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Biomedical subjects

C Vincent

Publications and source records attributed to C Vincent.

At least 37 records · Page 2Linked to original sources
PubMed2004

Rheumatoid factor and anticitrullinated protein antibodies in rheumatoid arthritis: diagnostic value, associations with radiological progression rate, and extra-articular manifestations.

BACKGROUND: Autoantibodies such as rheumatoid factor (RF) and anticitrullinated protein antibodies can be detected in rheumatoid arthritis (RA) sera. OBJECTIVE: To determine the diagnostic values of RF, anticitrullinated protein antibodies, and the shared epitope (SE), and their associations with radiological progression rates and extra-articular manifestations. METHODS: Population 1 consisted of sera from 315 patients, consecutively sent for detection of anticitrullinated protein antibodies, of which 264 were used to determine the sensitivity and specificity of RF and of antibodies against three synthetic citrullinated peptides: peptide A (pepA), peptide B (pepB), and CCP2. Population 2 consisted of sera from 180 longstanding RA patients and was used to determine associations of RA associated antibodies and the SE with radiological progression rates and extra-articular manifestations. Antibodies to pepA and pepB were detected by line immunoassay, and antibodies to CCP2 by ELISA. HLA Class II typing was performed by LiPA. RESULTS: In population 1, we defined adapted cut offs corresponding to a specificity of >/=98.5%. This yielded the following sensitivities: RF 12.8%; anti-pepA antibodies 63.6%; anti-pepB antibodies 54.2%; and anti-CCP2 antibodies 73.7%. In population 2, significant differences in radiological progression rates were found between positive and negative patients for different RA antibodies and the SE. RF, but not anticitrullinated protein antibodies or the SE, were more frequent in patients with extra-articular manifestations. CONCLUSION: A valid comparison of RA associated antibodies shows superior sensitivity of the anticitrullinated protein antibodies compared with RF. The presence of RA associated antibodies and the SE are indicative for poorer radiological outcome, and presence of extra-articular manifestations is associated with RF but not with anticitrullinated protein antibodies.

Adult↗
PubMed2004

The simulated operating theatre: comprehensive training for surgical teams.

Surgical excellence is traditionally defined in terms of technical performance, with little regard for the importance of interpersonal communication and leadership skills. Studies in the aviation industry have stressed the role of human factors in causing error and, in an attempt to reduce the occurrence of adverse events, led to the organisation of simulation based training scenarios. Similar strategies have recently been employed for the surgical team with the development of a simulated operating theatre project. This enables technical and non-technical performance of the surgeon and circulating staff to be assessed by experts situated in an adjacent control room, and provides an opportunity for constructive feedback. The scenarios have good face validity and junior surgeons can benefit from the process of learning new technical skills in a realistic environment. The effect of external influences such as distractions, new technology, or a crisis scenario can also be defined, with the ultimate aim of reducing the number of adverse events arising in the real operating room.

Clinical Competence↗
PubMed2003

Comparative studies on the secretion and activation of MMPs in two reconstructed human skin models using HaCaT- and HaCaT-ras-transfected cell lines.

Matrix metalloproteinases play an important role in tissue regeneration, wound healing and tumor invasion. Our previous studies have shown a higher motility of HaCaT-ras-transfected cells compared with HaCaT or normal human keratinocytes (NHK) in correlation with a higher secretion of MMP-2 (72 kDa) or MMP-9 (92 kDa), according to the medium used for cell cultures. Presently, the expression and activity of MMPs were investigated in two reconstructed skin models, using a dead de-epidermized dermis (DED) or a dermal substitute including living fibroblasts. In all experiments, MMP-9 was essentially secreted by NHK and to a greater extent by HaCaT cells. Its active form (86 kDa) was only detected in both reconstructed skin models according to keratinocyte differentiation. MMP-2 was mainly secreted by living fibroblasts included in the dermal substitute skin model. In this case, its activation was up-regulated when HaCaT cell lines were seeded onto the dermal substitute according to their culture at air/liquid interface as shown for MMP-9. The collagenase MMP-1 and stromelysin-1 (MMP-3), susceptible to activate pro-MMP-2 and -9, respectively, were detected in their inactive form by ELISA. MMP-1 was expressed in both models but MMP-3 required the presence of living fibroblasts. Their activities were not detected using specific fluorogenic substrates. In the skin equivalent model using HaCaT, the extensive secretion and activation of MMP-2 and MMP-9 could explain the defect observed in basal membrane reconstruction, suggesting a direct interaction of HaCaT with fibroblasts.

Cell Culture Techniques↗
PubMed2003

Withdrawal of TNF-alpha after the fifth day of differentiation of CD34+ cord blood progenitors generates a homogeneous population of Langerhans cells and delays their maturation.

Human cord blood CD34+ progenitors cultured in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) generate a heterogeneous population of dendritic cells (DC), including Langerhans cells (LC). This combination of cytokines has been shown to be crucial for differentiation into LC. After day 5 of culture, TNF-alpha has been maintained in the medium in most studies despite the observation of spontaneous maturation of LC after day 12. Five-day samples of in vitro differentiated LC were cultured in parallel with or without TNF-alpha. The absence of TNF-alpha was shown to: (1) slow down proliferation without triggering apoptotic cell death, (2) enhance the percentage of LC, (3) delay or abrogate the expression of CD83, CD86, HLA-DR and CD208 molecules, and (4) maintain endocytosis by receptor and macropinocytosis. The withdrawal of TNF-alpha abrogated the spontaneous synthesis of matrix metalloproteinases. At day 12, TNF-alpha-deprived LC were less efficient in allogeneic T cell activation than LC cultivated with TNF-alpha. These data indicate that the suppression of TNF-alpha after day 5 maintains cells in an immature state and provides a population with 80% of LC at day 12.

Antigens, CD34↗
PubMed2003

High-dose BCNU followed by autologous hematopoietic stem cell transplantation in supratentorial high-grade malignant gliomas: a retrospective analysis of 114 patients.

Conventional treatment of high-grade glioma includes maximal surgical resection followed by external radiation therapy. Despite this treatment, the prognosis for patients is poor. High doses of chemotherapy might be another way to increase the response rate and median survival. Increasing doses of BCNU might be more effective, but also provokes unacceptable myelotoxicity. This dose-limiting toxicity can be circumvented by using autologous blood stem cell rescue. We report our experience of high-dose BCNU followed by transplantation of autologous hematopoietic stem cells in 114 patients with high-grade gliomas. Of the 114 gliomas, 78 were glioblastoma multiforme (GM) (68%), 24 anaplastic astrocytomas (AA) (21%), and 12 anaplastic oligodendrogliomas (OD) (11%). Complete surgical resection was performed for 22 patients (18 GM and 4 AA). The median age was 44 years (range 17-65). A total of 84 patients received autologous hematopoietic stem cells from bone marrow harvest, while 30 patients received granulocyte colony-stimulating factor followed by apheresis and received peripheral blood progenitor cells (PBPC). High dose of BCNU (800 mg/m(2)) was given at least 1 month after neurosurgery. Bone marrow or PBPC was transplanted 48-72 h after chemotherapy. Radiotherapy was started approximately 40 days after transplantation to a total of 60 Gy. Median follow-up was 89 months (19-163). The overall survival (OS) was, respectively, 12 months for GM, 37 months for OD and 81 months for AA. Histological type appeared to be the main discriminating factor, with a worse prognosis for GM. Within the GM population, age, completeness of surgery, and response appeared to be one important prognostic factors. The AA and OD populations were small to reliably assess prognostic factors. On multivariate analysis, the main prognostic factors were histologic type, quality of surgery, and age (P<0.005). Five of 114 patients had lethal complications from the procedure. Four of these patients had a Karnovsky performance score (KPS) of 60%. The protocol thus appears to be feasible but patients should be selected for KPS more than 70%. We observed long-term survivors, although the OS and the time to treatment failure seem to be comparable to that described for other treatment. Additional pilot studies are unlikely to reveal more than a modest benefit from this procedure and therefore a randomized study should be performed.

Adolescent↗
PubMed2003

Binding of live conidia of Aspergillus fumigatus activates in vitro-generated human Langerhans cells via a lectin of galactomannan specificity.

Aspergillus fumigatus is the most common aetiological fungus responsible for human pulmonary aspergilloses. This study investigated the primary contact between Langerhans cells (LC), corresponding to dendritic cells present in pulmonary mucosa and live conidia of A. fumigatus. LC play a key role in antigen presentation for initiation of the primary T cell response. In vitro-generated LC (iLC) were differentiated from cultured human cord blood CD34+ cells and incubated at 4 degrees C or 37 degrees C with fluorescein-isothiocyanate (FITC)-stained conidia or control latex beads. In vitro, conidia were shown by microscopy and cytometry to adhere to iLC in a dose- and time-dependent manner. This adhesion was not limited to iLC because interstitial dendritic and other cells also fluoresced in the presence of conidia-FITC. A lectin other than mannose receptor-type lectin was demonstrated to be responsible of conidial binding. Inhibition of binding was observed with heterologous galactomannan and EDTA, indicating a C-lectin-like receptor with galactomannan structure specificity. After binding only a few conidia were internalized in acidic vesicles, as indicated by the cessation of conidial fluorescence. Conidial binding was followed by activation and maturation of iLC, suggesting that LC present in the lung may play a role in cellular host defence against aspergilloses.

Aspergillosis↗
PubMed2003

Case record review of adverse events: a new approach.

OBJECTIVES: To redesign the existing clinical review form (RF2) used in previous retrospective case record review studies in order to clarify the review process and provide a more powerful analysis of adverse events; and then to ask clinicians to pilot and evaluate the new modular review form (MRF2). The review form is divided into five sections, each with a defined purpose, providing a modular structure. DESIGN: Design and testing of the MRF2 on a sample of medical and nursing records, and evaluation of the reviewers' responses regarding the new review form. SETTING: Hospital based teams from eight countries. RESULTS: The modular review form was reported to be comprehensive, well structured, and clear. Most of the reviewers agreed with the positive statements regarding the review form. Overall, the modular structure was thought to be helpful. Several modifications have been made to the final version to take account of criticisms and suggestions. CONCLUSIONS: The full potential of case record review has yet to be explored. The benefits of this review form include a modular format which enables reviewers or project leaders to select the focus of their review based on resources and the purpose of the review, and to identify contributory factors which indicate areas for improvement and prevention. The training of reviewers is of vital importance for record review. Record review remains one of the primary methods for assessing the incidence of adverse events and the new format is suitable for both prospective and retrospective review.

Attitude of Health Personnel↗
PubMed2002

Isolation and characterization of a protein-tyrosine kinase and a phosphotyrosine-protein phosphatase from Klebsiella pneumoniae.

Two proteins of Klebsiella pneumoniae, termed Yor5 and Yco6, were analyzed for their capacity to participate in the reversible phosphorylation of proteins on tyrosine. First, protein Yco6 was overproduced from its specific gene and purified to homogeneity by affinity chromatography. Upon incubation in the presence of radioactive adenosine triphosphate, it was found to effectively autophosphorylate. Two-dimensional analysis of its phosphoamino acid content revealed that it was modified exclusively at tyrosine. Second, protein Yor5 was also overproduced from the corresponding gene and purified to homogeneity by affinity chromatography. It was shown to contain a phosphatase activity capable of cleaving the synthetic substrate p-nitrophenyl phosphate into p-nitrophenol and free phosphate. In addition, it was assayed on individual phosphorylated amino acids and appeared to dephosphorylate specifically phosphotyrosine, with no effect on phosphoserine or phosphothreonine. Such specificity for phosphotyrosine was confirmed by the observation that Yor5 was able to dephosphorylate protein Yco6 previously autophosphorylated. Together, these data demonstrate that similarly to other bacterial species including Acinetobacter johnsonii and Escherichia coli, the cells of K. pneumoniae contain both a protein-tyrosine kinase and a phosphotyrosine-protein phosphatase. They also provide evidence that this phosphatase can utilize the kinase as an endogenous substrate, which suggests the occurrence of a regulatory mechanism connected with reversible protein phosphorylation on tyrosine. Since Yco6 and Yor5 are both involved in the synthesis of capsular polysaccharide and since capsules are essential to the virulence of K. pneumoniae, we suggest that reversible protein phosphorylation on tyrosine may be part of the cascade of reactions that determine the pathogenicity of bacteria.

Amino Acid Sequence↗
PubMed2002

Allogeneic hematopoietic stem cell transplantation in ovarian carcinoma: results of five patients.

Allogeneic hematopoietic stem cell transplantation is often used to treat hematologic malignancies. The efficacy of this procedure is due to both myeloablative conditioning and graft-versus-leukemia (GVL). However, the disadvantages of allogeneic transplantation include graft-versus-host disease (GVHD), relapse from the original tumor, and patient susceptibility to opportunistic infections. Lately, allogeneic transplantation has been developed to treat solid tumors, with the expectation that graft-versus-tumor (GVT), like GVL, will have a significant anti-tumor effect. This effect has been demonstrated in renal carcinomas, and with less evidence in breast cancers. Five patients with malignant ovarian tumors resistant to chemotherapy underwent allogeneic transplantation, four from bone marrow, and one from peripheral blood stem cells. All donors were HLA-identical siblings. One patient received a myeloablative conditioning regimen, while the other four received a non-myeloablative regimen. Two patients received donor lymphocyte infusions (DLI). Four of the patients presented with acute or chronic GVHD associated with tumor regression of at least 50%. These tumor regressions were measured by CA-125 levels and CT scans. The fifth patient died of rapid progression just after transplantation. Of the four transplantation survivors, three received a non-myeloablative regimen which did not seem to reduce treatment effectiveness. While it did reduce toxicity, one of these patients died of GVHD after 127 days. DLI was administered to two patients. These infusions seemed to promote GVHD which was able to control disease progression for one patient and had no apparent effect on the other. Allograft of hematopoietic stem cells might be of interest in ovarian cancer. The results in one patient also suggest that DLI may be an effective immunotherapy, although doses and timing need to be determined. The number of cases presented is small, however, and clinical experience on a larger scale will be required to determine the real clinical efficacy of graft versus cancerous ovarian cells.

Adult↗
PubMed2002

Prescribing errors in hospital inpatients: their incidence and clinical significance.

BACKGROUND: It has been estimated that 1-2% of US inpatients are harmed by medication errors, the majority of which are errors in prescribing. The UK Department of Health has recommended that serious errors in the use of prescribed drugs should be reduced by 40% by 2005; however, little is known about the current incidence of prescribing errors in the UK. This pilot study sought to investigate their incidence in one UK hospital. METHODS: Pharmacists prospectively recorded details of all prescribing errors identified in non-obstetric inpatients during a 4 week period. The number of medication orders written was estimated from a 1 in 5 sample of inpatients. Potential clinical significance was assessed by a pharmacist and a clinical pharmacologist. RESULTS: About 36200 medication orders were written during the study period, and a prescribing error was identified in 1.5% (95% confidence interval (CI) 1.4 to 1.6). A potentially serious error occurred in 0.4% (95% CI 0.3 to 0.5). Most of the errors (54%) were associated with choice of dose. Error rates were significantly different for different stages of patient stay (p<0.0001) with a higher error rate for medication orders written during the inpatient stay than for those written on admission or discharge. While the majority of all errors (61%) originated in medication order writing, most serious errors (58%) originated in the prescribing decision. CONCLUSIONS: There were about 135 prescribing errors identified each week, of which 34 were potentially serious. Knowing where and when errors are most likely to occur will be helpful in designing initiatives to reduce them. The methods developed could be used to evaluate such initiatives.

Delphi Technique↗
PubMed2002

Antagonistic effects of IL-4 and TGF-beta1 on Langerhans cell-related antigen expression by human monocytes.

In this study, we analyzed the specific effects of transforming growth factor beta (TGF-beta1) and/or IL-4 on monocyte-derived cells. Monocytes were cultured with GM-CSF, GM-CSF/TGF-beta1, GM-CSF/IL-4, or GM-CSF/IL-4/TGF-beta1 before cell morphology, phenotype, and function were assessed. As expected, interleukin-4 is mandatory for monocyte differentiation into potent allostimulatory DC. In its absence, monocyte-derived cells share many phenotypic and functional features with macrophages. However, it is interesting that the cells express E-cadherin, independent of exogenous TGF-beta1, and addition of the cytokine induced CCR6 expression. Most importantly, a subset of monocytes cultured with GM-CSF/TGF-beta1 expresses Langerin, as confirmed by electron microscopy analysis. Langerin engagement with specific monoclonal antibodies induces its internalization and the formation of typical Birbeck granules. Monocytes cultured in GM-CSF/IL-4 did not express the LC markers E-cadherin, CCR6, or Langerin. The simultaneous addition of TGF-beta1 allows most of the cells to express E-cadherin but rarely CCR6 and Langerin. Taken together, the results add further evidence that LC can derive from monocytes and demonstrate an antagonistic effect of IL-4 and TGF-beta1 on monocyte differentiation toward the LC pathway.

Antigens, CD↗
PubMed2002

[Frontal sinus osteomas: neuro-ophthalmological complications].

Osteomas are the most frequent benign tumors of the paranasal sinuses. They often grow in the frontal sinus near the nasofrontal duct. They remain frequently asymptomatic and they tend to be an incidental finding on radiographic studies. Rarely, they extend out of the sinus limits. Two cases with neuro-ophthalmological complications are reported and discussed. A 19-year-old female presented with a progressive left visual impairment and orbital bone deformity. A CT-scan revealed a large calcified mass in both frontal sinuses, with left intraorbital and frontobasal extension. A 21-year-old man suffered from acute frontoethmoidal sinusitis. Radiological exams revealed a right frontal sinus osteoma with bilateral nasofrontal ducts obstruction. The frontal sinus cavities were filled with a large mucocele with intracranial extension. Both patients were successfully treated using frontobasal craniotomy with complete osteoma and mucocele removal and cranio facial bone reconstruction. Neuro-ophthalmological or intrasinusal complications of osteomas lead to radical treatment. CT-scan and MRI analysis for surgical purpose and strategy are emphased.

Adult↗
PubMed2002

[Clinical implications of acoustic neuromas growth rate in volumetric study].

OBJECTIVE: The pattern of neuroma growth is of great importance in choosing the appropriate management. This paper tests the clinical impact of tumor growth rate assessed by volumetry. There is a conviction that some slowly growing tumors could be observed for many years. METHOD AND PATIENTS: Volume measurements were performed on T1- weighted MR images (spin echo sequences) after injection of gadolinium using a special dedicated software. The studied group included 17 patients in whom at least two MRI examinations were carried out and tumor growth was confirmed. The intervals between initial and the first follow-up examination were 14.2 months on the average. In 7 cases tumor evolution was observed in 2 periods (3 MRI studies) and in 4 cases in 3 periods (4 MRI studies). RESULTS: The growth rate depended on tumors volume and clinical stage (P<0.01). Small tumors can be observed more safely than advanced tumors because their increase in mass is lower. CONCLUSION: The observation with the tumoral volume measurements appears to be a useful and accurate tool to estimate the tumor growth rate. The growth rate is a major factor for choosing the appropriate management.

Follow-Up Studies↗
PubMed2001

A novel MADS-box gene subfamily with a sister-group relationship to class B floral homeotic genes.

Class B floral homeotic genes specify the identity of petals and stamens during the development of angiosperm flowers. Recently, putative orthologs of these genes have been identified in different gymnosperms. Together, these genes constitute a clade, termed B genes. Here we report that diverse seed plants also contain members of a hitherto unknown sister clade of the B genes, termed B(sister) (B(s)) genes. We have isolated members of the B(s) clade from the gymnosperm Gnetum gnemon, the monocotyledonous angiosperm Zea mays and the eudicots Arabidopsis thaliana and Antirrhinum majus. In addition, MADS-box genes from the basal angiosperm Asarum europaeum and the eudicot Petunia hybrida were identified as B(s) genes. Comprehensive expression studies revealed that B(s) genes are mainly transcribed in female reproductive organs (ovules and carpel walls). This is in clear contrast to the B genes, which are predominantly expressed in male reproductive organs (and in angiosperm petals). Our data suggest that the B(s) genes played an important role during the evolution of the reproductive structures in seed plants. The establishment of distinct B and B(s) gene lineages after duplication of an ancestral gene may have accompanied the evolution of male microsporophylls and female megasporophylls 400-300 million years ago. During flower evolution, expression of B(s) genes diversified, but the focus of expression remained in female reproductive organs. Our findings imply that a clade of highly conserved close relatives of class B floral homeotic genes has been completely overlooked until recently and awaits further evaluation of its developmental and evolutionary importance. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00438-001-0615-8.

Amino Acid Sequence↗