Sunnybrook Health Sciences Centre

About: Sunnybrook Health Sciences Centre is a healthcare organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Population & Medicine. The organization has 7689 authors who have published 15236 publications receiving 523019 citations. The organization is also known as: Sunnybrook.

Predisposition to abacavir hypersensitivity conferred by HLA-B*5701 and a haplotypic Hsp70-Hom variant

Abstract: Susceptibility to a clinically significant drug hypersensitivity syndrome associated with abacavir use seems to have a strong genetic component. We have previously shown that the presence of HLA-B*5701 strongly predicts abacavir hypersensitivity and have identified a potential susceptibility locus within a 300-kb region between the MEGT1 and C4A6 loci in the central MHC. We now report the results of fine recombinant genetic mapping in an expanded patient population of 248 consecutive, fully ascertained, abacavir-exposed individuals in the Western Australian HIV Cohort Study, in which 18 cases of definite abacavir hypersensitivity (7.3%) and 230 tolerant controls were identified. Haplotype mapping within patients with allelic markers of the 57.1 ancestral haplotype suggests a susceptibility locus within the 14-kb Hsp70 gene cluster. HLA-B*5701 was present in 94.4% of hypersensitive cases compared with 1.7% of controls (odds ratio, 960; P < 0.00001). A haplotypic nonsynonymous polymorphism of Hsp70-Hom (HspA1L, resulting from the substitution of residue M493T in the peptide-binding subunit) was found in combination with HLA-B*5701 in 94.4% of hypersensitive cases and 0.4% of controls (odds ratio, 3,893; P < 0.00001). Individuals with abacavir hypersensitivity demonstrated increased monocyte tumor necrosis factor expression in response to ex vivo abacavir stimulation, which was abrogated with CD8+ T cell depletion. These data indicate that the concurrence of HLA-B*5701 and Hsp70-Hom M493T alleles is necessary for the development of abacavir hypersensitivity, which is likely to be mediated by an HLA-B*5701-restricted immune response to abacavir.

Middle East Respiratory Syndrome

Abstract: Between September 2012 and January 20, 2017, the World Health Organization (WHO) received reports from 27 countries of 1879 laboratory-confirmed cases in humans of the Middle East respiratory syndrome (MERS) caused by infection with the MERS coronavirus (MERS-CoV) and at least 659 related deaths. Cases of MERS-CoV infection continue to occur, including sporadic zoonotic infections in humans across the Arabian Peninsula, occasional importations and associated clusters in other regions, and outbreaks of nonsustained human-to-human transmission in health care settings. Dromedary camels are considered to be the most likely source of animal-to-human transmission. MERS-CoV enters host cells after binding the dipeptidyl peptidase 4 (DPP-4) receptor and the carcinoembryonic antigen–related cell-adhesion molecule 5 (CEACAM5) cofactor ligand, and it replicates efficiently in the human respiratory epithelium. Illness begins after an incubation period of 2 to 14 days and frequently results in hypoxemic respiratory failure and the need for multiorgan support. However, asymptomatic and mild cases also occur. Real-time reverse-transcription–polymerase-chain-reaction (RT-PCR) testing of respiratory secretions is the mainstay for diagnosis, and samples from the lower respiratory tract have the greatest yield among seriously ill patients. There is no antiviral therapy of proven efficacy, and thus treatment remains largely supportive; potential vaccines are at an early developmental stage. There are multiple gaps in knowledge regarding the evolution and transmission of the virus, disease pathogenesis, treatment, and prospects for a vaccine. The ongoing occurrence of MERS in humans and the associated high mortality call for a continued collaborative approach toward gaining a better understanding of the infection both in humans and in animals.MERS-CoV was first identified in September 2012 in a patient from Saudi Arabia who had hypoxemic respiratory failure and multiorgan illness. Subsequent cases have included infections in humans across the Arabian Peninsula, occasional importations and associated clusters in other regions, and outbreaks of nonsustained human-to-human transmission in health care settings (Fig. 1).

Randomized trial comparing 3 approaches to the initial respiratory management of preterm neonates

Abstract: OBJECTIVE: We designed a multicenter randomized trial to compare 3 approaches to the initial respiratory management of preterm neonates: prophylactic surfactant followed by a period of mechanical ventilation (prophylactic surfactant [PS]); prophylactic surfactant with rapid extubation to bubble nasal continuous positive airway pressure (intubate-surfactant-extubate [ISX]) or initial management with bubble continuous positive airway pressure and selective surfactant treatment (nCPAP). DESIGN/METHODS: Neonates born at 26 0 7 to 29 6 7 weeks9 gestation were enrolled at participating Vermont Oxford Network centers and randomly assigned to PS, ISX, or nCPAP groups before delivery. Primary outcome was the incidence of death or bronchopulmonary dysplasia (BPD) at 36 weeks9 postmenstrual age. RESULTS: 648 infants enrolled at 27 centers. The study was halted before the desired sample size was reached because of declining enrollment. When compared with the PS group, the relative risk of BPD or death was 0.78 (95% confidence interval: 0.59–1.03) for the ISX group and 0.83 (95% confidence interval: 0.64–1.09) for the nCPAP group. There were no statistically significant differences in mortality or other complications of prematurity. In the nCPAP group, 48% were managed without intubation and ventilation, and 54% without surfactant treatment. CONCLUSIONS: Preterm neonates were initially managed with either nCPAP or PS with rapid extubation to nCPAP had similar clinical outcomes to those treated with PS followed by a period of mechanical ventilation. An approach that uses early nCPAP leads to a reduction in the number of infants who are intubated and given surfactant.

Coronary angiography with magnetization-prepared T2 contrast.

Abstract: A magnetization-prepared, T2-weighted sequence (T2 Prep) is used to suppress muscle and venous structures. When combined with lipid suppression, this technique improves the visualization of the coronary arteries. T2 Prep was designed to be rebust in the presence of flow as well as B0 and B1 inhomogeneities and may be combined with virtually any imaging technique. Here, it is implemented with both a single-slice spiral acquisition and a multi-slice spiral method that acquires up to 15 slices in a single breath-holding interval.