Showing papers by "Virginia Commonwealth University published in 2002"

Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection.

Abstract: Background Treatment with peginterferon alfa-2a alone produces significantly higher sustained virologic responses than treatment with interferon alfa-2a alone in patients with chronic hepatitis C virus (HCV) infection. We compared the efficacy and safety of peginterferon alfa-2a plus ribavirin, interferon alfa-2b plus ribavirin, and peginterferon alfa-2a alone in the initial treatment of chronic hepatitis C. Methods A total of 1121 patients were randomly assigned to treatment and received at least one dose of study medication, consisting of 180 μg of peginterferon alfa-2a once weekly plus daily ribavirin (1000 or 1200 mg, depending on body weight), weekly peginterferon alfa-2a plus daily placebo, or 3 million units of interferon alfa-2b thrice weekly plus daily ribavirin for 48 weeks. Results A significantly higher proportion of patients who received peginterferon alfa-2a plus ribavirin had a sustained virologic response (defined as the absence of detectable HCV RNA 24 weeks after cessation of therapy) th...

The Richmond Agitation-Sedation Scale Validity and Reliability in Adult Intensive Care Unit Patients

Abstract: Sedative medications are widely used in intensive care unit (ICU) patients. Structured assessment of sedation and agitation is useful to titrate sedative medications and to evaluate agitated behavior, yet existing sedation scales have limitations. We measured inter-rater reliability and validity of a new 10-level (+4 “combative” to −5 “unarousable”) scale, the Richmond Agitation–Sedation Scale (RASS), in two phases. In phase 1, we demonstrated excellent (r = 0.956, lower 90% confidence limit = 0.948; κ = 0.73, 95% confidence interval = 0.71, 0.75) inter-rater reliability among five investigators (two physicians, two nurses, and one pharmacist) in adult ICU patient encounters (n = 192). Robust inter-rater reliability (r = 0.922–0.983) (κ = 0.64–0.82) was demonstrated for patients from medical, surgical, cardiac surgery, coronary, and neuroscience ICUs, patients with and without mechanical ventilation, and patients with and without sedative medications. In validity testing, RASS correlated highly (r = 0.93)...

Statistical Methods in Diagnostic Medicine

Abstract: Preface. Acknowledgments. 1. Introduction. 1.1 Why This Book? 1.2 What Is Diagnostic Accuracy? 1.3 Landmarks in Statistical Methods for Diagnostic Medicine. 1.4 Software. 1.5 Topics not Covered in This Book. 1.6 Summary. I BASIC CONCEPTS AND METHODS. 2. Measures of Diagnostic Accuracy. 2.1 Sensitivity and Specificity. 2.2 The Combined Measures of Sensitivity and Specificity. 2.3 The ROC Curve. 2.4 The Area Under the ROC Curve. 2.5 The Sensitivity at a Fixed FPR. 2.6 The Partial Area Under the ROC Curve. 2.7 Likelihood Ratios. 2.8 Other ROC Curve Indices. 2.9 The Localization and Detection of Multiple Abnormalities. 2.10 Interpretation of Diagnostic Tests. 2.11 Optimal Decision Threshold on the ROC Curve. 2.12 Multiple Tests. 3. The Design of Diagnostic Accuracy Studies. 3.1 Determining the Objective of the Study. 3.2 Identifying the Target Patient Population. 3.3 Selecting a Sampling Plan for Patients. 3.3.1 Phase I: Exploratory Studies. 3.3.2 Phase II: Challenge Studies. 3.3.3 Phase III: Clinical Studies. 3.4 Selecting the Gold Standard. 3.5 Choosing a Measure of Accuracy. 3.6 Identifying the Target Reader Population. 3.7 Selecting a Sampling Plan for Readers. 3.8 Planning the Data Collection. 3.8.1 Format for the Test Results. 3.8.2 Data Collection for the Reader Studies. 3.8.3 Reader Training. 3.9 Planning the Data Analyses. 3.9.1 Statistical Hypotheses. 3.9.2 Reporting the Test Results. 3.10 Determining the Sample Size. 4. Estimation and Hypothesis Testing in a Single Sample. 4.1 Binary Scale Data. 4.1.1 Sensitivity and Specificity. 4.1.2 The Sensitivity and Specificity of Clustered Binary Data. 4.1.3 The Likelihood Ratio (LR). 4.1.4 The Odds Ratio. 4.2 Ordinal Scale Data. 4.2.1 The Empirical ROC Curve. 4.2.2 Fitting a Smooth Curve (Parametric Model). 4.2.3 Estimation of Sensitivity at a Particular FPR. 4.2.4 The Area and Partial Area Under the ROC Curve (Parametric Model). 4.2.5 The Area Under the Curve (Nonparametric Method). 4.2.6 Nonparametric Analysis of Clustered Data. 4.2.7 The Degenerate Data. 4.2.8 Choosing Between Parametric and Nonparametric Methods. 4.3 Continuous Scale Data. 4.3.1 The Empirical ROC Curve. 4.3.2 Fitting a Smooth ROC Curve (Parametric and Nonparametric Methods). 4.3.3 Area Under the ROC Curve (Parametric and Nonparametric). 4.3.4 Fixed FPR The Sensitivity and Decision Threshold. 4.3.5 Choosing the Optimal Operating Point. 4.3.6 Choosing Between Parametric and Nonparametric Techniques. 4.4 Hypothesis Testing About the ROC Area. 5. Comparing the Accuracy of Two Diagnostic Tests. 5.1 Binary Scale Data. 5.1.1 Sensitivity and Specificity. 5.1.2 Sensitivity and Specificity of Clustered Binary Data. 5.2 Ordinal and Continuous Scale Data. 5.2.1 Determining the Equality of Two ROC Curves. 5.2.2 Comparing ROC Curves at a Particular Point. 5.2.3 Determining the Range of FPR for Which TPR Differ. 5.2.4 A Comparison of the Area or Partial Area. 5.3 Tests of Equivalence. 6. Sample Size Calculation. 6.1 The Sample Size for Accuracy Studies of a Single Test. 6.1.1 Sensitivity and Specificity. 6.1.2 The Area Under the ROC Curve. 6.1.3 The Sensitivity at a Fixed FPR. 6.1.4 The Partial Area Under the ROC Curve. 6.2 The Sample Size for the Accuracy of Two Tests. 6.2.1 Sensitivity and Specificity. 6.2.2 The Area Under the ROC Curve. 6.2.3 The Sensitivity at a Fixed FPR. 6.2.4 The Partial Area Under the ROC Curve. 6.3 The Sample Size for Equivalent Studies of Two Tests. 6.4 The Sample Size for Determining a Suitable Cutoff Value. 7. Issues in Meta Analysis for Diagnostic Tests. 7.1 Objectives. 7.2 Retrieval of the Literature. 7.3 Inclusion Exclusion Criteria. 7.4 Extracting Information From the Literature. 7.5 Statistical Analysis. 7.6 Public Presentation. II ADVANCED METHODS. 8. Regression Analysis for Independent ROC Data. 8.1 Four Clinical Studies. 8.1.1 Surgical Lesion in a Carotid Vessel Example. 8.1.2 Pancreatic Cancer Exampl. 8.1.3 Adult Obesity Example. 8.1.4 Staging of Prostate Cancer Example. 8.2 Regression Models for Continuous Scale Tests. 8.2.1 Indirect Regression Models for Smooth ROC Curves. 8.2.2 Direct Regression Models for Smooth ROC Curves. 8.2.3 MRA Use for Surgical Lesion Detection in the Carotid Vessel. 8.2.4 Biomarkers for the Detection of Pancreatic Cancer. 8.2.5 Prediction of Adult Obesity by Using Childhood BMI Measurements. 8.3 Regression Models for Ordinal Scale Tests. 8.3.1 Indirect Regression Models for Latent Smooth ROC Curves. 8.3.2 Direct Regression Model for Latent Smooth ROC Curves. 8.3.3 Detection of Periprostatic Invasion With US. 9. Analysis of Correlated ROC Data. 9.1 Studies With Multiple Test Measurements of the Same Patient. 9.1.1 Indirect Regression Models for Ordinal Scale Tests. 9.1.2 Neonatal Examination Example. 9.1.3 Direct Regression Models for Continuous Scale Tests. 9.2 Studies With Multiple Readers and Tests. 9.2.1 A Mixed Effects ANOVA Model for Summary Measures of Diagnostic Accuracy. 9.2.2 Detection of TAD Example. 9.2.3 The Mixed Effects ANOVA Model for Jackknife Pseudovalues. 9.2.4 Neonatal Examination Example. 9.2.5 A Bootstrap Method. 9.3 Sample Size Calculation for Multireader Studies. 10. Methods for Correcting Verification Bias. 10.1 A Single Binary Scale Test. 10.1.1 Correction Methods With the MAR Assumption. 10.1.2 Correction Methods Without the MAR Assumption. 10.1.3 Hepatic Scintigraph Example. 10.2 Correlated Binary Scale Tests. 10.2.1 An ML Approach Without Covariates. 10.2.2 An ML Approach With Covariates. 10.2.3 Screening Tests for Dementia Disorder Example. 10.3 A Single Ordinal Scale Test. 10.3.1 An ML Approach Without Covariates. 10.3.2 Fever of Uncertain Origin Example. 10.3.3 An ML Approach With Covariates. 10.3.4 Screening Test for Dementia Disorder Example. 10.4 Correlated Ordinal Scale Tests. 10.4.1 The Weighted GEE Approach for Latent Smooth ROC Curves. 10.4.2 A Likelihood Based Approach for ROC Areas. 10.4.3 Use of CT and MRI for Staging Pancreatic Cancer Example. 11. Methods for Correcting Imperfect Standard Bias. 11.1 One Single Test in a Single Population. 11.1.1 Hypothetical and Strongyloides Infection Examples. 11.2 One Single Test in G Populations. 11.2.1 Tuberculosis Example. 11.3 Multiple Tests in One Single Population. 11.3.1 MLEs Under the CIA. 11.3.2 Assessment of Pleural Thickening Example. 11.3.3 ML Approaches Without the CIA. 11.3.4 Bioassays for HIV Example. 11.4 Multiple Binary Tests in G Populations. 11.4.1 ML Approaches Under the CIA. 11.4.2 ML Approaches Without the CIA. 12. Statistical Methods for Meta Analysis. 12.1 Sensitivity and Specificity Pairs. 12.1.1 One Common SROC Curve. 12.1.2 Study Specific SROC Curve. 12.1.3 Evaluation of Duplex Ultrasonography, With and Without Color Guidance. 12.2 ROC Curve Areas. 12.2.1 Fixed Effects Models. 12.2.2 Random Effects Models. 12.2.3 Evaluation of the Dexamethasone Suppression.Test. Index.

Voriconazole compared with liposomal amphotericin B for empirical antifungal therapy in patients with neutropenia and persistent fever

Abstract: Background Patients with neutropenia and persistent fever are often treated empirically with amphotericin B or liposomal amphotericin B to prevent invasive fungal infections. Antifungal triazoles offer a potentially safer and effective alternative. Methods In a randomized, international, multicenter trial, we compared voriconazole, a new second-generation triazole, with liposomal amphotericin B for empirical antifungal therapy. Results A total of 837 patients (415 assigned to voriconazole and 422 to liposomal amphotericin B) were evaluated for success of treatment. The overall success rates were 26.0 percent with voriconazole and 30.6 percent with liposomal amphotericin B (95 percent confidence interval for the difference, –10.6 to 1.6 percentage points); these rates were independent of the administration of antifungal prophylaxis or the use of colony-stimulating factors. There were fewer documented breakthrough fungal infections in patients treated with voriconazole than in those treated with liposomal a...

Ventricular pacing or dual-chamber pacing for sinus-node dysfunction

Abstract: Background Dual-chamber (atrioventricular) and single-chamber (ventricular) pacing are alternative treatment approaches for sinus-node dysfunction that causes clinically significant bradycardia. However, it is unknown which type of pacing results in the better outcome. Methods We randomly assigned a total of 2010 patients with sinus-node dysfunction to dual-chamber pacing (1014 patients) or ventricular pacing (996 patients) and followed them for a median of 33.1 months. The primary end point was death from any cause or nonfatal stroke. Secondary end points included the composite of death, stroke, or hospitalization for heart failure; atrial fibrillation; heart-failure score; the pacemaker syndrome; and the quality of life. Results The incidence of the primary end point did not differ significantly between the dual-chamber group (21.5 percent) and the ventricular-paced group (23.0 percent, P=0.48). In patients assigned to dual-chamber pacing, the risk of atrial fibrillation was lower (hazard ratio, 0.79; 9...

Genetic Variation in the 6p22.3 Gene DTNBP1, the Human Ortholog of the Mouse Dysbindin Gene, Is Associated with Schizophrenia

Abstract: Prior evidence has supported the existence of multiple susceptibility genes for schizophrenia. Multipoint linkage analysis of the 270 Irish high-density pedigrees that we have studied, as well as results from several other samples, suggest that at least one such gene is located in region 6p24-21. In the present study, family-based association analysis of 36 simple sequence-length–polymorphism markers and of 17 SNP markers implicated two regions, separated by ∼7 Mb. The first region, and the focus of this report, is 6p22.3. In this region, single-nucleotide polymorphisms within the 140-kb gene DTNBP1 (dystrobrevin-binding protein 1, or dysbindin) are strongly associated with schizophrenia. Uncorrected, empirical P values produced by the program TRANSMIT were significant (P<.01) for a number of individual SNP markers, and most remained significant when the data were restricted to include only one affected offspring per nuclear family per extended pedigree; multiple three-marker haplotypes were highly significant (P=.008–.0001) under the restricted conditions. The pattern of linkage disequilibrium is consistent with the presence of more than one susceptibility allele, but this important issue is unresolved. The number of markers tested in the adjacent genes, all of which are negative, is not sufficient to rule out the possibility that the dysbindin gene is not the actual susceptibility gene, but this possibility appears to be very unlikely. We conclude that further investigation of dysbindin is warranted.

Salvinorin A: A potent naturally occurring nonnitrogenous κ opioid selective agonist

Abstract: Salvia divinorum, whose main active ingredient is the neoclerodane diterpene Salvinorin A, is a hallucinogenic plant in the mint family that has been used in traditional spiritual practices for its psychoactive properties by the Mazatecs of Oaxaca, Mexico. More recently, S. divinorum extracts and Salvinorin A have become more widely used in the U.S. as legal hallucinogens. We discovered that Salvinorin A potently and selectively inhibited 3H-bremazocine binding to cloned κ opioid receptors. Salvinorin A had no significant activity against a battery of 50 receptors, transporters, and ion channels and showed a distinctive profile compared with the prototypic hallucinogen lysergic acid diethylamide. Functional studies demonstrated that Salvinorin A is a potent κ opioid agonist at cloned κ opioid receptors expressed in human embryonic kidney-293 cells and at native κ opioid receptors expressed in guinea pig brain. Importantly, Salvinorin A had no actions at the 5-HT2A serotonin receptor, the principal molecular target responsible for the actions of classical hallucinogens. Salvinorin A thus represents, to our knowledge, the first naturally occurring nonnitrogenous opioid-receptor subtype-selective agonist. Because Salvinorin A is a psychotomimetic selective for κ opioid receptors, κ opioid-selective antagonists may represent novel psychotherapeutic compounds for diseases manifested by perceptual distortions (e.g., schizophrenia, dementia, and bipolar disorders). Additionally, these results suggest that κ opioid receptors play a prominent role in the modulation of human perception.

Nurse Moral Distress: a proposed theory and research agenda

Abstract: As professionals, nurses are engaged in a moral endeavour, and thus confront many challenges in making the right decision and taking the right action. When nurses cannot do what they think is right, they experience moral distress that leaves a moral residue. This article proposes a theory of moral distress and a research agenda to develop a better understanding of moral distress, how to prevent it, and, when it cannot be prevented, how to manage it.

Direct electron transfer of glucose oxidase on carbon nanotubes

Abstract: In this report, exploitation of the unique properties of single-walled carbon nanotubes (SWNT) leads to the achievement of direct electron transfer with the redox active centres of adsorbed oxidoreductase enzymes. Flavin adenine dinucleotide (FAD), the redox active prosthetic group of flavoenzymes that catalyses important biological redox reactions and the flavoenzyme glucose oxidase (GOx), were both found to spontaneously adsorb onto carbon nanotube bundles. Both FAD and GOx were found to spontaneously adsorb to unannealed carbon nanotubes that were cast onto glassy carbon electrodes and to display quasi-reversible one-electron transfer. Similarly, GOx was found to spontaneously adsorb to annealed, single-walled carbon nanotube paper and to display quasi-reversible one-electron transfer. In particular, GOx immobilized in this way was shown, in the presence of glucose, to maintain its substrate-specific enzyme activity. It is believed that the tubular fibrils become positioned within tunnelling distance of the cofactors with little consequence to denaturation. The combination of SWNT with redox active enzymes would appear to offer an excellent and convenient platform for a fundamental understanding of biological redox reactions as well as the development of reagentless biosensors and nanobiosensors.

A controlled trial of rasagiline in early Parkinson disease: The tempo study

Abstract: CONTEXT Monotherapy with rasagiline mesylate may be useful in early Parkinson disease (PD). OBJECTIVE To evaluate the safety and efficacy of the selective monoamine oxidase type B inhibitor rasagiline. DESIGN Multicenter, 26-week, parallel-group, randomized, double-blind, placebo-controlled clinical trial. SETTING Academically based movement disorders clinics. PATIENTS Patients with early PD not requiring dopaminergic therapy (n = 404). INTERVENTION Research participants were randomized to rasagiline mesylate at dosages of 1 mg or 2 mg per day or matching placebo. A 1-week escalation period was followed by a 25-week maintenance period. MAIN OUTCOME MEASURE The primary prespecified measure of efficacy was the change in the total Unified Parkinson's Disease Rating Scal score between baseline and 26 weeks of treatment, comparing each active treatment group with the placebo group. RESULTS Monotherapy with rasagiline was effective in this 26-week study. The adjusted effect size for the total Unified Parkinson's Disease Rating Scale was -4.20 units comparing 1 mg of rasagiline and placebo (95% confidence interval, -5.66 to -2.73 units; P<.001) and -3.56 units comparing a 2-mg dosage and placebo (95% confidence interval, -5.04 to -2.08 units; P<.001). There were no meaningful differences in the frequency of adverse events or premature withdrawals among the treatment groups. CONCLUSIONS Rasagiline is effective as monotherapy for patients with early PD. The 2 dosages in this trial were both effective relative to placebo. Further study is warranted to evaluate the longer-term effects of rasagiline in PD.

Continuing medical education and the physician as a learner: Guide to the evidence

Abstract: One faculty member in a professional school referred to continuing education as “shouting out of windows,” and an analysis of the programs at his institution shows the aptness of his metaphor: Faculty members who can be persuaded to do so give lectures on subjects of their own choosing to audiences they do not know, who have assembled only because they want to put in enough hours of classroom attendance so that they can meet a relicensure requirement. As a result, every profession now has members who vigorously oppose what they regard as the excessive promotion of continuing education. Cyril O. Houle, 1980 RESEARCHERS OF THE PAST DEcade produced systematic reviews of continuing medical education (CME) and other strategies intended to change physician behavior and improve patient outcomes. The subjects of the reviews included such concepts as audit and feedback, chart-based reminders, clinical practice guidelines, and formal lectures. Defined as interventions to change the behavior of physicians, the effects of those strategies were inconsistent across practitioners, settings, and behaviors. As a result, in the midst of contemporary discussions about quality improvement and the effects of continuing education, there is no singularly effective method for improving physician performance. Physicians must accept responsibility for their own continuous learning: setting goals and selecting educational activities to achieve those goals. We searched the Research and Development Resource Base in Continuing Medical Education and the Specialised Register of the Cochrane Effective Practice and Organization of Care group, supplemented by searches of MEDLINE from 1992 to February 2002 for systematic reviews and evidence of CME and its effect on both physicians and CME planners.

The many faces of emotional leadership

Abstract: This article focuses heavily on overviewing and analyzing the seven articles in this special issue on emotions and leadership. The articles are discussed in terms of four key leadership issues. The first issue concerns the traits necessary for leadership. Empathy is shown to be an important variable that is central to both emotional intelligence and leadership emergence. The second issue concerns the relationship of emotions to the leadership process. It is argued that a key leadership function is to manage the emotions of group members, especially with regard to feelings related to frustration and optimism. The third issue involves our perceptions about leaders. Leaders' emotional displays are demonstrated to have a larger impact on perceptions of leaders than the content of the leaders' messages, at least in some circumstances. The fourth area involves the relationship between leadership and performance. Leaders' influences upon emotional process variables are found to have a large impact on performance. The article develops several propositions that summarize the content of this special issue and, in addition, develops new propositions that suggest future areas of research. The article concludes by touching on the review process and acknowledges the reviewers for this special issue.

Depression scale scores in 8–17-year-olds: effects of age and gender

Abstract: Background: The excess of unipolar depression in females emerges in adolescence. However, studies of age effects on depression scale scores have produced divergent estimates of changes from childhood to adolescence. Method: We explored possible reasons for this discrepancy in two large, longitudinal samples of twins and singletons aged 8–17. Results: There were no differences between twins and singletons in their scores on the Short Mood and Feelings Questionnaire (SMFQ), a 13-item self-report depression scale. SMFQ scores for boys fell over this age-range, while those for girls fell from age 9 to age 11 and then increased from age 12 to age 17. The mean scores of girls under 12 and those 12 and over differed by only around one-fifth of a standard deviation. However, given the non-normal distribution of the scores, a cut point that selected the upper 6% of scores created the expected female:male ratio of 2:1. Conclusions: Implications for future research on adolescent depression are discussed.

Regulation of Cellular Differentiation in Filamentous Cyanobacteria in Free-Living and Plant-Associated Symbiotic Growth States

Abstract: Summary: Certain filamentous nitrogen-fixing cyanobacteria generate signals that direct their own multicellular development. They also respond to signals from plants that initiate or modulate differentiation, leading to the establishment of a symbiotic association. An objective of this review is to describe the mechanisms by which free-living cyanobacteria regulate their development and then to consider how plants may exploit cyanobacterial physiology to achieve stable symbioses. Cyanobacteria that are capable of forming plant symbioses can differentiate into motile filaments called hormogonia and into specialized nitrogen-fixing cells called heterocysts. Plant signals exert both positive and negative regulatory control on hormogonium differentiation. Heterocyst differentiation is a highly regulated process, resulting in a regularly spaced pattern of heterocysts in the filament. The evidence is most consistent with the pattern arising in two stages. First, nitrogen limitation triggers a nonrandomly spaced cluster of cells (perhaps at a critical stage of their cell cycle) to initiate differentiation. Interactions between an inhibitory peptide exported by the differentiating cells and an activator protein within them causes one cell within each cluster to fully differentiate, yielding a single mature heterocyst. In symbiosis with plants, heterocyst frequencies are increased 3- to 10-fold because, we propose, either differentation is initiated at an increased number of sites or resolution of differentiating clusters is incomplete. The physiology of symbiotically associated cyanobacteria raises the prospect that heterocyst differentiation proceeds independently of the nitrogen status of a cell and depends instead on signals produced by the plant partner.

RAGE and arthritis: the G82S polymorphism amplifies the inflammatory response.

Abstract: The receptor for advanced glycation end products (RAGE) and its proinflammatory S100/calgranulin ligands are enriched in joints of subjects with rheumatoid arthritis (RA) and amplify the immune/inflammatory response. In a model of inflammatory arthritis, blockade of RAGE in mice immunized and challenged with bovine type II collagen suppressed clinical and histologic evidence of arthritis, in parallel with diminished levels of TNF-alpha, IL-6, and matrix metalloproteinases (MMP) 3, 9 and 13 in affected tissues. Allelic variation within key domains of RAGE may influence these proinflammatory mechanisms, thereby predisposing individuals to heightened inflammatory responses. A polymorphism of the RAGE gene within the ligand-binding domain of the receptor has been identified, consisting of a glycine to serine change at position 82. Cells bearing the RAGE 82S allele displayed enhanced binding and cytokine/MMP generation following ligation by a prototypic S100/calgranulin compared with cells expressing the RAGE 82G allele. In human subjects, a case-control study demonstrated an increased prevalence of the 82S allele in patients with RA compared with control subjects. These data suggest that RAGE 82S upregulates the inflammatory response upon engagement of S100/calgranulins, and, thereby, may contribute to enhanced proinflammatory mechanisms in immune/inflammatory diseases.

Rethinking Democratic Accountability

Abstract: (2002) Rethinking Democratic Accountability Public Integrity: Vol 4, No 3, pp 269-272

Room-Temperature Synthesis and Characterization of Nanocrystalline CdS, ZnS, and CdxZn1-xS

Abstract: A novel and simple chemical reduction route at room temperature is described to synthesize nanocrystalline CdS, ZnS, and CdxZn1-xS. In the method, anhydrous CdCl2, or ZnCl2, S, and KBH4 powders react at room temperature in various organic solvents, and the effect of the solvent on the quality of the nanoparticle product is investigated. Among the solvents used, tetrahydrofuran is shown to produce the highest quality single-phase nanoparticles. The nanoparticles are characterized by X-ray diffraction, transmission electron microscopy, UV−vis absorption, and photoluminescence. The particle size ranges from 4 to 8 nm. In the CdxZn1-xS, the lattice structure gradually changes from cubic to hexagonal with increasing percentage of Zn in the ternary compound CdxZn1-xS. The nanoparticles exhibit broad emission peaks that shift to shorter wavelength with increasing percentage of Zn in the ternary compound CdxZn1-xS. The control of the composition of CdxZn1-xS nanoparticles may lead to the development of ideal mate...

Bupropion SR enhances weight loss: a 48-week double-blind, placebo- controlled trial.

Abstract: ANDERSON, JAMES W., FRANK L. GREENWAY, KENFUJIOKA, KISHORE M. GADDE, JAMES MCKENNEY,AND PATRICK M. O’NEIL. Bupropion SR enhancesweight loss: a 48-week double-blind, placebo-controlled trial.Obes Res. 2002;10:633–641.Objective: To critically examine the efficacy of bupropionSR for weight loss.Research Methods and Procedures: This 24-week multi-center, double-blind, placebo-controlled study randomizedobese adults to placebo, bupropion SR 300, or 400 mg/d.Subjects were counseled on energy-restricted diets, mealreplacements, and exercise. During a 24-week extension,placebo subjects were randomized to bupropion SR 300 or400 mg/d in a double-blinded manner.Results: Of 327 subjects enrolled, 227 completed 24 weeks;192 completed 48 weeks. Percentage losses of initial bodyweight for subjects completing 24 weeks were 5.0%, 7.2%,and 10.1% for placebo, bupropion SR 300, and 400 mg/d,respectively. Compared with placebo, net weight losseswere 2.2% (p 0.0468) and 5.1% (p 0.0001) for bupro-pion SR 300 and 400 mg/d, respectively. The percentages ofsubjects who lost 5% of initial body weight were 46%,59%, and 83% (p vs. placebo 0.0001) for placebo, bu-propion SR 300, and 400 mg/d, respectively; weight lossesof 10% were 20%, 33%, and 46% (p vs. placebo 0.0008) for placebo, bupropion SR 300, and 400 mg/d,respectively. Withdrawals, changes in pulse and blood pres-sure did not differ significantly from placebo at 24 weeks.Subjects who completed 48 weeks maintained mean lossesof initial body weight of 7.5% and 8.6% for bupropion SR300 and 400 mg/d, respectively.Discussion: Bupropion SR 300 and 400 mg/d were well-tolerated by obese adults and were associated with a 24-week weight loss of 7.2% and 10.1% and sustained weightlosses at 48 weeks.Key words: weight loss, pharmacotherapy, bupropionSR, lifestyle, pedometer, meal replacements

Traumatic brain injury induced cell proliferation in the adult mammalian central nervous system.

Abstract: Recent studies indicate the existence of progenitor cells and their potential for neurogenesis in the subventricular zone (SVZ) and the hippocampus of the normal adult mammalian brain. However, the proliferative response and the specific cell types generated following traumatic brain injury have not been examined. This cellular response to CNS injury was investigated using the fluid percussion injury (FPI) model, a widely accepted rat model that simulates moderate head injury sustained in humans. Forty-eight hours following moderate FPI, adult rats received intraperitoneal injections of the thymidine analogs, 5-bromodeoxyuridine (BrdU) or tritiated thymidine (3H-thymidine), which are markers for mitotic activity. Injured and control animals receiving BrdU were used to determine the total number of cells induced to proliferate. To determine the cellular identity of these proliferating cells, animals receiving 3H-thymidine were sacrificed and sections through the injured area were immunostained with markers for immature and mature astrocytes, activated microglia, neural precursors and mature neurons. These studies showed that the total number of proliferating cells was significantly increased in the injury group for both the SVZ and the hippocampus. However, the proliferating cells in the SVZ did not express any of the cellular markers used, suggesting that they have not yet begun to differentiate. In contrast, there was a significant increase in the number of immature astrocytes and activated microglia, but not neurons, at this early time point in the hippocampus. Taken together, these experiments demonstrate the compensatory capacity of the adult brain to injury and should lead to a new generation of studies aimed at enhancing the neuronal proliferative response.

Rationale for fixed-dose combinations in the treatment of hypertension: the cycle repeats

Abstract: Single-drug therapy remains the preferred way to begin treatment of hypertension, although in many patients this is unable to bring blood pressure (BP) to goal levels. Single-drug therapy, even when maximally titrated, is at best only modestly effective in normalising BP in Stage-I or II hypertension, which represents the majority of the hypertensive population. It is increasingly appreciated that the elusive goal of a ‘normal’ BP is achieved only if multi-drug therapy is employed. This is especially so when considered in the context of today’s lower BP goals. The options for multi-drug therapy are quite simple: either fixed-dose combination therapy or drugs added sequentially one after another to then arrive at an effective multi-drug regimen. Advocates exist for both approaches. A considerable legacy, dating to the 1950’s, exists for fixed-dose combination therapies. The rationale to this approach has remained constant. Fixed-dose combination therapy successfully reduces BP because two drugs, each typically working at a separate site, block different effector pathways. In addition, the second drug of such two-drug combinations may check counter-regulatory system activity triggered by the other. For example, a diuretic and β-blocker combination may find the diuretic correcting the salt-and-water retention which occasionally accompanies β-blocker therapy. The pattern of adverse effects also differs with fixed-dose combination therapy, in part, because less drug is generally being given. In addition, one component of a fixed-dose combination therapy can effectively counterbalance the tendency of the other to produce adverse effects. For example, the peripheral oedema, that accompanies calcium channel antagonist therapy, occurs less frequently when an ACE inhibitor is co-administered. ACE inhibitors improve, if not eliminate, the peripheral oedema associated with calcium channel antagonists because of their proven ability to cause venodilation. In addition, diuretic therapy-induced volume contraction may generate a state of secondary hyperaldosteronism and thereby electrolyte abnormalities such as hypokalaemia and/or hypomagnesaemia. In many cases, the co-administration of either an ACE inhibitor or an angiotensin II receptor blocker with a diuretic corrects the aforementioned electrolyte disturbances. Fixed-dose combination therapy has a proven record of reducing BP. This form of treatment has been available for close to a half-century. Over that period of time, many physicians have taken advantage of this therapeutic approach even when academic opinion was less than charitable to this concept. Academic opinion is rarely immutable and occasionally irrelevant to prescription practice. Prescription practice is driven by many considerations including ease of use, cost and tolerance of a therapy. Most importantly, the therapeutic pathway taken should successfully result in goal BP being reached in a large number of those treated. Unfortunately, despite the simplicity of the concept behind fixed-dose combination therapy, its success will ultimately rest on cost. If made truly cost-competitive, it will gain an increasing share of the hypertensive market. If not, market forces will relegate it to a secondary role for hypertension treatment.

Use of Emergency Medical Services in Acute Myocardial Infarction and Subsequent Quality of Care Observations From the National Registry of Myocardial Infarction 2

Abstract: Background— National practice guidelines strongly recommend activation of the 9-1-1 Emergency Medical Systems (EMS) by patients with symptoms consistent with an acute myocardial infarction (MI). We examined use of the EMS in the United States and ascertained the factors that may influence its use by patients with acute MI. Methods and Results— From June 1994 to March 1998, the National Registry of Myocardial Infarction 2 enrolled 772 586 patients hospitalized with MI. We excluded those who transferred in, arrived at the hospital >6 hours from symptom onset, or who were in cardiogenic shock. We compared baseline characteristics and initial management for patients who arrived by ambulance versus self-transport. EMS was used in 53.4% of patients with MI, a proportion that did not vary significantly over the 4-year study period. Nonusers of the EMS were on average younger, male, and at relatively lower risk on presentation. In addition, payer status was significantly associated with EMS use. Use of EMS was in...

Empathy and complex task performance: two routes to leadership

Abstract: When we perceive someone as a leader, it is often because we are impressed with his/her mental abilities and his/her ability to perform complex tasks. Yet, there is a small but growing body of conceptual work suggesting that our perception of someone as a leader is affected by his/her emotional abilities as well. This article develops a model proposing two distinct behavioral routes that influence perception of an individual as a leader in a small group. One route influences people to perceive leadership from displays of emotional abilities, such as empathy. The other route influences people to perceive leadership from displays of mental abilities, such as complex task performance. Our test of the hypothesized model using structural equation modeling showed a good fit and support for the proposed relationships.

Migrant Housing in Urban China: Choices and Constraints

Abstract: China’srecent waves of internal migration, primarily rural to urban, reflect a rapidly urbanizing society undergoing a transition from a planned to a market economy. The author addresses two key questions: what access migrants have to urban housing and how migrant housing conditions compare with those of the locals. The main findings are based on citywide housing surveys and interviews conducted in Shanghai and Beijing, as well as results from official surveys. Interpretations of migrant housing patternsin urban China need to be linked with the country’sunique institutional factors, particularly the circulating nature of migration, the existing household registration system, and the transitioning state of the urban housing market. Restricted access to urban housing, together with the temporary status for migrants, contributes to their poor housing conditions.

Elementary Teachers' Classroom Assessment and Grading Practices

Abstract: The authors investigated the assessment and grading practices of over 900 Grades 3-5 teachers representing urban, suburban, and rural schools. Teachers indicated the extent to which they used various factors to grade students, the types of assessments used, the cognitive level of assessments, and the grades awarded. Teachers appeared to conceptualize 6 major factors when they graded students; they placed the greatest weight on academic performance and academic-enabling behaviors, such as effort and improvement, and much less emphasis on homework, comparisons with other students, grade distributions of other teachers, and borderline cases. The teachers used 3 types of assessments—constructed-response, objective, and teacher-made major examinations; they differentiated between recall and higher level cognitive skills. However, there were few relationships between assessment and grade level, subject matter assessed, and grades awarded. Results are discussed in light of other research, indicating tha...