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Biomedical subjects

A Holasek

Publications and source records attributed to A Holasek.

At least 37 records · Page 2Linked to original sources
PubMed1976

Investigation of the abnormal low-density lipoproteins occurring in patients with obstructive jaundice.

The abnormal lipoproteins of the density range 1.019-1.063g/cm3 occurring in the plasma of patients with obstructive jaundice were studied. Subfractionation of this density class by combined sodium phosphotungstate precipitation, ultracentrifugation, and column chromatography on hydroxyapatite and agarose gel yielded essentially three fractions: (1) lipoprotein-X, (2) A triglyceride-rich lipoprotein for which we propose the term lipoprotein-Y and (3) an abnormal lipoprotein, lipoprotein-B. Marked differences between these fractions with respect to electron-microscopic appearance, hydrated densities, chemical composition and immunochemical characteristics were observed. The protein moiety of lipoprotein-X consisted primarily of apolipoprotein-C and albumin. Lipoprotein-Y showed, in addition to apolipoprotein-C, the presence of apolipoprotein-B. The 'lipoprotein-B' fraction isolated from sera of these patients had higher triglyceride and free cholesterol contents than that of normal individuals and an unusually high content of apolipoprotein-C. The relative distribution of lipoprotein-X, lipoprotein-Y and 'lipoprotein-B' varied from patient to patient. The importance of considering the existence of lipoprotein-Y in screening patients for cholestasis by the lipoprotein-X test is discussed.

Cholestasis↗
PubMed1975

[Quantitative determination of aqueous humor proteins by electroimmodiffusion in an antiserum containing agarosegel (author's transl)].

An exact quantitation of aqueous humor proteins within a few hours can be attained by an modification of the quantitative estimation of the proteins by electrophoresis in agarose gel established by Laurell. The aqueous humor proteins form long immunoprecipitations in agargel. The length of the precipitats is proportional to the concentration. By determination of albumin, coeruloplasmin and transferrin the application can be pointed out.

Albumins↗
PubMed1975

Studies on the composition of pig serum lipoproteins. Isolation and characterization of different apoproteins.

1. Different lipoprotein density fractions from pig serum were isolated by phosphotungstate precipitation followed by purification in the preparative ultra-centrifuge. 2. The protein part of very low density lipoproteins was composed of approximately 52 percent lipoprotein B apoprotein and the rest of lipoprotein C II apoprotein and other as yet unidentified peptides. 3. The protein moiety of low density lipoproteins consisted primarily of lipoprotein B apoprotein (over 95 percent); the amino acid compositions of lipoprotein B apoprotein of very low and low density lipoproteins were practically identical. 4. The predominant polypeptide of pig serum high density lipoproteins exhibited an amino acid composition and a molecular weight very similar to human liprotein A I apoprotein. In contrast to human lipoprotein A I apoprotein, the apoprotein from pigs was found to release leucine first followed by alanine, threonine, and lysine upon incubation with carboxypeptidase A. 5. In pig serum the major lipoprotein C apoprotein was found to be a polypeptide similar in amino acid composition to lipoprotein C II apoprotein from human serum. The molecular weight of this polypeptide is approximately 8000. Incubation experiments with carboxypeptidase A indicate serine to be the most likely C-terminal amino acid.

Amino Acid Sequence↗
PubMed1974

Separation of the main lipoprotein density classes from human plasma by rate-zonal ultracentrifugation.

The major lipoprotein density classes (chylomicrons-VLDL, LDL, HDL(2) and HDL(3)) were isolated from human plasma in a two-step ultracentrifugal procedure using the Ti-14 zonal rotor. The isolation of the two major high density lipoprotein subclasses (HDL(2) and HDL(3)) was achieved in a 24-hr run using a nonlinear NaBr gradient in the density range of 1.00-1.40. The lipoproteins with a density < 1.063 found in the rotor's center were isolated in a second run of 140 min duration using a continuous linear NaBr gradient in the density range of 1.00-1.30. The isolated lipoproteins were analyzed for chemical composition and for electrophoretic mobility; purity of isolated fractions was checked by immunochemistry. The lipoproteins exhibited flotation rates, chemical compositions, and molecular weights similar to those found with the common sequential procedures in angle-head rotors. The amount of lipoprotein lipids in the bottom fraction of the zonal rotor was comparable to that of the angle-head rotor. The described method yields the main lipoprotein density classes free from albumin in a very short running time; compared with the rate-zonal techniques already in use, this method allows the quantitative separation of an additional lipoprotein density class (HDL(2)) without increasing the running time. Furthermore, this procedure proved to be suitable for isolation of plasma lipoproteins from subjects with various types and varying degrees of hyperlipoproteinemia.

Adolescent↗