Incoming CMA president will emphasize quality of professional life

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Manpower problems continue to plague Newfoundland

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The Quebec Medical Association calls for regroupement

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Better communication urged for pharmaceutical manufacturers

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Characterization of the hormone-sensitive phosphatidylinositol pool in WRK-1 cells

WRK-1 rat mammary tumor cells respond to vasopressin with an increase in the rate of phosphatidylinositol turnover. Evidence derived from a series of experiments performed under various prelabeling conditions suggests that the hormone-sensitive phosphatidylinositol resides in a distinct pool within the cell, accounting for approximately 17% (8-37%) of the total cellular phosphatidylinositol. The possibility that two distinct cell types might explain this finding is unlikely since neither newly cloned nor thymidine-blocked cells exhibit any alteration in the nature of their response. This hormone-sensitive phosphatidylinositol moiety has the following characteristics. 1) Under equilibrium labeling conditions, it is completely turned over within 5 min of hormone addition. 2) It is both synthesized and degraded even in the absence of hormone, although at a much slower rate. 3) Under the conditions employed, there does not appear to be transfer of phosphatidylinositol from the insensitive to the sensitive pool. A model of these events is outlined.

The isolation of cDNA clones for human apolipoprotein E and the detection of apoE RNA in hepatic and extra-hepatic tissues

We have isolated cDNA clones coding for apolipoprotein E (apoE) from a cDNA library prepared from adult human liver mRNA. Mixtures of 128 different oligonucleotides, 17 residues long were synthesised to be complementary to regions of the mRNA corresponding to amino acids 1-6 and 151-156. Five independent apoE clones were selected by direct screening of 5000 recombinants with the two oligonucleotide mixtures. Two overlapping clones contain the 3'-untranslated sequence, the entire coding sequence and an additional 30 bases 5' to the amino terminus of the mature protein. The DNA sequence has been determined spanning the known sites of amino acid substitutions which account for the observed protein polymorphism of apoE. Using the clones as probes in Northern blot analysis of total human liver and kidney RNAs and leucocyte poly(A)+ RNA we have detected a single species of mRNA in liver and kidney of 1.2 kb and two larger species in leucocyte RNA. The level of expression of the mRNA in kidney is approximately 10% of that in liver while the level of apoE RNA sequences in the leucocytes is less than 1% of that in the liver.