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Biomedical subjects

M S Chang

Publications and source records attributed to M S Chang.

At least 253 records · Page 14Linked to original sources
PubMed1995

Restriction fragment length polymorphisms of apolipoprotein B gene in Chinese population with coronary heart disease.

Three restriction fragment length polymorphisms (RFLPs), EcoRI (R), Xbal (X), and Mspl (M) of the apolipoprotein (apo)B gene, were studied to determine their distribution frequencies and influence on the lipid profiles in 148 Chinese patients with documented coronary heart disease (CHD) and in 153 healthy subjects. The plasma concentrations of cholesterol and apoB showed no difference between the CHD patients and controls. However, CHD patients had significantly higher concentrations of low-density lipoprotein cholesterol and triglyceride and lower concentrations of high-density lipoprotein cholesterol than the controls. The frequencies of these three apoB RFLPs did not differ between the CHD patients and controls. Compared with South Asians and Caucasians, the Chinese in Taiwan showed a much lower frequency of R-, X+, and M- alleles. There was no evidence of an association between lipid profiles and RFLPs in either CHD patients or controls. The weak association of EcoRI, Xbal, and Mspl polymorphisms of the apoB gene with CHD indicates that the three RFLPs cannot be used as a predictor for the risk of CHD in the Chinese population.

Aged↗
PubMed1995

Short-term and long-term effects of benazepril in mild to moderate hypertensives.

BACKGROUND: Benazepril hydrochloride is a non-sulfhydryl-containing, angiotensin-converting enzyme (ACE) inhibitor. The short-term and long-term antihypertensive effects of benazepril remain to be established in Chinese. METHODS: Hypertensive subjects with diastolic blood pressure 95-110 mmHg, after two week placebo run-in first, entered a four-week double-blind phase with treatment of benazepril 10 mg once daily or captopril 25 mg three times daily, then received one-year open treatment of benazepril 10 mg daily with or without diuretics. Ambulatory blood pressure monitoring was performed at the end of placebo run-in, after four-week double-blind phase, and after one-year open treatment. RESULTS: Of the 75 subjects (41 male, 34 female, mean age 57 +/- 12 years, range 34-88 years) who completed the double-blind phase, 42 subjects finished the one-year extension phase. Reasons for withdrawal from the study included irritable cough (16, 21%), hypotension (1, 1%), and poor compliance (16, 21%). During the short-term double-blind phase, benazepril reduced clinic and mean 24-h ambulatory blood pressure by -21/-10 mmHg and by -17/-10 mmHg respectively, and captopril by -21/-13 mmHg and by -17/-10 mmHg respectively. After one-year open treatment by benazepril for the 42 subjects, the one-year average clinic blood pressure was 134/88 mmHg (155/104 mmHg at entry and 135/93 mmHg at the end of the double-blind phase), and the mean 24-h ambulatory blood pressure was 137/87 mmHg (149/95 mmHg at entry and 132/84 mmHg at the end of the double-blind phase). CONCLUSIONS: The antihypertensive effect of benazepril 10 mg daily with or without diuretics is not significantly different from that of captopril 75 mg daily in the short-term and can reasonably be maintained for one year.

Adult↗
PubMed1995

Assessment of heart wall motion: modified spatial modulation of magnetization for MR imaging.

This paper reports a new noninvasive method for detecting a regional myocardial infarction. The method consists of superimposing a magnetization grid onto different image planes of the human heart. In this study the spatial modulation of magnetization (SPAMM) in magnetic resonance imaging was modified to accommodate the use of a conventional clinical magnet. The percentages of circumferential shortening (PCS) and the percentages of wall thickening (PWT) during a cardiac cycle were estimated by measuring the amount of deformation of each grid from the end of the diastole to the end of the systole. A small data base was established on 10 subjects (6 normal volunteers and 4 patients). Patients with regional myocardial infarction, when monitored by the modified SPAMM investigation, showed smaller values of PCS and PWT in the areas where myocardial infarction was diagnosed by catheterization. The amount in decrement was directly proportional to the severity of the regional lesions.

Aged↗
PubMed1995

An appraisal of dipyridamole thallium imaging-detected ischemia in Chinese following acute myocardial infarction.

BACKGROUND: The detection of objective myocardial ischemia is an important work-up of risk stratification for survivors of acute myocardial infarction (MI). Intravenous dipyridamole thallium scintigraphy was used to identify the prevalence and prognostic value of silent myocardial ischemia (SI) at the early stage in patients after MI. METHODS: Ninety patients (male/female = 87/3; aged from 36 to 70 years) who succumbed to an episode of MI was recruited in this prospective study. Thallium imaging with reversible or combined defect was defined as presence of SI (Group I), while those with fixed defects or normal images were defined as absence of SI (Group II). Correlation between the patterns of thallium images for postinfarct ischemia and the angiographic lesions was investigated. Also, versatile clinical variables and indexes of adverse cardiac events: unstable angina, CHF, reinfarction, ventricular tachyarrhythmia and sudden death, were evaluated for their influence on patients' prognosis. The average follow-up was 11.6 months. RESULTS: There were 61 patients in the Group I as compared with 29 patients in the Group II. The difference of Killip functional classification between Group I and Group II patients was not significant (1.33 +/- 0.72 versus 1.07 +/- 0.59). Adverse cardiac event occurred in 30% (27/90) of the patients during follow-up. Cardiac death occurred in 6 cases (7%) and were distributed evenly (3 versus 3) in both groups. Group I patients showed a higher number of nonfatal reinfarctions (8 versus 5) and had more cases of percutaneous coronary angioplasty (11 versus 8) than Group II patients. Only two cases in Group I underwent bypass graft surgery. There was no statistic difference among four patterns of thallium image in the cumulative event-free survival curve. Prior history of CHF, prior MI and higher score index of proximal arterial stenosis were the three significant prognostic predictors for late cardiac events. CONCLUSIONS: Dipyridamole thallium imaging-detected SI was frequently seen in the Chinese patients following AMI. It was less valuable than prior histories of CHF, prior MI and higher index of proximal arterial stenosis scores in predicting the short-term unfavorable cardiac events in these patients. A large scale analysis and longer follow-up might be required to more accurately determine the role of this exam for the Chinese victims of myocardial infarction.

Adult↗
PubMed1995

Malaria and filariasis transmission in a village/forest setting in Baram District, Sarawak, Malaysia.

Entomological investigations on malaria and bancroftian filariasis transmission were carried out in the endemic area of Baram District, Sarawak. The Anopheles composition, survival and infection rates of malaria and filariasis were compared in the village and 0.5 km from the village ecotype, in forested areas. Anopheles leucosphyrus, An. barbirostris and An. donaldi are the vectors for malaria and bancroftian filariasis in both ecotypes. Biting and infection rates vary, but An. leucosphyrus differed with a peak around midnight in the forested area and soon after dusk in the village setting. The parous rate of An. leucosphyrus was significantly higher in the forest ecotype (P < 0.0001); however, the proportion of 3-parous and older was not overall higher in the forest ecotype (P = 0.68). The entomological inoculation of malaria parasites by An. leucosphyrus was comparatively higher in the forested areas (P > 0.5). The implications of malaria and filariasis transmission in the forested areas in Baram District are discussed.

Animals↗
PubMed1995

Clinical application of coronary angioscopic examination.

BACKGROUND: The coronary artery is examined with angioscopy in addition to coronary arteriogram to evaluate the potential clinical benefit of angioscopy. Changes in the coronary artery can be visualized which might not have been recognized before. METHODS: Coronary angioscopy was applied with Inoue coronary angioscope system, in cases with coronary artery disease. In case of angioplasty, a similar procedure was repeated after intervention. RESULTS: Twenty-one cases of coronary artery disease were examined with angioscopy. Successful visualization was obtained in 15 of them, with the rate to be 71.7%. The coronary angioscopy provided useful information about the coronary tree such as severity of atherosclerosis and integrity of endothelium and intraluminal thrombosis. Angioscopic change was even more remarkable after angioplastic intervention. Almost all cases had intimal abrasion. Damage to atheroma was observed in 77% of the cases, 38.5% had an intimal flap on dilatation site, and more thrombi were observed. CONCLUSIONS: Coronary angioscopic examination is valuable in the observation of coronary atherosclerosis and is especially helpful to evaluate cases of coronary angioplasty and to survey the results of therapy and severity of damage in the management of coronary artery stenosis.

Aged↗
PubMed1995

Spontaneous rupture of hepatobiliary cystadenoma: a case report.

Hepatobiliary cystadenoma is a rare hepatic neoplasm which has a high tendency to recur and has malignant potential. We review the literature and report a case of intrahepatic cystadenoma presenting with abdominal pain and ascites following spontaneous rupture. Complete excision of the tumor offers the best chance of cure and avoids recurrence, secondary infection or malignant change.

Adenoma, Bile Duct↗
PubMed1995

Reappraisal of cardiac murmurs related to aortic regurgitation.

BACKGROUND: With the advent of color Doppler echocardiography, which can detect even a trivial aortic regurgitation (AR), the spectrum of the audible cardiac murmurs caused by AR which presents specific and characteristic findings should receive further refinement. METHODS: Twenty-eight subjects with isolated AR (21 male and 7 female, mean age 61 +/- 41 yrs) diagnosed by colour Doppler echocardiography (15 mild, 6 moderate, and 7 severe by Nanda's criteria) and 8 normal controls (5 male and 3 female, mean age 38 +/- 15 yrs) were randomly invited for a physical examination to evaluate the systolic and diastolic murmurs in four auscultation areas by two experienced cardiologists who were blind to the clinical profile of each patient. Subsequently, a complete and comprehensive echocardiographic examination was performed to measure the transaortic peak velocity and time velocity integral, aortic root diameter, stroke volume, peak diastolic velocity and pressure half time of the AR jet, fractional shortening, and left ventricular systolic and diastolic internal dimensions. RESULTS: Systolic murmur was present in 62.5%, 66.7%, 100% and 100% of subjects with no, mild, moderate and severe AR, respectively. The corresponding numbers for diastolic murmur were 12.5%, 13.3%, 100% and 100% in subjects with no, mild, moderate and severe AR, respectively. The corresponding numbers for diastolic murmur were 12.5%, 13.3%, 100% and 100%. Multivariate analyses revealed that only the high peak aortic flow velocity was a significant determinant of systolic murmur. High grade AR, low diastolic blood pressure, high peak velocity of the AR jet and high systolic blood pressure were significant determinants of diastolic murmur. CONCLUSIONS: Both systolic and diastolic murmurs can be heard in most patients with moderate to severe AR. In contrast, a large proportion of subjects with mild AR have systolic murmur alone.

Adult↗
PubMed1994

Cloning and characterization of the human neutrophil-activating peptide (ENA-78) gene.

The neutrophil-activating peptide (ENA-78) is an inflammatory chemokine which is produced concomitantly with interleukin-8 (IL-8) in response to stimulation with either interleukin-1 (IL-1 beta) or tumor necrosis factor-alpha (TNF-alpha). We have identified a full-length ENA-78 cDNA and isolated its genomic clone. The gene was found to consist of four exons and three introns and its structure resembles the IL-8 gene. The human ENA-78 gene was mapped to chromosome 4q13-q21, the same locus as several other inflammatory cytokine genes. The transcription initiation site was mapped to a position 96 base pairs (bp) upstream from the translation initiation site. A fusion gene containing 125 bp upstream of exon 1 linked to a luciferase reporter gene was expressed in the human embryonic 293 cell line. The expression of the reporter gene was induced by TNF-alpha, IL-1 beta, or phorbol 12-myristate 13-acetate. The 125-bp promoter region contained the cis-regulatory elements for enhancer binding protein-like factor (C/EBP) and the nuclear factor (NF-kappa B). Transfection of 293 cells with deletion mutants demonstrated that the NF-kappa B element, but not the C/EBP site, is sufficient for expression and induction by either TNF-alpha or IL-1 beta. In contrast, the IL-8 gene requires both elements. This report demonstrates that ENA-78 and IL-8 genes shared great similarity in genomic structure and chromosome location. However, these two genes may be regulated by distinct mechanisms.

Amino Acid Sequence↗
PubMed1994

Identification and cloning of a megakaryocyte growth and development factor that is a ligand for the cytokine receptor Mpl.

A novel megakaryocyte growth and development factor (MGDF) has been identified in aplastic canine plasma, and its cDNAs have been cloned from canine, murine, and human sources. Purified canine MGDF isolated by procedures involving MpI receptor affinity chromatography exists in at least two forms, with apparent molecular masses of 25 kDa and 31 kDa, that share the N-terminal amino acid sequence APP-ACDPRLLNKMLRDSHVLH. Human, dog, and mouse cDNAs for MGDF are highly conserved and encode open reading frames for proteins of 353, 352, and 356 amino acids, respectively, including predicted signal peptides. Canine MGDF and recombinant human MGDF support the development of megakaryocytes from human CD34+ progenitor cell populations in liquid culture and promote the survival of a factor-dependent murine cell line (32D) engineered to express MpI. These biological activities are blocked by the soluble extracellular domain of MpI. These data demonstrate that MGDF is a novel cytokine that regulates megakaryocyte development and is a ligand for the MPI receptor.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of the human interleukin-9 receptor gene.

To better understand the regulation of interleukin-9 (IL-9) receptor expression, we have isolated the genomic clone of the human IL-9 receptor based on its sequence homology with a human IL-9 receptor cDNA isolated from the human megakaryocyte cell line UT-7. The entire genomic structure has been determined. The human IL-9 receptor gene consists of 10 exons spread over approximately 13.7 kb of DNA. The nucleotide sequence of the coding region from the genomic DNA is identical to our cDNA clone. Several blocks of transcriptional control sequence have been identified at the 5' noncoding region of the IL-9 receptor gene that may play an important role in the regulation of the IL-9 receptor gene. A fusion gene containing 659 bp of human IL-9 receptor 5' noncoding region linked to the firefly luciferase gene directed expression of luciferase activity in human embryonic kidney 293 cell line, but not in the mouse fibroblast cell line NIH3T3 cells.

Amino Acid Sequence↗
PubMed1994

Accessory pathway and atrioventricular node reentrant tachycardia in elderly patients: clinical features, electrophysiologic characteristics and results of radiofrequency ablation.

OBJECTIVES: This study was designed to evaluate the clinical features, electrophysiologic characteristics and results of radiofrequency ablation in elderly patients with accessory atrioventricular (AV) pathways or AV node reentrant tachycardia. BACKGROUND: Radiofrequency ablation in elderly patients with paroxysmal supraventricular tachycardia has not been well described, and comparative study between elderly and younger patients is limited. METHODS: Electrophysiologic studies and radiofrequency ablation were performed in 92 elderly patients (45 with an accessory pathway, 47 with AV node reentrant tachycardia). RESULTS: The elderly patients had poorer electrophysiologic properties in accessory pathways and dual AV node pathways than those of younger patients. The success rate of radiofrequency ablation was similar in elderly and younger patients. However, elderly patients had more complications (14%) in left-sided accessory pathways. CONCLUSIONS: Radiofrequency ablation in elderly patients with supraventricular tachycardia was effective. However, it must be performed cautiously in those patients with left-sided accessory pathways.

Adult↗
PubMed1994

No evidence for linkage of long QT syndrome and chromosome 11p15.5 markers in a Chinese family: evidence for genetic heterogeneity.

Recently the defective gene locus in seven Caucasian families with the Romano-Ward form of long QT syndrome (LQT) has been mapped to chromosome 11p. To understand the molecular basis of LQT in Chinese, a three-generation family was investigated. Fourteen family members were studied and five individuals were diagnosed to be affected, according to electrocardiographic criteria. Two genomic DNA probes (c-Ha-ras-3'-HVR and insulin-5'-HVR) and one tetranucleotide repeat polymorphism (THZ) derived from chromosome 11p15.5 loci and previously demonstrated to be closely linked to LQT were used as probes to analyze this family. A lod score of less than -2 was noted for all three polymorphisms. Our data show that there was no evidence of linkage between these three loci and the gene for LQT in this studied family. We believe that this result provides additional evidence for genetic heterogeneity of LQT.

Adolescent↗
PubMed1994

Vasodilator therapy in chronic asymptomatic aortic regurgitation: enalapril versus hydralazine therapy.

OBJECTIVES: This study attempted to evaluate the long-term efficacy of enalapril versus hydralazine therapy on left ventricular volume, mass and function as well as on the renin-angiotensin system in chronic asymptomatic aortic regurgitation. BACKGROUND: We tested the hypothesis that early administration of a vasodilator drug might be able to reduce left ventricular dilation and mass expansion. Because the renin-angiotensin system may be activated in chronic aortic regurgitation, early enalapril therapy might be beneficial. METHODS: Between 1990 and 1993, 76 asymptomatic nonrheumatic patients with mild to severe chronic aortic regurgitation were enrolled in a randomized, double-blind trial comparing enalapril with hydralazine. All patients underwent serial noninvasive studies. Seventy patients completed the 12-month follow-up. RESULTS: At 1 year, patients receiving enalapril had a significant reduction in left ventricular end-diastolic and end-systolic volume indexes (124 +/- 15 vs. 108 +/- 17 ml/m2, p < 0.01; 50 +/- 12 vs. 40 +/- 14 ml/m2, p < 0.01, respectively) and mass index (131 +/- 16 vs. 113 +/- 19 g/m2, p < 0.01), whereas hydralazine therapy showed no significant changes. Both regimens not only had a significant reduction in left ventricular mean wall stress but also had a mild increase in exercise duration. Only enalapril therapy achieved a significant inhibition of the renin-angiotensin system, in contrast to hydralazine therapy. Moreover, the multiple r2 value from the analysis for end-diastolic volume index using the two variables of age and treatment drugs was 72.1% (p < 0.01). CONCLUSIONS: Both regimens decrease left ventricular mean wall stress. Enalapril therapy achieves significant left ventricular mass regression, left ventricular end-diastolic and end-systolic volume index reduction and renin-angiotensin system suppression. These findings suggest that early unloading enalapril therapy has the potential to favorably influence the natural history of chronic aortic regurgitation.

Aged↗
PubMed1994

Prevention and treatment of ocular inflammation with a new class of non-steroidal anti-inflammatory agents.

New non-steroidal anti-inflammatory agents (NSAIAs) were tested on lens protein-, endotoxin- and interleukin-1-induced ocular inflammation. It was found that most NSAIAs, including REV 5901, mefenamic acid, indomethacin, CK-17 and CK-102, inhibited lens protein-induced inflammation. Endotoxin induced inflammation indirectly through the release of IL-1 which was inhibited by fewer agents, including CK-17, CK-102 and prednisolone. However, the direct effect of IL-1 can only be suppressed by CK-17 and prednisolone. Therefore, CK-17 could become an important NSAIA which acts similarly to corticosteroids yet produces no steroidal side effects. CK-17 was different from most NSAIAs as it affected little, if any, arachidonate metabolism. Most importantly, CK-17 was found to be 2-fold more potent than prednisolone in inhibiting IL-1-induced uveitis, while no side effects were noted at doses tested to date.

Animals↗