How Meta-Analysis Increases Statistical Power.

One of the most frequently cited reasons for conducting a meta-analysis is the increase in statistical power that it affords a reviewer. This article demonstrates that fixed-effects meta-analysis increases statistical power by reducing the standard error of the weighted average effect size (T?.) and, in so doing, shrinks the confidence interval around T?.. Small confidence intervals make it more likely for reviewers to detect nonzero population effects, thereby increasing statistical power. Smaller confidence intervals also represent increased precision of the estimated population effect size. Computational examples are provided for 3 effect-size indices: d (standardized mean difference), Pearson's r, and odds ratios. Random-effects meta-analyses also may show increased statistical power and a smaller standard error of the weighted average effect size. However, the authors demonstrate that increasing the number of studies in a random-effects meta-analysis does not always increase statistical power. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reformation of casein particles from alkaline-disrupted casein micelles

In this study, the properties of casein particles reformed from alkaline disrupted casein micelles were studied. For this purpose, micelles were disrupted completely by increasing milk pH to 10.0, and subsequently reformed by decreasing milk pH to 6.6. Reformed casein particles were smaller than native micelles and had a slightly lower zeta-potential. Levels of ionic and serum calcium, as well as rennet coagulation time did not differ between milk containing native micelles or reformed casein particles. Ethanol stability and heat stability, >pH 7.0, were lower for reformed casein particles than native micelles. Differences in heat stability, ethanol stability and zeta-potential can be explained in terms of the influence of increased concentrations of sodium and chloride ions in milk containing reformed casein particles. Hence, these results indicate that, if performed in a controlled manner, casein particles with properties closely similar to those of native micelles can be reformed from alkaline disrupted casein micelles.     

Shelf Life and Sensory Characteristics of Baby Spinach Subjected to Electron Beam Irradiation

Abstract: The use of ionizing radiation for the control of foodborne pathogens and extending the shelf life of fresh iceberg lettuce and fresh spinach has recently been approved by the U.S. Food and Drug Administration. The efficacy of electron beam irradiation for controlling foodborne pathogens has been reported. For this experiment, the effectiveness of electron beam irradiation on the microbiological and sensory characteristics of fresh spinach was studied. Total aerobic plate counts were reduced by 2.6 and 3.2 log CFU/g at 0.7 and 1.4 kGy, respectively. Lactic acid bacteria were reduced at both doses of e-beam but grew slowly over the 35 d of the experiment. Yeasts and molds were not reduced in samples exposed to 0.7 kGy whereas 1.4 kGy significantly reduced microbial counts. Gas compositions (O₂ and CO₂) were significantly different than controls. Oxygen levels inside the spinach sample bags decreased over time; however, O₂ levels did not drop below 1% that can induce anaerobic fermentation. CO₂ levels for all treatments increased through day 4; yet 7 d after irradiation, CO₂ level differences were not significant in both control and irradiated samples. Irradiation dose did not affect the basic tastes, aromatics, or mouth feels of fresh spinach, however; hardness attributes decreased as irradiated dose increased and slimy attributes of fresh spinach were higher in control samples compared to irradiated samples.     

Effective components of TORDIA cognitive–behavioral therapy for adolescent depression: Preliminary findings.

In this report, we conducted a secondary analysis of the Treatment of SSRI-Resistant Depression in Adolescents (TORDIA) study to explore the impact of specific cognitive–behavioral therapy (CBT) treatment components on outcome. In TORDIA, 334 youths (ages 12 to 18 years) with major depressive disorder who had failed to respond to an adequate course of selective serotonin reuptake inhibitor (SSRI) medication were randomized to a medication switch (either to an alternative SSRI or venlafaxine) with or without 12 weeks of adjunctive CBT. Participants who had more than 9 CBT sessions were 2.5 times more likely to have adequate treatment response than those who had 9 or fewer sessions. CBT participants who received problem-solving and social skills treatment components, controlling for number of sessions and other confounding variables, were 2.3 and 2.6 times, respectively, more likely to have a positive response. These preliminary findings underscore the importance of receiving an adequate number of sessions to attain an adequate clinical response. Finally, social skills and problem solving may be active elements in CBT for adolescent depression and should be considered in treatment by those working with seriously depressed youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bone cell attachment and growth on well‐characterized chitosan films

Chitosan has been widely researched for bone tissue and implant applications. While initial results are promising, there are inconsistent reports regarding the biological responses. This may be due to inadequate evaluation of chitosan material properties. This study evaluated normal human osteoblast precursor cell attachment and proliferation on a series of well‐characterized chitosan films. The chitosan films exhibited a range of properties: 76–96% degree of de‐acetylation (DDA), 2400–8200 kDa viscosity‐average molecular weight, 62–90° contact angle, 0.24–2.46% residual ash, 5.3–287 µg cm^?2 residual protein and 23–40% crystallinity. There was no trend or correlation between DDA, crystallinity, contact angle, molecular weight, residual ash or protein content and the attachment or growth of bone cells on chitosan films. All films supported higher levels of bone cell proliferation than tissue culture plastic, which supports the general hypothesis that chitosans are osteocompatible. The 78 and 92% DDA chitosan films supported the most cell proliferation, approximately 16 times that of tissue culture plastic controls, but no chitosan physiochemical property correlated with the increased cell growth. The lack of correlation is hindered since more than one physiochemical property changed for each chitosan material. Data do indicate that there may be much variability in chitosan materials, and this variability may make understanding and comparing biological performance of chitosan materials difficult. These results highlight the need for systematic characterizations of chitosan materials for predictable biomedical applications. Copyright © 2006 Society of Chemical Industry     

Evaluation of Mangosteen juice blend on biomarkers of inflammation in obese subjects: a pilot, dose finding study

Background  

The ability to reduce inflammation in overweight and obese individuals may be valuable in preventing the progression to metabolic syndrome with associated risks for heart disease and diabetes. The purpose of this study was to evaluate the effect of multiple dosages of a proprietary Mangosteen Juice blend on indicators of inflammation and antioxidant levels in obese patients with elevated C-reactive protein (CRP) levels.     

Do boys with attention-deficit/hyperactivity disorder have positive illusory self-concepts?

One hundred ninety-five boys with attention-deficit/hyperactivity disorder (ADHD) were compared with 73 comparison boys (M=9.83 years, SD=1.30) on self-perceptions relative to a teacher-rated criterion. Emphasis was placed on ADHD subgroup comparisons according to level of aggression, academic achievement, and depression compared with control boys. Consistent with the authors' prediction, ADHD boys overestimated relative to teacher report, more than did controls, in the scholastic competence, social acceptance, and behavioral conduct domains. Examination of discrepancy scores (child rating--teacher rating) by comorbidity subgroups suggested that aggressive and low-achieving ADHD boys tended to overestimate their competence the most in the domains in which they were the most impaired. Results are discussed in terms of prior literature on "positive illusions" in ADHD children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypothesis validity of clinical research.

Hypothesis validity refers to the extent to which research results reflect theoretically derived predictions about the relations between or among constructs. The role of hypotheses in theory testing is discussed. Four threats to hypothesis validity are presented: (a) inconsequential research hypotheses, (b) ambiguous research hypotheses, (c) noncongruence of research hypotheses and statistical hypotheses, and (d) diffuse statistical hypotheses and tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biological and technical variables affecting immunoassay recovery of cytokines from human serum and simulated vaginal fluid: a multicenter study

The increase of proinflammatory cytokines in vaginal secretions may serve as a surrogate marker of unwanted inflammatory reaction to microbicide products topically applied for the prevention of sexually transmitted diseases, including HIV-1. Interleukin (IL)-1beta and IL-6 have been proposed as indicators of inflammation and increased risk of HIV-1 transmission; however, the lack of information regarding detection platforms optimal for vaginal fluids and interlaboratory variation limit their use for microbicide evaluation and other clinical applications. This study examines fluid matrix variants relevant to vaginal sampling techniques and proposes a model for interlaboratory comparisons across current cytokine detection technologies. IL-1beta and IL-6 standards were measured by 12 laboratories in four countries, using 14 immunoassays and four detection platforms based on absorbance, chemiluminescence, electrochemiluminescence, and fluorescence. International reference preparations of cytokines with defined biological activity were spiked into (1) a defined medium simulating the composition of human vaginal fluid at pH 4.5 and 7.2, (2) physiologic salt solutions (phosphate-buffered saline and saline) commonly used for vaginal lavage sampling in clinical studies of cytokines, and (3) human blood serum. Assays were assessed for reproducibility, linearity, accuracy, and significantly detectable fold difference in cytokine level. Factors with significant impact on cytokine recovery were determined by Kruskal-Wallis analysis of variance with Dunn's multiple comparison test and multiple regression models. All assays showed acceptable intra-assay reproducibility; however, most were associated with significant interlaboratory variation. The smallest reliably detectable cytokine differences ( P < 0.05) derived from pooled interlaboratory data varied from 1.5- to 26-fold depending on assay, cytokine, and matrix type. IL-6 but not IL-1beta determinations were lower in both saline and phosphate-buffered saline as compared to vaginal fluid matrix, with no significant effect of pH. The (electro)chemiluminescence-based assays were most discriminative and consistently detected <2-fold differences within each matrix type. The Luminex-based assays were less discriminative with lower reproducibility between laboratories. These results suggest the need for uniform vaginal sampling techniques and a better understanding of immunoassay platform differences and cross-validation before the biological significance of cytokine variations can be validated in clinical trials. This investigation provides the first standardized analytic approach for assessing differences in mucosal cytokine levels and may improve strategies for monitoring immune responses at the vaginal mucosal interface.