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Biomedical subjects

P Gaudin

Publications and source records attributed to P Gaudin.

At least 37 records · Page 2Linked to original sources
PubMed1999

SAPHO syndrome or psoriatic arthritis? A familial case study.

OBJECTIVE: To discuss the relationships between SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome and the group of spondylarthropathies. METHODS: Few reports of familial SAPHO have been published. We describe three children, two sisters and one brother, whose clinical and radiological presentation was in accordance with SAPHO syndrome. RESULTS: Two children developed psoriasis, and one child palmoplantar pustulosis. Both sacroiliac and sternoclavicular joints were involved in these three cases. Some features in our observations are also common to psoriatic arthritis. No association was found with HLA antigens, but a history of trauma preceding the onset of symptoms was present in all three children. CONCLUSIONS: We can consider that SAPHO is nosologically related to spondylarthropathies. Psoriatic arthritis could be the missing link between SAPHO and spondylarthropathies. It is likely that both genetic and environmental factors are involved.

Acquired Hyperostosis Syndrome↗
PubMed1999

Rare expression of high-molecular-weight cytokeratin in adenocarcinoma of the prostate gland: a study of 100 cases of metastatic and locally advanced prostate cancer.

Immunohistochemistry with antibodies for high-molecular-weight cytokeratin labels basal cells and is used as an ancillary study in diagnosing prostate carcinoma, which reportedly lacks expression of high-molecular-weight cytokeratin. A recent report questioned the specificity of this marker, describing immunopositivity for high-molecular-weight cytokeratin in a small series of metastatic prostate cancer. We have also noted rare cases of prostate lesions on biopsy with typical histological features of adenocarcinoma showing immunopositivity for high-molecular-weight cytokeratin, either in tumor cells or in patchy cells with the morphology of basal cells. In some of these cases, it was difficult to distinguish cancer from out-pouching of high-grade prostatic intraepithelial neoplasia. To investigate whether prostate cancer cells express high-molecular-weight cytokeratin, we studied 100 cases of metastatic prostate carcinoma and 10 cases of prostate cancer invading the seminal vesicles from surgical specimens. Metastatic sites included regional lymph nodes (n = 67), bone (n = 19), and miscellaneous (n = 14). Cases with any positivity for high-molecular-weight cytokeratin antibody (34betaE12) were verified as being of prostatic origin with immunohistochemistry for prostate-specific antigen and prostate-specific acid phosphatase. Only four cases were detected positive for high-molecular-weight cytokeratin. In two cases (one metastasis, one seminal vesicle invasion) there was weakly diffuse positivity above background level. Two metastases in lymph nodes showed scattered strong staining of clusters of tumor cells, which represented <0.2% of tumor cells in the metastatic deposits. These positive cells did not have the morphology of basal cells. We conclude that prostate cancer, even high grade, only rarely expresses high-molecular-weight cytokeratin. This marker remains a very useful adjunct in the diagnosis of prostate cancer.

Acid Phosphatase↗
PubMed1999

Comparison of the 5-year outcome and morbidity of three-dimensional conformal radiotherapy versus transperineal permanent iodine-125 implantation for early-stage prostatic cancer.

PURPOSE: To compare the prostate-specific antigen (PSA) relapse-free survival outcome and incidence of late toxicity for patients with early-stage prostate cancer treated at a single institution with either three-dimensional conformal radiotherapy (3D-CRT) or transperineal permanent implantation (TPI) with iodine-125 seeds. MATERIALS AND METHODS: Patients with favorable-risk prostate cancer, defined as a pretreatment PSA of less than or equal to 10.0 ng/mL, Gleason score of 6 or lower, and stage less than or equal to T2b, were selected for this analysis. Between 1989 and 1996, 137 such patients were treated with 3D-CRT and 145 with TPI. The median ages of the 3D-CRT and TPI groups were 68 years and 64 years, respectively. The median dose of 3D-CRT was 70.2 Gy, and the median implant dose was 150 Gy. Prostate-specific antigen relapse was defined according to the American Society of Therapeutic Radiation Oncology Consensus Statement, and toxicity was graded according to the Radiation Therapy Oncology Group morbidity scoring scale. The median follow-up times for the 3D-CRT and TPI groups were 36 and 24 months, respectively. RESULTS: Eleven patients (8%) in the 3D-CRT group and 12 patients (8%) in the TPI group developed a biochemical relapse. The 5-year PSA relapse-free survival rates for the 3D-CRT and the TPI groups were 88% and 82%, respectively (P = .09). Protracted grade 2 urinary symptoms were more prevalent among patients treated with TPI compared with 3D-CRT. Grade 2 urinary toxicity, which was manifest after the implant and persisted for more than 1 year after this procedure, was observed in 45 patients (31%) in the TPI group. In these 45 patients, the median duration of grade 2 urinary symptoms was 23 months (range, 12 to 70 months). On the other hand, acute grade 2 urinary symptoms resolved within 4 to 6 weeks after completion of 3D-CRT, and the 5-year actuarial likelihood of late grade 2 urinary toxicity for the 3D-CRT group was only 8%. The 5-year actuarial likelihood of developing a urethral stricture (grade 3 urinary toxicity) for the 3D-CRT and TPI groups was 2% and 12%, respectively (P<.0002). Of 45 patients who developed grade 2 or higher urinary toxicity after TPI, the likelihood of resolution or significant improvement of these symptoms at 36 months from onset was 59%. The 5-year likelihood of grade 2 late rectal toxicity for the 3D-CRT and TPI patients was similar (6% and 11%, respectively; P = .97). No patient in either group developed grade 3 or higher late rectal toxicity. The 5-year likelihood of posttreatment erectile dysfunction among patients who were initially potent before therapy was 43% for the 3D-CRT group and 53% for the TPI group (P = .52). CONCLUSION: Both 3D-CRT and TPI are associated with an excellent PSA outcome for patients with early-stage prostate cancer. Urinary toxicities are more prevalent for the TPI group and subsequently resolve or improve in most patients. In addition to evaluating long-term follow-up, future comparisons will require detailed quality-of-life assessments to further determine the impact of these toxicities on the overall well-being and quality of life of the individual patient.

Adenocarcinoma↗
PubMed1999

Pathologic Handling and Reporting of Prostate Tissue Specimens in Patients Receiving Neoadjuvant Hormonal Therapy: Report of the Pathology Committee.

Prior meetings of the International Conference on Neoadjuvant Hormonal Therapy in Prostate Cancer identified areas of concern in the pathologic analysis of post-treatment specimens. In response, a pathology subcommittee was formed to address the questions that had been raised. Recommendations are made here concerning pretreatment biopsy review and reporting, handling and reporting of radical prostatectomy specimens, Gleason scoring of treated cancer, grading of therapy effect, role of immunohistochemistry procedures, and the significance of high-grade prostatic intraepithelial neoplasia. Neoadjuvant trials with both surgery and radiation therapy were considered in drawing up these recommendations.

Journal Article↗
PubMed1998

Human B lymphocytes synthesize the 92-kDa gelatinase, matrix metalloproteinase-9.

Matrix metalloproteinases (MMPs) are involved in the remodeling of connective tissue as well as in disease states associated with acute and chronic inflammation or tumoral metastatic processes. Despite detailed and extensive studies of the mechanisms of lymphocyte extravasation, remarkably little is known about the expression and regulation of metalloproteinases involved in the migratory process. By using zymography and reverse transcription-polymerase chain reaction experiments, we have demonstrated that Epstein-Barr virus-immortalized B lymphocytes are able to secrete a 92-kDa metalloproteinase with gelatinolytic activity which has been purified and identified as being MMP-9. Moreover, the tissue inhibitor of metalloproteinase was shown to be constitutively expressed by the B cells. The expression of 92-kDa gelatinase is mediated by cytokines, growth factors, lipopolysaccharide, concanavalin A, and the tumor promotor phorbol 12-myristate 13-acetate. Time dependence activity increased rapidly up to 24 h of incubation with lipopolysaccharide or concanavalin A stimulation while it requires a delay and more time to have an optimum effect when cytokines were the stimulating agents; transforming growth factor-beta abolished 92-kDa gelatinase production. Both staurosporine and wortmannin are inductive stimuli, and the level of MMP-9 secreted into the media is greater than that observed with other agents except concanavalin A. Elicitation of the chemotactic migration of B cells through a model basement membrane by lipopolysaccharide was shown to be correlated with gelatinase expression and inhibited by 7 mM captopril. Our study indicates that Epstein-Barr virus-B lymphocytes express 92-kDa gelatinase, the production of which can be modified by a variety of physiological and pharmacological signals which have been shown to differ according to the cell type.

Androstadienes↗
PubMed1998

Constitutive activation of the human vasoactive intestinal peptide 1 receptor, a member of the new class II family of G protein-coupled receptors.

The human vasoactive intestinal peptide (VIP) 1 receptor belongs to the new class II subfamily of G protein-coupled receptors. Specific change by mutagenesis of a strictly conserved histidine into arginine at position 178 of the human VIP1 receptor resulted in its constitutive activation with respect to cAMP production. Transfection of the H178R mutant into COS cells resulted in a 3.5-fold increase in the cAMP level as compared with cells transfected with the wild type receptor or the vector alone. This increase was proportional to the amount of transfected cDNA. The H178R mutant exhibited an otherwise normal cAMP response to VIP as well as a dissociation constant similar to that of the wild type receptor. Other mutants at position 178 such as H178K, H178A, and H178D were not constitutively activated. They were otherwise expressed at the cell surface of transfected nonpermeabilized cells. Double mutants were then constructed in which the H178R mutation was associated with a point mutation in the the N-terminal extracellular domain that totally abolished VIP binding or VIP-stimulated cAMP production, i.e. E36A or D68A. The corresponding double mutants H178R/E36A and H178R/D68A were no longer constitutively activated. A control double mutant (H178R/D132A) with an unaltered dissociation constant for VIP and cAMP response to VIP was still constitutively activated. Our findings demonstrate that constitutive activation of the VIP1 receptor by mutation of His178 into R requires the functional integrity of the N-terminal extracellular VIP binding domain. They might provide interesting generalities about the activation process of G protein-coupled receptors.

Animals↗
PubMed1997

Proteolytic potential of human neutrophil membranes.

A synergistic role for proteases in the degradation of extracellular matrix proteins has been proposed. Plasma membrane was isolated from a neutrophil homogenate, on a sucrose gradient, and shown to activate gelatinolysis when purified 92 kDa gelatinase was added to the medium. This stimulatory activity was enhanced by the addition of phorbol 12-myristate 13-acetate (PMA), in a dose-dependent manner, and was partially sensitive to phenylmethylsulfonyl fluoride treatment. The effect was abolished by the addition of 1 M KCl or 0.05% Brij 35 extraction. Both elastase and urinary type plasminogen activator were shown to be involved in the process. Moreover, upon neutrophil stimulation by PMA, 92 kDa gelatinase, as elastase, became associated with the plasma membrane, as shown by a subcellular fractionation experiment. These in vitro observations suggest that human neutrophils may be able, in vivo, to recruit endogenous or exogenous proteinases to mediate proteolysis associated with diapedesis and chemotactism during the inflammation process.

Alkaline Phosphatase↗
PubMed1997

A study of metalloproteinases in fifty joint fluid specimens.

OBJECTIVES: To study the activity and concentrations in joint fluid of gelatinases (A or matrix metalloproteinase (MMP)-2 and B or MMP-9), tissue inhibitor of metalloproteinases 1 (TIMP-1), and stromelysin-1 (MMP-3). METHODS: Synovial fluid specimens obtained as part of a diagnostic or therapeutic procedure were studied. Protein levels were determined, cells counted, crystals looked for and microbiological studies done. Gelatinolytic activity was determined quantitatively using computerized zymography. Proteins were identified by electrotransfer and immunorevelation. TIMP-1 and stromelysin-1 were assayed using an ELISA. Results were confronted with laboratory test and clinical findings. RESULTS: Of the 50 specimens studied, 25 were from joints with mechanical disorders and 25 from joints with inflammatory disorders. Activated MMP-2 was found in all the specimens, with no differences between the two groups. MMP-9 was found only in its inactive form. MMP-9, TIMP-1 and MMP-3 were found more often in inflammatory than in mechanical fluids and the levels of MMP-9 and TIMP-1 were correlated with neutrophil counts. In the 16 fluids from rheumatoid arthritis patients, levels of MMP-9 and TIMP-1 were closely correlated with serum C-reactive protein levels. CONCLUSIONS: MMP-9, TIMP-1, and MMP-3 levels show striking differences between inflammatory and mechanical joint fluids.

Adolescent↗
PubMed1996

Vasoactive intestinal peptide (VIP)1 receptor. Three nonadjacent amino acids are responsible for species selectivity with respect to recognition of peptide histidine isoleucineamide.

Vasoactive intestinal peptide (VIP)1 receptors in rats and humans recognize peptide histidine isoleucineamide (PHI) with high and low affinity, respectively. We took advantage of this phenotypic difference to identify the domain responsible for the selective recognition of PHI by rat and human receptors which display >80% sequence identity. After transfection of human and rat receptors in COS cells, the ratio of IC50 for PHI/IC50 for VIP (referred to as P/V) in inhibiting 125I-VIP binding was shown to be >1,000 and <40, respectively. Construction of eight rat/human receptor chimerae by overlap polymerase chain reaction and determination of their P/V ratios demonstrated that the critical domain for PHI recognition is present within a sequence comprising part of the first extracellular loop and third transmembrane domain. This domain contains three different amino acids numbered according to human and rat sequences, respectively, e.g. Gln207 (human) versus His208 (rat), Gly211 versus Ala212 and Met219 versus Val220. Site-directed mutagenesis introducing individual, double, or triple mutations in a chimeric construct revealed that all three amino acids were involved in the recognition of PHI. Triple mutations were then introduced in the wild-type receptors i.e. Q207H, G211A, M219V human VIP1 receptor and H208Q, A212G, V220M rat VIP1 receptor, resulting in a complete change in their phenotype from human to rat and from rat to human, respectively. The results demonstrate that three nonadjacent amino acids are responsible for the selective recognition of PHI by human and rat VIP1 receptors.

Amino Acid Sequence↗
PubMed1996

Stable expression of the recombinant human VIP1 receptor in clonal Chinese hamster ovary cells: pharmacological, functional and molecular properties.

We stably transfected Chinese hamster ovary (CHO) cells with the recombinant human vasoactive intestinal peptide (VIP)1 receptor. A clone referred to as Clone 15 was isolated and studied for receptor properties. The following data were obtained: (1) one class of binding site was identified by Scatchard analysis of [125I]VIP binding to cell membranes with a Kd of 0.41 nM and a Bmax of 1.62 pmol/mg protein; (2) the constant Ki for the inhibition of [125I]VIP binding by VIP and related peptides was: VIP (0.9 nM) = pituitary adenylate cyclase-activating peptide (PACAP)-27 (1.3 nM) < PACAP-38 (6.8 nM) < helodermin (46.0 nM) < human growth hormone-releasing factor (GRF) (0.6 microM) < peptide histidine methionineamide (2.0 microM) < secretin (> 10 microM); (3) cross-linking experiments using [125I]VIP identified a single M(r) 67000 recombinant receptor; (4) VIP stimulated cAMP production in Clone 15 cells with an EC50 of 0.20 nM; (5) some previously described VIP receptor antagonists including [4-Cl-D-Phe6, Leu17]VIP, [Ac-Tyr1,D-Phe2]GRF-(1-29) amide and VIP-(10-28) inhibited [125I]VIP binding with a Ki of 0.7, 1.6 and 2.5 microM, respectively. They failed to stimulate cAMP production in Clone 15 cells and inhibited, at least partially, the VIP (0.3 nM)-evoked cAMP production; (6) exposure of Clone 15 cells to 10 nM VIP for 24 h resulted in a sharp decrease in Bmax in Clone 15 cells (0.43 vs. 1.62 pmol/mg protein in control cells) and in the potency and efficacy of VIP in stimulating cAMP. Moreover, immunofluorescence studies using confocal microscopy indicated that the receptor was internalized and sequestered in vesicular structures within the cells. It is concluded that Clone 15 cells provide a valuable tool to further characterize various functional and pharmacological aspects of the human VIP1 receptor.

Animals↗
PubMed1996

Mutagenesis of N-glycosylation sites in the human vasoactive intestinal peptide 1 receptor. Evidence that asparagine 58 or 69 is crucial for correct delivery of the receptor to plasma membrane.

The functional role of N-linked carbohydrates in the human vasoactive intestinal peptide (VIP) 1 receptor was investigated by site-directed mutagenesis (Asn-->Thr) of the four consensus N-glycosylation sites on Asn58, Asn69, Asn100 (N-terminal extracellular domain) and Asn293 (second extracellular loop). Mutated receptors were investigated after transient expression in Cos-7 cells, by ligand binding assay, affinity cross-linking, western blotting, and confocal laser microscopy of epitope-tagged receptor proteins. Mutations of each consensus site revealed that Asn58, Asn69, and Asn100 were occupied by a 9-kDa N-linked carbohydrate whereas Asn293 was not used for glycosylation. Each mutated receptor was expressed (western blot) and delivered at the plasma membrane (confocal microscopy) of Cos-7 cells. They displayed a dissociation constant similar to that of the wild-type receptor, i.e., 0.5-1 nM. In contrast, no VIP binding to Cos-7 cells could be observed with the mutant devoid of consensus N-glycosylation sites due to a strict sequestration of this mutant in the perinuclear endoplasmic reticulum. However, when solubilized with a zwitterionic detergent, this mutant bound [125I]VIP specifically, indicating that it retained intrinsic binding activity. The construction of other mutants in which three out of four N-glycosylation sites were altered, demonstrated that N-glycosylation at either Asn58 or Asn69 is necessary and sufficient to ensure correct delivery of the receptor to the plasma membrane. Further pharmacological studies involving incubation of Cos-7 cells with castanospermine or deoxymannojirimycin immediately after transfection of mutated cDNAs encoding receptors with a single glycosylation site at Asn58 or Asn69 suggested that carbohydrate at Asn58 was involved in a calnexin-dependent folding process of the receptor whereas carbohydrate at Asn69 was not. These studies highlight the functional importance of the N-glycosylation of the human VIP 1 receptor which belongs to a new subfamily of seven membrane-spanning receptors.

Amino Acid Sequence↗
PubMed1996

[Twenty one years of hemodialysis in a patient with primary hyperoxaluria].

We report a male patient with primary hyperoxaluria from childhood who survived more than 21 years on conventional haemodialysis. Despite the severity of his bone disease, he was married and actively employed up until 2 years before his death. His condition really worsened a few months before his death. He presented with only renal and bone involvement and had hardly any cardiovascular complications, that was probably a reason for his prolonged survival. Such an evolution is very unusual and we speculate that the length of haemodialysis sessions in addition to the large surface of the membrane probably contributed to such an outcome. During the time period on HD, anemia was transiently controlled by recombinant erythropoietin despite oxalate involvement of the marrow. He was refused a liver-kidney transplant and died from malnourishment at 43 years of age. To our knowledge, such an outcome has not yet been reported. It shows that careful prolonged hemodialysis sessions should be helped in admet patients without severe cardiovascular involvement.

Adult↗
PubMed1995

Mutational analysis of cysteine residues within the extracellular domains of the human vasoactive intestinal peptide (VIP) 1 receptor identifies seven mutants that are defective in VIP binding.

We have used site-directed mutagenesis to investigate the requirement of cysteine residues in the extracellular domains of the human VIP 1 receptor for binding VIP. Cys37, Cys50, Cys63, Cys72, Cys86, Cys105 and Cys122 (N-terminal extracellular domain), Cys208 and Cys215 (second extracellular loop) and Cys288 (third extracellular loop) were mutated into glycine, and mutated cDNAs transfected into Cos-7 cells. It appeared that mutants C50G, C63G, C72G, C86G, C105G, C122G, and C288G did not bind VIP whereas mutants C37G, C208G and C215G bound VIP with the same dissociation constant (#0.5 nM) as the wild-type receptor. All mutated receptor proteins were synthesized by Cos-7 cells (Western blot) and delivered at the plasma membrane level (confocal microscopy). The fact that C208G and C215G mutants retained a complete binding activity while the C288G mutant was inactive does not suggest the presence of a functionally relevant disulfide bond between the second and third extracellular loop of the human VIP receptor contrary to what has been shown in several other heptahelical receptors. It is also concluded that the six crucial cysteine residues, e.g., Cys50, Cys63, Cys72, Cys86, Cys105 and Cys122 in the N-terminal extracellular domain, may be functionally important by forming intramolecular disulfide bonds which help to maintain the topology for ligand binding in human VIP 1 receptors.

Amino Acid Sequence↗