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Biomedical subjects

C Vincent

Publications and source records attributed to C Vincent.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Pendred's syndrome. Current features].

Introduction Pendred's syndrome is a recessive autosomal disease, traditionally defined as the association of deaf-mutism, goiter and dysfunctional iodide organization revealed by the perchlorate discharge test. It represents 4 to 10% of the causes of congenital hypoacusis. Although described more than a 100 years ago, the association of thyroid and cochleo-vestibular damage remained unclear for many years. Genetic abnormalities Progress in molecular biology has revealed that the disease is related to alterations in the PDS gene situated on chromosome 7. The PDS gene is responsible for the production of pendrine, protein involved in anion (l-, Cl-) transportation, notably in the apical pole of the thyreocyte and the cochlear duct, where the endolympha is produced. Practical implications The truncation of pendrine related to the genetic alterations be responsible for the morpho-functional alterations in the cochlear apparatus and the thyroid. In this perspective, Pendred's syndrome would appear as a genetic disorder in anion transportation.

Carrier Proteins↗
PubMed2001

Immature human dendritic cells express asialoglycoprotein receptor isoforms for efficient receptor-mediated endocytosis.

In a search for genes expressed by dendritic cells (DC), we have cloned cDNAs encoding different forms of an asialoglycoprotein receptor (ASGPR). The DC-ASGPR represents long and short isoforms of human macrophage lectin, a Ca(2+)-dependent type II transmembrane lectin displaying considerable homology with the H1 and H2 subunits of the hepatic ASGPR. Immunoprecipitation from DC using an anti-DC-ASGPR mAb yielded a major 40-kDa protein with an isoelectric point of 8.2. DC-ASGPR mRNA was observed predominantly in immune tissues. Both isoforms were detected in DC and granulocytes, but not in T, B, or NK cells, or monocytes. DC-ASGPR species were restricted to the CD14-derived DC obtained from CD34(+) progenitors, while absent from the CD1a-derived subset. Accordingly, both monocyte-derived DC and tonsillar interstitial-type DC expressed DC-ASGPR protein, while Langerhans-type cells did not. Furthermore, DC-ASGPR is a feature of immaturity, as expression was lost upon CD40 activation. In agreement with the presence of tyrosine-based and dileucine motifs in the intracytoplasmic domain, mAb against DC-ASGPR was rapidly internalized by DC at 37 degrees C. Finally, intracellular DC-ASGPR was localized to early endosomes, suggesting that the receptor recycles to the cell surface following internalization of ligand. Our findings identify DC-ASGPR/human macrophage lectin as a feature of immature DC, and as another lectin important for the specialized Ag-capture function of DC.

Amino Acid Sequence↗
PubMed2001

The major synovial targets of the rheumatoid arthritis-specific antifilaggrin autoantibodies are deiminated forms of the alpha- and beta-chains of fibrin.

IgG antifilaggrin autoantibodies (AFA) are the most specific serological markers of rheumatoid arthritis. In epithelial tissues, they recognize citrulline-bearing epitopes present on various molecular forms of (pro)filaggrin. Histological analysis of rheumatoid synovial membranes with an Ab to citrulline showed labeling of interstitial amorphous deposits and mononuclear cells of various types. Immunochemical analysis of exhaustive sequential extracts of the same tissues showed that they contain several deiminated (citrulline containing) proteins. Among them, two proteins, p64--78 and p55--61, present in urea-DTT and guanidine extracts, were shown by immunoblotting to be specifically targeted by AFA. By amino-terminal sequencing the proteins were identified as deiminated forms of the alpha- and beta-chains of fibrin, respectively. Their identity was confirmed using several Abs specific for the A alpha- and/or to the B beta-chain of fibrin(ogen). Moreover, AFA-positive rheumatoid arthritis (RA) sera and purified AFA were highly reactive to the A alpha- and B beta-chains of human fibrinogen only after deimination of the molecules by a peptidylarginine deiminase. Autoantibodies affinity purified from a pool of RA sera onto deiminated fibrinogen were reactive toward all of the epithelial and synovial targets of AFA. This confirmed that the autoantibodies to the deiminated A alpha-and B beta-chains of fibrinogen, the autoantibodies to the synovial proteins p64--78 and p55--61, and, lastly, AFA, constitute largely overlapping autoantibody populations. These results show that deiminated forms of fibrin deposited in the rheumatoid synovial membranes are the major target of AFA. They suggest that autoimmunization against deiminated fibrin is a critical step in RA pathogenesis.

Animals↗
PubMed2001

Adverse events in British hospitals: preliminary retrospective record review.

OBJECTIVES: To examine the feasibility of detecting adverse events through record review in British hospitals and to make preliminary estimates of the incidence and costs of adverse events. DESIGN: Retrospective review of 1014 medical and nursing records. SETTING: Two acute hospitals in Greater London area. MAIN OUTCOME MEASURE: Number of adverse events. RESULTS: 110 (10.8%) patients experienced an adverse event, with an overall rate of adverse events of 11.7% when multiple adverse events were included. About half of these events were judged preventable with ordinary standards of care. A third of adverse events led to moderate or greater disability or death. CONCLUSIONS: These results suggest that adverse events are a serious source of harm to patients and a large drain on NHS resources. Some are major events; others are frequent, minor events that go unnoticed in routine clinical care but together have massive economic consequences.

Costs and Cost Analysis↗
PubMed2001

Principles of risk and safety.

Studies of error and adverse events in medicine have brought a growing awareness of the extent of harm to patients. The psychology of human error strongly suggests that individual liability to error is strongly influenced by the conditions and organisation of the working environment and the nature of the task, in particular the complex and inherently uncertain judgements frequently made in medicine. Research into accidents in medicine and other high risk areas has lead to a much broader concept of causation, with less focus on individuals and more on pre-existing organisational factors. These ideas have been adapted to practical use in healthcare in the analysis of adverse events and in working towards developing safer systems of care. The final section of the paper summarises the implications of this approach for healthcare in terms of an overall systems approach, the need for basic information about clinical incidents, the benefits of systematic investigation and analysis, the nature of safety interventions, the need to study success as well as failure and the need to develop an open, safety aware culture in healthcare.

Forecasting↗
PubMed2001

Efficacy of essential oil of Ocimum basilicum L. and O. gratissimum L. applied as an insecticidal fumigant and powder to control Callosobruchus maculatus (Fab.)

Essential oils from sweet basil, Ocimum basilicum, and African basil, O. gratissimum, (Labiatae) grown in Guinea were obtained by steam distillation. Following exposure of newly emerged adult beetles (Callosobruchus maculatus) to 12h of fumigation using pure essential oils at a dose of 25&mgr;l/vial, 80% mortality was recorded for O. basilicum, 70% for O. gratissimum and 0% in the control. A significant difference was observed between the responses of males and females with males exhibiting greater sensitivity. When 1g of aromatized powder was applied to adults, a 50% lethal concentration at 48h was found to be 65&mgr;l/g for O. basilicum and 116&mgr;l/g of O. gratissimum oils. The essential oils from the two plant species exhibited a significant effect both on the egg hatch rate and on the emergence of adults. The egg hatch rate was reduced to 3% with O. basilicum and 15% with O. gratissimum using an essential oil concentration of 30&mgr;l, whereas the egg hatch rate for the control was 95%. When compared with the control (97%), adult emergence dropped to 0% with O. basilicum and to 4% with O. gratissimum. Storage bioassays were run to assess the long-term effect of powders aromatized with essential oils of Ocimum. Complete protection was observed over 3 months starting at a dose of 400&mgr;l in the case of both oils. From a germination test, it was concluded that aromatized powders have no significant effect on the seed germination rate. After 5d, a rate of 88% germination was seen in seeds treated with aromatized powder and protected from insects, compared with 97% for untreated seeds that were not exposed to insects.

Journal Article↗
PubMed2001

[Bacterial epidemiological study of acute otitis media in children observed at home in the Nord Pas-de-Calais region].

BACKGROUND: The aim of this work is the study of the bacteriologic epidemiology of acute otitis media in infants observed at home in Nord Pas-de-Calais area, and the analysis of bacteria associated to recurrent otitis and clinical failure. OBSERVATIONS: A total of 295 specimens of ear pus specimens were collected from children (mean age: 18 months; average: one month-12 years). Pneumococcus strains were isolated from 52% of samples and 80% of these showed resistance to penicillin. H. influenzae was found in 35% of specimens and the half produced a beta lactamase. Pneumococcus is the predominant pathogen isolated in prolonged otitis media, while H. influenzae is preferentially found during recurrent otitis media. The main bacteriologic cause of failure traitement was penicillin-intermediate or -resistant pneumococci. The therapy administered 48 to 72 hours before collection of ear pus sample in therapeutic failure was ineffective (oral cephalosporins or macrolides), or administered to low dosage (50 mg/kg/j). CONCLUSION: Our results demonstrate, in opposition to other studies, Streptococcus pneumoniae as the most frequent pathogen in acute otitis media. They also show the excellent correlation between antibiotic therapy and clinical failures.

Bacterial Infections↗
PubMed2001

Identification of six novel polymorphisms in the human corneodesmosin gene.

Psoriatic epidermis is characterised by a defective differentiation program leading to an abnormal permeability barrier and impaired desquamation. The corneodesmosin gene (CDSN) or "S" gene is a strong candidate in psoriasis susceptibility, due first to its genomic position ("S" gene, 160 kb telomeric to HLA-C) and second to its expression and function in the epidermis. Moreover, an association between CDSN and psoriasis vulgaris was recently shown in Caucasian populations. In order to pursue the CDSN polymorphism analysis, we determined the sequence of its alleles in 14 HLA-Cw6-positive individuals. A 4.6 kb genomic fragment encompassing the first exon, the unique intron and the coding sequence of the second exon was amplified from 8 psoriatic patients and 6 controls. Allelic discrimination was performed by restriction fragment length polymorphism analysis. The entire coding sequence and the intron boundaries of 27 alleles were sequenced. A total of 26 dimorphic sites were found, 23 consisting in single nucleotide polymorphisms (SNPs) and 3 in triplet modifications. Five out of the 23 SNPs have not been previously reported, and among them, one causes amino-acid exchange leading to the suppression of a potential chymotrypsin site. Among the triplet modifications, one leads to deletion of one out of five consecutive valines in the protein. The high polymorphism of the gene allowed the identification of 13 different alleles. These haplotypes will permit additional family-based studies that could provide new genetic support for the involvement of CDSN in psoriasis susceptibility. Moreover, the establishment of an extensive catalogue of CDSN alleles will allow functional analyses of the different protein isoforms.

Alleles↗
PubMed2001

Body size as an indicator of parasitoid quality in male and female Anagyrus kamali (Hymenoptera: Encyrtidae).

The parasitoid Anagyrus kamali Moursi was recently introduced into the Caribbean as a biological control agent against the hibiscus mealybug, Maconellicoccus hirsutus Green. In the laboratory, parasitoid size, as measured by left hind tibia length, was positively correlated with several indicators of the parasitoid's fitness: longevity, mating preference, fecundity, reproductive longevity, progeny emergence and sex-ratio. When fed ad libidum with honey drops, large male parasitoids lived significantly longer (29.1 +/- 6.5 days) than small ones (18.4 +/- 5.7 days). Large females also lived significantly longer (35.4 +/- 10 days) than small females (27.9 +/- 9.6 days). Females showed no significant mating preference between large and small males. Lifetime fecundity was positively correlated with the size of adult females and ranged from 37 +/- 21 eggs for small females to 96 +/- 43 eggs for large ones. The reproductive longevity, daily oviposition rate, and number of progeny were also higher among large parasitoids. The sex ratio of progeny from small female parasitoids was higher (0.76 +/- 0.24) than that of large individuals (0.47 +/- 0.18).

Animals↗
PubMed2001

Antifilaggrin antibodies in early rheumatoid arthritis may predict radiological progression.

OBJECTIVE: To elucidate the possibility that autoantibodies to filaggrin, detected in patients with early RA (having a disease duration of not more than one year), may predict joint destruction assessed after five years of observation. METHODS: This is a 5 yr extension of a previous study (1) of 112 consecutive patients with early RA. Serum antifilaggrin autoantibodies were detected by immunoblotting (AFA) and by indirect immunofluorescence ("AKA"). DAS28, pain on a VAS. HAQ, and CRP were measured. Plain X-ray films were taken from hands and forefeet and a Larsen score was calculated. RESULTS: Ninety-two of the original 112 patients had baseline X-rays available and constituted the study material. At 5 year follow-up, 67 of these 92 have been assessed and for 63 of these X-rays were available. For the whole patient material, significant radiological progression, measured by Larsen scores, occurred while disease activity and function (pain VAS, DAS28, CRP, and HAQ) improved significantly over five years. The groups of patients having AFA or "AKA" at baseline had significantly (p=0.006 and p<0.001, respectively) higher Larsen scores five years later than the groups without these antibodies. No clear relation of these antibodies to disease activity or function was demonstrated, except that the group of patients with "AKA" had significantly higher median CRP (p=0,003) after five years. CONCLUSIONS: The present study shows that antifilaggrin autoantibodies may predict radiological progression. The prognostic value of these antibodies will be further evaluated in relation to other potential markers in a larger patient material.

Arthritis, Rheumatoid↗
PubMed2001

Clinical results of an investigation of paediatric upper limb myoelectric prosthesis fitting at the Quebec Rehabilitation Institute.

This study was designed to investigate the satisfaction level of young users of myoelectric prostheses who received an upper limb myoelectric prosthesis, to assess their dropout rate and to identify which factors influence the use or non-use of the upper limb myoelectric prosthesis in the eastern part of Quebec (Canada). The users were fitted between 1990 and 1999 at the Quebec Rehabilitation Institute, a major rehabilitation centre located in the province of Quebec. This rehabilitation centre provides cutting-edge expertise not only for the eastern part of Quebec, but also across the entire province, because it is one of only two highly specialised centres serving all of Quebec. A literature review was completed to compile the results obtained in other rehabilitation centres and to identify factors influencing the use or non-use of paediatric upper limb myoelectric prostheses. The Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) was used in order to assess the degree to which the children were satisfied with their prostheses. Eighteen (18) children were fitted and trained to use an upper limb myoelectric prosthesis. A total of 10 children and parents agreed to participate. Some 80% of participants said that they were satisfied with their prostheses. A dropout rate of 53% for the overall group (participants and non-participants) seems high compared with that of other studies. Recommendations linked to factors identified in the literature are made. The authors conclude that a multidisciplinary team and structured training and follow-up can improve the clinical results pertaining to all the factors proposed in the literature.

Adolescent↗
PubMed2001

A multicenter study of the Vibrant Soundbridge middle ear implant: early clinical results and experience.

OBJECTIVE: The Vibrant Soundbridge (VBS; Symphonix Devices, Inc., San Jose, CA, U.S.A.) is an active, semi-implantable, middle ear hearing device that directly drives the ossicular chain and is used in the treatment of patients with mild to severe sensorineural hearing loss. The benefits of the VBS and the effects of surgery were examined and compared with the preoperative aided condition in 25 patients with implants. STUDY DESIGN: Single-subject repeated-measures evaluations were performed with each patient acting as his or her own control. Objective audiologic measures and subjective questionnaires also were used. SETTING: Five tertiary referral and teaching hospitals. SUBJECTS: Adult patients had bilateral sensorineural hearing loss (average hearing loss, 56 dB; range, 33-80 dB). Twenty-one patients had worn a conventional hearing aid before surgery (11 binaurally, 10 monaurally). Four patients had not used a conventional hearing aid before surgery. INTERVENTION: Rehabilitative. RESULTS: No significant change in residual hearing after surgery was observed. Functional gain was significantly superior with the VBS. No significant differences were observed for aided speech recognition in quiet. A significant improvement in communication in various listening conditions was reported with the VBS as compared with conventional hearing aids. CONCLUSION: The VBS surgical implantation procedure does not affect the residual hearing level in the implanted ear, nor does it present any unacceptable risk. Measurable benefit from the VBS in comparison with conventional amplification was demonstrated with regard to the provision of superior usable amplification and greater ease in communication in daily listening environments for the majority of patients.

Acoustic Stimulation↗
PubMed2001

Risks of elective cardiac surgery: what do patients want to know?

OBJECTIVE: To examine patients' individual requirements for risk disclosure before surgery. DESIGN: Structured interview and questionnaire. SETTING: 50 patients interviewed following coronary artery bypass grafting or valve replacement or repair. MAIN OUTCOME MEASURES: Patient assessment of the nature and probability of risks they would have wished to be informed of from a pool comprising death and 13 postoperative complications. RESULTS: Out of 50 patients, 21 (42%) wanted no risk information at all, 25 (50%) did not want to be advised of the risk of death, and 27 (54%) did not want information about the risk of permanent stroke. This contrasts with standard practice of routinely informing patients of the risk of death and stroke. However, there were pronounced individual patient preferences. Three groups of patients emerged: those requiring little or no risk information, those requiring information about major risks, and those requiring full risk disclosure. Patients were not generally concerned about the specific probabilities of any risk. CONCLUSIONS: Clinicians counselling patients before operation should routinely discuss patient preferences before risk disclosure, distinguishing among a preference for "no risk information", "all potentially relevant risks", and "those risks considered significant or likely to occur". The fact of individual patient preferences may undermine the concept of the "reasonable patient" in determination of the legal requirements for risk disclosure. Future studies, in addition to replicating the present findings, should examine the reasons underlying individual patient preferences and the long term implications of degrees of risk disclosure, particularly when adverse outcomes occur.

Adult↗
PubMed2001

Exploring the causes of adverse events in NHS hospital practice.

In a previous paper we reported that 10.8% of patients admitted to two large hospitals in Greater London experienced one or more adverse events, of which half were deemed preventable. Here we examine the underlying causes of errors in clinical practice. Rather than identifying specific errors made by individuals, we have looked at possible faults in the organization of care. Adverse events were grouped according to stages in the care process: diagnosis, preoperative assessment and care, operative or invasive procedure (including anaesthesia), ward management, use of drugs and intravenous fluids and discharge from hospital. Less than 20% of preventable adverse events were directly related to surgical operations or invasive procedures and less than 10% to misdiagnoses. 53% of preventable adverse events occurred in general ward care (including initial assessment and the use of drugs and intravenous fluids) and 18% in care at the time of discharge. Probable contributory factors in these errors included dependence on diagnoses made by inexperienced clinicians, poor records, poor communication between professional carers, inadequate input by consultants into day-to-day care, and lack of detailed assessment of patients before discharge.

Aged↗
PubMed2001

The cephalic neural crest provides pericytes and smooth muscle cells to all blood vessels of the face and forebrain.

Most connective tissues in the head develop from neural crest cells (NCCs), an embryonic cell population present only in vertebrates. We show that NCC-derived pericytes and smooth muscle cells are distributed in a sharply circumscribed sector of the vasculature of the avian embryo. As NCCs detach from the neural folds that correspond to the future posterior diencephalon, mesencephalon and rhombencephalon, they migrate between the ectoderm and the neuroepithelium into the anterior/ventral head, encountering mesoderm-derived endothelial precursors. Together, these two cell populations build a vascular tree rooted at the departure of the aorta from the heart and ramified into the capillary plexi that irrigate the forebrain meninges, retinal choroids and all facial structures, before returning to the heart. NCCs ensheath each aortic arch-derived vessel, providing every component except the endothelial cells. Within the meninges, capillaries with pericytes of diencephalic and mesencephalic neural fold origin supply the forebrain, while capillaries with pericytes of mesodermal origin supply the rest of the central nervous system, in a mutually exclusive manner. The two types of head vasculature contact at a few defined points, including the anastomotic vessels of the circle of Willis, immediately ventral to the forebrain/midbrain boundary. Over the course of evolution, the vertebrate subphylum may have exploited the exceptionally broad range of developmental potentialities and the plasticity of NCCs in head remodelling that resulted in the growth of the forebrain.

Animals↗
PubMed2001

Acaricidal properties of Artemisia absinthium and Tanacetum vulgare (Asteraceae) essential oils obtained by three methods of extraction.

Essential oils of Artemisia absinthium L. and Tanacetum vulgare L. were extracted by three methods, a microwave assisted process (MAP), distillation in water (DW) and direct steam distillation (DSD), and tested for their relative toxicity as contact acaricides to the two spotted spider mite, Tetranychus urticae Koch. All three extracts of A. absinthium and of T. vulgare were lethal to the spider mite but to variable degrees. The LC50 obtained from the DSD oil of A. absinthium was significantly lower (0.04 mg/cm2) than that of the MAP (0.13 mg/cm2) and DW (0.13 mg/cm2) oil of this plant species. DSD and DW extracts of T. vulgare were more toxic (75.6 and 60.4% mite mortality, respectively, at 4% concentration) to the spider mite than the MAP extract (16.7% mite mortality at 4% concentration). Chromatographic analysis indicated differences in composition between the more toxic DSD oil of A. absinthium and the other two extracts of this plant, indicating that a sesquiterpene (C15H24) compound present in the DSD oil and absent in the other two may enhance the toxicity of the DSD oil. Chemical analysis of the T. vulgare extracts indicated that beta-thujone is by far the major compound of the oil (>87.6%) and probably contributes significantly to the acaricidal activity of the oil.

Animals↗