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Biomedical subjects

W Smith

Publications and source records attributed to W Smith.

At least 307 records · Page 17Linked to original sources
PubMed1985

A mathematical model to predict the optimal control mode for a pusher-plate total artificial heart (TAH).

Table I lists the physiological criteria for ranking each control mode (hemodynamic conditions assumed are listed in Figure 4). For each criteria, each mode was given a ranking of 0 to 3, with 3 the best. At the bottom of the table is the total of all criteria grades. The ranking from best to worst mode is in order: IND, LMA/LMS, Low FR/High FR, RMA/RMS. A discussion of Table I follows: FR is a reliable control mode and has been used extensively clinically, including the recent TAH human implants. The advantage of this mode is its simplicity: if the venous return is below pump capacity, then all incoming blood can be pumped out without any sophisticated controller. However, when the flow demand exceeds the pump capacity, HR must be increased. The ideal situation would be to set FR at one HR and %S, and leave these settings over the life of the recipient. However, a high HR like this would result in relatively high atrial pressures and low flow rates with respect to IND (as shown theoretically, in vitro, and in vivo). Although the patient would have a high maximum COR, the daily COR would be low, resulting in a relatively high AVO2 difference. Finally, FR lacks afterload sensitivity. RMA and RMS received the lowest grade of all modes. Because of the L-L shunt, the stroke length of these modes are smallest, and thus the CO curves and FPS are poorer than any other mode.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1984

An automated algorithm for radionuclide angiocardiographic quantitation of circulatory shunting.

Circulatory shunting may be quantitated by analysis of time-activity curves obtained from radionuclide angiocardiography. A new automated algorithm for performing this analysis is proposed. The algorithm uses mathematical deconvolution techniques to increase the temporal separation of the components of this curve and thereby improves the accuracy of the analysis. The stability of the algorithm to random data errors was assessed by experiments on simulated time-activity curves degraded with pseudorandom noise. Excellent performance was obtained on a set of test problems previously used in the literature. The algorithm was used to quantitate left-to-right shunting in patients undergoing radionuclide angiocardiography during cardiac catheterization. A strong correlation (r = 0.96) was found between pulmonary to systemic flow ratios (Qp:Qs) obtained using the algorithm on radionuclide angiocardiographic data and Qp:Qs values obtained by oximetry at cardiac catheterization.

Adolescent↗
PubMed1984

Regulation of expression of class II major histocompatibility antigens on human peripheral blood monocytes and Langerhans cells by interferon.

Although normal peripheral blood monocytes from different individuals are primarily DR+ (L243), they vary in the mean expression of L243 and the percentage of cells with detectable Leu-10 (DC/DS) and L03 (D). All three species of human recombinant IFNs enhance Ia expression on normal peripheral blood monocytes; however, r-IFN-gamma is much more effective in enhancing the expression of these three class II antigens in vitro than r-IFN-beta or r-IFN-alpha A. In addition, r-IFN-gamma has a more profound effect on the expression of Leu-10 (DC/DS), an antigen critical for presentation in autologous MLR, than on L243 (DR). Adherent monocytes cultured for 5 days develop macrophage characteristics and become strongly positive for all three of these class II antigens without further manipulation. Isolated skin Langerhans cells which are thought to be antigen presenting cells in the epidermis are also strongly positive for all three of these Ia antigens and are unaffected by IFN treatment. Therefore, this early interferon effect on cell surface expression may be the result of enhancing the maturation of monocytes to mature antigen presenting cells.

Adult↗
PubMed1984

Computerized data management as an aid to clinical decision making in rehabilitation medicine.

A computerized data-base management system has been developed as a basis for clinical decision making in rehabilitation. The system allows efficient entry, storage, manipulation, and retrieval of patient performance data. With every new entry all previous entries can be displayed. Thus, identification of trends or rapid changes is far easier than perusing data entered into the hospital chart in a conventional way. The system also allows rapid review of all data entries of the entire rehabilitation team by any individual member. Additionally, correlation of variables can be obtained easily. Use of this system facilitates discontinuation of ineffective programs and identification of complications, thereby reducing hospital stay and cost.

Computers↗
PubMed1983

Nasopharyngeal angiofibroma presenting as adult osteomalacia: case report and review of the literature.

Unexplained osteomalacia may be the result of various neoplasma including ENT tumors. The mechanism of this oncogenic osteomalacia is uncertain, but it may result from a tumor-induced alteration in vitamin-D metabolism or from a direct phosphaturic action of a tumor product. Thorough ENT evaluation of patients presenting with unexplained osteomalacia is indicated, as successful tumor excision can lead to cure.

Female↗
PubMed1982

3-phenylazo-4-hydroxyphenylisothiocyanates: reagents for efficient haptenation of immunoglobulin and other carrier molecules.

The synthesis of 2 non-cross-reacting 3-(substituted-phenyl)-azo-4-hydroxyphenylisothiocyanates is described. These compounds are designed as alternatives to the corresponding hydroxybenzimidates for use in hapten-sandwich double labelling of cell surfaces. The new reagents rapidly and controllably haptenate immunoglobulin and other biological carrier molecules. Haptenated immunoglobulins present the appropriate hapten determinant with little concomitant loss of antigen binding activity.

Animals↗