Effect of Smoking History on 30-Day Morbidity Following Bariatric Surgery

INTRODUCTION

Smoking and postoperative complications are well documented across surgical specialties. Preoperative smoking cessation is frequently recommended by surgeons. In this study, we assessed to what degree documented smoking history increased a patient's risk of postoperative complications.

METHODS

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database for the years 2015-2018 was used. Patients were included if they underwent primary sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (LRYGB). Patients with a documented smoking history were assigned to the "SH" cohort and patients without smoking history were assigned to the "NSH" cohort. Patients without documentation regarding smoking history, missing variables, younger than 18, with prior surgery, or lost to follow-up were excluded. 30-day morbidity and mortality data were assessed. Multiple logistic regression analysis was made based on all available patient characteristics and perioperative factors, continuous variables were analyzed using Student's t-test and categorical variables were compared using the chi-square test.

RESULTS

After evaluation of 760,076 patients on the MBSAQIP database, 650,930 patients underwent non-revisional bariatric surgery, including 466,270 SG and 184,660 LRYGB. Of the total patients included in the study, 44,606 patients were assigned to the SH cohort and 479,601 were assigned to the NSH cohort. 4628 of patients did not have documented smoking status. Within 30 days SH patients had higher rates of readmission (4.2% vs 3.7%, P < .0001), reoperation (1.3% vs 1.1%, P < .0001), unplanned intubation (.2% vs .1%, P = .0212), and unplanned ICU admission (.7% vs .0.6%, P = .0022).

CONCLUSION

SH patients undergoing bariatric surgery were at significantly increased risk of readmission and reoperation within 30 days of procedure. In addition, SH patients were more likely to have unplanned intubation and unplanned ICU admission. Given the higher rates of complications in smoking patients, this study would suggest that preoperative smoking cessation in patients prior to primary bariatric surgery might be beneficial. Further study is warranted to compare short-term cessation vs long-term cessation preoperatively, which was not assessed in our study.

Machine-guided design of synthetic cell type-specific cis-regulatory elements

Cis-regulatory elements (CREs) control gene expression, orchestrating tissue identity, developmental timing, and stimulus responses, which collectively define the thousands of unique cell types in the body. While there is great potential for strategically incorporating CREs in therapeutic or biotechnology applications that require tissue specificity, there is no guarantee that an optimal CRE for an intended purpose has arisen naturally through evolution. Here, we present a platform to engineer and validate synthetic CREs capable of driving gene expression with programmed cell type specificity. We leverage innovations in deep neural network modeling of CRE activity across three cell types, efficient in silico optimization, and massively parallel reporter assays (MPRAs) to design and empirically test thousands of CREs. Through in vitro and in vivo validation, we show that synthetic sequences outperform natural sequences from the human genome in driving cell type-specific expression. Synthetic sequences leverage unique sequence syntax to promote activity in the on-target cell type and simultaneously reduce activity in off-target cells. Together, we provide a generalizable framework to prospectively engineer CREs and demonstrate the required literacy to write regulatory code that is fit-for-purpose in vivo across vertebrates.

Complexity of Brain Dynamics as a Correlate of Consciousness in Anaesthetized Monkeys

The use of anaesthesia is a fundamental tool in the investigation of consciousness. Anesthesia procedures allow to investigate different states of consciousness from sedation to deep anesthesia within controlled scenarios. In this study we use information quantifiers to measure the complexity of electrocorticogram recordings in monkeys. We apply these metrics to compare different stages of general anesthesia for evaluating consciousness in several anesthesia protocols. We find that the complexity of brain activity can be used as a correlate of consciousness. For two of the anaesthetics used, propofol and medetomidine, we find that the anaesthetised state is accompanied by a reduction in the complexity of brain activity. On the other hand we observe that use of ketamine produces an increase in complexity measurements. We relate this observation with increase activity within certain brain regions associated with the ketamine used doses. Our measurements indicate that complexity of brain activity is a good indicator for a general evaluation of different levels of consciousness awareness, both in anesthetized and non anesthetizes states.

In silico prediction of B and T cell epitopes of infectious salmon anemia virus proteins and molecular modeling of T cell epitopes to salmon major histocompatibility complex (MHC) class I

Infectious salmon anemia (ISA) can be devastating in farmed Atlantic salmon (Salmo salar). The disease can evolve into epidemics if it is not contained and controlled. ISA epidemics were seen in Norway in the early 1990s and Chile in 2007-2009. Consequently, there is an urgent need to develop a vaccine to prevent or treat the infection. In this study, an immunoinformatic approach was employed to predict 32 lineal B-cell epitopes based on antigenicity and surface accessibility prediction for ISAV fusion (F), hemagglutinin-esterase (HE), and matrix (M) proteins. On the other hand, twelve conformational B-cell epitopes were also predicted. We further identified six antigenic cytotoxic T lymphocyte (CTL) epitopes and investigated the binding interactions with five salmon MHC-I proteins after docking the peptides to the binding groove of the MHC-I proteins. Our results showed that all the predicted epitopes could bind to salmon MHC-I with high negative ΔG values with medium to high binding affinities. Hence, the predicted epitopes have a high potential of being recognized by Atlantic salmon MHC-I to elicit a CD8⁺ T cell response in salmon. The predicted and analyzed B and T cell antigenic epitopes in this work might present an initial set of peptides for future vaccine development against ISAV. The ability to model and predict these interactions will ultimately lead to the ability to predict potential binding for MHCs and epitopes that were not studied previously. As current knowledge of salmon MHC specificity is limited, studying and modeling interactions in the peptide/MHC complex is a key to resolving unknown epitope specificity.

Merkel cell carcinoma and Merkel cell polyomavirus: a systematic review and meta-analysis

Several observational studies have assessed the correlation between Merkel cell carcinoma and Merkel cell polyomavirus with variable results. The objective of this systematic review was to determine whether there is a correlation between Merkel cell carcinoma and Merkel cell polyomavirus. Studies assessing the relationship between Merkel cell carcinoma and Merkel cell polyomavirus from January 2008 to August 2014 were pooled from Medline, Embase, PubMed, Cochrane Database of Systemic Reviews and Google Scholar. From each study we collected the first author's last name, publication year, country of origin, type of study design, characteristics of participants, possible variables incorporated into the multivariable analyses and the risk ratio (RR) for Merkel cell carcinoma associated with Merkel cell polyomavirus combined with the corresponding 95% confidence interval (CI). Methodological assessment of the study was evaluated using the Newcastle-Ottawa scale. Crude RR was calculated from the data provided in each article. Meta-analyses for the global RR and for the proportion of positives in both case and control samples were performed. In addition, in order to explore the sources of heterogeneity among the studies, meta-regression and sensitivity analyses are also provided. A total of 22 studies were identified for the analysis. The pooled RR from random-effects analysis was determined to be 6.32 (95% CI, 4.02-9.93). Global proportions of positive samples were 0.79 (95% CI, 0.72-0.84) and 0.12 (95% CI, 0.08-0.19) in the case and control groups, respectively. The findings support the association between Merkel cell carcinoma and Merkel cell polyomavirus. However, a non-negligible percentage of positive results have been identified in controls. Some caution must be taken in the interpretation of these results because heterogeneity between studies was found.

Isolation and characterization of biologically active murine interleukin-6 produced in Escherichia coli

Interleukin-6 (IL-6) is a multi-functional cytokine produced and secreted by several different cell types, including those of the immune system. A cDNA coding for the mature murine IL-6 (mIL-6), which extends from amino acid (aa) 25 through 211, was cloned into a prokaryotic vector and then expressed in Escherichia coli. The recombinant mIL-6 (remIL-6) was isolated from bacterial inclusion bodies by solubilization in 4 M guanidine hydrochloride followed by gel-filtration chromatography. The protein was refolded to an active conformation by dialysis against 25 mM Na. acetate pH 5.5. A final step of purification and concentration on a cation exchange resin yielded pure and biologically active remIL-6. The purified preparation had the expected aa composition, as confirmed by aa analysis and pI of 7.0-7.1. The biological activity of the recombinant protein was measured in two systems; a proliferation assay employing 7TD1 cells, and a fibrinogen biosynthesis assay employing primary rat hepatocytes. Both assay systems demonstrated that the remIL-6 was active in the range of 10(8) units/mg, which is similar to that estimated for native cytokine. Antibodies raised in rabbits against remIL-6 neutralized the biological activity of both recombinant and native IL-6.

Sulfatide role in the sodium pump

Sodium efflux was studied in 22Na-loaded red blood cells in the presence of arylsulfatase, an enzyme that specifically hydrolyzes sulfatide. Sodium efflux was inhibited in proportion to the amount of arylsulfatase present. Maximum inhibition was almost as high as the efflux obtained in medium with K+ absent. At maximum inhibition 83.2% of the sulfatide content of the fragmented red blood cell membranes was hydrolyzed and ouabain-sensitive (Na+ + K+)-ATPase activity was inhibited by 100%. Sodium efflux, sulfatide content, and (Na+ + K+)-ATPase activity were unaffected with arylsulfatase in the presence of a high concentration of sulfatide. These results indicate that sulfatide plays a specific role in sodium and potassium ion transport. They also suggest that most sulfatide is localized externally in the red blood cell membrane.