Killing of schistosomula by taurine chloramine and taurine bromamine

Eosinophils generate hypochlorous acid when stimulated with opsonized particles. The hypochlorous acid can react with beta-amino acids such as taurine to produce chloramines with a long lifetime. In the presence of bromide, eosinophils generate hypobromous acid which can react with taurine to generate taurine bromamine. As taurine is abundantly present in leukocytes, eosinophils have the potential to generate taurine chloramine or taurine bromamine. With regard to the role of eosinophils in killing schistosomula, we have shown that both taurine chloramine and taurine bromamine in physiological concentrations are able to kill the schistosomula of Schistosoma mansoni.     

Procalcitonin''s amino-terminal cleavage peptide is a bone-cell mitogen.

The parafollicular-cell (C-cell) hormone calcitonin (CT) can preserve or even augment skeletal mass by inhibiting osteoclast-mediated bone resorption. The possibility of an additional anabolic skeletal influence has also been raised: C cells might, via CT or other secretory products, affect osteoblast-mediated bone formation. The 57-residue amino-terminal procalcitonin cleavage peptide, N-proCT, has recently been identified in human and rat C cells, where it is made and secreted in equimolar amounts with CT. The coelaboration of N-proCT and CT and N-proCT's sequence conservation during evolution prompted us to investigate the potential skeletal bioactivity of N-proCT. We found that synthetic human N-proCT, at nanomolar concentrations, stimulated proliferation of normal and neoplastic human osteoblasts. At maximally effective doses, human N-proCT caused more than a 100% increase above the control rate of DNA synthesis, an effect comparable to the maximal growth effect of insulin, a potent mitogen for osteoblasts. Human N-proCT exerted a similar maximal mitogenic effect in chicken osteoblast cultures but at 1000-fold greater concentrations than in human bone-cell cultures. The bone-cell action of N-proCT was potentiated with insulin with a greater than 200% increase in DNA synthesis at high insulin concentrations. In sharp contrast to these findings for N-proCT, the other bioactive C-cell peptides, CT and somatostatin, showed no mitogenic effects in human or chicken osteoblast cultures. Our results indicate that the action of N-proCT on cultured bone cells is separate from and potentiated by insulin, a known growth factor. Unlike insulin and related growth factors such as insulin-like growth factor I, N-proCT is not mitogenic in skin fibroblast cultures. We propose that N-proCT is a C-cell hormone that promotes bone formation via stimulatory actions on osteoblasts and preosteoblasts.     

Evaluation of beta-lactamase activity and microbial interference in treatment failures of acute streptococcal tonsillitis

Out of 169 patients with streptococcal tonsillitis treated with phenoxymethylpenicillin, 13 (8%) developed a new clinical infection with the same streptococcal strain within 2 weeks of completing the therapy (clinical treatment failure) and 24 (14%) were clinically healthy but harboured the same streptococcal strain after treatment (bacterial treatment failure). Patients with clinical treatment failure showed beta-lactamase activity in their saliva pellet significantly more often than patients with bacterial treatment failure, healed streptococcal tonsillitis or non-streptococcal tonsillitis as well as healthy controls. In an interference study, clinical treatment failures were compared with healthy streptococcal carriers, i.e. persons living in the same household and harbouring the same beta-streptococcal strain. 11/12 healthy carriers had alpha-streptococci with interfering activity against their own beta-streptococcal strain, while the corresponding figure for the clinical treatment failures was 2/13. Furthermore, 6/12 healthy carriers had beta-streptococci inhibiting their own alpha-strains, while the streptococci in 11/13 clinical treatment failures had this ability. The beta-lactamase activity and the interference between alpha- and beta-streptococci may be a contributory cause to treatment failure in streptococcal tonsillitis.     

Neuropsychological findings in children with Gilles de la Tourette syndrome

Eight children with the syndrome of Gilles de la Tourette underwent a neuropsychological assessment. The results were compared with those of eight children with proven lesions of the right cerebral hemisphere and with eight children with learning disabilities without neurological disturbances. Our findings do not support organicity or dysfunctions of the right hemisphere in children with Gilles de la Tourette syndrome.     

Induction of tumoricidal activity in isolated rat liver macrophages by liposomes containing recombinant rat gamma-interferon supplemented with lipopolysaccharide or muramyldipeptide

We examined whether the macrophages in the liver, Kupffer cells, could be activated to a tumoricidal state in a similar way as has been described for other macrophage types. Kupffer cells were isolated by centrifugal elutriation of pronase-treated rat livers. Incubation with highly purified recombinant rat gamma-interferon in combination with small amounts of lipopolysaccharide or muramyldipeptide resulted in highly cytotoxic macrophages, as measured against P815 tumor cells in an 18 h 51Cr-release assay. Incubation of Kupffer cells with the stimulators entrapped within liposomes, caused phagocytosis of the liposomes and subsequent activation to tumor cytotoxicity, provided that both rat gamma-interferon and subthreshold doses of either lipopolysaccharide or muramyldipeptide were encapsulated. The minimum amount of liposomal rat gamma-interferon that induced optimal activation was 0.5 U/ml, while 6 ng/ml of liposomal lipopolysaccharide or muramyldipeptide was required. Cytotoxicity of Kupffer cells activated in this way, persisted for at least 48 h. Since liposomes in circulation are readily cleared by the liver macrophages, these findings may have therapeutic implications.