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PubMed2006

Early versus delayed enteral nutrition support for burn injuries.

BACKGROUND: A burn injury increases the body's metabolic demands, and therefore nutritional requirements. Provision of an adequate supply of nutrients is believed to lower the incidence of metabolic abnormalities, thus reducing septic morbidity, improving survival rates, and decreasing hospital length of stay. Enteral nutrition support is the best feeding method for patients who are unable to achieve an adequate oral intake to maintain gastrointestinal functioning, however, its timing (i.e. early versus late) needs to be established. OBJECTIVES: To assess the effectiveness and safety of early versus late enteral nutrition support in adults with burn injury. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, issue 1, 2006), the Cochrane Injuries Group's Specialised Register, MEDLINE (1966 to May week 1, 2006), EMBASE (1980 to week 17, 2005) and CINAHL (1982 to May week 1, 2006). SELECTION CRITERIA: We included all randomised controlled trials comparing early enteral nutrition support (within 24 hours of injury) versus delayed enteral support (greater than 24 hours). DATA COLLECTION AND ANALYSIS: Two authors used standardised forms to independently extract the data. Each trial was assessed for internal validity with differences resolved by discussion. MAIN RESULTS: A total of three randomised controlled trials were eligible for inclusion in this review. Results of the studies indicate that evidence about the benefit of early enteral nutritional support on standardised clinical outcomes such as length of hospital stay and mortality, remains inconclusive. Similarly, the question of whether early enteral feeding influenced or decreased metabolic rate as documented in part by our included studies, remains uncertain. AUTHORS' CONCLUSIONS: This systematic review has not found sufficient evidence to support or refute the effectiveness of early versus late enteral nutrition support in adults with burn injury. The trials showed some promising results that would suggest early enteral nutrition support may blunt the hypermetabolic response to thermal injury, but this is insufficient to provide clear guidelines for practice. Further research incorporating larger sample sizes and rigorous methodology that utilises valid and reliable outcome measures, is essential.

Adult↗

PubMed2026

Integrated Genomic and Tumor Microenvironment Subtyping Improved Risk Stratification in Primary Central Nervous System Lymphoma.

Current prognostic models fail to capture the biological complexity of primary central nervous system lymphoma (PCNSL). We integrated whole-genome sequencing and multiplex immunofluorescence in 68 treatment-naïve patients to define four genomic subtypes (C1, C2, C3, and C4) with divergent survival (C4 worst: median overall survival [OS], 26 months). In parallel, a novel tumor microenvironment (TME) classification based on CD8+T/M2 macrophage ratio stratified patients into High (> 1.5), Intermediate (0.8-1.5), and Low (< 0.8) groups. Unexpectedly, the Intermediate TME group showed the poorest outcomes (5-year OS: 10%). Integration revealed a lethal subgroup (C4 + Intermediate TME; 9.8% of cohort) with a median OS of 3.0 months (hazard ratio = 7.24, p = 0.006). Prognostic nomograms incorporating these subtypes showed promising discriminative performance in internal validation (C-index > 0.78), but external validation is needed. Together, these findings identify a high-risk biological subset and provide a hypothesis-generating framework for future biomarker-driven risk stratification and therapeutic discovery in PCNSL.

Humans↗

PubMed2003

Efficacy of etanercept for the treatment of juvenile idiopathic arthritis according to the onset type.

OBJECTIVE: To assess the efficacy of etanercept in patients with juvenile idiopathic arthritis (JIA), and to assess the tolerance of these patients to etanercept. METHODS: All JIA patients with active chronic polyarthritis, who were first treated with etanercept between November 1999 and June 2001 in 18 French centers because of poor response or intolerance to methotrexate, were included in this open-label, prospective, multicenter study. A standardized questionnaire was sent to the treating physicians. We assessed the validated international core-set score for JIA activity every 3 months and performed an intent-to-treat analysis. We also compared the risk of treatment failure in patients defined as having systemic-onset, oligoarticular-onset, or polyarticular-onset JIA. RESULTS: Sixty-one patients were enrolled and were followed up for a median of 13 months. Treatment had to be stopped in 1 patient who became pregnant and in 12 patients due to severe side effects, including neurologic or psychiatric disorders, retrobulbar optic neuropathy, major weight gain, severe infection, cutaneous vasculitis with systemic symptoms, hemorrhagic diarrhea, uveitis flare, and pancytopenia. All of these side effects disappeared after discontinuation of etanercept. Crohn's disease was subsequently diagnosed in 1 child. Scores improved by > or =30% in 73% of patients after 3 months, but this proportion decreased to 39% after 12 months. The response rate was significantly lower in patients with systemic-onset JIA than in those with oligoarticular- or polyarticular-onset JIA. CONCLUSION: Treatment of JIA with etanercept may be associated with a wide spectrum of severe side effects. Although most patients initially respond to etanercept, this initial response is not always followed by sustained improvement over longer periods of time. In addition, the higher rate of treatment failure in the group with systemic-onset JIA indicates that these patients in particular may require alternative treatments.

Adolescent↗

PubMed2005

Quantification of mortality risk after abdominal aortic aneurysm repair.

BACKGROUND: The study was designed to evaluate the Acute Physiology And Chronic Health Evaluation (APACHE) II risk scoring system in abdominal aortic aneurysm (AAA) surgery. The aim was to create an APACHE-based risk stratification model for postoperative death. METHODS: Prospective postoperative APACHE II data were collected from patients undergoing AAA repair over a 9-year interval from 24 intensive care units (ICUs) in the Thames region. A multilevel logistic regression model (APACHE-AAA) for in-hospital mortality was developed to adjust for both case mix and the variation in outcome between ICUs. RESULTS: A total of 1896 patients were studied. The in-hospital mortality rate among the 1289 patients who had elective AAA repair was 9.6 (95 per cent confidence interval (c.i.) 8.0 to 11.2) per cent and that among the 605 patients who had an emergency repair was 46.9 (95 per cent c.i. 43.0 to 50.9) per cent. Four independent predictors of death were identified: age (odds ratio (OR) 1.05 (95 per cent c.i. 1.03 to 1.07) per year increase), Acute Physiology Score (OR 1.14 (95 per cent c.i. 1.12 to 1.17) per unit increase), emergency operation (OR 4.86 (95 per cent c.i. 3.64 to 6.52)) and chronic health dysfunction (OR 1.43 (95 per cent c.i. 1.04 to 1.97)). The APACHE-AAA model was internally valid, as shown by calibration (Hosmer-Lemeshow C statistic: chi(2) = 6.14, 8 d.f., P = 0.632), discrimination properties (area under receiver-operator characteristic curve 0.845) and subgroup analysis. There was no significant variation in outcome between hospitals. CONCLUSION: APACHE-AAA was shown to be an accurate risk-stratification model that could be used to quantify the risk of death after AAA surgery. It might also be used to determine the relative impact of ICU over high-dependency unit care.

APACHE↗

PubMed2005

Reflex high-risk human papillomavirus DNA testing (Hybrid Capture 2) of bloody ThinPrep specimens with atypical squamous cells of undetermined significance interpretation: does pretreatment with acetic acid affect test performance?

BACKGROUND: The current study was conducted to evaluate the efficacy of human papillomavirus (HPV) DNA testing of residual ThinPrep specimens, which were pretreated with acetic acid to optimize cellularity with a special focus on atypical squamous cells of undetermined significance (ASCUS) specimens. METHODS: A total of 120 ThinPrep gynecologic samples were chosen for a pilot study including cases with a normal or abnormal interpretation and those with or without blood. Each residual specimen was divided into two portions. One portion was treated with glacial acetic acid (GAA) and the other half remained untreated. Both aliquots were tested for high-risk HPV DNA using the Hybrid Capture 2 test. After internal validation, reflex HPV DNA testing was performed on all consecutive 1776 ASCUS specimens including 98 acid-washed bloody specimens in routine practice. RESULTS: Of the 120 specimens with paired aliquots, 117 specimens had concordant HPV DNA test results in the treated and untreated groups with a squared correlation coefficient value of 0.97 and a kappa value of 0.95. Subsequently, in the clinical setting, 43 of 98 (43.9%) acid-washed specimens and 845 of 1676 (50.4%) routine specimens with an ASCUS interpretation tested positive for high-risk HPV DNA. There was no statistically significant difference noted between these two groups with regard to age, percentage HPV DNA positivity, or viral load. CONCLUSIONS: The pretreatment of bloody specimens with GAA did not appear to significantly affect high-risk HPV DNA testing in specimens with an ASCUS interpretation.

Acetates↗

PubMed2003

Investigating the structure of the eating inventory (three-factor eating questionnaire): a confirmatory approach.

OBJECTIVE: To investigate the internal structure of the Eating Inventory using confirmatory factor analytic (CFA) methods. METHOD: Female participants in a population-based twin study (N = 1,510) completed a reduced version of the Eating Inventory as part of a larger study of eating behaviors. Two CFA estimation methods were implemented using LISREL and Mplus to evaluate three different factor structures reported in the literature. RESULTS: Overall results for Stunkard and Messick's (1985) three-factor model indicated a poor fit to these data. The structure reported by Ganley resulted in an improper solution with factor correlations over 1 and several loadings estimated near 0 or with negative signs. The model proposed by Hyland et al. also fit poorly for all three models, the pattern of loadings on the Restraint factor proved most difficult to interpret. DISCUSSION: This study represents the first application of these confirmatory methods to the three subscales of the Eating Inventory. The instrument, as administered in this study, did not conform well to the structures proposed in previous studies. Because the Eating Inventory is recommended as a treatment planning tool, poor replication of the constructs purported to be assessed by this instrument underscores the importance of further internal validation research.

Adult↗

PubMed2004

Measuring inequality in self-reported health-discussion of a recently suggested approach using Finnish data.

Health surveys often include a general question on self-assessed health (SAH), usually measured on an ordinal scale with three to five response categories, from 'very poor' or 'poor' to 'very good' or 'excellent'. This paper assesses the scaling of responses on the SAH question. It compares alternative procedures designed to impose cardinality on the ordinal responses. These include OLS, ordered probit and interval regression approaches. The cardinal measures of health are used to compute and decompose concentration indices for income-related inequality in health. Results are provided using Finnish data on 15D and the SAH questions. Further evidence emerges for the internal validity of a method used in a pioneering study by van Doorslaer and Jones which was based on Canadian data on the McMaster Health Utility Index Mark III (HUI) and SAH. The study validates the conclusions drawn by van Doorslaer and Jones. It confirms that the interval regression approach is superior to OLS and ordered probit regression in assessing health inequality. However, regarding the choice of scaling instrument, it is concluded that the scaling of SAH categories and, consequently, the measured degree of inequality, are sensitive to characteristics of the chosen scaling instrument.

Female↗

PubMed1997

Stability and performance of a population pharmacokinetic model.

This study aimed to determine the stability (in terms of covariate selection) of a population pharmacokinetic model and evaluate its performance in the absence of a test data set. Data from 88 full-term infants, 11 of whom were human immunodeficiency virus (HIV)-seropositive, taking an antiinfective agent were analyzed using exploratory data analysis methods and the nonlinear mixed-effects modeling (NONMEM) program to obtain the final population pharmacokinetic model. The stability of the population pharmacokinetic model was tested using the nonparametric bootstrap approach in four steps: 1) with the base pharmacokinetic model, 100 bootstrap replicates of the original data were generated by sampling with replacement; 2) ascertainment that each bootstrap data replicate was described by the basic structural model using the NONMEM objective function; 3) generalized additive modeling (GAM) applied to empiric Bayesian estimates for covariate selection at alpha = 0.05 and a frequency (f) cutoff value of 0.50; and 4) NONMEM population model building using covariates selected in the third step with alpha = 0.005. Performance of the population pharmacokinetic model was evaluated using 200 additional bootstrap replicates of the data by fitting the model obtained in step 4 to them. Parameters obtained were compared with those obtained in the model stability step, and improved prediction error, a measure of predictive accuracy as an index of internal validation, was computed. The reciprocal of serum creatinine (RSC; f = 0.73) and HIV (f = 0.70) were selected by GAM as predictors of clearance (Cl). The population pharmacokinetic model obtained without the determination of model stability included RSC as a predictor of Cl, but the final model from the model stability step included both HIV and RSC as predictors of Cl. Final population pharmacokinetic parameters were obtained with this model fitted to the original data; however, the 95% confidence interval on the HIV status regression coefficient included zero, indicating no significance. The mean parameter estimates obtained with the additional 200 bootstrap replicates of data were within 15% of those obtained with the final model at the regression stability step. Bootstrap resampling procedure is useful for evaluating the stability and performance of a population model by repeatedly fitting it to the bootstrap samples when there is no test data set.

Adolescent↗

PubMed2007

In vitro pyrogen test--A new test method for solid medical devices.

Medical devices manufactured for implantation into humans must be free of any contamination with viable bacteria. However, remnants of dead bacteria and bacterial components alone may induce an inflammatory immune response. Pyrogen tests for such inflammatory contaminations are generally performed either by determining the content of lipopolysaccharide in rinsing solutions of batch samples by limulus amoebocyte lysate assay, by injecting the rinsing solutions into rabbits or by implanting batch samples into rabbits and measuring change of body temperature. In this study, we show that the in vitro pyrogen test (IPT), which measures the release of the inflammatory cytokine IL-1beta in fresh or cryopreserved human whole blood, can be used to assess the pyrogenic contamination of implantable medical devices. This test was used to check neurosurgical implants, namely aneurysm clips, as a proof of principle. Owing to the direct contact of the test material with the blood cells, this test does not require rinsing procedures, which have variable efficacy. The use of human blood ensures the detection of all substances that are pyrogenic for humans and reflects their relative potency. The safety of the products as delivered could be confirmed. The effects of sterilization and depyrogenization procedures on intentional pyrogenic contaminations of samples could be followed. This new application of the already internationally validated method promises to replace further rabbit pyrogen tests. It generates extremely sensitive results with an extended range of detectable pyrogenic contaminants.

Equipment and Supplies↗

PubMed2002

Comparison of right ventricular volume measurement between segmented k-space gradient-echo and steady-state free precession magnetic resonance imaging.

PURPOSE: To compare right ventricular volume measurements and their reproducibility between steady-state free precession (SSFP) and conventional turbo gradient-echo (TGE) imaging. MATERIALS AND METHODS: Right ventricular volumes and observer variabilities were compared between SSFP and TGE in 31 subjects (21 normal volunteers and 10 subjects with heart failure). For further internal validation of the right ventricular volumes, the left ventricle (LV) and right ventricle (RV) stroke volumes were compared for the normal volunteers. RESULTS: The volumes as measured by SSFP were significantly larger than for TGE (mean bias end-diastolic volume [EDV] 11.1 +/- 14.2, end-systolic volume [ESV] 9.8 +/- 9.75). SSFP had lower interobserver variability (SSFP EDV -10.1 +/- 11.6 vs. TGE EDV -6.2 +/- 18.5) and intra-observer variability (SSFP EDV -2.0 +/- 6.3 vs. TGE EDV -6.1 +/- 14.8). The mean absolute differences between LV and RV stroke volumes for 21 normal volunteers were: TGE 5.8 +/- 12.9 (r(2) = 0.72), SSFP 4.6 +/- 6.9 (r(2) = 0.92). CONCLUSION: SSFP and TGE yield different measurement values of RV volumes with SSFP, providing a more reproducible measurement.

Case-Control Studies↗

PubMed2006

Maximizing follow-up in longitudinal studies of traumatized populations.

Although longitudinal research is essential in understanding the nature and course of posttraumatic mental health problems, high rates of attrition often threaten the internal validity of such studies and make results hard to interpret. C. K. Scott (2004) developed an approach to minimizing attrition in longitudinal studies that consistently yielded retention rates in excess of 90% through to 2-year follow-up. In this article, the authors discuss the interface between trauma exposure and participation in longitudinal research, before describing in detail a model to address those effects. The effectiveness of the model is examined with reference to traumatic stress in a large community sample (N = 887) with eight waves of data over 2 years.

Adult↗

PubMed2006

Efficacy and safety of herbal medicines for idiopathic Parkinson's disease: a systematic review.

The objective of this study is to assess the efficacy and safety of herbal medicines (HMs), as a monotherapy or adjunct therapy, compared to placebo or conventional approaches in the treatment of idiopathic Parkinson's disease (PD). We conducted a systematic review of randomized controlled trials from both conventional and alternative medicine sources. Outcome measures were overall improvement, quality of life, reduction of levodopa dose, and adverse events. Nine studies were included, each testing a different HM. Six of the trials had limited internal validity due to major flaws in design, including the lack of proper randomization; insufficient blinding; unclear inclusive criteria in terms of diagnostic criteria, baseline staging, and duration of disease; lack of proper sample size calculation; and insufficient data analysis. Imbalances in gender and ethnicity among the patients in the included trials were observed. No major adverse events emerged, and no specific pattern was detected from the trials describing such data. In addition to major methodological defects, heterogeneity in (1) HM tested, (2) control treatment, and (3) outcome measure hindered in-depth data analysis and synthesis. Current evidence is insufficient to evaluate the efficacy and safety of various HMs. Further studies with improved trial design and reporting, with assessment on cost-effectiveness, quality of life, and qualitative data are warranted.

Antiparkinson Agents↗

PubMed2005

Assessment of executive function in preschool-aged children.

Assessment of the overarching self-regulatory mechanisms, or executive functions, in any age group is challenging, in part due to the complexity of this domain, in part due to their dynamic essence, and in part due to the inextricable links between these central processes and the associated domain-specific processes, such as language, motor function, and attention, over which they preside. While much progress has been made in clinical assessment approaches for measuring executive functions in adults and to some extent in adolescents and school-aged children, the toolkit for the preschool evaluator remains sparse. The past decade, however, has seen a substantial increase in attention to executive functions in very young children from a developmental neuropsychological perspective. With this has come a necessity for better, more specific, and more internally valid performance measures, many of which are now described in the experimental literature. Few such tasks, however, have adequately demonstrated psychometric properties for clinical application. We present two performance tasks designed to tap selective aspects of executive function in preschoolers that are emerging from the experimental laboratory and hold promise of appropriate reliability and validity for the clinical laboratory. Performance tests alone, however, are insufficient to develop a comprehensive picture of a child's executive functioning. Thus, we present a rating scale of preschoolers' executive function in the everyday context, and advocate a model of executive function assessment that incorporates both controlled performance tasks that target specific aspects of executive function and parent/teacher ratings that target more global aspects of self-regulation in the everyday context.

Aptitude Tests↗

PubMed2003

Developing risk-adjusted 30-day hospital mortality rates.

This article describes one risk-adjustment method useful for minimizing threats to internal validity that stem from the impact on the outcomes under investigation from patients' own characteristics and their associated risks. Mortality is the outcome used to illustrate the risk-adjustment approach. A two-step approach to outcomes research is suggested. The first step includes risk-adjusting outcomes for patient characteristics by developing standard mortality rates. In the second step these risk-adjusted standard rates can be used as dependent variables in outcomes analytic models. This article focuses on the first step. In the current study risk adjustment resulted in changes in both absolute values and rank ordering of hospital mortality rates compared to crude rates. This procedure is useful for developing risk-adjusted outcomes with administrative data similar to those used in this study.

Aged↗

PubMed1986

Clinical and cost-saving effects of psychoeducational interventions with surgical patients: a meta-analysis.

Meta-analysis of 102 studies was conducted to examine how psychoeducational interventions influence recovery, pain, psychological well-being, and satisfaction with care among hospitalized adult surgery patients. Statistically reliable and positive effects were found on each of these four classes of outcome. Further analyses showed that the effects could not be attributed to biases associated with the decision to publish, low internal validity, measurement subjectively, or a Hawthorne effect. Analyses of the subset of outcomes with most direct cost implications showed that positive, cost-relevant effects were obtained across a wide range of patients, treatment providers, hospital settings, and historic periods.

Adolescent↗

PubMed2003

Assessing non-inferiority of a new treatment in a three-arm clinical trial including a placebo.

In non-inferiority trials, where non-inferiority of a new experimental drug compared to an active control has to be shown, it may be advisable to use an additional placebo group for internal validation if ethically justifiable. The focus of this paper is on such designs. Assuming normality and homogeneity of variances we will derive a statistical test procedure which turns out to be equivalent to the assessment based on Fieller's confidence interval. Based on the power function of this test, sample size calculations are carried out to achieve a given power. Additionally, the optimal allocation of the total sample size is derived. As an alternative to this parametric procedure, the bootstrap percentile interval is discussed and finally compared with Fieller's confidence interval in a study on mildly asthmatic patients.

Anti-Asthmatic Agents↗

PubMed1996

Self-Serving Influences on Adolescents' Evaluations of Belief-Relevant Evidence

To examine the effects of motivation and intellectual ability on adolescent reasoning, 50 adolescents were presented "scientific" evidence relevant to their religious affiliations. Tests of fluid and crystallized intelligence were also administered. Belief-consistent evidence portrayed adolescents' religious affiliations favorably; inconsistent evidence portrayed these religions unfavorably; neutral evidence was irrelevant to participants' religions. Each type of evidence contained a threat to internal validity, detection of which would have discredited the evidence. Results indicated that validity threats were detected most frequently in belief-inconsistent evidence, indicating that adolescents' reasoning is systematically biased to protect and promote their preexisting beliefs. A manipulation designed to motivate adolescents toward greater accuracy improved overall performance, but did not reduce bias. Crystallized intellectual ability was linked to absolute level of reasoning and to the effectiveness of the accuracy manipulation. However, reasoning biases cut across levels of intellectual ability. The role played by depth of processing in supporting biased reasoning is discussed.

Journal Article↗

PubMed1998

Quantitation of glutaminase mRNA in enterocytes using competitive RT-PCR.

The concentration of mRNA within the intestinal mucosa is usually measured by either Northern blot analysis or semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). However, these methods are limited by a lack of valid internal controls, low sensitivity, and large differences in the concentration of the internal control and target gene. The authors present an alternative method using competitive RT-PCR to measure glutaminase mRNA in isolated enterocytes.

Animals↗