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Work-related low back pain is a major problem for both patients and employers. Although the cause of the pain is often unclear, patients failing to return to work within 3 to 6 months have a poor medical and economic prognoses. This article reviews issues relevant to the need for aggressive management of acute, work-related LBP cases.

Salmonella typhimurium and Escherichia coli K12 mutants of R chemotype, with varying contents of major proteins, were studied with respect to serum-mediated killing. The mutants demonstrated a different susceptibility to serum lytic action. These results were related to phospholipid and fatty acid content, as well as different physico-chemical surface properties, such as outer membrane fluidity. Tests were carried out on all parameters considered in the literature to demonstrate the resistance to complement. Our results showed that in sensitive strains such as Salmonella strains SH6261, SH6378, SH5551, SH6017 and E. coli PC0479 tests taken alone were not sufficient to explain the resistance to complement. Therefore, complement susceptibility is probably determined by many factors influencing the microheterogeneity of the membrane system.

Our study considered the possibility of modifying the functional response of human neutrophils, of mouse lymphocytes and macrophages treated with phospholipids having different polar groups, different isomerisms with saturated and unsaturated fatty acids from C12 to C20 carbon atoms. The results are as follows. a) Most of the phospholipids containing fatty acids from C12 to C20 cause inhibition of the blastogenic capacity of the polyclonal activators tested. b) The phospholipids tested cause a decrease in adherence of polymorphonuclear leukocytes with the exception of the phosphatidyl-choline containing saturated and unsaturated fatty acids. c) A decrease in polymorphonuclear leukocytes migrational capacity almost always occurs. d) The cells treated with L-phosphatidyl-ethanolamine having fatty acids from C14 to C17 show an increase in chemiluminescence; those treated with phosphatidyl-choline and L-phosphatidyl-glycerol show a decrease of the chemiluminescence; L-phosphatidic acid and L-phosphatidyl-ethanolamine having Microbial fatty acids (FAs) at C16 cause a decrease in the formation of phagolisosomes in the macrophages tested.

Mutants of Salmonella typhimurium, which contain different quantities of outer membrane proteins, show different susceptibility to phagocytosis. We correlate susceptibility to phagocytosis with molecular surface characteristics which are responsible for invasiveness and virulence of bacteria.

The outer membrane of Gram-negative bacteria contains some major proteins, called porins, with particular chemical and physical characteristics which reflect some specialized functions peculiar to the outer membrane. In recent years the biological properties of Salmonella typhimurium SH5014 porins have been the focus of our experimental studies. The aim of the present research was to make a comparative investigation of the biological activities of porins extracted from other microorganisms classified in the Enterobacteriaceae, together with a taxonomically different one, Eikenella corrodens frequently isolated from gum pockets of patients with periodontal disease. Porins from E. coli K12, Proteus mirabilis and Eikenella corrodens were extracted, purified and separated from LPS by means of phenol extraction. The purity of preparation was checked by sodium dodecyl sulphate polyacrylamide gel electrophoresis in slabs. We studied the interactions of these proteins with some cellular and humoral systems within the host. Mouse peritoneal macrophages in the presence of these proteins show morphological and functional modifications, depending upon the type of porins and the concentrations used. The ability of porins to interact with the complement system was investigated in vitro. A pool of sera from 20 blood donors served as a source of human complement. The results obtained with porins of various sources were shown comparatively.

The protein SV-IV, one of the major secretory proteins produced by the rat seminal vesicle epithelium, has been found to possess a marked ability to inhibit in vitro the phagocytic properties of activated peritoneal rat macrophages, by a mechanism that apparently involves phagocytes and target cells. Although SV-IV is a substrate for transglutaminase (TGase), an enzyme secreted by activated macrophages, TGase does not seem to play any significant role either in the binding of the protein to the cells participating in the phagocytic process or in the inhibition of macrophage phagocytosis by SV-IV. The significance of the findings in relation to the reproductive process and their possible clinical implications are discussed.