Infection control attitudes and perceptions among dental students in Latin America: implications for dental education.

UNLABELLED: Latin American dental schools are at diverse stages in the continuum of implementation of infection control (IC) programmes that comply with evidence-based recommendations. Poor IC training may result in low compliance and negative attitudes against patients infected with blood borne pathogens (BBP). OBJECTIVE: To evaluate students' knowledge on IC and attitudes toward occupational BBP risks, in six dental schools in Latin America. METHODS: This survey was administered to convenience samples of dental students at one school in Costa Rica; four schools in Mexico, and one in Venezuela. The questionnaire included Likert-type scale evaluations of agreement with statements. Study variables included knowledge about and confidence in recommended IC procedures, degree of concern about HIV and HBV transmission in dental settings, and attitudes toward patients infected with BBP. Possible associations between variables were analysed using Pearson's Chi square and Kruskal Wallis tests. RESULTS: Substantial numbers of students had incomplete knowledge and often lacked confidence on IC and procedures; believed that HIV and HBV could be transmitted during clinical procedures; felt worried about occupational exposure to BBP, and held prejudices towards HIV and HBV infected individuals. CONCLUSIONS: Educational efforts are needed to enhance IC teaching and compliance. Diverse educational resources and international networks for research collaboration are available from organisations specialised in IC, hopefully paving the way to harmonising regional standards.

Dendritic cell immunizations alone or combined with low doses of interleukin-2 induce specific immune responses in melanoma patients.

Dendritic cell (DC)-based therapy has proved to be effective in patients with a variety of malignancies. However, an optimal immunization protocol using DCs and the best means for delivering antigens has not yet been described. In this study, 20 patients with malignant melanoma in stages III or IV were vaccinated with autologous DCs pulsed with a melanoma cell lysate, alone (n = 13) or in combination with low doses of subcutaneous (s.c.) interleukin (IL)-2 injections (n = 7), to assess toxicity, immunological and clinical responses. Monocyte-derived DCs were morphological, phenotypic and functionally characterized in vitro. Peripheral blood mononuclear cells (PBMC), harvested from patients either prior to and after the treatment, were analysed using enzyme-linked immunosorbent spot (ELISPOT). After vaccination, 50% of the patients tested (seven of 13) from the first group and (three of seven) from the second, showed an increase in interferon (IFN)-gamma production in response to allogeneic melanoma cell lines but not to controls. Four of five tested human leucocyte antigen (HLA)-A2(+) patients with anti-melanoma activity also showed specific T cell responses against peptides derived from melanoma-associated antigens. Delayed type IV hypersensitivity reaction (DTH) against melanoma cell lysate was observed in six of 13 patients from the group treated with DC vaccines only and four of seven from the group treated with the combination of DCs and IL-2. Significant correlations were found between DTH-positive responses against tumour lysate and both disease stability and post-vaccination survival on the stage IV patients. There were no toxicities associated with the vaccines or evidence of autoimmunity including vitiligo. Furthermore, no significant enhancement was observed as a result of combining DC vaccination with IL-2. Our data suggest that autologous DCs pulsed with tumour lysate may provide a standardized and widely applicable source of melanoma specific antigens for clinical use. It is safe and causes no significant side effects and has been demonstrated to be partially efficient at triggering effective anti-melanoma immunity.

Avances en inmunoterapia celular contra el melanoma maligno / Advances in cellular immunotherapy for malignant melanoma

An alternative strategy for cancer treatment is the manipulation of the immune system, denominated cancer immunotherapy. The immunotherapeutical use of cells of the immune system, like dendritic cells (DC), is being explored in different clinical protocols. Recently, we finalized a clinical phase I protocol, for the treatment of malignant melanoma, using DCs loaded with tumor lysates. Our results indicate that the subcutaneous application of DCs do not produce adverse effects. We also observed an increase of tumor specific T lymphocytes precursors in the blood, associated to hypersensitivity reactions (DTH) in 60% of the treated patients. In most cases, an stability in the disease was observed, although without a significant association between vaccination and survival. Additionally, therapies based on Interleukin-2 (IL-2) have been used with relative success in the treatment of some kind of tumors since 1985. However, problems associated to the toxicity of IL-2 still restrict its massive use. Our direct experience with the use of IL-2, indicates that low doses and its subcutaneous application, maintains the beneficial effects for patients, eliminating the adverse effects. Based on the accumulated evidence during last the five years, we decided to implement an optimized clinical protocol, which alternatively combines dendritic cells vaccines with the use of low doses of IL-2 for the reinforcement of the immunological system.

[Is the epidemiological surveillance system of nosocomial infections recommended by the American CDC applicable in a Chilean hospital?]. / Es aplicable el sistema de vigilancia epidemiológica de las infecciones intrahospitalarias que recomienda el CDC-americano (sistema NNIS) en un hospital chileno?

BACKGROUND: The National Nosocomial Infections Surveillance System (NNIS system) is the method for surveying nosocomial infections used by the Centers for Disease Control (CDC). This strategy allows the comparison of different hospitals, using rate adjustments. In Chile, this system is not used. AIM: To report the application of this system in a tertiary reference hospital in Chile. MATERIALS AND METHODS: We performed a six months prospective cohort study. The active surveillance was carried out by using the intensive care unit and surgery components of the NNIS system. Tabulation and analysis of the data were done according to the NNIS system. In a parallel prevalence study, we determined the NNIS system sensitivity to detect nosocomial infections. RESULTS: A total of 492 patients were followed with a global nosocomial infection rate of 14%, for discharged patients. The calculated sensitivity and specificity of the system was 84.2 and 97% respectively. In the intensive care unit, 45 of 169 patients had nosocomial infections, with an adjusted rate of 2.8% for mean hospitalization time and severity of illness. In the cardiovascular and thoracic surgical units, 216 and 107 procedures were surveyed, respectively. The global rates of nosocomial infections were 7.4 and 7.5%, respectively. The adjusted rates according to risk factors were 0.9 and 2.3%, respectively. CONCLUSIONS: These data indicate that the surgical units had surgical site infections rates similar to those reported by the CDC. Nosocomial infections rates in Chile can be compared with rates observed in other countries. The epidemiological data collected can be useful to focus intervention or preventive strategies.

Gammapatias monoclonales. / Monoclonal gammapathies

Se analizan 112 casos de inmunoglobulinas monoclonales pesquisadas en un periodo de cuatro anos, en el Laboratorio de Inmunologia de la Universidad de Fisiopatologia Occidente, Facultad de Medicina, Universidad de Chile, en pacientes del Area de Salud Metropolitana Occidente. El estudio consiste en una evaluacion inmunologica, clinica, radiologica y de laboratorio bioquimico general. Se determina la distribucion diagnostica de las inmunoglobulinas monoclonales detectadas clasificandolas en gammapatias monoclonales de significado indeterminado y gammapatias monoclonales malignas. Se analiza la distribucion por sexo y edad en cada grupo. Por ultimo, se establece una relacion entre la clasificacion diagnostica y los niveles sericos de las inmunoglobulinas monoclonales