Vanderbilt University

About: Vanderbilt University is a education organization based out in Nashville, Tennessee, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 45066 authors who have published 106528 publications receiving 5435039 citations. The organization is also known as: Vandy.

Recurrent Rearrangements of Chromosome 1q21.1 and Variable Pediatric Phenotypes

Abstract: BACKGROUND: Duplications and deletions in the human genome can cause disease or predispose persons to disease. Advances in technologies to detect these changes allow for the routine identification of submicroscopic imbalances in large numbers of patients. METHODS: We tested for the presence of microdeletions and microduplications at a specific region of chromosome 1q21.1 in two groups of patients with unexplained mental retardation, autism, or congenital anomalies and in unaffected persons. RESULTS: We identified 25 persons with a recurrent 1.35-Mb deletion within 1q21.1 from screening 5218 patients. The microdeletions had arisen de novo in eight patients, were inherited from a mildly affected parent in three patients, were inherited from an apparently unaffected parent in six patients, and were of unknown inheritance in eight patients. The deletion was absent in a series of 4737 control persons (P=1.1x10(-7)). We found considerable variability in the level of phenotypic expression of the microdeletion; phenotypes included mild-to-moderate mental retardation, microcephaly, cardiac abnormalities, and cataracts. The reciprocal duplication was enriched in nine children with mental retardation or autism spectrum disorder and other variable features (P=0.02). We identified three deletions and three duplications of the 1q21.1 region in an independent sample of 788 patients with mental retardation and congenital anomalies. CONCLUSIONS: We have identified recurrent molecular lesions that elude syndromic classification and whose disease manifestations must be considered in a broader context of development as opposed to being assigned to a specific disease. Clinical diagnosis in patients with these lesions may be most readily achieved on the basis of genotype rather than phenotype.

Microduplications of 16p11.2 are Associated with Schizophrenia

Abstract: Recurrent microdeletions and microduplications of a 600-kb genomic region of chromosome 16p11.2 have been implicated in childhood-onset developmental disorders1, 2, 3. We report the association of 16p11.2 microduplications with schizophrenia in two large cohorts. The microduplication was detected in 12/1,906 (0.63%) cases and 1/3,971 (0.03%) controls (P = 1.2 10-5, OR = 25.8) from the initial cohort, and in 9/2,645 (0.34%) cases and 1/2,420 (0.04%) controls (P = 0.022, OR = 8.3) of the replication cohort. The 16p11.2 microduplication was associated with a 14.5-fold increased risk of schizophrenia (95% CI (3.3, 62)) in the combined sample. A meta-analysis of datasets for multiple psychiatric disorders showed a significant association of the microduplication with schizophrenia (P = 4.8 10-7), bipolar disorder (P = 0.017) and autism (P = 1.9 10-7). In contrast, the reciprocal microdeletion was associated only with autism and developmental disorders (P = 2.3 10-13). Head circumference was larger in patients with the microdeletion than in patients with the microduplication (P = 0.0007).

Helicobacter pylori and the Pathogenesis of Gastroduodenal Inflammation

Abstract: Helicobacter pylori is a newly discovered gram-negative bacterium that lives in the human stomach and duodenum. Infection with this organism is strongly associated with type B antral gastritis and with peptic ulcer disease. Recent evidence from human volunteer studies, therapeutic trials with antimicrobial agents, and experiments with animal models indicates that H. pylori plays an etiologic role in the pathogenesis of type B gastritis. Gastric metaplasia is observed in virtually all patients with duodenal ulceration and may be the target tissue for these bacteria in the duodenum. Patients in whom H. pylori can no longer be identified after ulcer therapy remain in remission for significantly longer than do patients in whom the organism can be found. The data concerning an etiologic role of H. pylori in duodenal ulcer are suggestive but not yet conclusive. Present antimicrobial therapy can suppress but usually cannot eliminate H. pylori.

On Effect Size

Abstract: The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension, measure/index, and value), outline 10 corollaries that follow from our definition, and review ideal qualities of effect sizes. Our definition of effect size is general and subsumes many existing definitions of effect size. We define effect size as a quantitative reflection of the magnitude of some phenomenon that is used for the purpose of addressing a question of interest. Our definition of effect size is purposely more inclusive than the way many have defined and conceptualized effect size, and it is unique with regard to linking effect size to a question of interest. Additionally, we review some important developments in the effect size literature and discuss the importance of accompanying an effect size with an interval estimate that acknowledges the uncertainty with which the population value of the effect size has been estimated. We hope that this article will facilitate discussion and improve the practice of reporting and interpreting effect sizes.

The Choice of Payment Method in European Mergers and Acquisitions

Abstract: We study merger and acquisition (M&A) payment choices of European bidders for publicly and privately held targets in the 1997–2000 period. Europe is an ideal venue for studying the importance of corporate governance in making M&A payment choices, given the large number of closely held firms and the wide range of capital markets, institutional settings, laws, and regulations. The tradeoff between corporate governance concerns and debt financing constraints is found to have a large bearing on the bidder's payment choice. Consistent with earlier evidence, we find that several deal and target characteristics significantly affect the method of payment choice.