Urinary pharmacokinetics of betalains following consumption of red beet juice in healthy humans.

The aim of the present pilot study was to characterise the renal elimination of betalains after consumption of red beet juice (RBJ). Six healthy, non-smoking female volunteers were given a single oral dose of either 500 mL of a commercial RBJ containing 362.7 mg of betalains and 500 mL of tap water, respectively, in a sequential manner. Urine was collected in intervals up to 24 h post-dose. Renal excretion of betalains was determined spectrophotometrically and quantified as betanin-equivalents. In addition, the identity of individual compounds was confirmed by HPLC coupled with diode-array detection and positive ion electrospray mass spectrometry, respectively. The amount (mean+/-S.D.) of intact betalains (betanin and isobetanin) recovered in urine was 1001+/-273 microg corresponding to 0.28+/-0.08% of the administered dose. Maximum excretion rates were observed after a median tmax,R of 3.0 h (range 2.5-8.0 h) amounting to 91.7+/-30.1 microg/h. The terminal elimination rate constant (lambdaz) and the corresponding half-life were 0.097+/-0.021 h(-1) and 7.43+/-1.47 h, respectively. Using the lambdaz estimates obtained the expected total betalain amount excreted in urine was 1228+/-291 microg. Based on the results obtained it is assumed that either the bioavailability of the betalains is low or that renal clearance is a minor route of systemic elimination for these compounds. The urinary excretion rates of unmetabolised betalains were fast and appeared to be monoexponential suggesting a one-compartment model. In order to get a more complete picture of the pharmacokinetics and health-promoting properties of red beet betalains, quantitative data on betalain bioavailability should include measurements of unchanged compounds and their corresponding metabolites in plasma, urine and bile.     

Electroconvulsive therapy and falls in the elderly

Electroconvulsive therapy (ECT) is commonly used in the practice of geriatric psychiatry. Although it has been found to be both safe and effective, one of the most common complications associated with ECT is falls. A logistic regression model was created to identify independent risk factors for falls in the elderly. Two risk factors were identified: the number of ECT treatments and the diagnosis of Parkinson disease. Further studies are needed to develop strategies aimed at reducing the number of falls. In the meantime, clinicians need to be aware that falls represent an important complication associated with ECT.     

Advanced Psychometric Methods for Developing and Evaluating Cut-Point-Based Indicators

In this study, we offer some advice on the use of empirical techniques to create categorical indicators from responses to multiple survey questions that ostensibly compose scales. We discuss the use of advanced psychometric methods, including confirmatory factor analysis for ordered categorical measures (CFA-OCM) and item response theory (IRT), to expand 12 previously published criteria for cut-point development and evaluation offered by Moore et al. (Indicators of Child Well-Being: The Promise for Positive Youth Development. Annals of the American Academy of Political and Social Science. Special Issue: Positive Development: Realizing the Potential of Youth. 591:125–145, 2004). We present an application of this advice by developing categorical cut-points for the social skills and behavior problems subscales of the U.S. National Survey of Children’s Health (NSCH) Social Competence Scale. We used data from the 2007 NSCH, a large cross-sectional, random-digit-dial telephone survey of a representative sample of the noninstitutionalized population of U.S. children 0–17 years of age. Parents of children aged 6 to 17 years (n = 63,364) responded to 4 questions about their children’s behavior problems and 4 questions about their children’s positive social skills. IRT analyses indicated that IRT model-based scores of +1.8 and −0.7 provided suitable high and low cut-points, respectively, for the behavior problems subscale. These cut-points had marginal reliabilities of 0.70 and 0.67 respectively, and corresponded to raw subscale scores of 13 and 8 IRT analyses indicated that an IRT model-based score of −1.8 provided a suitable cut-point for identifying children with low levels of positive social skills. This cut-point had a marginal reliability of 0.63 and corresponded to a raw subscale score of 13. For both subscales and cut-point sets, frequency distributions demonstrated that the cut-points identified sufficient proportions of children generally as well as within demographic subgroups. Our findings indicate that analysts can use raw subscale scores and cut-points of 13 and 8 to identify children with high, moderate, and low levels of behavior problems. Our results demonstrate that, for the positive social skills subscale, the subscale’s psychometric properties only support a single cut-point of 13 that identifies children with low levels of positive social skills. Our study highlights the iterative, empirically-based process that cut-point development should follow and shows the value of modern test theory-based psychometric methods to inform this process.     

Role of S100A8 and S100A9 in neutrophil recruitment in response to monosodium urate monohydrate crystals in the air-pouch model of acute gouty arthritis

OBJECTIVE: To examine the role of chemokines, S100A8, and S100A9 in neutrophil accumulation induced by the causative agent of gout, monosodium urate monohydrate (MSU) crystals. METHODS: MSU crystal-induced neutrophil migration was studied in the murine air-pouch model. Release of chemokines, S100A8, S100A9, and S100A8/A9 in response to MSU crystals was quantified by enzyme-linked immunosorbent assays. Recruited cells were counted following acetic blue staining, and the subpopulations were characterized by Wright-Giemsa staining of cytospins. RESULTS: MSU crystals induced the accumulation of neutrophils following injection in the air pouch, which correlated with the release of the chemokines CXCL1, CXCL2, CCL2, and CCL3. However, none of these was found to play an important role in neutrophil migration induced by MSU crystals by passive immunization with antibodies directed against each chemokine. S100A8, S100A9, and S100A8/A9 were also found at high levels in the pouch exudates following injection of MSU crystals. In addition, injection of S100A8, S100A9, or S100A8/A9 led to the accumulation of neutrophils in the murine air pouch, demonstrating their proinflammatory activities in vivo. Passive immunization with anti-S100A8 and anti-S100A9 led to a total inhibition of the accumulation of neutrophils. Finally, S100A8/A9 was found at high concentrations in the synovial fluid of patients with gout. CONCLUSION: S100A8 and S100A8/A9 are essential to neutrophil migration induced by MSU crystals. These results suggest that they might be involved in the pathogenesis of gout.