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J C Dreyfus

Publications and source records attributed to J C Dreyfus.

152 records · Page 9Linked to original sources
PubMedDate not supplied

Modifications of phosphoproteins and protein kinases occurring with in vitro aging of cultured human cells.

We have studied the age-related modifications of endogenous phosphorylations and protein kinases in seven different strains of cultured human cells (two fibroblastic and five human liver-derived strains). Endogenous phosphorylation of phosphopeptides by cells incubated in the presence of [32P]orthophosphate constantly changed with aging; these modifications could not be explained only by loss of replicative capacity of these cells. Total casein and phosvitin kinase activity did not change in the course of in vitro cell aging. Gel filtration chromatography and autophosphorylation of partially purified kinase preparations, however, seemed to indicate some age-related modifications of protein kinases. Electrophoresis of active enzymes demonstrated that some histone/protamine kinases decreased with aging while a new 3':5'-cyclic AMP-independent histone kinase band appeared progressively. It is proposed that new protein kinase isozymes could correspond to new genes progressively activated during cell aging and could be closely related to cell senescence and death.

Cell Survival↗
PubMedDate not supplied

[Enzyme diagnostics in lysosomal diseases with emphasis on sphingolipidoses].

The authors describe the conditions and results of the enzymatic diagnosis in various sphingolipidoses, based on their personal experience. A precise diagnosis can be presently made on white blood cells, cultured fibroblasts or amniotic cells, and in some cases on serum or urine. In most cases the use of artificial substrates allows a relatively simple diagnosis. The methods are quantitative or qualitative (especially cellulose acetate electrophoresis, of which a few pictures are shown). The results are particularly clear in Tay-Sachs disease and its variants. Despite the fatal prognosis of most sphingolipidoses it is important to ensure a precise and precocious diagnosis. This is of prime value when a prenatal detection of the disease is considered in case of a future pregnancy.

Amniotic Fluid↗