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Biomedical subjects

C Tsopanakis

Publications and source records attributed to C Tsopanakis.

21 records · Page 2Linked to original sources

Bacteriophage MX-1: properties of the phage and its structural proteins.

Bacteriophage MX-1 is a virulent DNA phage for Myxococcus. The host range includes strains of Myxococcus xanthus, M. fulvus and M. virescens. The phage has a sedimentation coefficient (S degrees 20,w) of 1145S and a density of 1-531 g/ml. By using SDS-polyacrylamide gel electrophoresis, 23 phage proteins with apparent mol. wt. between 10000 and 150000 were resolved. Gel filtration in the presence of non-ionic detergent partially resolved the proteins. The fraction excluded from Sephadex G-100, fraction 1, contains two glycoproteins. Fraction 1 was resolved into three fractions (1-1, 1-2 and 1-3) by chromatography on Sephadex G-200. The glycoproteins were present in fraction 1-2; all the proteins from this fraction were derived from the phage tail. Comparison of the amino-acid, hexosamine and neutral-sugar compositions of the two glycoproteins showed that they are distinct molecular species; the smaller molecule is not a subunit of the larger. The significance of these findings is discussed and compared with the proteins of the tails of T-even phage of Escherichia coli.

Amino Acids↗

How harmless is FFA enhancement?

Standard heparin as well as low molecular weight heparin (LMWH) increase lipid levels in serum. It has been reported that a diet rich in long chain saturated fatty acids can enhance the susceptibility to experimental thrombosis. The mechanism by which serum fatty acids may provoke thrombosis is not clear. It is possible that the fatty acids change the properties of the cell membrane and thereby modify the response of platelets to aggregating agents. Heparin and its LMW fractions, by mobilising lipoprotein lipase that hydrolyses serum triglycerides (TG), cause the serum TG to increase, a well known "clearing effect' of heparin in turbid lipemic plasma. This effect may have no significance when it lasts for a short time; however, a long-lasting heparin effect on TG serum levels may have important consequences. The purpose of this study was to examine the time span of the action of heparin and its fractions and to investigate variations in the concentration of digoxin, which is a compound with narrow therapeutic width. The investigated substances after 2 days administration, provoked serum concentration increases of free fatty acids (FFA), TG and HDL-C. Seven days after stopping drug administration, FFA and HDL-C levels remained high, while triglycerides declined. Serum total cholesterol remained unchanged throughout. Digoxin levels increased non-significantly after heparin administration and during swimming stress, while a lipid diet caused a serum digoxin concentration increase.

Animals↗