2,3-Butanedione monoxime preserves coronary artery endothelium-dependent relaxation during myocardial ischemia in the isolated rat heart.

OBJECTIVE: To evaluate the potential benefit of 2,3-butanedione monoxime (BDM) in preserving endothelium-dependent coronary artery relaxation during myocardial ischemia. MATERIALS AND METHODS: Langendorff-perfused rat heart model. Endothelium-dependent and independent relaxations were tested with infusion of 5-hydroxytryptamine (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L), respectively. Four groups of hearts (n = 6) were used. Group 1 was perfused with BDM (25 mmol/L) without ischemia for 30 mins. Group 2 was perfused for 10 mins with BDM and exposed to 30 mins of no flow ischemia (37 degrees C). Group 3 was perfused with cold (4 degrees C) nonoxygenated BDM (30 mins) and group 4 (control) was exposed to 30 mins of no flow ischemia alone. Left ventricular pressure (LVP), left ventricular pressure first derivative (dP/dt) and coronary basal flow were evaluated before treatment and after 30 mins of reperfusion. RESULTS: BDM perfusion alone (group 1) did not affect coronary reactivity. Preservation of endothelium-dependent and -independent relaxation was significantly enhanced after ischemia in groups 2 and 3 (BDM-treated) compared with group 4 (control). No significant benefit was found regarding LVP and dP/dt in all groups. Postreperfusion coronary flow was decreased in all hearts except the controls (group 4), suggesting a residual BDM intrinsic effect on coronary flow. CONCLUSION: These experiments suggest that BDM can enhance preservation of coronary artery endothelium-dependent and -independent relaxation during myocardial ischemia in the isolated rat heart.

[A method for validating a translated questionnaire]. / Une méthode pour faire valider la traduction d'une questionnaire.

This paper describes Haccoun's (1987) technique for validating a translated questionnaire. This method is based on the idea that if a questionnaire is well translated, bilingual subjects will provide equivalent responses to questions in either language. A single group of bilingual subjects is given both language versions of the questionnaires at two different times in random order. Subsequently: 1) test-retest reliability coefficients are computed for the original and translated versions; 2) correlation coefficients between the original and translated versions of the instrument are computed and compared (simultaneous correlations between languages); 3) the correlations between the original version at time 1 and the translated version at time 2 and vice versa are computed and compared (cross-correlations); and 4) the cross-correlations are compared to the test-retest reliabilities within each language. The final step indicates whether the translated version of the instrument is equivalent to the original. The authors use Haccoun's technique to demonstrate that a French translated version of Alcock et al.'s (1990) questionnaire on nurses' perceptions of nursing research is reliable and statistically equivalent to the original.

Predictive model to determine cost/benefit of early detection and intervention in occupational low back pain.

Low back pain related to work injury has major socioeconomic implications. Theoretically, the early detection of patients at risk for continued work disability after 6 months of work absence, and of those with a recurrence of pain (RP) and leave work once again, should be cost-effective if combined with effective intervention. The objective of this prospective research was to analyze the cost-effectiveness of a detection-intervention system (DIS) developed from a logistic predictive model of work status. A sample of newly injured workers (N=135 males) were assessed following a first episode of compensated low back pain. A predictive biopsychosocial profile was obtained from a series of univariate and multivariate regression analyses. Structural diagnosis, pain rating, length of inactivity before treatment, negative life changes, and self-efficacy expectancies were found to be best predictors. With a correct classification rate of 72% the predictive model parameters (sensitivity and specificity) were chosen in order to reduce the number of false negatives (recurrence of pain or chronic patients not detected). The calculation of the cost/benefit proportions reveals that the detection-intervention system generates savings of up to $39,595 Can./100 patients a year. By combining low treatment expenses ($250 Can to $1,000 Can.) and increasing the success rates (40-75% return to work), the detection-intervention system is potentially more cost effective than the current approach without detection-intervention.

Influence of leukopenia on collateral flow, reperfusion flow, reflow ventricular fibrillation, and infarct size in dogs.

Leukocytes contribute to myocardial damage during ischemia and reperfusion. However, the mechanism involved has not been clearly elucidated. The purpose of the present study was to determine whether leukocyte-induced myocardial damage is flow mediated. In open-chest dogs submitted to 2 hours of ischemia, area at risk, infarct size, and regional myocardial blood flow before, during, and after ischemia were measured. Leukopenia was induced by a two-step method (chemotherapy and antineutrophil serum) in a group of 14 dogs as compared to a control group of 18 dogs. The relation of infarct size to the major determinants of infarct size was analyzed by uni- and multilinear regressions. Seven control dogs had ventricular fibrillation at reperfusion compared to one dog with leukopenia. In the group with leukopenia the mean infarct size was smaller (31.1 +/- 5.8% of area at risk) than in the control group (47.7 +/- 2.9, p = 0.02). In addition, the two multiple linear regression equations were significantly different (p = 0.01). Myocardial blood flow to the central ischemic zone did not change significantly between 20 and 120 minutes of ischemia in the control dogs (n = 12; subendocardial = 0.08 +/- 0.03 vs 0.07 +/- 0.03 ml/min/gm; subepicardial = 0.20 +/- 0.07 vs 0.20 +/- 0.05 ml/min/gm) and in the dogs with leukopenia (n = 12; 0.07 +/- 0.02 vs 0.07 +/- 0.02 ml/min/gm and 0.15 +/- 0.004 vs 0.18 +/- 0.04 ml/min/gm). A similar reduction in myocardial blood flow was observed after 6 hours of reperfusion in the control dogs (0.34 +/- 0.07 ml/min/gm vs 1.02 +/- 0.11 at baseline, p less than 0.01) and in the dogs with leukopenia (0.25 +/- 0.04 vs 0.81 +/- 0.08 ml/min/gm, p less than 0.01). It was concluded that the leukocyte-dependent myocardial injury did not appear to be mediated through a flow mechanism during either ischemia or reperfusion.

Late thrombosis of saphenous vein coronary bypass grafts related to risk factors.

In 72% of 143 patients undergoing a second coronary bypass grafting, mural or occlusive late thrombosis was observed histologically in 69% of 173 resected grafts. Late thrombosis was particularly prevalent in atherosclerotic grafts (80.2% vs. 40.4% in nonatherosclerotic grafts) and was always noted in 16 grafts with aneurysmal dilation. Multivariate analysis of risk factors contributing to late thrombosis indicated that graft atherosclerosis and smoking after graft surgery played important roles. Univariate analysis also showed significantly higher ratios of serum total cholesterol/HDL cholesterol and of serum LDL cholesterol/HDL cholesterol in patients whose grafts were affected by late thrombosis. To prevent late thrombosis of saphenous vein aortocoronary grafts, it appears reasonable that decreasing the ratios of total cholesterol/HDL cholesterol and of LDL cholesterol/HDL cholesterol, refraining from smoking, and controlling other risk factors for atherosclerosis should be advised.