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Biomedical subjects

C Mercier

Publications and source records attributed to C Mercier.

At least 55 records · Page 3Linked to original sources
PubMed1999

An evaluation of psychometric properties of the client's questionnaire of the Wisconsin Quality of Life Index-Canadian version (CaW-QLI).

Psychometric properties of Client's questionnaire from the Canadian version of the Wisconsin Quality of Life-Index (CaW-QLI) were assessed with two groups, 89 English (E) and 94 French (F) individuals with schizophrenia or schizoaffective disorder. Sub-samples of 40 E and 36 F were re-interviewed within a 2-week period. Spearman correlations-SC between each domain and CaW-QLI global Score ranged from 0.39 to 0.76, while interdomain correlations were low, confirming the multi-dimensional properties of the scale. Cronbach's alpha (internal consistency) were 0.78 (E) and 0.70 (F) for the CaW-QLI global scores and, from 0.45 to 0.88 among seven of eight domains. Test-retest (Concordance Correlation Coefficient--CCC) ranged from 0.36 to 0.80 among the domains, and from 0.80 (E) and 0.85 (F) between CaW-QLI global scores. Regarding convergent validity, SC between CaW-QLI global score and Spitzer's QOL-Index were 0.72 (E) and 0.58 (F). As hypothesized, there were higher correlations between CaW-QLI global scores (E and F) and SF-36 scales related to mental health than those related to physical health. Minor changes in the scoring are proposed to enhance face and content validity.

Adolescent↗
PubMed1999

Transmembrane insertion of the Toxoplasma gondii GRA5 protein occurs after soluble secretion into the host cell.

The intracellular parasite Toxoplasma gondii resides within a specialized compartment, the parasitophorous vacuole (PV), that resists fusion with host cell endocytic and lysosomal compartments. The PV is extensively modified by secretion of parasite proteins, including the dense granule protein GRA5 that is specifically targeted to the delimiting membrane of the PV (PVM). We show here that GRA5 is present both in a soluble form and in hydrophobic aggregates. GRA5 is secreted as a soluble form into the PV after which it becomes stably associated with the PVM. Topological studies demonstrated that GRA5 was inserted into the PVM as a transmembrane protein with its N-terminal domain extending into the cytoplasm and its C terminus in the vacuole lumen. Deletion of 8 of the 18 hydrophobic amino acids of the single predicted transmembrane domain resulted in the failure of GRA5 to associate with the PVM; yet it remained correctly packaged in the dense granules and was secreted as a soluble protein into the PV. Collectively, these studies demonstrate that the secretory pathway in Toxoplasma is unusual in two regards; it allows soluble export of proteins containing typical transmembrane domains and provides a mechanism for their insertion into a host cell membrane after secretion from the parasite.

3T3 Cells↗
PubMed1999

Description of a new motor re-education programme for the paretic lower limb aimed at improving the mobility of stroke patients.

OBJECTIVE: To describe and examine the feasibility of a new treatment approach for the paretic lower limb and to explore its effectiveness in one chronic hemiparetic stroke subject. DESIGN: Case report. The treatment was conducted three times per week over a period of six weeks. The mobility of the patient was assessed prior to the treatment, at the end of the treatment and at a six-week follow-up. SETTINGS: The study was carried out at the research centre of the Institut de réadaptation de Montréal. The treating therapist was an experienced rehabilitation professional as was the assessor, who worked at a different rehabilitation centre. INTERVENTIONS: The motor re-education programme was based on the use of a static dynamometer that measures the linear external forces produced at the ankle level. A computer program provided the subject with constant feedback on the direction and intensity of the applied force. In each treatment session, the subject was asked to produce several submaximal efforts in 16 specific directions. Both the intensity and the number of repetitions were gradually increased. OUTCOME MEASURES: In addition to force production measurements, three clinical assessments of mobility were used: the Timed 'Up and Go', the comfortable gait speed and a 2-minute walk test. RESULTS: The maximal static linear forces produced by the subject increased through the treatment for all directions of effort, but differences were observed amongst directions. During the treatment programme, the subject improved his performance at the three clinical assessments. Even if some of the functional gain was lost at the follow-up, the mobility was still considerably improved as compared to baseline values. CONCLUSION: This study demonstrated the applicability of the treatment programme to a stroke subject. The results seem very promising and encourage further investigation in order to assess more rigorously the effectiveness of this new approach.

Adult↗
PubMed1999

[Prognostic importance of ambulatory arterial pressure monitoring in France. Initial results of the OCTAVE II study. OCTAVE II Research Group].

RATIONALE: Ambulatory blood pressure measurement (ABPM) is commonly used in clinical practice, whereas its added value to the management of hypertension is not definitely documented. OBJECTIVE: The OCTAVE II study was launched in 1991 to explore the prognostic value of ABPM, compared to that of the gold standard, the clinical blood pressure measurement. METHODS: Two hundred and six French cardiologists recruited 3569 participants over 18 years of age, provided they deemed ABPM was useful (mean age of 56 years, 52% of men, 65% already treated by antihypertensive drugs). The prognostic value of various blood pressure measurements, systolic or diastolic, clinical or ambulatory (diurnal, nocturnal or during 24 hours), has been assessed in multivariate models adjusted on the baseline characteristics associated with risk. The outcome was the occurrence of a major cardiovascular event, including stroke, myocardial infarction and cardiovascular death. RESULTS: After an average follow-up of five years, cardiovascular morbidity was known for 85% of the participants, and their vital status for 91%. On the whole population, the best prognostic indicators were systolic blood pressure compared with diastolic, ABPM compared with clinical blood pressure measurements, and nocturnal ABPM compared with diurnal ABPM. In the untreated participants at baseline, cardiovascular risk regularly increased among the four groups: normotensives, white-coat hypertensives, dippers, non-dippers. Between the extreme categories, the cardiovascular event rate was multiplied by 6.5. CONCLUSION: In this French population, ABPM and most of all its nocturnal component, was better correlated with cardiovascular prognosis. It remains to assess: 1) the general value of our findings, 2) the respective values of self blood pressure measurement versus ABPM, and 3) whether ABPM allows a better risk prevention.

Adult↗
PubMed1998

Difference between arterial and end-tidal carbon dioxide pressures during laparoscopy in paediatric patients.

PURPOSE: To assess the effect of pneumoperitoneum on P(a-ET)CO2 gradient in children. METHODS: Sixty one ASA I and II children (10.7 +/- 3.0 yr, 38.4 +/- 14.2 kg, mean +/- SD), scheduled for visceral or urological laparoscopic procedures, were studied. They were anaesthetized, intubated, paralysed and their lungs ventilated with constant ventilator settings to obtain PETCO2 values between 4.3 and 4.8 kPa. Intra-abdominal pressure was maintained between 8 and 14 mmHg. The following measurements were performed at steady state, before the pneumoperitoneum (T1) and 15 min later (T2): heart rate, systolic and diastolic arterial pressure; peak airway and intra-abdominal pressure; PaCO2 corrected for the patient's temperature; PETCO2 drawn between the micropore filter and the ventilator tubes, corrected for BTPS conditions; P(a-ET)CO2. Values between -1.0 and +1.0 mmHg were considered nil; patient position (horizontal or head-down tilt): all patients were horizontal at T1. RESULTS: Arterial pressure, heart rate and peak airway pressure increased at T2: PaCO2 and PETCO2 increased by 14%. The incidence of negative gradients increased from 54 to 67% although mean P(a-ET)CO2 remained clinically unchanged. No difference was found in P(a-ET)CO2 gradient, whatever the position and intra-abdominal pressure. The 95% confidence intervals for P(a-ET)CO2 were [-5.6; +3.2] at T1 and [-8.8; +4.8] at T2. CONCLUSION: PETCO2 often overestimates PaCO2 during laparoscopy in children, by up to 8.8 mmHg. Arterial blood gas analysis should be performed during long procedures to avoid hyperventilation.

Abdomen↗
PubMed1998

Airbags and children: a spectrum of C-spine injuries.

Over 30 children who were improperly restrained or in rear facing safety seats have been reported killed in motor vehicle accidents (MVA) involving airbags. The authors report one minor and two major injuries in properly restrained children in the front passenger seat. In case 1, A 10-year-old seat-belted boy was involved in an MVA (40 km/h) with deployment of both airbags. Physical examination findings showed right hyphema with corneal abrasion, right cheek abrasion and minimal cervical tenderness. C-spine x-ray was normal. He was treated for whiplash and facial burns resulting from contact with hot gas released by the airbags and discharged. In case 2, a 4-year-old boy wearing a lapbelt was in a MVA (20 km/h) with airbag deployment. On arrival, his Glasgow coma score was 3 and he was hemodynamically unstable. Secondary survey after stabilization showed left neck abrasions and ecchymoses, quadraplegia, priapism, and absent rectal tone. C-spine x-ray showed atlanto-occipital dislocation with possible complete spinal cord transection at C1. Aggressive maneuvers were withheld, and the patient was pronounced dead. Autopsy findings confirmed the clinical diagnosis. In case 3, a 3-year-old boy in a forward-facing safety seat was in a MVA (60 km/h) with air bag deployment. The patient was fully awake. C-spine x-rays were normal. Because of fluctuating level of consciousness, he underwent head computed tomography (CT) scan, which demonstrated a posterior fossa subarachnoid hemorrhage and a hematoma posterior to the odontoid, suggesting a ligamentous tear. He remained asymptomatic and was discharged on day 6. A head CT scan at 1 month showed a periosteal reaction in the area of the alar ligament suggestive of partial ligamentous avulsion; this injury was the forerunner of atlanto-occipital dislocation. Airbags deploy by releasing a hot effluent at 300 km/h. Mechanisms of injury include direct contact of hot gas with facial skin and energy transmitted directly from the airbag system to the child's head and neck. These cases illustrate a spectrum of C-spine injuries caused by airbag deployment and support the recommendation that children under 12 years of age travelling in a car equipped with dual airbags be seated in the back.

Accidents, Traffic↗
PubMed1998

[Prolonged neuromuscular blockade with mivacurium in a newborn].

Mivacurium is a short acting non-depolarising neuromuscular blocking agent. Short duration of action is due to a rapid hydrolysis by plasma cholinesterase (CHe). The duration of neuromuscular blockade can be prolonged by an abnormal variant of CHe. We report a case of a newborn with neuromuscular blockade for a duration of 8 hours following mivacurium 0.2 mg.kg-1. CHe activity values were not contributive for the diagnosis. The diagnosis was obtained with molecular study showing the new-born homozygocity. The whole family was heterozygous. This case emphasises the lack of precision of CHe activity measurement during the first 6 months of life.

Cholinesterases↗
PubMed1998

[Emergency EEG and brain injuries].

The aim of this study is to review indications for emergency EEG in case of brain trauma. The authors emphasize the indication of emergency EEG for the diagnosis of either cerebral death or early post traumatic seizures, and for the monitoring of intensive neurological treatments. Emergency EEG and diagnosis of cerebral death has been reviewed in another issue of this journal. Diagnosis of early post-traumatic seizures may be difficult in case of cranial trauma in either the presence or the absence of coma. Emergency EEG help guide the diagnosis of electrical signs of seizures, thus indicating that treatment with antiepileptic drugs is advisable. Severe post-traumatic coma requires barbiturate impregnation and moderate hypothermia. In this last case, emergency EEG is essential for the monitoring of pharmacological treatments. The authors conclude that continuous EEG monitoring could in the future substitute for standard EEG recorded in emergency.

Brain Death↗
PubMed1998

Quality of life of severely mentally ill individuals: a comparative study.

This survey compared the subjective quality of life (SQOL) of severely mentally ill patients (n = 59) receiving community support services with a random sample from the general population members (n = 253) and welfare recipients (n = 79). Research participants lived in two cities of Northwest Quebec. The Satisfaction with Life Domain Scale (Baker & Intagliata, 1982) was used in face to face interviews, and also administered as a mail-in questionnaire for the general population. Results show that patients' subjective quality of life as-a-whole is lower than the general population. Mentally ill patients were more satisfied with material domains (e.g., housing and finances) than welfare recipients. However, mentally ill patients were less satisfied with interpersonal relationships, including people they live with, family members and their love life.

Adolescent↗
PubMed1998

Components of social support and quality of life in severely mentally ill, low income individuals and a general population group.

Satisfaction with social support and quality of life (QOL) were assessed for 60 psychiatric patients, 79 welfare recipients and 266 people of the general population using the Social Provisions Scale (SPS) and the Satisfaction with Life Domains Scale (SLDS). Psychiatric patients reported less satisfaction than the general population on all components of social support. They have a comparable level of satisfaction with welfare recipients on most of the components, with the exception of emotional integration and opportunity for nurturance. However, patients satisfaction with QOL was quite similar to the general population, although higher than welfare recipients on some dimensions. Their lower satisfaction with the personal-intimate dimension suggest deficiencies in social support. All components of social support were consistently related to QOL in the general population. Attachment and reassurance of worth was significant for psychiatric patients but only attachment was related to QOL for the welfare recipients group. The pairing of SPS and SLDS scales seem to be good instruments for discriminating the majority of psychiatric patients.

Adult↗
PubMed1998

Age, gender and quality of life.

This paper addresses the effect of age and gender on the subjective quality of life of people with severe and persistent mental illness. Subjective quality of life was assessed in a group of 95 men and 70 women using the Satisfaction with Life Domains Scale (SLDS) and five open-ended questions. Although statistical analyses showed no difference between men and women on quality of life, age was systematically related to satisfaction level with older participants being more satisfied with their lives than their younger counterparts. Responses to the open-ended questions revealed that fewer of the older, more satisfied respondents expressed worries, desire for change and plans for the future. These results are discussed with respect to the links between subjective quality of life, aspirations and the rehabilitation process.

Adult↗
PubMed1998

Enhancing the flexibility and adaptability of the DARC structural representation for computer-aided drug design.

Noticeable progress has been achieved in the determination of dynamic topochromatic variables for the structural representation of compounds and their situation in a given population. These independent structural variables can be further combined into more complex variables. Their contributions to the evolution of an associated property can therefore be evaluated with certainty. The risk of having correlated variables is avoided while the structural description remains exhaustive. In order to enhance the interpretative ability of the QSAR model, one or several physicochemical properties can be taken with these structural parameters as explanatory variables. Typically, partition coefficients, 3-D and quantum mechanical data are used for this purpose. The structural aspects not taken into account by the physicochemical parameters are reflected in the remaining topochromatic variables. The use of these new concepts is presented in a study of carbazole mutagenicity. The model explains 99% of the total variance with one external property and four additional topochromatic variables. The modulation of the heat of formation of an intermediate by two topochromatic variables suggests a much more precise interpretation than a simple combination of the usual external variables.

Animals↗
PubMed1998

Estimation of the state of the bacterial cell wall by fluorescent In situ hybridization.

Fluorescent in situ hybridization (FISH) is now a widely used method for identification of bacteria at the single-cell level. With gram-positive bacteria, the thick peptidoglycan layer of a cell wall presents a barrier for entry of horseradish peroxidase (HRP)-labeled probes. Therefore, such probes do not give any signal in FISH unless cells are first treated with enzymes which hydrolyze the peptidoglycan. We explored this feature of FISH to detect cells which have undergone permeabilization due to expression of autolytic enzymes. Our results indicate that FISH performed with HRP-labeled probes provides a sensitive method to estimate the states of cell walls of individual gram-positive bacteria.

Amidohydrolases↗
PubMed1998

Targeted disruption of the GRA2 locus in Toxoplasma gondii decreases acute virulence in mice.

Following invasion into the host cell, the protozoan Toxoplasma gondii secretes a variety of proteins that modify the parasitophorous vacuole. Within the vacuole, the 28-kDa dense granule protein known as GRA2 is specifically targeted to the tubulovesicular network which forms connections with the vacuolar membrane. To investigate the importance of GRA2, we derived from strain RH a mutant T. gondii line in which GRA2 was disrupted by replacement with the marker Ble (selecting for phleomycin resistance). The Deltagra2 mutant invaded and grew normally in both fibroblasts and macrophages in vitro; however, it was less virulent during acute infection in mice. The survival rate of mice inoculated with Deltagra2 was significantly higher; some infected mice survived the acute infection, whereas all mice infected with the wild-type strain RH succumbed to early death. Chronic infection by Deltagra2 was detected by positive serology, immunohistochemical detection of parasites and cysts in the brain, and reisolation of parasites by bioassay at 6 weeks postinfection. Thus, absence of GRA2 partially attenuates the virulence of T. gondii during the acute phase of infection and allows for establishment of chronic infection by the otherwise highly virulent RH strain. These results establish that GRA2 plays an important role during in vivo infection and provide a potential model for examining acute pathogenesis by T. gondii.

Animals↗
PubMed1998

The amphipathic alpha helices of the toxoplasma protein GRA2 mediate post-secretory membrane association.

The Toxoplasma gondii protein GRA2 is secreted into the parasite-containing vacuole where it is rapidly and specifically targeted to a network of membranous tubules that connect with the vacuolar membrane. To examine the molecular basis of this association, we expressed an HA9 epitope-tagged form of GRA2 by stable transformation of Toxoplasma. GRA2-HA9 was correctly packaged inside the dense granules, secreted into the PV and targeted to the network, as shown by immunoelectron microscopy, immunofluorescence and cell fractionation. Expression of deletion mutants of GRA2-HA9 lacking either of two amphipathic alpha helices resulted in the production and secretion of soluble proteins which were unable to stably associate with the network. A mutant in which the amino acids of the first alpha helix were rearranged to a non-amphipathic pattern localized correctly to the network but failed to remained stably associated with the membrane. Collectively, these results demonstrate that targeting and membrane association occur by separate mechanisms and that the combination of both alpha helices is essential for stable localization of GRA2 to the network.

Amino Acid Sequence↗
PubMed1998

[Bladder paraganglioma (pheochromocytoma): a rare tumor in children. Apropos of a case].

The authors report the first case of bladder paraganglioma in a child admitted to their department successfully treated by partial cystectomy. The diagnosis was established histologically, after failure of clinical diagnosis. Retrospectively' the authors think that preoperative diagnosis should have been possible and emphasize the importance of a thorough clinical examination.

Child↗