Kinetic and topographical studies of the phosphatidylcholine: ceramide choline phosphotransferase in plasma membrane particles from mouse ascites cells.

The content of endogenous phospholipids in plasma membrane preparations from Ehrlich ascites cells was depleted by exposure to phospholipase C. The enzyme catalyzing the phosphatidylcholine: ceramide choline phosphotransferase reaction was inactivated by this treatment. However, the activity could be restored with exogenous phosphatidylcholines, demonstrating the dependence of the reaction upon the presence of this substrate.

The phosphorylcholine acceptor in the phosphatidylcholine:ceramide cholinephosphotransferase reaction. Is the enzyme a transferase or a hydrolase?

The cholinephosphotransferase reaction is shown to be catalyzed by an enzyme which has no hydrolytic activity and which is different from a phospholipase C type activity also present in these plasma membrane preparations. Diacylglycerols and sphingosine, at a concentration above 0.4 mM, are effective inhibitors of sphingomyelin formation in the presence of 0.

[Surgical interventions on the gallbladder and the biliary tract in the aged].

The surgery of the gall bladder by gallstones, bile duct and alterations of the duodenal papilla are conducted with an increase of lethality. This increased lethality is caused by accompanying ill effects, especially chronical pancreatitis, cholangitis, disturbances of the liver. The indications to operate old patients are occlusions of duodenal papilla relapsing colics with or less occlusing icterus, emphysema of gall bladder or perforation.

The role of endogenous phosphatidylcholine and ceramide in the biosynthesis of sphingomyelin in mouse fibroblasts.

The intracellular location of sphingomyelin formation via the cholinephosphotransferase reaction from both endogenous an exogenous phosphatidylcholine and ceramide substrates has been studied in the subcellular membrane fractions prepared from mouse fibroblasts. The enzyme was found to be located in both the plasma membrane and the Golgi fractions. Activity in the Golgi fraction was stimulated to a greater extent by the addition of exogenous ceramide than was the activity in the plasma membrane fraction.

The formation of sphingomyelin from phosphatidylcholine in plasma membrane preparations from mouse fibroblasts.

The enzymatic formation of radioactive sphingomyelin from [14C]choline-labeled phosphatidylcholine was demonstrated to reside exclusively in the plasma membrane fraction of mouse fibroblasts. This activity has several properties in common with the phosphatidylcholine ceramide phosphocholine transferase of mouse liver microsomes. The enzyme has little if any phospholipase C activity and isotope dilution experiments suggest that phosphatidylcholine is the substrate rather than it is converted to CDP choline, phosphocholine, free choline or glycerophosphocholine prior to the transfer reaction.

A biosynthetic method for the preparation of high specific activity 32P-labeled phospholipids.

32P-Labeled phospholipids with specific activities up to 400 mCi/mmole as well as [32P]CDP-choline were prepared by cultivation of mouse fibroblasts or mouse Ehrlich ascites cells in the presence of [32P]orthophosphate. The method was also used to prepare [methyl-3H]choline-labeled glycerophospholipids from [3H]choline. The yields and the specific activities of the phospholipids were significantly lower when preparations of ox white blood cells were used.

[Spontaneous peripheral proteolysis/2nd communication: Effect of peripheral proteolysis (author's transl)].

With the modified Astrup-plate method a spontaneous peripheral proteolysis was often found in chronical infections of the skin and mucous membranes. The origin of this proteolysis and its effects on the bacterial growth and wound healing were discussed.

[Spontaneous Peripheral Proteolysis/1st Communication: method and results of clinical examinations (author's transl)].

With a modificated Astrup-fibrin plate-method also an inhibition of proteolysis can be registrated. In various medical areas a spontaneous peripheral proteolysis had been found, especially so in chronical bacterial infections.

[Spontaneous peripheral proteolysis as a disturbing factor (author's transl)].

With a modification of the Astrup - fibrin - plate method about 300 patients were investigated. In chronic infections of the skin and mucous membranes a spontaneous peripheral proteolysis was found. There is a connection between infections, proteolysis and chronic continuance.