No evidence of a genetic polymorphism in the oxidative metabolism of midazolam

The benzodiazepine midazolam is rapidly eliminated by oxidative metabolism. In young healthy volunteers elimination half-life (t1/2) is about 2.4 hours. A recent study showed a prolonged t1/2 from 8 to 22 hours in 6.5% of surgical patients, and a genetic polymorphism of midazolam's metabolism has been suggested. Therefore, we measured in 168 surgical patients the elimination of midazolam and its major hydroxylated metabolite (alpha-OH-midazolam) in blood and urine. Co-medication, disease status, smoking habits and alcohol intake were recorded; normal liver and kidney functions were assessed by routine laboratory tests. Midazolam was administered intravenously (0.1 to 0.2 mg/kg) for the induction of anaesthesia. Blood was drawn 1.5, 3, 4.5 and 6 hours after application and urine was collected for 6 hours. Plasma protein binding of midazolam was determined by equilibrium dialysis. Midazolam and alpha-OH-midazolam were measured in plasma by specific gas-liquid chromatography and in urine by high performance liquid chromatography. Data for the dose-corrected area under plasma-level curve of midazolam (AUC-midazolam/dose: 1.23 +/- 961 x 10(5) h/ml; mean +/- SD) and for the metabolic plasma ratio (AUC of alpha-OH-midazolam/AUC-midazolam: 0.52 +/- 0.28) demonstrated a log-normal distribution. Likewise, the percentage of the unbound fraction of midazolam in plasma (5.0 +/- 2.4%), urinary excretion of alpha-OH-midazolam (55.9 +/- 22.7% of dose) and the values for t1/2 (2.9 +/- 1.1 hours) did indicate a unimodal distribution. Age, comedication and smoking habits did not affect the disposition of midazolam. However, patients with regular intake of alcohol had a higher (p less than 0.05) metabolic ratio. Only in 3 patients could a prolonged t1/2 of midazolam from 7.5 to 10.2 hours be detected, but plasma levels and urinary excretion of alpha-OH-midazolam in those individuals were found to be normal. Therefore it is very unlikely that the oxidative metabolism of midazolam exhibits a genetic polymorphism.     

Effects of Continuous Intake of Rosemary Extracts on Mental Health in Working Generation Healthy Japanese Men: Post-Hoc Testing of a Randomized Controlled Trial

We previously performed a 4 week interventional trial that suggested that continuous intake of rosemary extract improves the mood states, fatigue, and cognitive function of working generation healthy adult Japanese men. However, the severity of depression in participants in our previous study was relatively mild. Therefore, in the present study, a post-hoc analysis of our previous study was conducted, limited to participants whose total mood disturbance (TMD) scores, which indicate greater mood disturbance, were above the median at baseline, to evaluate whether rosemary extract was effective for individuals with poor mental health. Following the intervention, the scores of TMD and “Confusion-Bewilderment” were significantly decreased (both p < 0.05), and scores of “Vigor-Activity” were significantly increased in the rosemary group (n = 8) compared with those in the control group (n = 13; p < 0.01). When comparing the scores from pre- and post-intervention, significant improvements in “Tension-Anxiety”, “Vigor-Activity”, “Fatigue on awakening”, “Daytime sleepiness”, and “Psychomotor speed” were observed in the rosemary group only (all p < 0.05). Based on these results, it was expected that rosemary extracts were effective for improving the mental energy and sleep quality of work-age men with poor mental health.     

Flow Preconditioning of Endothelial Cells on Collagen‐Immobilized Silicone Fibers Enhances Cell Retention and Antithrombotic Function

Stability and antithrombotic functionality of endothelial cells on silicone hollow fibers (SiHFs) are critical in the development of biohybrid artificial lungs. Here we aimed to enhance endothelial cell retention and anti‐thrombotic function by low (12 dyn/cm², 24 h) fluid shear stress (“flow”) preconditioning of endothelial cells seeded on collagen‐immobilized SiHFs. The response of endothelial cells without preconditioning (48 h static culture) and with preconditioning (24 h static culture followed by 24 h flow preconditioning) on hollow fibers to high fluid shear stress (30 dyn/cm², 1 h) was assessed in a parallel‐plate flow chamber. Finite element (FE) modeling was used to simulate shear stress within the flow chamber. We found that collagen immobilization on hollow fibers using carbodiimide bonds provided sufficient stability to high shear stress. Flow preconditioning for 24 h before treatment with high shear stress for 1 h on collagen‐immobilized hollow fibers increased cell retention (1.3‐fold). The FE model showed that cell flattening due to flow preconditioning reduced maximum shear stress on cells by 32%. Flow preconditioning prior to exposure to high fluid shear stress enhanced the production of nitric oxide (1.3‐fold) and prostaglandin I₂ (1.2‐fold). In conclusion, flow preconditioning of endothelial cells on collagen‐immobilized SiHFs enhanced cell retention and antithrombotic function, which could significantly improve current biohybrid artificial lungs.     

Preoperative Cerebrovascular Evaluation in Patients With Infective Endocarditis

Approximately 12% to 40% of infective endocarditis patients experience cerebrovascular complications. One of the major clinical challenges in cerebrovascular medicine is management of infective endocarditis patients with cerebrovascular complications who require valve operations. Cerebrovascular specialists are often summoned to address appropriate preoperative brain imaging, timing of surgery, and estimation of the risk of perioperative cerebral embolization and hemorrhage. This article addresses these issues based on the available evidence.     

Composition of mineralizing incisor enamel in cystic fibrosis transmembrane conductance regulator‐deficient mice

Formation of crystals in the enamel space releases protons that need to be buffered to sustain mineral accretion. We hypothesized that apical cystic fibrosis transmembrane conductance regulator (CFTR) in maturation ameloblasts transduces chloride into forming enamel as a critical step to secrete bicarbonates. We tested this by determining the calcium, chloride, and fluoride levels in developing enamel of Cftr‐null mice by quantitative electron probe microanalysis. Maturation‐stage enamel from Cftr‐null mice contained less chloride and calcium than did wild‐type enamel, was more acidic when stained with pH dyes ex vivo, and formed no fluorescent modulation bands after in vivo injection of the mice with calcein. To acidify the enamel further we exposed Cftr‐null mice to fluoride in drinking water to stimulate proton release during formation of hypermineralized lines. In Cftr‐deficient mice, fluoride further lowered enamel calcium without further reducing chloride levels. The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.     

Recruitment in pediatric clinical research was influenced by study characteristics and pediatricians' perceptions: a multicenter survey

ObjectivesThe aim of this survey was to quantify refusal rates and identify factors of refusal pertaining to studies and recruiting pediatricians in the research recruitment process.Study Design and SettingWe performed a cross-sectional survey on all clinical studies conducted in six pediatric Clinical Investigation Centers in France over an 18-month period. Data were retrieved using a data collection form for the characteristics of each of the studies included in the survey and a questionnaire addressed to recruiting pediatricians. Multilevel models were used for the statistical analysis.ResultsOverall, 145 pediatricians approached the families of 999 children and adolescents for participation in 44 studies. In the 36 of the 44 studies that enrolled subjects, median refusal rate was 12.5% (Q1–Q3, 0–28%). Lower refusal rates were associated with therapeutic drug use as the focus of the study [odds ratio (OR), 0.51; 95% CI: 0.25, 1.05], additional hospital stays required for the study (OR, 0.53; 95% CI: 0.28, 0.99), longer duration of the inclusion visit (OR, 0.93/10 min; 95% CI: 0.87, 1), and recruitment by a pediatrician with university teaching responsibilities (OR, 0.26; 95% CI: 0.10, 0.68). Refusal rate was higher when the recruiting pediatrician perceived the study as generating heavy practical burden for the subject and/or its family (OR, 1.3; 95% CI: 1.17, 1.45).ConclusionRefusal to participate in clinical research was low and was influenced by factors associated to the objectives and conduct of the studies and factors related to the characteristics and perceptions of the recruiting pediatricians.