82 research outputs found

    Hong Kong Chinese parental attitudes towards vaccination and associated socio-demographic disparities

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    Background: Most previous studies on parental attitudes towards vaccination focused on a disease-specific vaccine. In this study we describe general attitudes towards vaccination in Chinese parents and associated socio-demographic disparities. Methods: Data were collected from a random sample of 1996 Hong Kong Chinese parents by telephone interviews (response rate 60%). Multiple linear regression analysis was performed. Results: Most parents believed vaccination to be effective (91.6%) and beneficial (78.7%), though many considered optional vaccines unimportant (39.5%) and unnecessary (62.1%). Demographic characteristics associated with parental negative attitudes to vaccination included being female, born in Hong Kong, married, having fewer children, and children ever experienced vaccination side effects. Lower personal income and religious affiliation were associated with more hesitant attitudes towards optional vaccines. Conclusion: Segments of the population hold significantly negative attitudes towards vaccination and optional vaccines, suggesting a need for targeted efforts on vaccination communication in these groups.postprin

    Divergent Biochemical Fractionation, Not Convergent Temperature, Explains Cellulose Oxygen Isotope Enrichment across Latitudes

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    Recent findings based on the oxygen isotope ratios of tree trunk cellulose indicate that the temperature of biomass production in biomes ranging from boreal to subtropical forests converge to an average leaf temperature of 21.4°C. The above conclusion has been drawn under the assumption that biochemically related isotopic fractionations during cellulose synthesis are not affected by temperature. Here we test the above assumption by heterotrophically generating cellulose at different temperatures and measuring the proportion of carbohydrate oxygen that exchange with water during cellulose synthesis and the average biochemical fractionation associated with this exchange. We observed no variation in the proportion of oxygen that exchange with different temperatures, which averaged 0.42 as it has been observed in other studies. On the other hand, the biochemical oxygen isotope fractionation during cellulose synthesis is affected by temperature and can be described by a 2nd order polynomial equation. The biochemical fractionation changes little between temperatures of 20 and 30°C averaging 26‰ but increases at lower temperatures to values of 31‰. This temperature sensitive biochemical fractionation explains the pattern of cellulose oxygen isotope ratios of aquatic plants encompassing several latitudes. The observed temperature sensitive biochemical fractionation also indicates that divergent biochemical fractionation and not convergent leaf temperature explains the increase in oxygen isotope enrichment of cellulose across several biomes

    Clinicoradiological manifestations of paraganglioma syndromes associated with succinyl dehydrogenase enzyme mutation

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    BACKGROUND: Paragangliomas are rare tumours derived from the autonomic nervous system that have increasingly been recognised to have a genetic predisposition. Mutations of the enzyme succinyl dehydrogenase (SDH) have proven to result in paraganglioma formation. There are four subunits (A through D) that form the enzyme complex and are associated with different genophenotypic expressions of disease. SDHB and SDHD mutations are more common, whereas SDHA and SDHC mutations are rare. Patients with SDHB mutations are prone to extra-adrenal pheochromocytomas, malignant disease and extra-paraganglial neoplasia, whereas SDHD mutations have a greater propensity for multiple, benign head and neck paragangliomas. METHODS: Diagnosis of a sporadic paraganglioma or pheochromocytoma should lead to a full genetic workup of the patient and family if SDH mutations are found. RESULTS: Further annual screening will be required depending on the mutation, which can have a significant impact on radiologists and the resources of the radiology department. CONCLUSION: We present our imaging experience with a series of patients with proven SDH mutations resulting in paragangliomas with a review of the literature

    Direct measurement of local oxygen concentration in the bone marrow of live animals

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    Characterizing how the microenvironment, or niche, regulates stem cell activity is central to understanding stem cell biology and to developing strategies for therapeutic manipulation of stem cells1. Low oxygen tension (hypoxia) is commonly thought to be a shared niche characteristic in maintaining quiescence in multiple stem cell types2–4. However, support for the existence of a hypoxic niche has largely come from indirect evidence such as proteomic analysis5, expression of HIF-1 and related genes6, and staining with surrogate hypoxic markers (e.g. pimonidazole)6–8. Here we perform direct in vivo measurements of local oxygen tension (pO2) in the bone marrow (BM) of live mice. Using two-photon phosphorescence lifetime microscopy (2PLM), we determined the absolute pO2 of the BM to be quite low (<32 mmHg) despite very high vascular density. We further uncovered heterogeneities in local pO2, with the lowest pO2 (~9.9 mmHg, or 1.3%) found in deeper peri-sinusoidal regions. The endosteal region, by contrast, is less hypoxic as it is perfused with small arteries that are often positive for the marker nestin. These pO2 values change dramatically after radiation and chemotherapy, pointing to the role of stress in altering the stem cell metabolic microenvironment

    Does the diurnal cycle of cortisol explain the relationship between physical performance and cognitive function in older adults?

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    Background Regular physical activity is a promising strategy to treat and prevent cognitive decline. The mechanisms that mediate these benefits are not fully clear but physical activity is thought to attenuate the harmful effects of chronic psychological stress and hypercortisolism on cognition. However, the circadian pattern of cortisol secretion is complex and it is not known which aspects are most closely associated with increased cognitive function and better physical performance. This is the first study to simultaneously measure cognitive function, the diurnal cycle of salivary cortisol and physical performance in older adults, without cognitive impairment (n = 30) and with amnestic Mild Cognitive Impairment (aMCI) (n = 30). Results Regression analysis showed that better cognitive function was associated with better physical performance. A greater variance in cortisol levels across the day from morning to evening was associated with better cognitive function and physical performance. Conclusions The results support the idea that a more dynamic cortisol secretion pattern is associated with better cognitive function and physical performance even in the presence of cognitive impairment, but our results could not confirm a mediating role in this relationship

    Novel genetic associations for blood pressure identified via gene-alcohol interaction in up to 570K individuals across multiple ancestries

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    Heavy alcohol consumption is an established risk factor for hypertension; the mechanism by which alcohol consumption impact blood pressure (BP) regulation remains unknown. We hypothesized that a genome-wide association study accounting for gene-alcohol consumption interaction for BP might identify additional BP loci and contribute to the understanding of alcohol-related BP regulation. We conducted a large two-stage investigation incorporating joint testing of main genetic effects and single nucleotide variant (SNV)-alcohol consumption interactions. In Stage 1, genome-wide discovery meta-analyses in approximate to 131 K individuals across several ancestry groups yielded 3,514 SNVs (245 loci) with suggestive evidence of association (P <1.0 x 10(-5)). In Stage 2, these SNVs were tested for independent external replication in individuals across multiple ancestries. We identified and replicated (at Bonferroni correction threshold) five novel BP loci (380 SNVs in 21 genes) and 49 previously reported BP loci (2,159 SNVs in 109 genes) in European ancestry, and in multi-ancestry meta-analyses (P < 5.0 x 10(-8)). For African ancestry samples, we detected 18 potentially novel BP loci (P< 5.0 x 10(-8)) in Stage 1 that warrant further replication. Additionally, correlated meta-analysis identified eight novel BP loci (11 genes). Several genes in these loci (e.g., PINX1, GATA4, BLK, FTO and GABBR2 have been previously reported to be associated with alcohol consumption. These findings provide insights into the role of alcohol consumption in the genetic architecture of hypertension

    oapital absorptive capacity in developing countries. Foreword by J.H. Adler;.

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