Fear of aids: An assessment of knowledge and attitudes of medical,nursing, and medical technology students

The reluctance of students in health professions to care for AIDS patients is partially based on the perceived risk of transmission of HIV from patient contact. We hypothesize that fear of contagion is due to lack of knowledge and deep‐rooted attitudes and emotions existing even in areas of low HIV seroprevalence. We tested this hypothesis on medical, nursing, and medical technology students. Using a questionnaire that yielded four scales, results showed only 58% of students were knowledgeable, 81% were fearful of contagion, 57% were homophobic, and 8% had death anxiety. Lack of knowledge was correlated with fear of contagion (p < .05), whereas homophobia was weakly associated (p = .08). We conclude that this perceived risk of infection is a result of lack of knowledge, disbelief of the facts, and the interplay of personal values and emotions. Alternative educational methods are needed to increase students’ knowledge and to encourage students to examine their personal feelings and attitudes.     

Tridimensional ultrastructure and glycolipid pattern studies of Trypanosoma dionisii

Trypanosoma (Schizotrypanum) dionisii is a non-pathogenic bat trypanosome closely related to Trypanosoma cruzi, the etiological agent of Chaga's disease. Both kinetoplastids present similar morphological stages and are able to infect mammalian cells in culture. In the present study we examined 3D ultrastructure aspects of the two species by serial sectioning epimastigote and trypomastigote forms, and identified common carbohydrate epitopes expressed in T. dionisii, T. cruzi and Leishmania major. A major difference in 3D morphology was that T. dionisii epimastigote forms present larger multivesicular structures, restricted to the parasite posterior region. These structures could be related to T. cruzi reservosomes and are also rich in cruzipain, the major cysteine-proteinase of T. cruzi. We analyzed the reactivity of two monoclonal antibodies: MEST-1 directed to galactofuranose residues of glycolipids purified from Paracoccidioides brasiliensis, and BST-1 directed to glycolipids purified from T. cruzi epimastigotes. Both antibodies were reactive with T. dionisii epimastigotes by indirect immunofluorescense, but we noted differences in the location and intensity of the epitopes, when compared to T. cruzi. In summary, despite similar features in cellular structure and life cycle of T. dionisii and T. cruzi, we observed a unique morphological characteristic in T. dionisii that deserves to be explored.     

A role for heme oxygenase-1 in the immunosuppressive effect of adult rat and human mesenchymal stem cells

Mesenchymal stem cells (MSCs) display immunomodulatory properties mediated by various factors, including inducible nitric oxide synthase (iNOS). Since heme oxygenase-1 (HO-1) is a potent immunosuppressive enzyme, we tested the hypothesis that HO-1 could mediate the immunosuppressive effects of MSCs. We generated adult rat MSCs that inhibited T-cell proliferation in vitro. These MSCs expressed both HO-1 and iNOS. In vitro, whereas neither HO-1 nor iNOS inhibition alone could interfere with the immunosuppressive properties of rat MSCs, simultaneous inhibition of both enzymes restored T-cell proliferation. In vivo, injection of MSCs significantly delayed heart allograft rejection, and inhibition of either HO-1 or iNOS totally reversed the protective activity of MSCs, inducing rejection. Adult human MSCs also expressed HO-1; in these cells, HO-1 inhibition was sufficient to completely block their immunosuppressive capacity. In conclusion, we show, for the first time, that HO-1 mediates the immunosuppressive properties of rat and human MSCs.     

Functional amelioration of murine galactosialidosis by genetically modified bone marrow hematopoietic progenitor cells

Protective protein/cathepsin A (PPCA), a lysosomal carboxypeptidase, is deficient in the neurodegenerative lysosomal disorder galactosialidosis (GS). PPCA(-/-) mice display a disease course similar to that of severe human GS, resulting in nephropathy, ataxia, and premature death. Bone marrow transplantation (BMT) in mutant animals using transgenic BM overexpressing the corrective enzyme in either erythroid cells or monocytes/macrophages has proven effective for the improvement of the phenotype, and encouraged the use of genetically modified BM cells for ex vivo gene therapy of GS. Here, we established stable donor hematopoiesis in PPCA(-/-) mice that received hematopoietic progenitors transduced with a murine stem cell virus (MSCV)-based, bicistronic retroviral vector overexpressing PPCA and the green fluorescent protein (GFP) marker. We observed complete correction of the disease phenotype in the systemic organs up to 10 months after transplantation. PPCA(+) BM-derived cells were detected in all tissues, with the highest expression in liver, spleen, BM, thymus, and lung. In addition, a lysosomal immunostaining was seen in nonhematopoietic cells, indicating efficient uptake of the corrective protein by these cells and cross-correction. Expression in the brain occurred throughout the parenchyma but was mainly localized on perivascular areas. However, PPCA expression in the central nervous system was apparently sufficient to delay the onset of Purkinje cell degeneration and to correct the ataxia. The long-term expression and internalization of the PPCA by cells of systemic organs and the clear improvement of the neurologic phenotype support the use of this approach for the treatment of GS in humans. (Blood. 2002;99:3169-3178)