Fluoride exposure and reported learning disability diagnosis among Canadian children: Implications for community water fluoridation.

OBJECTIVES: Recent studies have connected increased fluoride exposure with increased risk of neurodevelopmental-related outcomes, such as ADHD (attention deficit hyperactivity disorder) and lower IQ in children. Our primary objective was to examine the association between fluoride exposure and reported diagnosis of a learning disability among a population-based sample of Canadian children aged 3-12 years. METHODS: We analyzed data from Cycles 2 and 3 of the Canadian Health Measures Survey. Four measures of fluoride exposure were available: 1) urinary fluoride (µmol/L), 2) creatinine-adjusted urinary fluoride (µmol/mmol), 3) specific gravity-adjusted urinary fluoride (µmol/L), and 4) fluoride concentration of tap water (mg/L) (Cycle 3 only). Diagnosis of a learning disability (yes/no) was based on parental- or self-report. Associations were examined using logistic regression (where possible), unadjusted and adjusted for covariates. RESULTS: When Cycles 2 and 3 were examined separately, reported learning disability diagnosis was not significantly associated with any measure of fluoride exposure in unadjusted or adjusted models. When Cycles 2 and 3 were combined, a small but statistically significant effect was observed such that children with higher urinary fluoride had higher odds of having a reported learning disability in the adjusted model (p = 0.03). However, the association was not observed in models that used creatinine-adjusted urinary fluoride and specific gravity-adjusted urinary fluoride, which are believed to be more accurate measures due to their correction for urinary dilution. CONCLUSION: Overall, there did not appear to be a robust association between fluoride exposure and parental- or self-reported diagnosis of a learning disability among Canadian children.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

BACKGROUND: There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. METHODS: We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. RESULTS: There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. CONCLUSION: These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist.

Phylogeny and Haplotype Analysis of Fungi Within the Fusarium incarnatum-equiseti Species Complex.

Fusarium spp. are ranked among the top 10 most economically and scientifically important plant-pathogenic fungi in the world and are associated with plant diseases that include fruit decay of a number of crops. Fusarium isolates infecting bell pepper in Trinidad were identified based on sequence comparisons of the translation elongation factor gene (EF-1a) with sequences of Fusarium incarnatum-equiseti species complex (FIESC) verified in the FUSARIUM-ID database. Eighty-two isolates were identified as belonging to one of four phylogenetic species within the subclades FIESC-1, FIESC-15, FIESC-16, and FIESC-26, with the majority of isolates belonging to FIESC-15. A comparison of the level of DNA polymorphism and phylogenetic inference for sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) and EF-1a sequences for Trinidad and FUSARIUM-ID type species was carried out. The ITS sequences were less informative, had lower haplotype diversity and restricted haplotype distribution, and resulted in poor resolution and taxa placement in the consensus maximum-likelihood tree. EF-1a sequences enabled strongly supported phylogenetic inference with highly resolved branching patterns of the 30 phylogenetic species within the FIESC and placement of representative Trinidad isolates. Therefore, global phylogeny was inferred from EF-1a sequences representing 11 countries, and separation into distinct Incarnatum and Equiseti clades was again evident. In total, 42 haplotypes were identified: 12 were shared and the remaining were unique haplotypes. The most diverse haplotype was represented by sequences from China, Indonesia, Malaysia, and Trinidad and consisted exclusively of F. incarnatum isolates. Spain had the highest haplotype diversity, perhaps because both F. equiseti and F. incarnatum sequences were represented; followed by the United States, which contributed both F. equiseti and F. incarnatum sequences to the data set; then by countries representing Southeast Asia (China, Indonesia, Malaysia, Thailand, and Philippines) and Trinidad; both of these regions were represented by only F. incarnatum sequences. Trinidad shared two haplotypes with China and one haplotype with the United States for only F. incarnatum isolates. The findings of this study are important for devising disease management strategies and for understanding the phylogenetic relationships among members of the FIESC.

Unusual Legionnaires' outbreak in cool, dry Western Canada: an investigation using genomic epidemiology.

An outbreak of Legionnaires' disease occurred in an inner city district in Calgary, Canada. This outbreak spanned a 3-week period in November-December 2012, and a total of eight cases were identified. Four of these cases were critically ill requiring intensive care admission but there was no associated mortality. All cases tested positive for Legionella pneumophila serogroup 1 (LP1) by urinary antigen testing. Five of the eight patients were culture positive for LP1 from respiratory specimens. These isolates were further identified as Knoxville monoclonal subtype and sequence subtype ST222. Whole-genome sequencing revealed that the isolates differed by no more than a single vertically acquired single nucleotide variant, supporting a single point-source outbreak. Hypothesis-based environmental investigation and sampling was conducted; however, a definitive source was not identified. Geomapping of case movements within the affected urban sector revealed a 1·0 km common area of potential exposure, which coincided with multiple active construction sites that used water spray to minimize transient dust. This community point-source Legionnaires' disease outbreak is unique due to its ST222 subtype and occurrence in a relatively dry and cold weather setting in Western Canada. This report suggests community outbreaks of Legionella should not be overlooked as a possibility during late autumn and winter months in the Northern Hemisphere.

Detection and Molecular Characterization of Benzimidazole Resistance Among Colletotrichum truncatum Isolates Infecting Bell Pepper in Trinidad.

Anthracnose is an economically important disease that affects pepper (Capsicum spp.) production worldwide. Eighty-seven Colletotrichum truncatum isolates infecting bell pepper in Trinidad were isolated and screened for resistance to benomyl. All isolates were found to be highly resistant at the discriminatory dose of 10.0 µg/ml. The effective concentration required to achieve 50% colony growth inhibition values were found to be significantly higher (P ≤ 0.05) for isolates collected in South Trinidad compared with those collected in North Trinidad. Isolates with the resistant phenotype had a single amino acid substitution from glutamic acid to alanine at position 198 (E198A) within the ß-tubulin 2 gene. Single-nucleotide polymorphisms that result in amino acid substitutions in the ß-tubulin 2 protein are associated with high resistance to benzimidazole chemistries. There were also two other deduced amino acid changes at nucleotide positions 359 to 361 (ATA/TTG [F270Y]) and at 362 to 364 (CGC/GCC [A271S]). Genetic analysis revealed that benomyl-sensitive isolates clustered separately from the resistant isolates regardless of species, with strong bootstrap support (85%). Within the resistance cluster, there was an apparent differentiation among those isolates with the F200Y, E198A, and E198K genotypes, with moderate support (>60%) for clustering of the F200Y and E198K genotypes. C. truncatum clustered separately (97%) from the other resistant genotypes due to the additional amino acid substitutions detected. The findings also indicated that consistent benzimidazole fungicide use may explain the predominance of the C. truncatum pathogen populations in bell pepper fields in Trinidad because sensitive C. gloeosporioides sensu lato isolates were selectively minimized. This underlines the importance of accurate identification of Colletotrichum spp. associated with anthracnose disease and routine monitoring for development of fungicide resistance.

A meta-analysis to derive literature-based benchmarks for readmission and hospital mortality after patient discharge from intensive care.

INTRODUCTION: We sought to derive literature-based summary estimates of readmission to the ICU and hospital mortality among patients discharged alive from the ICU. METHODS: We searched MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials from inception to March 2013, as well as the reference lists in the publications of the included studies. We selected cohort studies of ICU discharge prognostic factors that in which readmission to the ICU or hospital mortality among patients discharged alive from the ICU was reported. Two reviewers independently abstracted the number of patients readmitted to the ICU and hospital deaths among patients discharged alive from the ICU. Fixed effects and random effects models were used to estimate the pooled cumulative incidence of ICU readmission and the pooled cumulative incidence of hospital mortality. RESULTS: The analysis included 58 studies (n = 2,073,170 patients). The majority of studies followed patients until hospital discharge (n = 46 studies) and reported readmission to the ICU (n = 46 studies) or hospital mortality (n = 49 studies). The cumulative incidence of ICU readmission was 4.0 readmissions (95% confidence interval (CI), 3.9 to 4.0) per 100 patient discharges using fixed effects pooling and 6.3 readmissions (95% CI, 5.6 to 6.9) per 100 patient discharges using random effects pooling. The cumulative incidence of hospital mortality was 3.3 deaths (95% CI, 3.3 to 3.3) per 100 patient discharges using fixed effects pooling and 6.8 deaths (95% CI, 6.1 to 7.6) per 100 patient discharges using random effects pooling. There was significant heterogeneity for the pooled estimates, which was partially explained by patient, institution and study methodological characteristics. CONCLUSIONS: Using current literature estimates, for every 100 patients discharged alive from the ICU, between 4 and 6 patients on average will be readmitted to the ICU and between 3 and 7 patients on average will die prior to hospital discharge. These estimates can inform the selection of benchmarks for quality metrics of transitions of patient care between the ICU and the hospital ward.

A systematic review of tools for predicting severe adverse events following patient discharge from intensive care units.

INTRODUCTION: The discharge of patients from the intensive care unit (ICU) to a hospital ward is a common transition of care that is associated with error and adverse events. Risk stratification tools may help identify high-risk patients for targeted interventions, but it is unclear if proper tools have been developed. METHODS: We searched Ovid EMBASE, Ovid MEDLINE, CINAHL, PUBMED and Cochrane Central Register of Controlled Trials from the earliest available date through March 2013, plus reference lists and citations of all studies included in the systematic review. Cohort studies were selected that described the derivation, validation or clinical impact of tools for predicting medical emergency team activation, ICU readmission or mortality following patient discharge from the ICU. Data were extracted on the study design, setting, population, sample size, tool (components, measurement properties) and outcomes. RESULTS: The literature search identified 9,926 citations, of which eight studies describing eight tools met the inclusion criteria. Reported outcomes included ICU readmission (n=4 studies), hospital mortality (n=3 studies) and both ICU readmission and hospital mortality (n=1 studies). Seven of the tools were comprised of distinct measurable component variables, while one tool used subjective scoring of patient risk by intensive care physicians. The areas under receiver operator curves were reported for all studies and ranged from 0.66 to 0.92. A single study provided a direct comparative analysis between two tools. We did not find any studies evaluating the impact of risk prediction on processes and outcomes of care. CONCLUSIONS: Eight risk stratification tools for predicting severe adverse events following patient discharge from ICU have been developed, but have undergone limited comparative evaluation. Although risk stratification tools may help clinician decision-making, further evaluation of the existing tools' effects on care is required prior to clinical implementation.

Spatial distributions of the red palm mite, Raoiella indica (Acari: Tenuipalpidae) on coconut and their implications for development of efficient sampling plans.

The red palm mite (Raoiella indica), an invasive pest of coconut, entered the Western hemisphere in 2004, then rapidly spread through the Caribbean and into Florida, USA. Developing effective sampling methods may aid in the timely detection of the pest in a new area. Studies were conducted to provide and compare intra tree spatial distribution of red palm mite populations on coconut in two different geographical areas, Trinidad and Puerto Rico, recently invaded by the mite. The middle stratum of a palm hosted significantly more mites than fronds from the upper or lower canopy and fronds from the lower stratum, on average, had significantly fewer mites than the two other strata. The mite populations did not vary within a frond. Mite densities on the top section of the pinna had significantly lower mite densities than the two other sections, which were not significantly different from each other. In order to improve future sampling plans for the red palm mite, the data was used to estimate the variance components associated with the various levels of the hierarchical sampling design. Additionally, presence-absence data were used to investigate the probability of no mites being present in a pinna section randomly chosen from a frond inhabited by mites at a certain density. Our results show that the most precise density estimate at the plantation level is to sample one pinna section per tree from as many trees as possible.

Crop improvement for human nutrition: the case of the Mexican yam bean [abstract]

The Mexican yam bean (Pachyrhizus erosus) is a tuberous legume native to Central America. This species shows great potential for development as a food crop, to increase the existing limited base of staples that make up the diet in tropical regions, producing both protein rich grain and starch producing tubers. Starch quality is good due to its high digestibility. The major limitation to its use as a staple crop, however, is the low starch content of the tubers. The low variability of the existing gene pool for the genus limits the use of conventional plant breeding for improvement of the crop. Genetic engineering for crop improvement is, therefore adopted. The molecular genetics of carbohydrate metabolism in tubers of the Mexican yam bean is being studied. The result of such studies will guide the application of genetic engineering technology to improve starch content of the tubers. The work reported here describes the cloning of putative genes for the large subunit of ADP-glucose pyrophosphorylase (Agp2) from yam bean tubers. A cDNA library was constructed from RNA isolated from two-month-old yam bean tubers. A probe for Agp2 was prepared by RTPCR analysis of the tuber RNA preparations, using degenerate primers. Four clones, which hybridized to the probe, were isolated for further characterization. (AU)

Adenosine diphosphate glucose pyrophosphorylase genes in wheat: differential expression and gene mapping.

A full-length cDNA clone representing the large (shrunken-2) subunit of ADP-glucose pyrophosphorylase (AGP; EC 2.7.7.27) has been isolated from a cDNA library prepared from developing grain of hexaploid wheat (Triticum aestivum L., cv. Chinese Spring). The 2084-bp cDNA insert contains an open reading frame of 1566 nucleotides and primer-extension analysis indicated that the 5' end is 10 nucleotides shorter than the mRNA. The deduced protein contains 522 amino acids (57.8 kDa) and includes a putative transit peptide of 62 amino acids (6.5 kDa). The similarity of the deduced protein to the small subunit of AGP and to other AGP genes from plants and microorganisms is discussed. Northern hybridisation shows that the Agp1 genes (encoding the small subunit in the wheat endosperm) and the Agp2 genes (encoding the large subunit in the wheat endosperm) are differentially expressed in the wheat grain. Transcripts from both gene sets accumulate to high levels in the endosperm during grain development with the majority of the expression in the endopsperm rather than the embryo and pericarp layers. Although enzyme activity is detected in developing grains prior to 10 d post anthesis, only the Agp1 genes are active at this time (the Agp2 genes are not expressed until 10 d post anthesis). The possibility that the enzyme expressed during early grain development is a homotetramer of small subunits is discussed. The Agp1 and Agp2 genes are arranged as triplicate sets of single-copy homoeoloci in wheat. The Agp2 genes are located on the long arms of chromosomes 1A, 1B and 1D, about 80 cM from the centromere. The Agp1 genes have been mapped to a position just distal to the centromere on the long arms of chromosomes 7A, 7B and 7D.

Genetic differentiation of cocoa (Theobroma cacao L.) populations revealed by RAPD analysis.

In order to preserve and exploit the valuable genetic resources of tropical forest trees, such as cocoa, a systematic assessment of the available genetic variability is necessary. The approach we have used is based on a simple mini-prep DNA extraction procedure together with a polymerase-chain-reaction- (PCR)-based polymorphic assay procedure (RAPD). Twenty-five cocoa accessions: IMCs and PAs collected from Peru and LCTEENs collected from Ecuador, which are difficult to distinguish using morphological or biochemical descriptors, were uniquely fingerprinted using a minimum of three oligonucleotide primers. Analysis of the variability detected using RAPDs clearly discriminated between the geographical origin of the three cocoa populations. Partitioning of variability into within and between population components revealed that most variation was detected within a population. The potential of RAPD analysis to facilitate the rationalization of field gene banks and provide accurate estimates of diversity to allow optimization of collecting strategies is discussed.