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Biomedical subjects

M J Durand

Publications and source records attributed to M J Durand.

10 recordsLinked to original sources

Workplace interventions for workers with musculoskeletal disabilities: a descriptive review of content.

BACKGROUND: Despite the convergence of scientific data to the effect that interventions in the workplace promote a healthy return to work, the interventions carried out in the real work environment appear to be very heterogeneous and ill-defined. OBJECTIVE: The goal of this review is to identify the different objectives pursued through the workplace interventions carried out in the context of a rehabilitation program, and to describe the activities involved. METHODS: A descriptive review of the literature, including various research designs, was carried out. RESULTS: This review reveals great heterogeneity in the content of interventions offered in the workplace to workers with musculoskeletal disabilities. The objectives of workplace interventions may range from gathering information in order to reproduce work demands in a clinical setting, to gradually exposing workers to the demands of the real work environment, or permanently reducing the demands of the work situation. A descriptive analysis of the literature also brings to light the diversity of actions carried out, human resources used, and workplace environments involved, while highlighting the few documented process outcome evaluations that have been done of workplace interventions. CONCLUSION: It is recommended that in future research in this area, efforts be made to better describe the components of the interventions, to develop process outcomes representing the multidimensional results obtained in the workplace, and to differentiate between temporary and permanent modifications made to the work situation.

Ergonomics↗

Measurement properties of a new quality of life measure for patients with work disability associated with musculoskeletal pain.

INTRODUCTION: The Quality of Life Systemic Inventory (QLSI) measures patients' goal attainment based on the system control theory. It quantifies the perceived impact of the disorder and the gap between the present and aspired states. PURPOSE: To evaluate concurrent validity and responsiveness of the QLSI among workers on sick leave due to musculoskeletal disorders (MSDs). METHODS: Participants (10 women; 29 men) were recruited at a work rehabilitation centre and had more than 4 weeks of absence from work due to MSDs compensated by the Workers' Compensation Board. Concurrent validity and external responsiveness were based on baseline and post-treatment measures of external criteria. Criteria and related instruments were the following: perception of disability (Roland-Morris Disability Questionnaire); health-related quality of life (SF-12); stress (Psychological Stress Measure) and distress (Psychological Distress Index). RESULTS: Regression analyses revealed significant correlations between QLSI scores and the Psychological Distress Index (r2 = .11 to .19 and .66; p < .001), with either the SF-12 mental component scale (r2 = .18 and .11; p < .01) or the Roland-Morris Disability Questionnaire (r2 = .04 and .10; p < .05). All measures showed highly significant change over time. CONCLUSION: Results support the concurrent validity and responsiveness of the QLSI, with an MSD population. SIGNIFICANCE: This instrument could serve in future research as an outcome measurement instrument in the evaluation of more long-term effects of rehabilitation programs.

Adolescent↗

Development of a biosensor for on-line detection of tributyltin with a recombinant bioluminescent Escherichia coli strain.

A biosensor was developed for the detection of tributyltin (TBT), using a bioluminescent recombinant Escherichia coli:: luxAB strain. Dedicated devices allowed the on-line measurement of bioluminescence, pH and dissolved oxygen values and the feed-back regulation of temperature. Bacterial physiology was monitored by the measurement of the cellular density, respiratory activity and the intracellular level of ATP, glucose and acetate levels. Our results showed that a synthetic glucose medium gave a better TBT detection limit than LB medium (respectively 0.02 micro M and 1.5 micro M TBT). High growth and dilution rates ( D=0.9 h(-1)) allowed maximum light emission from the bacterium. Moreover, simple atmospheric air bubbling was sufficient to provide oxygen for growth and the bioluminescence reaction. Real-time monitoring of bioluminescence after TBT induction occurred with continuous addition of decanal up to 300 micro M, which was not toxic throughout a 7-day experiment. The design of our biosensor and the optimization of the main parameters that influence microbial activity led to the capacity for the detection of TBT.

Biosensing Techniques↗

Alteration in methyl-methanesulfonate-induced poly(ADP-ribosyl)ation by 2-butoxyethanol in Syrian hamster embryo cells.

The effects of 2-butoxyethanol (2-BE) on poly(ADP-ribosyl)ation were studied in Syrian hamster embryo (SHE) cells by measuring the cellular concentrations of the polymer poly(ADP-ribose) (pADPr) and of NAD+, the substrate of poly(ADP-ribose) polymerase (PARP). As biotransformation pathways of ethylene glycol ethers involve NAD+-dehydrogenases, it was hypothesized that 2-BE could reduce poly(ADP-ribosyl)ation by consuming NAD+. As a result DNA repair could be altered, which would explain that 2-BE had been shown to potentiate the effects of clastogenic substances such as methyl-methanesulfonate (MMS). In this study, the effects of 2-BE on MMS-induced pADPr metabolism were analyzed. The results indicated that: (i) 2-BE (5 mM) by itself did not influence significantly pADPr or NAD+ levels. (ii) 2-BE inhibited pADPr synthesis in MMS (0.2 mM)-pretreated cells, without any change in NAD+ concentrations. (iii) MMS treatment, which rapidly increased pADPr levels, also affected the poly(ADP-ribosyl)ation system as a secondary effect by damaging cell structures. Membrane permeabilization, which occurred at concentrations >1 mM MMS, led to a dramatic leakage of cellular NAD+ resulting in a strong reduction in pADPr levels. (iv) A bleomycin pulse (100 microM) applied after MMS and/or 2-BE treatment confirmed that 2-BE reduced poly(ADP-ribosyl)ation capacities of MMS-treated cells, though the glycol ether had no effect alone. This study confirmed that the inhibition of pADPr synthesis could be responsible for the synergistic effects of 2-BE with genotoxic substances. The mechanism of this inhibition cannot be explained by a lack of NAD+ at the concentrations of 2-BE tested.

Animals↗

Comparative effects of clofibrate and methyl clofenapate on morphological transformation and intercellular communication of Syrian hamster embryo cells.

The Syrian hamster embryo (SHE) cell system was used to evaluate the ability of two hepatocarcinogenic structurally related peroxisome proliferators (PPs) to induce morphological transformation (MT) of SHE colonies and to inhibit gap junctional intercellular communication (GJIC). Clofibrate and methyl clofenapate (MCP), which was shown to be a more active PP and a more potent carcinogen in vivo than clofibrate, were compared. MCP appeared slightly more active in vitro than clofibrate in affecting MT and GJIC of SHE cells. The morphological transformation of SHE colonies was induced by 50 microM MCP, against 100 microM clofibrate. Moreover, 50 microM MCP potentiated the transforming effects of both benzo[a]pyrene and 12-O-tetradecanoylphorbol-13-acetate. The inhibition of GJIC, measured by transfer of lucifer yellow, was transient and occurred at concentrations inducing morphological transformation. MCP inhibited dye transfer at 50 microM and the inhibition lasted up to 24 h at 100 microM. Inhibition of communication lasted only 4 h with clofibrate and occurred at a higher concentration (175 microM). This study showed that both the SHE cell transformation and dye transfer assays were able to display the different activities of the two PPs, even though the difference in potency observed was smaller than in vivo. It also revealed interactions between non-genotoxic carcinogens and the ability of the SHE cell transformation assay to detect these combined effects.

Animals↗

Correlating increased ocular and systemic blood pressures with neuroretinal function.

BACKGROUND: The microgravity environment of spaceflights alters the systemic circulation, decreasing the peripheral resistance, while increasing the heart rate and systemic blood pressure. HYPOTHESIS: Body orientation simulating fluid shifts associated with microgravity during spaceflights affects the neural retinal function. METHODS: Fifteen healthy adults between 18 and 26 yr of age participated in this study. Scotopic flash electroretinograms and oscillatory potentials were compared for: 1) baseline, wherein subjects were declined 30 degrees from vertical; and 2) for microgravity simulation where subjects were in a 7 degrees head down tilt for 90 min. RESULTS: Group averaged implicit times for the ERG b-wave, as well as OP3, OP4 and OP5 were prolonged after microgravity simulation, and the group averaged OP index was reduced. CONCLUSIONS: The results suggest that microgravity of relatively short duration may cause retinal ischemia manifest as neuroretinal dysfunction with yet undetermined effects on visual and overall performance.

Adolescent↗

Preparation of compound-specific and group-specific antibodies to 7-methylguanine and related 7-alkylguanines and their use in immunoaffinity purification.

The preparation and characteristics of compound-specific and group-specific antibodies against 7-alkylguanines (7-alkGua) are described. A compound-specific antibody against 7-methylguanine was prepared using a hapten bound to carrier protein through the N2 position. In a competitive enzyme-linked immunosorbent assay (ELISA) 7-methylguanine (7-MeGua) showed 50% inhibition (I50%) at 10 pmol/well at room temperature, but the inhibition was found to be 40 times better at 4 degrees C (I50% at 250 fmol/well). When the antibody was bound to protein A-Sepharose CL4B 7-MeGua was retained in immunoaffinity columns. A group-specific antibody to 7-alkGua was prepared using 7-(2-carboxyethyl)guanine (7-CEGua) bound to carrier protein via the carboxyl group. In a competitive ELISA, this antibody cross-reacted well with 7-CEGua, 7-ethylguanine (7-EtGua), 7-(2-hydroxyethyl)guanine (7-HOEtGua) and 7-(2',3'-dihydroxy)-propylguanine (7-DHPGua) and some inhibition was seen with 7-MeGua. Immunoaffinity columns prepared from this antibody retained a number of 7-alkGua of diverse structure. 7-EtGua in calf thymus DNA treated with diethylsulphate and ethylnitrosourea was isolated by immunoaffinity purification and quantified by HPLC-fluorescence. These results illustrate the potential of immunoaffinity purification for both individual DNA adducts and groups of adducts.

Alkylating Agents↗

Fluorescent postlabelling of modified DNA bases.

Postlabelling of modified DNA bases by methods other than the 32P method has attracted little attention to date. Three approaches using fluorescence have been made: (a) detection of a characteristic adduct-DNA functionality, e.g. reaction of cis-vicinal diols of PAH-DNA adducts with a boronate-containing fluorescent molecule; (b) reaction of modified nucleotides with a reactive fluorescent molecule, e.g. detection of 8-HOdG-5'-monophosphate by reaction with dansyl chloride; (c) reaction of modified DNA bases with reagents giving fluorescent products, e.g. derivatization of 7-MeGua with phenylmalondialdehyde (PhMal). Recent results in developing the latter approach are described. Reaction of a series of 7-alkylguanines, including 7-methyl-, 7-ethyl-, 7-(2-hydroxyethyl)-, 7-carboxymethyl-, 7-(2-carboxyethyl)- and 7-(2,3-dihydroxypropyl)-guanine, with PhMal gave fluorescent products showing similar spectral properties. The detection limit for fluorescence detection following reverse-phase HPLC separation was typically less than 1 pmol injected. In order to improve the sample clean-up before analysis, an antiserum has been prepared against the fluorescent derivative of 7-(2-carboxyethyl)guanine bound to carrier protein via the carboxyl group. The resulting antiserum cross-reacted with a number of PhMal derivatives.

DNA↗

Effects of TENS and topical skin anesthesia on soleus H-reflex and the concomitant influence of skin/muscle temperature.

The purpose of this study was to determine, in ten healthy subjects, the extent of soleus motoneuronal excitability during conditions of increased (transcutaneous electrical nerve stimulation [TENS]), decreased (Xylocaine [lidocaine]a anaesthesia) and normal (placebo anaesthesia) cutaneous inputs. Increased cutaneous activity was evoked using a TENS unit, with the two pairs of electrodes placed respectively over the Achilles (S2 dermatome) and tibialis anterior (L5 dermatome) tendons. Experimental and placebo topical anaesthesia were obtained after rubbing Xylocaine (5%) and Vaselineb ointment, respectively, on the skin surface overlying the Achilles tendon. Sets of ten H-responses (Hmax/2) were evoked at a frequency of 1 shock/30s and averaged at regular time intervals before, during and after the testing conditions. The results showed a gradual increase (up to 40% after 20 minutes) of H-reflex amplitude during TENS regardless of whether it was applied on the L5 or S2 dermatome. Furthermore, placebo anesthesia (Vaseline) caused the same gradual facilitatory response (up to 100% after 50 minutes) as that obtained during Xylocaine anaesthesia. Power spectral analysis of the H-responses obtained over time showed that the increase in the peak-to-peak H-response value was accompanied by a shift of the spectral content toward low frequencies. This shift occurred concomitantly with a cooling of the skin overlying the soleus muscle.

Administration, Topical↗