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.

Exposure to HIV-1 directly impairs mucosal epithelial barrier integrity allowing microbial translocation.

Abstract: While several clinical studies have shown that HIV-1 infection is associated with increased permeability of the intestinal tract, there is very little understanding of the mechanisms underlying HIV-induced impairment of mucosal barriers. Here we demonstrate that exposure to HIV-1 can directly breach the integrity of mucosal epithelial barrier, allowing translocation of virus and bacteria. Purified primary epithelial cells (EC) isolated from female genital tract and T84 intestinal cell line were grown to form polarized, confluent monolayers and exposed to HIV-1. HIV-1 X4 and R5 tropic laboratory strains and clinical isolates were seen to reduce transepithelial resistance (TER), a measure of monolayer integrity, by 30–60% following exposure for 24 hours, without affecting viability of cells. The decrease in TER correlated with disruption of tight junction proteins (claudin 1, 2, 4, occludin and ZO-1) and increased permeability. Treatment of ECs with HIV envelope protein gp120, but not HIV tat, also resulted in impairment of barrier function. Neutralization of gp120 significantly abrogated the effect of HIV. No changes to the barrier function were observed when ECs were exposed to Env defective mutant of HIV. Significant upregulation of inflammatory cytokines, including TNF-α, were seen in both intestinal and genital epithelial cells following exposure to HIV-1. Neutralization of TNF-α reversed the reduction in TERs. The disruption in barrier functions was associated with viral and bacterial translocation across the epithelial monolayers. Collectively, our data shows that mucosal epithelial cells respond directly to envelope glycoprotein of HIV-1 by upregulating inflammatory cytokines that lead to impairment of barrier functions. The increased permeability could be responsible for small but significant crossing of mucosal epithelium by virus and bacteria present in the lumen of mucosa. This mechanism could be particularly relevant to mucosal transmission of HIV-1 as well as immune activation seen in HIV-1 infected individuals.

Asthma control during the year after bronchial thermoplasty

Abstract: BACKGROUND: Bronchial thermoplasty is a bronchoscopic procedure to reduce the mass of airway smooth muscle and attenuate bronchoconstriction. We examined the effect of bronchial thermoplasty on the control of moderate or severe persistent asthma. METHODS: We randomly assigned 112 subjects who had been treated with inhaled corticosteroids and long-acting beta2-adrenergic agonists (LABA) and in whom asthma control was impaired when the LABA were withdrawn to either bronchial thermoplasty or a control group. The primary outcome was the frequency of mild exacerbations, calculated during three scheduled 2-week periods of abstinence from LABA at 3, 6, and 12 months. Airflow, airway responsiveness, asthma symptoms, the number of symptom-free days, use of rescue medication, and scores on the Asthma Quality of Life Questionnaire (AQLQ) and the Asthma Control Questionnaire (ACQ) were also assessed. RESULTS: The mean rate of mild exacerbations, as compared with baseline, was reduced in the bronchial-thermoplasty group but was unchanged in the control group (change in frequency per subject per week, -0.16+/-0.37 vs. 0.04+/-0.29; P=0.005). At 12 months, there were significantly greater improvements in the bronchial-thermoplasty group than in the control group in the morning peak expiratory flow (39.3+/-48.7 vs. 8.5+/-44.2 liters per minute), scores on the AQLQ (1.3+/-1.0 vs. 0.6+/-1.1) and ACQ (reduction, 1.2+/-1.0 vs. 0.5+/-1.0), the percentage of symptom-free days (40.6+/-39.7 vs. 17.0+/-37.9), and symptom scores (reduction, 1.9+/-2.1 vs. 0.7+/-2.5) while fewer puffs of rescue medication were required. Values for airway responsiveness and forced expiratory volume in 1 second did not differ significantly between the two groups. Adverse events immediately after treatment were more common in the bronchial-thermoplasty group than in the control group but were similar during the period from 6 weeks to 12 months after treatment. CONCLUSIONS: Bronchial thermoplasty in subjects with moderate or severe asthma results in an improvement in asthma control. (ClinicalTrials.gov number, NCT00214526 [ClinicalTrials.gov].).

Feeling the Beat: Movement Influences Infant Rhythm Perception

Abstract: We hear the melody in music, but we feel the beat. We demonstrate that the perception of musical rhythm is a multisensory experience in infancy. In particular, movement of the body, by bouncing on every second versus every third beat of an ambiguous auditory rhythm pattern, influences whether that auditory rhythm pattern is encoded in duple form (a march) or in triple form (a waltz). Visual information is not necessary for the effect, indicating that it likely reflects a strong, early-developing interaction between auditory and vestibular information in the human nervous system.

Sex and the single hemisphere: specialization of the right hemisphere for spatial processing

Abstract: Specialization of the right hemisphere for spatial processing was studied in 200 normal boys and girls between 6 and 13 years of age. Boys performed in a manner consistent with right hemisphere specialization as early as the age of 6. Girls showed evidence of bilateral representation until the age of 13. The results suggest a sexual dimorphism in the neural organization underlying cognition during a major period of childhood. The results, which have implications for reading instruction, are discussed in terms of a possible sex difference in neural plasticity during development and the clinical consequences of such a difference.