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Biomedical subjects

T M Chang

Publications and source records attributed to T M Chang.

At least 343 records · Page 19Linked to original sources
PubMed1977

Clinical evaluation of the clearance profiles of a portable, compact, dialysate-free system incorporating microencapsulated charcoal hemoperfusion for blood purification with ultrafiltration for fluid removal.

A total of 30 procedures have been carried out in two patients using a new portable, compact, dialysate-free system formed by combining 300 gms of albumin--cellulose nitrate microencapsulated activated charcoal (ACAC) in series with a small Amicon ultrafiltrator. Blood passing through the ACAC hemoperfusion system is purified of waste metabolites and toxins. Fluid removal is carried out with the hydrostatic pressure of the blood passing through the dialysate-free ultrafiltrator. Since ACAC hemoperfusion is much more efficient than hemodialysers for blood purification, the combined system with the ultrafiltrator results in a very efficient system for blood purification and fluid removal. Typical clearance data for the combined systems include: 75 ml/min for 2000--5000 MW; 112.7 ml/min for 300--1500 MW; 235 ml/min for creatinine; 240 ml/min for uric acid; 2500--2700 ml/2 hours for water removal; and 17--18 gm/2 hours for NaCl removal. Guanidines, mercaptans, and PTH are also cleared very efficiently.

Charcoal↗
PubMed1976

Biodegradable semipermeable microcapsules containing enzymes, hormones, vaccines, and other biologicals.

Semipermeable microcapsules were prepared using biodegradable material as the enclosing membranes. For instance, polylactic acid was used as membrane material to microencapsulate biologically active materials. Asparaginase microencapsulated within polylactic acids functions effectively in converting external asparagine into aspartic acid and ammonium. By variations in permeability characteristics, insulin microencapsulated within polylactic acid can be released at pre-adjusted rates. Thus, release rates of 50% in 5 hours, 50% in 20 hours, and 2.5% in 24 hours have been demonstrated. Drugs and vaccines have also been similarily microencapsulated. The advantage of the biodegradable microcapsules is the ability of the body to convert the injected polymer material to normal body metabolites (e.g., CO2 and H2O in the case of polylactic acid) after completion of its function.

Antigens↗
PubMed1975

Epnzymatric recycling of coenzymes by a multi-enzyme system immobilized within semipermeable collodion microcapsules.

Hexokinase (ATP:D-glucose 6-phosphotransferase EC 2.7.1.2) and pyruvate kinase (ATP:pyruvate 2-0-phosphotransferase EC 2.7.1.40) were co-immobilized within semipermeable collodion microcapsules. The resulting microcapsules displayed excellent hexokinase and pyruvate kinase activities, with the measured pyruvate kinase activity considerably greater than that measured for hexokinase. The co-immobilized enzymes, when used sequentially were capable of recycling both ATP and ADP when exposed to the appropriate conditions. Furthermore, when exposed to limiting amounts of coenzyme, the cycles were capable of reusing the total amount of coenzyme supplied at least three times in 90 min. The use of microencapsulation to produce partially "self sufficient" enzyme systems is discussed.

Adenosine Triphosphate↗
PubMed1975

Platelet-surface interaction: effects of dextran 70 on platelet retention in extracorporeal surfaces.

Dextran 70 infusion into dogs prevents platelet adhesion to extracorporeal surfaces as effectively as direct coating of the surfaces with albumin. This is demonstrated by two experimental approaches. One of these involves a detailed analysis in 14 mongrel dogs of the effects of hemoperfusion on the systemic platelet levels, hematocrits, and dextran concentrations. The second approach is in the form of 23 platelet retention tests carried out in four mongrel dogs.

Animals↗