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Biomedical subjects

M L Yu

Publications and source records attributed to M L Yu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Virologic factors related to interferon-alpha-induced thyroid dysfunction in patients with chronic hepatitis C.

OBJECTIVE: Hepatitis C virus (HCV), being reported to be associated with a high prevalence of serological markers of autoimmunity in HCV-infected patients, and possibly sharing partial sequences in amino acid segments with thyroid tissue antigens, may be associated with interferon-alpha (IFN-alpha)-induced thyroid dysfunction in chronic hepatitis C patients. We conducted this study to clarify the issue. DESIGN AND METHODS: One hundred and fifty chronic hepatitis C patients with normal baseline thyroid function were treated with IFN-alpha 2a, 2b and n1 (3-6 million Units three times weekly for 24 weeks). Pretreatment sera were tested for HCV genotype and HCV RNA levels. Serum thyrotropin, total thyroxine and free thyroxine index were performed every 4 weeks for 24 weeks followed by every 8 weeks for another 24 weeks. RESULTS: Twenty-one (14.0%) patients developed early thyroid dysfunction (abnormal thyroid function during the first 3 months of therapy). Female gender, lower HCV RNA levels, IFN-alpha n1 and a lower IFN-alpha dose were significantly associated with early thyroid dysfunction. On multivariate analysis, gender, IFN-alpha preparation and HCV RNA levels were the significant factors associated with early thyroid dysfunction. Seven (4.7%) patients developed thyroid dysfunction during the second 3 months of IFN-alpha therapy. Taken together, 18.7% patients developed thyroid dysfunction. Female, mixed HCV genotype infection and lower HCV RNA levels were significantly associated with thyroid dysfunction. However, only gender remained significantly associated with IFN-alpha-induced thyroid dysfunction in multivariate analysis. CONCLUSIONS: The virologic features of HCV may be associated with thyroid dysfunction in chronic hepatitis C patients treated with IFN-alpha. Nevertheless, gender still plays the most important role in IFN-alpha-induced thyroid dysfunction.

Adolescent↗
PubMed2000

The epidemiology of TT virus (TTV) infection in a hepatitis C and B virus hyperendemic area of southern Taiwan.

TT virus (TTV) is a newly isolated DNA virus from the serum of a patient with posttransfusion hepatitis of unknown etiology in 1997. To evaluate the clinical and molecular characteristics of TT virus (TTV) in a hepatitis C virus (HCV) and B (HBV) hyperendemic area (Masago), 200 residents were enrolled in the study. The sera were tested for alanine aminotransferase (ALT), HCV RNA and GB virus C/Hepatitis G virus (HGV) RNA, TTV DNA, HBsAg, anti-HCV and antibodies to HGV E2-protein (anti-E2). TTV DNA was positive in 99 of the 200 sera with a prevalence rate of 49.5%. The prevalence of HBsAg, anti-HCV, HCV RNA, HGV RNA, anti-E2 and HGV exposure (defined as positive for serum HGV RNA and/or anti-E2) was 38.9%, 69.5%, 64.5%, 17.0%, 25.5% and 39.5%, respectively. Neither clinical nor virological factors were associated with TTV viremia. The rate of ALT abnormality was significantly elevated in HCV RNA-positive (34.9%) than -negative (7.0%) residents (p < 0.001). HCV viremia was the only factor significantly associated with ALT elevation by multiple logistic regression (odds ratio: 6.96; 95% C.I.: 2.60-18.7). We concluded that in this HCV/HBV hyperendemic area, the prevalence of TTV DNA was high. No significant clinical factor was observed to be associated with TTV infection. TTV infection is not related to abnormal ALT levels and ALT abnormality was mainly attributable to HCV but not TTV, HBV or HGV infection.

Adult↗
PubMed1999

Recent trend of polychlorinated dibenzo-p-dioxins and their related compounds in the blood and sebum of Yusho and Yu Cheng patients.

We investigated the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and their related compounds in blood and sebum from Yusho and Yu-Cheng patients and findings compared with those of normal subjects. Concentrations of these compounds in blood and sebum still were obviously reflected the chemical concentration in the causal rice oil ingested 17 or 26 years since the outbreak. In addition, sebum form the body surface was the most useful sample for monitoring the amount of chemicals contaminating the human body.

Adult↗
PubMed1999

Clinical application of the Quantiplex HCV RNA 2.0 and Amplicor HCV Monitor assays for quantifying serum hepatitis C virus RNA.

AIM: To compare the performance characteristics and clinical application of two different technologies for quantifying serum hepatitis C virus (HCV) RNA levels. METHODS: HCV RNA was quantified by Amplicor HCV Monitor assay (Amplicor) and Quantiplex HCV RNA 2.0 assay (bDNA-2) in 119 sera from 107 HCV infected patients. RESULTS: Both assays had similar sensitivity (79.4% for Amplicor; 86.0% for bDNA-2), acceptable coefficients of variation (5.3% in Amplicor; 2.6% in bDNA-2), and good linearity (r2 > or = 0.98). There was a positive correlation between quantification values of both methods (r = 0.683, p < 0.001). The Amplicor values were on an average 1.76 log lower than bDNA-2 results. Male subjects and HCV genotype 1b were significantly associated with higher viral load determined by Amplicor, but not with viral load measured by bDNA-2. In 70 chronic HCV infected patients treated with interferon alfa, mean (SD) pretreatment viral load in 27 complete responders (3.47 (0.84) logs for Amplicor, 5.63 (0.58) for bDNA-2) was significantly lower than in non-responders (4.43 (1.01) logs for Amplicor, 6.10 (0.67) logs for bDNA-2; p < 0.001). Cut off points of 3.9 logs for Amplicor and 5.8 logs for bDNA-2 were determined to be the best for predicting response to interferon alfa, giving acceptable sensitivity (70.4%, 74.1%), specificity (72.1%, 65.1%), and accuracy (71.4%, 68.6%), respectively. CONCLUSIONS: Both the Amplicor and bDNA-2 assays are clinically useful methods for HCV RNA quantification and are reliable for predicting the outcome of treatment, despite differences in absolute quantification values and in the correlation between HCV genotypes and viral load.

Adult↗
PubMed1999

Chloracne, goiter, arthritis, and anemia after polychlorinated biphenyl poisoning: 14-year follow-Up of the Taiwan Yucheng cohort.

In 1979, a mass poisoning involving 2,000 people occurred in central Taiwan from ingestion of cooking oil contaminated by polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs). We studied the prevalence of medical conditions in the exposed individuals and in a neighborhood control group. Starting with a registry of the exposed individuals from 1983, we updated the addresses of exposed individuals and identified a control group matched for age, sex, and neighborhood in 1979. In 1993, individuals 30 years of age or older were interviewed by telephone. We obtained usable information from 795 exposed subjects and 693 control subjects. Lifetime prevalence of chloracne, abnormal nails, hyperkeratosis, skin allergy, goiter, headache, gum pigmentation, and broken teeth were observed more frequently in the PCB/PCDF-exposed men and women. The exposed women reported anemia 2. 3 times more frequently than controls. The exposed men reported arthritis and herniated intervertebral disks 4.1 and 2.9 times, respectively, more frequently than controls. There was no difference in reported prevalences of other medical conditions. We conclude that Taiwanese people exposed to high levels of PCBs and PCDFs reported more frequent medical problems, including skin diseases, goiter, anemia, and joint and spine diseases.

Acne Vulgaris↗
PubMed1998

A SAS macro for a simulation study of imputation methods for missing values--an application of Bebbington's algorithm.

This paper presents a SAS macro for a simulation study of comparing a new variant of hot-deck imputation with mean imputation for missing values, in which a simple algorithm proposed by Bebbington (Applied Statistics, 1975) for carrying out simple random sampling without replacement was employed to draw repeated random samples efficiently. A simulated example of drawing repeated random samples from a regional survey of obesity in school children was used to demonstrate the SAS macro.

Algorithms↗
PubMed1998

Prevalence and manifestations of hepatitis C seropositivity in children in an endemic area.

BACKGROUND: According to our previous studies, Paisha Township in Penghu Islets is an endemic area for hepatitis B virus and hepatitis C virus (HCV) infection and for hepatocellular carcinoma. We conducted this study to understand the prevalence of anti-HCV seropositivity among children in this area and to observe clinical manifestations of anti-HCV-positive children. METHODS: In March, 1994, 1164 (93.6%) of 1243 students from all 6 kindergartens, 9 primary schools and 3 middle schools in Paisha Township participated in the screening for anti-HCV by enzyme immunoassay with second generation commercial kits (Abbott EIA 2.0). Anti-HCV tests were duplicated for the positive sera in 2 laboratories. All anti-HCV-positive children were followed annually for 2 years. RESULTS: The prevalences of children from kindergartens (ages 3 to 6 years), primary schools (ages 7 to 12 years) and middle schools (ages 13 to 15 years) were 0% (0 of 229), 0.8% (5 of 617) and 1.9% (6 of 318), respectively. Initially the optic density (OD) values of anti-HCV were > 2.0 in 4 cases (36%), between 1.0 and 2.0 in 2 cases, and < 1.0 in the other 5 cases. None had sonographic parenchymal changes in the liver. In the 2-year follow-up of the anti-HCV-positive subjects, type 2a HCV-RNA persisted in 3 of 4 children with an OD of anti-HCV more than 2.0; 2 of them had 2 elevations of alanine transaminase values. Four of 7 children with an OD of 2.0 or less had a decrease in OD values in the follow-up examinations, and 2 of them became anti-HCV-negative. CONCLUSION: Only 36% (4 of 11) of anti-HCV-positive children had an OD of > 2.0. Subjects with sequentially low OD might recover from chronic HCV infection without detectable HCV RNA and with normal alanine aminotransferase values.

Adolescent↗
PubMed1998

Prevalence study of thyroid dysfunction in the elderly of Taiwan.

The present study was aimed at investigating the prevalence of thyroid dysfunction in the elderly, aged 65 years or older, in a community of southern Taiwan. By using the records of the local household registry, a sampling frame for the elderly population was constructed, and a sample of 1,400 subjects was drawn by simple random sampling. After the exclusion of nonresponse subjects, 917 subjects aged between 65 and 88 years (mean 71.9) were included in our survey. The serum thyrotropin levels of these participants were measured by monoclonal antibodies TSH immunoradiometric assays. A normal range, 0.45-4.65 microU/ml, was determined from the middle 95% of the TSH distribution of 140 'disease-free' subjects. By reference to the normal range, 23 (2.51%) participants had high (> 4.65 microU/ml), and 41 (4.47%) had low (< 0.46 microU/ml) TSH levels. The overall prevalence of thyroid dysfunction in the sample was 6.98%. Of the 23 participants with high TSH levels, 8 (34.8%) had low free T4 values (< 1.21 ng/dl), so-called overt hypothyroidism, and of the 41 participants with low TSH levels, only 1 (2.4%) had high T3 values, so-called T3 thyrotoxicosis. Antithyroid antibodies were found in 56.5% of those with high TSH levels but only 12.2% of those with low TSH levels (odds ratio = 8.53, 95% confidence limits = 2.55-28.50, p < 0.001). This result indicates that autoimmune disease is still the major cause of hypothyroidism in aged people. However, the prevalence of subclinical hyperthyroidism is higher than that of subclinical hypothyroidism and it might relate to nonautoimmune factors.

Aged↗
PubMed1997

Increased mortality from chronic liver disease and cirrhosis 13 years after the Taiwan "yucheng" ("oil disease") incident.

In 1979, a mass poisoning involving some 2,000 persons occurred in central Taiwan from cooking oil contaminated by polychlorinated biphenyls (PCBs) and their heat-degraded byproducts, including polychlorinated dibenzofurans (PCDFs). The responsible health department registered cases for clinical purposes between 1979 and 1983. The exposed persons are referred to as the "yucheng" (oil disease) cohort. PCBs and PCDFs are toxic chemicals widely dispersed in the environment and in human tissue, which persist long after exposure. The consequences of exposure to these agents are not well understood. We traced the cohort through December 31, 1991, and compared overall and cause-specific mortality of 1,837 "yucheng" subjects with age, gender, and calendar time-specific mortality rates for the Taiwan general population. Eighty-three deaths were identified from 23,404 observed person-years. Even though the overall standardized mortality ratio (SMR) was 0.8 (95% confidence interval (CI) 0.7-1.0), there was a substantial elevation in the mortality rate for chronic liver disease and cirrhosis (10 deaths, SMR = 2.7, 95% CI = 1.3-4.9). Mortality from malignant neoplasms and other causes was not significantly different from that of the Taiwan population. PCB/PCDF exposure appears to promote the development of severe liver disease, perhaps in combination with known risk factors such as infection with hepatitis B virus. Further follow-up of this young cohort is necessary to see if the consequences include hepatic cancer.

Adolescent↗
PubMed1997

Blood serum levels of PCBs and PCDFs in Yucheng women 14 years after exposure to a toxic rice oil.

In 1979, a mass poisoning of more than 2000 people occurred in central Taiwan due to consumption of rice-bran oil contaminated with PCBs and their heat-degraded byproducts. The incident was later referred to as Yucheng (oil disease). Serum samples from 56 women with the 1979 exposure were collected in February 1992 and analyzed for their contaminant content using sample enrichment and isotope dilution mass spectrometry. In most of the samples, levels of PCDFs and PCBs were detectable, and the median values of 2,3,4,7,8-PCDFs and 1,2,3,4,7,8-PCDFs were 1,030 and 2,220 ng/kg serum lipid, respectively. The median level of the total PCBs on a whole weight basis was 8,730 ng/kg. The PCB/PCDF concentrations in Yucheng women 14 years after the toxic exposure were still one to two orders of magnitude higher than controls. Concentrations of PCB levels in 1992 were positively correlated with the 1980-1981 measured PCB levels in these women and both PCBs and PCDFs were negatively correlated with the total duration when these women breast fed their children between 1979 and 1992. It is concluded that serum levels of congener-specific PCBs/PCDFs in exposed women are good indicators of previous exposure and may provide important information for more reliable estimation of dose-response relationship.

Benzofurans↗
PubMed1997

Assessment of the patient with chronic cough.

Chronic cough, defined as cough that persists for 3 weeks or longer, is one of the most common symptoms evaluated by a primary-care physician. With the exclusion of cigarette smoking, postnasal drip, asthma, and gastroesophageal reflux are responsible for more than 80% of the causes of chronic cough. Elicitation of a thorough history and performance of a physical examination will usually provide clues about the cause of chronic cough. The use of diagnostic tests including methacholine challenge, gastroesophageal reflux studies, and sinus imaging is based on clinical suspicion. Treatment of chronic cough is aimed at the underlying cause.

Asthma↗
PubMed1997

Consequences of analysing complex survey data using inappropriate analysis and software computing packages.

In the analysis of complex survey data such as stratified multi-stage cluster samples, ignoring the design effects such as clustering and stratification usually will lead to erroneous conclusions. In this paper, we will demonstrate the consequences in the estimation of means and proportions by two examples from a stratified two-stage cluster sample. A brief review of methodology will be presented, and some suggestions on computational issues will be provided.

Adult↗
PubMed1997

Pneumocystis carinii induces ICAM-1 expression in lung epithelial cells through a TNF-alpha-mediated mechanism.

Inflammatory cell recruitment contributes to respiratory impairment during Pneumocystis carinii pneumonia. We evaluated expression of intercellular adhesion molecule-1 (ICAM-1), a key participant in leukocyte accumulation, in rats with P. carinii pneumonia. Immunostaining for ICAM-1 was most marked on bronchiolar epithelium but was also evident on type II pneumocytes, endothelium, and macrophages. Lung from normal and dexamethasone-treated uninfected animals exhibited markedly less ICAM-1. We hypothesized that P. carinii promoted ICAM-1 expression in epithelium through tumor necrosis factor-alpha (TNF-alpha) release from macrophages or that P. carinii directly stimulated ICAM-1 expression. Alveolar macrophages were incubated with P. carinii, and the medium was added to A549 epithelial cells. Treatment of macrophages with P. carinii enhanced A549 ICAM-1, which was inhibited with antibody to TNF-alpha. To determine whether P. carinii alone also stimulated ICAM-1, A549 cells were cultured with P. carinii, also augmenting ICAM-1. Of note, A549 ICAM-1 expression from P. carinii alone was less than with P. carinii-exposed macrophages. Thus ICAM-1 is enhanced in lung epithelium during P. carinii infection, in part, through TNF-alpha-mediated mechanisms.

Animals↗
PubMed1996

Cardiorespiratory function, flexibility, and body composition among geriatric Tai Chi Chuan practitioners.

OBJECTIVE: To evaluate the health-related fitness of geriatric Tai Chi Chuan (TCC) practitioners. DESIGN: Case-control study of a TCC group and a group of sedentary controls. SETTING: Research project at a hospital-based exercise physiology laboratory. PARTICIPANTS: Seventy-six community-dwelling senior persons (mean age 69.3 +/- 3.9 yr), a TCC group that included 22 men and 19 women and a control group of sedentary subjects that included 18 men and 17 women with matched age and body size. INTERVENTION: The TCC group had practiced TCC regularly for 11.8 +/- 5.6 years, with an exercise frequency of 4.3 +/- 1.3 times per week. Each session included 20 minutes of warm-up, 24 minutes of TCC training, and 10 minutes of cool-down. Exercise intensity was estimated to exceed 70% of maximal heart rate (HRmax). MAIN OUTCOME MEASURE: Breath-by-breath measurement of cardiorespiratory function was obtained during the incremental exercise of leg cycling. Flexibility of thoracic/lumbar spine was measured by an electronic inclinometer. Percentages of body fat was calculated from biceps and subcapsular skinfolds. RESULTS: In the peak exercise, men in the TCC group showed 19% higher peak oxygen uptake (VO2peak) in comparison with their sedentary counterparts (26.9 +/- 4.7 mL/kg/min vs 21.8 +/- 3.1 mL/kg/min). Women in the TCC group also showed 18% higher VO2peak than in the sedentary group (20.1 +/- 2.9 mL/kg/ min vs 16.5 +/- 2.0 mL/kg/min). The TCC group also showed higher oxygen uptake at the ventilatory threshold. In addition, the TCC practitioners were characterized by greater flexibility and lower percentage of body fat in comparison with their sedentary counterparts. CONCLUSION: It is concluded that TCC training has benefits for health-related fitness, and it may be prescribed as a suitable conditioning exercise for the elderly.

Aged↗
PubMed1996

Early diagnosis of necrotizing fasciitis by utilization of ultrasonography.

Necrotizing fasciitis is a rare and rapid progression soft tissue infection. The only identifiable feature is tissue necrosis along a single fascia plane. Because the skin is initially spared, it is difficult for early recognition prior to extensive tissue destruction. Ultrasonography was used for early diagnosis of this infection in five cases. All 5 patients presented with severe cellulitis. Under the suspicion of necrotizing fasciitis, ultrasonography was performed before surgical debridement. Tissue biopsy was done for histological confirmation of the diagnosis. Three patients were proven to have necrotizing fasciitis and two cellulitis only. The ultrasonographic findings of necrotizing fasciitis included: 1) irregularity of the fascia; 2) abnormal fluid collections along the fascia plane; and 3) diffuse thickening of the fascia when compared with the control site in the normal limb. However, in severe infectious cellulitis, the above mentioned findings were not observed. Our results indicate the usefulness of the ultrasonography for early diagnosis of necrotizing fasciitis.

Adult↗
PubMed1996

The status of serum hepatitis B virus DNA in HBSAG-positive hepatocellular carcinoma.

To elucidate the status of serum hepatitis B virus (HBV) DNA in HBsAg-positive hepatocellular carcinoma (HCC), 100 type B chronic liver disease (CLD) patients and 19 HCC patients were studied. The positive rate of serum HBV DNA in HBeAg-positive CLD patients was significantly higher than that in HBeAg-negative CLD patients, and the correlation between the presence of serum HBV DNA and patients' age showed a negative trend. In contrast, the positive rates of serum HBV DNA in HCC patients were not related to the status of HBeAg and age, and the positive rate of serum HBV DNA in HBeAg-negative HCC patients was significantly higher than that in HBeAg-negative CLD patients. Nevertheless, the serum concentrations of HBV DNA in HCC patients were significantly lower than those in CLD patients. These results suggest that replication of HBV in HCC patients might differ from that in CLD patients, and that persistent low-level HBV replication might be related to the presence of HCC.

Adult↗