P39 Cross-sectional analysis of 6-minute walk distance and diastolic function in a Hong Kong cohort of community-living older adults

Funding Acknowledgements

CUHK Direct Grant, CUHK Lui Che Woo Institute of Innovative Medicine, Food and Health Bureau of HKSAR (EF); Hong Kong Jockey Club Charities Trust (JW)

Background/Introduction

6-min walk distance (6MWD) can indicate frailty extent, cardiac dysfunction, and heart failure (HF) trajectory. Association of 6MWD with diastolic dysfunction (DD) or cardiac biomarker in community-living elderly without a history of HF remains underexplored.

Purpose

This study aims to determine the association between 6MWD, serum N-terminal prohormone of B-type natriuretic peptide (NT-proBNP), and DD in a community-living elderly population without known HF.

Methods

Between Nov 2017 and Aug 2018, 302 Hong Kong Chinese aged ≥60 y and without known HF were recruited into the Undiagnosed heart Failure in Older individuals (UFO) study consisting of robust, pre-frail and frail older adults stratified by FRAIL scale in a ratio of 1:1:1. 6MWD was divided into tertiles. Transthoracic echocardiography and serum NT-proBNP were used to assess cardiac dysfunction. Diastolic function was classified according to international guidelines and NT-proBNP >300 pg/ml was considered elevated.

Results

The ages of participants in the bottom, middle and top tertiles were 80.3 ± 7.4, 73.9 ± 6.3 and 70.0 ± 5.7 years (P < 0.01), respectively, corresponding to a female preponderance of 85.0%, 75.2%, 46.5% (P < 0.01). The highest prevalence rates of hypertension (HT, 76.0% vs 68.3% vs 51.5%, P < 0.01), diabetes mellitus (DM, 41.0% vs 30.7% vs 12.9%, P < 0.01), and ischaemic heart disease (IHD, 14.0% vs 4.0% vs 2.0%, P < 0.01) were observed in the bottom tertile of 6MWD. However, the prevalence of atrial fibrillation (AF) was distributed equally across tertiles (2.0% vs 2.0% vs 2.0%). Frail (63.0% vs 25.7% vs 3.0%, P < 0.01) and pre-frail (36.5% vs 44.6% vs 24.8%, P < 0.01) individuals were most frequently seen in the bottom and middle tertiles of 6MWD.

Using multiple linear regression analysis, S’ velocity, E:E’ ratio and E’ velocity were associated with 6MWD independent of age and sex. Associations between 6MWD and S’, left atrial volume index, E’ and E:E’ remained statistically significant even after adjusting for HT, DM, IHD, AF, stroke, chronic pulmonary disease and arthritis. No correlation was observed between 6MWD and left ventricular ejection fraction. 

Compared with the top tertile of 6MWD, the bottom tertile was associated with increased risks for grade II–IV DD (odds ratio (OR) 3.47, 95% confidence interval (CI) 1.52–7.96, P < 0.01) and NT-proBNP >300pg/ml (OR 10.20, CI 3.74–27.85, P < 0.01, respectively, after adjusting for co-morbidities. The association between reduced 6MWD and elevated NT-proBNP, but not between 6MWD and DD, remained significant (OR 6.00, CI 2.06–17.46) after adjusting for age and sex. The middle tertile was not significantly associated with an increased risk for grade II–IV DD or elevated NT-proBNP.

Conclusion(s)

In this cohort of community-living Hong Kong Chinese elderly recruited equally by frailty status, performance of 6MWD in the bottom and top tertiles was inversely associated with NT-proBNP levels but not with DD.

A model-free test for detecting disease association signals with multiple genetic variants and covariates

Discoveries and analyses of genetic variants at a gene or exome based on high-throughput sequencing technology are increasingly feasible. Although many well-known association tests have already been proposed in literature for testing whether a group of variants in a target region is associated with a disease of interest, however, the analytic challenges still remain profound. The power performance of these tests generally depends on the sample size, numbers of causal and neutral variants, variant frequency, effect size, and direction. Some of these factors are not easily controllable in practical applications. Further complications arise from missing genotype, population stratification or misspecification of the working model. Previous studies showed that many model-based tests might create false positive results or decrease power when there was population stratification effect or missing genotype and simple imputation was used. Here, we demonstrate by simulations that type I errors of the well-known model-based tests are often inflated as well, even the working model deviates slightly from the true model. We propose a model-free test and show this test to be almost uniformly most powerful among the competing tests under very general simulation conditions with covariates. This test does not require genotype data to be complete and hence difficult imputation can be avoided. We also discuss how to adjust for the effect of population stratification based on principal components, and use a Shanghai Breast Cancer Study to demonstrate application of the new test.

Detecting disease association signals with multiple genetic variants and covariates

Due to the improvements in the efficiency of resequencing technologies, discoveries and analyses of rare variants in sequencing-based association studies at the gene level, or even exome-wide are becoming increasingly feasible. Powerful association tests have been suggested in literature for testing whether a group of variants in a gene region is associated with a particular disease of interest. Their performance depends on the correct assumption of regression model and conditions such as the size of the case and control sample, numbers of causal and noncausal variants (rare or common), variant frequency, effect size and directionality, rate of missing genotype, etc. Most of these model-based tests require genotype data to be complete at each variant. Our previous results showed that in the case of no covariate, the power of these tests might be greatly influenced, when there were missing genotypes and only simple imputation was used. In this paper, we demonstrate by simulations that in the presence of covariates, the type I errors of these approaches might be inflated, even when genotype missing rate was very small. We present an association test based on testing zero proportion of causal variants in the gene region, and show this test to be almost uniformly most powerful among the competing tests under very general simulation conditions. This test does not require genotype to be complete and hence is robust against missing genotype. We discuss how to adjust for population stratification based on principal components and show the power loss of this approach was small when the population stratification effect was moderate. We use a Shanghai Breast Cancer Study to demonstrate application of the tests and show the proposed test is more powerful in detecting variants related to breast cancer, and robust against the inclusion of noncausal variants.

A powerful association test of multiple genetic variants using a random-effects model

There is an emerging interest in sequencing-based association studies of multiple rare variants. Most association tests suggested in the literature involve collapsing rare variants with or without weighting. Recently, a variance-component score test [sequence kernel association test (SKAT)] was proposed to address the limitations of collapsing method. Although SKAT was shown to outperform most of the alternative tests, its applications and power might be restricted and influenced by missing genotypes. In this paper, we suggest a new method based on testing whether the fraction of causal variants in a region is zero. The new association test, T REM , is derived from a random-effects model and allows for missing genotypes, and the choice of weighting function is not required when common and rare variants are analyzed simultaneously. We performed simulations to study the type I error rates and power of four competing tests under various conditions on the sample size, genotype missing rate, variant frequency, effect directionality, and the number of non-causal rare variant and/or causal common variant. The simulation results showed that T REM was a valid test and less sensitive to the inclusion of non-causal rare variants and/or low effect common variants or to the presence of missing genotypes. When the effects were more consistent in the same direction, T REM also had better power performance. Finally, an application to the Shanghai Breast Cancer Study showed that rare causal variants at the FGFR2 gene were detected by T REM and SKAT, but T REM produced more consistent results for different sets of rare and common variants.

Inflammatory state of type II diabetic patients with chronic ulcers in response to herbal treatment

BACKGROUND

Type II diabetic patients easily develop ulcers over their feet which heal with great difficulties and not infrequently, end up in amputations. In the quest for innovative means to avoid amputation, herbal medicine has been used in China to heal ulcers.

METHOD

A randomized placebo controlled clinical trial involving 80 patients was conducted to test whether a herbal formula taken orally could help to preserve the ulcerated leg. Other parameters measured included granulation maturation time, skin temperature and circulation, and tumor necrosis factor alpha (TNF-α).

RESULTS

showed a 85% limb rescue with the herbal treatment group showing superiority over placebo group. TNF-α decline was observed with gradual ulcer healing and the herbal supplement group showed a more impressive decline (p=0.037).

Assessing the joint effect of population stratification and sample selection in studies of gene-gene (environment) interactions

Background

It is well known that the presence of population stratification (PS) may cause the usual test in case-control studies to produce spurious gene-disease associations. However, the impact of the PS and sample selection (SS) is less known. In this paper, we provide a systematic study of the joint effect of PS and SS under a more general risk model containing genetic and environmental factors. We provide simulation results to show the magnitude of the bias and its impact on type I error rate of the usual chi-square test under a wide range of PS level and selection bias.

Results

The biases to the estimation of main and interaction effect are quantified and then their bounds derived. The estimated bounds can be used to compute conservative p-values for the association test. If the conservative p-value is smaller than the significance level, we can safely claim that the association test is significant regardless of the presence of PS or not, or if there is any selection bias. We also identify conditions for the null bias. The bias depends on the allele frequencies, exposure rates, gene-environment odds ratios and disease risks across subpopulations and the sampling of the cases and controls.

Conclusion

Our results show that the bias cannot be ignored even the case and control data were matched in ethnicity. A real example is given to illustrate application of the conservative p-value. These results are useful to the genetic association studies of main and interaction effects.

An easy-to-implement approach for analyzing case-control and case-only studies assuming gene-environment independence and Hardy-Weinberg equilibrium

The case-control study is a simple and an useful method to characterize the effect of a gene, the effect of an exposure, as well as the interaction between the two. The control-free case-only study is yet an even simpler design, if interest is centered on gene-environment interaction only. It requires the sometimes plausible assumption that the gene under study is independent of exposures among the non-diseased in the study populations. The Hardy-Weinberg equilibrium is also sometimes reasonable to assume. This paper presents an easy-to-implement approach for analyzing case-control and case-only studies under the above dual assumptions. The proposed approach, the 'conditional logistic regression with counterfactuals', offers the flexibility for complex modeling yet remains well within the reach to the practicing epidemiologists. When the dual assumptions are met, the conditional logistic regression with counterfactuals is unbiased and has the correct type I error rates. It also results in smaller variances and achieves higher powers as compared with using the conventional analysis (unconditional logistic regression).

Classical reflux symptoms, hiatus hernia and overweight independently predict pharyngeal acid exposure in patients with suspected reflux laryngitis

BACKGROUND

Gastro-oesophageal reflux disease (GERD) has been associated with reflux laryngitis.

AIMS

To investigate the risk factors and the predictors of pharyngeal acid reflux (PAR) in Taiwanese patients with suspected reflux laryngitis.

METHODS

With referral from ENT physicians, 104 patients with symptoms and signs suggestive of reflux laryngitis completed a validated symptom questionnaire, an upper endoscopy exam and ambulatory 24-h pH tests with three sensors located at the hypopharynx, proximal and distal oesophagus. Patients with one or more episodes of PAR were considered abnormal.

RESULTS

Pharyngeal acid reflux was identified in 17% (18/104) of patients. In multivariate logistic regression analysis, PAR was independently associated with classical reflux symptoms [adjusted odds ratio (aOR) = 3.5, 95% confidence interval (CI): 1.0-12.8], hiatus hernia (aOR = 6.7, 95% CI: 1.5-30.2) and overweight (aOR = 3.4, 95% CI: 1.0-11.0). In predicting PAR, classical reflux symptoms had a sensitivity of 78% and hiatus hernia had a specificity of 95%. With all three factors, the positive predictive value for PAR was 80%. Classical reflux symptoms included heartburn, chest pain, dyspepsia and acid regurgitation.

CONCLUSIONS

Classical reflux symptoms, hiatus hernia and overweight are independent risk factors that may predict pharyngeal acid reflux in patients with suspected reflux laryngitis.

A robust TDT-type association test under informative parental missingness

Many family-based association tests rely on the random transmission of alleles from parents to offspring. Among them, the transmission/disequilibrium test (TDT) may be considered to be the most popular statistical test. The TDT statistic and its variations were proposed to evaluate nonrandom transmission of alleles from parents to the diseased children. However, in family studies, parental genotypes may be missing due to parental death, loss, divorce, or other reasons. Under some missingness conditions, nonrandom transmission of alleles may still occur even when the gene and disease are not associated. As a consequence, the usual TDT-type tests would produce excessive false positive conclusions in association studies. In this paper, we propose a novel TDT-type association test which is not only simple in computation but also robust to the joint effect of population stratification and informative parental missingness. Our test is model-free and allows for different mechanisms of parental missingness across subpopulations. We use a simulation study to compare the performance of the new test with TDT and point out the advantage of the new method.

A powerful two-stage association test using case-control and case-parents genotype data

OBJECTIVE

The performance of association tests based on case-control or case-parents substudy alone can be improved by jointly using genetic data from two substudies. However, genetic data from different sources may not be combinable due to population stratification. We propose a two-stage association test based on using combinability tests in stage 1 and association tests in stage 2.

METHODS

The combinability tests are designed for testing that genotype data from different sources have same genotype frequencies and relative risks. The association tests are well known tests in the literature. We propose a method to adjust the significance levels at two stages so that the overall type I error rate of the two-stage test can be controlled at the desired level.

RESULTS

The simulation results confirm that the two-stage test has empirical type I error rates approximately equal to the predetermined levels while making substantially fewer false negatives than the usual test based only on case-parents substudy.

CONCLUSION

It is advantageous to combinecase-control and case-parents data into a single analysis.The two-stage test has significant power improvement when the family-based test has weak or moderate power performance and is robust to the effect of population stratification.

Combining unrelated family studies to improve the power of genetic association test

Family-based studies provide powerful inferences regarding associations between genetic variants and risks, but have limitations. Since very often, the availability of the parental genotypes can pose a problem for using family-based design, especially when the disease of interest has a late age of onset. To improve the efficiency of the studies, a popular approach is to reconstruct the missing genotypes from the genotypes of their offspring and correct the biases resulting from the reconstruction. In this paper, the author shows that two or more unrelated family studies, for the same candidate marker but different diseases, can also be combined to construct a more efficient test for association analysis. The usual case-control study with parental genotypes is a special case of the data discussed here. The author used a simulation study to compare the performance of the new method with other well-known methods. The results showed that the new test has an advantage of having larger power when there is no effect of population stratification between two study samples. However, if there is effect of population stratification between the two samples, the new test still maintains the expected type I error rate and has comparable power performance. Since the unrelated family studies not for the disease of interest are often readily accessible with minimal cost, the proposed method has practical value. The new approach can also be easily modified to allow for missing parental data.

Simultaneously correcting for population stratification and for genotyping error in case-control association studies

In population-based case-control association studies, the regular chi (2) test is often used to investigate association between a candidate locus and disease. However, it is well known that this test may be biased in the presence of population stratification and/or genotyping error. Unlike some other biases, this bias will not go away with increasing sample size. On the contrary, the false-positive rate will be much larger when the sample size is increased. The usual family-based designs are robust against population stratification, but they are sensitive to genotype error. In this article, we propose a novel method of simultaneously correcting for the bias arising from population stratification and/or for the genotyping error in case-control studies. The appropriate corrections depend on sample odds ratios of the standard 2x3 tables of genotype by case and control from null loci. Therefore, the test is simple to apply. The corrected test is robust against misspecification of the genetic model. If the null hypothesis of no association is rejected, the corrections can be further used to estimate the effect of the genetic factor. We considered a simulation study to investigate the performance of the new method, using parameter values similar to those found in real-data examples. The results show that the corrected test approximately maintains the expected type I error rate under various simulation conditions. It also improves the power of the association test in the presence of population stratification and/or genotyping error. The discrepancy in power between the tests with correction and those without correction tends to be more extreme as the magnitude of the bias becomes larger. Therefore, the bias-correction method proposed in this article should be useful for the genetic analysis of complex traits.

Efficacy and tolerability of a Chinese herbal medicine concoction for treatment of atopic dermatitis: a randomized, double-blind, placebo-controlled study

BACKGROUND

There has been considerable interest in traditional Chinese herbal medicine (TCHM) as a treatment for atopic dermatitis (AD). A twice-daily concoction of an ancestral formula containing five herbs has been found to be beneficial in an open study.

OBJECTIVES

To assess the efficacy and tolerability of the concoction in children with AD.

METHODS

Following a 2-week run-in period, children with long-standing moderate-to-severe AD were randomized to receive a 12-week treatment with twice-daily dosing of three capsules of either TCHM or placebo. The SCORing of Atopic Dermatitis (SCORAD) score, Children's Dermatology Life Quality Index (CDLQI), allergic rhinitis score, and requirement for topical corticosteroid and oral antihistamine were assessed before and at weeks 4, 8, 12 and 16 after treatment. Adverse events, tolerability, haematological and biochemical parameters were monitored during the study.

RESULTS

Eighty-five children with AD were recruited. Over 12 weeks, the mean SCORAD score fell from 58.3 to 49.7 in the TCHM group (n = 42; P = 0.003) and from 56.9 to 46.9 in the placebo group (n = 43; P = 0.001). However, there was no significant difference in the scores at the corresponding time points between the two groups. The CDLQI in TCHM-treated patients was significantly improved compared with patients receiving placebo at the end of the 3-month treatment and 4 weeks after stopping therapy (P = 0.008 and 0.059, respectively). The total amount of topical corticosteroid used was also significantly reduced by one-third in the TCHM group (P = 0.024). No serious adverse effects were observed between the groups.

CONCLUSIONS

The TCHM concoction is efficacious in improving quality of life and reducing topical corticosteroid use in children with moderate-to-severe AD. The formulation was palatable and well tolerated.

A simple and robust TDT-type test against genotyping error with error rates varying across families

The transmission/disequilibrium test (TDT), a family based test of linkage and association, is a popular test for studies of complex inheritance, as it is nonparametric and robust against spurious conclusions induced by hidden genetic structure, such as stratification or admixture. However, the TDT may be biased by genotyping errors. Undetected genotyping errors may be contributing to an inflated type I error rate among reported TDT-derived associations. To adjust for bias, a popular approach is to assume a genotype error model for describing the pattern of errors and propose association tests using likelihood method. However, all model-based approaches tend to perform unsatisfactorily if the related genotyping error rates are not identical across all families. In this paper, we propose a TDT-type association test which is not only simple, robust against population stratification (and hence the assumption of Hardy-Weinberg equilibrium is not required), but also robust against genotyping error with error rates varying across families. Simulation studies confirm that the new test has very reasonable performance.

What happened in China during the 1918 influenza pandemic?

Influenza has been, and continues to be, a serious threat to human life. The 1918 influenza pandemic infected nearly one quarter of the world's population and resulted in the deaths of 100 million people. Most of the countries in the world were heavily impacted. What happened in China during this period? Compared with other countries, the severity of infection in China was relatively mild. Did traditional Chinese medicine (TCM) play any role, either in the prevention or treatment of the epidemics? This paper explores the situation in China at that particular time.

Analysis of Case-Only Studies Accounting for Genotyping Error

The case-only design provides one approach to assess possible interactions between genetic and environmental factors. It has been shown that if these factors are conditionally independent, then a case-only analysis is not only valid but also very efficient. However, a drawback of the case-only approach is that its conclusions may be biased by genotyping errors. In this paper, our main aim is to propose a method for analysis of case-only studies when these errors occur. We show that the bias can be adjusted through the use of internal validation data, which are obtained by genotyping some sampled individuals twice. Our analysis is based on a simple and yet highly efficient conditional likelihood approach. Simulation studies considered in this paper confirm that the new method has acceptable performance under genotyping errors.

A maximum likelihood method for studying gene-environment interactions under conditional independence of genotype and exposure

Given the biomedical interest in gene-environment interactions along with the difficulties inherent in gathering genetic data from controls, epidemiologists need methodologies that can increase precision of estimating interactions while minimizing the genotyping of controls. To achieve this purpose, many epidemiologists suggested that one can use case-only design. In this paper, we present a maximum likelihood method for making inference about gene-environment interactions using case-only data. The probability of disease development is described by a logistic risk model. Thus the interactions are model parameters measuring the departure of joint effects of exposure and genotype from multiplicative odds ratios. We extend the typical inference method derived under the assumption of independence between genotype and exposure to that under a more general assumption of conditional independence. Our maximum likelihood method can be applied to analyse both categorical and continuous environmental factors, and generalized to make inference about gene-gene-environment interactions. Moreover, the application of this method can be reduced to simply fitting a multinomial logistic model when we have case-only data. As a consequence, the maximum likelihood estimates of interactions and likelihood ratio tests for hypotheses concerning interactions can be easily computed. The methodology is illustrated through an example based on a study about the joint effects of XRCC1 polymorphisms and smoking on bladder cancer. We also give two simulation studies to show that the proposed method is reliable in finite sample situation.

Retrospective analysis of case-control studies when the population is in Hardy-Weinberg equilibrium

Association analysis of genetic polymorphisms has been mostly performed in a case-control setting in connection with the traditional logistic regression analysis. However, in a case-control study, subjects are recruited according to their disease status and their past exposures are determined. Thus the natural model for making inference is the retrospective model. In this paper, we discuss some retrospective models and give maximum likelihood estimators of exposure effects and estimators of asymptotic variances, when the frequency distribution of exposures in controls contains information about the parameters of interest. Two situations about the control population are considered in this paper: (a) the control population or its subpopulations are in Hardy-Weinberg equilibrium; and (b) genetic and environmental factors are independent in the control population. Using the concept of asymptotic relative efficiency, we shall show the precision advantages of such retrospective analysis over the traditional prospective analysis. Maximum likelihood estimates and variance estimates under retrospective models are simple in computation and thus can be applied in many practical applications. We present one real example to illustrate our methods.

Using herbal medicine as a means of prevention experience during the SARS crisis

At the peak of the SARS epidemic in Hong Kong, hospital workers were under high risks of contraction of the infection. Herbal preparations had been used historically in China to treat influenza-like diseases. During the SARS outbreak, herbal preparations had been used jointly with standard modern treatment in China. As a means to protect the at-risk hospital workers, an innovative herbal formula was created and consumed by 3160 of them in two weeks. During the two weeks, symptoms and adverse effects were close monitored; 37 of them had their serum checked for immunological responses. The results showed that none of the herb consumers contracted the infection, compared to 0.4% among the non-consumers. Adverse effects had been infrequent and mild. There were hardly any influenza-like symptoms and the quality of life improved. In the group who volunteered to have their immunological state checked, significant boosting effects were found. It was concluded that there might be a good indication for using suitable herbal preparations as a means of preventing influenza-like infection. The mode of preventive effect could be treatment of the infection at its very early stage instead of producing a period of higher immunological ability, as in the case of vaccination.

The use of an herbal formula by hospital care workers during the severe acute respiratory syndrome epidemic in Hong Kong to prevent severe acute respiratory syndrome transmission, relieve influenza-related symptoms, and improve quality of life: a prospective cohort study

OBJECTIVES

To investigate the efficacy of an herbal formula in the prevention of severe acute respiratory syndrome (SARS) transmission among health care workers. The secondary objectives are to investigate quality of life (QOL) and symptomology changes among supplement users, and to evaluate the safety of this formula.

DESIGN

Controlled clinical trial.

SETTINGS

Hong Kong during epidemic of SARS.

SUBJECTS

Two cohorts of health care workers from 11 hospitals in Hong Kong, 1 using an herbal supplement for a 2-week period (n = 1063) and a control cohort comprising all other health care workers who did not receive the supplement (n = 36,111) were compared prospectively.

INTERVENTIONS

Taking an herbal supplement for a 2-week period.

OUTCOME MEASURES

SARS attack rates and changes in quality of life and influenza-like symptoms were also examined at three timepoints among herbal supplement users.

RESULTS

None of the health care workers who used the supplement subsequently contracted SARS compared to 0.4% of the health care workers who did not use the supplement (p = 0.014). Improvements in influenza-like symptoms and quality of life measurements were also observed among herbal supplement users. Less than 2% reported minor adverse events.

CONCLUSION

The results of this pilot study suggest that there is a good potential of using Traditional Chinese Medicine (TCM) supplements to prevent the spread of SARS.

Bayesian models for population-based case-control studies when the population is in Hardy-Weinberg equilibrium

Association analysis of genetic polymorphisms has been mostly performed in a case-control setting with unrelated affected subjects compared with unrelated unaffected subjects. In this paper, we present a Bayesian method for analyzing such case-control data when the population is in Hardy-Weinberg equilibrium. Our Bayesian method depends on the informative prior which is the retrospective likelihood based on historical data, raised to a power a. By modeling the retrospective likelihood properly, different prior information about the studied population can be incorporated into the specification of the prior. The scalar a is a precision parameter quantifying the heterogeneity between current and historical data. A guide value for a is discussed in this paper. The informative prior and posterior distributions are proper under very general conditions. Therefore, our method can be applied in most case-control studies. Further, for assessing gene-environment interactions, our approach will naturally lead to a Bayesian model depending only on the case data, when genotype and environmental factors are independent in the population. Thus our approach can be applied to case-only studies. A real example is used to show the applications of our method.

Interactions between modern and Chinese medicinal drugs: a general review

While the use of health food and over-the-counter drugs for health promotion and adjuvant therapy is becoming increasingly popular, the concern about adverse effects is mounting. The possible adverse effects that may arise from drug interactions between these herbal preparations and standard modem therapy are equally worrying. Herbal toxicity and adverse effects are well documented in classical Chinese medicinal volumes. Interactions between herbal preparations and standard modem therapy are known. Extensive work needs to be done before useful guidelines can be established. However, based on available reports and clinical observations, some commonly used herbs and Chinese medicines have already demonstrated the need for special attention when used together with modern therapy. This paper analyzes the important material already available, and would serve as a preliminary checklist for patients who are taking herbal preparations, while at the same time receiving treatment from modern medicine.

Compounds from Kadsura ananosma

The 18-(13-->12 beta)-abeo-lanostene triterpenoid acid, ananosic acid A (1), and the dibenzocyclooctadiene lignan, ananosin A (2), were isolated from the stem bark of Kadsura ananosma. Their structures were elucidated by extensive spectral studies and the structure of 1 was confirmed by single crystal X-ray diffraction analysis.

Cytotoxic oxoisoaporphine alkaloids from Menispermum dauricum

Four new oxoisoaporphine alkaloids, daurioxoisoporphines A-D (1-4), were isolated from the rhizomes of Menispermum dauricum. The structures of these alkaloids were established by spectroscopic methods. The cytotoxic evaluation of 1 and 2 is reported against four cancer cell lines.

Tandem conjugate reduction-aldol cyclization using Stryker's reagent

[see reaction]. Conjugate reduction by Stryker's reagent to form copper enolates, followed by intramolecular aldol cyclization, successfully generated five- and six-membered carbocycles in one pot efficiently. This tandem reaction is generally diastereoselective and provides good yields of the beta-hydroxyketones without any dehydration at low temperatures.

A rhodium carbene cyclization-cycloaddition cascade strategy toward the pseudolaric acids

A rhodium carbene intramolecular cyclization-cycloaddition cascade was employed as the key reaction in the synthesis of the nucleus of the cytotoxic diterpenoids pseudolaric acids A and B.

Four mono-tetrahydrofuran ring acetogenins, montanacins B-E, from Annona montana

Four novel mono-tetrahydrofuran (THF) acetogenins, montanacins B-E (1-4), were isolated from the ethanolic extract of the leaves of Annona montana. The structures of 1-4 were established by spectroscopic methods and their absolute stereochemistries were determined by the advanced Mosher ester method. Montancins D (3) and E (4) bear a non-adjacent tetrahydropyran (THP) ring along with a THF ring and are the most unusual type of acetogenins discovered so far.

Diterpene glucosides from Pieris formosa

Five diterpene glucosides, pierisformosides B-F were isolated from Pieris formosa D. Don (Ericaceae). Their structures were elucidated on the basis of spectral analysis. including 1H-1H COSY, 13C-1H COSY, HMBC and NOESY experiments.

A new trinortriterpenoid from Cleome chrysantha

A new trinortriterpenoid, 1-epibrachyacarpone, was isolated from aerial parts of Cleome chrysantha. Its structure was elucidated as 1 by NMR investigations and X-ray crystallographic studies.

Yuehchukene, a bis-indole alkaloid, and cyclophosphamide are active in breast cancer in vitro

Yuehchukene (YCK) is a novel bis-indole alkaloid with weak estrogenic activity. Biochemical studies showed that YCK could attenuate estrogenic action. In this study, the response of MCF-7, an estrogen-receptor-positive breast cancer cell line, under different combinations of estradiol, cyclophosphamide and YCK, was tested. From the dose-response curve, we discovered that 10(-2) M cyclophosphamide, even in its so-called 'bio-inert' form, could inhibit MCF-7 cell growth. However, the cytotoxic effect of cyclophosphamide was lost by reducing its concentration to approximately 1 x 10(-3) M. On the other hand, a low concentration ( approximately 10(-8)-10(-9) M) of YCK was found to potentiate the cytotoxic effect of cyclophosphamide on the MCF-7 cell line. Such an effect was absent in the estrogen-receptor-negative cell line MDA-MB-231. These findings, together with the dual role of a mixed estrogen and anti-estrogen effect, suggested that YCK and cyclophosphamide can be a potential combination in chemo-hormonal therapy for breast cancer.

Grayanane diterpenoids from pieris formosa

Two new diterpenoids, pierisformoside A (1) and pierisformosin D (2), and two known diterpenoids, asebotoxins VIII (3) and V (4), were isolated from leaves of Pieris formosa. Their structures were elucidated on the basis of spectral analysis, including 1H-1H COSY, 13C-1H COSY, HMBC, and NOESY experiments.

Induction of estradiol-2-hydroxylase and ethoxyresorufin-O-deethylase by 3-substituted indole compounds

Estrogen can be hydroxylated at both 2- and 16alpha-positions. These two reactions are mutually exclusive. The 2-hydroxylated estrogen is relatively inactive compared with the 16alpha-derivative; hence, one approach in anti-estrogenic therapy is to look for drugs that can induce the 2-hydroxylation pathway. In the present study, using Balb/c and C57B/6 mice as the animal models, the induction effect of several isoprenyl compounds on estradiol-2-hydroxylase and ethoxyresorufin-O-deethylase activities was studied. The compounds examined included 2'- and 3'-methylbutadienyl-indoles and their respective acid condensation products, isopropyl indolocarbazole and yuehchukene; positional isomers of indole carbinols and carboxyaldehydes, as well as 3-methylcholanthrene, the prototype inducer of cytochrome P450 1A1. Our results demonstrated that while all of them were capable of inducing cytochrome P450 1A1-mediated ethoxyresorufin-O-deethylase activity, only the 3' isomers could induce estradiol-2-hydroxylase activity. The induction of these two activities did not show any direct correlation, suggesting that cytochrome P450 1A1 was not the same enzyme catalyzing both ethoxyresorufin-O-deethylation and estradiol-2-hydroxylation. Nevertheless, both inductions were mediated by the aryl hydrocarbon receptor. Among the compounds tested, yuehchukene showed competitive binding to estrogen receptor. This, together with the induction of estradiol-2-hydroxylase activity, may account for the anti-estrogenic effect of yuehchukene.

Lignans from Kadsura angustifolia

A new dibenzocyclooctadiene lignan named angustifolin D (1) together with four known lignans: kadsulignan L (2), kadsulignan N (3), schisantherin P (4) and meso-dihydroguaiaretic acid (5) were isolated from the stems of Kadsura angustifolia. Their structures and stereochemistries were elucidated by spectral studies. Compounds 2 and 5 showed moderate platelet-activating factor (PAF) antagonistic activities with IC50 values of 2.6 x 10(-5) and 4.1 x 10(-5) M, respectively.

Triterpenes and triterpenoid saponins from Mussaenda pubescens

Two novel triterpenoid saponins, named mussaendosides U and V, together with one known saponin and four known triterpenes were isolated from the aerial parts of Mussaenda pubescens (Rubiaceae). The structures were determined on the basis of chemical analysis ad spectral methods. All these compounds were identified for the first time from the genus Mussaenda.

Growth characteristics of normal and dystrophic myoblasts in primary myoblast cultures

This study employed immunocytochemistry and toluidine blue counterstaining to compare different procedures utilized in primary myoblast cultures, from which an optimal culture model for normal myoblasts could be derived. The growth characteristics of normal and dystrophic myoblasts were also investigated by means of this model. Results indicate that the requirements for an ideal myoblast culture should include a combined enzyme of 0.25% trypsin and 0.2% collagenase (type IV) (1:1), a preplating time of approximately 15-20 minutes, and a seeding density of 1 x 10(5) cells/ml. Furthermore, the mouse samples should be newborn mice. A better proliferative capacity of myoblasts was noted in an incubator with 10% CO2 coupled with Dulbecco's MEM plus 15% fetal calf serum. With regard to the growth characteristics of normal and dystrophic myoblasts, the doubling time of normal myoblasts was shorter than that of dystrophic myoblasts. In terms of the fusion percentage of myoblasts, dystrophic myoblasts tended to fuse earlier than normal ones, especially after 5 days in culture. The findings of this study are valuable in understanding the myogenesis of myoblasts under different culture conditions. The establishment of requirements for good growth of myoblast cultures will facilitate myoblast transfer therapy. Finally, the growth characteristics of normal and dystrophic myoblasts as well as variances in the proliferation and differentiation of these two types of cells are clarified.

Performance of older adults with and without cerebrovascular accident on the test of visual-perceptual skills

OBJECTIVES

The purposes of this study were to (a) investigate whether older subjects with brain damage score lower on the Test of Visual-Perceptual Skills (TVPS) than control subjects without brain damage matched for age and education, (b) determine the demographic effects on test performance in both groups, and (c) determine the capacity of TVPS in identifying visual-perceptual deficits in adults with brain damage.

METHOD

The study sample consisted of 22 subjects with cerebrovascular accident (CVA) and 155 subjects who were neurologically intact (control group). The TVPS was administered individually to each subject. Raw scores (total response time and accuracy) were analyzed to generate descriptive statistics. Other statistical analysis included analysis of variance, analysis of covariance, discriminant analysis, and Pearson product-moment correlations.

RESULTS

There were significant between-group differences on all TVPS measures, with control subjects performing better than subjects with CVA. Age was shown to affect performance on most subtests of the TVPS in the control group. Education had significant influence over each measure, whereas gender differences were significant only in two subtests. No demographic effects were found in the group with CVA. The total TVPS accuracy score was the most powerful discriminator between the two groups, correctly classifying 74.4% of the subjects. Finally, the total accuracy score inversely correlated with total time score.

CONCLUSION

The TVPS may be useful in screening for visual-perceptual impairments in adults with CVA. Age, gender, and educational level have no significant impact on the magnitude of visual-perceptual dysfunctions.

Primary culture of mouse myoblasts

The literature has revealed variations in the protocols for myoblast cultures, and little information is available on myoblast and fibroblast proliferation. Therefore, the purposes of this study were to establish a prudent protocol for myoblast cultures by comparing a variety of culturing procedures used in previous research and to quantitate myoblast proliferation and fusion under different culture conditions. In addition, the growth status of myoblasts and fibroblasts was investigated. Results indicate that the requirements for an ideal myoblast culture should include a combined enzyme of 0.25% trypsin and 0.2% collagenase type IV (1:1), a preplating time of approximately 15-20 minutes, and a seeding density at 1 x 10(5) cells/ml. Furthermore, the mouse sample should be those of newborns. A better proliferative capacity of myoblasts was noted in an incubator of 10% CO2, coupled with Dulbecco's MEM plus 15% fetal calf serum. The doubling times of myoblasts were shorter than those of fibroblasts, and myoblast number reached its highest at 4 and 5 days. The findings of this study are valuable in understanding the growth status of myoblasts and fibroblasts in primary cultures. Moreover, the establishment of requirements for a good growth of myoblast cultures will facilitate myoblast transfer therapy.

A study of pinch strength in normal Taiwanese adults

The purpose of this study was to describe norms of pinch strength for normal Taiwanese adults and to investigate the effects of age, gender, height, weight, and digit length on pinch strength. Three types of pinch (i.e. tip, key, and palmar pinch) were measured for a sample of 356 adults aged 20 to 88 years from a major metropolitan city located in southern Taiwan. A newly calibrated B&L pinch gauge was used for strength measurements with a standardized position during testing. The dominant hand was tested first, followed by the nondominant hand. The average of two trials for each pinch strength test was used as the subject's test scores. The results indicated that in the male group, pinch strength remained relatively stable up to 50 to 59 years old before a decline began, whereas pinch strength peaked with the 40- to 59-year-old group for female subjects. Males were stronger than females on all prehension patterns. Pinch strength of the right hand was significantly affected by such variables as the lengths of thumb and index finger and height, along with weight. With regard to the left hand, only height and weight had significant impact on pinch strength. Finally, there was an overall 13% pinch strength difference between the dominant and nondominant hands for the total sample. These findings provide therapists with objective data concerning the pinch strength of the Taiwanese adult's hand for clinical use.

Mixed estrogenic and anti-estrogenic activities of yuehchukene--a bis-indole alkaloid

Anti-estrogenic effects of yuehchukene were observed in rat uterotrophic, mice vaginal smear and MCF-7 cell growth assays. Whereas yuehchukene per se was estrogenic in these bioassay models, the co-administration of yuehchukene and an optimal dose of 3,17 beta-estradiol (estradiol) could attenuate the maximum estrogenic response due to estradiol alone. The anti-estrogenic effect of yuehchukene in rat uterine hypertrophy was corroborated by a parallel attenuation of ornithine decarboxylase activity in these tissues. Yuehchukene binds to rat, mice and MCF-7 cell estrogen receptors with a relative binding affinity of 1/150 to 1/300. This binding affinity was positively related to estrogenicity as determined by uterotrophic assay and MCF-7 cell growth. However, this estrogenic effect did not correlate with the degree of competitive receptor binding by a weaker agonist. Indole-3-carbinol and methylbutadienylindole could induce ethoxyresorufin O-deethylase and estradiol-2-hydroxylase in rat liver and MCF-7 cells. It is postulated that the 'free' indole moiety of yuehchukene could possess similar induction activity. Thus yuehchukene may have a dual pharmacological function. While the intact molecule is a weak estrogen, the 'free' indole moiety in yuehchukene may induce an enhancement of estradiol-2-hydroxylase, thus terminating the biological activity of the endogenous estrogen pool. There is obvious benefit in attenuating the estrogen level in post-menopausal breast cancer patients without going directly to the use of tamoxifen or aromatase inhibitor. Yuehchukene may serve this purpose. In this context, the pharmacological evaluation of a hydroxylated yuehchukene analogue and the anti-estrogenic effect of methylbutadienylindole acid-condensation products are now being studied in earnest.

Response to supplementary vaccination with recombinant or plasma hepatitis B vaccine in healthy non-responding children

Fifty-three children who failed to respond to four doses of plasma hepatitis B (HB) vaccine (anti-HBs titre < 10 IU l-1) were divided into two groups and received revaccination with either three doses of recombinant HB vaccine (10 micrograms/dose, by 0, 1, 6 month schedule; group A) or two additional doses of plasma HB vaccine (5 micrograms/dose, by 0, 1 month schedule; group B) respectively. Thirty-two vaccinees in group A had a response rate (with anti-HBs > 10 IU l-1) of 53.1% (17/32), 87.5% (28/32), and 100% (32/32) after first, second and third doses of the vaccine respectively. Twenty-one vaccinees in group B had a response rate of 61.9% (13/21) after two additional doses of plasma vaccine. High anti-HBs titres (> 1000 IU l-1) were noted in 50% of the vaccinees in group A after three doses of vaccine. Comparing anti-HBs response between group A and group B after two additional doses of HB vaccine, group A had a higher anti-HBs titre (geometric mean titre 104.7 IU l-1 versus 75.9 IU l-1) along with a better seroconversion rate (87.5 versus 61.9%). However, the differences in vaccine dose between the two groups may also be a contributory factor. Our findings indicate that three doses of recombinant HB vaccine were invariably effective in eliciting a good immune response in previous non-responders to the four doses of plasma HB vaccine. Therefore, it is speculated that these young vaccinees who did not respond to four doses of plasma HB vaccine may not be real non-responders, but hyporesponders.

Grip strength in different positions of elbow and shoulder

This study investigated the effect of shoulder position on grip strength in 80 men and 80 women. A Jamar dynamometer was used to measure the grip strength in the four testing positions. The four hand strength tests consisted of three positions in which the elbow was maintained in full extension combined with varying degrees of shoulder flexion (ie, 0 degrees, 90 degrees, and 180 degrees) and of one position in which the elbow was flexed at 90 degrees with the shoulder in 0 degrees of flexion. Only the dominant hand was tested. The highest mean grip strength measurement was recorded when the shoulder was positioned at 180 degrees of flexion with elbow in full extension; whereas the position of 90 degrees elbow flexion with shoulder in 0 degrees of flexion had the lowest grip strength score. In addition, the grip strength measured with the elbow in extension, regardless of shoulder position (ie, 0 degrees, 90 degrees, and 180 degrees of flexion), was significantly higher than when the elbow was flexed at 90 degrees with the shoulder positioned at 0 degrees of flexion. Finally, grip strength differed significantly for both sexes and for each age group. The grip values of the standardized 90 degrees elbow flexed position were further analyzed to determine the average performances in the study population. For men, grip strength peaked within the 20 to 39 years age group and gradually declined thereafter. For women, the highest mean grip strength measurement was recorded in the 40- to 49-year-old age group and then deteriorated with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Performance of normal Chinese adults on grip strength test: a preliminary study

This study investigated grip strength performance in normal Chinese adults. Grip strength of 160 Chinese subjects (80 males and 80 females) from a major metropolitan city in southern Taiwan was measured with a newly calibrated Jamar dynamometer. The subject was tested in a standing position, with shoulder adducted and neutrally rotated, elbow flexed at 90 degrees and forearm and wrist in neutral position. Subjects exerted one maximal effort with both right and left hands. Results indicate that the grip strength of Chinese males peaked within the 20 to 39 year-old group. For Chinese females, the highest grip strength score occurred in the 40 to 49 year-old age group and declined as a function of age. Males consistently had higher grip strength than females across age ranges. Finally, there was no 10% variance in grip strength from the dominant to nondominant hand for each age group of both sexes. Instead, there were 49 (31%) of all subjects who had nondominant hand strength scores that were equal to or greater than their dominant hand strength scores. Clinical implications and recommendations for future research are suggested.

Severe hypertension in hypoplastic kidney and bilateral renal artery stenosis: report of one case

A three year-old boy was found incidentally to have severe hypertension (around 200/110 mmHg) when he was brought to This Hospital's Emergency Department because of his abdominal pain. After his admission, serial and detailed examinations were performed. These included: basic blood chemistry studies, abdominal and renal sonography, excretory urography, radionuclide scintigraphy and angiography with selective renal vein renin sampling. Diagnosis was made of renovascular hypertension with combination of unilateral renal hypoplasia and bilateral renal artery stenosis. The patient was given oral anti-hypertensive drugs, with resulting satisfactorily controlled blood pressure after two weeks of treatment. He was discharged without surgical intervention.