Empirical developments in retraction.

This study provides current data on key questions about retraction of scientific articles. Findings confirm that the rate of retractions remains low but is increasing. The most commonly cited reason for retraction was research error or inability to reproduce results; the rate from research misconduct is an underestimate, since some retractions necessitated by research misconduct were reported as being due to inability to reproduce. Retraction by parties other than authors is increasing, especially for research misconduct. Although retractions are on average occurring sooner after publication than in the past, citation analysis shows that they are not being recognised by subsequent users of the work. Findings suggest that editors and institutional officials are taking more responsibility for correcting the scientific record but that reasons published in the retraction notice are not always reliable. More aggressive means of notification to the scientific community appear to be necessary.

Beta-adrenergic receptor gene polymorphisms and hemodynamic response to dobutamine during dobutamine stress echocardiography.

Our objective was to determine if beta(1)-adrenergic receptor (beta(1)-AR) and beta(2)-AR gene polymorphisms influence heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) response to dobutamine during dobutamine stress echocardiography (DSE). Patients (n=163) undergoing clinically indicated DSE were enrolled. Dobutamine doses were titrated from 5 to 40 microg kg(-1) min(-1) at 3 min intervals and HR, SBP and DBP were measured. Genotypes were determined for beta(1)-AR Ser49Gly, beta(1)-AR Arg389Gly, beta(2)-AR Arg16Gly and beta(2)-AR Gln27Glu polymorphisms by polymerase chain reaction-restriction fragment length polymorphism analysis, pyrosequencing and single primer extension methods. beta(2)-AR Glu27 homozygotes had a greater HR response at the highest dobutamine dose than Gln27 carriers (P=0.002). Beta(2)-AR Gly16 homozygotes had a lower HR response during 5-30 microg kg(-1) min(-1) of the dobutamine infusion protocol compared to Arg16 carriers (P=0.03). Differences in SBP by beta(2)-AR codon 16 genotype and DBP by beta(1)-AR codon 389 genotype were found at baseline and were maintained throughout DSE (P=0.06 and 0.02, respectively). However, the magnitude of SBP and DBP response to dobutamine did not differ significantly by beta(2)-AR codon 16 or beta(1)-AR codon 389 genotypes, respectively. These data suggest that the four selected beta(1)- and beta(2)-AR polymorphisms do not substantially influence the magnitude of hemodynamic response to dobutamine during DSE.

Association of CYP3A5 polymorphisms with hypertension and antihypertensive response to verapamil.

In the CYP3A5 gene, the A>G (*3) and G>A (*6) polymorphisms result in severely decreased expression of CYP3A5 enzyme relative to a normal functional allele (*1). We sought to determine if the CYP3A5 genetic polymorphisms were associated with level of blood pressure (BP), risk of hypertension (HTN), and the antihypertensive response to verapamil. A total of 676 normotensive and hypertensive participants (mean age 49+/-8.2 years) from the Hypertension Genes study and 722 patients (mean age 66+/-9 years) from the International Verapamil/Trandolapril Study Genetic Substudy (INVEST-GENES) were genotyped for CYP3A5 to test for associations with BP, HTN, and in the latter cohort, antihypertensive response to verapamil. CYP3A5 haplotypes were determined using PHASE 2, with any allele containing either (*3) or (*6) designated as non functional. In the HTN genes population, there were no significant differences based on the number of functional CYP3A5 alleles, in systolic blood pressure (SBP) or diastolic blood pressure (DBP) among the normotensive whites or blacks (all P> or =0.70) or in allele frequency between normotensives and hypertensives. In INVEST-GENES, when controlled for baseline BP, race, age, and gender, untreated BP in carriers versus non carriers of a CYP3A5 functional allele was 158.2+/-13.7 and 154.8+/-13.7 (P=0.061), respectively. CYP3A5 functional allele status was marginally associated with the SBP response to verapamil in blacks (P=0.075) and Hispanics (P=0.056), but not in whites (P=0.40), with the effect being largely driven by higher SBP in the carriers of two functional alleles. There was no association with DBP response and CYP3A5 allele status. CYP3A5 genotype does not contribute importantly to BP or risk of HTN, but may influence response to calcium channel blockers in populations in which carrier status of two functional alleles is common.

Influence of phenotype and pharmacokinetics on beta-blocker drug target pharmacogenetics.

Two common polymorphisms in the beta1-adrenergic receptor gene, Ser49Gly and Arg389Gly, are associated with variable antihypertensive response to metoprolol. We sought to determine whether similar pharmacogenetic associations were present with the negative chronotropic response phenotype to metoprolol. Metoprolol was titrated in 54 untreated hypertensive patients to achieve blood pressure control. We found no association between either resting or exercise heart rate at baseline (untreated) or in response to metoprolol by codon 389 genotype. In contrast, when compared by codon 49 genotype, Ser49 homozygotes had significantly higher resting heart rates at baseline (untreated) than Gly49 carriers (82+/-10 versus 74+/-11 bpm, respectively, P=0.016). When corrected for plasma concentration, we found no difference in reduction in exercise heart rate in response to metoprolol between Ser49 homozygotes and Gly49 carriers (0.75+/-0.11 versus 0.57+/-0.17%/ng/ml, respectively, P=0.37). However, if one fails to account for plasma concentration, trends toward a significant difference in heart rate reduction are seen between Ser49 homozygotes and Gly49 carriers (31% reduction versus 25% reduction, P=0.05). Our data suggest that neither the beta1-adrenergic receptor Arg389Gly, nor the Ser49Gly polymorphisms are associated with variable negative chronotropic response to metoprolol. In addition, our data highlight the importance of measuring metoprolol concentration in order to account for variable pharmacokinetics and avoid misinterpretation of the data.

Cardiovascular function during cognitive stress in men before and after coronary artery bypass grafts.

Cardiovascular function during cognitive stress using the Stroop Color Test (SCWT) was documented in 25 men with ischemic heart disease (IHD) before and after coronary artery bypass grafting (CABG). Impedance cardiography was used to measure changes from resting baseline in heart rate (HR), stroke volume (SV), cardiac output (CO), myocardial contractility, and total peripheral resistance (TPR). Cognitive stress was associated with significant increases in HR, blood pressure, SV, CO, and myocardial contractility. TPR did not change from resting baseline during cognitive stress before CABG. However, TPR decreased significantly from resting baseline during cognitive stress after CABG. These findings support the theory that cognitive stress is associated with a significant increase in myocardial oxygen demand.

Hypothesis testing.

Hypothesis testing is the process of making a choice between two conflicting hypotheses. The null hypothesis, H0, is a statistical proposition stating that there is no significant difference between a hypothesized value of a population parameter and its value estimated from a sample drawn from that population. The alternative hypothesis, H1 or Ha, is a statistical proposition stating that there is a significant difference between a hypothesized value of a population parameter and its estimated value. When the null hypothesis is tested, a decision is either correct or incorrect. An incorrect decision can be made in two ways: We can reject the null hypothesis when it is true (Type I error) or we can fail to reject the null hypothesis when it is false (Type II error). The probability of making Type I and Type II errors is designated by alpha and beta, respectively. The smallest observed significance level for which the null hypothesis would be rejected is referred to as the p-value. The p-value only has meaning as a measure of confidence when the decision is to reject the null hypothesis. It has no meaning when the decision is that the null hypothesis is true.

Factor analysis of the Ways of Coping Questionnaire for African American women.

The purpose of this study was to determine the factorial structure of the Ways of Coping Questionnaire for African American women. A sample of 656 African American women living in the southeastern United States, ranging in age from 22 to 64 years (M = 39.6 years), completed the questionnaire. All were employed, with a mean annual income of $24,300. Factor analysis produced three factors, Active Coping, Avoidance, and Minimize the Situation, that accounted for 67% of the total variance. These factors were compared with the eight factors of the Ways of Coping questionnaire reported by Folkman and Lazarus (1980), which was derived from a sample of middle-aged White subjects. The factors that emerged suggest the need for possible revision of the instrument or the development of a new one.

Physiologic response to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension.

BACKGROUND: Endotracheal suctioning may cause sudden increases in pulmonary arterial pressure, which can result in hypoxia secondary to right ventricular failure and/or increased right-to-left shunting. An adaptor that allows suctioning without disconnecting the ventilator has been proposed to prevent these problems; however, its efficacy has not been rigorously studied. OBJECTIVE: To examine the physiologic responses to two endotracheal suctioning techniques in newborn lambs with and without acute pulmonary hypertension. METHODS: A repeated-measures design was used to compare two endotracheal suctioning techniques in seven newborn lambs with and without acute pulmonary hypertension. An adaptor was used in the ventilator-controlled technique, making disconnection of the ventilator during suctioning unnecessary. In the bag-controlled technique, the ventilator was disconnected and ventilation was done with a manual resuscitation bag. Physiologic variables, pulmonary and mean arterial pressure, peak inspiratory pressure, mixed venous oxygen saturation, cardiac index, and arterial blood gas values were recorded before, during, and after endotracheal suctioning. RESULTS: Endotracheal suctioning caused a statistically significant systemic hypertensive response in lambs with and without acute pulmonary hypertension, regardless of which suctioning technique was used. No statistically significant changes occurred in pulmonary arterial pressure using either technique. CONCLUSIONS: Use of an adaptor resulted in no differences in the physiologic responses to endotracheal suctioning. However, endotracheal suctioning was easier to perform using an adaptor because no extra equipment or person was needed.

Relative risk of untreated hypertension in type-A employed African American women.

The purpose of this study was to determine the relative risk of hypertension in African American women with type A behaviour pattern. Of the 305 employed African American women, 147 (48.2%) were classified as type A and 158 (51.8%) as type B. The logistic regression procedure was used to calculate the adjusted relative risk of having an elevated SBP by controlling for age, weight and cholesterol. We found that the adjusted relative risk of type A African American women having an elevated SBP and DBP was 9.06 and 2.26 times that of type B, respectively.

Predictors of burnout in critical care nurses.

OBJECTIVE: To develop a conceptual path model to explain the effects of a set of personal and occupational independent variables and the dependent variables of situational stress, job stress, job satisfaction, and job motivation on burnout among critical care nurses. DESIGN: A prospective descriptive study using a conceptual path model. SETTING: Nine hospitals in the northeastern, northwestern, north central, and southern regions of Florida. SAMPLE: Three hundred female critical care nurses employed in the nine hospitals who had worked full-time for at least 3 months. INSTRUMENTS: Subjects were administered a demographic and work survey instrument, the Daily Hassles Instrument, the Psychological Hardiness Test, the Job Diagnostic Inventory, and the Maslach Burnout Inventory. RESULTS: Path analysis of a burnout model resulted in a causal progression of situational stress, job stress, job satisfaction, and emotional exhaustion (which is a component of burnout). The results showed that commitment to career, health difficulties, psychologic hardiness, work load satisfaction, dealing with others at work, job security, and job satisfaction had a significant effect on emotional exhaustion. CONCLUSION: Seven variables had a significant effect on emotional exhaustion, which is a component of burnout, and explained 34% of the variance. The three most significant effects on emotional exhaustion were commitment to career, dealing with others at work and job satisfaction. Health difficulties, psychologic hardiness, work load satisfaction, and job security had a modest effect on emotional exhaustion.

Job satisfaction among critical care nurses.

OBJECTIVE: To develop a conceptual path model to explain the effects of a set of personal and work-related independent variables and the dependent variables of situational stress, job stress and job motivation on job satisfaction among critical care nurses. DESIGN: A prospective descriptive study using a conceptual path model. SETTING: Nine hospitals licensed for at least 250 beds in the northeastern, northwestern, northcentral, and southern regions of Florida. SAMPLE: Three hundred female critical care nurses employed in the nine hospitals who had worked full-time for at least 3 months. MEASUREMENTS: Subjects were administered a demographic and work survey questionnaire, Daily Hassles Instrument, Psychological Hardiness Test and the Job Diagnostic Inventory. MAIN OUTCOME MEASURES: A conceptual path model was constructed to illustrate the effects of a set of personal and work-related independent variables and the dependent variables of situational stress, job stress and job motivation on job satisfaction. MAIN RESULTS: Path analysis of a job satisfaction model resulted in a causal progression of situational stress leading to either job stress or job motivation, both affecting job satisfaction. The results showed that job stress, job motivation, job expectations, meaningful work, knowledge of work results, commitment to career, health difficulties, task identity, supervision, dealing with others at work, opportunity for advancement, pay and job security had a significant effect on job satisfaction. CONCLUSION: Thirteen variables had a significant effect on job satisfaction and explained 63% of the variance. The four most significant effects on job satisfaction were opportunities for advancement, meaningfulness of work, pay and supervision. Commitment to the career, task identity and job security had a modest effect on job satisfaction.

A path model of type A and type B responses to coping and stress in employed black women.

The purpose of this study was to test a conceptual model of the effects of age, weight, type, cholesterol, systolic blood pressure, and coping on the stress response of southern black women. Data were collected on 280 employed black women. Audiotape analyses of the structured interview resulted in 136 Type A's and 144 Type B's. Each individual was screened for hypercholesteremia using a portable reflectance photometer. Blood pressure measurements were taken every minute before, during, and after a stress-producing Type A/B interview. Type A's had higher resting systolic blood pressures, higher cholesterol levels, higher levels of stress during the interview, and lower coping scores than Type B's. The relationships between age, weight, and resting systolic blood pressures all were in the direction reported in the literature.

Institutionalized elderly. Relaxation, locus of control, self-esteem.

Progressive relaxation significantly moved elders toward a perception of internal locus of control. Progressive relaxation and activity programs significantly increased elders' self-esteem. Progressive relaxation was significantly more effective than the activity group in increasing self-esteem. Changes in locus of control and self-esteem were not correlated.

Type A/B behaviors in employed black women: comparison of blood pressures and cholesterol levels.

The purpose of this study was to examine the difference in mean blood pressure and mean cholesterol levels between Type A/B employed Black women. Data were collected on age (mean 38.76 years), weight (mean 179.28 pounds), cholesterol (mean 194.45 mg/dL), systolic blood pressures before (mean 130.68 mm Hg), during (mean 138.81 mm Hg), and after (mean 129.98 mm Hg), and diastolic blood pressure before (mean 77.11 mm Hg), during (mean 81.45 mm Hg), and after (mean 76.20 mm Hg) the Type A Structured Interview (SI) on 280 employed Black women. Audio tape analyses of the SI resulted in 136 Type A's and 144 Types B's. Each individual was screened for hypercholesteremia using a portable reflectance photometer. Blood pressure measurements were taken every minute during administration of the SI. The results indicated that Type A's had higher mean systolic blood pressures, higher diastolic blood pressures before, during and after a structured interview, and higher cholesterol levels than Types B's.