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Biomedical subjects

C Brisson

Publications and source records attributed to C Brisson.

At least 19 recordsLinked to original sources
PubMed2006

Development and implementation of a participative intervention to improve the psychosocial work environment and mental health in an acute care hospital.

OBJECTIVES: To describe the development and implementation phases of a participative intervention aimed at reducing four theory grounded and empirically supported adverse psychosocial work factors (high psychological demands, low decision latitude, low social support, and low reward), and their mental health effects. METHODS: The intervention was realised among 500 care providers in an acute care hospital. A prior risk evaluation was performed, using a quantitative approach, to determine the prevalence of adverse psychosocial work factors and of psychological distress in the hospital compared to an appropriate reference population. In addition, a qualitative approach included observation in the care units, interviews with key informants, and collaborative work with an intervention team (IT) including all stakeholders. RESULTS: The prior risk evaluation showed a high prevalence of adverse psychosocial factors and psychological distress among care providers compared to a representative sample of workers from the general population. Psychosocial variables at work associated with psychological distress in the prior risk evaluation were high psychological demands (prevalence ratio (PR) = 2.27), low social support from supervisors and co-workers (PR = 1.35), low reward (PR = 2.92), and effort-reward imbalance (PR = 2.65). These results showed the empirical relevance of an intervention on the four selected adverse psychosocial factors among care providers. Qualitative methods permitted the identification of 56 adverse conditions and of their solutions. Targets of intervention were related to team work and team spirit, staffing processes, work organisation, training, communication, and ergonomy. CONCLUSION: This study adds to the scarce literature describing the development and implementation of preventive intervention aimed at reducing psychosocial factors at work and their health effects. Even if adverse conditions in the psychosocial environment and solutions identified in this study may be specific to the healthcare sector, the intervention process used (participative problem solving) appears highly exportable to other work organisations.

Adaptation, Psychological↗
PubMed2006

Effectiveness of a participative intervention on psychosocial work factors to prevent mental health problems in a hospital setting.

OBJECTIVES: To assess the effectiveness of a workplace intervention aimed at reducing adverse psychosocial work factors (psychological demands, decision latitude, social support, and effort-reward imbalance) and mental health problems among care providers. METHODS: A quasi-experimental design with a control group was used. Pre-intervention (71% response rate), and one-year post-intervention measures (69% response rate) were collected by telephone interviews. RESULTS: One year after the intervention, there was a reduction of several adverse psychosocial factors in the experimental group, whereas no such reduction was found in the control group. However, there was a significant deterioration of decision latitude and social support from supervisors in both experimental and control groups. There was also a significant reduction in sleeping problems and work related burnout in the experimental hospital, whereas only sleeping problems decreased in the control group while both client related and personal burnout increased in this hospital. The comparison between the experimental and control groups, after adjusting for pre-intervention measures, showed a significant difference in the means of all psychosocial factors except decision latitude. All other factors were better in the experimental group. CONCLUSION: Results suggest positive effects of the intervention, even though only 12 months have passed since the beginning of the intervention. Follow up at 36 months is necessary to evaluate whether observed effects are maintained over time. In light of these results, we believe that continuing the participative process in the experimental hospital will foster the achievement of a more important reduction of adverse psychosocial factors at work. It is expected that the intensity of the intervention will be directly related to its beneficial effects. Long term effects will however depend on the willingness of management and of staff to appropriate the process of identifying what contributes to adverse psychosocial factors at work and to adopt means to reduce them.

Adolescent↗
PubMed2003

[Prospective epidemiological study on cutaneous melanomas in the Vendée area].

INTRODUCTION: The aim of this prospective study was to evaluate the incidence of melanoma in the Vendée area, coastal region of Eastern France, in 1997. PATIENTS AND METHODS: The 16 dermatologists in the Vendée area in 1997, grouped together in a local association, completed a sheet for each patient in whom a new melanoma had been diagnosed. During the same period, the hospital and private pathologists of the Vendée and surrounding areas reported their new cases of melanoma in patients residing at least six months of the year in the area. The data concerning the local population was supplied by the INSEE (French national institute of economic and statistical information) and the CPAM (French health authority) supplied data on the practitioners' activity. The raw and standardized incidence was calculated by the epidemiologist and the statistician of the local Vendée Cancer registry. RESULTS: One hundred fifteen new melanomas were diagnosed in Vendée in 1997, 97 by a dermatologist and 18 declared by a pathologist. There were 36 in situ and 79 invasive melanomas discovered in 68 women and 47 men (sex ratio: 1.46). The standardized rate of incidence according to the world model was of 98/100,000 for women and 7.8/100,000 for men. The frequency curve revealed two peaks: the first at 40-50 years of age and the second at 70-75. The mean Breslow index of the 79 invasive cancers was of 1.62 mm (range: 0.10-12.5 mm). The only statistically significant difference between the melanomas of the men and the women concerned the topography; there were more melanomas on the trunk in men and more melanomas on the lower limbs in the women. Forty-seven Dubreuilh melanomas were reported: 28 in situ and 19 invasive. DISCUSSION: This prospective study determined the incidence of melanoma in Vendée in 1997. The figures have been compared with those of the Vendée cancer registry, founded in April 1997, and with those of various published studies. The comparison was difficult because of the difference in study methodology. The only figures obtained in the same conditions are those of the cancer registry and we compared them with those of the Haut-Rhin, area of Eastern France: the incidence was similar for the women in the two areas and greater for the men in the Haut-Rhin with regard to the invasive melanomas. Conversely, 44 in situ melanomas were declared in the Haut-Rhin over a 3 year period versus 37 in Vendée over a period of 1 year. The increase in the incidence of melanoma in Vendée in the years to come should permit the evaluation of the impact of the various preventive campaigns.

Adult↗
PubMed2003

[Prospective clinical study on new cutaneous melanomas in the Vendée area].

INTRODUCTION: In parallel to an epidemiological study on the new cases of melanoma reported in the Vendée area in 1997, private dermatologists conducted a clinical analysis of the characteristics of melanomas (including Dubreuilh's melanoma) and of the population concerned. PATIENTS AND METHODS: For each patient in whom a melanoma had been diagnosed, the dermatologists completed a standardized sheet that included the identification, phototype (comparing the distribution with that of the local population, studied in all the consultants during a randomly selected week), the personal and family history of melanoma, the existence of severe sunburn and exposure to artificial ultra-violet rays, the screening method, the time lapse before treatment, the impact of information campaigns, the number of nevi, atypical or not, and the characteristics of the tumor. The exeresis method and the histological characteristics (type, Clark's score and Breslow's index) were also noted. RESULTS: In 1997, the 16 local dermatologists diagnosed 97 melanomas in 55 women and 42 men with a mean age of 64 years. There was no statistically significant difference between the melanomas of the men and those of the women, other than their localization. Photoype II was significantly more frequent in the population exhibiting a melanoma. Sun exposure was moderate or intensive for three thirds of the patients. Past history of severe sunburn was twofold more frequent in the patients exhibiting a melanoma on the trunk. The association of many nevi was noted in a little more than half of the patients, and with atypical nevi in 5.2 p.cent. The elements that alerted the patients were recorded. The time lapse before diagnosis was calculated in months for nodular and in years for superficial melanomas. Clark's score and Breslow's index are presented in a table. DISCUSSION: Our study underlines several interesting features: the fairly high mean age on discovery, a high rate of invasive melanomas, and patients less well informed than in the Ile de France area. These results should open the debate on the best way to educate the population concerned so as to reduce the incidence of this malignant tumor.

Adult↗
PubMed2002

Establishment of human tumoral ependymal cell lines and coculture with tubular-like human endothelial cells.

Ependymomas, rare neoplasms of the central nervous system, occur predominantly in children. They are highly vascularized, and histological findings show many perivascular rosettes of tumoral cells radially organized around capillaries. Treatment of ependymomas relies on surgery combined with radio- or chemotherapy, but the efficiency of chemotherapy is limited, probably because of their multidrug resistance (MDR) phenotype. Progress in the therapy of these neoplasms is dramatically limited by the absence of cell line models. We established conditions for the long-term culture of human tumoral ependymocytes and their 3D coculture in Matrigel with endothelial cells. Histological, immunological, and ultrastructural studies showed that the morphological features (microvilli, cilia, and caveolae) of these cultured cells were similar to those of the tumor in vivo. The cells expressed potential oncological markers related to the immature state of tumoral cells (nestin and Notch-1), their tumorigenicity [caveolae and epidermal growth factor-receptor (EGF-R)], or the MDR phenotype [P-glycoprotein (P-gp)]. The expression of P-gp, EGF-R, and caveolin-1 by these tumoral ependymocytes could be useful in studies on new drugs. This coculture model might represent a new powerful tool to study new therapeutic delivery strategies in tumoral cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Differential expression of somatostatin receptors in medulloblastoma.

OBJECT: Somatostatin receptors have been found on a variety of tumours like neuroendocrine breast or brain tumours. Their detection opens new diagnostic and therapeutic paths. The aim of this work was to investigate their expression in medulloblastomas. METHODS: Using both techniques, reverse transcriptase-polymerase chain reaction and immunohistochemistry, we analysed mRNA of different subtypes of somatostatin receptors in 15 medulloblastomas and the localisation of the subtype SSTR2 receptor at the cellular level in 13 medulloblastomas. All five subtypes mRNA were variably expressed in each medulloblastoma. The signal obtained after Southern blotting for SSTR2 receptor amplification was the highest as compared to the signal obtained for the other receptor subtypes. Immunostaining for SSTR2A receptor was present in every tumour specimen and was specifically located to the cellular membrane of neoplastic cells. No staining was identified at the level of peritumoral veins. CONCLUSION: The evidence of predominant expression of SSTR2 receptors in medulloblastomas opens interesting prospects for their diagnosis and therapy.

Cerebellar Neoplasms↗
PubMed2000

Astrocytic alterations induced by HTLV type 1-infected T lymphocytes: a role for Tax-1 and tumor necrosis factor alpha.

In the neurological disease associated with HTLV-1 infected T lymphocytes infiltrated within the CNS are suspected of playing a prominent role in pathogenesis via inflammatory cytokines and the viral protein Tax-1. We hypothesized that T lymphocytes initiate functional perturbation in astrocytes, resulting in neuronal alteration as glial cells have a crucial role in CNS homeostasis. In particular, astrocytes manage the steady state level of glutamate and continuously provide metabolite precursors to neurons and oligodendrocytes. Using a model system of HTLV-1-infected T cells-astrocytes interaction, we show that after contact with T cells, astrocyte acquire a phenotype typical of gliosis: secretion of proinflammatory cytokines (TNF-alpha, IL-1alpha, IL-6) and matrix metalloproteinases (MMP-9, MMP-3). The concomitant increase in the expression of MMPs and of their endogenous inhibitors (TIMP-1 and TIMP-3) suggests a perturbation in MMP/TIMP balance. This may alter the extracellular matrix and, in turn, the cell environment. At a functional level, glutamate transport and catabolism are impaired in astrocytes. A decrease in glutamate uptake is associated with downregulated expression of glutamate transporters GLAST and GLT1. The expression of astrocytic enzyme of glutamate metabolism is modified with up-regulation of glutamine synthetase and down-regulation of glutamate dehydrogenase. The involvement of Tax-1 in these alterations, directly or indirectly via TNF-alpha, is shown. Altered glutamate uptake and catabolism associated with impairment in cell connectivity via MMP/TIMP imbalance could compromise the functional integrity of the CNS in general and that of neurons and oligodendrocytes in particular.

Animals↗
PubMed2000

In vivo subcellular target compartments of interferon-gamma and interferon-gamma receptor (alpha- and beta-chains) in mouse liver.

IFN-gamma displays several effects on different tissues via its specific cell surface receptor (IFN-gammaR). In order to identify the target compartments of IFN-gamma and IFN-gammaR (alpha and beta-chains), we used a quantitative immunogold approach. In physiological conditions, IFN-gamma and IFN-gammaR immunoreactivities were detected in the plasma membrane, in the endoplasmic reticulum area, in the mitochondria and in the nucleus. After a single IFN-gamma injection, we observed, in a quantitative manner, an increase of signal density without modification of the subcellular distribution of IFN-gamma and IFN-gammaR subunits.

Animals↗
PubMed2000

Psychosocial factors at work, smoking, sedentary behavior, and body mass index: a prevalence study among 6995 white collar workers.

This cross-sectional study examined whether psychosocial factors at work were associated with smoking, sedentary behavior, and body mass index. The study population was composed of 3531 men and 3464 women employed as white collar workers in 21 organizations. Data were collected at worksites. Psychological demands and decision latitude at work were measured with the Karasek 18-item questionnaire. Smoking, sedentary behavior, and mean body mass index were compared by quartiles of decision latitude and psychological demands and by job strain categories. Prevalence of smoking, mean number of cigarettes smoked per day, prevalence of sedentary behavior, and mean body mass index were not consistently associated with decision latitude, psychological demands, or high job strain. However, prevalence of smoking was elevated in women belonging to the highest quartile of psychological demands (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.0 to 1.6) and in the active job strain groups in both men (OR, 1.6; 95% CI, 1.2 to 2.1) and women (OR, 1.4; 95% CI, 1.0 to 2.0). Prevalence of sedentary behavior was elevated in men in the lowest quartile of decision latitude (OR, 1.3; 95% CI, 1.0 to 1.7), in the passive group (OR, 1.3; 95% CI, 1.0 to 1.5), and in the high strain group (OR, 1.2; 95% CI, 1.0 to 1.6). In women, this prevalence was elevated in the third quartile of psychological demand (OR, 1.3; 95% CI, 1.1 to 1.6). These results provide only partial support for an association between some psychosocial factors at work and the prevalence of smoking and sedentary behavior.

Adolescent↗
PubMed2000

Long-term effects of HTLV-1 on brain astrocytes: sustained expression of Tax-1 associated with synthesis of inflammatory mediators.

HTLV-1 is the causative agent of a chronic neurological disease, TSP/HAM. The persistently activated CTL response to the viral protein Tax-1 suggests the existence of persistent viral replication with continuous expression of Tax-1. Although CD4+ T-cell is the main target for HTLV-1, previous observations have indicated that the astrocyte, the major neural cell in close contact with blood vessel and thus with HTLV-1-infected T-cells infiltrating the CNS, may also be infected. We tested in vitro the hypothesis of persistent/restricted infection in human and rat astrocytes after transient contact with an infectious T-cell line (C91PL). Long-term analysis showed prolonged expression of Tax-1 in astrocytes, associated with secretion of inflammatory mediators (TNFalpha, IL1alpha, MMP-2, and MMP-9). These data suggest a possible contribution of Tax-1-expressing astrocytes to TSP/HAM pathogenesis.

Animals↗
PubMed1999

In vitro embryo production in the cow: an effective alternative to the conventional embryo production approach.

Development of new technology related to in vitro embryo production has allowed for the commercial use of this method of reproduction. In the present work, we evaluate the efficiency of this technology compared with conventional embryo production based on results obtained with a standard procedure, including the sexing of embryos. The donor animals were mature nonlactating dairy cows (n = 92) kept under a constant environment and feeding program in an ET center. Ultrasound guided transvaginal ovum pick-up following 48 h pre-treatment with FSH has been used for the IVF-IVC protocol. A total of 437 oocyte recovery sessions performed on 92 cows yielded 4145 oocytes, which were used in an IVF-IVC protocol. Using the conventional approach, 156 embryo collections on 49 cows yielded 1652 ova and embryos. All Quality 1 and 2 embryos were sexed by a PCR procedure, and embryos of the desired sex were transferred to synchronized recipients located at the center. The results obtained in the IVF protocol showed that 4 oocyte collections per cow performed within 60 d, yielded 38 oocytes, which resulted in 18.8 viable embryos, of which 7.05 were female. After transfer of the female embryos, an average of 3.8 recipients were pregnant at 60 d. One embryo collection under the conventional approach yielded an average of 1.2 female pregnancies, which was confirmed during the same 60-d time period. These results indicate that IVF procedures can effectively replace conventional embryo production methods when a predetermined number of pregnancies of known sex are needed within a short period of time.

Animals↗
PubMed1999

Job strain and pregnancy-induced hypertension.

In a case-control study we assessed whether exposure to high job strain during the first 20 weeks of pregnancy increases the risk of preeclampsia and gestational hypertension. Cases (128 with preeclampsia and 201 with gestational hypertension) and controls (N = 401) were primiparous women who had a paid occupation for at least 1 week during the first 20 weeks of their pregnancy and who delivered between 1984 and 1986 in 10 hospitals of Quebec, Canada. Based on their job title, we assigned women scores of psychological demand and decision latitude derived from the National Population Health Survey and classified these women as exposed to high (high demand, low latitude) versus low (low demand, high latitude) job strain. Women exposed to high job strain were more likely to develop preeclampsia [adjusted odds ratio (aOR) = 2.1; 95% confidence interval (CI) = 1.1-4.1] than women exposed to low job strain. The risk was quite similar for women exposed to a full-time, high strain job (> or =35 hours per week) (aOR = 2.0) than in a part-time, high strain job (aOR = 1.8). High job strain increased the risk of gestational hypertension slightly (aOR = 1.3; 95% CI = 0.8-2.2). These results indicate that women exposed to high job strain are at higher risk of developing preeclampsia and, to a lesser extent, gestational hypertension.

Adult↗
PubMed1999

Effects of an ergonomic training program on workers with video display units.

OBJECTIVES: This study evaluated the effect of an ergonomic training program on workstation changes and on the prevalence of musculoskeletal disorders among video display unit (VDU) users at a large university. METHODS: A pretest-posttest design with a reference group was used with random allocation of administrative and geographic units. In each group, the measurements involved direct observation of the workstations, a self-administered questionnaire, and a physical examination. The measurements were performed 2 weeks before and 6 months after the training in parallel in both groups. The study population was composed of 627 workers (81% of those eligible). RESULTS: The prevalence of all 3 of the postural stressors evaluated decreased in the experimental group after the training. In the reference group, 2 of the 3 stressors decreased in frequency but to a less extent. Some of these beneficial changes were more frequent in workers under 40 years of age. The prevalence of musculoskeletal disorders decreased among the workers under 40 years of age in the experimental group, from 29% to 13% determined by questionnaire and from 19% to 3% determined by physical examination. In other groups, there was no significant change in the prevalence of musculoskeletal disorders. CONCLUSIONS: Improvements in postural stressors occurred more frequently in the experimental group, and these beneficial changes tended to be more frequent in workers under 40 years of age. Improvements in musculoskeletal disorders occurred in the experimental group among the workers under 40 years of age.

Adult↗
PubMed1998

The Job Content Questionnaire (JCQ): an instrument for internationally comparative assessments of psychosocial job characteristics.

Part I discusses the Job Content Questionnaire (JCQ), designed to measure scales assessing psychological demands, decision latitude, social support, physical demands, and job insecurity. Part II describes the reliability of the JCQ scales in a cross-national context using 10,288 men and 6,313 women from 6 studies conducted in 4 countries. Substantial similarity in means, standard deviations, and correlations among the scales, and in correlations between scales and demographic variables, is found for both men and women in all studies. Reliability is good for most scales. Results suggest that psychological job characteristics are more similar across national boundaries than across occupations.

Adult↗
PubMed1998

Job strain and ambulatory blood pressure among female white-collar workers.

OBJECTIVES: The association between job strain and ambulatory blood pressure was studied among female white-collar workers. METHODS: This cross-sectional investigation studied 210 women in high- or low-strain jobs randomly selected from 3183 women of all ages, employed as white-collar workers. The women wore an ambulatory blood pressure monitor for 24 hours during a workday. Mean blood pressures were calculated. Psychological demands and decisional latitude were measured twice (14 months before and 7 days before the blood pressure measurement) with 2 scales recommended by Karasek. RESULTS: Significant differences in blood pressure were found according to current job strain among the women holding a university degree. Their mean blood pressures during work were significantly higher [8.0 mm Hg (1.1 kPa) systolic and 6.4 mm Hg (0.8 kPa) diastolic blood pressure] in the high-strain group than in the low-strain group. Statistically significant elevations in blood pressure over the 24-hour period were also found for women with a university degree. Cumulative exposure to high strain over 14 months was also significantly associated with high systolic blood pressure at work, in the evening, and over a 24-hour period irrespective of other factors related to blood pressure. Among the women without a university degree, the blood pressure differences observed between the job strain groups were less than 1 mm Hg (0.1 kPa) and not statistically significant. CONCLUSIONS: These results provide support for the effect of job strain on ambulatory blood pressure only among female white-collar workers holding a university degree.

Adolescent↗
PubMed1998

[Internal consistency, factorial validity and discriminant validity of the French version of the psychological demands and decision latitude scales of the Karasek "Job Content Questionnaire"].

BACKGROUND: The job demands-control model developed by Karasek has greatly influenced research on psychosocial factors at work and health. Validity of the English version of the psychological demands and decision latitude scales is documented. Psychometric qualities of the French version are investigated here in a representative sample of the general population, including blue-collars and white-collars. METHODS: The French translation of the psychological demand and decision latitude scales was administered by interview in a representative sample of the Quebec working population (N = 1,110). Internal consistency and factorial validity of the instrument were studied among white-collars and blue-collars separately. Discriminant validity was assessed for the whole population. RESULTS: Cronbach alpha coefficients, varying between 0.68 and 0.85, support the internal consistency of the scales. Demographic distribution of the scales and intercorrelations were consistent with the English version. Results of the factor analysis were consistent with the two dimensions expected from the theory. Mean scale scores and variations in the prevalence of high psychological demands combined with low decision latitude by age, sex, education, and job category support the discriminant validity of the instrument. CONCLUSIONS: Results support internal consistency, factorial validity, and discriminant validity of the French version of the psychological demands and decision latitude scales of the Karasek "Job Content Questionnaire" for white-collars and for blue-collars of the general population.

Adolescent↗
PubMed1997

Co-localization of CD9 and GPIIb-IIIa (alpha IIb beta 3 integrin) on activated platelet pseudopods and alpha-granule membranes.

CD9 is a 24-kDa membrane glycoprotein expressed on the surface of human platelets and potentially involved in cellular activation and adhesion functions. This protein belongs to a recently delineated family of cell-surface antigens that span the membrane four times, called tetraspans, and found mainly in leucocytes and tumour cells. As a first approach to clarify the function of CD9, we used immunoelectron microscopy to determine the localization of this antigen in human platelets, and compared its distribution with that of the GPIIb-IIIa integrin, the platelet receptor for fibrinogen. Monoclonal antibodies against CD9 (MAb7) and GPIIb-IIIa (HP1-1D) coupled to colloidal gold of different sizes (5 and 15 nm) were incubated with intact platelets in suspension or on ultrathin sections of platelets embedded in LR white. CD9 was found in association with GPIIb-IIIa on the inner face of alpha-granule membranes. These two antigens also colocalized on pseudopods of activated platelets and in contact regions between adjacent platelets. CD63, another member of the tetraspan family, was absent from alpha-granules but was associated with lysosomal structures. Flow cytometric analysis of platelet CD9 with a series of monoclonal antibodies revealed an increased expression upon thrombin stimulation, confirming the presence of an intracellular granular pool. The observation that CD9 and GPIIb-IIIa are stored in the same intracellular structures and migrate to the same activation zones after platelet stimulation lends support to previous suggestions of a close association between CD9 and GPIIb-IIIa in human platelets and of a possible involvement of CD9 in adhesive functions of platelets.

Antigens, CD↗