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Biomedical subjects

Yueliang Leon Guo

Publications and source records attributed to Yueliang Leon Guo.

At least 19 recordsLinked to original sources

Chinese herbal medicines used in pregnancy: a population-based survey in Taiwan.

PURPOSE: To explore the use (prevalence and related factors) of Chinese herbal medicines used by pregnant women. METHODS: We used multistage stratified systematic sampling to recruit 2048 postpartum women from the Taiwan national birth register between November and December 2003. Subjects underwent a home interview 6 months after their deliveries. A structured questionnaire was successfully applied to 87% of the sampled population. RESULTS: At least one Chinese herbal medicine was used during pregnancy by 24.1% of the interviewed subjects. Pregnant women with threatened abortion appeared to use more Chinese herbal medicines than other pregnant women. CONCLUSION: Chinese herbal medicines are frequently used by pregnant women in Taiwan and are very frequently used by those with a threatened abortion.

Abortion, Threatened↗

A comparison of PCDD/PCDFs exposure in infants via formula milk or breast milk feeding.

Food is the major source for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulation in human body. In infant period, breast milk and formula milk are the major food sources. Congener-specific analyses of 17 PCDD/PCDFs were performed on 10 brands of formula milk samples which were milk-based and 37 breast milk samples collected from women living in southern Taiwan. The levels of 17 PCDD/PCDFs in 10 formula milk samples ranged from 0.468 to 0.962 pg WHO-TEQ/g lipid, with a mean value of 0.713+/-0.163 pg WHO-TEQ/g lipid. For the 37 breast milk samples, their PCDD/PCDF levels were 14.7+/-9.36 pg WHO-TEQ/g lipid, with a range between 4.21 and 52.8 pg WHO-TEQ/g lipid. At 12th month of age for infants, average daily intakes (ADI) of PCDD/PCDFs were 2.1 pg WHO-TEQ/kg/day for the formula-feeding infants, and 13 pg WHO-TEQ/kg/day for the breast-feeding infants. The present data may provide useful information for risk-benefit evaluation of formula- and breast-feeding.

Animals↗

Genetic polymorphisms in CYP1A1 and GSTM1 predispose humans to PCBs/PCDFs-induced skin lesions.

INTRODUCTION: Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are ubiquitous persistent pollutants in humans. Whether people with different genotypes are with different susceptibility to these chemicals are unknown. In a group of people highly exposed to PCBs/PCDFs, we tested the hypothesis that genotypic polymorphisms affected susceptibility for development of skin manifestations. METHODS: In 1979, approximately 2000 people in central Taiwan ingested cooking oil contaminated with PCBs/PCDFs. Skin disorder such as chloracne, abnormal nail, hyperkeratosis and skin allergy were found in PCBs/PCDFs exposed group. We recruited exposed and community background exposure subjects for blood testing and telephone-interview. Single nucleotide polymorphisms, AhR Arg554Lys, CYP1A1 Ile462Val, CYP1A1 T6235C, and GSTM1/T1 deletion, were determined. Occurrence of skin manifestations was compared among people with different genotypes while stratified by PCB exposure levels by logistic regression. RESULTS: Data on exposure, medical history, and genotypes were obtained from 393 exposed and 181 background exposure groups. Skin manifestations including chloracne, allergy, abnormal nail, and hyperkeratosis were more prevalent in exposed people in a dose-related manner. Among highly exposed individuals, combined CYP1A1-MspI mutant genotype and GSTM1-null genotype were associated with increased risk of chloracne (odds ratio 2.8, 95% confidence interval 1.1-7.6). Among intermediately exposed individuals, GSTM1 null genotype was associated with skin allergy. AhR Arg554Lys genotype and GSTT1 null genotype were not related to susceptibility to skin manifestations in PCB/PCDF-exposed population. CONCLUSION: CYP1A1 and GSTM1 genotypic polymorphisms might be related to the susceptibility to PCB/PCDF-induced skin manifestations.

Adult↗

Association between cord blood IgE and genetic polymorphisms of interleukin-4, the beta-subunit of the high-affinity receptor for IgE, lymphotoxin-alpha, and tumor necrosis factor-alpha.

High cord blood immunoglobulin E (cbIgE) is known to be associated with increased risks of atopic diseases in childhood. The relationship between genetic polymorphisms and high cbIgE has not been well documented. A cross-sectional study was conducted to assess the association between cbIgE and genetic polymorphisms of interleukin (IL)-4 -590C/T, the beta-subunit of the high-affinity receptor for IgE (FcepsilonRI-beta) E237G, lymphotoxin (LT)-alphaNcoI alleles, and tumor necrosis factor (TNF)-alpha -308G/A. A total of 320 mother-neonate pairs were recruited from four maternity hospitals from different locations of Taiwan. Cord blood was obtained and assayed for cbIgE. Polymerase chain reaction followed by restriction fragment length polymorphism was used to assess the genotypes. Three hundred pairs of mothers and neonates were included in the final analysis. Infants with IL-4 -590 C allele were found to have higher risk of elevated cbIgE (> or =0.35 IU/ml, 24.3%) (p = 0.004). After adjusting for gender, birth order, maternal age, and history of allergic disease in maternal and paternal families, odds ratios for CC and CT genotypes were 4.41 and 3.16 (95% confidence interval 0.78-22.67, and 1.66-6.13), respectively, using TT genotype as reference. The genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha were not associated with cbIgE before or after the adjustment. Our finding suggested a significant association of cbIgE with genetic polymorphism of IL-4 -590C/T, but not with the genotypes of FcepsilonRI-beta, LT-alpha, and TNF-alpha.

Cohort Studies↗

Home exposures, parental atopy, and occurrence of asthma symptoms in adulthood in southern Taiwan.

OBJECTIVE: Parental atopy and environmental exposures at home have been recognized risk factors for adulthood asthma. However, the relative contributions of specific risk factors and the overall contributions of heredity or home exposure remain unexplored. The purpose of this study was to identify predictors and estimate the population attributable risk (PAR) of each exposure for typical asthma symptoms among 26- to 50-year-old Taiwanese. We also investigated whether an interactive effect existed between parental atopy and home exposures on the occurrence of asthma symptoms in adulthood. DESIGN: A cross-sectional study with retrospective components. SETTING: Elementary and middle schools in Southern Taiwan. SUBJECTS: Between March and October 2004, we conducted a cross-sectional survey among schoolchildren's parents from 94 elementary and middle schools in Southern Taiwan. The main outcome measure was typical asthma-like symptoms occurring within the preceding 5 years. Information on hereditary and home exposures was collected by using a self-administered questionnaire. RESULTS: After excluding unqualified questionnaires, data from 24,784 subjects were left for analysis. New-onset asthma was reported for 0.83% of male (n = 80 of 9,662) and 1.36% of female subjects (n = 206 of 15,122). Besides parental atopic factors, environmental tobacco smoke or pet avoidance and visible mold on walls at home were independently associated with the occurrence of asthma symptoms. Mutually adjusted models produced statistically significant associations between any home exposure (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.08 to 3.23; PAR, 28.04%), parental atopy (OR, 4.47; 95% CI, 3.47 to 5.75; PAR, 31.38%), and new-onset asthma. However, there was no interaction between parental atopy and home exposures. CONCLUSIONS: Home exposures and parental atopy both increased the risks of new-onset asthma in adulthood but did not show an interactive effect. These two exposure categories approximately contributed equally to the adulthood asthma.

Adult↗

The endocrine and reproductive function of the female Yucheng adolescents prenatally exposed to PCBs/PCDFs.

BACKGROUND: Polychlorinated biphenyls (PCBs) and related compounds such as polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-dioxins (PCDDs) alter sexual maturation and endocrine function in animals. In 1978-1979, a mass poisoning occurred in central Taiwan from cooking oil contaminated by heat-degraded PCBs and oxidated compounds PCDFs. We tested the hypothesis that in utero exposed to PCBs/PCDFs alter sexual maturation, endocrine, and reproductive function in the human pubescent females. METHODS: In 1997-1999, girls aged 13-19 years, born to mothers exposed to PCBs/PCDFs, was invited to participate in the study. Menstruation characteristic was recorded daily for 84 days and serum levels of estradiol, LH, FSH, and testosterone were measured on the 3rd day of menstruation. RESULTS: A total of 17 exposed girls and controls participated, the exposed girls reported shorter mean duration of bleeding per cycle than 16 unexposed (5.5 vs 6.5 days, P=0.0055). There was a higher rate of irregular menstrual cycle in the exposed girls (40% vs 0%, P=0.018). Serum levels of estradiol (P=0.016) and FSH (P=0.061) were higher in exposed girls as compared to controls. CONCLUSIONS: We conclude that prenatal exposure to PCBs/PCDFs resulted in abnormal menstruation and higher estradiol and FSH levels in follicular phase of menstrual cycle in adolescent girls.

Adolescent↗

Serum hormones in boys prenatally exposed to polychlorinated biphenyls and dibenzofurans.

Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are persistent environmental pollutants shown to adversely interact with several functions of the endocrine system. In 1978-1979, over 2000 Taiwanese people ingested rice oil accidentally contaminated with PCBs and PCDFs. This is one of the major toxic exposure episodes that occurred globally and was later called Yucheng (oil disease in Chinese). The children born to exposed Yucheng women were therefore exposed in utero to high doses of PCBs/PCDFs. In 1995, 60 Yucheng and 61 control boys participated in physical examination, and serum hormones were measured by radioimmunoassay (RIA). Age, body weight, body height, Tanner status, testicular size, serum luteinizing hormone (LH), prolactin (PRL), thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) levels were not statistically different between Yucheng and control boys in the subgroups of before and at the age of puberty. However, the serum estradiol (E2) levels were significant higher in Yucheng boys at the age of puberty. Yucheng and control boys were further divided into two subgroups, those before (age <13 yr) and those at the age of puberty (age > or = 13 yr). There was a decrease of serum testosterone (TT) levels and increase of serum follicle-stimulating hormone (FSH) levels in Yucheng boys at the age of puberty as compared with controls. There was a significant decrease of the square root of TT/E2 and TT/FSH; however, the square root of E2/FSH was increased in Yucheng boys at the age of puberty as compared with controls. Data indicated that prenatal exposure to PCBs and PCDFs may have implications for boys' sex hormone homeostasis at puberty. Further studies are needed to identify the congeners of PCBs/PCDFs responsible for disruption of the endocrine system, as well as the mechanisms of such disruption.

Adolescent↗

Changing prevalence of asthma in Taiwanese adolescents: two surveys 6 years apart.

This study compared the prevalence of asthma among Taiwanese adolescents with individual-level risk factors and municipal-level air pollution and meteorology data to determine whether changes in these factors could explain the observed change in prevalence. We conducted two national surveys of respiratory illness and symptoms in Taiwanese middle-school students in 1995-96 and 2001. The effects of personal and environmental factors were assessed and temporal changes of outdoor monitoring data were also compared with asthma prevalence difference. A total of 44,104 children from the 1995-96 survey and 11,048 children from the 2001 survey attended schools located within 1 km of 22 monitoring stations. Lifetime prevalences of physician-diagnosed and questionnaire-determined asthma increased during this period. After adjustment for potential risk factors, the prevalence differences were statistically unchanged. Although parental education level contributed most, changes in investigated personal and environmental factors might not explain the observed changes in asthma prevalence. Municipalities with higher temperature increase were significantly associated with prevalence difference in questionnaire-determined asthma. We concluded that correlates of the investigated individual-level factors, which have changed over time, still underlie changes in asthma prevalence. Increasing temperature might be the main reason for the rising trends of asthma in Taiwanese adolescents.

Adolescent↗

The association between glutathione S-transferase P1, M1 polymorphisms and asthma in Taiwanese schoolchildren.

STUDY OBJECTIVES: Genetic polymorphisms in the glutathione S-transferase P1 gene (GSTP1) and the glutathione S-transferase M1 gene (GSTM1) have been implicated as risk factors for asthma. However, their roles in asthma pathogenesis and the interaction between these two genes have not been extensively investigated. This study, therefore, examined the relationship among GSTP1 and GSTM1 genotypes and childhood asthma, and evaluated their gene-gene interactions. SETTING: The population from three southern Taiwan communities of a 2001 national survey. SUBJECTS AND METHODS: Two hundred sixty-six fourth-grade to ninth-grade schoolchildren were recruited for oral mucosa samplings based on questionnaire information. Polymerase chain reaction-based assays were performed to determine GSTP1 and GSTM1 genotypes among asthmatic subjects and nonasthmatic control subjects. Multiple logistic regression was used to adjust for potential confounding factors. RESULTS: All of the participants were homozygous at the GSTP1 Ala-114 locus. After controlling for age, sex, and atopic eczema, compared with participants carrying any Val-105 allele, children who were homozygotic for GSTP1 Ile-105 had a significantly increased risk of physician-diagnosed asthma (adjusted odds ratio [adjOR], 1.94; 95% confidence interval [CI], 1.08 to 3.59). A positive risk for childhood asthma was also noted on the GSTM1 null genotype but did not reach statistical significance (adjOR, 1.37; 95% CI, 0.80 to 2.38). Among children with GSTM1 present genotypes, GSTP1-105 polymorphisms were associated with the increased risk of asthma. However, the reduced and statistically insignificant asthma risk was observed among those with GSTM1 null genotype. CONCLUSIONS: We concluded that GSTP1-105 was a predictor for childhood asthma, whereas GSTM1 polymorphism might modify the risk. Our study also suggested a competitive effect for homozygous GSTP1 Ile-105 and GSTM1 null genotypes on childhood asthma.

Asthma↗

Occupational stress in nurses in psychiatric institutions in Taiwan.

Nurses are known to be exposed to occupational stress. However, occupational stress is not well documented for nurses in psychiatric institutions in Taiwan. A cross-sectional study was conducted to explore the work-related stress and risk factors of nurses in psychiatric institutions in Taiwan. A structured questionnaire was distributed to nurses at five state-owned psychiatric hospitals in Taiwan in 2001. Demographic information, working environment, and personal health status were inquired. Occupational stress was assessed based on the Chinese version of Job Content Questionnaire (JCQ). General health status and mental health were evaluated by the International Quality of Life Assessment Short Form-36 (IQOLA SF-36). A total of 573 questionnaires were disseminated to nurses and 518 (90.4%) were satisfactorily completed by nurses, including 408 female full-time nurses who had been in their current work for more than 6 months. In the past one month, 17.2% of nurses reported being under significant stress often or always. Assault episodes were reported by 45.1% of nurses in the past 6 months. Among the nurses, 16.9%, 25.2%, 50.0%, and 7.8% belong to the "High strain", "Low strain", "Active", and "Passive" groups, respectively. Perceived occupational stress was associated with young age, widowed/divorced/separated marital status, high psychological demand, low workplace support, and threat of assault at work. Lower general health score was associated with low job control, high psychological demand, and perceived occupational stress. A lower mental health score was associated with low job control, high psychological demand, low workplace support, and perceived occupational stress. We concluded that nurses in psychiatric institutions are under significant stress related to work factors.

Adult↗

Infant exposure to polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs)--correlation between prenatal and postnatal exposure.

Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are recognized environmental endocrine disruptors, which are environmentally persistent and may bio-accumulate in human bodies. Pregnant and nursing women may pass these pollutants to their babies both trans-placentally and lactationally. We measured and examined correlations of the levels of PCDD/Fs and PCBs in perinatal venous serum, placenta, umbilical-cord serum (representing prenatal exposure), and breast milk (postnatal exposure). Subjects included pregnant women without clinical complication between the ages of 25 and 35, who delivered their babies during 2000.12.01 and 2001.11.30 in central Taiwan. A total of 20 participants were randomly selected from those provided the four biological specimens for analysis of 17 PCDD/Fs, and 12 dioxin-like PCBs and six indicator PCBs using high-resolution gas chromatography/high-resolution mass spectrometry. Higher PCDD/F levels were found in placenta (10.3 TEq-pg/g lipid) and venous serum (9.1 TEq-pg/g lipid) compared to those in breast milk (7.6 TEq-pg/g lipid). Pearson and Spearman correlation analyses showed well association of PCDD/F and PCB levels between different specimens. The total dioxin/PCB level in milk, venous and cord serum can be well predicted by that in placenta through regression functions. This first study of multi-specimen correlation further established rather consistent ratios of these chemical concentrations in various specimens relative to those in venous serum.

Benzofurans↗

Effects of acute postnatal exposure to 3,3',4,4'-tetrachlorobiphenyl on sperm function and hormone levels in adult rats.

Polychlorinated biphenyls (PCBs) are considered potential endocrine disruptors due to their ability to act as estrogens, antiestrogens and goitrogens. The aim of this study is to ascertain whether acute postnatal treatment with 3,3',4,4'-tetrachlorobiphenyl (CB 77) affects sperm function and hormone levels in adult rats. Male Sprague-Dawley rats received CB 77 by ip injection of 2 or 20 mg/kg at day 21 and sacrificed at day 112. At day 112, right and left testis weights were significantly increased, whereas sperm count, motility, total motile sperm count, curvilinear velocity, average path velocity, straight-line velocity, and beat-cross frequency for motile sperm were significantly decreased in rats treated with 20 mg/kg CB 77. Sperm-oocyte penetration rate was significantly reduced in rats treated with either 2 or 20 mg/kg CB 77. There was high sperm acrosome reaction rate (ARR) in the 20 mg/kg CB 77-treated rats. There was a significant increase in thyroid-stimulating hormone level in the 20 mg/kg CB 77 group. However, no changes were seen in serum testosterone, thyroid hormones, or prolactin concentrations at day 112. In summary, this study showed that postnatal exposure to CB 77 might affect spermatogenesis, motility, ARR, and ability of fertilizing oocytes in mature rats. These results suggest that the sperm functions may be more susceptible or adapt less readily than the thyroid functions to endocrine disruption caused by dioxin-like PCB congeners.

Analysis of Variance↗

Sperm function in workers exposed to N,N-dimethylformamide in the synthetic leather industry.

OBJECTIVE: To determine whether occupational exposure to N,N-dimethylformamide (DMF) for men has adverse effects on sperm function. DESIGN: Cross-sectional study. SETTING: A synthetic leather factory in Taiwan. PATIENT(S): Twelve DMF-exposed workers in a synthetic leather factory and 8 socioeconomically matched control workers from another non-DMF-exposed manufacturing plant in the vicinity were recruited. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Breathing-zone monitoring of DMF exposure covering the full work shift was implemented on each participant. Urine specimens were collected from each worker immediately after their work shift in parallel with environmental sampling. Environmental DMF and urinary N-methylformamide (NMF) levels were measured by gas chromatograph. Analysis of semen samples was performed to measure semen volume, sperm concentration, morphology, and motility in accordance with World Health Organization criteria. RESULT(S): Both conventional microscopy and computer-assisted semen analysis showed that sperm motility in DMF-exposed group was significantly reduced from that in controls. Motility parameters were related to urinary NMF in a dose-response manner but were not related to airborne DMF. CONCLUSION(S): Workers occupationally exposed to DMF could be at risk of sperm motility perturbation. The responsible toxicant for the alterations of sperm function could be the active NMF metabolite instead of DMF, but this conclusion warrants a further complete investigation.

Adult↗

Prevalence and risk factors of occupational hand dermatoses in electronics workers.

The electronics industry is becoming an important mainstream in the workforce in some developed countries and in Taiwan. Among patients with occupational hand dermatitis in northern Taiwan, workers from electronics industries were one of the most important groups. We conducted a field investigation to determine the prevalence, patterns and risk factors of occupational hand dermatoses among electronics workers. The survey was conducted in five electronics plants using a self-administered questionnaire on skin symptoms and risk factors. Skin examination and patch testing were followed for those with symptoms compatible with hand dermatitis. A total of 3070 workers completed the questionnaire. Among them, 302 (9.8%) reported to have symptoms (itching and with either redness/scaling) compatible with contact dermatitis on hands. Hand dermatitis was associated with working in the fabrication unit and personal history of atopy and metal allergy, as well as the following job titles: wafer bonding, cutting, printing/photomasking, softening/degluing, impregnation and tin plating. Among those with reported hand dermatitis, 183 completed skin examination and patch testing, 65/183 (35.5%) were diagnosed as having irritant contact dermatitis (ICD) and 7/183 (3.8%) allergic contact dermatitis. The most important allergens were nickel, cobalt and phenylenediamine. In conclusion, Taiwanese electronics workers have a high risk of having hand dermatitis, especially ICD. Preventive efforts should be focused on the workers with risk factors or at certain worksites.

Adolescent↗

Occupational health research in Taiwan.

This article gave a brief introduction of population, labor force, general status of occupational safety and health in Taiwan. Statistics of occupational injuries and health disorders, laws and regulations relevant to occupational health were also covered. Research activities driven by universities, research institutes, society/association were provided. Two multi-lateral collaborative research examples were presented: an intoxication outbreak-initiated CS2 study and an information-demand-motivated 2-methoxy-ethanol study. Industrial hygienists, engineers, epidemiologists, and occupational physicians from both universities and research institutes, governmental agencies, and from non-profit R&D organizations and academic associations were involved in these researches, presenting a promise that integrated collaboration of inter-disciplinary specialty cooperated with governmental participation could benefit not only academic achievement, governmental policy-makeup, but also to the employees themselves.

Animals↗

Differential UVC-induced gadd45 gene expression in xeroderma pigmentosum cells.

Xeroderma pigmentosum C (XPC) is a DNA repair factor essential for global genome repair (GGR) in nucleotide excision repair (NER). In the present study we screened for factors regulated by XPC after DNA damage. Ultraviolet C (UVC) irradiation-induced stress response factors were analyzed by a cDNA microarray chip system in HeLa and XP4PA-SV xpc mutant cell lines. The principal component analysis (PCA) method was employed to identify groups of genes with similar expression patterns over time after UVC irradiation. The growth arrest and DNA damage-inducible gene gadd45, as well as a small group of other genes, was found to exhibit an inducible expression pattern after 30min of incubation in xpc mutants but not in HeLa cells. Subsequent studies showed that gadd45 gene expression post-UVC irradiation was also present in the GGR mutant cells xpa and xpd, but not in TCR mutant csb cells. This evidence indicates that gadd45 plays a regulatory role in GGR of NER.

Cell Line↗

Postnatal exposure of 2,2',3,3',4,6'-hexachlorobiphenyl and 2,2',3,4',5',6-hexachlorobiphenyl on sperm function and hormone levels in adult rats.

Polychlorinated biphenyls (PCBs) are known to affect reproductive system in animals and in accidentally or occupationally exposed humans. Information is lacking on effects of non-dioxin like chlorinated biphenyls (CB) congeners on male reproduction. The aim of this study is to determine whether treatment of postnatal non-dioxin like CB congeners affects sperm function and hormone levels in rats. Male Sprague-Dawley rats received either 2,2',3,3',4,6'-hexachlorobiphenyls (CB 132) or 2,2',3,4',5',6-hexachlorobiphenyls (CB 149) by ip injection of 9.6 or 96 mg/kg at day 21. At 16 weeks, the animals were sacrificed; sperm quality and hormone levels were measured. Body weight, testis and cauda epididymis weights, sperm counts, ROS generation, acrosome reaction rate, serum thyroxine (T(4)), free T(4) and testosterone (TT) concentrations were unaffected. However, treatment of CB 132 and CB 149 caused decreases in sperm motility, curvilinear velocity (VCL), average path velocity (VAP), straight-line velocity (VSL), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF). Serum triiodothyronine (T(3)) level was significantly decreased in CB 132 9.6 mg/kg dose group compared with the controls. On the other hand, a significant decrease was found in free T(3) concentration both in 96 mg/kg of CB 132 and CB 149 groups. In summary, this study showed that CB 132 and CB 149 affects serum levels of triiodothyronine as well as sperm motility, velocity and capability of penetrating oocytes. The mechanism of action and potential effects on human warrant further investigation.

Animals↗