Effect of different essential amino acid deficiencies on amino acid pools in rats.
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Amino Acids↗
Biomedical subjects
Y Peng
Publications and source records attributed to Y Peng.
Using multiple decrement models to estimate risk and morbidity from specific AIDS illnesses. Multicenter AIDS Cohort Study (MACS).
A simple non-parametric approach is developed to simultaneously estimate net incidence and morbidity time from specific AIDS illnesses in populations at high risk for death from these illnesses and other causes. The disease-death process has four-stages that can be recast as two sandwiching three-state multiple decrement processes. Non-parametric estimation of net incidence and morbidity time with error bounds are achieved from these sandwiching models through modification of methods from Aalen and Greenwood, and bootstrapping. An application to immunosuppressed HIV-1 infected homosexual men reveals that cytomegalovirus disease, Kaposi's sarcoma and Pneumocystis pneumonia are likely to occur and cause significant morbidity time.
AIDS-Related Opportunistic Infections↗
Modeling diagnostic reasoning: a summary of parsimonious covering theory.
Parsimonious covering theory is a formal model of diagnostic reasoning. Diagnostic knowledge is represented in the theory as a network of causal associations, and problem-solving is represented in algorithms that support a hypothesize-and-test inference process. This paper summarizes in informal terms the basic ideas in parsimonious covering theory.
Algorithms↗
Markers of thromboembolization in a bovine ex vivo left ventricular assist device model.
The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricular assist device (LVAD) model in calves. Each of eight calves received a series of three LVADs, each operating for 24 hr. Blood microemboli were measured directly by a laser (624 nm and 828 nm) light scattering microemboli detection (LSMD) system through the LVAD outflow cannula and by constant pressure filtration (CPF) of blood samples from the LVAD outflow cannula. Hematologic parameters were also measured. After LVAD removal, perivalvular thrombi were evaluated using polar coordinate mapping. The average LSMD and CPF results correlated. For example, in one series of three calves, one ventricle exhibited significantly greater thrombogenesis than did the other ventricles, as indicated by both the LSMD and CPF results. In a series of five calves, one calf developed an abnormally high activated thromboplastin time (APTT), even in the absence of heparin. For two of the three ventricles tested in that calf, microemboli concentration (CPF), Factor XII activity, level of fibrin degradation products (FDP), and accumulated thrombus were significantly lower than for the other calves. The whole blood viscosity (WBV, at 230 s-1) in this calf also decreased to lower values than were seen with the other calves.
Animals↗
Eccrine acrospiroma of the eyelid with oncocytic, apocrine and sebaceous differentiation. Further evidence for pluripotentiality of the adnexal epithelia.
A wide variety of sweat gland tumors occur in the eyelids. We used light and electron microscopy to investigate an eccrine acrospiroma showing areas of oncocytic, apocrine and sebaceous differentiation. To our knowledge this is the first report of an oncocytic lesion arising from an eccrine sweat gland, and only the second report of such a lesion arising from the skin. Furthermore, apocrine and sebaceous differentiation are atypical in lesions originating from sweat glands. The wide spectrum of differentiation in this adenoma lends further support to the concept of pluripotentiality of the adnexal glandular epithelia.
Adenoma, Sweat Gland↗
Bioartificial thyroid. The in vitro culture of microencapsulated rabbit thyroid tissue.
A new technique of encapsulating thyroid tissue with an artificial membrane for protection against immune attack is reported. The membrane was made of calcium alginate and a poly-L-lysin coating. The membrane prevents the diffusion of large molecules such as hemoglobin but freely permits the passage of smaller molecules such as T4 and culture medium 1640. Because larger molecules are barred, the contents of the microcapsules are safe from immune system rejection. In vitro cultured, microencapsulated rabbit thyroid tissue secreted T3 and T4, achieving a concentration of 8.68 +/- 2.93 nmol/L and 245.23 +/- 124.87 nmol/L, after 3 days; this level remained steady for 6 to 9 days of incubation. These microcapsules show promise as a treatment modality and as a possible solution to the problem of immuno-isolation.
Animals↗