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C Jolicoeur

Publications and source records attributed to C Jolicoeur.

30 records · Page 2Linked to original sources
PubMed1989

[Prolactin receptor: characterization by monoclonal antibodies and cloning of complementary DNA].

Rat liver prolactin receptor has been partially characterized and purified to homogeneity using monoclonal antibodies. Pure receptor was digested with trypsin and amino acid sequence of receptor fragments determined. This allowed us to clone the prolactin receptor cDNA. Our approach to clone the receptor cDNA consisted of synthesizing oligonucleotides corresponding to the amino acid sequence of receptor fragments, and to screen a cDNA library. Sequencing reveals that prolactin receptor is a 291 amino acid protein, containing an extracellular domain of 210 residues, a single transmembrane segment of 24 amino acids and a cytoplasmic domain of 57 amino acids. Introduction of the prolactin receptor cDNA into various cell types demonstrates that the single protein is sufficient to bind prolactin with the same affinity and specificity reported for the prolactin receptor.

Animals↗
PubMed1988

Cloning and expression of the rat prolactin receptor, a member of the growth hormone/prolactin receptor gene family.

The primary structure of the rat liver prolactin receptor has been deduced from a single complementary DNA clone. The sequence begins with a putative 19 amino acid signal peptide followed by the 291 amino acid receptor that includes a single 24 amino acid transmembrane segment. In spite of the fact that the prolactin receptor has a much shorter cytoplasmic region than the growth hormone receptor, there is strong localized sequence identity between these two receptors in both the extracellular and cytoplasmic domains, suggesting that the two receptors originated from a common ancestor.

Amino Acid Sequence↗
PubMed1987

Lipid analysis of a novel type of cell secretion in the exocrine pancreas: the pancreasomes.

A novel type of cell secretion termed 'microvesicular secretion' has been described recently in the exocrine pancreas. According to this process, microvesicles are released by acinocytes in the pancreas acinar lumen. These microvesicles, identified as 'pancreasomes', were characterized by the presence of a major glycoprotein component originating in the exocrine acinar cell. In the present work, phospholipids of pancreasomes have been identified. Five classes of phospholipid were found: phosphatidylcholines, phosphatidylethanolamines, lysophosphatidylcholines, sphingomyelins and another minor class of ninhydrin-positive phospholipid (phosphatidylserines or lysophosphatidylethanolamines). The ratios of neutral lipids to phospholipids were particularly high (3:1), as estimated by GLC of their fatty acid content. Analysis of fatty acid composition of pancreasomes lipids revealed a very high proportion of two saturated fatty acids, palmitic (40%) and stearic (24%), whereas two main unsaturated fatty acids, oleic (17%) and linoleic (8%), were found in smaller proportions. Differential scanning calorimeter studies on washed pancreasomes indicated that there was no lipid phase transition in their membrane, despite the absence of cholesterol. Our observations show that pancreasomes have an unusual lipid composition and confirm our previous conclusion based on protein analysis that the release of pancreasomes occurs according to an hitherto undescribed type of secretion, in which a glycoprotein is released associated with specific domains of the luminal plasma membrane.

Animals↗
PubMed1987

Changes in the messenger RNA population from the heart of cardiomyopathic hamsters.

Messenger RNAs were extracted from the heart of cardiomyopathic hamsters at different phases of the disease and from age-matched control hamsters. They were translated into proteins in a rabbit reticulocyte lysate in the presence of [35S]methionine, the translational products were fractionated by two-dimensional polyacrylamide gel electrophoresis and analyzed by fluorography. No difference between cardiomyopathic and control hamsters could be detected when comparing the spots corresponding to the major contractile proteins. However, we observed that three translational products of minor abundance were reproducibly decreased in cardiomyopathic hamsters at 60 days (necrotic phase) and 200 days (final phase) but not at 30 days (prenecrotic phase). At 120 days (hypertrophic phase), the decrease could also be detected but was much less pronounced.

Animals↗
PubMed1987

Flow microcalorimetry investigation of the influence of surfactants on a heterogeneous aerobic culture.

The influence of various surfactants on the biological activity of a mixed aerobic culture has been investigated by using flow microcalorimetry. The response of the culture to the addition of homologous n-alkylcarboxylates (C2 to C16) and n-alkylpyridinium bromides (C11 to C14) has been examined under endogenous and substrate saturation conditions, and inhibitory concentrations (MIC or the concentration which decreased the initial activity (heat flux) of the culture by 50%) were determined for each state. Under both conditions, the n-alkylpyridinium bromides were found to be more toxic than the n-alkylcarboxylates of identical chain length, thus confirming that the head group of the amphiphiles plays an important role in the microbial toxicity of surfactants. The relationship observed between the concentration at which 50% of the activity is lost and the chain length of the surfactant further confirms that cellular toxicity is also dependent on surfactant hydrophobicity. In relation to the biodegradability of surfactants in mixed aerobic cultures, the low concentration effects of n-alkylcarboxylates on endogenous culture were investigated in some detail. There appear to be compounded indications that these surfactants are rapidly metabolized by the microorganisms of the mixed culture, at least for homologs lower than C10.

Bacteria, Aerobic↗
PubMed1983

The 60S ribosomal subunit is altered in the skeletal muscle of dystrophic hamsters.

Polysomes from the skeletal muscle of normal and dystrophic hamsters were dissociated into ribosomal subunits by treatment with puromycin and the subunits from both strains were reassociated in all possible combinations. When their protein synthesis activity was assayed in a poly(U)-directed cell-free system at a low magnesium concentration, the reassociated ribosomes from dystrophic hamsters were less active than the ribosomes from control animals. The ribosomal defect is a property of the 60S subunit and is due to a ribosomal component rather than to abnormal binding of a non-ribosomal protein.

Animals↗
PubMed1983

A ribosomal defect in dystrophic hamsters.

Polysomes were isolated from the skeletal muscle, the heart, and the liver of dystrophic and normal hamsters and their protein synthesis activity was assessed in a cell-free wheat germ extract as a source factors and tRNAs. Our results show that there is a shift of the optimal magnesium concentration required for protein synthesis with polysomes from the skeletal muscle and the heart of dystrophic hamsters, as compared with control hamsters. As a consequence of this shift, polysomes from the skeletal muscle and the heart of dystrophic hamsters, were less active than normal ones at low magnesium concentrations, but more active at high magnesium concentrations. These changes in activity were age dependent since, with skeletal muscle, they were observed at 30 days and disappeared at 60 days but reappeared at 120 and 200 days. With heart polysomes, on the other hand, the changes in activity were observed at 60 days but not in younger or older animals. No change in activity was observed with liver polysomes. Similar results were obtained when endogenous mRNAs were replaced by an exogenous messenger such as poly(U). This suggests that the differences in protein synthesis activity between polysomes from dystrophic and normal hamsters are not due to changes in the endogenous mRNAs but result from a ribosomal abnormality.

Animals↗
PubMed1983

Endometrial hyperplasia and neoplasia. Cytologic screening with the Endopap endometrial sampler.

A new endometrial sampling device, the Endopap, was tested in a series of 851 patients. This sampler is of simple design, without moving parts, inexpensive and easy to use. Cellular samples proved adequate in 90% of the cases, usually with very abundant material. Endometrial cancer shed atypical cells in all 20 cases studied. However, only about half the patients with adenomatous hyperplasia were correctly identified by the endometrial sample. This fact seems to reflect the lack of adequate morphologic criteria for the recognition of endometrial hyperplasia; this situation prevails with all types of endometrial cell samplers.

Adenocarcinoma↗
PubMedDate not supplied

Criteria for the cytologic assessment of hyperplasias in endometrial samples obtained by the Endopap Endometrial Sampler.

The Endopap Endometrial Sampler was used in 1,465 women, either just before endometrial biopsy or curettage (in 760 symptomatic patients) or as an office procedure (in 705 women). The samples were inadequate for interpretation in only 8.7% of the cases. Although all malignant lesions were identified by this screening technique, about one-fourth were initially classified cytologically as hyperplasia. Endometrial hyperplasias presented the greatest difficulties in interpretation, with only slightly over half of the proven cases correctly assessed on the endometrial sample. In an attempt to improve the accuracy of the cytologic diagnosis of hyperplasias, ten morphologic features were examined retrospectively in 207 cases. Five of the criteria were shown to provide an increased probability of correctly diagnosing endometrial hyperplasias on the cytologic sample: (1) the overlapping of cells in the glandular clusters or sheets, (2) the presence of nucleoli, (3) anisokaryosis, (4) granularity of chromatin and (5) the presence of sheets of stromal cells. The more of these criteria observed in a given case, the better was the chance of cytologically identifying a hyperplasia in the Endopap sample.

Cell Nucleolus↗