No abstract

Rat mortality and contractile responses of isolated tracheas to compound 48/80 from rats made diabetic 4 days before by a single intravenous injection of alloxan and from diabetic rats that had been treated with insulin 6 h before were compared with control animals. Diabetic animals and tracheal segments from diabetic rats were significantly less responsive to compound 48/80 than control and insulin-treated diabetic animals. On the other hand, diabetic animals have a lower quantity of peritoneal mast cells than control rats, and insulin restored the normal quantity of cells in diabetic animals. These data indicate that diabetes elicits an hyposensitivity to compound 48/80, possibly related to a diabetes-induced decrease in the mast cell count.Key words: diabetes mellitus, bronchial hyposensitivity, compound 48/80, mast cell.

Background: Reported risk of bleeding complications after central catheter access in patients with thrombocytopenia is highly variable. Current guidelines recommend routine prophylactic platelet (PLT) transfusion before central venous catheter placement in patients with severe thrombocytopenia. Nevertheless, the strength of such recommendations is weak and supported by observational studies including few patients with very low PLT counts (<20 × 10 9 /L). This study aims to assess the risk of bleeding complications related to using or not using prophylactic PLT transfusion before ultrasound-guided central venous access in patients with very low PLT counts. Methods:This was a retrospective cohort study of patients with very low PLT counts (<20 × 10 9 /L) subjected to ultrasound-guided central venous catheterization between January 2011 and November 2019 in a university hospital. Bleeding complications were graded according to the Common Terminology Criteria for Adverse Events. A multivariate logistic regression was conducted to assess the risk of major and minor bleeding complications comparing patients who did or did not receive prophylactic PLT transfusion for the procedure. Multiple imputation by chained equations was used to handle missing data. A two-tailed p < 0.05 was considered statistically significant.Results: Among 221 patients with very low PLT counts, 72 received prophylactic PLT transfusions while 149 did not. Baseline characteristics were similar between transfused and nontransfused patients. No major bleeding events were identified, while minor bleeding events were recognized in 35.7% of patients. Multivariate logistic regression analysis showed no significant differences in bleeding complications between patients who received prophylactic PLT transfusions and those who did not (odds ratio 0.83, 95% confidence interval 0.45-1.55, p = 0.567). Additional complete case and sensitivity analyses yielded results similar to those of the main analysis. Conclusions:In this single-center retrospective cohort study of ultrasound-guided central venous access in patients with very low PLT counts, no major bleeding was identified, and prophylactic PLT transfusions did not significantly decrease minor bleeding events.

BackgroundTracheobronchial injury is one of the least common injuries in the scenario of blunt chest trauma. However, around 81% of patients with airway injury die immediately or before arriving at the emergency department due to tension pneumothorax. It presents with non-specific signs and symptoms challenging prompt diagnosis.Case presentationA 15-year-old adolescent who was riding a bicycle suffered an accident when he fell down a cliff, approximately 5 m deep. Upon admission to the emergency department, he presented with signs of respiratory distress. The airway was secured and a thoracoabdominal angiography was performed. The image reported pneumomediastinum, a small right pneumothorax, areas of pulmonary contusion, and an image of loss of continuity in the anterior superior wall of the right main bronchus highly suggestive of bronchial rupture. The bronchial lesion was then confirmed by fiberoptic bronchoscopy. Taking into account the patient’s characteristics, conservative management was chosen, and the patient was transferred to the intensive care unit (ICU) where protective tracheal intubation was performed.ConclusionsA delay in diagnosis increases the rate of complications, mainly infectious complications and the formation of granulation tissue that could potentially obstruct the airway, impacting the patient’s outcome. The first step in the management of these patients is securing the airway, which should be done immediately. The gold standard for the diagnosis and characterization of airway injuries is bronchoscopy as it is the most effective tool to assess topography, extent, and depth of the lesion.

Background: A strong association between the proportion of Native American ancestry and the risk of gallbladder cancer (GBC) has been reported in observational studies. Chileans show the highest incidence of GBC worldwide, and the Mapuche are the largest Native American people in Chile. We set out to investigate the causal association between Native American Mapuche ancestry and GBC risk, and the possible mediating effects of gallstone disease and body mass index (BMI) on this association. Methods: Markers of Mapuche ancestry were selected based on the informativeness for assignment measure and then used as instrumental variables in two-sample mendelian randomization (MR) analyses and complementary sensitivity analyses. Results: We found evidence of a causal effect of Mapuche ancestry on GBC risk (inverse variance-weighted (IVW) risk increase of 0.8% for every 1% increase in Mapuche ancestry proportion, 95% CI 0.4% to 1.2%, p = 6.6×10 -5 ). Mapuche ancestry was also causally linked to gallstone disease (IVW risk increase of 3.6% per 1% increase in Mapuche proportion, 95% CI 3.1% to 4.0%, p = 1.0×10 -59 ), suggesting a mediating effect of gallstones in the relationship between Mapuche ancestry and GBC. In contrast, the proportion of Mapuche ancestry showed a negative causal effect on BMI (IVW estimate -0.006 kg/m 2 per 1% increase in Mapuche proportion, 95% CI -0.009 to -0.003, p = 4.4×10 -5 ). Conclusions: The results presented here may have significant implications for GBC prevention and are important for future admixture mapping studies. Given that the association between Mapuche ancestry and GBC risk previously noted in observational studies appears to be causal, primary and secondary prevention strategies that take into account the individual proportion of Mapuche ancestry could be particularly efficient.