McMaster University

About: McMaster University is a education organization based out in Hamilton, Ontario, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 41361 authors who have published 101269 publications receiving 4251422 citations.

Adjuvant Chemotherapy Guided by a 21-Gene Expression Assay in Breast Cancer

Abstract: Background The recurrence score based on the 21-gene breast cancer assay predicts chemotherapy benefit if it is high and a low risk of recurrence in the absence of chemotherapy if it is low; however, there is uncertainty about the benefit of chemotherapy for most patients, who have a midrange score. Methods We performed a prospective trial involving 10,273 women with hormone-receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative, axillary node–negative breast cancer. Of the 9719 eligible patients with follow-up information, 6711 (69%) had a midrange recurrence score of 11 to 25 and were randomly assigned to receive either chemoendocrine therapy or endocrine therapy alone. The trial was designed to show noninferiority of endocrine therapy alone for invasive disease–free survival (defined as freedom from invasive disease recurrence, second primary cancer, or death). Results Endocrine therapy was noninferior to chemoendocrine therapy in the analysis of invasive disease–free surv...

Hand and sex differences in the isthmus and genu of the human corpus callosum. A postmortem morphological study

Abstract: The midsagittal area of the corpus callosum was measured in its entirety and in seven subdivisions in a sample of 50 brains consecutively obtained from autopsies of individuals who had neuropsychological testing before death. A 12-item test of hand preference was used as an index of the pattern of interhemispheric functional asymmetry. Callosal size was analysed for two factors: hand preference, classified as consistent-right-hand preference (CRH) versus non consistent-right-hand preference, and sex. The group of nCRH (n = 18) was found to have a larger overall callosal area, with the greatest difference occurring in the posterior body segments, especially the isthmus. The isthmus probably includes interhemispheric fibres from posterior parietal and superior temporal cortex which involves cortical regions related to functional asymmetry. The results of variation in callosal morphology are discussed as part of a possible substrate of functional asymmetry and due to variation in axonal elimination in early brain development. Sex differences were found in several aspects of callosal anatomy. (1) The difference between hand groups in the posterior body occurred in interaction with sex:handedness was a factor in callosal size in males (n = 15), but not in females (n = 35). This result is consistent with the general hypothesis of females having less clear lateralization than males. (2) Females did not have a larger overall callosum or a larger splenium, either in absolute size or size proportional to brain weight. The latter measure was considered since callosal area correlated with cerebrum weight (r = 0.48). In contrast, female of both hand groups were found to have a larger proportional isthmus compared to CRH males. (3) Of all callosal regions, only the genu and a part of the anterior body were found to be larger in absolute size in males than females. (4) Callosal size decreased with chronological age in males, but not in females.

Service utilization for lifetime mental disorders in U.S. adolescents: results of the National Comorbidity Survey-Adolescent Supplement (NCS-A).

Abstract: Objective Mental health policy for youth has been constrained by a paucity of nationally representative data concerning patterns and correlates of mental health service utilization in this segment of the population. The objectives of this investigation were to examine the rates and sociodemographic correlates of lifetime mental health service use by severity, type, and number of DSM-IV disorders in the National Comorbidity Survey–Adolescent Supplement. Method Face-to-face survey of mental disorders from 2002 to 2004 using a modified version of the fully structured World Health Organization Composite International Diagnostic Interview in a nationally representative sample of 6,483 adolescents 13 to 18 years old for whom information on service use was available from an adolescent and a parent report. Total and sector-specific mental health service use was also assessed. Results Approximately one third of adolescents with mental disorders received services for their illness (36.2%). Although disorder severity was significantly associated with an increased likelihood of receiving treatment, half of adolescents with severely impairing mental disorders had never received mental health treatment for their symptoms. Service rates were highest in those with attention-deficit/hyperactivity disorder (59.8%) and behavior disorders (45.4%), but fewer than one in five affected adolescents received services for anxiety, eating, or substance use disorders. Comorbidity and severe impairment were strongly associated with service utilization, particularly in youth with behavior disorders. Hispanic and non-Hispanic Black adolescents were less likely than their White counterparts to receive services for mood and anxiety disorders, even when such disorders were associated with severe impairment. Conclusions Despite advances in public awareness of mental disorders in youth, a substantial proportion of young people with severe mental disorders have never received specialty mental health care. Marked racial disparities in lifetime rates of mental health treatment highlight the urgent need to identify and combat barriers to the recognition and treatment of these conditions.

W/kit gene required for interstitial cells of Cajal and for intestinal pacemaker activity

Abstract: The pacemaker activity in the mammalian gut is responsible for generating anally propagating phasic contractions. The cellular basis for this intrinsic activity is unknown. The smooth muscle cells of the external muscle layers and the innervated cellular network of interstitial cells of Cajal, which is closely associated with the external muscle layers of the mammalian gut, have both been proposed to stimulate pacemaker activity. The interstitial cells of Cajal were identified in the last century but their developmental origin and function have remained unclear. Here we show that the interstitial cells of Cajal express the Kit receptor tyrosine kinase. Furthermore, mice with mutations in the dominant white spotting (W) locus, which have cellular defects in haematopoiesis, melanogenesis and gametogenesis as a result of mutations in the Kit gene, also lack the network of interstitial cells of Cajal associated with Auerbach's nerve plexus and intestinal pacemaker activity.