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Biomedical subjects

Y C Ko

Publications and source records attributed to Y C Ko.

At least 19 recordsLinked to original sources
PubMed2003

Cockroaches (Periplaneta americana and Blattella germanica) as potential mechanical disseminators of Entamoeba histolytica.

Since cockroaches feed on feces, they may disseminate infective agents with the fecal-oral route. A field survey and experiments were conducted to determine the role of cockroaches in the dissemination of Entamoeba histolytica. Periplaneta americana (n=299) and Blattella germanica (n=29) were collected from 11 primary schools in an urban area of South Taiwan. E. histolytica/E. dispar cysts were found on the cuticle and/or in the digestive tract of P. americana (25.4%) whereas cysts were only isolated from the digestive tract of B. germanica (10.3%). E. histolytica cysts were found on the cuticle and/or in the digestive tract of both species after exposure to 1000 or 100 cysts/g feces for 24 h. These findings indicate that cockroaches may harbor the E. histolytica cysts and play a role as potential mechanical disseminators.

Animals↗
PubMed2003

Climate, traffic-related air pollutants and allergic rhinitis prevalence in middle-school children in Taiwan.

The prevalence of allergic rhinitis, a common respiratory disorder, may be rapidly increasing. Epidemiological studies, however, indicate little about its association with climatic factors and air pollution. The relationship between traffic-related air pollutants and allergic rhinitis in middle-school students was therefore investigated. In a nationwide survey of middle-school students in Taiwan conducted in 1995/1996, the lifetime prevalence of physician-diagnosed allergic rhinitis and typical symptoms of allergic rhinitis were compared with air-monitoring station data on temperature, relative humidity, sulphur dioxide (SO2), nitrogen oxides (NOx), ozone (O3), carbon monoxide (CO) and particulate matter with a 50% cut-off aerodynamic diameter of 10 microm (PM10). A total of 331,686 nonsmoking children attended schools located within 2 km of 55 stations. Mean (range) annual exposures were: CO 853 (381-1,610) parts per billion (ppb), NOx 35.1 (10.2-72.4) ppb, SO2 7.57 (0.88-21.2) ppb, PM10 69.2 (40.1-116.2) microg x m(-3), O3 21.3 (12.4-34.1) ppb, temperature 22.9 (19.6-25.1) degrees C, and relative humidity 76.2 (64.8-86.2)%. The prevalence of physician-diagnosed allergic rhinitis was 28.6 and 19.5% in males and females, respectively, with prevalence of questionnaire-determined allergic rhinitis 42.4 and 34.0%. After adjustment for age, parental education and history of atopic eczema, physician-diagnosed allergic rhinitis was found to be associated with higher nonsummer (September-May) warmth and traffic-related air pollutants, including CO, NOx and O3. Questionnaire-determined allergic rhinitis correlated only with traffic-related air pollutants. Nonsummer warmth and traffic-related air pollution, probably mediated through exposure to common allergens such as dust mites, are possible risk factors for allergic rhinitis in middle-school-aged children.

Adolescent↗
PubMed2001

Betel quid chewing and risk of adverse birth outcomes among aborigines in eastern Taiwan.

It is known that substance abuse during pregnancy is associated with increased risk of adverse birth outcomes. The aim of this study was to determine the use of alcohol, cigarettes, betel quid, and drugs among pregnant aboriginal women and to assess the risk of adverse effects of betel quid use on birth outcomes in eastern Taiwan. Of a total of 229 women recruited into this study, 32 women with adverse birth outcomes constituted the case group. Analyses revealed that adverse birth outcomes were associated with maternal betel quid chewing and maternal age. After adjusting for maternal age, the risk of adverse birth outcome was five times higher among betel quid chewing women as compared to substance nonusers. Based on this finding, it is suggested health education, especially when concerned with the harmful effects of substance abuse, which includes betel quid use during pregnancy, should be stressed in concert with routine prenatal care.

Alcohol Drinking↗
PubMed2001

Adaptations of linkage and association methods for the study of asthma, a complex trait.

Early studies that found significant linkage between markers on 5q and asthma and IgE have not been reproduced. In an attempt to improve the power of these studies we performed a variance components linkage analysis and transmission-disequilibrium tests (TDT) with haplotypes using markers on 5q, using the Southampton and Perth data sets supplied by GAW. The linkage analysis with covariates revealed a maximum lod of 1.57 in the Perth families. The addition of age and RAST significantly improved the fit of the null models but did not improve the lod scores. The TDT tests showed a marginally significant association with D5S393 and D5S399 and with three markers together (IL9, IL4, D5S393). We conclude that further studies are needed to delineate the environmental contribution to this disease so that the genetic factors can be more easily identified. In addition, haplotype analysis may help to identify specific genetic effects.

Adolescent↗
PubMed2001

The heterogeneity in risk factors of lung cancer and the difference of histologic distribution between genders in Taiwan.

OBJECTIVE: The difference in histologic patterns of lung cancer between men and women in Taiwan may be associated with the heterogeneity in causal factors of lung cancer between the sexes. A sex- and age-matched case-control study was designed to investigate such a relationship. METHODS: Cases consisted of 236 male and 291 female incident cases with newly diagnosed and histologically confirmed primary carcinoma of the lung, and were compared to one or two individually matched controls. RESULTS: Cigarette smoking, occupations, and previous tuberculosis history were found to independently correlate with an elevated risk of squamous/small cell carcinoma and adenocarcinoma for male patients. However, there was little difference in the effect of these risk factors except smoking. The use of fume extractors in the kitchen, and the habit of waiting to fry after the fumes were emitted, separately explained the majority of the attributable fraction of female squamous/small cell carcinoma (28.2%) and adenocarcinoma (47.7%). With the exception of a kitchen with fume extractors and a clinical history of tuberculosis, the environmental causal factors of lung cancer were heterogeneous between these two histologic cell groups. CONCLUSIONS: Our results suggested that the causal factors of lung cancer might be specific for the type of tumor concerned. The gender-specific risk factors of lung cancer could partly explain the difference in cell-type distribution between men and women.

Adenocarcinoma↗
PubMed2001

Formation of protoberberine-type alkaloids by the tubers of somatic embryo-derived plants of Corydalis yanhusuo.

The effects of 0.5 - 5 mg/l abscisic acid [ABA], 0.5 - 10 mg/l (2RS,3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)pentan-3-ol [paclobutrazol] and 0.5 - 2 mg/l alpha-cyclopropyl-alpha-(4-methoxyphenyl)-5-pyrimidinemethanol [ancymidol], 0.5 - 5 mg/l gibberellic acid [GA(3)] and 15 - 100 mg/l polyethylene glycol [PEG] 4000 supplemented in half-strength Murashige and Skoog's (MS) medium on the production of the two major protoberberine-type alkaloids (D,L-tetrahydropalmatine and D-corydaline) by the tubers of somatic embryo-derived plants of Corydalis yanhusuo were examined. Somatic embryo derived plants were also maintained for 6 months on half-strength MS medium containing 0.1 mg/l GA(3) or 0.5 mg/l paclobutrazol. The alkaloid contents were determined by high performance liquid chromatography (HPLC). The analysis revealed that the contents of D,L-tetrahydropalmatine and D-corydaline in the tubers of somatic embryo-derived plants were higher than the marketed crude drug and varied with growth regulator/PEG-4000 treatment and the age of the plant.

Abscisic Acid↗
PubMed2001

Mycophenolate mofetil reduces renal cortical inducible nitric oxide synthase mRNA expression and diminishes glomerulosclerosis in MRL/lpr mice.

Overexpression of inducible nitric oxide synthase (iNOS) has been implicated in the pathogenesis of lupus glomerulonephritis. Mycophenolate mofetil (MMF), a novel immunosuppressive agent, is currently used in organ transplantation and under evaluation for treatment of autoimmune disorders. Mycophenolic acid, the active metabolite of MMF, has been shown to suppress cytokine-induced nitric oxide production in vitro. The aim of this study was to evaluate the effect of MMF on the expression of renal cortical iNOS mRNA and protection against glomerulonephritis in MRL/lpr mice. Three-month-old MRL/lpr mice (n = 6) displaying clinical symptoms of glomerulonephritis were treated for 3 months with MMF (90 mg/kg/day) dissolved in a vehicle. Controls were age- and sex-matched mice (n = 6) that received the vehicle alone. By reverse-transcription competitive polymerase chain reaction, we found that the renal cortical iNOS/beta-actin mRNA ratio was reduced by 30.8% (P <.05) in MMF-treated mice. Furthermore, MMF significantly reduced urinary nitrite production and degree of glomerulosclerosis. The glomerular volume was reduced by 17.5% (P <.001). Proteinuria was also significantly reduced in the MMF-treated group. However, by electrophoretic mobility shift assay, the nuclear binding of nuclear factor-kappaB (NF-kappaB) was not affected by MMF treatment. We conclude that in addition to its immunosuppressive action, MMF may reduce renal cortical iNOS mRNA expression and diminish glomerulosclerosis in MRL/lpr mice independent of modulation of the NF-kappaB pathway.

Animals↗
PubMed2001

Familial risk of asthma among adolescents and their relatives in Taiwan.

Although family studies have established that asthma has a hereditary basis, little evidence has been presented about the family risk of simple asthma (AS or nonatopic asthma) and asthma with other atopic diseases (AWAD or atopic asthma) after adjusting for potential risk factors. In this study, data were collected on demographic variables and a wide range of known risk factors for asthma. Study participants were asthmatic adolescents and controls, and their relatives. The role of a familial history of asthma and atopic diseases in predicting asthma risk among asthmatic adolescents and their relatives was evaluated in a population-based family study conducted in southern Taiwan. Asthma risk factor data were collected through telephone interviews with students' parents for 207 asthmatic adolescents 11-16 years of age, their 1600 relatives, and 207 nonasthmatic adolescents in the control group and their 1638 relatives. The results show (after adjusting potential confounders) that a family history of asthma is highly associated with asthma in adolescents. Having two or more family members with asthma was associated with a 3.4-fold (95% confidence interval [CI] = 1.0-12.0) increased risk of asthma among adolescents. Logistic regression was used to assess the effects of having an asthmatic relative and the effect of atopic diseases among relatives of cases. Having a family history of asthma and other atopic conditions, such as rhinitis and atopic dermatitis (adjusted odds ratio [AOR] = 3.64, 95% CI = 2.29-5.74 and AOR = 1.94, 95% CI = 1.53-2.46, respectively), was found to be a significant predictor of asthma in children. Along with a history of allergic rhinitis or atopic dermatitis, familial risks of asthma occurring in adolescents with and without other atopic diseases will be analyzed separately. A critical finding was the significant difference in a risk of asthma and atopic diseases among the relatives of asthma cases with atopic diseases and controls. However, for relatives of asthma cases without atopic diseases compared to control probands, AORs were highly significant for family history of asthma, but not for the family history of atopic diseases. These findings suggest that both forms of asthma may be hereditary, but there are differences in their modes of inheritance. Atopic status itself did not predispose a child to AS. A concomitant inheritance of a predisposition to asthma and atopic condition for AWAD cases was suggested.

Adolescent↗
PubMed2001

Role of urbanization and air pollution in adolescent asthma: a mass screening in Taiwan.

BACKGROUND AND PURPOSE: The prevalence of asthma in school children in Taiwan is increasing. This study used mass screening among middle school children in Taiwan to determine the prevalence of asthma and related factors. METHODS: Data were collected from parents using a self-reported questionnaire and from children using the International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire. Six study teams conducted the survey nationwide in 1995-1996, with the assistance of middle school nurses and teachers. RESULTS: Among the 1,018,031 students at 795 middle schools who returned questionnaires, 8.5% had a history of asthma (ranging in prevalence from 4.2% to 13% in 25 areas). The prevalence of asthma was higher in boys than in girls (10.0% vs 7%) and was highest in more urbanized areas (11.2%), followed by moderately urbanized areas (7.4%) and less urbanized and rural areas (6.5%). Controlling for age, family smoking, family incense burning, and parental education level, multivariate logistic regression models indicated that children living in an area with heavy air pollution were more likely to have asthma than those in an area with no or light pollution (odds ratio, OR = 2.01 and 95% confidence interval, CI = 1.94-2.09 based on parental ranking of pollution level, or OR = 1.30 and 95% CI = 1.18-1.42 based on pollution level reported by the Environmental Protection Administration). CONCLUSIONS: Adolescent asthma in Taiwan is most prevalent in the most urbanized areas and decreases in prevalence in less urbanized areas. This study also found that higher parental education level and higher area air pollution were associated with higher adolescent asthma prevalence.

Adolescent↗
PubMed2000

Segregation analysis of asthma: recessive major gene component for asthma in relation to history of atopic diseases.

Although asthma has a significant heritable component, the mode of inheritance remains controversial because of the complexity of the disease and the influence of environmental factors. Segregation analysis for asthma are performed with and without a history of atopic diseases (dermatitis and rhinitis) after adjusting for environmental factors. To investigate whether asthma may be inherited through a major gene with two alleles, the REGD program of the Statistical Analysis for Genetic Epidemiology (SAGE) package was conducted in 1,990 individuals from 227 families with at least one asthmatic child in a cross-sectional study of respiratory diseases in Southern Taiwan. Other covariates adjusted for included age, sex, current smoking, and environmental tobacco smoking. The hypothesis of Mendelian model and no parent-offspring transmission was rejected. However, when the variables of atopic disease and environmental factors were included in the model as covariates, the models for a two-allele gene with a recessive or codominant inheritance could not be rejected, and Akaike's Information Criterion was smaller (1,377. 13) for the recessive model than all of the other models tested, assuming a major gene with a population frequency of 0.56 +/- 0.04. However, Mendelian model without family effect was rejected. In conclusion, a history of asthma in parents is a strong risk factor for asthma in offspring. Under the assumptions of the applied segregation, at least one major gene exists that could be a gene involved also in allergy. However, the data suggest that a single locus gene explains a portion of asthma that is related to the history of atopic diseases. In addition, a polygenic/multifactorial (genetic and environmental factors) influence with a recessive component inheritance may be involved in the pathogenesis of asthma.

Adolescent↗
PubMed2000

Chinese food cooking and lung cancer in women nonsmokers.

Cigarette smoking cannot fully explain the epidemiologic characteristics of lung cancer in Taiwanese women, who smoke rarely but have lung cancer relatively often. In a previous study, the authors suspected that exposure to fumes from cooking oils was an important risk factor for lung cancer in Taiwanese women nonsmokers in the Republic of China. In a new case-control study conducted in 1993-1996, they further explored the association of oil fumes with lung cancer in women. Two sets of controls were used concurrently. The subjects were 131 nonsmoking incident cases with newly diagnosed and histologically confirmed primary carcinoma of the lung, 252 hospital controls hospitalized for causes unrelated to diseases of smoking, and 262 community controls; all controls were women nonsmokers matched by age and date of interview. Details on cooking conditions and habits were collected, in addition to other epidemiologic data. Lung cancer risk increased with the number of meals per day to about threefold for women who cooked these meals each day. The risk was also greater if women usually waited until fumes were emitted from the cooking oil before they began cooking (adjusted odds ratios = 2.0-2.6) and if they did not use a fume extractor (adjusted odds ratios = 3.2-12.2). These results suggest that a proportion of lung cancer may be attributable to the habit of waiting until the cooking oil has been heated to a high temperature before cooking the food.

Adult↗
PubMed2000

Work stress among six professional groups: the Singapore experience.

Recent developments in stress research have called for attention to how social structures influence the stress and coping processes. This paper examines the experience of work stress among professionals in Singapore and argues that workers' experiences in the workplace are influenced not only by individual personality and job nature, but also by structural forces shaping the profession, the social organization of work institutions and the development of the economy. Data were collected from a survey of professionals in Singapore conducted in 1989-1990. The sample consisted of 2570 men and women from six different professions and para-professions, namely general practitioners, lawyers, engineers, teachers, nurses and life insurance personnel. Results showed that performance pressure and work-family conflicts were perceived to be the most stressful aspects of work. These two stressors also significantly contributed to the experience of overall work stress. Further, stress arising from work-family conflicts, performance pressure and poor job prospects was negatively associated with the level of work satisfaction. These findings were discussed in the contexts of increasing professionalization and de-professionalization and the growing emphases on productivity and efficiency in a quickly developing economy.

Adult↗
PubMed2000

Serum alanine aminotransferase levels in relation to hepatitis B and C virus infections among drug abusers in an area hyperendemic for hepatitis B.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are the major agents responsible for hepatitis in Taiwan. The purpose of this study was to assess the serum alanine aminotransferase (ALT) activity in relation to HBV and HCV infection among drug abusers. This survey included 769 male drug abusers aged 14-59 years, from the Kaohsiung Narcotic Abstention Institute and Kaohsiung Prision. The prevalence of HBsAg seropositivity was 21.5%, and anti-HCV seropositivity was 27.2%, respectively. Drug abusers with HBsAg or anti-HCV had higher serum AST and ALT levels than those without HBsAg and anti-HCV. The prevalence of raised ALT and AST (> or =45 IU/liter) in the HCV-positive group was more significant than in the negative group, while that of the HBsAg-positive group did not reach statistical significance. Among the HCV-positive group, ALT levels are more closely associated with HCV infection than AST levels. Our results indicated that HCV infection plays an important role in the etiology of raised ALT activity among drug abusers, while HBV infection plays a minor role. ALT screening still remains a simple and valuable method in the early recognition of HCV infection.

Adolescent↗
PubMed2000

Differences in physician utilization between Aboriginal and non-Aboriginal children.

OBJECTIVE: In the present study, we examined the factors affecting Aboriginal children's visits to a medical practitioner and compared them with non-Aboriginal children. METHODS: We selected five Aboriginal communities and four neighbouring non-Aboriginal communities, and conducted a door-to-door survey, covering all children born after 1983. Of an initial sample of 1013 children, 896 (response rate 89.92% for non-Aboriginal children and 85.87% for Aboriginal children) completed the questionnaire for analysis. RESULTS: In all, 896 children of non-mixed lineage with an age range of 0-12 years were collected into the study, including 316 Aborigines and 580 non-Aborigines. A higher percentage of non-Aboriginal children had more national health insurance coverage than Aboriginal children. The ratio of parents using the services of an out of community medical practitioner when their children were sick was higher for Aboriginal parents than for non-Aborigines. Medical injection frequency was higher in Aboriginal children. Linear regression was used to examine the factors affecting the frequency of physician utilization in the preceding month. CONCLUSION: A lower national health insurance coverage rate, and a higher rate of intramuscular injections for Aboriginal children plus difficulties in access to medical resources due to travel time and travel distance are still major problems for the Aborigines.

Child↗
PubMed2000

Lifetime environmental exposure to tobacco smoke and primary lung cancer of non-smoking Taiwanese women.

BACKGROUND: For a female population with a high lung cancer mortality rate, such as Taiwanese women, who smoke relatively rarely, but live in an environment with high male smoking prevalence, the risk and population burden of lung cancer due to environmental tobacco smoke (ETS) are relatively important. METHODS: An age-matched case-control study was designed to investigate the effects of cumulative environmental exposure to tobacco smoke during childhood and adult life on lung cancer risk among non-smoking women in Taiwan. Information on passive smoking from all possible sources and life periods were obtained from interviews with 268 and 445 lifetime non-smoking cases and controls. Conditional logistic regression and synergism 'S' index were applied to the data to assess the independent and joint effects of passive smoking in different life stages while controlling for possible confounding variables. RESULTS: Risks of contracting lung cancer among women near-distantly exposed to the highest level of ETS in childhood (>20 smoker-years) and in adult life (>40 smoker-years) were 1.8-fold (95% CI: 1.2-2.9) and 2.2-fold (95% CI: 1.4-3.7) higher than that among women being never exposed to ETS, and the two variables accounted for about 37% of tumours in this non-smoking female population. Children were found to be more susceptible to ETS than adults and such early exposure was found to modify the effect of subsequent tobacco smoke exposure in adult life based on an additive interaction model. CONCLUSIONS: Environmental tobacco smoke exposure occurring in childhood potentiates the effect of high doses of exposure in adult life in determining the development of lung cancer. Smoking prohibition would be expected to protect about 37% of non-smoking Taiwanese women against lung cancer.

Adult↗
PubMed2000

Survival rate for liver cancer in Taiwan.

BACKGROUND: There is no nationwide population-based study of the survival rate for liver cancer in Taiwan. Consequently, the true rate of liver cancer survival is unknown. Our aim was to determine the survival rate for liver cancer patients in Taiwan. METHOD: The Taiwan Cancer Registry was searched for liver cancer cases in 1987 and 2,558 cases were found. Of these, 485 lacked an identification number, 29 lacked documentation of age, 33 were metastatic, nine lived in Kinmen and Lienkiang Hsien of Fukien Province leaving 2,002 to be studied. With the help of identification numbers, we linked our cases with the Death Registry of the Department of Health, Executive Yuan, ROC, for the 1987 to 1992 period and calculated the five-year survival rate using actuarial life tables. For analyzing factors affecting the five-year survival rate, multivariate analysis with the Cox proportional hazards model was used. RESULTS: Of the 2,002 patients, 752 were diagnosed histopathologically and 1,250 patients were diagnosed clinically. A total of 15% of patients survived for five years or longer after diagnosis. Of those diagnosed histopathologically, 17% survived for five or more years, and of those diagnosed clinically, 13% survived for five or more years. The sex, age, residential area and ethnic origin did not affect the five-year survival rate significantly. Only diagnosis type affected the five-year survival rate significantly (p < 0.05). The 660 pathologically diagnosed liver cancer patients had a better survival rate than the 1,250 patients diagnosed clinically. CONCLUSIONS: The overall five-year survival rate for liver cancer in Taiwan was 15%. The prognosis for liver cancer patients in Taiwan is still unfavorable. The aim is to persuade affected patients to accept treatment.

Adolescent↗