| 1. |
- Heard-Costa, Nancy L, et al.
(author)
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NRXN3 is a novel locus for waist circumference : a genome-wide association study from the CHARGE Consortium
- 2009
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In: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 5:6, s. e1000539-
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Journal article (peer-reviewed)abstract
- Central abdominal fat is a strong risk factor for diabetes and cardiovascular disease. To identify common variants influencing central abdominal fat, we conducted a two-stage genome-wide association analysis for waist circumference (WC). In total, three loci reached genome-wide significance. In stage 1, 31,373 individuals of Caucasian descent from eight cohort studies confirmed the role of FTO and MC4R and identified one novel locus associated with WC in the neurexin 3 gene [NRXN3 (rs10146997, p = 6.4×10−7)]. The association with NRXN3 was confirmed in stage 2 by combining stage 1 results with those from 38,641 participants in the GIANT consortium (p = 0.009 in GIANT only, p = 5.3×10−8 for combined analysis, n = 70,014). Mean WC increase per copy of the G allele was 0.0498 z-score units (0.65 cm). This SNP was also associated with body mass index (BMI) [p = 7.4×10−6, 0.024 z-score units (0.10 kg/m2) per copy of the G allele] and the risk of obesity (odds ratio 1.13, 95% CI 1.07–1.19; p = 3.2×10−5 per copy of the G allele). The NRXN3 gene has been previously implicated in addiction and reward behavior, lending further evidence that common forms of obesity may be a central nervous system-mediated disorder. Our findings establish that common variants in NRXN3 are associated with WC, BMI, and obesity.
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| 2. |
- Pace, Rishika A., et al.
(author)
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Collagen VI glycine mutations: Perturbed assembly and a spectrum of clinical severity
- 2008
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In: Annals of Neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 64:3, s. 294-303
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Journal article (peer-reviewed)abstract
- Objective: The collagen VI muscular dystrophies, Bethlem myopathy and Ullrich congenital muscular dystrophy, form a continuum of clinical phenotypes. Glycine mutations in the triple helix have been identified in both Bethlem and Ullrich congenital muscular dystrophy, but it is not known why they cause these different phenotypes. Methods: We studied eight new patients who presented with a spectrum of clinical severity, screened the three collagen VI messenger RNA for mutations, and examined collagen VI biosynthesis and the assembly pathway. Results: All eight patients had heterozygous glycine mutations toward the N-terminal end of the triple helix. The mutations produced two assembly phenotypes. In the first patient group, collagen VI dimers accumulated in the cell but not the medium, microfibril formation in the medium was moderately reduced, and the amount of collagen VI in the extracellular matrix was not significantly altered. The second group had more severe assembly defects: some secreted collagen VI tetramers were not disulfide bonded, microfibril formation in the medium was severely compromised, and collagen VI in the extracellular matrix was reduced. Interpretation: These data indicate that collagen VI glycine mutations impair the assembly pathway in different ways and disease severity correlates with the assembly abnormality. In mildly affected patients, normal amounts of collagen VI were deposited in the fibroblast matrix, whereas in patients with moderate-to-severe disability, assembly defects led to a reduced collagen VI fibroblast matrix. This study thus provides an explanation for how different glycine mutations produce a spectrum of clinical severity.
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| 3. |
- Baker, Naomi L., et al.
(author)
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Molecular consequences of dominant Bethlem myopathy collagen VI mutations
- 2007
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In: Annals of Neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 62:4, s. 390-405
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Journal article (peer-reviewed)abstract
- Objective: Dominant mutations in the three collagen VI genes cause Bethlem myopathy, a disorder characterized by proximal muscle weakness and commonly contractures of the fingers, wrists, and ankles. Although more than 20 different dominant mutations have been identified in Bethlem myopathy patients, the biosynthetic consequences of only a subset of these have been studied, and in many cases, the pathogenic mechanisms remain unknown. Methods: We have screened fourteen Bethlem myopathy patients for collagen VI mutations and performed detailed analyses of collagen VI biosynthesis and intracellular and extracellular assembly. Results: Collagen VI abnormalities were identified in eight patients. One patient produced around half the normal amount of alpha 1(VI) messenger RNA and reduced amounts of collagen VI protein. Two patients had a previously reported mutation causing skipping of COL6A1 exon 14, and three patients had novel mutations leading to in-frame deletions toward the N-terminal end of the triple-helical domain. These mutations have different and complex effects on collagen VI intracellular and extracellular assembly. Two patients had single amino acid substitutions in the A-domains of COL6A2 and COL6A3. Collagen VI intracellular and extracellular assembly was normal in one of these patients. Interpretation: The key to dissecting the pathogenic mechanisms of collagen VI mutations lies in detailed analysis of collagen VI biosynthesis and assembly. The majority of mutations result in secretion and deposition of structurally abnormal collagen VI. However, one A-domain mutation had no detectable effect on assembly, suggesting that it acts by compromising collagen VI interactions in the extracellular matrix of muscle.
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| 4. |
- Boukhvalov, D. W., et al.
(author)
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Electronic structure of a Mn-12 molecular magnet : Theory and experiment
- 2007
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In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:1, s. 014419-
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Journal article (peer-reviewed)abstract
- We used site-selective and element-specific resonant inelastic x-ray scattering (RIXS) to study the electronic structure and the electron interaction effects in the molecular magnet [Mn12O12(CH3COO)(16)(H2O)(4)]center dot 2CH(3)COOH center dot 4H(2)O, and compared the experimental data with the results of local spin density approximation +U electron structure calculations which include the on-site Coulomb interactions. We found a good agreement between theory and experiment for the Coulomb repulsion parameter U = 4 eV. In particular, the p-d band separation of 1.8 eV has been found from the RIXS spectra, which is in accordance with the calculations. Similarly, the positions of the peaks in the XPS spectra agree with the calculated densities of p and d states. Using the results of the electronic structure calculations, we determined the intramolecular exchange parameters, and used them for diagonalization of the Mn-12 spin Hamiltonian. The calculated exchanges gave the correct ground state with the total spin S = 10.
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| 5. |
- Carducci, Michael A., et al.
(author)
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A phase 3 randomized controlled trial of the efficacy and safety of atrasentan in men with metastatic hormone-refractory prostate cancer
- 2007
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In: Cancer. - : Wiley. - 1097-0142 .- 0008-543X. ; 110:9, s. 1959-1966
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Journal article (peer-reviewed)abstract
- BACKGROUND. The objective of this study was to evaluate the efficacy and safety of atrasentan (Xinlay), a selective endothelin-A receptor antagonist, in patients with metastatic hormone- refractory prostate cancer (HRPC). METHODS. This multinational, double-blind, placebo-controlled trial enrolled 809 men with metastatic HRPC. Patients were randomized 1:1 to receive either atrasentan 10 mg per day or placebo. The primary endpoint was time to disease progression (TTP), which was determined according to radiographic and clinical measures. Analyses of overall survival and changes in biomarkers also were performed. RESULTS. Atrasentan did not reduce the risk of disease progression relative to placebo (hazards ratio, 0.89; 95% confidence interval, 0.76-1.04; P =.136). Most patients progressed radiographically at the first 12-week bone scan without concomitant clinical progression. In exploratory analyses, increases from baseline to final bone alkaline phosphatase (BAP) and prostate-specific antigen (PSA) levels were significantly lower with atrasentan treatment (P <.05 for each). The median time to BAP progression (> 50% increase from nadir) was twice as long with atrasentan treatment (505 days vs 254 days; P <.01). The delay in time to PSA progression did not reach statistical significance. Atrasentan generally was tolerated well, and the most common adverse events associated with treatment were headache, rhinitis, and peripheral edema, reflecting the vasodilatory and fluid-retention properties of endothelin-A receptor antagonism. CONCLUSIONS. Atrasentan did not delay disease progression in men with metastatic HRPC despite evidence of biologic effects on PSA and BAP as markers of disease burden.
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