Individual risk factors that modify the short-term effects of air pollution on mortality: a population-basedstudy of Chinese population

published_or_final_versionCommunity MedicineDoctoralDoctor of Philosoph

Elimination of bacteria from semen using a combination of density gradient centrifugation and swim-up

Background: To evaluate the efficiency of bacterial clearance of different sperm preparation procedure. Methods: A total of 46 semen samples were collected in this study, each semen sample was divided into four equal parts (0.5 mL each). The first part was prepared by density-gradient centrifugation (D-group), the second part was prepared by swim-up (S-group), the third part was treated with density-gradient centrifugation combined with swim-up (D+S-group), and the fourth group was the original raw semen group (O-group) regarded as the control. After each semen preparation procedure, the O-group and suspensions were inoculated and incubated for bacterial identification and colony counting. Results: Initially only 8.7% (4/46) of samples were bacteria free. After processing, the bacterial clearance rates were 23.8% for D-group, 57.4% for S-group and 97.8% for D+S-group (p < 0.001). Multiple bacterial strains were observed in 37 samples with 117 different bacterial strains in all identified in the original semen. 44.4% of the staphylococci and 89.7% of streptococci were not eliminated in D-group. In S-group, the corresponding rates were 24.4% and 35.9%. In D+S-group there were no remaining strains of staphylococci and only 2.6% of streptococci remained. After the combined procedure, the number of bacterial colonies fell dramatically after processing. Conclusion: The combined D+S protocol appears to be substantially more efficient than either method alone in eliminating bacteria from semen samples

The value of bronchodilator response in FEV1 and FeNO for differentiating between chronic respiratory diseases: an observational study

Abstract Background There is no uniform standard for a strongly positive bronchodilation test (BDT) result. In addition, the role of bronchodilator response in differentiating between asthma, chronic obstructive pulmonary disease (COPD), and asthma–COPD overlap (ACO) in patients with a positive BDT result is unclear. We explored a simplified standard of a strongly positive BDT result and whether bronchodilator response combined with fractional exhaled nitric oxide (FeNO) can differentiate between asthma, COPD, and ACO in patients with a positive BDT result. Methods Three standards of a strongly positive BDT result, which were, respectively, defined as post-bronchodilator forced expiratory volume in 1-s responses (ΔFEV1) increasing by at least 400 mL + 15% (standard I), 400 mL (standard II), or 15% (standard III), were analyzed in asthma, COPD, and ACO patients with a positive BDT result. Receiver operating characteristic curves were used to determine the optimal values of ΔFEV1 and FeNO. Finally, the accuracy of prediction was verified by a validation study. Results The rates of a strongly positive BDT result and the characteristics between standards I and II were consistent; however, those for standard III was different. ΔFEV1 ≥ 345 mL could predict ACO diagnosis in COPD patients with a positive BDT result (area under the curve [AUC]: 0.881; 95% confidence interval [CI] 0.83–0.94), with a sensitivity and specificity of 90.0% and 91.2%, respectively, in the validation study. When ΔFEV1 was < 315 mL combined with FeNO < 28.5 parts per billion, patients with a positive BDT result were more likely to have pure COPD (AUC: 0.774; 95% CI 0.72–0.83). Conclusion The simplified standard II can replace standard I. ΔFEV1 and FeNO are helpful in differentiating between asthma, COPD, and ACO in patients with a positive BDT result

Patients with Asian-type DEL can safely be transfused using RhD-positive blood

Red blood cells (RBCs) of the Asian-type DEL phenotype express few RhD proteins and are typed as serologic RhD-negative (D-) in routine testing. RhD-positive (D+) RBC transfusion for Asian-type DEL patients has been proposed but has not been generally adopted due to a lack of direct evidence regarding its safety and underlying mechanism. We performed a single-arm multicenter clinical trial to document the outcome of D+ RBC transfusion in Asian-type DEL patients; none of the recipients (0/42; 95% confidence interval, 0%-8.40%) developed alloanti-D after a median follow-up of 226 days. We conducted a large retrospective study to detect alloanti-D immunization in 4,045 serologic D- pregnant women throughout China; alloanti-D was found only in true D- individuals (2.63%, 79/3,009), but not in those with Asian-type DEL (0/1,032). We further retrospectively examined 127 serologic D- pregnant women who had developed alloanti-D and found none with Asian-type DEL (0/127). Finally, we analyzed RHD transcripts from Asian-type DEL erythroblasts and examined antigen epitopes expressed by various RHD transcripts in vitro, finding a low abundance of full-length RHD transcripts (0.18% of the total) expressing RhD antigens carrying the entire repertoire of epitopes, which could explain the immune tolerance against D+ RBCs. Our results provide multiple lines of evidence that individuals with Asian-type DEL cannot produce alloanti-D when exposed to D+ RBCs following transfusion or pregnancy. Therefore, we recommend considering D+ RBC transfusion and discontinuing anti-D prophylaxis in Asian-type DEL patients, including pregnant women. This clinical trial is registered at www.clinicaltrials.gov as NCT03727230