerances) of link members are derived analytically through the concept of tolerance sensitivity analysis. Evaluation indices based on the asymmetry of the mold/die clamping mechanism caused by mechanical errors are established. A case study is then given to demonstrate the derived analytical equations and the established evaluation indices. Subsequently, a prototype for performing the experimental evaluation is conceptually designed and was actually constructed. Experiments were conducted for evaluating the quantitative influence of mechanical errors on the operating performance of the constructed mold/die clamping mechanism. According to the experimental results, response surface modelling for benefiting the constructed mold/die clamping mechanism with better operating performance could be performed. The presented research results will be helpful in the tolerance analysis and mechanical error detection of nine-link type double-toggle mold/die clamping mechanisms. ? 2021 by the authors.

There are many reports demonstrating the association of renin-angiotensin system gene polymorphisms with hypertension in different populations. In the present study, we used haplotype analyses of the angiotensinogen gene with a new permutation-based hypothesis testing method to determine the association between multilocus angiotensinogen gene polymorphisms and hypertension in a relatively homogeneous Taiwanese population. We also genotyped angiotensin-converting enzyme gene insertion/deletion polymorphism and angiotensin II type 1-receptor gene A1166C polymorphism to detect epistatic gene-gene interactions. There were 408 patients with hypertension (hypertensives) and 286 controls. The angiotensinogen gene haplotype frequencies were significantly different between hypertensives and controls, and this finding was only present in subjects with angiotensin-converting enzyme gene II genotypes when the analysis was stratified by genotype of this polymorphism. In addition, the angiotensinogen gene haplotype structure of hypertensives was more heterogeneous than that of controls. Our results showed that angiotensinogen gene haplotypes were associated with hypertension and might act synergistically with I allele of the angiotensin-converting enzyme gene.

Background: Our team previously demonstrated arterial stiffening and cardiac hypertrophy in type 2 diabetic rats at 8 but not 4 weeks after being administered streptozotocin (STZ) and nicotinamide (NA). The present study focused on investigating the effects of type 2 diabetes on cardiac autonomic nerve function in the STZ- and NA-treated animals, using modern spectral estimation technique. Design: An autoregressive process was performed to each detrended signal of heart rate and systolic blood pressure measured in the 4- and 8-week STZ-NA rats with anaesthesia. The power of low-frequency and high-frequency oscillations was automatically quantified with each spectral peak by computing the residuals. The closed-loop baroreflex gain was estimated using the square root of the ratio between heart rate and systolic blood pressure powers in the low-frequency band. Results: Compared with the age-matched controls, both the 4- and 8-week STZ-NA diabetic rats had significantly decreased low-frequency oscillations of heart rate but not systolic blood pressure variability, showing a decline in baroreflex gain (0.451 ± 0.060 and 0.484 ± 0.056 vs. 1.196 ± 0.064 ms mmHg-1, P < 0.05). On the other hand, the low frequency-high frequency power ratio of the heart period was also diminished in the two diabetic groups, indicating a shift in sympatho-vagal balance of the heart control (0.472 ± 0.109 and 0.504 ± 0.090 vs. 1.857 ± 0.336, P < 0.05). Conclusions: The cardiac autonomic dysfunction in the absence of any significant changes in vascular dynamics, 4 but not 8 weeks after induction of type 2 diabetes, suggests that the diabetic autonomic neuropathy may precede arterial stiffening and cardiac hypertrophy in the STZ- and NA-treated rats. ? 2008 The Authors.

Background: Balloon valvuloplasty has been used for congenital valvular pulmonary stenosis (PS) in pediatric patients as a conventional treatment. The purpose of this study was to further investigate the safety, immediate and long-term results of balloon valvuloplasty in adults with congenital valvular pulmonary stenosis. Method and Result: We analyzed hemodynamic data of 12 patients who underwent balloon pulmonary valvuloplasty (ages 20-80, mean 41 years). Double-balloon technique was used in 8 patients and single-balloon technique in 4 patients (including 1 case with Inoue balloon). Right ventricle systolic pressure and pulmonary valve peak-to-peak systolic pressure gradient decreased from 101.4 ± 35.0 to 48.8 ± 17.7 mmHg (p < 0.001) and 85.3 ± 37.3 to 29.9 ± 20.0 mmHg (p < 0.001), respectively. Ten patients underwent transthoracic Doppler echocardiography follow-up 2-184 months (mean 68.6 months) after pulmonary balloon valvuloplasty, and peak transvalvular systolic pressure gradient further decreased to 15.1 ± 11.9 mmHg (p = 0.001). All patients had symptomatic improvement, and no major complication or mortality was noted. Conclusion: Balloon pulmonary valvuloplasty is a safe and effective treatment for adult patients with congenital valvular PS. In our experience, even elderly patients (up to 80 years old) had satisfactory result.