Depression trajectories and obesity among the elderly in Taiwan.

BACKGROUND: The present study aimed to (a) characterize 10-year trajectory patterns of depressive symptoms and (b) investigate the association between depressive trajectory and subsequent obesity, metabolic function and cortisol level. METHOD: In a prospective study of Taiwanese adults aged ≥60 years (n=3922) between 1989 and 1999, depression was assessed using a 10-item short-form of the Center for Epidemiologic Studies Depression Scale and information on body mass index (BMI) was collected by self-report. A subsample (n=445) of the original cohort in 1989 was drawn to assess metabolic variables and cortisol levels in a 2000 follow-up. After trajectory analyses were performed, multinomial logistic regression analyses were used to estimate the association estimates. RESULTS: We identified four distinctive trajectories of depressive symptoms: class 1 (persistent low, 41.8%); class 2 (persistent mild, 46.8%); class 3 (late peak, 4.2%); and class 4 (high-chronic, 7.2%). The results from both complete cases and multiple imputation analyses indicated that the odds of obesity were lower in the class 2, 3 or 4 elderly, as compared with those in class 1, while the odds of underweight were higher. The classes of older adults with more and persistent depressive symptoms showed a trend toward having both a lower BMI (p=0.01) and a higher cortisol level (p=0.04) compared with those with low depressive symptoms. CONCLUSIONS: Incremental increases in depressive symptoms over time were associated with reduced risk of obesity and higher cortisol levels.

Toll-like receptor 2 deficiency improves insulin sensitivity and hepatic insulin signalling in the mouse.

AIMS/HYPOTHESIS: Substantial evidence suggests a link between elevated inflammation and development of insulin resistance. Toll-like receptor 2 (TLR2) recognises a large number of lipid-containing molecules and transduces inflammatory signalling in a variety of cell types, including insulin-responsive cells. Considering the contribution of the fatty acid composition in TLR2-depedent signalling, we hypothesised that the inflammatory signals transduced by TLR2 contribute to insulin resistance. METHODS: Mice deficient in TLR2 were used to investigate the in vivo roles of TLR2 in initiating and maintaining inflammation-associated insulin resistance and energy homeostasis. RESULTS: We first recapitulated the observation with elevated expression of TLR2 and inflammatory cytokines in white adipose tissue and liver of ob/ob mice. Aged or high-fat-fed TLR2-deficient mice were protected from obesity and adipocyte hypertrophy compared with wild-type mice. Moreover, mice lacking TLR2 exhibited improved glucose tolerance and insulin sensitivity regardless of feeding them regular chow or a high-fat diet. This is accompanied by reductions in expression of inflammatory cytokines and activation of extracellular signal-regulated kinase (ERK) in a liver-specific manner. The attenuated hepatic inflammatory cytokine expression and related signalling are correlated with increased insulin action specifically in the liver in TLR2-deficient mice, reflected by increased insulin-stimulated protein kinase B (Akt) phosphorylation and IRS1 tyrosine phosphorylation and increased insulin-suppressed hepatocyte glucose production. CONCLUSIONS/INTERPRETATION: The absence of TLR2 attenuates local inflammatory cytokine expression and related signalling and increases insulin action specifically in the liver. Thus, our work has identified TLR2 as a key mediator of hepatic inflammation-related signalling and insulin resistance.

Nonlinear modelling of cancer: bridging the gap between cells and tumours.

Despite major scientific, medical and technological advances over the last few decades, a cure for cancer remains elusive. The disease initiation is complex, and including initiation and avascular growth, onset of hypoxia and acidosis due to accumulation of cells beyond normal physiological conditions, inducement of angiogenesis from the surrounding vasculature, tumour vascularization and further growth, and invasion of surrounding tissue and metastasis. Although the focus historically has been to study these events through experimental and clinical observations, mathematical modelling and simulation that enable analysis at multiple time and spatial scales have also complemented these efforts. Here, we provide an overview of this multiscale modelling focusing on the growth phase of tumours and bypassing the initial stage of tumourigenesis. While we briefly review discrete modelling, our focus is on the continuum approach. We limit the scope further by considering models of tumour progression that do not distinguish tumour cells by their age. We also do not consider immune system interactions nor do we describe models of therapy. We do discuss hybrid-modelling frameworks, where the tumour tissue is modelled using both discrete (cell-scale) and continuum (tumour-scale) elements, thus connecting the micrometre to the centimetre tumour scale. We review recent examples that incorporate experimental data into model parameters. We show that recent mathematical modelling predicts that transport limitations of cell nutrients, oxygen and growth factors may result in cell death that leads to morphological instability, providing a mechanism for invasion via tumour fingering and fragmentation. These conditions induce selection pressure for cell survivability, and may lead to additional genetic mutations. Mathematical modelling further shows that parameters that control the tumour mass shape also control its ability to invade. Thus, tumour morphology may serve as a predictor of invasiveness and treatment prognosis.

Predicting risk for early infantile atopic dermatitis by hereditary and environmental factors.

BACKGROUND: Hereditary and environmental factors contribute to the occurrence of atopic dermatitis (AD). However, the interaction of these two factors is not totally understood. OBJECTIVES: To evaluate the early risk factors for infantile AD at the age of 6 months and to develop a predictive model for the development of AD. METHODS: In 2005, a representative sample of mother and newborn pairs was obtained by multistage, stratified systematic sampling from the Taiwan national birth register. Information on hereditary and environmental risk factors was collected by home interview when babies were 6 months old. Multivariate regression analysis was applied to determine the risk factors for AD in the infants. RESULTS: A total of 20 687 pairs completed the study satisfactorily. AD was diagnosed in 7.0% of 6-month-old infants by physicians. Parental asthma, atopic dermatitis and allergic rhinitis, and maternal education levels were risk factors for AD in infants. Among environmental factors, fungus on walls at home and renovation/painting in the house during pregnancy were significantly associated with early infantile AD. Using these factors, the probability of having infantile AD was estimated and grouped into low, high and very high. With five runs of tests in mutually exclusive subsets of this population, the likelihood of AD for 6-month-old infants was consistent in all the groups with the predictive model. The highest predicted probability of AD was 70.1%, among boys with maternal education levels > 12 years, both parents with AD, renovation and painting of the house during pregnancy and fungus on walls at home. The lowest probability was 3.1%, among girls with none of the above factors. CONCLUSIONS: This investigation provides a technique for predicting the risk of infantile AD based on hereditary and environmental factors, which could be used for developing a preventive strategy against AD, especially among those children with a family history of atopy.

Environmental risk factors for early infantile atopic dermatitis.

Previous studies of predictors of atopic dermatitis (AD) in Asia have had limited sample size and small numbers of variables focused primarily on family history or dietary exposures. The purpose of this study was to evaluate the influence of various environmental risk factors for early infantile AD. We used multistage, stratified systematic sampling to recruit 2048 mother-child pairs from the Taiwan national birth registration in 2003. Information on environmental risk factors for infant AD gathered by questionnaire were available from 1760 infants at 6 months of age. Multiple logistic regression was used to estimate adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) for risk factors for AD after adjusting for potential confounders. AD was noted in 118 of 1760 (6.7%) of the infants. After adjusting for maternal age and education, family history of atopy, infant gender, and gestational age, fungi on walls of the house [aOR 2.14 (95% CI 1.41-3.22)] and frequent use of microwave oven at home [aOR 1.71 (95% CI 1.13-2.58)] increased the risk of early infantile AD. This study suggests that environmental factors do play a role in early infantile AD. Fungi, a kind of aeroallergen, are especially important in humid climate as in Taiwan and their impacts might be felt at the early infant stage. The hazards of microwave use should be paid more attention.

Posterior epidural migration of a sequestrated lumbar disk fragment: MR imaging findings.

We present a 75-year-old man who, for 2 weeks, had progressive pain in both of his thighs when standing straight. MR imaging showed a sequestrated disk fragment, which had a signal intensity similar to that of a herniated disk with a rim enhancement in the posterior epidural space and a ruptured outermost annulus of the intervertebral disk at L2-3. Awareness of these MR imaging findings can help in the diagnosis of posterior epidural disk migration.

Self-propelled particles with soft-core interactions: patterns, stability, and collapse.

Understanding collective properties of driven particle systems is significant for naturally occurring aggregates and because the knowledge gained can be used as building blocks for the design of artificial ones. We model self-propelling biological or artificial individuals interacting through pairwise attractive and repulsive forces. For the first time, we are able to predict stability and morphology of organization starting from the shape of the two-body interaction. We present a coherent theory, based on fundamental statistical mechanics, for all possible phases of collective motion.

Activation of nuclear factor kappaB in hepatitis C virus infection: implications for pathogenesis and hepatocarcinogenesis.

The hepatitis C virus (HCV) core protein is a multifunctional protein. It may bind to the death domain of tumor necrosis factor receptor 1 (TNFR1) and to the cytoplasmic tail of lymphotoxin-beta receptor, implying that it may be involved in the apoptosis and anti-apoptosis signaling pathways. In vitro studies have been inconclusive regarding its ability to inhibit or enhance TNF-alpha-induced apoptosis. To address this issue, electrophoretic mobility shift assay (EMSA) and immunohistochemical studies were used to show the activation of nuclear factor kappaB (NF-kappaB) in HCV-infected liver tissues and in HCV core-transfected cells. The activation of NF-kappaB was correlated with the apoptosis assays. The results showed that NF-kappaB activation could be shown in HCV-infected livers and HCV core-transfected cells. The data of EMSA correlated with those of immunohistochemical studies, which revealed a higher frequency of NF-kappaB nuclear staining in HCV-infected than in normal livers. NF-kappaB activation conferred resistance to TNF-alpha-induced apoptosis in HCV core-transfected cells. Inhibition of NF-kappaB activation by pyrrolidine dithiocarbamate sensitized them to TNF-alpha-induced apoptosis. These findings suggest that HCV infection may cause anti-apoptosis by activation of NF-kappaB and implicate a mechanism by which HCV may evade the host's immune surveillance leading to viral persistence and possibly to hepatocarcinogenesis.

Stress, social relations, and old age mortality in Taiwan.

The research analyzed the relationships among stress, social relations, and mortality in a probability sample of 4,049 Taiwanese adults, aged 60 and over. The baseline survey was conducted in 1989 and the survival status of the respondents was ascertained during the subsequent 4 years. Death of a spouse or a child was found to increase the risk of dying directly and indirectly, whereas major financial difficulty during the past 5 years and current financial strain influenced mortality indirectly through their effects on self-rated health disability. In addition to their direct effect on mortality, martial status and work status lowered the probability of dying through decreased disability and subjective ill health. Finally, no buffering effects of social support were substantiated.

Educational attainment and transitions in functional status among older Taiwanese.

Despite considerable research examining the influence of socioeconomic status on health, few studies have considered this relationship as it pertains to older adults in non-Western societies. We attempt to ascertain the influence of education on changes in physical functioning in a rapidly developing country. Data come from the 1989 Survey of Health and Living Status of the Elderly in Taiwan and a follow-up interview in 1993 (N = 4,049, age = 60+). Individuals are conceptualized to be in a state of functional independence or functional limitation at the time of origin, based on their ability to perform three physical functioning tasks. The outcome at the follow-up interview is categorized as functionally independent, limited, or dead, allowing for six probabilities, one from each state of origin to each outcome. These are calculated using a multinomial logit model, controlling for other factors often thought to be associated with health transitions. High levels of educational attainment result in a decreased incidence of functional limitation for those originating in a state of independence. Contrary to expectations, however, education has little influence on those who originate functionally limited. Thus, higher education plays a substantial role in primary prevention of morbidity, delaying the onset of disability, but other factors are more important once limitations begin. We speculate on the reasons behind these findings, including that the results may be culturally dependent.

The effect of education on mortality among older Taiwanese and its pathways.

The present research examines the impact of education on the mortality of older Taiwanese during a 4-year interval from April 1989 to April 1993. Data used for this study come from the Taiwan Survey of Health & Living Status of the Elderly (1989). The research decomposes the effect of education into the direct effect and the indirect effects by means of health status, health behaviors, and social relationships. We have shown that, of the total effect of educational attainment on the mortality of older Taiwanese, about 83% represents indirect influences by means of the 3 mediating factors, particularly health status. On the other hand, the magnitude of the direct effect, which might reflect influences of additional intervening variables on old-age mortality, is low and not statistically significant. The results demonstrate that the apparent strong effect of education on mortality among older Taiwanese can be accounted for parsimoniously through 3 major pathways.

Sex, marital status, and psychological distress in later life: a comparative analysis.

Some investigators maintain that while married men experience less distress than married women, the opposite may be true for those who are not married. In this instance, women are thought to report fewer symptoms of distress than men. The purpose of this study is to examine the relationships among gender, marital status, psychological distress and alcohol use in five culturally-diverse groups of older adults: U.S. whites, U.S. blacks, Japanese, Taiwanese and elderly people in the People's Republic of China. We find little evidence of the pattern described above. Instead, the data suggest that being single is equally detrimental for older men and women regardless of the cultural setting.