Efficacy of atovaquone-proguanil?
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Antimalarials↗
Biomedical subjects
K Geary
Publications and source records attributed to K Geary.
Wave-front measurement errors from restricted concentric subdomains.
In interferometry and optical testing, system wave-front measurements that are analyzed on a restricted subdomain of the full pupil can include predictable systematic errors. In nearly all cases, the measured rms wave-front error and the magnitudes of the individual aberration polynomial coefficients underestimate the wave-front error magnitudes present in the full-pupil domain. We present an analytic method to determine the relationships between the coefficients of aberration polynomials defined on the full-pupil domain and those defined on a restricted concentric subdomain. In this way, systematic wave-front measurement errors introduced by subregion selection are investigated. Using vector and matrix representations for the wave-front aberration coefficients, we generalize the method to the study of arbitrary input wave fronts and subdomain sizes. While wave-front measurements on a restricted subdomain are insufficient for predicting the wave front of the full-pupil domain, studying the relationship between known full-pupil wave fronts and subdomain wave fronts allows us to set subdomain size limits for arbitrary measurement fidelity.
Journal Article↗
Comparison of streptokinase, urokinase, and recombinant tissue plasminogen activator in an in vitro model of venous thrombolysis.
PURPOSE: Presumed differences in the thrombolytic activity and fibrinolytic specificity of the three commonly used thrombolytic agents, streptokinase, urokinase, and recombinant tissue plasminogen activator (rt-PA), are based on clinical study results, where variability renders meaningful comparisons difficult. An in vitro model of catheter-directed venous thrombolysis was used to compare the three agents. METHODS: Retracted iodine 125-radiolabeled clots that simulate those observed in the venous system were infused with thrombolytic agents at doses analogous to those used clinically. Perfusion with heparinized, whole human blood was undertaken for 60 minutes, measuring the efficacy of thrombolysis through serial quantification of radio tracer released into the circuit. Fibrinolytic specificity was determined by following decrements in perfusate fibrinogen concentration. RESULTS: Streptokinase was the agent associated with the slowest rate of clot lysis (p = 0.01 vs urokinase and rt-PA). Urokinase was associated with an intermediate rate of lysis but appeared to be the agent with the greatest degree of fibrinolytic specificity (p = 0.02 vs streptokinase, p = 0.05 vs rt-PA). Although rt-PA was associated with improved efficacy early in the perfusions, the differences between rt-PA and urokinase dissipated after 30 minutes. CONCLUSIONS: These laboratory observations suggest that urokinase may be the most appropriate agent for catheter-directed venous thrombolysis, offering an advantageous compromise between fibrinolytic specificity and thrombolytic speed.
Analysis of Variance↗
Factors determining survival after ruptured aortic aneurysm: the hospital, the surgeon, and the patient.
The 10-year experience of a single community was reviewed and a multivariate analysis was performed to determine the relative importance of clinical and environmental factors in mortality after ruptured abdominal aortic aneurysm resection. Ruptured aneurysms were repaired in 243 patients in six area hospitals (one university, five community) by 25 surgeons (16 vascular, 9 general). Overall, 30-day mortality was 55% (133/243). Although the mortality by hospital ranged from 44% to 68%, these differences were not statistically significant. However, significant variations occurred in the mortality rates of individual surgeons, ranging from 44% to 73%. The mortality rate for the vascular surgeons was less than that of the general surgeons, 51% versus 69% (p less than 0.05). Clinical factors were evaluated, and the most significant parameters were systolic blood pressure, presence of chronic obstructive lung disease, and history of chronic renal insufficiency. These results support the implication that the degree of specialization of the surgeon and the preexisting health of the patient are the most important determinants of survival after ruptured abdominal aortic aneurysm. The size and sophistication of the hospital appear to be less influential factors.
Aged↗
Isolation of renin-rich rat kidney cells.
Enzymatic dispersion and density gradient (Percoll) sedimentation were used to isolate a population of renin-containing, granule-laden cells (density 1.067 g/ml) from rat kidney cortex. Using immunohistochemistry (light microscopy) and electron microscopy, we defined the presence and ability of these cells to store renin protein(s). A 1000 base pair rat renin complementary DNA was used to show that these cells express the renin gene. The reverse hemolytic plaque assay defined the functional properties of the renin-containing cell. The data are consistent with the postulated inverse relationship between calcium concentration and release of renin. Thus, we have isolated a population of functional rat kidney cells that synthesize, store, and release renin.
Animals↗