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Biomedical subjects

T M Chang

Publications and source records attributed to T M Chang.

At least 307 records · Page 17Linked to original sources
PubMed1980

Tyrosinase immobilized within artificial cells for detoxification in liver failure: I. preparation and in vitro studies.

The in vitro removal of tyrosine by means of perfusion over immobilized tyrosinase within artificial cells was studied. The assayed activity of the microencapsulated tyrosinase was about half the value of the same amount of enzyme in free solution. Further studies were conducted to determine the stability, kinetics, and clearance of this system. The results obtained suggest that immobilized tyrosinase within artificial cells is efficient in removing tyrosine in vitro and further study in an animal model is feasible.

Artificial Organs↗
PubMed1980

Effects of pH and urea concentration on urea removal from dialysate by enzymatic conversion and gas absorption using a capillary hemodialyzer.

This paper reports the effects of initial urea concentrations and pH values on the performance of a capillary hemodialyzer for the removal of free ammonia (NH3) formed by enzymatic hydrolysis of urea. Air was chosen as the gas phase. NaOH was used for alkalinization of dialysate. It was shown that one of the most important parameters was free ammonia concentration. The degrees of alkalinization and the initial urea concentration, were also important. Although even without the addition of NaOH, about 42% of the initial urea can be removed in one hour.

Absorption↗
PubMed1980

Albumin-collodion activated charcoal hemoperfusion in the treatment of severe theophylline intoxication in a 3-year-old patient.

During treatment for asthma, a 3-year-old, 15-kg child was given 750 mg of theophylline in error. Within three hours she was treated with albumin-collodion activated charcoal (ACAC) hemoperfusion. Immediately before treatment her serum theophylline level was 74 microgram/ml. At the end of three hours of hemoperfusion, her theophylline level had fallen to 14.4 microgram/ml and four hours later it was 8.8 microgram/ml. The ACAC hemoperfusion system completely removed all the theophylline passing through it without saturation, and the total amount of drug removed was 500.8 mg (more than two thirds of the dose administered). The technique described is an efficient and rapidly effective method for the treatment of potentially lethal theophylline intoxication. For maximum effectiveness, it must be instituted as soon after intoxication as possible.

Charcoal↗
PubMed1980

A new combined enzyme-charcoal system adsorption on charcoal followed by polymer coating.

A method is described for a new combined enzyme-charcoal system. A model enzyme, urease, was adsorbed on activated charcoal granules which was then coated with ultrathin cellulose nitrate. The assayed activity of this immobilized enzyme was 28.1% /+- 3.12% (mean /+- S.D.) of the activity of urease in solution. The enzyme did not leak out after immobilization and worked efficiently. The assayed urease activity increased with greater amounts of urease/gm immobilized enzyme, but reached a plateau after 40 sumner units/gm. Immobilized urease has good storage and operational stabilities at refrigerator, room and body temperatures. In-vivo studies show that about 90% conversion urea in one single pass is possible.

Adsorption↗
PubMed1979

Long-term clinical assessment of combined ACAC hemoperfusion-ultrafiltration in uremia.

ACAC hemoperfusion was used in series with a small fluid removal system for a clinical trial in the treatment of uremia. A 22-month trial included a pretest control period, test period and a post-test control period. The most significant observations from this trial are: 1) the predialysis body weight of the patient could be maintained closer to the patient's dry weight; 2) there was a significant increase in hematocrit; and 3) there was insufficient removal of urea. With the development of an effective urea removal system, a more compact artificial kidney than any presently available will become feasible.

Blood Chemical Analysis↗
PubMed1979

Effects of glucose dehydrogenase in converting urea and ammonia into amino acid using artificial cells.

A microencapsulated multienzyme system containing urease, glutamate dehydrogenase and glucose dehydrogenase has been used to convert urea and ammonia into an amino acid. The effect of two different glucose dehydrogenases was studied in detail. High-specific-activity glucose dehydrogenase requires minimal cofactor and glucose and can greatly facilitate the further development of this approach for possible clinical applications.

Ammonia↗
PubMed1979

Biochemical, hematological and histological changes in a fulminant hepatic failure rat model for artificial liver assessment.

Galactosamine-induced fulminant hepatic failure rats have been used as a model for statistical assessment of liver support systems. The present study reports in detail the biochemical, hematological and histological changes in these animals. They have been used to study statistically the effects of ACAC charcoal hemoperfusion, cross-circulation and liver perfusion on long-term survival in fulminant hepatic failure.

Animals↗