A Spontaneous Mutation in Contactin 1 in the Mouse

Mutations in the gene encoding the immunoglobulin-superfamily member cell adhesion molecule contactin1 (CNTN1) cause lethal congenital myopathy in human patients and neurodevelopmental phenotypes in knockout mice. Whether the mutant mice provide an accurate model of the human disease is unclear; resolving this will require additional functional tests of the neuromuscular system and examination of Cntn1 mutations on different genetic backgrounds that may influence the phenotype. Toward these ends, we have analyzed a new, spontaneous mutation in the mouse Cntn1 gene that arose in a BALB/c genetic background. The overt phenotype is very similar to the knockout of Cntn1, with affected animals having reduced body weight, a failure to thrive, locomotor abnormalities, and a lifespan of 2–3 weeks. Mice homozygous for the new allele have CNTN1 protein undetectable by western blotting, suggesting that it is a null or very severe hypomorph. In an analysis of neuromuscular function, neuromuscular junctions had normal morphology, consistent with previous studies in knockout mice, and the muscles were able to generate appropriate force when normalized for their reduced size in late stage animals. Therefore, the Cntn1 mutant mice do not show evidence for a myopathy, but instead the phenotype is likely to be caused by dysfunction in the nervous system. Given the similarity of CNTN1 to other Ig-superfamily proteins such as DSCAMs, we also characterized the expression and localization of Cntn1 in the retinas of mutant mice for developmental defects. Despite widespread expression, no anomalies in retinal anatomy were detected histologically or using a battery of cell-type specific antibodies. We therefore conclude that the phenotype of the Cntn1 mice arises from dysfunction in the brain, spinal cord or peripheral nervous system, and is similar in either a BALB/c or B6;129;Black Swiss background, raising a possible discordance between the mouse and human phenotypes resulting from Cntn1 mutations

Lowering β-Amyloid Levels Rescues Learning and Memory in a Down Syndrome Mouse Model

β-amyloid levels are elevated in Down syndrome (DS) patients throughout life and are believed to cause Alzheimer's disease (AD) in adult members of this population. However, it is not known if β-amyloid contributes to intellectual disability in younger individuals. We used a γ-secretase inhibitor to lower β-amyloid levels in young mice that model DS. This treatment corrected learning deficits characteristic of these mice, suggesting that β-amyloid-lowering therapies might improve cognitive function in young DS patients

Oklahoma Christian College

Commencement address given by Judge William Guy Davisson, May 27, 1966. Mr. Davisson was an Ardmore attorney

Accurate and Efficient Calculation of Excited Vibrational States From Quartic Potential Energy Surfaces

Vibrational anharmonicity and resonances frequently complicate assignment of vibrational spectra. In order to analyse such spectra, these effects can be calculated from ab initio quartic potential energy surfaces (PESs) using second-order vibrational theory with resonances (VPT2+K). This study compares the accuracies of using the cc-pVTZ basis set, the aug-cc-pVQZ basis set, and a hybrid approach that uses the cc-pVTZ basis set for the equilibrium geometry and quadratic force constants and the aug-cc-pVQZ basis set for the cubic and quartic force constants. Quartic PESs are computed using these basis sets for H2O, H2CO, HFCO, SCCl2, and their deuterated analogs with the CCSD(T) method. The computed PESs are assessed by comparing experimentally determined and theoretically calculated spectroscopic constants. The average absolute difference (h ) between theoretical and experimental zero-point energy-corrected harmonic frequencies (omega(0)(i)) decreases by 54.7% when the hybrid approach is used instead of the cc-pVTZ basis, but decreases by only an additional 2.3% when the aug-cc-pVQZ basis is used. The computed PESs are also assessed by comparing predicted and observed vibrational energy states. The weighted average root-mean-square (RMS) difference between predicted and observed vibrational energy levels decreases by 42.3% when the hybrid approach is used instead of cc-pVTZ, but decreases by only an additional 4.0% when aug-cc-pVQZ is used. These results demonstrate that calculations performed using the hybrid basis set approach, which have a substantially lower computational cost, are comparable in accuracy to those performed using the aug-cc-pVQZ basis set

An Analysis Of Firm Motivation In The Defense Industry

This article considers the performance of firms in the defense industry. The analysis suggests that in terms of profitability and revenue there is no advantage to be gained by a firm from increasing the proportion of its total sales which go to the military. As a corollary to this proposition we find that the firms examined are profit maximizers and are not content to simply maximize revenue. Another conclusion to be drawn from the empirical analysis that there is a difference between high and low defense commitment firms and that this distinction occurs when the percentage of sale to the government reaches the seventeen percent level