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Retinoids reverse the abnormal pattern of keratinization seen in acne vulgaris. Tazarotene is the first of a novel family of topical receptor-selective acetylenic retinoids. This study evaluates the safety and efficacy of topical tazarotene 0.1% and 0.05% gels, in comparison to vehicle gel, applied once daily for 12 weeks, in the treatment of mild-to-moderate facial acne vulgaris. A total of 446 patients with facial acne vulgaris were enrolled, and 375 patients, ranging in age from 14 to 44 years, were evaluable in this multicenter, double-blind, randomized study. In comparison to vehicle gel, treatment with tazarotene 0.1% gel resulted in significantly greater reductions in noninflammatory and total lesion counts at all follow-up visits, and inflammatory lesion counts at Week 12. Tazarotene 0.05% gel resulted in significantly greater reductions in noninflammatory and total lesion counts than vehicle gel at Weeks 8 and 12. At Week 12, treatment success rates were 68% and 51% for tazarotene 0.1% and 0.05%, respectively (40% for vehicle gel). Tazarotene gel was an effective, safe, and generally well-tolerated therapy for the treatment of acne vulgaris.

Objective: Myocardial metabolic requirements during reperfusion of ventricular fibrillation are poorly understood. The objective of this study was to determine if controlled reperfusion after a clinically relevant global ischemia period of 10 mins was sufficient to prevent or reverse myocardial ischemia as indicated by changes in myocardial high energy phosphates, myocardial intracellular pH, and great cardiac vein lactate., Design: Prospective laboratory study with controlled reperfusion., Setting: Research laboratory at a university medical center., Subjects: Five swine weighing 19 +/- 3 kg., Interventions: Ten minutes of nonperfused ventricular fibrillation followed by reperfusion with cardiopulmonary bypass (flow 30 mL/kg/min) for 50 mins., Measurements and Main Results: Myocardial adenosine triphosphate (ATP), phosphocreatine, and intracellular pH were determined using in vivo 31P nuclear magnetic resonance. Myocardial blood flow, measured by 15-mu radiolabeled microspheres, was significantly increased above baseline during reperfusion. Phosphocreatine was depleted during the 10 mins of nonperfused ventricular fibrillation, but recovered to 122 +/- 18% of baseline with reperfusion and was 112 +/- 18% at 60 mins (p < .005). ATP concentrations decreased to 51 +/- 16% of baseline after 10 mins of nonperfused ventricular fibrillation, improved to 67 +/- 9% of baseline with early reperfusion, and were 65 +/- 9% of baseline at 60 mins (p < .02). Myocardial intracellular pH improved from 6.11 +/- 0.18 after 10 mins of nonperfused ventricular fibrillation, to 6.89 +/- 0.20 with early reperfusion, and then decreased to 6.85 +/- 0.35 at 60 mins ventricular fibrillation (p < .001). Despite myocardial blood flows higher than baseline during the reperfusion period, great cardiac vein/aortic lactate gradient increased over the reperfusion period., Conclusion: Prolonged reperfusion with supranormal myocardial blood flow does not restore normal myocardial aerobic metabolism in the fibrillating myocardium after a 10-min nonperfused ventricular fibrillation period.

Single and dual radionuclide techniques have been described in localization of parathyroid adenomas. Although single radionuclide imaging with Tc-99m sestamibi has many advantages, it can fail to demonstrate a parathyroid adenoma, which, in the case presented, is well demonstrated with dual radionuclide imaging. The authors recommend dual tracer imaging when searching for parathyroid adenoma.

Objective: To determine the effect of magnesium administration on aortic, right atrial and coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR)., Design: Twelve swine weighing 23.2 +/- 3.1 kg were instrumented for CPP, aortic systolic (AOSP) and aortic diastolic (AODP) pressures., Intervention: Ventricular fibrillation was induced and after 20 min of CPR the animals were allocated to receive epinephrine 0.2 mg/kg, or epinephrine 0.2 mg/kg plus magnesium 0.14 g/kg. Epinephrine was repeated every 5 min. Arterial blood gases were determined during normal sinus rhythm and prior to drug administration., Results: Pressures were recorded and averaged over four consecutive 5-min intervals following initial drug administration. AOSP, AODP and CPP were compared using an analysis of covariance. AOSP was statistically lower in the group receiving magnesium. There was a trend toward lower AODP and CPP in the group receiving magnesium as well. These statistical differences and trends were absent after adjusting for pressures during normal sinus rhythm and serum bicarbonate prior to drug administration., Conclusions: In this model of prolonged cardiac arrest, the administration of magnesium with epinephrine appeared to have a negative effect on aortic pressures during CPR. Further study is needed to determine the confounding effect of serum bicarbonate on the response to epinephrine and magnesium during CPR.

Study Hypothesis: Previous studies have not discerned the best method for generating regional cerebral blood flow during internal cardiac massage. We hypothesized that regional cerebral blood flow generated by a mechanical method--direct mechanical ventricular assistance (DMVA)--would be superior to manual internal cardiac massage (MAN)., Study Population: Twelve adult Yucatan minipigs weighing more than 44 kg each were studied., Methods: Swine were instrumented for regional cerebral blood flow measurements using tracer microspheres. After 15 minutes of ventricular fibrillation, swine were randomized to receive either MAN or DMVA. Regional cerebral blood flow was measured during normal sinus rhythm and at one minute (VF-1) and six minutes (VF-2) after initiation of circulatory support. Regional cerebral blood flow values were compared using a Wilcoxon rank sum test., Results: During VF-1, there was a tendency for DMVA to produce greater regional cerebral blood flow than MAN, although these differences were not statistically significant (DMVA vs MAN as mL/min/100 g): cerebral cortex, 28 versus 11; cerebellum, 49 versus 22; midbrain, 43 versus 16; pons, 55 versus 18; medulla, 55 versus 19; and spinal cord, 33 versus 10. During VF-2, DMVA produced greater regional cerebral blood flows than were produced by MAN: cerebral cortex, 39 versus 12 (P less than .06); cerebellum, 58 versus 20 (P less than 0.5); midbrain, 50 versus 18 (P less than .05); pons, 52 versus 22 (P less than .06); medulla, 53 versus 20 (P less than .05); and spinal cord, 31 versus 12 (P less than .05)., Conclusion: DMVA produces greater regional cerebral blood flow than is produced during MAN after 15 minutes of ventricular fibrillation. DMVA is effective at maintaining regional cerebral blood flow after a prolonged cardiac arrest.

Study Hypothesis: Current American Heart Association guidelines recommend immediate defibrillation of ventricular fibrillation. When this is unsuccessful, there are no guidelines to help determine the optimum time at which to defibrillate after the administration of an alpha-adrenergic agonist. Previous studies have shown that the median frequency of the ventricular fibrillation ECG signal correlates with myocardial perfusion during CPR. We hypothesized that median frequency could predict the success of defibrillation and thus accurately determine the most appropriate time at which to defibrillate during ventricular fibrillation., Study Population: Twenty-two mixed-breed swine weighing more than 15 kg were studied., Methods: Ventricular fibrillation was induced electrically, and the ventricular fibrillation ECG signal was analyzed using fast Fourier analysis. After ten minutes of ventricular fibrillation, mechanical CPR was begun. After three minutes of CPR, the animals received one of three alpha-adrenergic agonists and CPR was continued. Defibrillation was attempted three and one-half minutes after drug administration. The average median frequency 20 seconds before defibrillation was calculated. Sensitivity and specificity of median frequency with respect to defibrillation success were determined., Results: A median frequency of 9.14 Hz had a sensitivity of 100% and a specificity of 92.31% in predicting the results of defibrillation in this model., Conclusion: The median frequency may serve as a valuable parameter to guide defibrillation therapy during ventricular fibrillation.