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Objective To examine the effect of surgeon sex on postoperative outcomes of patients undergoing common surgical procedures.Design Population based, retrospective, matched cohort study from 2007 to 2015.Setting Population based cohort of all patients treated in Ontario, Canada.Participants Patients undergoing one of 25 surgical procedures performed by a female surgeon were matched by patient age, patient sex, comorbidity, surgeon volume, surgeon age, and hospital to patients undergoing the same operation by a male surgeon.Interventions Sex of treating surgeon.Main outcome measure The primary outcome was a composite of death, readmission, and complications. We compared outcomes between groups using generalised estimating equations.Results 104 630 patients were treated by 3314 surgeons, 774 female and 2540 male. Before matching, patients treated by female doctors were more likely to be female and younger but had similar comorbidity, income, rurality, and year of surgery. After matching, the groups were comparable. Fewer patients treated by female surgeons died, were readmitted to hospital, or had complications within 30 days (5810 of 52 315, 11.1%, 95% confidence interval 10.9% to 11.4%) than those treated by male surgeons (6046 of 52 315, 11.6%, 11.3% to 11.8%; adjusted odds ratio 0.96, 0.92 to 0.99, P=0.02). Patients treated by female surgeons were less likely to die within 30 days (adjusted odds ratio 0.88; 0.79 to 0.99, P=0.04), but there was no significant difference in readmissions or complications. Stratified analyses by patient, physician, and hospital characteristics did not significant modify the effect of surgeon sex on outcome. A retrospective analysis showed no difference in outcomes by surgeon sex in patients who had emergency surgery, where patients do not usually choose their surgeon.Conclusions After accounting for patient, surgeon, and hospital characteristics, patients treated by female surgeons had a small but statistically significant decrease in 30 day mortality and similar surgical outcomes (length of stay, complications, and readmission), compared with those treated by male surgeons. These findings support the need for further examination of the surgical outcomes and mechanisms related to physicians and the underlying processes and patterns of care to improve mortality, complications, and readmissions for all patients.

Concepts: Male, Statistics, Hospital, Surgery, Statistical significance, Physician, Surgeon, American College of Surgeons

23

The metabolic effects of omega-6 polyunsaturated fatty acids (PUFAs) remain contentious, and little evidence is available regarding their potential role in primary prevention of type 2 diabetes. We aimed to assess the associations of linoleic acid and arachidonic acid biomarkers with incident type 2 diabetes.

Concepts: Nutrition, Fatty acid, Fatty acids, Essential fatty acid, Omega-6 fatty acid, Linoleic acid, Arachidonic acid, Essential fatty acid interactions

23

The evolution of powered flight is a major innovation that has facilitated the success of insects. Previously, studies of birds, bats, and insects have detected molecular signatures of differing selection regimes in energy-related genes associated with flight evolution and/or loss. Here, using DNA sequences from more than 1000 nuclear and mitochondrial protein-coding genes obtained from insect transcriptomes, we conduct a broader exploration of which gene categories display positive and relaxed selection at the origin of flight as well as with multiple independent losses of flight. We detected a number of categories of nuclear genes more often under positive selection in the lineage leading to the winged insects (Pterygota), related to catabolic processes such as proteases, as well as splicing-related genes. Flight loss was associated with relaxed selection signatures in splicing genes, mirroring the results for flight evolution. Similar to previous studies of flight loss in various animal taxa, we observed consistently higher nonsynonymous-to-synonymous substitution ratios in mitochondrial genes of flightless lineages, indicative of relaxed selection in energy-related genes. While oxidative phosphorylation genes were not detected as being under selection with the origin of flight specifically, they were most often detected as being under positive selection in holometabolous (complete metamorphosis) insects as compared with other insect lineages. This study supports some convergence in gene-specific selection pressures associated with flight ability, and the exploratory analysis provided some new insights into gene categories potentially associated with the gain and loss of flight in insects.

Concepts: DNA, Evolution, Metabolism, Insect, Bat, Hymenoptera, Flying and gliding animals, Endopterygota

23

Recently, naturally occurring magnetite (Fe3O4) has emerged as a new material for sulfide control in sewers. However, unrefined magnetite could have high heavy metal contents (e.g. Cr, Zn, Ni, Sn, etc.) and the capacity to remove dissolved sulfide is reasonably limited due to relatively large particle sizes. To overcome the drawbacks of unrefined magnetite we used an electrochemical system with mild steel as sacrificial electrodes to in-situ generate high strength solutions of plate-like magnetite nanoparticles (MNP). MNP with a size range between 120 to 160 nm were electrochemically generated at 9.35±0.28 g Fe3O4-Fe/L, resulting in a Coulombic efficiency (CE) for iron oxidation of 93.5±2.8 %. The produced MNP were found to effectively reduce sulfide levels in sewage from 12.7±0.3 to 0.2±0.0 mg S/L at a sulfide-to-MNP ratio of 0.26 g S/g Fe3O4-Fe. Subsequently, MNP were continuously generated with polarity switching at stable cell voltage for 31 days at 4.53±0.35 g Fe3O4-Fe/L with a CE for iron oxidation of 92.4±7.2 %. The continuously produced MNP reduced sulfide at similar levels to around 0.2 mg S/L at a ratio of 0.28 g S/g Fe3O4-Fe.

Concepts: Iron, Hydrogen, Redox, Electrochemistry, Carbon, Zinc, Electrochemical cell, Electrolysis

1

Objective To compare initial brain computed tomography (CT) scans with follow-up CT scans at one year in children with congenital Zika syndrome, focusing on cerebral calcifications.Design Case series study.Setting Barão de Lucena Hospital, Pernambuco state, Brazil.Participants 37 children with probable or confirmed congenital Zika syndrome during the microcephaly outbreak in 2015 who underwent brain CT shortly after birth and at one year follow-up.Main outcome measure Differences in cerebral calcification patterns between initial and follow-up scans.Results 37 children were evaluated. All presented cerebral calcifications on the initial scan, predominantly at cortical-white matter junction. At follow-up the calcifications had diminished in number, size, or density, or a combination in 34 of the children (92%, 95% confidence interval 79% to 97%), were no longer visible in one child, and remained unchanged in two children. No child showed an increase in calcifications. The calcifications at the cortical-white matter junction which were no longer visible at follow-up occurred predominately in the parietal and occipital lobes. These imaging changes were not associated with any clear clinical improvements.Conclusion The detection of cerebral calcifications should not be considered a major criterion for late diagnosis of congenital Zika syndrome, nor should the absence of calcifications be used to exclude the diagnosis.

Concepts: Medical imaging, Tomographic reconstruction, Human brain, Cerebrum, Functional neuroimaging

1

Transanal total mesorectal excision (taTME) is an altogether different approach to rectal cancer surgery, and the effects of carbon dioxide (CO2) on this dissection remain poorly described.

Concepts: Oxygen, Carbon dioxide, Magnesium, Colorectal cancer, Carbon, Carbon monoxide, Total mesorectal excision, Carbon trioxide

0

Early life adversity remains a significant risk factor for the development of a host of negative behavioural and pathological outcomes in adulthood long after the stressor is over. Recent evidence indicates that these lasting effects of ELS may occur via alterations in the epigenetic landscape. Here, we review the main findings of the effects of early life adversity on DNA methylation, histone post-translational modification, and non-coding RNAs in the context of psychiatric disease in animal models and human cohorts. We specifically explore how early life adversity alters epigenetic patterns in both a global manner, and in specific candidate genes that play a role in relevant systems such as the hypothalamic-pituitary-adrenal axis, as well as neurotransmitter and neuroendocrine signalling. We also discuss how individual factors, such as genetics, sex, and age, as well as the type, and timing of early life adversity, can create differential susceptibility and significantly moderate outcomes. Although challenges remain in deciphering the complexity of how the early environment interacts with individual factors to determine epigenetic patterns, as well as how to translate these mechanistic findings into clinically relevant populations, the reviewed literature sheds light on the potential of the field to identify effective interventions for vulnerable individuals.

0

Although visceral leishmaniasis (VL) can affect immunocompromised patients, data from the human immunodeficiency virus (HIV) infection context are limited, and the characteristics of VL in other immunosuppression scenarios are not well defined. A retrospective review of all cases of VL in immunocompromised patients from January 1997 to December 2014 in two Spanish hospitals on the Mediterranean coast was performed. We included 18 transplant recipients (kidney: 7, liver: 4, lung: 3, heart: 2, and blood marrow: 2), 12 patients with other causes of immunosuppression (myasthenia gravis: 3 and rheumatoid arthritis: 2), and 73 VL HIV-positive patients. Fever was more common in transplant patients (94.4%) and patients with other types of immunosuppression (100%) than in HIV-positive individuals (73.3%). Hepatomegaly was less common in transplant recipients (27.8%) and patients with other types of immunosuppression (41.7%) compared with HIV-positive patients (69.9%) (P = 0.01; P = 0.001, respectively). Patients with other types of immunosuppression had a median leukocyte count of 1.5 × 10(9)/L, significantly lower than HIV-positive patients (2.5 × 10(9)/L) (P = 0.04). Serology was more commonly positive in nontransplant immunosuppressed individuals (75%) and transplant recipients (78.6%) than in HIV-patients (13.8%) (P < 0.001). Antimonial therapy was rarely used in transplant recipients (1.9%) and never in patients with other immunosuppressive conditions, whereas 34.2% of HIV-positive patients received it (P = 0.05 and P = 0.01, respectively). Mortality was 16.7% in both transplant recipients and patients with other immunosuppressive conditions and 15.1% in HIV-positive patients. The features of VL may be different in immunosuppressed patients, with more fever and less hepatomegaly and leukopenia than in HIV-infected patients.

Concepts: HIV, AIDS, Immune system, Cohort study, Blood, Opportunistic infection, Immunosuppressive drug, Immunodeficiency

0

Chagas disease results in the largest burden, in terms of disability-adjusted-life-years, of any parasitic disease in the Americas. Monitoring Chagas disease among migrants is critical to controlling its spread and to serving the needs of the migrant community. Therefore, we determined the prevalence and correlates of Chagas disease in regional and international migrant populations at the Mexico/Guatemala border. Data were collected as part of a larger study of human immunodeficiency virus (HIV) and migration. Participants were a sample of recent regional and international migrants who used an illicit substance or had recent problem drinking. Trypanosoma cruzi infection was classified as testing positive on two different enzyme-linked immunosorbent assays (ELISAs). Interviewer-administered surveys captured sociodemographics, migration history, Chagas disease knowledge, and access to care. We enrolled 389 recent migrants, and the prevalence of Chagas disease was 3.1%. Only 19% of the participants reported having ever heard of the disease and less than 1% had been previously tested. Trypanosoma cruzi-positive participants were more likely to have been born in a rural area or town than a city (92% yes versus 59% no, P = 0.02) and have recently lived in a house with a makeshift roof (33% yes versus 8% no, P < 0.01), walls (42% yes versus 13% no, P < 0.01), or floor (50% yes versus 21% no, P < 0.02), or cinderblock walls (92% yes versus 63% no, P = 0.04). With migration rapidly changing the distribution of Chagas disease, more work needs to be done to create targeted surveillance programs and provide access to affordable treatment among Latin American migrants.

Concepts: Immune system, Infectious disease, Population, Chagas disease, ELISA, Immigration, Trypanosoma, Trypanosoma cruzi

0

Diagnosing myocarditis is challenged by nonspecific clinical signs and symptoms and low accuracy of endomyocardial biopsy. Cardiac magnetic resonance imaging (CMR) provides both cardiac anatomy and tissue characterization in this setting, but the prognostic value of this method as a primary assessment tool in patients with suspected myocarditis remains limited.

Concepts: Spin, Nuclear magnetic resonance, Symptom, Magnetic resonance imaging, Medical diagnosis, Radiology, Ultrasound, Medical sign