Clostridium difficile toxin B (TcdB) intoxicates target cells by glucosylating Rho GTPases. TcdB (269 kDa) consists of at least 4 functional domains including a glucosyltransferase domain (GTD), a cysteine protease domain (CPD), a translocation domain (TD), and a receptor binding domain (RBD). The function and molecular mode of action of the TD, which is the largest segment of TcdB and comprises nearly 50% of the protein, remain largely unknown. Here we show that a 97-amino-acid segment (AA1756 – 1852, designated as ?97 or D97), located in the C-terminus of the TD and adjacent to the RBD, is essential for the cellular activity of TcdB. Deletion of this segment in TcdB (designated as TxB-D97), did not adversely alter toxin enzymatic activities or its cellular binding and uptake capacity. TxB-D97 bound to and entered cells in a manner similar to TcdB holotoxin. Both wild type and mutant toxins released their GTDs similarly in the presence of inositol hexakisphosphate (InsP6), and showed a similar glucosyltransferase activity in a cell-free glucosylating assay. Despite these similarities, the cytotoxic activity of TxB-D97 was reduced by more than 5 logs compared to wild type toxin, supported by the inability of TxB-D97 to glucosylate Rac1 of target cells. Moreover, the mutant toxin failed to elicit tumor necrosis factor alpha (TNF-α) in macrophages, a process dependent on the glucosyltransferase activity of the toxin. Cellular fractionation of toxin-exposed cells revealed that TxB-D97 was unable to efficiently release the GTD into cytosol. Thereby, we conclude the 97-amino-acid region of the TD C-terminus of TcdB adjacent to the RBD, is essential for the toxicity of TcdB.
The purpose of this study was to investigate the typical development of postural control in younger (5–6 yrs) and older (7–16 yrs) children (YTD and OTD) during two gait tasks, including level walking and obstacle-crossing, using a dual-task paradigm, and to compare the results of the children’s performance with that of healthy young adults (HYA). Our findings revealed that gait control in typical children requires attentional resources to maintain stability. Moreover, dual-task interference was less in HYA compared to YTD and OTD. Gait performance decrements in the dual-task context were greater in YTD compared to OTD, whereas cognitive performance decrements in YTD and OTD were similar. In addition, dual-tasking affected cognitive performance more in YTD when gait task difficulty was increased. Results suggest a developmental trend in attentional resources used to control gait in typical children. Postural control during gait under dual-task conditions was improved when children were more mature, as attentional resources increased with age.
The association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and hepatocellular carcinoma (HCC) risk was inconsistent and underpowered. To clarify the effects of MTHFR gene polymorphisms on the risk of HCC, a meta-analysis of all available studies relating C677T and/or A1298C polymorphisms of MTHFR gene to the risk of HCC was conducted.
The authors searched PubMed, EMBASE, Cochrane Library, Web of Science, and Chinese Biomedical Literature database (CBM) for the period up to July 2012. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity.
Finally, 12 studies with 2,351 cases and 4,091 controls were included for C677T polymorphism and 6 studies with 1,333 cases and 1,878 controls were included for A1298C polymorphism. With respect to A1298C polymorphism, significantly decreased HCC risk was found in the overall population (CC vs. AA: OR = 0.660, 95%CI 0.460–0.946, P = 0.024; recessive model: OR = 0.667, 95%CI = 0.470–0.948, P = 0.024). In subgroup analyses, significantly decreased HCC risk was found in Asian population (CC vs. AA: OR = 0.647, 95%CI = 0.435–0.963; P = 0.032) and population-based studies (CC vs. AA: OR = 0.519, 95%CI = 0.327–0.823; P = 0.005). With respect to C677T polymorphism, no significant association with HCC risk was demonstrated in overall and stratified analyses.
We concluded that MTHFR A1298C polymorphism may play a protective role in the carcinogenesis of HCC. Further large and well-designed studies are needed to confirm this association.
The global emergence of Clostridium difficile infection (CDI) has contributed to the recent surge in severe antibiotic-associated diarrhea and colonic inflammation. C. difficile produces two homologous glucosylating exotoxins, TcdA and TcdB, both of which are pathogenic and require neutralization to prevent disease occurrence. However, because of their large size and complex multifunctional domain structures, it has been a challenge to produce native recombinant toxins that may serve as vaccine candidates. Here, we describe a novel chimeric toxin vaccine that retains major neutralizing epitopes from both toxins and confers complete protection against primary and recurrent CDI in mice. Using a nonpathogenic Bacillus megaterium expression system, we generated glucosyltransferase-deficient holotoxins and demonstrated their loss of toxicity. The atoxic holotoxins induced potent antitoxin neutralizing antibodies showing little cross-immunogenicity or protection between TcdA and TcdB. To facilitate simultaneous protection against both toxins, we generated an active clostridial toxin chimera by switching the receptor binding domain of TcdB with that of TcdA. The toxin chimera was fully cytotoxic and showed potent proinflammatory activities. This toxicity was essentially abolished in a glucosyltransferase-deficient toxin chimera, cTxAB. Parenteral immunization of mice or hamsters with cTxAB induced rapid and potent neutralizing antibodies against both toxins. Complete and long-lasting disease protection was conferred by cTxAB vaccinations against both laboratory and hypervirulent C. difficile strains. Finally, prophylactic cTxAB vaccination prevented spore-induced disease relapse, which constitutes one of the most significant clinical issues in CDI. Thus, the rational design of recombinant chimeric toxins provides a novel approach for protecting individuals at high risk of developing CDI.
Ctip2 is crucial for epidermal homeostasis and protective barrier formation in developing mouse embryos. Selective ablation of Ctip2 in epidermis leads to increased transepidermal water loss (TEWL), impaired epidermal proliferation, terminal differentiation, as well as altered lipid composition during development. However, little is known about the role of Ctip2 in skin homeostasis in adult mice.
To study the role of Ctip2 in adult skin homeostasis, we utilized Ctip2ep−/− mouse model in which Ctip2 is selectively deleted in epidermal keratinocytes. Measurement of TEWL, followed by histological, immunohistochemical, and RT-qPCR analyses revealed an important role of Ctip2 in barrier maintenance and in regulating adult skin homeostasis. We demonstrated that keratinocytic ablation of Ctip2 leads to atopic dermatitis (AD)-like skin inflammation, characterized by alopecia, pruritus and scaling, as well as extensive infiltration of immune cells including T lymphocytes, mast cells, and eosinophils. We observed increased expression of T-helper 2 (Th2)-type cytokines and chemokines in the mutant skin, as well as systemic immune responses that share similarity with human AD patients. Furthermore, we discovered that thymic stromal lymphopoietin (TSLP) expression was significantly upregulated in the mutant epidermis as early as postnatal day 1 and ChIP assay revealed that TSLP is likely a direct transcriptional target of Ctip2 in epidermal keratinocytes.
Our data demonstrated a cell-autonomous role of Ctip2 in barrier maintenance and epidermal homeostasis in adult mice skin. We discovered a crucial non-cell autonomous role of keratinocytic Ctip2 in suppressing skin inflammatory responses by regulating the expression of Th2-type cytokines. It is likely that the epidermal hyperproliferation in the Ctip2-lacking epidermis may be secondary to the compensatory response of the adult epidermis that is defective in barrier functions. Our results establish an initiating role of epidermal TSLP in AD pathogenesis via a novel repressive regulatory mechanism enforced by Ctip2.
People worldwide depend upon daily fish consumption as a major source of protein and other nutrients. Fish are high in nutrients essential for normal brain development, but they also contain methylmercury (MeHg), a neurotoxicant. Our studies in a population consuming fish daily have indicated no consistent pattern of adverse associations between prenatal MeHg and children’s development. For some endpoints we found performance improved with increasing prenatal exposure to MeHg. Follow up studies indicate this association is related to the beneficial nutrients present in fish.
To determine if the absence of adverse outcomes and the presence of beneficial associations between prenatal MeHg and developmental outcomes previously reported persists into adolescence.
This study was conducted on the Main Cohort of the Seychelles Child Development Study (SCDS). We examined the association between prenatal MeHg exposure and subjects’ performance at 17 years of age on 27 endpoints. The test battery included the Wisconsin Card Sorting Test (WCST), the California Verbal Learning Test (CVLT), the Woodcock-Johnson (W-J-II) Achievement Test, subtests of the Cambridge Neuropsychological Test Automated Battery (CANTAB), and measures of problematic behaviors. Analyses for all endpoints were adjusted for postnatal MeHg, sex, socioeconomic status, maternal IQ, and child’s age at testing and the child’s IQ was added for problematic behavioral endpoints.
Mean prenatal MeHg exposure was 6.9 ppm. There was no association between prenatal MeHg and 21 endpoints. Increasing prenatal MeHg was associated with better scores on four endpoints (higher W-J-II math calculation scores, reduced numbers of trials on the Intra-Extradimensional Shift Set of the CANTAB, fewer reports of substance use and incidents of and referrals for problematic behaviors in school. Increasing prenatal MeHg was adversely associated with one level of referrals to a school counselor.
At age 17 years there was no consistent pattern of adverse associations present between prenatal MeHg exposure and detailed domain specific neurocognitive and behavioral testing. There continues to be evidence of improved performance on some endpoints as prenatal MeHg exposure increases in the range studied, a finding that appears to reflect the role of beneficial nutrients present in fish as demonstrated previously in younger subjects. These findings suggest that ocean fish consumption during pregnancy is important for the health and development of children and that the benefits are long lasting.
Catechol-O-methyltransferase (COMT) is one of the most important enzymes involved in estrogen metabolism and its functional genetic polymorphisms may be associated with breast cancer (BC) risk. Many epidemiological studies have been conducted to explore the association between the COMT Val158Met polymorphism and breast cancer risk. However, the results remain inconclusive. In order to derive a more precise estimation of this relationship, a large meta-analysis was performed in this study.
Systematic searches of the PubMed, Embase and Cochrane Library were performed. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.
A total of 56 studies including 34,358 breast cancer cases and 45,429 controls were included. Overall, no significant associations between the COMT Val158Met polymorphism and breast cancer risk were found for LL versus HH, HL versus HH, LL versus HL, recessive model LL versus HL+HH, and dominant model LL+HL versus HH. In subgroup analysis by ethnicity, source of controls, and menopausal status, there was still no significant association detected in any of the genetic models.
Our meta-analysis results suggest that the COMT Val158Met polymorphism may not contribute to breast cancer susceptibility.
The virtual slides(s) for this article can be found here:
COMT; Polymorphism; Breast cancer; Meta-analysis
Aberrant DNA methylation plays important roles in carcinogenesis. However, the functional significance of genome-wide hypermethylation and hypomethylation of gene promoters in carcinogenesis currently remain unclear.
Based on genome-wide methylation data for five cancer types, we showed that genes with promoter hypermethylation were highly consistent in function across different cancer types, and so were genes with promoter hypomethylation. Functions related to “developmental processes” and “regulation of biology processes” were significantly enriched with hypermethylated genes but were depleted of hypomethylated genes. In contrast, functions related to “cell killing” and “response to stimulus”, including immune and inflammatory response, were associated with an enrichment of hypomethylated genes and depletion of hypermethylated genes. We also observed that some families of cytokines secreted by immune cells, such as IL10 family cytokines and chemokines, tended to be hypomethylated in various cancer types. These results provide new hints for understanding the distinct functional roles of genome-wide hypermethylation and hypomethylation of gene promoters in carcinogenesis.
Genes with promoter hypermethylation and hypomethylation are highly consistent in function across different cancer types, respectively, but these two groups of genes tend to be enriched in different functions associated with cancer. Especially, we speculate that hypomethylation of gene promoters may play roles in inducing immunity and inflammation disorders in precancerous conditions, which may provide hints for improving epigenetic therapy and immunotherapy of cancer.
Objective: Retrovirus has been suggested as one of agents involved in the development of schizophrenia. In the present study, we examined the role of the human endogenous retrovirus W family (HERV-W) env gene in the etiopathogenesis of recent-onset schizophrenia, using molecular and epidemiological approaches. Methods: Nested RT-PCR was used to detect the messenger RNA (mRNA) of the HERV-w env gene in plasmas. Quantitative real-time polymerase chain reaction (PCR) was employed to detect the viral reverse transcriptase activity in human sera. Human U251 glioma cells were used to study the potential role of the HERV-W env gene in the etiopathogenesis of recent-onset schizophrenia. Results: We identified genes with mRNA sequences homologous to HERV-W env gene from plasmas of 42 out of 118 individuals with recent-onset schizophrenia but not from any of 106 normal persons (P < .01, t test). Quantitative real-time PCR showed a significantly increase in the reverse transcriptase activity in the sera of patients (by 35.59%) compared with controls (by 2.83%) (P < .05, t test). Overexpression of HERV-w env in human U251 glioma cells upregulated brain-derived neurotrophic factor (BDNF), an important schizophrenia-associated gene, neurotrophic tyrosine kinase receptor type 2 (NTRK2, also called TrkB), and dopamine receptor D3 and increased the phosphorylation of cyclic adenosine monophosphate response element–binding (CREB) protein. BDNF promoter reporter gene assays showed that the HERV-W env triggers BDNF production in human U251 glioma cells. Using gene knockdown, we found that CREB is required for the expression of BDNF that is regulated by env. Conclusion: Our data revealed that the transcriptional activation of HERV is associated with the development of schizophrenia in some patients and indicated that HERV-W env regulates the expression of schizophrenia-associated genes. This report is the first to elucidate the signaling pathway responsible for the upregulation of HERV-W env–triggered BDNF. Our study provides new evidence for the involvement of HERV-W in the central nervous system, which will benefit the diagnosis and treatment of the devastating schizophrenia and related disorders.
schizophrenia; HERV-W; env; Human U251 glioma cells; DRD3; BDNF; siRNA
Metastasis is the primary cause of death for cancer patients. TWIST1, an evolutionarily conserved basic helix-loop-helix (bHLH) transcription factor, is a strong promoter of metastatic spread and its expression is elevated in many advanced human carcinomas. However, the molecular events triggered by TWIST1 to motivate dissemination of cancer cells are largely unknown.
Here we show that TWIST1 induces the production of interleukin 8 (IL8), which activates matrix metalloproteinases and promotes invasion of breast epithelial and cancer cells. In this novel mechanism, TWIST1-mediated IL8 transcription is induced through the TWIST1 carboxy-terminal WR (Trp-Arg) domain instead of the classic DNA binding bHLH domain. Co-immunoprecipitation analyses revealed that the WR domain mediates the formation of a protein complex comprised of TWIST1 and the nuclear factor-kappaB (NF-κB) subunit RELA (p65/NF-κB3), which synergistically activates the transcriptional activity of NF-κB. This activation leads to increased DNA binding affinity of RELA to the IL8 promoter and thus induces the expression of the cytokine. Blockage of IL8 signaling by IL8 neutralizing antibodies or receptor inhibition reduced the invasiveness of both breast epithelial and cancer cells, indicating that TWIST1 induces autonomous cell invasion by establishing an IL8 antocrine loop.
Our data demonstrate that the TWIST1 WR domain plays a critical role in TWIST1-induced IL8 expression through interactions with and activation of NF-κB. The produced IL8 signals through an autocrine loop and promotes extracellular matrix degradation to enable cell invasion across the basement membrane.
TWIST1; WR domain; RELA; NF-κB; IL8
There is accumulating evidence to implicate the importance of EphBs receptors and ephrinBs ligands were involved in modulation of spinal nociceptive information. However, the downstream mechanisms that control this process are not well understood. In the present study, we investigated whether phosphatidylinositol 3-kinase (PI3K), as the downstream effectors, participates in modulation of spinal nociceptive information related to ephrinBs/EphBs. Intrathecal injection of ephrinB1-Fc produced a dose- and time-dependent thermal and mechanical hyperalgesia, accompanied by the increase of spinal PI3K-p110γ, phosphorylation of AKT (p-AKT) and c-Fos expression. Pre-treatment with PI3K inhibitor wortmannin or LY294002 prevented activation of spinal AKT induced by ephrinB1-Fc. Inhibition of spinal PI3K signaling dose-dependently prevented and reversed pain behaviors and spinal c-Fos protein expression induced by intrathecal injection of ephrinB1-Fc. Inhibition of EphBs receptors by intrathecal injection of EphB1-Fc reduced formalin-induced inflammation and chronic constrictive injury-induced neuropathic pain behaviors accompanied by decreased expression of spinal PI3K,p-AKT and c-Fos protein. Furthermore, pre-treatment with PI3K inhibitor wortmannin or LY294002 prevented ephrinB1-Fc-induced ERK activation in spinal. These data demonstrated that PI3K and PI3K crosstalk to ERK signaling contributed to modulation of spinal nociceptive information related to ephrinBs/EphBs.
Cigarette smoking is associated with increased cardiovascular morbidity and mortality in the general population, but the effect of smoking on these outcomes in the dialysis population is less well studied.
Systematic review and meta-analysis of cohort studies.
Setting & Population
Adults treated with long-term hemodialysis or peritoneal dialysis.
Selection Criteria for Included Studies
Cohort studies of unselected dialysis patients reporting the association between smoking status and cardiovascular morbidity and/or mortality.
Smoking status (determined by patient report).
1) All-cause or cardiovascular mortality; 2) Incident cardiovascular events
We identified 34 studies which fulfilled all inclusion criteria. Of these, 26 studies provide data on smoking and mortality and 10 (n = 6538) were included in a meta-analysis. The pooled hazard ratio for all-cause mortality in smokers compared to non-smokers was 1.65 (95% CI , 1.26–2.14; p<0.001) Eleven studies provided data on smoking and incident cardiovascular events, 5 (pooled n = 845) were included in a meta-analysis. The pooled hazard ratio for composite cardiovascular events in smokers compared to non-smokers was 1.01 (95% CI, 0.98–1.05, p 0.4)‥
Data for these meta-analyses were heterogeneous. Few individual studies assessed smoking as the primary variable of interest.
Active smoking is associated with a significant increase in all-cause mortality in dialysis patients, although there was not a corresponding increased risk of cardiovascular events.
The oral microbiome, the complex ecosystem of microbes inhabiting the human mouth, harbors several thousands of bacterial types. The proliferation of pathogenic bacteria within the mouth gives rise to periodontitis, an inflammatory disease known to also constitute a risk factor for cardiovascular disease. While much is known about individual species associated with pathogenesis, the system-level mechanisms underlying the transition from health to disease are still poorly understood. Through the sequencing of the 16S rRNA gene and of whole community DNA we provide a glimpse at the global genetic, metabolic, and ecological changes associated with periodontitis in 15 subgingival plaque samples, four from each of two periodontitis patients, and the remaining samples from three healthy individuals. We also demonstrate the power of whole-metagenome sequencing approaches in characterizing the genomes of key players in the oral microbiome, including an unculturable TM7 organism. We reveal the disease microbiome to be enriched in virulence factors, and adapted to a parasitic lifestyle that takes advantage of the disrupted host homeostasis. Furthermore, diseased samples share a common structure that was not found in completely healthy samples, suggesting that the disease state may occupy a narrow region within the space of possible configurations of the oral microbiome. Our pilot study demonstrates the power of high-throughput sequencing as a tool for understanding the role of the oral microbiome in periodontal disease. Despite a modest level of sequencing (∼2 lanes Illumina 76 bp PE) and high human DNA contamination (up to ∼90%) we were able to partially reconstruct several oral microbes and to preliminarily characterize some systems-level differences between the healthy and diseased oral microbiomes.
Isolates represent multiple genetic lineages, a finding consistent with multiple emergences from endemic reservoirs.
Numerous outbreaks of cholera have occurred in Kenya since 1971. To more fully understand the epidemiology of cholera in Kenya, we analyzed the genetic relationships among 170 Vibrio cholerae O1 isolates at 5 loci containing variable tandem repeats. The isolates were collected during January 2009–May 2010 from various geographic areas throughout the country. The isolates grouped genetically into 5 clonal complexes, each comprising a series of genotypes that differed by an allelic change at a single locus. No obvious correlation between the geographic locations of the isolates and their genotypes was observed. Nevertheless, geographic differentiation of the clonal complexes occurred. Our analyses showed that multiple genetic lineages of V. cholerae were simultaneously infecting persons in Kenya. This finding is consistent with the simultaneous emergence of multiple distinct genetic lineages of V. cholerae from endemic environmental reservoirs rather than recent introduction and spread by travelers.
phenotypes; genotypes; Vibrio cholerae; cholera; characterization; molecular epidemiology; outbreaks; bacteria; Kenya
In the title compound, C20H13ClN2O2S, the chlorophenyl, phenyl and thienoyl rings are oriented at dihedral angles 17.84 (7), 53.13 (8) and 34.03 (8)°, respectively, to the central pyrazole ring. An intramolecular O—H⋯O hydrogen bond occurs. In the crystal, pairs of bifurcated O—H⋯O hydrogen bonds link molecules into inversion dimers with R
2(12) graph-set motifs.
AIM: To investigate the effects of ESC-3 isolated from crocodile bile on the growth and apoptosis induction of human cholangiocarcinoma cells.
METHODS: ESC-3 was isolated from crocodile bile by Sephadex LH-20 and RP-18 reversed-phase column. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was conducted to determine the effects of ESC-3 on the proliferation of human cholangiocarcinoma cell lines (QBC939, Sk-ChA-1 and MZ-ChA-1). Giemsa staining, Hoechst 33258 and acridine orange/ethidium bromide staining showed the morphological changes of Mz-ChA-1 cells exposed to ESC-3 at different concentrations. Flow cytometry with regular propidium iodide (PI) staining was performed to analyze the cell cycle distribution of Mz-ChA-1 cells and to assess apoptosis by annexin v-fluorescein isothiocyanate (V-FITC)/PI staining. Rh123 staining was used to detect the alteration of mitochondrial membrane potential (ΔΨm). The protein levels of Bax, Bcl-2, Cdk2, cytochrome c and caspase-3 were further confirmed by Western blotting.
RESULTS: ESC-3 significantly inhibited the growth of three human cholangiocarcinoma cell lines and arrested Mz-ChA-1 cell cycle at G0/G1 phase. Mz-ChA-1 cells showed typical apoptotic morphological changes after treated with ESC-3 (10 μg/mL) for 48 h. Cell death assay indicated that Mz-ChA-1 cells underwent apoptosis in a dose-dependent manner induced by ESC-3. In addition, ESC-3 treatment could downregulate the protein level of Bcl-2 and upregulate the Bax, leading to the increase in the ratio of Bax to Bcl-2 in Mz-ChA-1 cells. Meanwhile, cytochrome c was released from the mitochondria into the cytosol, which subsequently initiated the activation of caspase-3. All these events were associated with the collapse of the mitochondrial membrane potential.
CONCLUSION: ESC-3, the active ingredient of crocodile bile, induced apoptosis in Mz-ChA-1 cells through the mitochondria-dependent pathway and may be a potential chemotherapeutic drug for the treatment of cholangiocarcinoma.
Crocodylus siamensis bile; Cholangiocarcinoma; Antiproliferation; Apoptosis; Mitochondria
The regenerative potential of injured adult tissue suggests the physiological existence of cells capable of participating in the reparative process. Recent studies indicate that stem-like cells residing in tissues contribute to tissue repair and are replenished by precursor bone marrow–derived cells. Mesenchymal stromal cells (MSC) are among the candidates for reparative cells. These cells can potentially be mobilized into the circulation in response to injury signals and exert their reparative effects at the site of injury. Current therapies for musculoskeletal injuries pose unavoidable risks which can impede full recovery. Trafficking of MSC to the injury site and their subsequent participation in the regenerative process is thought to be a natural healing response that can be imitated or augmented by enhancing the endogenous MSC pool with exogenously administered MSC. Therefore, a promising alternative to the existing strategies employed in the treatment of musculoskeletal injuries is to reinforce the inherent reparative capacity of the body by delivering MSC harvested from the patient’s own tissues to the site of injury. The aim of this review is to inform the reader of studies that have evaluated the intrinsic homing and regenerative abilities of MSC, with particular emphasis on the repair of musculoskeletal injuries. Research that supports the direct use of MSC (without in vitro differentiation into tissue-specific cells) will also be reported. Based on accruing evidence that the natural healing mechanism involves the recruitment of MSC and their subsequent reparative actions at the site of injury, as well as documented therapeutic response after the exogenous administration of MSC, the feasibility of the emerging strategy of instant stem-cell therapy will be proposed.
mesenchymal stromal cell; homing; trafficking; tissue engineering; bone; cartilage
Maternal consumption of fish during the gestational period exposes the fetus to both nutrients, especially the long-chain polyunsaturated fatty acids (LCPUFAs), believed to be beneficial for fetal brain development, as well as to the neurotoxicant methylmercury (MeHg). We recently reported that nutrients present in fish may modify MeHg neurotoxicity. Understanding the apparent interaction of MeHg exposure and nutrients present in fish is complicated by the limitations of modeling methods. In this study we fit varying coefficient function models to data from the Seychelles Child Development Nutrition Study (SCDNS) cohort to assess the association of dietary nutrients and children’s development. This cohort of mother-child pairs in the Republic of Seychelles had fish consumption averaging 9 meals per week. Maternal nutritional status was assessed for five different nutritional components known to be present in fish (n-3 LCPUFA, n-6 LCPUFA, iron status, iodine status, and choline) and associated with children’s neurological development. We also included prenatal MeHg exposure (measured in maternal hair). We examined two child neurodevelopmental outcomes (Bayley Scales Infant Development-II (BSID-II) Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI)), each administered at 9 and at 30 months. The varying coefficient models allow the possible interactions between each nutritional component and MeHg to be modeled as a smoothly varying function of MeHg as an effect modifier. Iron, iodine, choline, and n-6 LCPUFA had little or no observable modulation at different MeHg exposures. In contrast the n-3 LCPUFA docosahexaenoic acid (DHA) had beneficial effects on the BSID-II PDI that were reduced or absent at higher MeHg exposures. This study presents a useful modeling method that can be brought to bear on questions involving interactions between covariates, and illustrates the continuing importance of viewing fish consumption during pregnancy as a case of multiple exposures to nutrients and to MeHg. The results encourage more emphasis on a holistic view of the risks and benefits of fish consumption as it relates to infant development.
Varying-coefficient function models; mercury exposure; neurodevelopment; interaction between nutritional status and toxic exposure
Fruit wastes are one of the main sources of municipal waste. In order to explore the potential of fruit wastes as natural resources of bioactive compounds, the antioxidant potency and total phenolic contents (TPC) of lipophilic and hydrophilic components in wastes (peel and seed) of 50 fruits were systematically evaluated. The results showed that different fruit residues had diverse antioxidant potency and the variation was very large. Furthermore, the main bioactive compounds were identified and quantified, and catechin, cyanidin 3-glucoside, epicatechin, galangin, gallic acid, homogentisic acid, kaempferol, and chlorogenic acid were widely found in these residues. Especially, the values of ferric-reducing antioxidant power (FRAP), trolox equivalent antioxidant capacity (TEAC) and TPC in the residues were higher than in pulps. The results showed that fruit residues could be inexpensive and readily available resources of bioactive compounds for use in the food and pharmaceutical industries.
fruit residues; FRAP; TEAC; phenolic content
The purpose of this study was to identify dietary patterns among Korean elementary school girls based on the change in body mass index (BMI), body fat, bone mineral density (BMD), and bone mineral content (BMC) during 22 months and to explore the characteristics of dietary patterns identified. Girls aged 9-11 years were recruited and 3-day dietary data were collected four times. Subjects with a diet record of 8 or more days and anthropometric data measured at baseline and 22 months later were included (n = 198). Reduced rank regression was utilized to derive dietary patterns using a change in BMI, body fat, and calcaneus BMD and BMC as response variables. Two dietary patterns were identified: the "Egg and Rice" dietary pattern and "Fruit, Nuts, Milk Beverage, Egg, Grain" (FNMBEG) dietary pattern. Subjects who had high score on the FNMBEG pattern consumed various food groups, including fruits, nuts and seeds, and dairy products, whereas subjects in the "Egg and Rice" dietary pattern group did not. Both dietary patterns showed a positive association with change in BMI and body fat. However, subjects who had a higher score on the "Egg and Rice" dietary pattern had less of a BMC increase, whereas subjects who had a higher score on the FMBEG dietary pattern had more increased BMC over 22 months after adjusting for age, body and bone mass, and Tanner stage at baseline. Our results provide evidence that a well-balanced diet contributes to lean body mass growth among young girls.
Adolescent; physical growth; bone mass; dietary pattern; reduced rank regression
AIM: To assess the application of the Kasai procedure in the surgical management of hilar bile duct strictures.
METHODS: Ten consecutive patients between 2005 and 2011 with hilar bile duct strictures who underwent the Kasai procedure were retrospectively analyzed. Kasai portoenterostomy with the placement of biliary stents was performed in all patients. Clinical characteristics, postoperative complications, and long-term outcomes were analyzed. All patients were followed up for 2-60 mo postoperatively.
RESULTS: Patients were classified according to the Bismuth classification of biliary strictures. There were two Bismuth III and eight Bismuth IV lesions. Six lesions were benign and four were malignant. Of the benign lesions, three were due to post-cholecystectomy injury, one to trauma, one to inflammation, and one to inflammatory pseudotumor. Of the malignant lesions, four were due to hilar cholangiocarcinoma. All patients underwent Kasai portoenterostomy with the placement of biliary stents. There were no perioperative deaths. One patient experienced anastomotic leak and was managed conservatively. No other complications occurred perioperatively. During the follow-up period, all patients reported a good quality of life.
CONCLUSION: The Kasai procedure combined with biliary stents may be appropriate for patients with hilar biliary stricture that cannot be managed by standard surgical methods.
Kasai procedure; Hilar bile duct; Stricture; Surgery
Studies of neurodevelopmental outcomes in offspring exposed to MeHg from maternal consumption of fish have primarily measured cognitive abilities. Reported associations have been subtle and in both adverse and beneficial directions. Changes in functional outcomes such as school achievement and behavior in exposed children and adolescents have not been examined. We undertook an assessment of school success of children in the Seychelles Child Development Study (SCDS) Main Cohort to determine if there were any associations with either prenatal or recent postnatal MeHg exposure. The primary endpoints were Seychelles nationally standardized end-of-year examinations given when the cohort children were 9 and 17 years of age. A subgroup (n = 215) from the Main Cohort was also examined at 9 years of age using a regional achievement test called SACMEQ. Prenatal MeHg exposure was 6.8 ppm in maternal hair; recent postnatal exposure was 6.09 ppm at 9 years and 8.0 ppm at 17 years, measured in child hair. Multiple linear regression analyses showed no pattern of associations between prenatal or postnatal exposure, and either the 9- or 17-year end-of-year examination scores. For the subgroup of 215 subjects who participated in the SACMEQ test, there were significant adverse associations between examination scores and postnatal exposure, but only for males. The average postnatal exposure level in child hair for this subgroup was significantly higher than for the overall cohort. These results are consistent with our earlier studies and support the interpretation that prenatal MeHg exposure at dosages achieved by mothers consuming a diet high in fish are not associated with adverse educational measures of scholastic achievement. The adverse association of educational measures with postnatal exposure in males is intriguing, but will need to be confirmed by further studies examining factors that influence scholastic achievement.
Recent research has explored dual-task deficits during locomotion in older adults, yet the mechanisms underlying these deficits are poorly understood. In the current study, we examined one possible factor contributing to these deficits, the inability to flexibly allocate attention between two tasks.
Twelve healthy young adults and 12 healthy elderly adults performed obstacle avoidance while walking and an auditory Stroop task either alone or simultaneously.
Using an attentional allocation index (AAI) to compare performance of healthy young and older adults and to measure the flexibility of allocation of attention, results showed a tendency in older adults toward a decreased ability to flexibly allocate their attention between the two tasks, with small AAI values. The decreased ability to allocate attention in older adults was found to be more prominent in the auditory Stroop task performance than in the obstacle avoidance task.
This study suggests that an important factor contributing to decreased dual-task performance in older adults when simultaneously performing a postural and secondary cognitive task is a reduced ability to flexibly allocate attention between the two tasks, with the general ability to switch attention flexibly being predictive of the ability to adhere to a prioritized focus.
Gait; Attention; Aging
Recent research has begun to explore the ability of older adults to perform balance tasks while simultaneously performing a secondary cognitive task; however, it has suffered from limitations regarding the mechanisms underlying the problems that cause dual-task deficits in older adults with balance impairments. Two possible attentional mechanisms (reduced general attentional capacity vs. a true dual-task performance deficit and inability to allocate attention between two tasks) contributing to balance constraints were examined.
Twelve healthy elderly adults and 12 elderly adults with balance impairments (BIOA) were asked to perform obstacle avoidance while walking, either alone or simultaneously with an auditory Stroop. Two experiments were designed to examine attentional mechanisms that may contribute to reduce performance in the dual-task situations for the BIOA.
Experiment 1 determined whether for BIOA, single vs. dual-task performance conditions led to similar effects as a single-task difficulty (congruent vs. incongruent) manipulation. Results indicated that dual-task performance reduction did not exceed that of the difficult single task, suggesting that neither older adult group showed a true dual-task performance deficit, but rather BIOA showed a reduced attentional capacity. Experiment 2 showed that BIOA also showed deficits in flexibly focusing their attention between two tasks according to instructions.
Our study confirmed that the ability to allocate attention between a postural task and a secondary cognitive task was impaired in BIOA; it is suggested that inability to flexibly allocate attention could be one important factor among many factors that contribute to balance constraints during gait in fallers.
Aging; gait; attention