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Biomedical subjects

G Frenette

Publications and source records attributed to G Frenette.

51 records · Page 3Linked to original sources
PubMed1979

Clinical study of a new antikeloid agent.

An old healing drug has been assessed and found to be of clinical value in stopping the inflammatory phase of hypertrophic scars and keloids. So far, this drug has no known side effects other than occasional mild gastric intolerance and allergic reaction. Our findings are well supported in the literature. The effect of the drug on other forms of connective tissue anomalies that present an inflammatory phase is similar to that on keloids, gradually brining scars to the maturation phase. Our results on this will be published later. Madecassol has also been shown to have a preventive effect on burn and postoperative hypertrophic scars. It compares favorably in effectiveness with compression bandaging, and gives more lasting results than intralesional cortisone or radiation therapy. Finally, Madecassol has a placebo effect of 29%-well within acceptable limits.

Adult↗
PubMed1977

[Diphtheria epidemic occurring on the North Shore of the St. Lawrence River in the fall of 1974].

An outbreak of diphtheria occurred on the North Shore of the St. Lawrence River at the beginning of September 1974. It started with the death of an 18-year-old forest worker Sept. 5, spread over a vast area of the North Shore and lasted until the end of October that year. Eleven strains of toxigenic Corynebacterium diphtheriae intermedium, type K were isolated. Eleven of the 12 patients had characteristic diphtheritic pharyngitis with pseudomembranes. Preventive measures, set forth immediately after the third case was declared, included the following: (a) daily surveillance of all contacts, (b) isolation or preventive hospitalization of persons with all types of pharyngitis, (c) mass vaccination of all susceptible persons and (d) search for healthy carriers of the germ. No strains of toxigenic C. diptheriae were isolated from patients preventively hospitalized or from the 1235 individuals among whom carriers were sought. Among the main characteristics of this epidemic, the mean age of the patients (17 years), their mobility and their habits are factors that could have made it almost uncontrollable. It is also remarkable that this outbreak occurred in such a scattered population of adolescents, in 82% of whom the Schick test was negative.

Adolescent↗
PubMedDate not supplied

Identification of arginine esterase as the major androgen-dependent protein secreted by dog prostate and preliminary molecular characterization in seminal plasma.

This work was undertaken to determine the identity of the major androgen-dependent 15,000 molecular weight protein previously observed on SDS polyacrylamide gel electrophoresis of both dog prostate cytosol and dog seminal plasma. The protein was identified as one of the two chains of arginine esterase on the basis of its ability to bind 3H-diisopropylphosphofluoridate (DFP), an active site titrant of serine proteases. Furthermore, since the other polypeptide chain was heterogeneous, at least five distinct peaks of arginine esterase activity could be separated by chromatofocusing under nonreducing conditions. The molecular weight of the seminal plasma protein was estimated at 29,500 by Sephadex G-100 gel filtration, and at 25,000 by SDS polyacrylamide gel electrophoresis in the absence of mercaptoethanol. In the presence of mercaptoethanol, two major peaks were observed with molecular weights of 15,000 and 14,000. These results show that arginine esterase of dog seminal plasma is a serine protease composed of two different chains linked by disulfide bridges. One of the chains contains the reactive serine group. The other one is probably glycosylated since it presents several isoelectric points.

Animals↗
PubMedDate not supplied

Isolation from human seminal plasma of an abundant 16-kDa protein originating from the prostate, its identification with a 94-residue peptide originally described as beta-inhibin.

In addition to other known markers of the human prostate, it was shown that the prostatic fraction of the split ejaculate was rich in a 16-kDa protein with properties not described previously. This protein was purified from human seminal plasma using ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, and gel filtration on Sephadex G-100. The purified protein showed a single prominent spot on two-dimensional gel electrophoresis. The sequence of the first 40 amino acids that could be positively identified was identical to that of a prostatic secretory protein of 94 amino acids (PSP94) previously designated as beta-inhibin. Antibodies produced in rabbits against the purified protein were used to develop a radioimmunoassay. These antibodies appeared to recognize only the NH2-terminal portion of the native molecule since they did not react with a synthetic peptide composed of the 28 C-terminal residues. The radioimmunoassay showed that the concentration of the protein was 1320 +/- 183 micrograms/ml in the seminal plasma of adult fertile men and 1134 +/- 136 micrograms/ml in vasectomized patients. In hypertrophic and adenocarcinomatous prostates, the concentrations were 326 +/- 156 and 104 +/- 23 micrograms/ml, respectively, while values were lower than 0.060 micrograms/ml in the testis, epididymis, vas deferens and liver. The blood plasma concentration was 0.019 +/- microgram/ml in 23 asymptomatic men 45 to 65 years old and 0.115 +/- 0.036 microgram/ml in eight patients with prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Abundant cysteine-rich protein-1 is localized in the stromal compartment of the human prostate.

The cysteine-rich protein-1 (CRP1) is one of the major proteins of the human prostate. Because of the suspected importance of that protein in cell proliferation and differentiation, its expression was investigated in the prostate, prostatic cancer cells, and other organs of the body. At the mRNA level, the highest concentrations of CRP1 were found in the prostate and the colon followed by the brain and the testis. It was virtually absent from the spleen, liver, heart, and kidney. Prostatic cancer cells PC-3, DU-145, and LNCaP also expressed CRP1 mRNA but virtually no protein. CRP1 protein localization in tissues was determined by immunohistochemical analysis using polyclonal antibodies developed against recombinant CRP1 protein. Strong positive cytoplasmic immunoreactions were observed only in the stromal compartment of the prostate and of other smooth muscle-rich tissues without significant staining in any secretory epithelium. These results, along with previously reported data of colocalization of CRP1 with stress fibers and adhesion plaques, suggest that the main function of CRP1 may be structural.

Carrier Proteins↗
PubMedDate not supplied

High concentrations of the macrophage migration inhibitory factor in human seminal plasma and prostatic tissues.

During purification procedures to isolate kallikrein hK2 from human seminal plasma, kallikrein hK2 was found to be associated with another protein after several chromatographic steps. This study was conducted to identify the hK2 companion protein and characterize its properties and distribution. The protein was identified as macrophage migration inhibitory factor (MIF) by its NH2-terminal amino acid sequence. It had an enzymatic activity identical to that of recombinant MIF. Its concentration varied between 1 and 10 micrograms/mL in various seminal plasma. By immunohistochemical analysis, MIF was found to be localized mainly in the epithelial cells of normal and cancerous prostates. Since MIF is a well-known proinflammatory mediator, these results suggest that it may have important functions in both human reproduction and prostatic physiology.

Amino Acid Sequence↗
PubMedDate not supplied

Leiomyoma-derived growth factors for smooth muscle cells.

The presence of growth substance(s) for smooth muscle cells and fibroblasts was documented in extracts of human leiomyoma tissues (Koutsilieris et al, Am. J. Obst. Gynecol. 163: 1665-1670, 1990). In this study leiomyoma tissues (700 grs) obtained at surgery were extracted and purified using CM-sepharose, heparin-sepharose and reverse-phase high performance liquid chromatography (r-HPLC). The mouse NIH/3T3 cell fibroblasts (ATCC-CRL 1658) and the rat smooth muscle cells A10 (ATCC-CRL 1476) were used as indicator bioassay systems assessing the proliferative effect (tritiated-thymidine incorporation and cell number) of leiomyoma extracts. The profile of peptides purified by cm-sepharose, heparin-sepharose and by r-HPLC was analyzed by standard SDS gel electrophoresis. An overall 50,000 fold purification was achieved of a preferentially acting material on rat aorta smooth muscle cells (A10 cells). This material possessed mitogenic activity equivalent to epidermal growth factor (EGF) on A10 smooth muscle cells, in vitro. We believe that the final chemical definition of such leiomyoma-derived growth substance with preferential action on smooth muscle cells may elucidate the paracrine and/or autocrine interactions among myometrial cells and thus could provide new clues for the pathogenesis of uterine leiomyomas.

3T3 Cells↗
PubMedDate not supplied

In vitro interactions of calmodulin with the ovine proacrosin-acrosin system.

The authors studied the interaction of calmodulin (CaM) with proacrosin and acrosin from ram spermatozoa. CaM binding evaluated by the [125I]-CaM overlay procedure was shown to occur preferentially with both proacrosin and acrosin in the presence of EGTA; in the presence of Ca2+, the interaction was less intense. Further studies with native proenzyme preparations showed that proacrosin activation at pH 7.1 or 8.0 was significantly accelerated in the presence of CaM and EGTA (t1/2 = 23 min vs. 55 min for EGTA alone at pH 7.1), but not in the presence of Ca2+ (t1/2 = 73 min). The enzymatic activity of acrosin towards benzoyl arginine paranitroanilide, however, was not significantly affected by CaM whether Ca2+ was absent or present. Finally, the authors demonstrated that acrosin hydrolyzed CaM rapidly and extensively in the presence of EGTA. These results indicate that CaM interacts in vitro with proacrosin and acrosin, and that acrosin can attenuate CaM activity through proteolysis. Whether these interactions also occur in vivo and are involved in some aspects of spermatozoa function remains to be determined.

Acrosin↗
PubMedDate not supplied

Urokinase-type plasminogen activator: a paracrine factor regulating the bioavailability of IGFs in PA-III cell-induced osteoblastic metastases.

The transplantation of PA-III rat prostate cancer cells onto rat skeleton produces osteoblastic metastases. Therefore w e studied the paracrine interactions between the PA-III cells and osteoblast-derived osteosarcoma cells (UMR 106 cells). A serine protease secreted by PA-III cells hydrolyzed IGF-binding protein-1 and IGF-binding protein-2 (IGFBP-1 and IGFBP-2) detected in the cell culture media (CM) of OMR 106 cells by western ligand blotting. The serine protease of PA-III cell CM was purified using a benzamidine affinity column. This protease was a protein of 45-50 kDa on polyacrylamide gel electrophoresis under non-reducing conditions but generated two protein bands under reducing conditions; a) one of 33-35 kDa possessing protease activity and b) another of 20-25 kDa which was proteinolytically inactive. Sequence analysis identified the amino acid sequence of the a-chain (20-25 kDa band) and of the b-chain (33-35 kDa band) of rat urokinase-type plasminogen activator molecule. Urokinase purified from PA-III cell CM hydrolyzed IGFBPs of UMR 106 cells and stimulated the proliferation of UMR 106 cells in serum-free cultures. Its protease activity was abolished by benzamidine and aprotinin. Its mitogenic activity for osteoblasts was inhibited by anti-IGF-I monoclonal antibody. Northern blot analysis documented the expression of the urokinase-type plasminogen activator gene in the mRNA extracted from PA-III cells. Urokinase expression was inhibited by dexamethasone. Therefore, we conclude that urokinase-type plasminogen activator stimulates osteoblasts via an IGF-I dependent mechanism. Hydrolysis of the IGFBOPs at the sites of PA-III cell-induced bone tumors account for an increased bioavailability of IGFs. This may facilitate the development and the growth of PA-III cell-induced bone tumor and can also mediate the subsequent local osteoblastic reaction.

Animals↗
PubMedDate not supplied

Potential involvement of kallikrein hK2 in the hydrolysis of the human seminal vesicle proteins after ejaculation.

We have recently demonstrated in liquefied human seminal plasma the presence of the novel kallikrein hK2 in association with protein C inhibitor (PCI) as a 75-kDa complex. In the present study, we showed that hK2, immediately after ejaculation, was recovered only in its free form but complex formation with PCI occurred rapidly thereafter and was completed within 10 minutes. That reaction required an enzymatically active kallikrein. In order to determine the patterns of hydrolysis of major seminal vesicle proteins, semenogelins and fibronectin were exposed to hK2 and to hK3 (prostate-specific antigen or PSA) and cleavage sequences were identified by N-terminal sequencing. Free hK2 was able to hydrolyze semenogelins and fibronectin in vitro. Most of cleavage sites were at the carboxyl-side of arginyl residues. Semenogelins were hydrolyzed to a similar extent by catalytic (and similar) concentration of either hK2 or PSA though no common cleavage sites was identified for both proteinases. Unlike semenogelins, fibronectin was hydrolyzed much more efficiently by hK2 than by PSA. These results show that hK2 is enzymatically active during a short period of time after ejaculation, that major seminal vesicle proteins can be the target of this proteolytic activity, and that hK2 and PSA have different substrate specificities.

Antibody Specificity↗