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Biomedical subjects

G D Antwiler

Publications and source records attributed to G D Antwiler.

4 recordsLinked to original sources

Reduction of low-density lipoproteins with dextran sulfate in patients with familial hypercholesterolemia.

A novel on-line system for the selective precipitation of low-density lipoprotein (LDL) using dextran sulfate has been devised and tested in four patients with heterozygous familial hypercholesterolemia (type II). The mean pretreatment serum cholesterol was 410 mg/dl. Plasma was generated by membrane filtration and LDL and VLDL (very-low-density lipoprotein) were completely precipitated with 10-35 mg% dextran sulfate (Mr 5,000) in the presence of 55 mM Ca2+. The precipitate was removed by filtration and the excess Ca2+ by dialysis. For 41 procedures the mean reduction of plasma solutes was LDL + VLDL 65%, HDL 23%, fibrinogen 19%, albumin 15%, IgG 20%, IgA 19%, IgM 24%. We conclude that dextran sulfate precipitation is an effective method for selective on-line removal of LDL from plasma.

Adult↗

Treatment of hypercholesterolemia by precipitation of lipoproteins with dextran sulfate.

An on-line continuous system for the selective precipitation of low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL) has been devised and tested. This system conserves high-density lipoproteins (HDL) and other plasma macromolecules. LDL and VLDL are precipitated from plasma using 10-35 mg/dl dextran sulfate (Mr 5,000) in the presence of 55 mM calcium with a reduced concentration of monovalent cations. The plasma is obtained by membrane filtration of whole blood using the COBE Centry TPE System (Cobe Laboratories Inc, Lakewood, Co.). The precipitated LDL plus VLDL is removed by filtration, and the electrolytes are restored by dialysis. The plasma minus LDL plus VLDL is then returned to the patient. Four patients with heterozygous familial hypercholesterolemia (type II) were treated 70 times. The mean pretreatment serum cholesterol was 383 mg/dl. The mean reductions in plasma components were: LDL plus VLDL 63%; HDL 27%; fibrinogen 19%; albumin 15%; IgG 20%; IgA 19%; IgM 25%; C3 30%; and C4 27%. The cholesterol returned to near normal values in approximately 2 weeks after each treatment. Four normal volunteers were each treated one time. These individuals had a mean pretreatment serum cholesterol of 201 mg/dl. The mean reduction in plasma components were: LDL plus VLDL 70%; HDL 27%; fibrinogen 24%; albumin 14%; IgG 18%; IgA 17%; IgM 20%; C3 27%; C4 22%; C3 proactivator 12%; alpha 1-antitrypsin 17%; ceruloplasma 17%; transferrin 18%; alpha 2-macroglobulin 17%; and orosomucoid 13%. It is our conclusion that dextran sulfate precipitation is an effective on-line means of selectively removing LDL plus VLDL from plasma while conserving HDL and other plasma macromolecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗

Measurement of the transmittance coefficient spectrum of Cuprophan and RP69 membranes: applications to middle molecule removal via ultrafiltration.

The transmittance coefficients of Cuprophan PT-150 and Rhone-Poulenc AN69 have been defined over a broad MW range. The results can be completely characterized by a simple Gaussian distribution employing 2 parameters, the selectivity and the mean molecular diameter. The selectivities of the membranes studies are identical. The mean MW at 50% cutoff for Cuprophan and RP69 are 2,500 and 11,500, respectively. A membrane model illustrating a semi-empirical correlation between permeability and transmittance has been developed.

Kidneys, Artificial↗