Sex differences in the transcriptome of extracellular vesicles secreted by fetal neural stem cells and effects of chronic alcohol exposure

BACKGROUND

Prenatal alcohol (ethanol) exposure (PAE) results in brain growth restriction, in part, by reprogramming self-renewal and maturation of fetal neural stem cells (NSCs) during neurogenesis. We recently showed that ethanol resulted in enrichment of both proteins and pro-maturation microRNAs in sub-200-nm-sized extracellular vesicles (EVs) secreted by fetal NSCs. Moreover, EVs secreted by ethanol-exposed NSCs exhibited diminished efficacy in controlling NSC metabolism and maturation. Here we tested the hypothesis that ethanol may also influence the packaging of RNAs into EVs from cell-of-origin NSCs.

METHODS

Sex-specified fetal murine iso-cortical neuroepithelia from three separate pregnancies were maintained ex vivo, as neurosphere cultures to model the early neurogenic niche. EVs were isolated by ultracentrifugation from NSCs exposed to a dose range of ethanol. RNA from paired EV and cell-of-origin NSC samples was processed for ribosomal RNA-depleted RNA sequencing. Differential expression analysis and exploratory weighted gene co-expression network analysis (WGCNA) identified candidate genes and gene networks that were drivers of alterations to the transcriptome of EVs relative to cells.

RESULTS

The RNA content of EVs differed significantly from cell-of-origin NSCs. Biological sex contributed to unique transcriptome variance in EV samples, where > 75% of the most variant transcripts were also sex-variant in EVs but not in cell-of-origin NSCs. WGCNA analysis also identified sex-dependent enrichment of pathways, including dopamine receptor binding and ectoderm formation in female EVs and cell-substrate adhesion in male EVs, with the top significant DEGs from differential analysis of overall individual gene expressions, i.e., Arhgap15, enriched in female EVs, and Cenpa, enriched in male EVs, also serving as WCGNA hub genes of sex-biased EV WGCNA clusters. In addition to the baseline RNA content differences, ethanol exposure resulted in a significant dose-dependent change in transcript expression in both EVs and cell-of-origin NSCs that predominantly altered sex-invariant RNAs. Moreover, at the highest dose, ~ 73% of significantly altered RNAs were enriched in EVs, but depleted in NSCs.

CONCLUSIONS

The EV transcriptome is distinctly different from, and more sex-variant than, the transcriptome of cell-of-origin NSCs. Ethanol, a common teratogen, results in dose-dependent sorting of RNA transcripts from NSCs to EVs which may reprogram the EV-mediated endocrine environment during neurogenesis.

Toxic and Teratogenic Effects of Prenatal Alcohol Exposure on Fetal Development, Adolescence, and Adulthood

Prenatal alcohol exposure (PAE) can have immediate and long-lasting toxic and teratogenic effects on an individual’s development and health. As a toxicant, alcohol can lead to a variety of physical and neurological anomalies in the fetus that can lead to behavioral and other impairments which may last a lifetime. Recent studies have focused on identifying mechanisms that mediate the immediate teratogenic effects of alcohol on fetal development and mechanisms that facilitate the persistent toxic effects of alcohol on health and predisposition to disease later in life. This review focuses on the contribution of epigenetic modifications and intercellular transporters like extracellular vesicles to the toxicity of PAE and to immediate and long-term consequences on an individual’s health and risk of disease.

Risk of Myocardial Infarction and Ischemic Stroke after Dental Treatments

The association between invasive dental treatments (IDTs) and a short-term risk of myocardial infarction (MI) and ischemic stroke (IS) remains controversial. Bacterial dissemination from the oral cavity and systemic inflammation linked to IDT can induce a state of acute vascular dysfunction. The aim of study is to investigate the relation of IDTs to MI and IS by using case-only study designs to analyze data from a large Taiwanese cohort. A nationwide population-based study was undertaken by using the case-crossover and self-controlled case series design to analyze the Taiwanese National Health Care Claim database. Conditional logistic regression model and conditional Poisson regression model were used to estimate the risks of MI/IS. In addition, we used burn patients as negative controls to explore the potential effect of residual confounding. In total, 123,819 MI patients and 327,179 IS patients in the case-crossover design and 117,655 MI patients and 298,757 IS patients were included in the self-controlled case series design. Results from both study designs showed that the risk of MI within the first 24 wk after IDT was not significantly different from or close to unity except for a modest risk during the first week for patients without other comorbidities (odds ratios [95% confidence intervals] of 1.31 [1.08-1.58] and 1.15 [1.01-1.31] for 3 d and 7 d, respectively). We also observed no association between IDTs and IS, or the risk ratio was close to unity. IDTs did not appear to be associated with a transient risk of MI and IS in the Taiwanese population, with consistent findings from both case-only study designs. However, we cannot exclude that dental infections and diseases may yield a long-term risk of MI and IS.

Historical epidemiology of hepatitis C virus in select countries-volume 4

Due to the introduction of newer, more efficacious treatment options, there is a pressing need for policy makers and public health officials to develop or adapt national hepatitis C virus (HCV) control strategies to the changing epidemiological landscape. To do so, detailed, country-specific data are needed to characterize the burden of chronic HCV infection. In this study of 17 countries, a literature review of published and unpublished data on HCV prevalence, viraemia, genotype, age and gender distribution, liver transplants and diagnosis and treatment rates was conducted, and inputs were validated by expert consensus in each country. Viraemic prevalence in this study ranged from 0.2% in Hong Kong to 2.4% in Taiwan, while the largest viraemic populations were in Nigeria (2 597 000 cases) and Taiwan (569 000 cases). Diagnosis, treatment and liver transplant rates varied widely across the countries included in this analysis, as did the availability of reliable data. Addressing data gaps will be critical for the development of future strategies to manage and minimize the disease burden of hepatitis C.

The present and future disease burden of hepatitis C virus infections with today's treatment paradigm: Volume 4

Factors influencing the morbidity and mortality associated with viremic hepatitis C virus (HCV) infection change over time and place, making it difficult to compare reported estimates. Models were developed for 17 countries (Bahrain, Bulgaria, Cameroon, Colombia, Croatia, Dominican Republic, Ethiopia, Ghana, Hong Kong, Jordan, Kazakhstan, Malaysia, Morocco, Nigeria, Qatar and Taiwan) to quantify and characterize the viremic population as well as forecast the changes in the infected population and the corresponding disease burden from 2015 to 2030. Model inputs were agreed upon through expert consensus, and a standardized methodology was followed to allow for comparison across countries. The viremic prevalence is expected to remain constant or decline in all but four countries (Ethiopia, Ghana, Jordan and Oman); however, HCV-related morbidity and mortality will increase in all countries except Qatar and Taiwan. In Qatar, the high-treatment rate will contribute to a reduction in total cases and HCV-related morbidity by 2030. In the remaining countries, however, the current treatment paradigm will be insufficient to achieve large reductions in HCV-related morbidity and mortality.

Strategies to manage hepatitis C virus infection disease burden-Volume 4

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 17 countries in Africa, Asia, Europe, Latin America and the Middle East, and interventions for achieving the Global Health Sector Strategy on viral hepatitis targets-"WHO Targets" (65% reduction in HCV-related deaths, 90% reduction in new infections and 90% of infections diagnosed by 2030) were considered. Scaling up treatment and diagnosis rates over time would be required to achieve these targets in all but one country, even with the introduction of high SVR therapies. The scenarios developed to achieve the WHO Targets in all countries studied assumed the implementation of national policies to prevent new infections and to diagnose current infections through screening.

Can aspirin reduce the risk of colorectal cancer in people with diabetes? A population-based cohort study

AIM

To evaluate whether aspirin can reduce the risk of colorectal cancer in people with diabetes.

METHODS

We studied ≥ 30-year-old people with diabetes, included in the Longitudinal Health Insurance Database 2005 in Taiwan, who were treated with hypoglycaemic drugs. We used a time-varying Cox regression model to adjust for immortal time bias and to estimate the adjusted hazard ratio and 95% CI for the association between aspirin use and colorectal cancer occurrence.

RESULTS

We studied a total of 60 828 people with diabetes (31 176 men and 29 652 women). Their mean (sd) age was 58.72 (13.33) years. A total of 26 494 people were taking aspirin. Aspirin use 3-5 times/week (moderate frequency) for > 5 years (long duration) was found to reduce the risk of colorectal cancer by 46% (hazard ratio 0.54, 95% CI 0.34-0.86). Aspirin use > 5 times/week (high frequency) for 4-5 years (moderate duration) and > 5 years reduced the risk of colorectal cancer by 56 and 68%, respectively (hazard ratio 0.44, 95% CI 0.24-0.80; hazard ratio 0.32, 95% CI 0.20-0.50). Low frequency (≤ 2 times/week) and/or short duration (≤ 3 years) of aspirin use did not reduce the risk of colorectal cancer.

CONCLUSIONS

Aspirin use with high frequency and long duration reduced the risk of colorectal cancer in people with diabetes in a frequency- and duration-dependent manner, whereas low frequency and/or short duration of aspirin use did not. The dosage, frequency and duration of aspirin use that are sufficient to prevent the incidence of colorectal cancer in people with diabetes require further study.

Nationwide population-based epidemiologic study of rheumatoid arthritis in Taiwan

OBJECTIVES

Epidemiological studies of rheumatoid arthritis in Asia are rare. The aim of this research was to study the epidemiology and associated medical expenses of rheumatoid arthritis in Taiwan.

METHODS

Cases of rheumatoid arthritis, based on the 1987 American College of Rheumatology criteria, were retrieved from the National Health Insurance Research Database with corresponding International Classification of Diseases, Ninth Revision code (ICD-9) 714.0 from January 2000 to December 2007, and limited to those 16 years and older. Age- and sex-specific incidences were estimated by dividing the incidence number by population data obtained from the Department of Statistics, Ministry of the Interior.

RESULTS

There were a total of 40,995 cases. The average age-adjusted annual incidence rate was 15.8 per 100,000. The adjusted incidence rates were very stable at 20.9-25.2/100,000/year and 7.0-8.2/100,000/year for females and males, respectively, during the study period. The adjusted average incidence ratio of females/males was 3.1. The age-specific incidence peaked in the 60-64 and 70-74 year age groups for females and males, respectively. The adjusted prevalence rate increased steadily during the study period from 57.7/100,000 in 2000 to 99.6/100,000 in 2007. The average total yearly expense per patient increased from 1,155 United States Dollars (USD) in 2000 to 1,821 USD in 2007. Sicca syndrome (ICD-9 code 710.2) was the most common co-existing ICD-9 code.

CONCLUSIONS

This is the first incidence study based on the 1987 American College of Rheumatology criteria in Asia. The prevalence rate based on these criteria was lower than in previous Asia studies. The medical expenses increased continuously.

A randomised controlled study of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced acute dystonia or parkinsonism

The objective of this study was to compare the effects of risperidone and olanzapine in schizophrenic patients with intolerant extrapyramidal side effects (EPS) on first generation antipsychotics. We conducted an 8-week, rater-blinded, flexible dose study. Seventy patients with schizophrenia, who met the DSM-IV research criteria of having neuroleptic-induced acute dystonia or parkinsonism, were randomly assigned to risperidone or olanzapine group. The primary outcome was a comparison of the incidence of concomitant anticholinergic drugs usage between the groups to manage their acute dystonia and parkinsonism. The average doses of risperidone and olanzapine from baseline to study end point were 1.8-3.5 mg/day and 7.7-11.7 mg/day, respectively. There were no significant differences in demographic data, severity of EPS or psychotic symptoms between the groups at baseline assessment. Patients taking risperidone had significantly higher incidence of using anticholinergic drugs to manage acute dystonia or parkinsonism overall during the study (OR = 5.17, 95%CI = 1.49-17.88, P = 0.013). There was no significant between-group difference in the changing of rating scales of EPS and psychotic symptoms. The results of our study favour olanzapine as a better choice in schizophrenic patients with intolerant EPS. Double-blinded, fixed dose and different ethnical study for EPS-intolerant schizophrenic patients is needed to confirm the results of our study.

Influence of solution acidity and CaCl2 concentration on the removal of heavy metals from metal-contaminated rice soils

Soil washing is considered a useful technique for remediating metal-contaminated soils. This study examined the release edges of Cd, Zn, Ni, Cr, Cu or Pb in two contaminated rice soils from central Taiwan. The concentrations exceeding the trigger levels established by the regulatory agency of Taiwan were Cu, Zn, Ni and Cr for the Ho-Mei soil and Pb for the Nan-Tou soil. Successive extractions with HCl ranging from 0 to 0.2 M showed increased release of the heavy metals with declining pH, and the threshold pH value below which a sharp increase in the releases of the heavy metals was highest for Cd, Zn, and Ni (pH 4.6 to 4.9), intermediate for Pb and Cu (3.1 to 3.8) and lowest for Fe (2.1), Al (2.2) and Cr (1.7) for the soils. The low response slope of Ni and Cr particularly for the rice soils make soil washing with the acid up to the highest concentration used ineffective to reduce their concentrations to below trigger levels. Although soil washing with 0.1 M HCl was moderately effective in reducing Cu, Pb, Zn and Cd, which brought pH of the soils to 1.1+/-0.1 (S.D.), the concurrent release of large quantities of Fe and Al make this remediation technique undesirable for the rice soils containing high clay. Successive washings with 0.01 M HCl could be considered an alternative as the dissolution of Fe and Al was minimal, and between 46 to 64% of Cd, Zn, and Cu for the Ho-Mei soil and 45% of Pb in the Na-Tou soil were extracted after four successive extractions with this dilute acid solution. The efficacy of Cd extraction improved if CaCl2 was added to the acid solution. The correlation analysis revealed that Cr extracted was highly correlated (P < 0.001) with Fe extracted, whereas the Cu, Ni, Zn, Cd or Pb extracted was better correlated (P < 0.001) with Al than with Fe extracted. It is possible that the past seasonal soil flooding and drainage in the soils for rice production was conducive to incorporating Cr within the structure of Fe oxide, thereby making them extremely insoluble even in 0.2 M HCl solution. The formation of solid solution of Ni with Al oxide was also possible, making it far less extractable than Cd, Zn, Cu, or Pb with the acid concentrations used.

Post-radiation Pap smear for Chinese patients with cervical cancer: a ten-year follow-up

BACKGROUND

To study the performance of routine follow-up Pap smears after curative radiotherapy (RT) for Chinese cervical cancer (CC) patients.

METHODS

In 1996, 50 patients with non-metastatic CC received curative RT. Forty-six patients had routine follow-up Pap smears and constituted the study group. Details regarding clinical characteristics were retrospectively abstracted. Pap smear results were obtained via national Pap smear database linkage and chart review. The Pap smear results during recurrence-free survival (RFS) were analyzed and compared with clinical outcomes to study the performance characteristics.

RESULTS

After 34 (2 approximately 105) months' median follow-up, the clinical outcomes were isolated central recurrence (ICR), other recurrence (OR), and no evidence of disease (NED) for six, 20, and 20 patients, respectively. During 22 months' median RFS (range 2-105), 422 Pap smears (including missing data, n = 33) were performed. Most of the Pap smear results were within normal limits (65.8%) or benign (reactive changes or atrophy with inflammation) (25.2%). Atypical cells, low-grade squamous intraepithelial lesion (LSIL), high-grade intraepithelial lesion (HSIL), and carcinoma were found in ten (2.6%), 11 (2.8%), 11 (2.8%), and three (0.8%) specimens, respectively. Follow-up of the 21 atypical cells/LSIL smears among seven patients revealed five NED with normal/benign smears, one NED with HSIL and one OR with HSIL. Follow-up of the 11 HSIL smears among four patients revealed two ICR, one OR and one NED with HSIL. Follow-up of the three carcinoma smears revealed three ICR (one followed by HSIL in a repeat Pap smear before ICR). The sensitivity for the detection of ICR by carcinoma smears was 50%, with a specificity and positive predictive value (PPV) of 100%.

CONCLUSION

Few (approximately 3%) of the routine follow-up Pap smears after CC patients receiving curative RT were HSIL/carcinoma, but most (4/6) of these patients turned out to be ICR.

Cholangiocarcinoma presenting as pseudoachalasia and gastroparesis

Cholangiocarcinoma most commonly presents as painless progressive jaundice. We report a case occurring in a 56-year-old Chinese woman with an unusual presentation of progressive dysphagia and vomiting. Oesophageal manometric and barium studies were indicative of achalasia, and computed tomography confirmed the presence of cholangiocarcinoma extending to the gastroesophageal junction and proximal lesser curve of the stomach. In this case, a constricting tumour at the gastroesophageal junction with probable invasion of the vagus nerves led to features of achalasia and gastroparesis.

An initial assessment of the feasibility and effectiveness of implementing diabetes shared care system in Taiwan--some experiences from I-Lan County

Diabetes is the fifth leading cause of death in Taiwan and the burden of suffering is still increasing. Building a comprehensive and efficient health care system is crucial to improve the outcome of the diabetics. We implemented the first diabetes shared care system of Taiwan in I-Lan County since August 1996 under the support of Department of Health, the Executive Yuan. This county-wide system was named 'Lan-Yang Diabetes Shared Care System' by the regional steering committee. Regional guidelines for diabetes management were developed after extensive discussion. A multidisciplinary diabetes care team was organized through a training and certification process. Registered patients held diabetes passports to keep clinical record. Physicians of the system use shared referral protocols and sheets. By the end of June 1999, 99 medical professionals had completed their training for diabetes shared care and been certified. The shared care system awarded 26 clinics to hang the lamp signs with the system logo to make them distinguishable. Such clinics have now been available throughout 12 townships in I-Lan County. The number of registered patients carrying diabetes passport increased to 3484 and there was a community-based patient group in every township of I-Lan County. The amount of continuing diabetes clinical training delivered by the specialists to the primary care physicians and non-physician professionals increased to 1681 person-hours per year. The proportion of registered patients undertaking fundus examination within 1 year increased to 30.9%, checking urine micro-albumin to 28.0% and checking HbA(1c) 72.8%, respectively. Mean HbA(1c) value decreased from 8.7% in the first year to 7.9% in the third year. Our study showed that under the co-ordination by regional health bureau with integration of different levels of medical facilities, governmental sectors and non-governmental community resources, the diabetes shared care model is feasible in Taiwan. Through its implementation, quality of regional diabetes care has achieved preliminary improvement.

Direct costs-of-illness of patients with diabetes mellitus in Taiwan

The purpose of the present study was to examine the characteristics of healthcare costs for diabetic patients in Taiwan. The study analyzed claim data from the Bureau of National Health Insurance for the period from July 1997 to June 1998. There were 536159 documented diabetic patients who were treated within the universal healthcare system in Taiwan during this study period. The annual number of visits of these diabetic patients was 6.2% of the total outpatient visits of all patients due to all causes during the one-year study period. Diabetes-related problems were the causes of 25.2% of outpatient visits among diabetic patients, while 74.8% of visits were for causes unrelated to diabetes. The distribution of treatment for the diabetic patients was by oral hypoglycemic agents 88.3%, insulin only 6.9%, and a combination of insulin and oral agents 4.8%. Diabetic patients accounted for 4,724,711 hospital inpatient days during the study period, which was 22.1% of the total inpatient days in Taiwan. Of the inpatient admissions, 13.9% were for diabetes as the principal cause, 23.4% were for diabetes-related disease, and 62.7% were for causes unrelated to diabetes. The direct costs of healthcare for the documented diabetic patients was 11.5% of the total costs of healthcare in Taiwan, and was 4.3 times higher than the average costs of care for non-diabetic individuals.

Incidence of gastroesophageal malignancy in patients with dyspepsia in Hong Kong: implications for screening strategies

BACKGROUND

A "test-and-treat" strategy for H pylori infection has been recommended in Europe and North America as safe and cost-effective for management of patients with dyspepsia. The primary aim of this study was to determine the frequency of gastroesophageal cancer in 2 groups of patients with dyspepsia: those 45 years of age or younger without "alarm" symptoms (low-risk group) and patients over 45 years of age or any patient with "alarm" symptoms (high-risk group). A secondary aim was to determine the frequency of gastric cancer among patients in the low-risk group with or without a positive serology for H pylori.

METHODS

Patients with persistent dyspepsia were recruited from 4 regional hospitals in Hong Kong. Those in the low-risk group were evaluated for H pylori by using a whole blood serology test; they underwent endoscopy within 1 week. Those in the high-risk group and those taking nonsteroidal anti-inflammatory drugs (NSAIDs) underwent endoscopy promptly. Alarm symptoms were as follows: weight loss (10 or more pounds over 8 weeks), recurrent vomiting, dysphagia, bleeding, or anemia.

RESULTS

Of 2627 patients enrolled, 1017 were in the low-risk group and 1610 in the high-risk group. Twenty-three patients (0.9%) had gastroesophageal cancers (20 gastric, 3 esophageal). Four patients with cancer (17.4%) were in the low-risk group (3 gastric, 1 esophageal); all except the patient with esophageal cancer had a positive serology test. In the high-risk group, 19 patients had cancer (17 gastric, 2 esophageal).

CONCLUSION

Gastric cancer is relatively frequent among young patients with dyspepsia who have no alarm features in Hong Kong. This finding raises concerns as to the safety of the "test-and-treat" strategy for the management of patients with dyspepsia in Asia.

Preventing recurrent upper gastrointestinal bleeding in patients with Helicobacter pylori infection who are taking low-dose aspirin or naproxen

BACKGROUND

Many patients who have had upper gastrointestinal bleeding continue to take low-dose aspirin for cardiovascular prophylaxis or other non-steroidal antiinflammatory drugs (NSAIDs) for musculoskeletal pain. It is uncertain whether infection with Helicobacter pylori is a risk factor for bleeding in such patients.

METHODS

We studied patients with a history of upper gastrointestinal bleeding who were infected with H. pylori and who were taking low-dose aspirin or other NSAIDs. We evaluated whether eradication of the infection or omeprazole treatment was more effective in preventing recurrent bleeding. We recruited patients who presented with upper gastrointestinal bleeding that was confirmed by endoscopy. Their ulcers were healed by daily treatment with 20 mg of omeprazole for eight weeks or longer. Then, those who had been taking aspirin were given 80 mg of aspirin daily, and those who had been taking other NSAIDs were given 500 mg of naproxen twice daily for six months. The patients in each group were then randomly assigned separately to receive 20 mg of omeprazole daily for six months or one week of eradication therapy, consisting of 120 mg of bismuth subcitrate, 500 mg of tetracycline, and 400 mg of metronidazole, all given four times daily, followed by placebo for six months.

RESULTS

We enrolled 400 patients (250 of whom were taking aspirin and 150 of whom were taking other NSAIDs). Among those taking aspirin, the probability of recurrent bleeding during the six-month period was 1.9 percent for patients who received eradication therapy and 0.9 percent for patients who received omeprazole (absolute difference, 1.0 percent; 95 percent confidence interval for the difference, -1.9 to 3.9 percent). Among users of other NSAIDs, the probability of recurrent bleeding was 18.8 percent for patients receiving eradication therapy and 4.4 percent for those treated with omeprazole (absolute difference, 14.4 percent; 95 percent confidence interval for the difference, 4.4 to 24.4 percent; P=0.005).

CONCLUSIONS

Among patients with H. pylori infection and a history of upper gastrointestinal bleeding who are taking low-dose aspirin, the eradication of H. pylori is equivalent to treatment with omeprazole in preventing recurrent bleeding. Omeprazole is superior to the eradication of H. pylori in preventing recurrent bleeding in patients who are taking other NSAIDs.

Long-term arsenic exposure and incidence of non-insulin-dependent diabetes mellitus: a cohort study in arseniasis-hyperendemic villages in Taiwan

Diabetes prevalence in arseniasis-hyperendemic villages in Taiwan has been reported to be significantly higher than in the general population. The aim of this cohort study was to further evaluate the association between ingested inorganic arsenic and the incidence of non-insulin-dependent diabetes mellitus in these villages. A total of 446 nondiabetic residents in these villages were followed biannually by oral glucose tolerance test. Diabetes is defined as a fasting plasma glucose level > or = 7.8 mmol/L and/or a 2-hr post-load glucose level > or = 11.1 mmol/L. During the follow-up period of 1499.5 person-years, 41 cases developed diabetes, showing an overall incidence of 27.4/1,000 person-years. The incidence of diabetes correlated with age, body mass index, and cumulative arsenic exposure. The multivariate-adjusted relative risks were 1.6, 2.3, and 2.1 for age > or = 55 versus < 55 years, a body mass index ¿Greater/Equal to] 25 versus < 25 kg/m(2), and a cumulative arsenic exposure > or = 17 versus < 17 mg/L-years, respectively. The incidence density ratios (95% confidence intervals) between the hyperendemic villages and the two nonendemic control townships were 3.6 (3.5-3.6), 2.3 (1.1-4.9), 4.3 (2.4-7.7), and 5.5 (2.2-13.5), respectively, for the age groups of 35-44, 45-54, 55-64, and 65-74 years. The findings are consistent with our previous cross-sectional observation that ingested inorganic arsenic is diabetogenic in human beings.

Estimation of sojourn time in chronic disease screening without data on interval cases

Estimation of the sojourn time on the preclinical detectable period in disease screening or transition rates for the natural history of chronic disease usually rely on interval cases (diagnosed between screens). However, to ascertain such cases might be difficult in developing countries due to incomplete registration systems and difficulties in follow-up. To overcome this problem, we propose three Markov models to estimate parameters without using interval cases. A three-state Markov model, a five-state Markov model related to regional lymph node spread, and a five-state Markov model pertaining to tumor size are applied to data on breast cancer screening in female relatives of breast cancer cases in Taiwan. Results based on a three-state Markov model give mean sojourn time (MST) 1.90 (95% CI: 1.18-4.86) years for this high-risk group. Validation of these models on the basis of data on breast cancer screening in the age groups 50-59 and 60-69 years from the Swedish Two-County Trial shows the estimates from a three-state Markov model that does not use interval cases are very close to those from previous Markov models taking interval cancers into account. For the five-state Markov model, a reparameterized procedure using auxiliary information on clinically detected cancers is performed to estimate relevant parameters. A good fit of internal and external validation demonstrates the feasibility of using these models to estimate parameters that have previously required interval cancers. This method can be applied to other screening data in which there are no data on interval cases.

Evaluation of a selective screening for colorectal carcinoma: the Taiwan Multicenter Cancer Screening (TAMCAS) project

BACKGROUND

Although the efficacy of mass screening for colorectal carcinoma (CRC) with a fecal occult blood test has been demonstrated in several randomized trials, a mass screening approach used in countries with intermediate or low incidence of CRC might be costly. Screening high risk people may be an alternative approach, to aid in the prevention of death from CRC. However, the efficacy of CRC screening for high risk people in such countries is uncertain.

METHODS

For this study, a multicenter design was devised to identify high risk groups without clinical symptoms related to CRC; these subjects were identified through the study of index cases of CRC in Taiwan. Colonoscopy, in combination with a fecal occult blood test or double-contrast barium enema, was used to screen high risk groups. A total of 8909 subjects were invited to attend screening. Of 8909, 81 with asymptomatic CRC were detected in one-shot screening. Markov models, in conjunction with a simulated approach, were proposed to estimate relevant parameters in relation to disease progression and to assess the effect of the interval between screenings on the efficacy of CRC screening for these high risk groups.

RESULTS

The estimated preclinical incidence rate was 0. 00396 (95% confidence interval [CI], 0.002944-0.004985), which was 21 times that reported from a cancer registry in 1994. The simultaneous estimations of mean sojourn time (the average duration between the preclinical screen-detectable phase and the clinical phase) and sensitivity were 2.8 years (95% CI, 2.15-4.30) and 95.0% (95% CI, 24.4-99.9%), respectively. Predictions of mortality reduction for people who received annual, biennial, and triennial screening regimes compared with controls were 26% (95% CI, 0-50%), 23% (95% CI, 0-48%), and 21% (95% CI, 0-47%), respectively.

CONCLUSIONS

The efficacy of selective colorectal carcinoma screening has been demonstrated in this study. A high preclinical CRC incidence rate also suggests that such a screening strategy might be cost-effective for countries with intermediate or low incidence of CRC. Methods proposed in this study can be used to evaluate the efficacy of CRC screening in similar screening trials.

Acute fish liver intoxication: report of three cases

The livers of some larger fish such as shark, tuna and seabass have been reported to be responsible for a peculiar poisoning causing headaches and desquamation. This type of poisoning can also be induced by ingestion of the livers of the sea whale, the polar bear and the seal. Since these animals contain an extremely large quantity of vitamin A in their livers and the symptoms of poisoning in the patients resembled those of patients with acute hypervitaminosis A, the poisoning was believed to have been caused by excessive vitamin A intake. We observed an episode of acute fish liver intoxication in which 3 man experienced dizziness, headache, blurred vision, nausea, vomiting, fever, and desquamation after ingesting the liver of the grouper fish Cephalopholis boenak (C. boenak). One of the patients had full-blown symptoms and presented with a high fever, headache, dizziness, generalized aching pain, and superficial vesicles and bullae of the skin. The treatment was mainly supportive. In the follow-up period, he subsequently developed hair loss and diffuse peeling of the skin on his palms and soles. Acute fish liver intoxication is rare, especially in subtropical regions. Symptomatologically, the clinical pictures of these patients were comparable to acute hypervitaminosis A or retinoid intoxication. The average vitamin A content in the grouper (C. boenak) is high enough to cause acute vitamin A intoxication. Moreover, ethanol may play a potentiating role in this type of event.

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.

Efficacy of breast-cancer screening for female relatives of breast-cancer-index cases: Taiwan multicentre cancer screening (TAMCAS)

Although the efficacy of mass screening for breast cancer has been established in Western countries, this strategy may be too costly for other countries with low incidence rates of breast cancer. We propose an alternative approach to screen female relatives of breast-cancer-index cases from hospitals, as part of the Taiwan multicentre cancer screening (TAMCAS) project. In order to assess the efficacy of this programme, and to estimate how often this high-risk group should be screened, we firstly elucidated the disease natural history from the pre-clinical screen-detectable phase (PCDP) by estimating the relevant parameters based on Markov chain models. We further predicted the proportion of interval cancers, advanced breast tumours and deaths from breast cancers by different screening frequencies. Results showed that the estimate of mean sojourn time (MST) for this high-risk group (1.9 years; 95% CI.1.18-4.86) is shorter than that for females from the general population. Analysis of a surrogate endpoint based on regional lymph-node spread and tumour size shows that annual screening for this high-risk group is likely to confer a significant 33% reduction in breast-cancer mortality compared with a non-significant 25 and 20% reduction for 2 yearly and 3-yearly screening regimes respectively. The above results suggest that a 1-year interval might be appropriate for this high-risk group. A simple cost-effectiveness analysis indicates a cost per year of life saved for mass screening ($72,480) 15 times that for the high-risk group ($4,851 ).

Universal hepatitis B vaccination in Taiwan and the incidence of hepatocellular carcinoma in children. Taiwan Childhood Hepatoma Study Group

BACKGROUND

A nationwide hepatitis B vaccination program was implemented in Taiwan in July 1984. To assess the effect of the program on the development of hepatocellular carcinoma, we studied the incidence of this cancer in children in Taiwan from 1981 to 1994.

METHODS

We collected data on liver cancer in children from Taiwan's National Cancer Registry, which receives reports from each of the country's 142 hospitals with more than 50 beds. Data on childhood liver cancer were also obtained from Taiwan's 17 major medical centers. To prevent the inclusion of cases of hepatoblastoma, the primary analysis was confined to liver cancers in children six years of age or older. Data were also obtained on mortality from liver cancer among children.

RESULTS

The average annual incidence of hepatocellular carcinoma in children 6 to 14 years of age declined from 0.70 per 100,000 children between 1981 and 1986 to 0.57 between 1986 and 1990, and to 0.36 between 1990 and 1994 (P<0.01). The corresponding rates of mortality from hepatocellular carcinoma also decreased. The incidence of hepatocellular carcinoma in children 6 to 9 years of age declined from 0.52 for those born between 1974 and 1984 to 0.13 for those born between 1984 and 1986 (P<0.001).

CONCLUSIONS

Since the institution of Taiwan's program of universal hepatitis B vaccination, the incidence of hepatocellular carcinoma in children has declined.

Establishment of a work-related diseases surveillance system in Taiwan, Republic of China

BACKGROUND

The occurrence of occupational illness and injury has been seriously underestimated in Taiwan, which subsequently contributes to difficulties in performing effective control of occupational hazards and implementing intervention programs for protecting workers.

METHODS

Based on the successful experience of the nationwide blood lead level surveillance program, the Department of Health, the Executive Yuan, Taiwan, Republic of China, has established a work-related diseases surveillance system. This government-administered system requests practicing physicians to report the suspected cases suffering from six categories of work-related disorders.

RESULTS

An occupational illness and injury surveillance program in Taiwan has been in operation since June of 1995.

CONCLUSION

Background information of work-related diseases obtained from this surveillance system will be useful for providing better management of available resources for occupational medicine, for preventing hazards, and for enforcing occupational diseases prevention programs. Our experience in establishing this surveillance system will be used in other countries and settings.

Prescribing patterns in primary health care in Taiwan

To identify the prescribing patterns in public group practice centers (GPCs), 84,453 prescription sheets written by primary care physicians in 168 GPCs during the period from December 7-12, 1992, were collected and analyzed. The average number of drugs per script was 4.3 and the ratio of drug to total medical expense was 44%. The 5 most common diagnoses were, in a descending order, upper respiratory tract infection, skeletomuscular and joint disease, hypertension, functional gastrointestinal disorder (including peptic ulcer) and diabetes mellitus. The top 5 most commonly dispensed drug categories were antacids and anti-ulcer drugs, anti-cough and anti-cold preparations, vitamins, simple analgesics and non-steroidal anti-inflammatory drugs, accounting for 48.8% of total prescriptions. In view of the frequency of relevant diagnoses, the overuse of antacids, vitamins, intravenous nutrient and electrolyte solutions, anti-cold preparations and antibiotics was apparent, as was that of drugs of questionable pharmacological value. These data indicate that polypharmacy is a widespread phenomenon and confirms our long-term concern over irrational drug use in GPCs in Taiwan. Both administrative and educational intervention should be implemented to improve prescribing quality at the primary health care level.

Increased prevalence of hypertension and long-term arsenic exposure

To examine the association between long-term exposure to inorganic arsenic and the prevalence of hypertension, we studied a total of 382 men and 516 women residing in villages where arseniasis was hyperendemic. Hypertension was defined as a systolic blood pressure of 160 mm Hg or greater, a diastolic blood pressure of 95 mm Hg or greater, or a history of hypertension treated regularly with antihypertensive drugs. The long-term arsenic exposure was calculated from the history of artesian well water consumption obtained through standardized interviews based on a structured questionnaire and the measured arsenic concentration in well water. Residents in villages where long-term arseniasis was hyperendemic had a 1.5-fold increase in age- and sex-adjusted prevalence of hypertension compared with residents in nonendemic areas. Duration of artesian well water consumption, average arsenic concentration in drinking water, and cumulative arsenic exposure were all significantly associated with hypertension prevalence. The higher the cumulative arsenic exposure, the higher the prevalence of hypertension. This dose-response relation remained significant after adjustment for age, sex, diabetes mellitus, proteinuria, body mass index, and serum triglyceride level. The results suggest that long-term arsenic exposure may induce hypertension in humans.

Ingested inorganic arsenic and prevalence of diabetes mellitus

To examine the association between ingested inorganic arsenic and prevalence of diabetes mellitus, in 1988, the authors studied 891 adults residing in villages in southern Taiwan where arseniasis is hyperendemic. The status of diabetes mellitus was determined by an oral glucose tolerance test and a history of diabetes regularly treated with sulfonylurea or insulin. The cumulative arsenic exposure in parts per million-years was calculated from the detailed history of residential addresses and duration of drinking artesian well water obtained through standardized interviews based on a structured questionnaire and the arsenic concentration in well water. The body mass index was derived from body height and weight measured according to a standard protocol, while the physical activity at work was also obtained by questionnaire interviews. Residents in villages where the chronic arseniasis was hyperendemic had a twofold increase in age- and sex-adjusted prevalence of diabetes mellitus compared with residents in Taipei City and the Taiwan area. There was a dose-response relation between cumulative arsenic exposure and prevalence of diabetes mellitus. The relation remained significant after adjustment for age, sex, body mass index, and activity level at work by a multiple logistic regression analysis giving a multivariate-adjusted odds ratio of 6.61 and 10.05, respectively, for those who had a cumulative arsenic exposure of 0.1-15.0 and greater than 15.0 ppm-year compared with those who were unexposed. These results suggest the chronic arsenic exposure may induce diabetes mellitus in humans.

Increased sister chromatid exchange frequency in peripheral lymphocytes of nasopharyngeal carcinoma and cervical cancer patients

The specific aim of this study was to compare the frequency of sister chromatid exchange (SCE) in peripheral lymphocytes using it as a biomarker of integral exposures to carcinogens in 14 untreated newly-diagnosed nasopharyngeal carcinoma (NPC) patients, 16 untreated newly-diagnosed cervical cancer patients, and 30 healthy controls matched with patients on age, sex, cigarette smoking and alcohol drinking. Peripheral lymphocytes were cultured in RPMI 1640 medium containing 20% fetal calf serum and 6 microM phytohemagglutinin. After culture for 24 hours, 20 microM 5-bromo-2-deoxyuridine was added into the medium. Colcemid solution was further added after 70 hours. Harvested cells were stained with Hoesch 33258, illuminated, and restained with Giemsa. The SCE frequency was scored by two readers independently and blindly. The results showed a significantly increased SCE frequency in lymphocytes for NPC patients (mean +/- standard error = 14.7 +/- 1.7 SCEs/cell) compared with their matched controls (10.1 +/- 0.7 SCEs/cell) and for cervical cancer patients (12.0 +/- 0.9 SCEs/cell) compared with their matched controls (9.2 +/- 0.7 SCEs/cell). These results suggest that NPC and cervical cancer patients have a higher integral exposures to both viral and chemical carcinogens than matched controls.

[Serotype distribution of Pseudomonas aeruginosa. Comparative studies of nosocomial and community strains]

A total of 202 strains of Pseudomonas aeruginosa were collected from December 1980 to September 1982 at National Taiwan University Hospital. Of the 202 strains, 102 were nosocomial strains and the other 100 were community strains. The distribution of O antigen group were as follow: E, 34.2%; B, 17.3%; G, 10.9%; F, 9.9%, I, 7.9%; L, 7.4%; others, 12.4%. The antisera used were produced by Toshiba Kagaku Kogyo Co., Japan. The relationship between antibiotic susceptibility pattern and O antigen group were that group-I was the most susceptible group and group-L was the most resistant group. With the O antigen grouping and antibiotic susceptibility pattern, we tried to differentiate the nosocomial strains from the community strains. No obvious difference could be drawn.

Hepatitis A virus infection in Taiwan. A hospital-based study

One hundred and thirty-four healthy subjects and 220 patients with liver diseases were studied for antibody to hepatitis A virus (anti-HAV) with radio-immunoassay. The frequency of anti-HAV related closely to the age of healthy subjects; the rate of positivity increased with age, being 5.9% in those under four years, 13.3% in the late first decade and over 90% after the third decade. Taking meals at stalls with poor sanitary standards is suspected to cause the prevailing infection in teenagers, although a cohort effect due to environmental and socio-economic improvement can not be excluded. Anti-HAV was present in most patients with frequencies comparable to healthy subjects of the same age. It is concluded that in Taiwan the prevalent chronic liver diseases and hepatocarcinoma are unrelated to HAV infection and the patients are infected to an extent similar to healthy people of the same age.