RESUMO
Panton-Valentine leucocidin arises from the combination of one S component (LukS-PV) with one F component (LukF-PV), whereas gamma-haemolysin comprises two S components (HlgA and HlgC) with one F component HlgB. The intravitreal injection of rabbit eye with the six combinations (S + F) of channel-forming leucotoxins produced by Staphylococcus aureus ATCC 49775 induced acute inflammatory reactions depending on time and doses of toxins. These reactions involved posterior chamber as well as anterior chamber and conjunctiva, eyelids and annexes. Histological examination confirmed the involvement of eye tissues and the disruption of the retinal barrier. The lesions began only 4 h after injections and persisted for at least 5 days. Clinical and biological effects of each leucotoxin were modulated by the speed of onset and intensity of inflammation and necrosis, leading to a functional classification according to the severity of the lesions (HlgA + LukF-PV > HlgA + HlgB > or = LukS-PV + HlgB > or = LukS-PV + LukF-PV > HlgC + HlgB > or = HlgC + LukF-PV). Moreover, N-acetyl beta-D glucosaminidase assays on crude extracts of vitreous revealed granules and granule secretions from polymorphonuclear cells with levels according the above classification. These results show that channel-forming leucotoxins have a very significant inflammatory activity. As most S. aureus strains produce two or even six leucotoxins depending on the production of Panton-Valentine leucocidin, these compounds could be considered to be virulence factors.
Assuntos
Toxinas Bacterianas/toxicidade , Exotoxinas/toxicidade , Olho/efeitos dos fármacos , Inflamação/induzido quimicamente , Staphylococcus aureus , Acetilglucosaminidase/biossíntese , Animais , Proteínas de Bactérias , Relação Dose-Resposta a Droga , Exotoxinas/classificação , Olho/enzimologia , Olho/patologia , Proteínas Hemolisinas/toxicidade , Leucocidinas/toxicidade , Coelhos , Fatores de TempoRESUMO
To examine previous work carried out at a single center, i.e., France, on the pathologic features of chronic pancreatitis and to examine geographic differences, 359 cases of chronic pancreatitis from five centers were studied pathologically and the results analyzed according to appropriate statistical methods. It was found that it was easy to separate chronic calcifying pancreatitis from obstructive pancreatitis occurring distal to obstruction to the pancreatic duct by pathological means. On the other hand, geographic differences between France, Italy, Brazil, and South Africa, although present, were not sufficient for identification of a specific profile for each of the countries studied, and it was found that the minor differences were probably dependent on environmental rather than racial factors.