| 1. |
- Decker, Ralph, 1968, et al.
(författare)
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Different thresholds of tissue-specific dose-responses to growth hormone in short prepubertal children
- 2012
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Ingår i: BMC Endocrine Disorders. - : Springer Science and Business Media LLC. - 1472-6823. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Background In addition to stimulating linear growth in children, growth hormone (GH) influences metabolism and body composition. These effects should be considered when individualizing GH treatment as dose-dependent changes in metabolic markers have been reported. Hypothesis: There are different dose-dependent thresholds for metabolic effects in response to GH treatment. Method A randomized, prospective, multicentre trial TRN 98-0198-003 was performed for a 2-year catch-up growth period, with two treatment regimens (a) individualized GH dose including six different dose groups ranging from 17--100 mug/kg/day (n=87) and (b) fixed GH dose of 43 mug/kg/day (n=41). The individualized GH dose group was used for finding dose--response effects, where the effective GH dose (ED 50%) required to achieve 50% Delta effect was calculated with piecewise linear regressions. Results Different thresholds for the GH dose were found for the metabolic effects. The GH dose to achieve half of a given effect (ED 50%, with 90% confidence interval) was calculated as 33(+/-24.4) mug/kg/day for [increment] left ventricular diastolic diameter (cm), 39(+/-24.5) mug/kg/day for [increment] alkaline phosphatase (mukat/L), 47(+/-43.5) mug/kg/day for [increment] lean soft tissue (SDS), 48(+/-35.7) mug/kg/day for [increment] insulin (mU/L), 51(+/-47.6) mug/kg/day for [increment] height (SDS), and 57(+/-52.7) mug/kg/day for [increment] insulin-like growth factor I (IGF-I) SDS. Even though lipolysis was seen in all subjects, there was no dose--response effect for Delta fat mass (SDS) or Delta leptin ng/ml in the dose range studied. None of the metabolic effects presented here were related to the dose selection procedure in the trial. Conclusions Dose-dependent thresholds were observed for different GH effects, with cardiac tissue being the most responsive and level of IGF-I the least responsive. The level of insulin was more responsive than that of IGF-I, with the threshold effect for height in the interval between.
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| 2. |
- Leblond, Claire S, et al.
(författare)
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Genetic and functional analyses of SHANK2 mutations suggest a multiple hit model of autism spectrum disorders.
- 2012
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n=396 patients and n=659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P=0.004, OR=2.37, 95% CI=1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P=0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the "multiple hit model" for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD.
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| 3. |
- Nygren, Andreas, 1967, et al.
(författare)
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Norepinephrine causes a pressure-dependent plasma volume decrease in clinical vasodilatory shock.
- 2010
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 54:7, s. 814-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent experimental studies have shown that a norepinephrine-induced increase in blood pressure induces a loss of plasma volume, particularly under increased microvascular permeability. We studied the effects of norepinephrine-induced variations in the mean arterial pressure (MAP) on plasma volume changes and systemic haemodynamics in patients with vasodilatory shock. METHODS: Twenty-one mechanically ventilated patients who required norepinephrine to maintain MAP > or =70 mmHg because of septic/postcardiotomy vasodilatory shock were included. The norepinephrine dose was randomly titrated to target MAPs of 60, 75 and 90 mmHg. At each target MAP, data on systemic haemodynamics, haematocrit, arterial and mixed venous oxygen content and urine flow urine were measured. Changes in the plasma volume were calculated as 100 x (Hct(pre)/Hct(post)-1)/ (1-Hct(pre)), where Hct(pre) and Hct(post) are haematocrits before and after intervention. RESULTS: Norepinephrine doses to obtain target MAPs of 60, 75 and 90 mmHg were 0.20+/-0.18, 0.29+/-0.18 and 0.42+/-0.31 microg/kg/min, respectively. From 60 to 90 mmHg, increases in the cardiac index (15%), systemic oxygen delivery index (25%), central venous pressure (CVP) (20%) and pulmonary artery occlusion pressure (33%) were seen, while the intrapulmonary shunt fraction was unaffected by norepinehrine. Plasma volume decreased by 6.5% and 9.4% (P<0.0001) when blood pressure was increased from 60 to 75 and 90 mmHg, respectively. MAP (P<0.02) independently predicted the decrease in plasma volume with norepinephrine but not CVP (P=0.19), cardiac index (P=0.73), norepinephrine dose (P=0.58) or urine flow (P=0.64). CONCLUSIONS: Norepinephrine causes a pressure-dependent decrease in the plasma volume in patients with vasodilatory shock most likely caused by transcapillary fluid extravasation.
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| 4. |
- Nygren, Kristiina, et al.
(författare)
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A comprehensive phylogeny of Neurospora reveals a link between reproductive mode and molecular evolution in fungi
- 2011
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 59:3, s. 649-663
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous ascomycete genus Neurospora encompasses taxa with a wide range of reproductive modes. Sexual reproduction in this genus can be divided into three major modes; heterothallism (self-incompatibility), homothallism (self-compatibility) and pseudohomothallism (partial self-compatibility). In addition to the sexual pathway, most of the heterothallic taxa propagate with morphologically distinct, vegetative dissemination propagules (macroconidia), while this feature is undetected in the majority of the homothallic taxa. In this study, we used sequence information of seven nuclear gene loci from 43 taxa (295 of the possible 301 locus-by-taxon combinations) to create a phylogeny of Neurospora. The results suggest that transitions in reproductive mode have occurred at multiple times within this group of fungi. Although a homothallic ancestor would imply fewer switches in reproductive mode, we argue that the ancestor of Neurospora was likely heterothallic and that homothallism has evolved independently at least six times in the evolutionary history of the genus. Furthermore, the two pseudohomothallic taxa of Neurospora (N. tetrasperma and N. tetraspora) represent two independent origins of pseudohomothallism. Likelihood ratio tests of substitution rates among branches in the phylogeny indicate that reproductive mode is an important factor driving genome evolution in Neurospora. First, an increased level of non-synonymous/synonymous substitutions in branches delineating homothallic taxa was found, suggesting a reduced efficiency of purifying selection in these taxa. Furthermore, elevated nucleotide substitution rates were found in heterothallic, conidia-producing, lineages as compared to the homothallic non-conidiating lineages. The latter finding is likely due to the presence of conidia, i.e., a higher rate of mitotic divisions inducing mutations, and/or that the homothallic taxa have evolved a lower mutation rate to avoid genomic degeneration.
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| 5. |
- Nygren, Kristiina, et al.
(författare)
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Analyses of expressed sequence tags in Neurospora reveal rapid evolution of genes associated with the early stages of sexual reproduction in fungi
- 2012
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 12, s. 229-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The broadly accepted pattern of rapid evolution of reproductive genes is primarily based on studies of animal systems, although several examples of rapidly evolving genes involved in reproduction are found in diverse additional taxa. In fungi, genes involved in mate recognition have been found to evolve rapidly. However, the examples are too few to draw conclusions on a genome scale. Results: In this study, we performed microarray hybridizations between RNA from sexual and vegetative tissues of two strains of the heterothallic (self-sterile) filamentous ascomycete Neurospora intermedia, to identify a set of sex-associated genes in this species. We aligned Expressed Sequence Tags (ESTs) from sexual and vegetative tissue of N. intermedia to orthologs from three closely related species: N. crassa, N. discreta and N. tetrasperma. The resulting four-species alignments provided a dataset for molecular evolutionary analyses. Our results confirm a general pattern of rapid evolution of fungal sex-associated genes, compared to control genes with constitutive expression or a high relative expression during vegetative growth. Among the rapidly evolving sex-associated genes, we identified candidates that could be of importance for mating or fruiting-body development. Analyses of five of these candidate genes from additional species of heterothallic Neurospora revealed that three of them evolve under positive selection. Conclusions: Taken together, our study represents a novel finding of a genome-wide pattern of rapid evolution of sex-associated genes in the fungal kingdom, and provides a list of candidate genes important for reproductive isolation in Neurospora.
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| 6. |
- Olofsson, Anna, 1971-, et al.
(författare)
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The mutual constitution of risk and inequalities : Intersectional risk theory
- 2014
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Ingår i: Health, Risk and Society. - : Informa UK Limited. - 1369-8575 .- 1469-8331. ; 16:5, s. 417-430
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we examine the conceptual importance of integrating risk and intersectionality theory for the study of how risk and various forms of inequality intersect and are mutually constitutive. We argue that an intersectional perspective can advance risk research by incorporating more effectively the role of such social categories as gender and race into the analysis of ‘risk’ as an empirical phenomenon. In doing so, the intersectional perspective articulates more clearly the connection between the social construction of risk and, on the one hand, the reproduction of new and complex social inequalities and, on the other, intersections of social class, gender, ethnicity and other social categorisations. We trace the intellectual division between risk and feminist-inspired intersectionality research, showing how these approaches can be aligned to study, for example, risk-based welfare and social policy. We use a discussion of general directions within welfare policy to illustrate how an intersectional perspective can be used to show the ways in which new governance strategies create new divisions and reproduce existing forms of social inequality. We conclude the article with a call for a new research agenda to integrate intersectional frameworks with risk theory in order to provide a more nuanced analysis of the relationship between social inequality and risk.
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