134 research outputs found
External costs of atmospheric Pb emissions: valuation of neurotoxic impacts due to inhalation
<p>Abstract</p> <p>Background</p> <p>The Impact Pathway Approach (IPA) is an innovative methodology to establish links between emissions, related impacts and monetary estimates. Only few attempts have so far been presented regarding emissions of metals; in this study the external costs of airborne lead (Pb) emissions are assessed using the IPA. Exposure to Pb is known to provoke impacts especially on children's cognition. As cognitive abilities (measured as IQ, intelligence quotient) are known to have implications for lifetime income, a pathway can be established leading from figures for Pb emissions to the implied loss in earnings, and on this basis damage costs per unit of Pb emission can be assessed.</p> <p>Methods</p> <p>Different types of models are here linked. It is relatively straightforward to establish the relationship between Pb emissions and consequent increase in air-Pb concentration, by means of a Gaussian plume dispersion model (OML). The exposed population can then be modelled by linking the OML-output to population data nested in geo-referenced grid cells. Less straightforward is to establish the relationship between exposure to air-Pb concentrations and the resulting blood-Pb concentration. Here an Age-Dependent Biokinetic Model (ADBM) for Pb is applied. On basis of previous research which established links between increases in blood-Pb concentrations during childhood and resulting IQ-loss we arrive at our results.</p> <p>Results</p> <p>External costs of Pb airborne emissions, even at low doses, in our site are in the range of 41-83 €/kg emitted Pb, depending on the considered meteorological year. This estimate applies only to the initial effects of air-Pb, as our study does not address the effects due to the Pb environmental-accumulation and to the subsequent Pb re-exposure. These are likely to be between one and two orders of magnitude higher.</p> <p>Conclusions</p> <p>Biokinetic modelling is a novel tool not previously included when applying the IPA to explore impacts of Pb emissions and related external costs; it allows for more fine-tuned, age-dependent figures for the external costs from low-dose exposure. Valuation of additional health effects and impacts e.g. due to exposure via ingestion appear to be feasible when extending the insights from the present pilot study.</p
Transforming growth factor beta-1 (TGFB1) and peak bone mass: association between intragenic polymorphisms and quantitative ultrasound of the heel
BACKGROUND: Variance of peak bone mass has a substantial genetic component, as has been shown with twin studies examining quantitative measures such as bone mineral density (BMD) and quantitative ultrasound (QUS). Evidence implicating single nucleotide polymorphisms (SNPs) of the transforming growth factor beta-1 (TGFB1) gene is steadily accumulating. However, a comprehensive look at multiple SNPs at this locus for their association with indices of peak bone mass has not been reported. METHODS: A cohort of 653 healthy Caucasian females 18 to 35 years old was genotyped for seven TGFB1 SNPs. Polymorphisms were detected by restriction endonuclease digestion of amplified DNA segments. RESULTS: The frequencies of the least common allele at G-800A, C-509T, codon 10 (L10P), codon 25 (R25P), codon 263 (T263I), C861-20T, and 713-8 delC loci were 0.07, 0.33, 0.41, 0.08, 0.04, 0.25 and 0.01, respectively. A significant association was seen between QUS Stiffness Index (QUS-SI) and the SNP at codon 10 and the linked promoter SNP, C-509T. This association remained significant after multiple regression was used to incorporate important clinical covariates – age, BMI, level of activity, family history, and caffeine intake – into the model. CONCLUSION: The association of QUS-SI with -509T is consistent with a gene-dose effect, while only individuals homozygous for the codon 10P allele showed a significant increase. In this cohort of young healthy Caucasian females, the T allele at position -509 is associated with greater bone mass as measured by calcaneal ultrasound
The effect of five years versus two years of specialised assertive intervention for first episode psychosis - OPUS II: study protocol for a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>The Danish OPUS I trial randomized 547 patients with first-episode psychosis to a two-year early-specialised assertive treatment programme (OPUS) versus standard treatment. The two years OPUS treatment had significant positive effects on psychotic and negative symptoms, secondary substance abuse, treatment adherence, lower dosage of antipsychotic medication, and a higher treatment satisfaction. However, three years after end of the OPUS treatment, the positive clinical effects were not sustained, except that OPUS-treated patients were significantly less likely to be institutionalised compared with standard-treated patients. The major objective of the OPUS II trial is to evaluate the effects of five years of OPUS treatment versus two years of OPUS treatment.</p> <p>Methods</p> <p>The OPUS II trial is designed as a randomized, open label, parallel group trial with blinded outcome assessment. Based on our sample size estimation, 400 patients treated in OPUS for two years will be randomized to further three years of OPUS treatment versus standard treatment. The specialized assertive OPUS treatment consists of three core elements: assertive community treatment, psycho-educational family treatment, and social skills training.</p> <p>Discussion</p> <p>It has been hypothesized that there is a critical period from onset up to five years, which represents a window of opportunity where a long-term course can be influenced. Extending the specialized assertive OPUS treatment up to five years may allow the beneficial effects to continue beyond the high-risk period, through consolidation of improved social and functional outcome.</p> <p>Trial registration</p> <p>Clinical Trial.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00914238">NCT00914238</a></p
The -1997 G/T and Sp1 Polymorphisms in the Collagen Type I alpha1 (COLIA1) Gene in Relation to Changes in Femoral Neck Bone Mineral Density and the Risk of Fracture in the Elderly: The Rotterdam Study
The COLIA1 Sp1 polymorphism has been associated with bone mineral density (BMD) and fracture. A promoter polymorphism, -1997 G/T, also has been associated with BMD. In this study, we examined whether these polymorphisms alone and in the form of haplotypes influence bone parameters and fracture risk in a large population-based cohort of elderly Caucasians. We determined the COLIA1 -1997 G/T (promoter) and Sp1 G/T (intron) polymorphisms in 6,280 individuals and inferred haplotypes. Femoral neck BMD and BMD change were compared across COLIA1 genotypes at baseline and follow-up (mean 6.5 years). We also investigated the relationship between the COLIA1 polymorphisms and incident nonvertebral fractures, which were recorded during a mean follow-up period of 7.4 years. Vertebral fractures were assessed by radiographs on 3,456 genotyped individuals. Femoral neck BMD measured at baseline was 3.8% lower in women carrying two copies of the T-Sp1 allele (P for trend = 0.03). No genotype dependent differences in BMD loss were observed. In women homozygous for the T allele of the Sp1 polymorphism, the risk of fragility fracture increased 2.3 times (95% confidence interval 1.4–3.9, P = 0.001). No such association was observed with the promoter polymorphism. In men, no association with either the Sp1 or the -1997 G/T promoter polymorphism was seen with BMD or fracture. High linkage disequilibrium (LD; D′ = 0.99, r2 = 0.03) exists between the two studied polymorphisms. We observed three haplotypes in our population: haplotype 1 (Gpromoter–Gintron) frequency (f) = 69%, haplotype 2 (Gpromoter–Tintron) f = 17.6%, and haplotype 3 (Tpromoter–Gintron) f = 13.4%. Haplotype 2 was associated with a 2.1-fold increased risk of fragility fracture in women (95% confidence interval 1.2–3.7, P = 0.001). We confirm that the COLIA1 Sp1 polymorphism influences BMD and the risk of fracture in postmenopausal Caucasian women. In contrast, we found no independent effect of the -1997 G/T promoter polymorphism on BMD or fracture
Association between a variation in the phosphodiesterase 4D gene and bone mineral density
BACKGROUND: Fragility fractures caused by osteoporosis are a major cause of morbidity and mortality in aging populations. Bone mineral density (BMD) is a useful surrogate marker for risk of fracture and is a highly heritable trait. The genetic variants underlying this genetic contribution are largely unknown. METHODS: We performed a large-scale association study investigating more than 25,000 single nucleotide polymorphisms (SNPs) located within 16,000 genes. Allele frequencies were estimated in contrasting DNA pools from white females selected for low (<0.87 g/cm(2), n = 319) and high (> 1.11 g/cm(2), n = 321) BMD at the lumbar spine. Significant findings were verified in two additional sample collections. RESULTS: Based on allele frequency differences between DNA pools and subsequent individual genotyping, one of the candidate loci indicated was the phosphodiesterase 4D (PDE4D) gene region on chromosome 5q12. We subsequently tested the marker SNP, rs1498608, in a second sample of 138 white females with low (<0.91 g/cm(2)) and 138 females with high (>1.04 g/cm(2)) lumbar spine BMD. Odds ratios were 1.5 (P = 0.035) in the original sample and 2.1 (P = 0.018) in the replication sample. Association fine mapping with 80 SNPs located within 50 kilobases of the marker SNP identified a 20 kilobase region of association containing exon 6 of PDE4D. In a second, family-based replication sample with a preponderance of females with low BMD, rs1498608 showed an opposite relationship with BMD at different sites (p = 0.00044-0.09). We also replicated the previously reported association of the Ser37Ala polymorphism in BMP2, known to interact biologically with PDE4D, with BMD. CONCLUSION: This study indicates that variants in the gene encoding PDE4D account for some of the genetic contribution to bone mineral density variation in humans. The contrasting results from different samples indicate that the effect may be context-dependent. PDE4 inhibitors have been shown to increase bone mass in normal and osteopenic mice, but up until now there have been no reports implicating any member of the PDE4 gene family in human osteoporosis
Validation of the western ontario rotator cuff index in patients with arthroscopic rotator cuff repair: A study protocol
<p>Abstract</p> <p>Background</p> <p>Arthroscopic rotator cuff repair is described as being a successful procedure. These results are often derived from clinical general shoulder examinations, which are then classified as 'excellent', 'good', 'fair' or 'poor'. However, the cut-off points for these classifications vary and sometimes modified scores are used.</p> <p>Arthroscopic rotator cuff repair is performed to improve quality of life. Therefore, disease specific health-related quality of life patient-administered questionnaires are needed. The WORC is a quality of life questionnaire designed for patients with disorders of the rotator cuff. The score is validated for rotator cuff disease, but not for rotator cuff repair specifically.</p> <p>The aim of this study is to investigate reliability, validity and responsiveness of WORC in patients undergoing arthroscopic rotator cuff repair.</p> <p>Methods/Design</p> <p>An approved translation of the WORC into Dutch is used. In this prospective study three groups of patients are used: 1. Arthroscopic rotator cuff repair; 2. Disorders of the rotator cuff without rupture; 3. Shoulder instability.</p> <p>The WORC, SF-36 and the Constant Score are obtained twice before therapy is started to measure reliability and validity. Responsiveness is tested by obtaining the same tests after therapy.</p
Is Malaysia’s banded langur, Presbytis femoralis femoralis, actually Presbytis neglectus neglectus? Taxonomic revision with new insights on the radiation history of the Presbytis species group in Southeast Asia
The disjunct distribution of Presbytis femoralis subspecies across Sumatra (P. f. percura), southern (P. f. femoralis) and northern (P. f. robinsoni) Peninsular Malaysia marks the unique vicariance events in the Sunda Shelf. However, the taxonomic positions and evolutionary history of P. f. femoralis are unresolved after decades of research. To elucidate this evolutionary history, we analyzed 501 base pairs of the mitochondrial HVSI gene from 25 individuals representing Malaysia’s banded langur, with the addition of 29 sequences of Asian Presbytis from Genbank. Our results revealed closer affinity of P. f. femoralis to P. m. mitrata and P. m. sumatrana while maintaining the monophyletic state of P. f. femoralis as compared to P. f. robinsoni. Two central theses were inferred from the results; (1) P. f. femoralis does not belong in the same species classification as P. f. robinsoni, and (2) P. f. femoralis is the basal lineage of the Presbytis in Peninsular Malaysia. Proving the first hypothesis through genetic analysis, we reassigned P. f. femoralis of Malaysia to Presbytis neglectus (Schlegel’s banded langur) (Schlegel in Revue Methodique, Museum d’Histoire Naturelle des Pays-Bas 7:1, 1876) following the International Code of Zoological Nomenclature (article 23.3). The ancestors of P. neglectus are hypothesized to have reached southern Peninsular Malaysia during the Pleistocene and survived in refugium along the western coast. Consequently, they radiated upward, forming P. f. robinsoni and P. siamensis resulting in the highly allopatric distribution in Peninsular Malaysia. This study has successfully resolved the taxonomic position of P. neglectus in Peninsular Malaysia while providing an alternative biogeographic theory for the Asian Presbytis
HIF-1 Modulates Dietary Restriction-Mediated Lifespan Extension via IRE-1 in Caenorhabditis elegans
Dietary restriction (DR) extends lifespan in various species and also slows the onset of age-related diseases. Previous studies from flies and yeast have demonstrated that the target of rapamycin (TOR) pathway is essential for longevity phenotypes resulting from DR. TOR is a conserved protein kinase that regulates growth and metabolism in response to nutrients and growth factors. While some of the downstream targets of TOR have been implicated in regulating lifespan, it is still unclear whether additional targets of this pathway also modulate lifespan. It has been shown that the hypoxia inducible factor-1 (HIF-1) is one of the targets of the TOR pathway in mammalian cells. HIF-1 is a transcription factor complex that plays key roles in oxygen homeostasis, tumor formation, glucose metabolism, cell survival, and inflammatory response. Here, we describe a novel role for HIF-1 in modulating lifespan extension by DR in Caenorhabditis elegans. We find that HIF-1 deficiency results in extended lifespan, which overlaps with that by inhibition of the RSKS-1/S6 kinase, a key component of the TOR pathway. Using a modified DR method based on variation of bacterial food concentrations on solid agar plates, we find that HIF-1 modulates longevity in a nutrient-dependent manner. The hif-1 loss-of-function mutant extends lifespan under rich nutrient conditions but fails to show lifespan extension under DR. Conversely, a mutation in egl-9, which increases HIF-1 activity, diminishes the lifespan extension under DR. This deficiency is rescued by tissue-specific expression of egl-9 in specific neurons and muscles. Increased lifespan by hif-1 or DR is dependent on the endoplasmic reticulum (ER) stress regulator inositol-requiring protein-1 (IRE-1) and is associated with lower levels of ER stress. Therefore, our results demonstrate a tissue-specific role for HIF-1 in the lifespan extension by DR involving the IRE-1 ER stress pathway
Using wireless technology in clinical practice: does feedback of daily walking activity improve walking outcomes of individuals receiving rehabilitation post-stroke? Study protocol for a randomized controlled trial
The effect of an interactive cycling training on cognitive functioning in older adults with mild dementia: study protocol for a randomized controlled trial
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