Pitfalls in the measurement of plasma osmolality pertinent to research in vasopressin and water metabolism

The reliability of measurements of plasma osmolality is known to be biased by technical artifacts, such as the anticoagulant and the osmometric technique used; the resulting measurement errors therefore may cause errors in interpretation of data. In assessing the potential biasing influence of procedural variables, we found that the temperature at which fresh plasma samples were stored, the duration of storage, and the freezing and thawing of samples appeared to significantly (P < 0.01) affect osmolality values around the narrow physiological range. These factors should be considered in the interpretation of studies on the osmoregulation of vasopressin secretion. In particular, the results suggest that data obtained for any but fresh samples, whether frozen-thawed samples or samples stored at room temperature, are unreliable

Using a Smartphone App and Coaching Group Sessions to Promote Residents' Reflection in the Workplace

Item does not contain fulltextPROBLEM: Reflecting on workplace-based experiences is necessary for professional development. However, residents need support to raise their awareness of valuable moments for learning and to thoughtfully analyze those learning moments afterwards. APPROACH: From October to December 2012, the authors held a multidisciplinary six-week postgraduate training module focused on general competencies. Residents were randomly assigned to one of four conditions with varying degrees of reflection support; they were offered (1) a smartphone app, (2) coaching group sessions, (3) a combination of both, or (4) neither type of support. The app allowed participants to capture in real time learning moments as a text note, audio recording, picture, or video. Coaching sessions held every two weeks aimed to deepen participants' reflection on captured learning moments. Questionnaire responses and reflection data were compared between conditions to assess the effects of the app and coaching sessions on intensity and frequency of reflection. OUTCOMES: Sixty-four residents participated. App users reflected more often, captured more learning moments, and reported greater learning progress than nonapp users. Participants who attended coaching sessions were more alert to learning moments and pursued more follow-up learning activities to improve on the general competencies. Those who received both types of support were most alert to these learning moments. NEXT STEPS: A simple mobile app for capturing learning moments shows promise as a tool to support workplace-based learning, especially when combined with coaching sessions. Future research should evaluate these tools on a broader scale and in conjunction with residents' and students' personal digital portfolios

Changes in plasma vasopressin concentration and plasma osmolality in relation to age and time of day in the male Wistar rat

The influence of age on several parameters related to water balance was studied in Wistar rats. Plasma AVP concentration and plasma osmolality were increased at midday in 21-month-old rats as compared with 3- and 4-month-old rats. Daily water intake per 100 g body weight was reduced in 14- and 21-month-old rats as compared with 3- and 4-month-old rats, but total water intake was unaltered. These results suggest that there is a change in water balance in Wistar rats with age. In order to obtain information about the influence of age on daily fluctuations in plasma AVP concentration and osmolality these parameters were determined in 4-month-old Wistar rats sacrificed at 2 h intervals during the day and in 20- and 31-month-old rats sacrificed at 8 h intervals. Plasma AVP concentrations were low during the light period and high during the dark period in 4-month-old rats. The relationship between plasma osmolality and plasma AVP concentration was dependent on the time of day in 4-month-old-rats, Plasma AVP concentrations were higher at 16.00 than at 08.00 and 24.00 in 20-month-old rats, and higher at 24.00 than at 08.00 and 16.00 in 31-month-old rats. In contrast to the plasma AVP concentration during the light period, the average daily AVP concentration (average of plasma AVP concentrations at 08.00, 16.00 and 24.00) was increased in 31-month-old rats only. The relationship between plasma osmolality and plasma AVP concentration was not age-related. The results of the present study suggest that there is a circadian rhythm of plasma AVP concentration in Wistar rats which is age-related but which does not fully correlate with plasma osmolality

Effectiveness of collagen supplementation on pain scores in healthy individuals with self-reported knee pain: a randomized controlled trial

The purpose of this study was to examine the effects of 12 weeks collagen peptide (CP) supplementation on knee pain and function in individuals with self-reported knee pain. Healthy physically active individuals (n = 167; aged 63 [interquartile range = 56–68] years) with self-reported knee pain received 10 g/day of CP or placebo for 12 weeks. Knee pain and function were measured with the Visual Analog Scale (VAS), the Lysholm questionnaire, and the Knee injury and Osteoarthritis Outcome Score (KOOS). Furthermore, we assessed changes in inflammatory, cartilage, and bone (bio)markers. Measurements were conducted at baseline and after 12 weeks of supplementation. Baseline VAS did not differ between CP and placebo (4.7 [2.5–6.1] vs. 4.7 [2.8–6.2], p = 0.50), whereas a similar decrease in VAS was observed after supplementation (−1.6 ± 2.4 vs. −1.9 ± 2.6, p = 0.42). The KOOS and Lysholm scores increased after supplementation in both groups (p values 0.05). A reduced knee pain and improved knee function were observed following supplementation, but changes were similar between groups. This suggests that CP supplementation over a 12-week period does not reduce knee pain in healthy, active, middle-aged to elderly individuals. Novelty CP supplementation over a 12-week period does not reduce knee pain in healthy, active, middle-aged to elderly individuals. CP supplementation over a 12-week period does not impact on inflammatory, cartilage, and bone (bio)markers in healthy, active, middle-aged to elderly individuals.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Effect of using the HEART score in patients with chest pain in the emergency department: A Stepped-wedge, cluster randomized trial

Background: The HEART (History, Electrocardiogram, Age, Risk factors, and initial Troponin) score is an easy-to-apply instrument to stratify patients with chest pain according to their short-term risk for major adverse cardiac events (MACEs), but its effect on daily practice is unknown. Objective: To measure the effect of use of the HEART score on patient outcomes and use of health care resources. Design: Stepped-wedge, cluster randomized trial. (Clinical Trials.gov: NCT01756846) Setting: Emergency departments in 9 Dutch hospitals. Patients: Unselected patients with chest pain presenting at emergency departments in 2013 and 2014. Intervention: All hospitals started with usual care. Every 6 weeks, 1 hospital was randomly assigned to switch to "HEART care," during which physicians calculated the HEART score to guide patient management. Measurements: For safety, a noninferiority margin of a 3.0% absolute increase in MACEs within 6 weeks was set. Other outcomes included use of health care resources, quality of life, and cost-effectiveness. Results: A total of 3648 patients were included (1827 receiving usual care and 1821 receiving HEART care). Six-week incidence of MACEs during HEART care was 1.3% lower than during usual care (upper limit of the 1-sided 95% CI, 2.1% [within the noninferiority margin of 3.0%]). In low-risk patients, incidence of MACEs was 2.0% (95% CI, 1.2% to 3.3%). No statistically significant differences in early discharge, readmissions, recurrent emergency department visits, outpatient visits, or visits to general practitioners were observed. Limitation: Physicians were hesitant to refrain from admission and diagnostic tests in patients classified as low risk by the HEART score. Conclusion: Using the HEART score during initial assessment of patients with chest pain is safe, but the effect on health care resources is limited, possibly due to nonadherence to management recommendations