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Biomedical subjects

H J Chang

Publications and source records attributed to H J Chang.

At least 37 records · Page 2Linked to original sources
PubMed1999

String-plucking as a mechanism of chordal rupture during balloon mitral valvuloplasty using inoue balloon catheter.

Percutaneous transvenous mitral commissurotomy using the Inoue technique was performed in a 59-year-old female with mitral stenosis and a severely calcified mitral leaflets. Although not entrapped in the subvalvular apparatus, the balloon catheter was deviated away from the mitral orifice-apex axis of the left ventricle during the inflation of the proximal balloon, which plucked and severed the chordae tendineae of the posterior mitral leaflet and resulted in severe mitral regurgitation.

Calcinosis↗
PubMed1999

Expression of foreign antigens on the surface of Escherichia coli by fusion to the outer membrane protein traT.

The traT gene is one of the F factor transfer genes and encodes an outer membrane protein which is involved in interactions between an Escherichia coli and its surroundings. This protein was altered so as to permit the expression of foreign proteins on the outer membrane of E. coli in this study. A 729-bp DNA fragment, including the leader and entire structural gene sequence of traT, was amplified and obtained by PCR. This sequence was then subcloned downstream of the tac promoter of pDR540, resulting in a TraT expression vector, pT2. Here, we report that the expression of TraT protein, fused either with a partial pre-S antigen of hepatitis B virus (60 and 98 amino acids, respectively) or with the snake venom rhodostomin (72 amino acids), was successfully achieved on the outer membrane of E. coli, using the pT2 plasmid. This result was demonstrated using dot blot and immunofluorescence analysis. This finding supports the notion that the pT2 plasmid can be used as an E. coli display system. This system can detect a foreign peptide of about 100 amino acid residues in length on the bacterial surface.

Bacterial Outer Membrane Proteins↗
PubMed1999

Papillary endothelial hyperplasia presenting as a chest wall neoplasm.

Soft tissue hematomas generally resolve but may persist and develop into slow-growing, organized masses. These chronic expanding hematomas are characterized by a pseudocapsule and a predominantly necrotic central cavity, with foci of newly formed capillaries. These have been called chronic expanding hematomas or Masson's papillary endothelial hyperplasia. These lesions can mimic vascular neoplasms and must be considered in the evaluation of expanding soft tissue vascular malformations.

Chronic Disease↗
PubMed1999

Mechanisms and clinical significance of transient atrioventricular block during dobutamine stress echocardiography.

OBJECTIVES: The purpose of this study was to investigate the possible mechanism and the clinical significance of transient atrioventricular block (AVB) during dobutamine stress echocardiography (DSE). BACKGROUND: Transient AVB occurs rarely during DSE; however, the mechanisms responsible for blocks are unclear. METHODS: A retrospective analysis of clinical, echocardiographic, catheterization, revascularization and head-up tilting test data was conducted in patients who developed transient AVB during DSE. RESULTS: A total of 302 patients with known or suspected coronary artery disease (CAD) underwent DSE before coronary angiography between November 1997 and August 1998. Transient AVB developed in 12 patients during the test. Mobitz I block was noted in six patients and Mobitz II block in the other six patients. Nine of these 12 patients were subsequently shown to have CAD and three had no significant coronary artery stenosis. Mobitz II block was observed only in patients with CAD, while Mobitz I block occurred in three patients with and three patients without CAD (p < 0.05). Eight of the nine patients with CAD underwent a successful coronary angioplasty with or without stenting and a repeat DSE revealed no recurrence of heart block except in one patient. Head-up tilting test in the 12 patients revealed a positive response in three of the nine patients with and all three patients without CAD. A negative head-up tilting test was likely to be observed in patients with, as compared with those without, CAD in this study population (p < 0.05). CONCLUSIONS: Transient AVB is not an infrequent manifestation during DSE. Both myocardial ischemia and neurally mediated vagal reflex may be responsible for this phenomenon. The development of Mobitz II block during DSE is indicative of the presence of CAD. A successful revascularization in patients with CAD who develop transient AVB may abolish this phenomenon.

Adult↗
PubMed1999

Antibiotic usage in primary care units in Taiwan.

To understand the situation of antibiotic usage in primary care units in Taiwan, we collected all prescriptions over a 1 week period during March 2 to March 7, 1992, December 2 to December 7, 1992, and January 14 to January 19, 1994 from out-patient clinics of public health stations located in various parts of Taiwan. In the first time period 60 health stations were sampled, 18,350 patient-visits made and 23,674 diagnoses recorded. In the second time period 168 health stations were sampled, 84,143 patient-visits made and 96,528 diagnoses recorded. In the third time period 173 health stations were sampled with 85,623 patient-visits and 105,132 diagnoses recorded. The percentages of total patient-visits that resulted in antibiotic treatment were 16.7, 13.5 and 12.4% in the three time periods, respectively. The patient group under the age of 11 received the highest percentage of antibiotic treatment. The percentage of patient-visits that resulted in treatment with two or more types of antibiotics decreased from 25.4% in March, 1992 to 13.2% in January, 1994. Common cold was the most frequent diagnosis in patients receiving antibiotic therapy during the three time periods and accounted for 36.9% of total antibiotic prescriptions. Of the patients with the diagnosis of common cold, 29.7% received antibiotic treatment, of whom the largest group were paediatric patients (< 16 years). Penicillins, macrolides and cephalosporins were the most commonly prescribed antibiotics and accounted for 34.0, 21.8 and 21.3% of all prescribed antibiotics in the three study periods.

Adolescent↗
PubMed1999

A Markov chain model to assess the efficacy of screening for non-insulin dependent diabetes mellitus (NIDDM).

BACKGROUND: The high prevalence and severe consequences of non-insulin dependent diabetes mellitus (NIDDM) in Taiwan calls for urgent measures to detect this disease in the asymptomatic phase. However, the efficacy of early detection of NIDDM is highly dependent on its natural history from the disease-free state, through the asymptomatic to the symptomatic phase and death from NIDDM or other causes. METHODS: In order to project the above progression, a five-state illness-and-death Markov chain model was proposed to estimate these transition parameters using data from two rounds of a blood sugar screening programme for NIDDM in Puli, in central Taiwan. RESULTS: Results showed that the annual incidence for asymptomatic NIDDM was 10.67 per 1000 (95% CI: 8.26-13.79) and the average duration between the asymptomatic and symptomatic phases (the sojourn time) was 8 years (95%CI: 5.74-11.29). The 10-year survival rate for asymptomatic NIDDM (79.35%) was better than that for symptomatic NIDDM (69.45%). Prediction of deaths from NIDDM was performed to assess how the efficacy of screening for NIDDM varied by different screening frequencies (annual, biennial, 4-yearly and the control group). Results indicated there is no substantial difference in mortality reduction from NIDDM among the annual, biennial and 4-yearly screening regimens. However, a 4-yearly screening regimen significantly reduced deaths from NIDDM by 40% (95% CI: 26-51%). CONCLUSIONS: A long sojourn time and the substantial reduction in mortality suggest that a 4-yearly screening regime for NIDDM would be most effective and feasible in Taiwan. The proposed five-state Markov chain model can be applied to other similar NIDDM screening projects.

Adolescent↗
PubMed1999

Gallstone formation and gallbladder mucosal changes in mice fed a lithogenic diet.

To investigate the pathologic change of gallbladder mucosa related to gallstone formation, 52 mice were fed a lithogenic diet containing 1% cholesterol and 0.5% cholic acid and we evaluated the sequential morphologic changes in the gallbladder from two days to 40 weeks. Cholesterol gallstones began to appear after two weeks and all the mice had gallstones after eight weeks. At two days, the mitotic index was at its highest. The gallbladder mucosa showed progressive hyperplastic change with earlier papillary projection of the folds and later inward proliferation. At the same time of stone formation, mucous cells forming glands appeared. Their histochemical profile of mucin was different from that of normal epithelium. Numbers of mucous cells increased gradually until 24 weeks but slightly decreased afterward. These results suggest hyperplasia and metaplasia are closely related to the gallstone formation. Hyperplasia is probably reactive to irritating effect of lithogenic bile or stone. Metaplasia and cholesterol gallstone may develop simultaneously, and act synergistically.

Animals↗
PubMed1999

Cognition and utilization of Papanicolaou testing after the implementation of National Health Insurance in rural Taiwan.

Previous reports have indicated that knowledge and utilization of Papanicolaou (Pap) testing in Taiwan are low, especially among residents of rural areas. However, those studies were conducted before the implementation of National Health Insurance (NHI), which now covers Pap testing. To assess the cognition and utilization of Pap testing after the implementation of NHI in 1995, 708 women aged 40 years or more were interviewed by the Yang-Ming Crusade in July 1997. Of these women, 276 (39%) had heard of the Pap test, 226 (32%) had had the test, and 156 (22%) had had the test in the last 3 years (1995-1997). Of those who had never had the Pap test before 1995, 17% underwent it for the first time after the implementation of NHI. In contrast to an earlier comparable study, the present study shows a significant increase in both the cognition and utilization rates of Pap testing (from 27% to 39%, and 18% to 32%, respectively) among women in rural areas after the test was covered by NHI. However, both knowledge and use of the test among older and lower-educated women are still low.

Adult↗
PubMed1999

Loss of heterozygosity in dysplasia and carcinoma of the gallbladder.

The loss or inactivation of genes at specific chromosomal loci is one of the important mechanisms during the tumor development in humans. To investigate the role of genetic alterations in the carcinogenesis of gallbladder carcinoma, 32 carcinoma cases and 11 dysplasia cases of gallbladder were analyzed for loss of heterozygosity (LOH) and microsatellite instability (MI) on chromosomal regions 3p, 5q, 8p, 9p, 13q, 17p, and 18q with 17 microsatellite markers. Loss of one allele was identified on chromosomes 5q (55%) and 17p (40%) in dysplasias and on chromosomes 3p (52%), 5q (66%), 9p (52%), and 17p (58%) in carcinomas. LOH on chromosomes 13q and 18q was frequent only in advanced stage (III and IV) carcinomas (40% and 31%, respectively). LOH on chromosome 17p was correlated with intranuclear p53 accumulation. LOH on multiple chromosomes was more frequent in advanced carcinomas with metastasis than in cases without metastasis (P < .05). A widespread MI was observed in only one case of carcinoma. We conclude that LOH on 5q is an early change of carcinogenesis in gallbladder and that LOH on 3p and 9p is related to the progression of gallbladder carcinoma LOH on 13q and 18q is likely to be a late event. LOH on 17p occurs not only in dysplasia but also increases during the subsequent stages. Accumulation of LOH may be associated with carcinogenesis of the gallbladder, but the role of MI may not be significant.

Adult↗
PubMed1999

Time trend of substance use among adolescent students in Taiwan, 1991-1996.

The purpose of this study was to determine the prevalence and time trend of cigarette, alcohol, and illicit substance use among adolescent students in Taiwan, from 1991 through 1996. Subjects were selected through a two-stage random-sampling procedure. In the first stage, the strata were based on the type of school: middle school (13-15 years), high school (16-18), vocational school (16-18), and junior college (first 3 years only, 16-18). In the second stage, the strata were based on grade: one class each for 1st, 2nd, and 3rd grades were randomly selected from each type of school. Students were guaranteed anonymity before the questionnaire was administered. About 12,000 students from 100 schools participated each year in 1991 and 1994-1996. In 1993, 8,320 students from 65 schools participated. The prevalence of smoking and drinking decreased between 1991 and 1994, and then increased between 1994 and 1996. In 1996, the prevalence of illicit substance use was 15.4% for smoking, 16.7% for drinking, and 1.5% for illicit substance use. The rate of illicit substance use was lowest among high school students, followed by middle school students, and higher among students in vocational schools and junior colleges. The percentage of smokers and drinkers who had started early (at age 12 or earlier) rose every year. The prevalence of smoking and drinking habits among girls increased consistently during the study period. The most commonly abused substance was amphetamine. However, in 1996, sniffing glue became more prominent among middle school students, and flunitrazepam became the second most commonly abused substance among high school students.

Adolescent↗
PubMed1998

Molecular epidemiology and trends of HIV-1 subtypes in Taiwan.

To understand the trends of distribution and risk factors associated with different HIV-1 subtypes in different populations in Taiwan, blood samples and questionnaires were collected from 267 male and 21 female HIV-1-infected people in a multicenter survey from 1993 to 1996. This group represented about one quarter of the total registered HIV-1 cases in Taiwan. The HIV-1 subtypes were determined using V3-based peptide-enzyme immunoassays complemented by heteroduplex mobility assay and phylogenetic tree analysis. The results showed that in Taiwan, men were primarily infected with HIV-1B (68.2%) and HIV-1E (27.3%), whereas women were mainly infected with non-B subtypes (4.8% A, 4.8% C, 71.4% E, and 9.5% G). In addition, 71.4% of men with HIV-1B were homosexual or bisexual, whereas 56.2% of men with HIV-1E were heterosexual (p < .001). Although HIV-1E subtype came to Taiwan later than HIV-1B, it has become a major subtype in the heterosexual population.

Acquired Immunodeficiency Syndrome↗
PubMed1998

An epidemic of Malassezia pachydermatis in an intensive care nursery associated with colonization of health care workers' pet dogs.

BACKGROUND: Malassezia species are lipophilic yeasts that are emerging as nosocomial pathogens, particularly in low-birth-weight neonates who receive lipid emulsions. When a cluster of patients with Malassezia pachydermatis infection was identified in an intensive care nursery, we initiated an investigation. METHODS: A case patient was defined as any infant in the intensive care nursery who had a positive culture for M. pachydermatis between October 17, 1993, and January 18, 1995. We conducted a cohort study to identify risk factors for colonization and infection with M. pachydermatis. We collected cultures from the infants and the health care workers and from the health care workers' pets, since this organism has been associated with otitis externa in dogs. RESULTS: Fifteen infants met the case definition: eight with bloodstream infections, two with urinary tract infections, one with meningitis, and four with asymptomatic colonization. The case patients were significantly more likely than the other infants to weigh 1300 g or less (15 of 65 vs. 0 of 419, P<0.001). In a multivariate analysis of infants weighing 1300 g or less, the independent risk factors for colonization or infection with M. pachydermatis were a greater severity of concomitant illness (odds ratio, 19.7; P=0.001), arterial catheterization for nine or more days (odds ratio, 29.5; P=0.027), and exposure to Nurse A (odds ratio, 74.7; P=0.004). In a point-prevalence survey, 9 additional infants, 1 health care worker, and 12 of the health care workers' pet dogs had positive cultures for M. pachydermatis. The isolates from all 15 case patients, the 9 additional colonized infants, 1 health care worker, and 3 of the 12 dogs had identical patterns of restriction-fragment-length polymorphisms. CONCLUSIONS: In this outbreak, it is likely that M. pachydermatis was introduced into the intensive care nursery on health care workers' hands after being colonized from pet dogs at home. The organism persisted in the nursery through patient-to-patient transmission.

Animals↗
PubMed1998

Phenoloxidase activity of hemocytes derived from Penaeus monodon and Macrobrachium rosenbergii.

The phenoloxidase (PO) activity of hemocyte lysate supernatant (HLS) from both tiger shrimp (Penaeus monodon) and giant freshwater prawn (Macro-branchium rosenbergii) was examined by treating HLS with various factors, such as an increase in temperatures from 25 to 70 degrees C, one of four elicitors (beta-1,3-1,6-glucan, zymosan, heat-killed Vibrio cells, and lipopolysaccharide), trypsin, one of three protease inhibitors (soybean trypsin inhibitor, p-nitrophenyl-p'-guanidinobenzoate, and benzamidine), and one of two divalent cations (Mg2+ and Ca2+). The strongest PO activity in both animals was induced at 37 degrees C, while enzyme activity varied according to the concentration of the elicitors or cations added to the HLS samples. The following optimum concentrations were recorded: lipopolysaccharides at 0.5 mg/ml, both beta-glucan and zymosan at 1 mg/ml, and Vibrio cells at 10(6) cells/ml. In addition, for giant freshwater prawn, PO activity increased when HLS was treated with trypsin and decreased when it was separately treated with three protease inhibitors. However, effects of either trypsin or protease inhibitors did not occur in tiger shrimp. Strongest PO activity occurred in HLS treated with 20 mM of either calcium ion or magnesium ion, and the addition of the two cations led to an increase in enzyme activity; a decrease was noted following the treatment with EDTA. Cytochemical analysis revealed that prophenoloxidase system exists in the granulocytes of both tiger shrimp and giant freshwater prawn.

Animals↗
PubMed1998

Late coronary artery stenting in patients with acute myocardial infarction.

BACKGROUND: The safety and efficacy of late coronary artery stenting of the infarct-related artery after acute infarction has not been evaluated previously. METHODS AND RESULTS: Coronary artery stenting was performed in 117 consecutive patients with acute infarction who were receiving ticlopidine/aspirin regimen without coumarin. There were 97 men and 18 women, aged 58+/-11 (mean +/- SD) years. A total of 136 Palmaz-Schatz stents were successfully implanted in 130 lesions 15+/-8 days after acute myocardial infarction (median 9 days) in 115 of 117 (98%) patients. The minimal luminal diameter (MLD) increased from 0.66+/-0.46 to 3.14+/-0.53 mm (P< .001), with an acute gain of 2.49+/-0.61 mm. One patient had acute thrombosis requiring further stenting and another patient received emergency bypass surgery. There was no subacute thrombosis or other complications. During a follow-up duration of 14+/-3 months, 2 patients had angina pectoris develop and 1 died suddenly. Sixty-two patients underwent a follow-up coronary angiography 195+/-36 days after stenting. Restenosis was noted in 8 patients (13%); the MLD was 2.19+/-0.73 mm, the late loss was 0.96+/-0.65 mm (P< .001), the loss index was 0.39+/-0.28, and the net gain was 1.56+/-0.79 mm (P< .001). The angiographic left ventricular ejection fraction increased from 47%+/-12% to 55%+/-12% (P< .001). CONCLUSIONS: Late coronary stenting of the infarct-related artery in patients with acute myocardial infarction is a safe and effective late reperfusion therapy and may be beneficial to the patients.

Adult↗
PubMed1998

Multiplane transesophageal echocardiography in diagnosis of anomalous origin of the left coronary artery from the pulmonary artery: a case report.

Anomalous origin of the left coronary artery from the pulmonary artery in adults is difficult to identify reliably by transthoracic echocardiography (TTE). We describe a 32-year-old woman with this coronary anomaly mimicking a coronary artery fistula on conventional TTE study. This anomaly was suggested by multiplane transesophageal echocardiography (TEE) and subsequently confirmed by coronary angiography. Multiplane TEE thus may serve as a first-line diagnostic tool for detecting anomalous origin of coronary arteries.

Adult↗
PubMed1997

A clinicopathological study of unsuspected carcinoma of the gallbladder.

We investigated the incidence of unsuspected gallbladder (GB) carcinomas in a total of 527 consecutive GB specimens resected for benign biliary disease and their clinicopathological features. The GBs were examined microscopically using stepwise tissue sections at 5 mm interval. Clinical and pathological findings were analysed in the cases of unsuspected carcinoma. The 527 patients included 314 women and 213 men (mean age 56.1 years). The incidence of unsuspected GB carcinomas detected during or after cholecystectomy was 1.89%. In ten patients with unsuspected carcinomas, symptoms and signs were nonspecific. Abdominal US showed GB stones (8), thickening of GB wall (1), empyema (2) and a polyp (1). Macroscopically, infiltrative type was the most common. Microscopic examination showed tubular adenocarcinoma. Carcinoma was confined to the mucosa or muscularis (early carcinoma) in 5 cases (50%). The prognosis was good in the patients with early carcinoma, but very bad in advanced cases. In conclusion, unsuspected GB carcinoma was incidentally found in 1.89% of GBs removed for benign biliary disease and a considerable number of these unsuspected cases have an early carcinoma.

Abdominal Pain↗