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Biomedical subjects

I Zawicki

Publications and source records attributed to I Zawicki.

11 recordsLinked to original sources
PubMed1989

A novel approach to electrode signal analysis for glucose determination.

The methodology proposed in this presentation consists in considering the stationary Pt-electrode of an electrocatalytic sensor aimed at glucose measurement together with the reference electrode as a "black box" for which a mathematical model is assumed. The model correlates selected features of the output signal to the concentration of glucose and of interfering substances (urea, amino acids) and to their interactions. The model parameters are experimentally identified. During the measurement, the values of previously selected features of sensor output signal are determined; then they serve as the input data for computation of concentrations of glucose and of interfering substances.

Biosensing Techniques↗
PubMed1982

Circulating immune complexes in rheumatoid arthritis. Selective removal by cryogelation with membrane filtration.

We have developed a system of extracorporeal circulation that removes proteins of the molecular weight of the circulating immune complexes of rheumatoid arthritis by cryogelation with hollow-fiber membrane filtration. A 52-year-old woman with a 36-year history of severe, unremitting, high-titer, seropositive rheumatoid arthritis who had failed to respond to anti-inflammatory, antirheumatic, and cytotoxic drugs was chosen for a trial of this system. A rapid and sustained decrease in circulating immune complexes as measured by C1q binding occurred, accompanied by a much slower improvement in clinical factors of disease activity. Rheumatoid factor changed very little and loss of other serum proteins by the procedure was relatively modest. This new procedure was successful in removing circulating immune complexes in a patient with rheumatoid arthritis, and in inducing a remission in one who has not had such in 36 years, while sparing volume and other plasma proteins.

Antigen-Antibody Complex↗
PubMed1981

Axial changes of blood and plasma flow, pressure, and cellular deposition in capillary plasma filters.

The ability to separate plasma on-line from whole blood by membranes has generated interest in applying this process to source plasma collection and to the therapeutic treatment of various disease states. The availability of capillary membrane devices in particular has prompted investigations in these areas. The deposition of blood cellular elements has required the investigation of those parameters related to fluid and mass flux. Analytical solutions relating blood flow rate, filtration rate, and pressure and deposition with respect to axial distance have been obtained. Comparison of these solutions with preliminary experimental results have been made. Results indicate that the deposition parameter versus distance from the inlet is a very sensitive function of capillary membrane properties and operating conditions. Plasma fluxes are also highly dependent on blood, membrane, and filter properties and operating conditions.

Blood↗
PubMed1981

Chronic ambulatory liver support by membrane plasmapheresis with on-line detoxification.

Blood cellular elements and plasma protein losses are minimal for membrane plasmapheresis with on-line sorbent detoxification. Frequent (6/sk), chronic (3 mos), and long-term (8 hr) perfusions are possible for patients studied. It is recommended in deficiency states involving low protein, hypocoagulability or potential hormonal imbalances that aggressive medical management be applied. With regard to system performance, plasma filtration properties improved by the application of the closed plasma circuit and membranes with superior sieving and filtration properties. The effect of plasma solutes on filtration properties has been noted. In PBC patients the influence of total cholesterol concentration is particularly striking. Significant reduction of FFA and improvement of PMR were achieved in combination with bilirubin removal in liver failure patients, while bile acids (cholyglycine) levels were significantly reduced in 3 of PBC patients who expressed a subjective improvement of about 90% following 3 consecutive treatments. Four of 5 liver failure patients showed improved mental status with one patient surviving.

Adult↗
PubMed1978

Bioengineering aspects of the artificial pancreas.

In this paper, results of work aimed at the development of artificial beta-cells are presented. An electrolytically driven pump is considered to be a proper device for insulin injection. The transient characteristics of the simplified version of such a pump make it suitable for application in open-loop devices. Methods for electrical control of the injection rate of this pump for application in closed-loop artificial beta-cells are given. An essential component of a closed-loop artificial beta-cell is a glucose sensor. A modified version of the glucose sensor has been developed and its performance is described. Considerations of some control problems related to the artificial pancreas are briefly discussed.

Animals↗