Repeated survey on changes in musculoskeletal complaints relative to age and work demands.

OBJECTIVES: To examine changes in musculoskeletal complaints over four years in groups of employees relative to age and work demands. METHODS: Repeated questionnaire data of male employees in heavy physical work (exposed group, n = 7324) and mental work (control group, n = 4686), stratified for age (20-9, 30-9, 40-9, 50-9), were analysed. For each employee, data on the occurrence of musculoskeletal complaints from two surveys with a mean interval of around four years were available. Changes in prevalences over the follow up interval were analysed. Proportions of new, recovered, and chronic cases as well as those free of complaints at both surveys were studied. RESULTS: For most complaints, there were significantly greater increases in prevalences in the exposed group compared with the control group over the follow up interval particularly within the group aged 40-9 for back, neck, and several sites of the upper and lower limbs. The 20-9 year age group also had significantly greater changes for several musculoskeletal complaints. Within the oldest age group (50-9) exposure to heavy physical work demands only affected changes in prevalences of neck and upper arm complaints. After four years in the cohort free of complaints at the start of the follow up the group aged 40-9 had the highest prevalence of complaints of the back, neck, and the upper and lower limbs. CONCLUSIONS: Middle aged and younger employees develop musculoskeletal complaints as a result of exposure to heavy physical work. In the oldest age group health related selection seems to mask the occupational health risks under study. To prevent the expected increase in musculoskeletal disorders and related work disability in our aging workforce, preventive measures should be taken at all stages of a working life.     

Regulation of fibroblast-induced collagen gel contraction by interleukin-1β

Fibroblasts incorporated within collagen gels induce a cell-mediated contraction of the gel to form a three-dimensional, tissue-like structure by a mechanism thought to mimic wound contraction in vivo . In this study a gel contraction model was used to investigate the ability of fibroblasts derived from adult gingiva, adult skin and fetal skin to organise a collagen matrix. In addition the effects of interleukin-1β (IL-1β) on the contraction process was also investigated. Over the concentration range 5-50 U/ml, IL-1β induced a statistically significant inhibition of gel contraction in all fibroblast cell types ( P <0.05), although fetal fibroblasts appeared least responsive and gingival fibroblasts most responsive to the inhibitory effects of this cytokine. Comparison of gel contraction by the different fibroblast strains indicated that fetal and gingival fibroblasts shared similar contraction kinetics. For the adult skin fibroblasts, three of five strains studied showed significantly diminished levels of gel contraction compared to fetal and gingival cells. This apparent difference in fibroblast phenotype may, at least in part, explain the fetal-like wound healing pattern seen in the oral mucosa.     

Evidence that the Receptor for Soluble CD14:LPS Complexes may not be the Putative Signal-Transducing Molecule Associated with Membrane-Bound CD14

Membrane-bound CD14 acts as a receptor for lipopolysaccharide (LPS) on monocytes/macrophages and neutrophils. Studies have suggested that the activation of monocytes/macrophages by the binding of LPS to membrane-bound CD14 may require the association of a signal-transducing molecule with membrane-bound CD14. The observation that non-CD14 expressing cells, such as endothelial cells, can nevertheless be activated by a complex of LPS and a soluble form of CD14 (sCD14) suggests that the receptor for this complex may be identical to the signal transducing molecule associated with membrane-bound CD14. The studies described show that two CD14-specific MoAb are able to block the LPS-induced activation of endothelial cells but do not affect the response of monocytes to LPS. This suggests that the interaction of the sCD14:LPS complex with endothelial cells is distinct from the interaction of membrane-bound CD14 with its putative signal-transducing molecule.     

Co-localization of vasoactive intestinal polypeptide, γ-aminobutyric acid and choline acetyltransferase in neocortical interneurons of the adult rat

Interneurons immunoreactive for vasoactive intestinal polypeptide (VIP) are integral elements of columnar organization patterns in the rat cerebral cortex. By application of the sensitive mirror technique, the co-localization of VIP with the classical inhibitory neurotransmitter γ-aminobutyric acid (GABA) and the acetylcholine-synthesizing enzyme, choline acetyltransferase (ChAT), was investigated in neocortical neurons. Furthermore, the frequency of co-localization of ChAT with GABA was determined. In a sample of 118 VIP-immunoreactive neurons, mostly from the primary somatosensory cortex, it was demonstrated that virtually all of them reveal immunoreactivity for GABA and, therefore, are to be GABAergic. Moreover, 34% of mostly bipolar, VIP-positive neurons contained ChAT and are, thus, supposedly cholinergic as well. Co-localization of VIP and ChAT varied according to cortical laminae. Finally, 88% of a total of 60 ChAT-immunoreactive neurons were also immunostained for GABA. It is concluded that almost all VIP-immunoreactive neurons and most of the cholinergic neurons in rat neocortex represent partly overlapping subpopulations of inhibitory interneurons utilizing GABA.