PubMed Health⌕ Search

Biomedical subjects

C Brisson

Publications and source records attributed to C Brisson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Heterogeneous regulation of constitutive thrombomodulin or inducible tissue-factor activities on the surface of human saphenous-vein endothelial cells in culture following stimulation by interleukin-1, tumour necrosis factor, thrombin or phorbol ester.

Thrombomodulin and tissue-factor activities were measured on the surface of confluent human saphenous-vein endothelial cells (HSVEC) cultivated in 96-multiwell plates. Thrombomodulin activity was measured in the presence of purified human thrombin (2.2 nM) and protein C (65 nM). Tissue-factor activity was measured with purified human Factor VII (5 nM) and Factor X (400 nM). Generated activated protein C and Factor Xa released in the supernatant were assayed with chromogenic substrates. Resting cells exhibited significant thrombomodulin activity, but no detectable tissue-factor activity. After 4 h of preincubation with tumour necrosis factor (TNF, 22-2200 pM), interleukin-1 (IL-1, 5.7-570 nM) or phorbol myristate acetate (PMA, 1.61-161 nM) there was an increase in tissue-factor activity and a concomitant decrease in thrombomodulin activity. However, the extent of both responses varied according to the nature of the stimulus. Thrombin (0.44-44 nM) also induced an increase in tissue-factor activity, but had no effect on thrombomodulin activity. Kinetic studies showed that for all stimuli the increase in tissue factor was transient, reaching a maximum after 4-8 h of preincubation with the stimulating agent and returning to normal values after 24 h. IL-1 and TNF induced a time-dependent decrease in thrombomodulin, by respectively 47% and 67% of control values after 24 h. However, PMA induced only a transient down-regulation of thrombomodulin, full activity being recovered after 18 h. Hence this simultaneous assay system, using intact HSVEC and purified human coagulation factors, enabled us to observe that the regulation of thrombin generation could be diversely affected by various substances known to stimulate the endothelium. This suggests that the simultaneous and opposite modulation of these proteins does not represent an unified response of the endothelial cells to procoagulant stimuli. These results also confirm the absence of effect of thrombin on the expression of thrombomodulin on the cell surface.

Cell Membrane↗
PubMed1991

Validity of occupational histories obtained by interview with female workers.

This study measured the validity of work histories obtained by interview with 84 female workers and examined specific factors which influence such validity. This is the first validation of work histories collected by interviews with women. The validity of each interview was assessed over a period of 29 years, from 1955 to 1983. The information provided by the worker was compared annually to job information registered in public and union records. On the average, interviews yielded the correct information (either employer's name or nonworking year) for 81% of the person years of these subjects. However, there was a time effect; the average validity score for recent employment (1972-1983) was 89%, while that for employment in the more distant past (1955-1971) was 74%. Furthermore, workers who had fewer jobs, had longer durations of employment, and were non-French speaking had higher validity scores. Most of these findings are consistent with previous studies conducted among male respondents.

Employment↗
PubMed1991

Ultrastructural similarities between epidermal Langerhans cell Birbeck granules and the surface-connected canalicular system of EDTA-treated human blood platelets.

Birbeck granules characterize under the electron microscope epidermal Langerhans cells. These distinctive pentalaminar organelles are indeed not detectable in the possible precursors of human Langerhans cells and tend to disappear in cultured human Langerhans cells. The mechanisms that lead to the appearance of Birbeck granules in epidermal Langerhans cells and to their later disappearance still remain unknown. In the present study we show that the more or less dilated elements of the surface-connected canalicular system of human blood platelets collapse after EDTA treatment. Made up of two parallel limiting membrane and central irregular striated density, these elements show great ultrastructural similarities with the Birbeck granules of human epidermal Langerhans cells. These platelet morphologic changes i) are directly dependent on the EDTA-induced dissociation of the glycoprotein GP IIb-IIIa, the platelet-specific calcium-dependent heterodimer complex, member of the beta 3 integrin subfamily (alpha IIb beta 3) and ii) apparently result from a cross-linking of the dissociated glycoproteins. These findings lead us to propose that in the same manner cells of the Langerhans lineage, on reaching the epidermis, will find themselves in contact with an epidermal specific ligand. Interactions between this epidermal ligand and Langerhans cell receptors could then induce, all along the circuit taken by the ligand-receptor complexes, morphologic modifications, i.e., appearance of structures of Birbeck granule type.

Blood Platelets↗
PubMed1991

Endothelial cell seeding: coating Dacron and expanded polytetrafluoroethylene vascular grafts with a biological glue allows adhesion and growth of human saphenous vein endothelial cells.

The establishment of an endothelial lining on vascular grafts to obtain a highly thromboresistant surface in a clinical situation requires optimization of cell collection, quality, adhesion and growth. We have studied the conditions for collection, seeding and growth of human saphenous vein endothelial cells (HSVEC), on Dacron or Gore-Tex expanded polytetrafluoroethylene (PTFE) vascular grafts. Carefully handled veins, as opposed to veins obtained using the usual procedures for coronary bypass graft preparation, yielded a higher rate of successful culture (94% vs 43%) and reached confluence in primary culture sooner (9.4 +/- 3 days vs 13.4 +/- 4.5 days). HSVEC were seeded at a density of 6 x 10(3) cells/cm2 on graft fragments coated with fibronectin (FN) or Transglutine (TGL), a biological glue. There was no HSVEC adhesion on Dacron or PTFE without protein pretreatment of the artificial surface. FN improved HSVEC adhesion but there was no cell growth. Adhesion, doubling time and cell density at confluence on PTFE pretreated with TGL were similar to those on conventional tissue culture polystyrene (TCP) pretreated with TGL or FN. HSVEC adhesion on Dacron pretreated with TGL was lower than on TCP pretreated with TGL; the doubling time was similar but the density at confluence was 40% lower. We conclude that pretreatment of vascular grafts with TGL, besides being an alternative to preclotting of the Dacron graft, allows adhesion and growth to confluence of HSVEC on these surfaces.

Blood Vessel Prosthesis↗
PubMed1990

Modulation by cytokines of leukocyte-endothelial cell interactions. Implications for thrombosis.

Endothelial cells play an important role in the regulation of thrombosis. Normal resting (i.e. unstimulated) endothelial cells exhibit antithrombotic activity. This property is due to an active participation of endothelial cells in the inhibition of platelet adhesion and aggregation, in the inhibition of thrombin generation, in the direct inactivation of thrombin, and in clot lysis through the fibrinolytic system. When endothelial cells are stimulated by cytokines such as tumor necrosis factor (TNF) or interleukin 1 (IL-1), they may switch to an active procoagulant state. On the one hand, thrombin generation can be regulated on the endothelial cell surface by thrombomodulin, which allows the activation by thrombin of protein C which subsequently acquires and expresses potent anticoagulant properties. On the other hand, after activation, the same endothelial cell can express tissue factor on its surface, which will lead to the triggering of the coagulation cascade resulting in the generation of thrombin. TNF has been shown both to induce tissue factor gene expression and to suppress transcription of the thrombomodulin gene in endothelial cells. Many cytokines induce tissue factor gene expression and procoagulant activity in the monocyte/macrophage lineage; they also stimulate adhesion of leukocytes to endothelial cells. Cytokines such as IL-1 or TNF can thus be characterized as important intercellular messengers during the onset of coagulation. The role of these compounds can be schematized as: 1) agents of the stimulation of endothelial cells by leukocytes, 2) agents of stimulation of leukocytes by endothelial cells, 3) localization of the coagulation response through the initiation of endothelial cell-leukocyte interactions. Pharmacological modulation of these responses is possible along two pathways: 1) inhibition of the activation of endothelial cells or leukocytes responsible for cytokine release, 2) inhibition of the cytokine-induced cellular activation responsible for potentiation of procoagulant activity.

Cytokines↗
PubMed1989

Piecework, repetitive work and medicine use in the clothing industry.

This study was designed to examine the potential effects of severe time constraints on workers' health. Medicine use is considered to be an indicator of non-specific morbidity that is worthy of interest in industrial health research when it is possible to compare workers who share the same culture and socio-economic characteristics, but are submitted to different work conditions. In the clothing industry, our hypotheses were that (1) piecework paid operators would have a higher percentage of medicine users than the hourly paid and (2) operators who did repetitive work would have a higher percentage of medicine users than those who did non-repetitive work. Women selected into the study were between the ages of 45 and 70, natives of Canada, spoke French and lived in the metropolitan region of Montreal. The occupational data came from the files of The Ladies' Clothing Joint Commission. They encompass the 30-year period 1956-85. Data on socio-economic characteristics, smoking status and medicine use of the 800 respondents were obtained by questionnaires administered by specially trained nurses. Among currently employed women, the probability of using stomach medication was higher for pieceworkers than among women who received an hourly wage: OR = 2.57 (1.19-3.96). The probability was also higher for women who did repetitive work than for women who did non-repetitive work: OR = 2.43 (1.26-3.60).

Aged↗
PubMed1989

Effect of duration of employment in piecework on severe disability among female garment workers.

This study measured the association between duration of employment in piecework and the prevalence of severe disability among 533 Quebec female garment workers who left employment between 1976 and 1985. Yearly information regarding occupational characteristics was available from a public agency for the 30-year period 1956-1985. Information on disability status was collected in a personal interview. Duration of employment in piecework was associated with the prevalence of severe disability. A multivariate analysis found that the association was independent of age, smoking habits, education, type of task and total length of employment. Workers who spent 5-9, 10-14, 15-19, and greater than or equal to 20 years in piecework had an increased prevalence of severe disability in comparison with the base-line category of 0-4 years. The adjusted risk ratios were 2.2 [95% confidence interval (95% CI) 1.0-4.6], 3.3 (95% CI 1.5-6.9), 3.6 (95% CI 1.5-8.4), and 2.3 (95% CI 0.8-6.6), respectively. The association was particularly strong for disability due to musculoskeletal problems and disability due to cardiovascular disorders although small numbers were involved.

Adult↗
PubMed1989

Disability among female garment workers. A comparison with a national sample.

An indicator of permanent disability was used to measure the chronic health problems associated with garment work. The study population comprised 800 female sewing-machine operators employed in the Quebec garment industry between 1976 and 1985. The workers were identified from public agency records. Their disability status was obtained in a personal interview. The disability prevalence of these workers was compared to national disability data of women employed in clerical work, services, and manufacturing industries. The garment workers who had left employment had an increased prevalence of severe disability (in comparison with that of workers who had left other types of employment) and an increased prevalence of moderate and slight disability. Currently employed garment workers had an increased prevalence of moderate and slight disability when compared with workers currently employed in other occupations. The risk ratios remained similarly elevated when the data were adjusted for age and smoking status.

Adult↗
PubMed1987

Is social class standardisation appropriate in occupational studies?

Social class standardisation has been proposed as a method for separating the effects of occupation and "social" or "lifestyle" factors in epidemiological studies, by comparing workers in a particular occupation with other workers in the same social class. The validity of this method rests upon two assumptions: (1) that social factors have the same effect in all occupational groups in the same social class, and (2) that other workers in the same social class as the workers being studied are free of occupational risk factors for the disease of interest. These assumptions will not always be satisfied. In particular, the effect of occupation will be underestimated when the comparison group also has job-related exposures which cause the disease under study. Thus, although adjustment for social class may minimise bias due to social factors, it may introduce bias due to unmeasured occupational factors. This difficulty may be magnified when occupational category is used as the measure of social class. Because of this potential bias, adjustment for social class should be done only after careful consideration of the exposures and disease involved and should be based on an appropriate definition of social class. Both crude and standardised results should be presented when such adjustments are made.

Data Collection↗
PubMed1985

[Organization of work and mental health : repetitive work under time constraint ps.].

This present article first of all examines a general model of research concerned with the relationship between characteristics of a work organization and breaches in the workers' health and their mental and physical welfare. Thereafter this model is used in areas of mental health to study the consequences of a work organization where repetitive tasks are achieved under time restriction. The question is drawn out, followed by the results and methodological limitations of the researches done in this area. Then, the author describes a frame of analysis which integrates the acquired knowledge and the areas of research to be developed.

English Abstract↗
PubMed1977

Effect of somatostatin on plasma C-peptide immunoreactivity in normal man.

The effect of somatostatin on plasma C-peptide immunoreactivity was studied in seven normal men following an intravenous 25 g glucose load. No elevation in plasma insulin was observed and similarly no rise in plasma C-peptide immunoreactivity occurred, indicating that somatostatin inhibits glucose-induced C-peptide release as well as insulin release.

Blood Glucose↗
PubMedDate not supplied

Work problems after breast cancer: an exploratory qualitative study.

People treated for cancer have reported a variety of problems at work. However, there is little data on work experience after breast cancer, particularly for women treated in recent years. This exploratory qualitative study was conducted among 13 breast cancer survivors who had paid employment at diagnosis, returned to work afterwards, and mentioned work-related problems to a clinic nurse or physician. Unstructured, thematic interviews were undertaken. Qualitative thematic content analysis was conducted to identify and group themes which emerged from participants' discourse. Women in various types of jobs reported experiencing job loss, demotion, unwanted changes in tasks, problems with the employer and co-workers, personal changes in attitudes to work and diminished physical capacity. These work problems also preoccupied people treated for cancer more than two decades ago. New areas of concern also emerged: possible positive and negative effects of learning (implicitly or explicitly) about the diagnosis while at work and lack of discussion with health professionals about work and return-to-work issues, suggesting that health professionals' behaviour may influence women's work experience right from diagnosis. The identification of these new problems and confirmation of previously reported ones underlines the pertinence of determining how important and widespread these problems are in women now being treated for breast cancer.

Adult↗
PubMedDate not supplied

Transition metal carbonyl labeling of proteins. A novel approach to a solid-phase two-site immunoassay using Fourier transform infrared spectroscopy.

Labeling of bovine serum albumin (BSA) and anti-human thyroid stimulating hormone (hTSH) monoclonal antibodies (mAbs) was performed using (N-succinimidyl 4-pentynoate)hexacarbonyldicobalt (NSCo2(CO)6). Conditions of coupling were different depending on the protein to be labeled, denaturation of the mAbs occuring with high percentages of organic solvent in the reaction mixture. The influence of reaction time and initial concentration of NSCo2(CO)6 was examined. They were both shown to affect the final coupling rate of the metal carbonyl probe. Preservation of the immunoreactivity toward 125I-hTSH was observed for five conjugates having different NSCo2(CO)6: mAb molar ratios when compared to unmodified and peroxidase-labeled mAbs. Finally, a preliminary study of the quantitative detection of the metal carbonyl mAbs on microtiter wells was achieved using Fourier transform infrared spectroscopy.

Animals↗
PubMedDate not supplied

Effect of family responsibilities and job strain on ambulatory blood pressure among white-collar women.

OBJECTIVE: This study was conducted to determine whether large family responsibilities and their combination with high job strain were associated with an increase in ambulatory blood pressure (BP) among white-collar women. METHODS: A cross-sectional study was conducted in a stratified random sample of 199 white-collar women with or without children who were employed full time in jobs involving high or low strain. These women were selected from a population of 3183 women of all ages, employed in eight organizations in Quebec City, Canada. Subjects wore an ambulatory BP monitor for 24 hours during a working day. Mean BPs were calculated. Different measures of family responsibilities were used, based on the number of children and their ages, and domestic work. Job strain was measured using the Job Content Questionnaire recommended by Karasek. RESULTS: Family responsibility measures were significantly related to diurnal BP among women holding a university degree (N=69). Indeed, women having large family responsibilities had increases in systolic and diastolic BPs of 2.7 to 5.7/1.8 to 4.0 mm Hg (p< or =.05). Among women holding a university degree, increases in diurnal systolic and diastolic BPs reached 8.1 to 10.9/5.5 to 7.1 mm Hg (p< or =.01) among women having both large family responsibilities and high job strain. These results were independent of confounders. There was no significant association among women without a university degree (N=130). CONCLUSIONS: Large family responsibilities were associated with significant increases in diurnal systolic and diastolic BPs among white-collar women holding a university degree. In these women, the combined exposure of large family responsibilities and high job strain tended to have a greater effect on BP than the exposure to only one of these factors.

Adolescent↗