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Biomedical subjects

C Vincent

Publications and source records attributed to C Vincent.

At least 19 recordsLinked to original sources
PubMed2006

Toxoplasma gondii: comparison of human CD34+ and monocyte-derived dendritic cells after parasite infection.

Human dendritic cells (DC) obtained in vitro from CD34(+) progenitors (CD34-DC) or blood monocytes (mo-DC) are different DC which may be used in a model of T. gondii infection. We compared the survival, infection rate and cell surface receptor expression of both DC types after living T. gondii tachyzoite infection. CD34-DC appeared less resistant to the parasite than mo-DC. At 48h post-infection, chemokine receptors responsible for DC homing and migration were absent in mo-DC, while down regulation of CCR6 and up regulation of CCR7 was observed in CD34-DC. This result, suggesting migration ability of CD34-DC, was confirmed by in vitro migration experiments against different chemokines. Tachyzoite supernatant, used as chemokine, attracted immature CD34-DC as observed by MIP3alpha, while MIP3beta, as expected, attracted mature CD34-DC. Under similar conditions, no significant difference was noticed between mature or immature mo-DC. These data indicated that CD34-DC represent an alternative model that allows migration assay of infected DC by T. gondii.

Animals↗
PubMed2006

Effect of selected insecticides on growth rate and stress protein expression in cultured human A549 and SH-SY5Y cells.

Two organochlorines (dienochlor, endosulfan) and one neonicotinoid (imidacloprid) insecticides were investigated as putative cellular aggressors, both as pure chemicals and as commercial formulations, in order to evaluate the additional toxicity due to additives present in the commercial formulations. Toxicity was evaluated on human cells in vitro, by culturing neuronal SH-SY5Y and pulmonary A549 cell lines for 3 days in the presence of increasing concentrations of the selected pesticides. LOEC (lowest observed effect concentration), IC50 (concentration leading to a 50% decrease of cell growth) and expression changes of molecular chaperones involved in cellular protein quality control were determined. The investigated molecular chaperones were the cytosolic resident heat shock proteins (HSP27, HSP72/73, and HSP90) and the glucose regulated proteins (GRP78, GRP94) located in the endoplasmic reticulum (ER). Organochlorines were found to be the most toxic in both A549 and SH-SY5Y cells, IC50 being respectively 0.95 and 0.36 microM for dienochlor, 34 and 20 microM for endosulfan, 1.8 and 1.5 mM for imidacloprid. This shows that neuronal cells were more sensitive than pulmonary cells. LOEC and IC50 appeared at lower concentrations of active molecule when using the commercial formulations Techn'ufan (endosulfan) and Confidor (imidacloprid), indicating an additional adverse effect of additives. Insecticide concentrations higher than IC50 were found to induce an underexpression of all cytosolic HSPs, probably resulting from a general inhibition of protein synthesis. HSP27 was found to be underexpressed at concentrations of imidacloprid or endosulfan (as Techn'ufan) lower than IC50. This underexpression of the anti-apoptotic HSP27 could contribute to the increase of cell mortality. GRP78 was up-regulated by endosulfan in A549, but not in SH-SY5Y cells, suggesting a damaging effect on proteins specific to pulmonary cells. Conversely, HSP72/73 was found to be down-regulated, resulting probably from the ER unfolded protein response (UPR) as previously reported [Skandrani, D., Gaubin, Y., Vincent, C., Beau, B., Murat, J.C., Soleilhavoup, J.P., Croute, F., 2006. Relationship between toxicity of selected insecticides and expression of stress protein (HSP, GRP) in cultured human cells: effects of commercial formulations versus pure active molecules. Biochim. Biophys. Acta 1760 (1), 95-103].

Adenocarcinoma↗
PubMed2006

Self-appraisal hierarchical task analysis of laparoscopic surgery performed by expert surgeons.

BACKGROUND: Evaluation of technical skill is notoriously difficult because of the subjectivity and time-consuming expert analysis. No ongoing evaluation scheme exists to assess the continuing competency of surgeons. This study examined whether surgeons' self-assessment accurately reflects their actual surgical technique. METHODS: Hierarchical task analysis (HTA) of laparoscopic cholecystectomy was constructed. Ten expert surgeons were asked to modify the HTA for their own technique. The HTAs of these surgeons then were compared with their actual operations, which had been recorded and assessed by two observers. RESULTS: A total of 40 operations were assessed. All the gallbladders subjected to surgery were classified as grades 1 to 3. The mean interrater reliability for the two observers had a k value of 0.84 (p < 0.05), and the mean intrarater reliability between surgeons and observers had a k value of 0.79 (p < 0.05). CONCLUSIONS: Surgeons' self-evaluation is accurate for technical skills aspects of their operations. This study demonstrates that self-appraisal using HTA is feasible, accurate, and practical. The authors aim to increase the numbers in their study and also to recruit residents.

Adult↗
PubMed2006

The dental health and preventative habits of cardiac patients attending the Royal Hospital for Sick Children Glasgow.

AIM: To assess the dental health and preventive practices of child patients with congenital heart disease treated at the Royal Hospital for Sick Children, Glasgow. STUDY DESIGN: A retrospective study using an audit data collection sheet. METHODS: Data collected for 370 paediatric cardiac patients between January 2002 and December 2003 was analysed to obtain an insight into these patients' tooth brushing methods, use of fluoride (F), dental attendance and past dental treatment. An oral examination assessed the patient's caries experience. RESULTS: There were 195 subjects aged between 1 and 5 years, 105 were 6 - 11 years and 70 were 12 -16 years of whom 291 (78%) children were registered for dental care. Of these children 331 (90%) maintained that they brushed their teeth regularly with F- toothpaste. Experience of dental treatment revealed that 132 (36%) children had undergone previous dental treatment. Oral examination showed that out of 370 patients, 236 (64%) had no active caries. The dental health of the cardiac subjects was poor compared with that of Scottish primary school children (5 year-olds) and the 12 year-olds but compared favourably with the 14-year old group. STATISTICS: The relationship between caries activity and frequency of toothbrushing was significant (p<0.01). The relationship between caries activity and attendance for dental care was not significant. CONCLUSION: Children with cardiac problems should be identified in early infancy through liaison with medical colleagues and the family offered all the preventive advice and regular dental care necessary to prevent dental disease.

Adolescent↗
PubMed2006

Violations and migrations in health care: a framework for understanding and management.

Violations are deliberate deviations from standard procedure. The usual reaction is to attempt to eliminate them and reprimand those concerned. However, the situation is not that simple. Firstly, violations paradoxically may be markers of high levels of safety because they need constraints and defences to exist. They may even become more frequent than errors in ultrasafe systems. Secondly, violations have both positive and negative aspects. On the one hand they occur frequently, increase system performance and individual satisfaction, are mostly limited to practices with limited safety consequences, and therefore are often tolerated or even encouraged by the hierarchy. On the other hand, extreme violations can lead to real danger or actual harm. This paper proposes a three phase model derived from Rasmussen's theory of migration to boundaries to explain the mechanism by which the deviance occurs, stabilizes, regresses, or progresses to harm. The model suggests that violations are unavoidable because system dynamics and deviances are markers of adaptation to this dynamicity. Violations cannot be eliminated but they can be managed. Solutions are specific to each step of the model, with a mix of relaxing constraints, increasing peer control (staff), and constraining dangerous individuals.

Attitude of Health Personnel↗
PubMed2006

Changes in growth rate and thyroid- and sex-hormones blood levels in rats under sub-chronic lithium treatment.

Lithium therapy, mainly used in curing some psychiatric diseases, is responsible for numerous undesirable side effects. The present study is a contribution to the understanding of the pathophysiological mechanisms underlying lithium toxicity. Male and female mature rats were divided into three batches and fed commercial pellets: one batch was the control and the second and third batches were given 2 g (Li1) and 4 g (Li2) of lithium carbonate/kg of food/day, respectively. After 7, 14, 21 and 28 days, serum levels of free tri-iodothyronine (FT3), thyroxine (FT4), testosterone and estradiol were measured. Attention was also paid to growth rate and a histological examination of testes or vaginal mucosa was carried out. In treated rats, a dose-dependent loss of appetite and a decrease in growth rate were observed, together with symptoms of polydypsia, polyuria and diarrhea. Lithium serum concentrations increased from 0.44 mM (day 7) to 1.34 mM (day 28) in Li1 rats and from 0.66 to 1.45 mM (day 14) in Li2 rats. Li2 treatment induced a high mortality after 14 days, reaching 50-60% in female and male animals. From these data, the LD50 (14 days Li2 chronic treatment) was calculated to be about 0.3 g/day per kilogram of animal, leading to Li serum concentrations of about 1.4 mM. A significant decrease of FT3 and FT4 was observed in treated rats. This effect appeared immediately for the highest dose and was more pronounced for FT3, resulting in an increase of the FT4/FT3 ratio. In males, testosterone decreased and spermatogenesis was stopped. Conversely, in females, estradiol increased in a dose-dependent manner as the animals were blocked in the diestrus phase at day 28. This finding supports a possible antagonistic effect of lithium on the estradiol receptors.

Animals↗
PubMed2005

Technical skills errors in laparoscopic cholecystectomy by expert surgeons.

BACKGROUND: Performing laparoscopic surgery involves a complex cascade of cognitive skills, which may inherently have a constant technical error rate. We assess generic and specific minor and major error rates in laparoscopic cholecystectomies (LCs) performed by consultant surgeons. METHODS: Checklists of generic (11) and specific technical minor (six) and major events (eight) were devised for LCs. Two experienced surgeons assessed each full-length operation blindly and independently. RESULTS: A total of 37 LCs were performed by eight consultants. There were no major intraoperative or postoperative complications. Mean inter-rater reliability was kappa = 0.91 (range 0.80-0.98) for each of the error categories. Error rates were generic (27/407) 6.6%, minor (59/222) 26.6%, and major (8/296) 2.7%, respectively. There was a significant statistical difference between the minor error group and the other groups, p <or= 0.05. CONCLUSIONS: Performing laparoscopic surgery may always have a background technical error rate. Our present study demonstrates a migration of surgical technical errors in expert laparoscopic surgeons. The surgeons migrate technically when they execute a high rate of procedure-specific minor errors. However, when it comes to the major fundamental aspects of the operation, they dynamically adapt and migrate away from performing major technical errors. We aim to continue the study to increase cases, assess trainees as well, and also explore other factors that may affect the surgeon when executing surgical technical tasks.

Adult↗
PubMed2005

Effect of kaolin on fitness and behavior of Choristoneura rosaceana (Lepidoptera: Tortricidae) larvae.

The mechanisms by which kaolin, a clay particle film formulation, affects the fitness and behavior of larvae of obliquebanded leafroller, Choristoneura rosaceana (Harris), were investigated. Feeding experiments tested kaolin as a physical barrier versus a physiological toxin for larvae that consumed kaolin applied either to apple (Malus spp.) leaves or mixed in artificial diet. Behavioral experiments tested the effects of kaolin applied to apple leaves on neonate dispersal and leaf rolling by third and fourth instars. When larvae fed on apple leaves sprayed with kaolin, mortality and time to pupation of larvae increased significantly, whereas pupal mass significantly decreased. When larvae consumed kaolin mixed into an artificial diet, however, the effects on mortality, pupation time, and pupal mass were negligible. There may be minor physiological effects from consumption because male time to pupation was delayed for larvae fed diets containing the highest concentration of kaolin. In behavioral experiments, neonate larvae dispersed more quickly off plants covered with kaolin than control plants, and kaolin delayed the construction of leaf shelters by third and fourth instars. We showed that the effects of kaolin on C. rosaceana larvae are primarily physical, causing changes in dispersal and rolling behaviors and as a physical barrier to feeding.

Animals↗
PubMed2005

IgG subclass distribution of the rheumatoid arthritis-specific autoantibodies to citrullinated fibrin.

In the rheumatoid synovium, deiminated ('citrullinated') forms of fibrin are the major targets of IgG autoantibodies to citrullinated proteins (ACPA), the most specific serological markers of rheumatoid arthritis (RA). To further the characterization of ACPA, we determined their subclass distribution. From a previously validated highly sensitive and specific enzyme-linked immunosorbent assay (ELISA) onto in vitro deiminated human fibrinogen - antihuman fibrin(ogen) autoantibodies (AhFibA)-ELISA - we derived and calibrated four ELISAs, using monoclonal antibodies to each of the four IgG subclasses, to determine the proportions of AhFibA subclasses in the sera. A series of 186 serum samples from RA patients was analysed. All AhFibA-positive sera contained IgG1-AhFibA, which reached the highest titres and accounted for more than 80% of AhFibA in three-quarters of the sera. One or two other subclasses were associated with IgG1 in 39% of the sera, IgG4-AhFibA being observed much more frequently and at higher titres than IgG3- or IgG2-AhFibA. IgG1 alone or IgG(1 + 4)-AhFibA were the AhFibA subclass profiles found in more than 80% of patients. AhFibA are mainly IgG1 and, to a lesser extent, IgG4. Such IgG subclass profiles may influence the effector phases of the immunological conflict between ACPA and deiminated fibrin that takes place specifically in the rheumatoid synovium and therefore may play a critical role in the self-maintenance of rheumatoid inflammation.

Adolescent↗
PubMed2005

Toxoplasma gondii regulates recruitment and migration of human dendritic cells via different soluble secreted factors.

We investigated in vitro the properties of soluble factors produced by Toxoplasma gondii on the recruitment, maturation and migration of human dendritic cells (DC) derived from CD34+ progenitor cells. We used soluble factors including excreted secreted antigens (ESA) produced under various conditions by the virulent type I RH strain (ESA-RH) and the less virulent PRU type II strain (ESA-PRU). Soluble factors of both T. gondii strains appeared to possess a chemokine-like activity that attracted immature DC. This recruitment activity required the presence of functional CCR5 molecules on the cell membrane. Incubation of DC for 24 h with ESA triggered the migration of a large percentage of these cells towards the chemokine MIP-3beta; ESA-PRU was more efficient than ESA-RH. ESA produced in absence of exogenous protein and crude extract did not induce DC migration but retained recruitment activity. These data indicate that recruitment activity and migration-inducing activity are not governed by the same factors. Moreover, incubation of DC for 48 h with ESA did not modify the expression of costimulation or maturation markers (CD83, CD40, CD80, CD86 or HLA-DR), but induced a decrease in CCR6 expression associated with an increased expression of CCR7. Taken together, these results suggest that T. gondii controls recruitment and migration of immature DC by different soluble factors and may induce a dysfunction in the host-specific immune response.

Animals↗
PubMed2005

The investigation and analysis of critical incidents and adverse events in healthcare.

OBJECTIVES: To carry out a review of published and unpublished work on the analysis on methods of accident investigation in high-risk industries, and of critical incidents in healthcare. To develop and pilot guidelines for the analysis of critical incidents in healthcare for the hospital sector, mental health and primary care. DATA SOURCES: Literature already available in the Clinical Risk Unit, University College London. Work by known experts in the field of accident investigation and analysis. Electronic databases including PsycINFO and MEDLINE. Websites for accident investigation reports. REVIEW METHODS: Twelve techniques from other high-risk industries were reviewed in detail using criteria developed for the purpose. This review provided a conceptual framework for the healthcare review and appraisal process, as well as providing a critical assessment of the industry techniques. Rigorous searching and screening identified 138 papers for formal appraisal and a further 114 were designated as providing potentially useful background information. A formal appraisal instrument was designed, piloted and modified until acceptable reliability was achieved. From the 138 papers, six techniques were identified as representing clearly definable approaches to incident investigation and analysis. All relevant papers were reviewed for each of the six techniques: Australian Incident Monitoring System, the Critical Incident Technique, Significant Event Auditing, Root Cause Analysis, Organisational Accident Causation Model and Comparison with Standards approach. RESULTS: All healthcare techniques had the potential of being applied in any specialty or discipline related to healthcare. While a few studies looked solely at death as an outcome, most used a variety of outcomes including near misses. Most techniques used interviewing and primary document review to investigate incidents. All techniques included papers that identified clinical issues and some attempt to assess underlying errors, causes and contributory factors. However the extent and sophistication of the various attempts varied widely. Only a third of papers referred to an established model of accident causation. In most studies examined there was little or no information on the training of investigators, how the data was extracted or any information on quality assurance for data collection and analysis. There was some variation in the level of expertise and training required but to undertake the investigation to an acceptable depth all required some expertise. In most papers there was little or no discussion of implementation of any changes as a result of the investigations. A quarter of publications gave some description of the implementation of changes, though few addressed evaluation of changes. CONCLUSIONS: The reviews demonstrate that, while much valuable work has been accomplished, there is considerable potential for further development of techniques, the utilisation of a wider range of techniques and a need for validation and evaluation of existing methods which would make incident investigation more versatile and use limited resources more effectively. Further exploration of techniques used in high-risk industries, with interviews and observation of actual investigations should prove valuable. Existing healthcare techniques would benefit from formal evaluation of their outcomes and effectiveness. Studies should examine depth of investigation and analysis, adequacy and feasibility of recommendations and cost effectiveness. Examining implementation of recommendations is a key issue.

Benchmarking↗
PubMed2005

Dynamic contour tonometry (DCT) versus non-contact tonometry (NCT): a comparison study.

In a prospective study we measured the intraocular pressure (IOP) by means of a Non-Contact Tonometer (NCT) and by means of a Pascal Dynamic Contour Tonometer (DCT), and the Central Corneal Thickness (CCT) by means of a contact pachymeter in 294 emmetropic or ametropic eyes. There is a linear relation between NCT and CCT. This linear relation doesn't exist between DCT and CCT. The same measurements were done before and 6 weeks after a Lasik intervention in 58 myopic eyes. Lasik intervention influences NCT but doesn't influence DCT.

Cornea↗
PubMed2004

Novel protein kinase C and matrix metalloproteinase inhibitors of vegetable origin as potential modulators of Langerhans cell migration following hapten-induced sensitization.

BACKGROUND: Migration and maturation of epidermal dendritic cells, the Langerhans cells (LC), are central events in the initiation of the cutaneous immune response. LC migration from skin to draining lymph nodes is regarded as an indispensable step for the early phase of antigen-specific sensitization. Among the several agents which influence the ability of LC to migrate, previous studies have revealed that matrix metalloproteinases (MMPs) and protein kinase C (PKC) contribute to promoting LC migration. In this work, we studied the effect of two recently developed PKC and MMPs inhibitors of vegetable origin on the migration of in vitro activated LC. METHODS: The migratory capacity of epidermal and in vitro generated LC was assessed using a reconstituted basement membrane assay (Matrigel), mimicking the prerequisite passage through the dermal-epidermal basement membrane on the way to the lymph nodes. RESULTS: Contact with chemical allergens, Bandrowski's base or 2,4-dinitrobenzenesulfonic acid (DNBS), triggered migration. In the presence of PKC inhibitors, D-erythro-sphingosine and OX100, or an inhibitor of MMPs, LU105, allergen-induced migration of LC was strongly decreased. The association between OX100 and LU105 was more efficient in modulating the migration of activated LC compared to each molecule tested separately. CONCLUSIONS: These results showed that PKC and MMPs inhibitors act in synergy to inhibit the migration of activated epidermal dendritic cells in vitro. They underscore the role of PKC and MMPs inhibitors and suggest they may be of relevance for therapeutically regulating epidermal dendritic cell migration in inflammatory dermatoses.

Antigens, CD↗
PubMed2004

A longitudinal study on postoperative hearing thresholds with the Vibrant Soundbridge device.

The Vibrant Soundbridge is a semi-implantable middle ear hearing device used in the rehabilitation of adults with sensorineural hearing loss. In order to evaluate the long-term effects of the implanted part of the device, audiological data from 39 patients implanted over several implant sites across France were collected and analyzed retrospectively. The mean follow-up time was 16 months; 25 patients had a follow-up period of over 1 year. Surgery was uneventful in all cases. The present study of the 39 implanted patients with a mid- to long-term follow-up found a statistically significant modification of hearing thresholds (pre- versus postoperative) for frequencies of 0.5 and 4 kHz. However, the shift of threshold was rather limited (2.79 and 3.34 dB, respectively), and this variation was not statistically different from the evolution of the opposite non-operated ear.

Adult↗
PubMed2004

[Intraoperative auditory monitoring in acoustic neurinoma surgery].

Intraoperative auditory monitoring in acoustic neuroma surgery is used to improve residual hearing. Three techniques are available: monitoring of brainstem auditory evoked potentials, of electrocochleography or of direct eighth nerve compound action potential. The three techniques with their advantages and disadvantages are discussed. The current trend is to monitor brainstem auditory evoked potentials using digital filtering or to monitor the eighth nerve compound action potential.

Audiometry, Evoked Response↗
PubMed2004

Acaricidal properties of a Chenopodium-based botanical.

The emulsifiable concentrate UDA-245 [25% EC (vol:vol)], based on an essential oil extract from Chenopodium ambrosioides variety ambrosioides, a North American herbaceous plant, was compared with commercially available pesticides for their effectiveness to control the adult stage and egg hatch of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and the European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae). After a laboratory bioassay with adult twospotted spider mites, a 0.5% concentration of UDA-245 was more effective than 0.7% (AI) of neem oil (Neem Rose Defense). After a similar bioassay with the European red mite, a 0.5% concentration UDA-245 was as effective as 0.006% (AI) of abamectin (Avid). UDA-245 at 0.5% significantly reduced egg hatch of the twospotted spider mite, 5 and 9 d after treatment and of the European red mite 6 d after treatment. Egg hatch was significantly lower using 0.006% (AI) of abamectin, 0.7% of neem oil, and 1.0% insecticidal soap than UDA-245. Residual tests indicated that UDA-245 may be persistent in the environment only for a few hours. Only 23% mortality was noted when mites were introduced on bean leaves 1 h after treatment with a 2% concentration of UDA-245. At the recommended dose of 0.5%, UDA-245 was not considered phytotoxic for most plants tested, i.e., lettuce, roses, and tomatoes. Results suggest that a greenhouse integrated pest management program using UDA-245 could effectively and selectively control mite infestations by treating "hot spots" with negligible effect on biological control agents when treating before introduction or when natural enemies are absent.

Acari↗
PubMed2004

Insecticidal properties of a Chenopodium-based botanical.

The emulsifiable concentrate UDA-245 based on an essential oil extract from Chenopodium ambrosioides variety near ambrosioides, a North American herbaceous plant, was compared with commercially available pesticides for their effectiveness to control green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae), western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and greenhouse whitefly, Trialeurodes vaporariorium (Westwood) (Homoptera: Aleyrodidae). Side effects on the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae) also were determined. With green peach aphid, UDA-245 at 0.5% concentration was significantly more effective than the control (water) treatment in a laboratory bioassay and significantly more effective than neem oil and the control treatment and as effective as insecticidal soap in a greenhouse assay. With the western flower thrips, UDA-245 at 0.5% was significantly more effective than neem oil, insecticidal soap and the control treatment in a laboratory bioassay, whereas in a greenhouse assay, UDA-245 at 1.0% was the only treatment that maintained control of the western flower thrips 2 wk after the last treatment period. UDA-245 at 0.5% (laboratory bioassay) was significantly more effective in managing greenhouse whitefly than neem oil, endosulfan, and the control treatment and as effective as insecticidal soap. Insecticidal soap proved to be toxic to the parasitoid E. formosa (71.9% mortality), whereas UDA-245 at 0.5% was not significantly more toxic than the control (11.2 and 4.6% mortality, respectively). Our results suggest that a greenhouse integrated pest management (IPM) program using a botanical such as UDA-245 could effectively control infestations of major pests present while having a negligible effect on biological control agents.

Animals↗