Publications by authors named "Stanley J Kleis"

Background: Previous studies demonstrated that digital thermal monitoring (DTM) of vascular reactivity, a new test for vascular function assessment, is well correlated with Framingham Risk Score, coronary calcium score and CT angiography. This study evaluates the variability and reproducibility of DTM measurements. We hypothesized that DTM is reproducible, and its variability falls within the accepted range of clinical diagnostic tests.

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Both structural and functional evaluations of the endothelium exist in order to diagnose cardiovascular disease (CVD) in its asymptomatic stages. Vascular reactivity, a functional evaluation of the endothelium in response to factors such as occlusion, cold, and stress, in addition to plasma markers, is the most widely accepted test and has been found to be a better predictor of the health of the endothelium than structural assessment tools such as coronary calcium scores or carotid intima-media thickness. Among the vascular reactivity assessment techniques available, digital thermal monitoring (DTM) is a noninvasive technique that measures the recovery of fingertip temperature after 2-5 min of brachial occlusion.

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Little is known about flow patterns in ventricles supported by continuous flow left ventricular assist devices (LVADs), and valuable information can be obtained with simple flow visualization experiments. We describe the application of several experimental techniques for the in vitro study of ventricular flow patterns (e.g.

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The present study introduces a new experimental model of hypoxia/reperfusion injury using a newly developed bioreactor system. The injury is introduced and kept localized via fluid dynamic manipulation. Using low Reynolds number fluid flow, regions of the culture can be injured while maintaining physiological conditions in the remaining culture.

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A mathematical model is used to investigate the transport of dissolved oxygen from the bulk fluid to the surface of aggregates of animal cells cultured in a rotating bioreactor. These aggregates move through different regions of the bioreactor with a local flow field and concentration distribution that vary with time. The time variation of the Sherwood number and the surface concentration for a range of parameters typical of a cell science experiment executed in the Rotating Wall Perfused Vessel (RWPV) bioreactor in space are investigated.

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Mass transport and mixing of perfused scalar quantities in the NASA Rotating Wall Perfused Vessel bioreactor are studied using numerical models of the flow field and scalar concentration field. Operating conditions typical of both microgravity and ground-based cell cultures are studied to determine the expected vessel performance for both flight and ground-based control experiments. Results are presented for the transport of oxygen with cell densities and consumption rates typical of colon cancer cells cultured in the RWPV.

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