Résumé
Objective To provide integral biological assessment on carbon fiber,aluminum alloy (6061)and stainless steel (05Cr17Ni4Cu4Nb)for external skeletal fixation.Methods According to biological evaluation criterion of medical devices, four tests in vitro and vivo were selected on the basis of the GB/T 14233.2—2005 and GB/T 16886 serial standards. The cytotoxicity test determined with MTT method. Acute general toxicity test, tests for irritation and delayed -type hypersensitivity were to evaluate biological safety by two leaching media of polar solvent (sodium chloride) and nonpolar solvent (cottonseed oil).Results The scaffold materials of external skeletal fixation had no cell toxicity in vitro.The three materials had none of acute general toxicity, skin irritation and sensitization in sodium chloride and cottonseed oil. Conclusion Carbon fiber,aluminum alloy (6061)and stainless steel (05Cr17Ni4Cu4Nb)are kinds of bone external scaffold materials with high biocompatibility and can be safely applied for clinical use.
Résumé
Visceral leishmaniasis (VL), also known as kala-azar, is an important public health problem. If not treated, virtually all clinically symptomatic patients die within months. The diagnosis is based on the Montenegro skin test (MST) and anti-Leishmania titers. Nevertheless, the time required for cured individuals living in a leishmaniasis-endemic area to present a positive skin test and negative anti-Leishmania serology is known. To determine the cellular and humoral immune response profile in relation to different times post-VL cure, a cross-sectional study was conducted on subjects from a kala-azar endemic area in Paço do Lumiar, MA, Brazil, on the basis of 1995-2005 notifications reported by the National Health Foundation/Regional Coordination of Maranhão. We visited cured individuals with a history of VL within the last 10 years. Seventy-four subjects (30 females) ranging in age from 1 to 44 years were included, all of them symptom free at the time of the study. A cellular immune response was observed in 73 (98.6 percent) subjects, whereas no significant antibody titers were detected by indirect immunofluorescence (IIF) in the sera of 69 (93.2 percent) cases. Ten years post-cure, 39 (52 percent) subjects had a positive MST and negative IIF reaction, while in one subject the skin and anti-Leishmania serology tests were negative. Two other subjects were positive in both tests 1 year after cure. These data suggest that a cellular immune response may still be present in subjects cured of VL regardless of post-cure time, and that the parasite persists in the host after clinical cure of the disease. This would explain the persistence of significant Leishmania sp antibody titers in some subjects after treatment.