Long-term stability of endogenous B-type natriuretic peptide after storage at -20 degrees C or -80 degrees C

BACKGROUND: B-type natriuretic peptide (BNP) is a biomarker used in the investigation of heart failure and other cardiovascular diseases. Our aim was to analyze the degradation of BNP in plasma samples kept at -20 degrees C or at -80 degrees C after 3 months or 1 year of storage. METHODS: Using a Biosite assay-Triage BNP test, we evaluated 20 subjects with plasma BNP concentrations ranging from normal to high. Plasma aliquots were separated in five eppendorfs, one for immediate measurement after centrifugation, two for storage at -20 degrees C and two at -80 degrees C. We measured BNP after 3 months and 1 year. The significance level was set at p<0.05 (one-tailed test). RESULTS: There was a significant decrease of 1% per month in BNP concentration. However, there was a significant interaction between time and group (high vs. low BNP). Low BNP values did not change over time, while high BNP decreased by 2% per month. The decrease over time did not depend on the storage temperature. CONCLUSIONS: The storage of the samples at -20 degrees C or at -80 degrees C did not prevent BNP degradation, especially for high BNP values. For low BNP values, we did not observe a significant decay at either 3 months or 1 year. These results are valid for the Biosite assay-Triage BNP test.     

The spectrum of computerized tomography (CT) findings in central nervous system (CNS) infection due to Cryptococcus neoformans var. gattii in immunocompetent children

Cranial CT scans of eleven immunocompetent children with central nervous system (CNS) infection due to Cryptococcus neoformans var. gattii were retrospectively reviewed. These children had an average age of 8.8 years and positive culture for C. n. var. gattii in cerebrospinal fluid. The most common signs and symptoms were headache, fever, nuchal rigidity, nausea and vomiting. No normal cranial CT was detected in any patient. Hypodense nodules were observed in all patients. The remaining scan abnormalities were as follows: nine had diffuse atrophy, six had hydrocephalus, and five had hydrocephalus coexistent with diffuse atrophy.     

To participate or not participate in unprofessional behavior – Is that the question?

Introduction: Medical education provides students with abundant learning opportunities, each of which is embodied with messages concerning what is expected from students. This paper analyses students? exposure to instances of unprofessional behavior, investigating whether they judge such behavior to be unprofessional and whether they also participate in unprofessional behavior.

Methods: The survey developed in the Pritzker School of Medicine at the University of Chicago was the basis of this questionnaire that was answered by 276 students from two medical schools in Brazil and Portugal.

Results: Unprofessional behavior was observed frequently by students in both universities, and the mean participation rates were similar (26% and 27%). Forty-five percent of students? participation in unprofessional behavior was explained by academic year, prior observation, and judgment.

Discussion: The results indicate that once students have observed, participated in or misjudged unprofessional behavior, they tend to participate in and misjudge such behavior. The frequency with which students judged behaviors they had observed or participated in as ?borderline? or unprofessional could mean that they are experiencing moral distress.

Conclusion: Proper discussion of unprofessional behavior should foster a broad debate to encourage empowered students, faculties, and physicians to co-create a more professional environment for patient care.     

A mixture of pesticides at environmental concentrations induces oxidative stress and cholinergic effects in the neotropical fish Rhamdia quelen

The insecticides imidacloprid (IMI), a neonicotinoid, and propoxur (PRO), an N-methylcarbamate compound, are pesticides widely used throughout the world. Although they are not used together to combat pests, both are often found in freshwater near agricultural areas. Thereby, the goal of this study was to evaluate the additive effects of IMI and PRO mixtures at environmental concentrations in relation to isolated compounds on Rhamdia quelen, a neotropical fish. The fish was exposed to IMI (0.11 µg/L), PRO (0.039 µg/L), or Mix (0.11 µg/L IMI plus 0.039 µg/L PRO) during 96 h. Glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), acetylcholinesterase (AChE) activities were determined. To verify oxidative damage thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC), reactive oxygen species contents (ROS), antioxidant capacity against peroxides (ACAP) were determined in gills, liver, brain and muscle. The results shows that a mixture of these pesticides at environmental concentrations inhibited acetylcholinesterase activity in the brain and induced oxidative damage in all analyzed tissues. These results reinforce the hypothesis that mixture of contaminants present in environment could induce additive or synergistic effects on fish species.

     

Spirometry‐adjusted fraction of exhaled nitric oxide increases accuracy for assessment of asthma control in children

Spirometry and exhaled nitric oxide are two important complimentary tools to identify and assess asthma control in children. We aimed to determine the ability of a new suggested spirometry‐adjusted fraction of exhaled nitric oxide (NO) index in doing that. A random sample of 1602 schoolchildren were screened by a health questionnaire, skin prick tests, spirometry with bronchodilation and exhaled NO. A total of 662 children were included with median (IQR) exhaled NO 11(14) ppb. Receiver operating characteristic (ROC) curves using exhaled NO equations from Malmberg, Kovesi and Buchvald, and spirometry‐adjusted fraction of exhaled NO values were applied to identify asthmatic children and uncontrolled asthma. Receiver operating characteristic (ROC) curves failed to identify asthmatic children (all AUC < 0.700). Spirometry‐adjusted fraction of exhaled NO/FEV₁ (AUC = 0.712; P = .010) and NO/FEF_25%‐75% (AUC = 0.735 P = .004) had a fair and increased ability to identify uncontrolled disease compared with exhaled NO (AUC = 0.707; P = .011) or the Malmberg equation (AUC = 0.701; P = .014). Sensitivity and specificity identifying non‐controlled asthma were 59% and 81%, respectively, for the cut‐off value of 9.7 ppb/L for exhaled NO/FEV₁, and 40% and 100% for 15.7 ppb/L/s for exhaled NO/FEF_25%‐75%. Exhaled NO did not allow to identify childhood asthma. Spirometry‐adjusted fraction of exhaled NO performed better‐assessing asthma control in children. Thus, although more validation studies are needed, we suggest its use in epidemiological studies to assess asthma control.