Allergen bronchoprovocation: correlation between FEV1 maximal percent fall and area under the FEV1 curve and impact of allergen on recovery.

BACKGROUND: House dust mite (HDM) induces greater responses than other allergens during allergen bronchoprovocation (ABP) testing. The two standardized methods for reporting results of ABP tests are the maximal percent fall in forced expiratory volume in one second (FEV1, max; %) and the area under the FEV1 vs time curve (AUC; %FEV1 x min). The relationship between these methods has not been previously investigated. AIMS: We aimed to measure the correlation between FEV1, max and AUC during the early asthmatic response (EAR) and the late asthmatic response (LAR), and to determine if the EAR recovery period for HDM would be longer than other allergens (cat, grass, horse, and ragweed). METHODS: We retrospectively calculated the AUC and correlation between FEV1, max and AUC during the EAR(0-2 h) and LAR(3-7 h) for each allergen. We compared EAR(0-3 h) and LAR(3-7 h) FEV1, max, AUC and absolute difference in FEV1, max to the most recovered FEV1 (FEV1, min). We performed pairwise comparisons of correlation and slope values using Fischer's r to z transformation and t-tests, respectively. AUC and absolute differences in FEV1, max and FEV1, min were compared using a one-way ANOVA test, followed by a post-hoc Scheffe test. RESULTS: Correlation between the FEV1, max and AUC during the EAR(0-2 h) (n = 221) was 0.807, and was 0.798 during the LAR(3-7 h) (n = 157 of 221), (difference p = 0.408). The EAR(0-3 h) AUC and FEV1, max did differ between allergens (both p < 0.0001) but the LAR(3-7 h) AUC and FEV1, max did not (p = 0.548 and 0.824, respectively). HDM did not have a larger AUC or FEV1, max, than all other allergens during the EAR(0-3 h) or the LAR(3-7 h). The absolute difference between the FEV1, max and FEV1, min during the EAR(0-3 h) did not differ between allergens (p = 0.180). CONCLUSION: The FEV1, max and AUC for both the EAR(0-2 h) and LAR(3-7 h) had excellent correlation, with no significant difference. Thus, significant bronchoconstriction will likely result in a longer recovery period. There was no evidence of delayed EAR(0-3 h) recovery following HDM challenges, so HDM did not induce a larger response compared to all the other allergens examined. REGISTRATION: Not registered. This is not a clinical trial. (This study is a retrospective analysis of data collected during several registered trials.).

Duration of Pre-Operative Antibiotic Treatment and Culture Results in Patients With Infective Endocarditis.

BACKGROUND: Bacterial growth in cultures of resected heart valves of patients with infective endocarditis (IE) is influenced by pre-operative antibiotic treatment (preop-AT). OBJECTIVES: This study sought to evaluate the time dependency of valve culture results (positive valve culture [PVC] vs. negative valve culture) on preop-AT. METHODS: A total of 352 IE episodes in 344 adult patients of our tertiary referral hospital were retrospectively investigated (2005 to 2016). The primary endpoint was PVC results. The study used a logistic additive model adjusted for bacterial species, the McCabe-Jackson classification, and the existence of foreign valve material as covariables. RESULTS: The 231 included IE cases (187 [81%] men, median age 62 years, 153 [66%] native valves) comprised 58 (25%) PVC results and 173 (75%) negative valve culture results. A multivariable analysis adjusted for bacterial species, McCabe-Jackson classification, and valve type resulted in odds ratios for PVC of 6.35 (95% confidence interval [CI]: 1.94 to 20.78; p = 0.002) and 3.93 (95% CI: 1.57 to 9.84; p = 0.003) for Enterococcus spp. and Staphylococcus spp., respectively. Model-based odds ratios for PVC risk reduction in 2-day intervals of preop-AT ranged from 0.64 (95% CI: 0.61 to 0.68) at day 7 to 0.74 (95% CI: 0.70 to 0.78) at day 13 and 0.98 (95% CI: 0.93 to 1.02) at day 21. CONCLUSIONS: In IE cases treated with valve surgery, Staphylococcus aureus and Enterococcus spp. were associated with valve culture growth. After 7 days of antibiotic treatment, the additional effect of preop-AT on valve culture results per 2-day interval was minor. Antibiotic treatment beyond 21 days had no influence on culture results.

Cochlear function in mice following inhalation of brevetoxin-3.

Brevetoxin-3 was shown previously to adversely affect central auditory function in goldfish. The present study evaluated the effects of exposure to this agent on cochlear function in mice using the 2f(1)-f(2) distortion-product otoacoustic emission (DPOAE). Towards this end, inbred CBA/CaJ mice were exposed to a relatively high concentration of brevetoxin-3 (approximately=400 microg/m(3)) by nose-only inhalation for a 2-h period. Further, a subset of these mice received a second exposure a day later that lasted for an additional 4 h. Mice exposed only once for 2 h did not exhibit any notable cochlear effects. Similarly, mice exposed two times, for a cumulative dose of 6 h, exhibited essentially no change in DPOAE levels.