Demonstration of Scale-Invariant Rayleigh-Taylor Instability Growth in Laser-Driven Cylindrical Implosion Experiments.

Rayleigh-Taylor instability growth is shown to be hydrodynamically scale invariant in convergent cylindrical implosions for targets that varied in radial dimension and implosion timescale by a factor of 3. The targets were driven directly by laser irradiation providing a short impulse, and instability growth at an embedded aluminum interface occurs as it converges radially inward by a factor of 2.25 and decelerates on a central foam core. Late-time growth factors of 14 are observed for a single-mode m=20 azimuthal perturbation at both scales, despite the differences in laser drive conditions between the experimental facilities, consistent with predictions from radiation-hydrodynamics simulations. This platform enables detailed investigations into the limits of hydrodynamic scaling in high-energy-density systems.

Comparative mortality risks of antipsychotic medications in community-dwelling older adults.

BACKGROUND: All antipsychotic medications carry warnings of increased mortality for older adults, but little is known about comparative mortality risks between individual agents. AIMS: To estimate the comparative mortality risks of commonly prescribed antipsychotic agents in older people living in the community. METHOD: A retrospective, claims-based cohort study was conducted of people over 65 years old living in the community who had been newly prescribed risperidone, olanzapine, quetiapine, haloperidol, aripiprazole or ziprasidone (n = 136 393). Propensity score-adjusted Cox proportional hazards models assessed the 180-day mortality risk of each antipsychotic compared with risperidone. RESULTS: Risperidone, olanzapine and haloperidol showed a dose-response relation in mortality risk. After controlling for propensity score and dose, mortality risk was found to be increased for haloperidol (hazard ratio (HR) = 1.18, 95% CI 1.06-1.33) and decreased for quetiapine (HR = 0.81, 95% CI 0.73-0.89) and olanzapine (HR = 0.82, 95% CI 0.74-0.90). CONCLUSIONS: Significant variation in mortality risk across commonly prescribed antipsychotics suggests that antipsychotic selection and dosing may affect survival of older people living in the community.

Feasibility and effectiveness of an electronic hand hygiene feedback device targeted to improve rates of hand hygiene.

Various electronic tools have been developed to monitor hand hygiene compliance (HHC). A prospective, investigator-blinded, pilot study was conducted to evaluate the feasibility and effectiveness of an electronic hand hygiene feedback device to improve rates of hand hygiene. The first month of participation provided baseline rates of HHC (37%). During months 2-5, mean HHC rates were 43%, 44%, 45%, and 49% respectively (P < 0.001). Implementing this electronic device was feasible and showed a modest improvement in rates of HHC. Subsequent studies are warranted to validate the impact of such electronic devices on a larger scale.

The effect of intravenous immunoglobulins on the progression of experimental autoimmune myocarditis in the rat.

The aim of this study was to evaluate the efficacy of two experimental regimes of human intravenous immunoglobulins (IVIG) on the progression of experimental autoimmune myocarditis (EAM). EAM is induced by immunization against myosin and represents a T-cell-dependent disorder that progresses toward dilated cardiomyopathy similar to the human equivalent. No effective treatment is currently at hand for management of the disorder, as immunosuppressant drugs are associated with multiple side effects. Three groups of Lewis rats were induced to develop EAM by immunization with porcine myosin and sacrificed 21 days later. Group A received a 5-day regimen of IVIG (800 mg/kg) following induction of the disorder; Group B received a daily dose of IVIG (800 mg/kg) and group C was treated with PBS. IVIG given daily but not during the first 5 days significantly suppressed myocarditis score (0.81 +/- 0.26 and 1.14 +/- 0.42, respectively) in comparison with controls (mean score of 1.78 +/- 0.36). The effect was accompanied by a reduction in the cellular and humoral immune response of the respective animals toward myosin. IVIG was deposited within the extracellular matrix surrounding the damaged myocytes. TNF-alpha expression was reduced in both groups treated with IVIG, whereas iNOS expression paralleled the extent of myocardial inflammation regardless of treatment. IVIG at doses twice those applied for human disease are effective in ameliorating the progression of EAM. The effect may be mediated by suppression of the cellular and humoral response to myosin. IVIG may be found clinically feasible in humans as an adjuvant or single therapy for autoimmune myocarditis.

Impact of geographic proximity to cardiac revascularization services on service utilization.

BACKGROUND: In a highly competitive health care environment, even microgeographic differences in availability of tertiary services might affect access to care. OBJECTIVES: To study the impact of (1) geographic distance from patient's residence to cardiac revascularization services and (2) the availability of cardiac revascularization services at the hospital nearest the patient's residence on utilization of these services in a geographically small, densely populated area. METHODS: Historical cohort study of 55,659 New Jersey residents hospitalized between 1992 and 1996 with primary diagnosis of acute myocardial infarction (AMI). MAIN STUDY OUTCOMES: Use of percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass graft surgery (CABG) within 90 days of initial hospitalization for AMI and in-hospital mortality. Distance from patient's residence to nearest hospital with cardiac revascularization services (PTCA and CABG) was a straight-line distance in miles, categorized as 0 to <2, 2 to <5, 5 to <10, 10 to <15, 15 to <20, 20 to <25, > or =25 miles. Adjusted odds of PTCA or CABG use at each distance category were compared with odds at > or =25 miles. RESULTS: A strong linear decline in adjusted odds ratios for PTCA use was found with increasing distance of this service from the patient's residence (p <0.05). Adjusted odds of PTCA use were 2.4, 2.1, 1.8, 1.5, 1.3, and 1.0 times higher for each increasing distance category in comparison with > or =25 for patients aged <65 and 3.1, 2.7, 2.2, 1.9, 1.7, and 1.1 for patients aged > or =65. Use of CABG was also higher for patients residing closer to cardiac revascularization services. The availability of these services at the hospital nearest to the patient's residence also increased utilization. In-hospital mortality was not associated with distance from services. CONCLUSION: Even across a relatively small geographic area, shorter distance to services and availability of services at the nearest hospital were strongly related to increased utilization of cardiac revascularization services.

Blood pressure variability and urinary electrolyte excretion in normotensive adults.

The principal aim of the present study was to determine the relationship of ambulatory blood pressure (BP) to urinary electrolyte excretion in normotensives. Twenty-five young adults underwent ambulatory BP and heart rate monitoring while collecting urine over 24 h. The correlations of 24 h urine sodium excretion and the ratio of sodium/potassium excretion with systolic BP in the laboratory (r = 0.12 and 0.24), ambulatory awake (r = 0.11 and 0.24), and ambulatory asleep (r = 0.24 and 0.31) settings were all in the positive direction but not significant. However, 24 h sodium excretion did correlate significantly and positively with awake and asleep ambulatory systolic (r = 0.45 and 0.41, P < .05) and diastolic (r = 0.42 and 0.43, P < .05) coefficients of variability. Thus, in normotensives on an unlimited diet, 24 h urinary sodium was more closely related to ambulatory BP variability than to BP level.

The relationship of plasma renin activity to clinic and ambulatory blood pressure in elderly people with isolated systolic hypertension.

Eighty-one untreated elderly patients with clinic-defined isolated systolic hypertension (ISH) and 39 normotensive elderly subjects underwent 24-h ambulatory blood pressure monitoring. Before the ambulatory blood pressure monitoring, EDTA-anticoagulated venous blood was obtained from seated subjects for determination of plasma renin activity. Ambulatory blood pressure and heart rates were determined at 15-30-min intervals by a validated, portable non-invasive technique (Spacelabs 5200). Ambulatory blood pressure variability was defined for each subject as the standard deviation and the coefficient of variation of the ambulatory blood pressure. The mean awake systolic blood pressure was much lower than the clinic-determined value in the ISH group (P less than 0.001), but only slightly so in the normotensive group. Forty-two per cent of the clinic-defined ISH group had mean awake ambulatory systolic blood pressures below the 90th percentile of the normotensive group. A discrepancy between office and ambulatory blood pressures was not associated with blood pressure variability, heart rate or plasma renin activity.

Comparison of office, home and 24-hour ambulatory blood pressures in borderline and mild hypertension.

Clinic/office (casual), home (self), and twenty-four-hour ambulatory (ABP) blood pressure determinations were compared in 32 subjects defined by conventional office criteria as mild or borderline hypertensives. Office diastolic blood pressures (mean 93.1 +/- 5.3 mmHg) were significantly higher than either home (mean 88.9 +/- 7.1 mm Hg) or awake ABP (mean 88.4 +/- 8.4 mm Hg) readings for the total group, as well as for the mild hypertension subgroup (office mean 96.0 +/- 3.5 mm Hg, home mean 91.0 +/- 8.0, awake ABP mean 90.4 +/- 8.8) but not for the borderline subgroup. In the total study group, office diastolic blood pressure (DBP) correlated better with home DBP (r = 0.58, p = 0.0005), than with the awake ABP (r = 0.40, p = 0.02). Home DBP correlated well with awake DBP (r = 0.48, p = 0.006). In subgroup analysis, office DBPs correlated well with home (self) readings for both the mild (r = 0.53, p = 0.03) and the borderline (r = 0.62, p = 0.01) subgroups. When office DBPs were compared with awake ABP DBPs, the correlation coefficient for the mild subgroup was significant (r = 0.49, p = 0.04); this was not the case for the borderline subgroup (r = 0.10, p = NS). Comparison of home (self) DBPs with awake ABP determinations revealed a good correlation for the borderline subgroup (r = 0.63, p = 0.01) but not for the mild subgroup (r = 0.35, p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)