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G Carpentier

Publications and source records attributed to G Carpentier.

13 recordsLinked to original sources
PubMed2006

Identification of type-specific and cross-reactive neutralizing conformational epitopes on the major capsid protein of human papillomavirus type 31.

The majority of the neutralizing epitopes of papillomaviruses (PV) are conformation-specific and have not been fully characterised. Studies have, to date, been limited to a few HPV types only. We analysed the epitopes on the major capsid protein (L1) of Human papillomavirus (HPV) type 31 using monoclonal antibodies (MAbs) generated against HPV-31 virus-like particles (VLPs). The type-specific MAbs against HPV-31 were all found to be neutralizing and recognized conformation-dependent epitopes. Two other MAbs directed against a conformational epitope were found to be cross-reactive with other HPV types, and one of them was found to be cross-neutralizing. Cross-reactive antibodies were further investigated using wild-type HPV-16 L1 VLPs and two mutants. The results obtained suggested the existence of a cross-neutralizing conformational epitope at the N-terminal part of the FG loop of the major capsid protein, and the other four cross-reactive MAbs recognized epitopes also located at the N-terminal part of the FG loop.

Amino Acid Sequence↗
PubMed2003

Effect of RG1192, a substituted dextran, on inflammatory response.

RG1192 is one of a series of substituted dextran heparin-like polymers that were shown to accelerate tissue repair in various experimental models. Many efforts have been made to investigate the mechanisms by which these compounds act In these experiments, we studied the effect of RG1192 on inflammatory cells. We showed that intraperitoneal RG1192 injection caused a 5-fold increase in peritoneal polymorphonuclear (PMN) cell number at 6 hr, 8-fold increase at 12 hr and 3-fold increase at 24 hr, as compared to controls. Although the circulating white blood cell count did not show any changes, the number of circulating PMN showed a small early increase. Further investigation had been done on the chemotactic effect of RG1192 on PMN in vitro. The results showed that RG1192 alone increased PMN migration at 0.5 mg/ml and 1 mg/ml, without potentiation by additional IL-8.

Animals↗
PubMed2001

Beneficial use of fibroblast growth factor 2 and RGTA, a new family of heparan mimics, for endothelialization of PET prostheses.

We have studied the endothelialization of polyethylene terephtalate (PET) prostheses coated with collagen by adult human saphenous endothelial cells (EC) under various in vitro conditions. Collagenous PET was impregnated either by Fibroblast Growth Factor 2 (FGF2), heparin, a synthetic heparan sulfate mimic named RGTA 11 (for ReGeneraTing Agent), or combinations of these products. RGTA 11 belongs to a new family of drugs, which have been previously described as stabilizer and protector of heparin binding growth factors (HBGF), and to act in vivo as to stimulate wounded tissue repair. As endothelialization of prosthesis can be obtained in vivo after EC seeding and/or by transanastomotic, as well as by transprosthetic EC migrations, we have designed in vitro models to study the growth of EC seeded on PET, the EC colonization of an acellular area on PET, and the migration of EC from a collagen gel through the prosthesis. The combinations of either RGTA11 or heparin with FGF2 enhanced after a week by 5-fold the growth of seeded EC compared to RGTA or heparin alone and by 3-fold compared to FGF2 alone (p < 0.05). More than 80% of the colonization of an acellular area was achieved within 6 days when FGF2 was combined with RGTA11 or heparin. In contrast, colonization was only of 20% promoted in presence of FGF2 alone and not promoted in the presence of RGTA or heparin alone (p < 0.05). In addition, transprosthetic migration of EC and endothelialization of the luminal side were observed only when gel contained RGTA11 or heparin in combination with FGF2. The present work did strongly indicate that RGTA11 could be used in vivo as to improve endothelialization and should be the focus of continued investigation.

Adult↗
PubMed1997

Purification of an atypical bovine interferon induced in response to heat shock in bovine cultured cells. Characterization in comparison with the classical alpha, beta and gamma interferon.

Heat-shock induced factor (HSIF) was excreted by bovine MDBK cells during their recovery period after a heat shock. This factor has the capacity to induce 2',5' oligoadenylate synthetase activity, an enzyme generally by interferon treatment (J Biol Chem (1987) 262, 4806-4811). We have observed that an antiviral state was also produced in response to heat shock. HSIF was purified 10,000-fold and different techniques showed a copurification of both activities. Certain properties of HSIF were established, such as its molecular mass (45 kDa) and isoelectric point (6.8). This cytokine was acid-sensitive as IFN gamma (type II) and temperature labile contrarily to alpha, beta and gamma bovine IFN. Immunoprecipitation and comparative chromatography on lectines or polynucleotides established that HSIF was structurally different from the three classes of bovine IFN. Moreover, two-dimensional electrophoresis and comparative analysis of [35S] methionine-labeled proteins induced by HSIF alpha, beta or gamma bovine IFN showed that HSIF induces a specific set of proteins. Taken together, all these results strongly suggest that HSIF is a new atypical bovine interferon induced in response to heat shock.

2',5'-Oligoadenylate Synthetase↗
PubMed1996

The kinase inhibitor iso-H7 stimulates rat satellite cell differentiation through a non-protein kinase C pathway by increasing myogenin expression level.

We analysed the signaling pathways involved in myogenic differentiation of primary cultures of rat satellite cells using substances targeting the protein kinase C (PKC) and the cAMP protein kinase (PKA) pathways. We have previously shown that iso-H7, which putatively inhibits both PKC and PKA, strongly stimulates satellite cell differentiation, as well as the PKA inhibitor HA1004. In the study reported here, the effects of iso-H7 on satellite cell differentiation were compared to those observed in the presence of agents which reduce PKC activity. It was shown that treatments with the highly specific PKC inhibitor GF109203X or with 12-O-tetradecanoylphorbol 13-acetate (TPA) which induced a partial PKC downregulation, did not significantly alter myogenic differentiation. Northern blot analyses showed that iso-H7 activated the expression of myogenin but not that of MyoD mRNA. Concurrently, iso-H7 increased myosin light-chain mRNA expression. In contrast, TPA had no effect on these syntheses. Taken together, these results showed that iso-H7 did not act intracellularly as a PKC inhibitor but rather as a PKA inhibitor as previously suggested. Our results are compatible with the hypothesis that a reduction in PKA activity controls satellite cell myogenesis through an increased myogenin mRNA expression.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1995

Heparan-like molecules induce the repair of skull defects.

Heparin-binding growth factors (HBGFs) are known to stimulate bone repair when applied to bone lesions. Nevertheless, successful treatments are obtained with high protein doses since HBGFs are rapidly degraded in situ by multiple proteolytic activities associated with the inflammatory period of tissue healing. Like heparin or heparan sulfates, heparan-like molecules, named carboxymethyl-benzylamide-sulfonated dextrans (CMDBS), are known to potentiate fibroblast growth factor activities by stabilizing them against pH, thermal or proteolytic denaturations, and by enhancing their binding with cell surface receptors. We have postulated that CMDBS stimulate in vivo bone healing by interacting with endogenous HBGFs, spontaneously released in the wounded site. The effect of CMDBS on bone repair was studied in a skull defect model in rats by computer-assisted radio-morphometry and histomorphometry. Single application of CMDBS in a collagen vehicle to skull defects induced a dose-dependent increase in bone defect closure and new bone formation after 35 days. Complete bony bridging occurred in defects treated with 3 micrograms CMDBS, whereas bone formation was not observed in vehicle-treated defects which contained only dense fibrous connective tissue between the defect margins. These results indicate that heparan-like molecules, such as CMDBS, are able to induce bone regeneration of skull defects. This action is possibly mediated by potentiation of endogenous growth factor activities and/or by neutralization of proteolytic activities.

Animals↗
PubMed1995

[Effects of substituted dextran on reinnervation of a skeletal muscle in adult rats during regeneration].

RGTA11 is a chemically substituted dextran that mimics some of the properties of heparin or heparan sulphates towards heparin binding growth factors as well as inhibits some heparin binding proteases. In vivo RGTA11 has been shown to enhance muscle regeneration after crush. We now present evidence that RGTA11 can alos favour reinnervation of fast (EDL) as well as slow (soleus) crushed muscles. Both types of muscles were injected with RGTA11 after crushing and nerve cutting. In EDL muscles, after 16 days, motor end plates were more rapidly reformed and choline acetyl-transferase activity was 2 fold higher than in controls. In soleus muscles, after 16 days, motor end plates were reformed at normal size while controls were on average 30% smaller, the 16S form of acetyl-cholinesterase and choline acetyl-transferase activity were twice those of non injected regenerating controls. In conclusion, RGTA11 favours axonal growth and synaptic differentiation, allowing a more rapid reinnervation and maturation of the regenerated fibers. RGTA may present a new family of drugs against neuromuscular degenerescence.

Acetylcholinesterase↗
PubMed1993

Satellite cell myogenesis is highly stimulated by the kinase inhibitor iso-H7: comparison with HA1004 and staurosporine effects.

Differentiation of rat satellite cells, measured by cell fusion into myotubes and isozymic conversion of creatine kinase and phosphoglycerate mutase, was shown to be highly increased in the presence of 1-(5-isoquinolinylsulfonyl)-3-methylpiperazine (iso-H7). This substance inhibited both protein kinase C (PKC) and cAMP-dependent protein kinase (PKA) activities with similar IC50 between 22 and 34 microM. Iso-H7, as well as the PKA inhibitor HA1004 increased myogenic differentiation without altering the proliferation of satellite cells, whereas the proliferation and the differentiation of these cells were inhibited by the PKC inhibitor staurosporine. Our results suggest a predominant negative control of PKA on satellite cell myogenesis.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Improvement and simplification of low-background silver staining of proteins by using sodium dithionite.

High sensitivity and low background, the attractive characteristics of the procedure of Blum et al., Electrophoresis 1987, 8, 93-99, for silver staining of proteins in polyacrylamide gels have been improved by sensitizing the gels with sodium dithionite instead of sodium thiosulfate and by equilibration in water after fixation and prior to sensitization. These modifications decrease the background and allow for a longer development period, which in turn increases sensitivity and color contrast. In addition, the colors of the spots are shifted toward colder tones when compared with the original method.

Animals↗
PubMed1980

Multiple synostosis syndrome.

A 2-year-old deeply mentally handicapped girl is reported with a multiple synostosis syndrome, as delineated by Maroteaux et al. (1972). Besides the multiple synostoses the peculiar facial dysmorphism and the hearing deficit allow, the clinical diagnosis of this apparently rare syndrome.

Child, Preschool↗
PubMedDate not supplied

Stimulation of rat satellite cell myogenesis by inhibitors of ser/thr protein kinases.

Satellite cells are involved in physiological growth and post-traumatic regeneration of adult skeletal muscle fibres. In this study, it is shown that differentiation of primary cultures of rat satellite cells is increased by inhibitors of ser/thr protein kinases such as iso-H7, which both inhibit cAMP-dependent protein kinase (PKA) and protein kinase C (PKC) activities, and HA1004, a PKA inhibitor. These results, showing a preponderant effect of PKA inhibition on myogenesis in vitro, prompted the effects of iso-H7 on muscular regeneration in vivo to be tested. Preliminary results showed that regeneration of rat muscle EDL was improved by iso-H7 treatment.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗