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Biomedical subjects

C Mercier

Publications and source records attributed to C Mercier.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Clonidine combined with flunitrazepam before carotid endarterectomy decreases cerebrovascular CO2 reactivity].

OBJECTIVE: Assess cerebrovascular CO2 reactivity changes using transcranial Doppler sonography (TCD) after oral premedication associating clonidine (2 micrograms.kg-1) and flunitrazepam (70 micrograms.kg-1) in patients scheduled for carotid stenosis surgery. STUDY DESIGN: Prospective study, not randomized, the patient being his own "control". PATIENTS AND METHODS: Thirteen patients undergoing carotid endarterectomy under cervical plexus block were included. The monitoring included: automated arterial pressure cuff, ECG, radial artery catheter, TCD with probe secured in temporal window. The study of the cerebrovascular CO2 reactivity was performed with TCD recording on the side of operation, on the day before, and on the day of carotid endarterectomy, 90 min after the premedication, immediately before surgery. To change PaCO2, four ventilatory states were successively performed: (1) normoventilation, (2) hyperventilation, (3) hypoventilation, (4) "breath-holding test". At each state, it was noted: HR, MAP, PaCO2, mean blood flow velocity in the middle cerebral artery (Vm-MCA), resistance index of Pourcelot (RI), cerebrovascular reactivity (slope Vm-MCA/PaCO2). The results (+/- SEM) were analyzed by Wilcoxon test or t test. RESULTS: After premedication, cerebrovascular CO2 reactivity decreased (0.043 +/- 0.019 vs 0.034 +/- 0.013; p < 0.05) without modification of RI (0.578 +/- 0.291 vs 0.612 +/- 0.025; NS). No complication during carotid clamping was reported. CONCLUSION: Inclusion of clonidine in premedication before carotid stenosis surgery must be questioned because a decrease of cerebrovascular CO2 reactivity could be deleterious in case of intraoperative stroke.

Adrenergic alpha-Agonists↗
PubMed2001

Perceived and valued roles of adults with severe mental health problems.

The purpose of this article is to convey the findings of two studies related to the perception of past, present and future roles, the value attributed to these roles as well as the role patterns. Both studies were conducted with adults who have schizophrenia and are involved in a rehabilitation or work program. Data were collected from two sources: 1) secondary analysis of a study related to the methodology for validating the French translation (Hachey, Jumoorty, & Mercier, 1995) of the "Role Checklist", (Barris, Oakley, & Kielhofner, 1988) and 2) a research project on the perception of roles and quality of life. Results showed that the dominant roles assumed by participants regardless of time were family member, friend, home maintainer and hobbyist. The most valued roles were those of friend, worker, and family member. The discussion will address the questions asked and elucidate the role patterns. The conclusion underlines the importance, for occupational therapists and health professionals, of including roles in the daily lives of their clients, taking into consideration the ones they value most highly.

Activities of Daily Living↗
PubMed2001

Tumorigenicity of the mixed spindle-epithelioid SP6.5 and epithelioid TP17 uveal melanoma cell lines is differentially related to alpha5beta1 integrin expression.

PURPOSE: It has been suggested that the epithelioid morphology and high aggressiveness that is typical of the uveal melanoma cell line TP17 is dependent on the loss of alpha5beta1 integrin expression at the cell surface. The purpose of the current study was to test this hypothesis in the TP17 cell line and investigate the role this integrin may play in the tumorigenicity of the SP6.5 cells, a mixed spindle-epithelioid culture-type human uveal melanoma that shows tumorigenic properties clearly distinct from that of TP17 cells. METHODS: Expression of the alpha5 integrin subunit was restored in the alpha5-TP17 cell line by stably transfecting the cells with a recombinant plasmid encoding the integrin subunit. Flow cytometry and adhesion assays on fibronectin (FN)-coated culture plates were used to monitor alpha5 expression in the cells. The effect of alpha5 expression on both tumorigenicity and cell proliferation was evaluated in vivo in nude mice. In vitro growth properties of the alpha5(+) TP17 cells was evaluated by cell counting and compared with that of the alpha5 parental TP17 cell line. The influence exerted by the alpha5 integrin subunit on the tumorigenic and proliferative properties of the SP6.5 cells was evaluated in vivo in nude mice by exposing the cells to increasing doses of a blocking antibody directed against the alpha5-subunit before subcutaneous injection, and compared with the results obtained with untreated SP6.5 cells. RESULTS: Expression of the alpha5 integrin subunit in the alpha5-TP17 cells was successfully achieved, as evidenced by both flow cytometry and adhesion assays on FN-coated culture plates. Restoring expression of alpha5 in TP17 cells enhanced epithelioid cell morphology and increased the growth properties of this cell line in vivo. The ability of the SP6.5 cells to yield subcutaneous tumors was found to be concentration dependent and was reduced in a dose-dependent manner when the cells were exposed to the anti-alpha5 blocking antibody. CONCLUSIONS: Restoring expression of alpha5 in the alpha5-negative TP17 uveal melanoma cell line influenced the proliferative properties of these cells but did not alter its tumorigenic potential. In contrast, the ability of the SP6.5 cells to yield tumors in vivo in nude mice appeared to be related to expression of this integrin.

Animals↗
PubMed2000

Postmenopause hormone treatment in women with NIDDM or impaired glucose tolerance: the MEDIA randomized clinical trial.

OBJECTIVE: To assess the biological safety of four hormone replacement treatment (HRT) combinations in women with non insulin dependent diabetes mellitus (NIDDM) or impaired glucose tolerance (IGT). SUBJECTS AND METHODS: Randomized, double-blind, placebo-controlled trial to analyze the variation of fibrinogen, factor VII, PAI1, and TG blood levels in women (n=99), with NIDDM or IGT, receiving a 3-month course of either oral oestradiol (1 or 2 mg) combined with Chlormadinone Acetate 5 mg, or transdermal oestradiol 50 microg/24 h in association with Norethisterone Acetate (11.2 or 22.4 mg), or placebo. Follow-up lasted 3 months. RESULTS: Ninety nine patients, mean age 56 years (SD 5), mean diabetes duration 7 years (S.D. 7), mean glycated hemoglobin (7.3%) were enrolled. There was no significant difference between the groups for any of the primary hemostasis criteria (n=77). Triglycerides (TG) variation significantly differed between groups, P=0.01, from -21% in the large patch group, to +22% in the placebo group (n=82). Treatment administration routes did not significantly differ for any of the criteria. There was a significant difference in the total cholesterol variation between groups, from +8.7% in the placebo group to -10.8% in the oral 1 mg group (P=0.001). CONCLUSION: The treatments had no highly deleterious effect in these patients with NIDDM or with IGT. Long-term trials can be performed with such patients, and an hormone treatment can be prescribed to relieve symptoms. Since these patients had a well-controlled NIDDM, results might be different in less well-controlled diabetes. The data do not support the hypothesis of an impaired oestrogen effect in patients with NIDDM.

Biomarkers↗
PubMed2000

Effects of a muramidase on a mixed bacterial community.

In bacterial communities one bacterium can influence the growth of other members of the population. These interactions may be based on nutritional factors or may occur via bacterial signaling molecules that are released in the medium. We present an example, showing that in addition to the above means of interactions, muramidases, enzymes that specifically cleave peptidoglycan chains, can also mediate interactions between bacteria. Using fluorescent in situ hybridization we demonstrate that Lactococcus lactis muramidase AcmA can hydrolyze the cell wall of Streptococcus thermophilus, without affecting viability. This intercellular activity of the lactococcal muramidase results in chain disruption of streptococci in vivo. Our data lead us to propose that chains can give growth advantages to streptococci in aerobic conditions.

Aerobiosis↗
PubMed2000

Enzyme-linked immunosorbent assays using the recombinant dense granule antigens GRA6 and GRA1 of Toxoplasma gondii for detection of immunoglobulin G antibodies.

The potential of the dense granule antigens GRA1 and GRA6 of Toxoplasma gondii to be used as diagnosis reagents in a recombinant form was evaluated. Both proteins were expressed in Escherichia coli as glutathione-S-transferase (GST) fusions. The GST-GRA1 fusion comprises the entire GRA1 sequence devoid of its N-terminal signal peptide. Separate expression of the two N- and C-terminal hydrophilic regions of GRA6 showed that only the N-terminal hydrophilic part of the protein was recognized by a pool of positive human sera in an immunoblot. One hundred T. gondii-positive and 98 negative human sera were tested in two separate immunoglobulin G (IgG)-direct enzyme-linked immunosorbent assays (ELISAs) using either GST-GRA1 or GST-GRA6-Nt recombinant protein. Whereas the sensitivity of the GST-GRA1 IgG ELISA was low (68%), the GST-GRA6-Nt IgG ELISA reached a sensitivity of 96%. The reactivity to GRA6-Nt was shown to be high even with human sera of low IgG titers. In addition, comparison of the optical density values for each serum revealed that GRA1 may complement GRA6-Nt to reach an overall sensitivity of 98%. Therefore, the GST-GRA6-Nt ELISA could be used together with another antigen like GRA1 for the development of a recombinant antigen-based test for serodiagnosis of toxoplasmosis.

Animals↗
PubMed2000

An application of theory-driven evaluation to a drop-in youth center.

This article reports on the theory-driven evaluation of a drop-in center for youth that incorporated a literature search, concept mapping with staff, and focus groups with youth. Findings revealed strong agreement among the three sources of data around specific elements identified as critical components of a program theory of global prevention in after-school-hours initiatives, such as drop-in centers. These results are used to illustrate how a theory-driven approach was relevant for the context and objectives of this evaluation, as well as how it was used to develop knowledge useful for action, social intervention theory, and further research.

Child↗
PubMed2000

[Pediatric anesthesia practice in France: a survey of 1,526 anesthesiologists].

OBJECTIVES: To assess the individual activity of anaesthetists in paediatric anaesthesia (PA), and collect their wishes about continuing education and recommendations in PA. STUDY DESIGN: Transversal, prospective study. METHODS: A questionnaire of 33 items, sent to 4,360 anaesthetists, spread over 15 health districts, working in a public or private institution. RESULTS: We gathered 1,526 replies (35%) of which 34% university hospitals, 32% public institutions and 31% private institutions. 943 physicians (63%) had no specific structure, and 1,119 (87%) considered a specialized nurse to be essential for PA. 1,127 physicians (74%) had undertaken a specific session during their formation. The practice of PA depends upon age and context. Above 1 year old, the surgery that is performed weekly was ENT (38%), abdominal and urologic surgery (28%). Mask induction was performed by 60% of the physicians in children under 5 years. 63% of the anaesthetists dreaded a laryngospasm during induction. 625 physicians undertook regional anaesthesia in children under 5 years (87% caudal anaesthesia, 48% peripheral nerve blocks). 1,029 physicians (67%) wished for recommendations in PA in children under 12 months. CONCLUSIONS: This survey showed that most of the anaesthetists wished for recommendations in their paediatric anaesthesia practice.

Adult↗
PubMed2000

[Hope and deficiency: community mental health and severe mental disorders].

Over the second half of the twentieth century, the way in which Canadian society treats people with mental challenges has changed radically, from exclusion and containment in asylums to reintegration and maintenance in the community. Now that deinstitutionalization is practically complete, the objective has increasingly shifted from reintegrating people with severe mental challenges in their communities to upholding their rights and ensuring that they have access to resources allowing them to assume their responsibilities and roles as citizens. This change of vision results in a completely different set of issues for community mental health. Given the prejudices surrounding mental illness, the capacity of community mental health professionals to play a mediating and facilitating role becomes a determining factor in successfully reestablishing and re-empowering people with severe mental challenges. The advances that have clearly been made give cause for hope, but in the context of the unwanted effects of deinstitutionalization and unfavourable socioeconomic conditions, significant obstacles still need to be overcome before people with severe mental challenges can participate fully in the life of the collectivity.

Canada↗
PubMed1999

Differential membrane targeting of the secretory proteins GRA4 and GRA6 within the parasitophorous vacuole formed by Toxoplasma gondii.

Following secretion into the parasitophorous vacuole, dense granule proteins, referred to as GRA proteins, are targeted to different locations including a complex of tubular membranes that are connected with the vacuolar membrane. To further define the formation of this intravacuolar network, we have investigated the secretion, trafficking and membrane association of GRA4 and GRA6 within the parasitophorous vacuole. In extracellular parasites, GRA4 and GRA6 were found exclusively in dense secretory granules where they were packaged primarily as soluble proteins. Following release into the vacuole, GRA6 was rapidly translocated to the posterior end of the parasite where, like previously reported for GRA2, it bound to a cluster of multi-lamellar vesicles that give rise to the network. In contrast, GRA4 was distributed throughout the lumen of the vacuole and only later became associated with the mature network that is found dispersed throughout the vacuole. Cell fractionation and treatment with denaturing agents established that the association of GRA4 with the network membranes was mediated by strong protein-protein interactions. In contrast, GRA6 was predominantly influenced by hydrophobic interactions, and a phosphorylated form of this protein present within the vacuole showed increased association with the network membranes. Cross-linking studies established that GRA4 and GRA6 specifically interact with GRA2 to form a multimeric complex that is stably associated with the intravacuolar network. Formation of this protein complex, which is based on both protein-protein and hydrophobic interactions, may participate in nutrient or protein transport within the vacuole.

Animals↗
PubMed1999

Effects of hindlimb suspension on contractile properties of young and old rat muscles and the impact of electrical stimulation on the recovery process.

The purpose of this study was to investigate the effects of hindlimb suspension (HS) on contractile properties of skeletal muscles of young and old rats and to determine the impact of electrical stimulation (ES) on the quality and degree of recovery of these muscles. After 21 days of HS, young soleus (SOL) muscle became faster, but there was no impact on young extensor digitorum longus (EDL) muscle. Twitch tension (Pt) decreased 61% in young and 70% in old SOL muscles. Specific tetanic tension (Po) decreased 53% in young and 64% in old SOL muscles, but again there was no impact on EDL muscle. After a 14-day period of recovery, contraction time (CT), half-relaxation time (RT1/2), Pt and Po returned to control group values in both young and old SOL muscles. Measurements of the contractile properties of young and old skeletal rat muscles showed ES sometimes to be beneficial but also sometimes to be harmful. A 14-day period of recovery, with or without ES, seemed sufficient for many variables to return to control group values.

Aging↗
PubMed1999

The role of ultrasonography in imaging of paediatric head trauma.

Ultrasound appears to be a promising tool for assessment of the state of the dura in patients suffering from a diastatic skull fracture. Our goal is to identify patients who are at a high risk of developing the complications associated with this type of fracture as early as possible in order to keep the neurosurgical repair as simple as possible.

Algorithms↗
PubMed1999

Validation of a biophysical drug absorption model by the PATQSAR system.

Absorption rate constants (in situ rat gut technique) and in vitro antibacterial activities of twenty fluoroquinolones have been evaluated. A biophysical model that relates the absorption of the compounds with their lipophilicity was fitted. The model considers the absorption process from the intestinal lumen as the sum of two resistances in series: aqueous diffusional barrier and lipoidal membrane. Even if partitioning into the membrane and membrane diffusion are both enhanced for lipophilic compounds, the absorption rate constant is limited by the aqueous diffusion. To estimate the influence of structural modifications on each property and to establish the role of lipophilicity in controlling in situ absorption and in vitro antibacterial activity, the PATQSAR search system is used to construct structure-property relationships. The structural models, which explain 99% of the total variance of each physicochemical property and 96% of each in vitro biological activity, provide an explicit and precise interpretation of lipophilicity, absorption, and antimicrobial activity. The results confirm the important role of lipophilicity in controlling absorption, as pointed out by the biophysical model for the piperazinyl series, and suggest the introduction of electronic factors in order to extend the model to heterologues. They also justify the mechanism by which quinolones are assumed to induce antibacterial activity.

Algorithms↗