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In recent years, infectious diseases, specifically those that are caused by pathogens, have seen a dramatic proliferation due to resistance to multiple antibiotics, opening the colony by opportunistic pathogens. Nanotechnology and tissue engineering have been applied in the development of new antimicrobial therapies, capable of fighting opportunistic infections. In the medical field, research on antimicrobial properties of metal oxide nanoparticles have emerged to find new antimicrobial agents as an alternative against resistant bacteria. The metal oxides, particularly those formed by transition metals are compounds with electronic properties, and most magnetic phenomena involve this type of oxides. Nanoparticlesbased metal oxide properties such as shape, size, roughness, zeta potential and their large surface area, make oxides ideal candidates to interact with bacteria and able to have an antimicrobial effectiveness. The aim of this chapter is to offer an updated panorama about the relationships between the use of metal oxide nanoparticles in the medical field, with an emphasis on their role as antimicrobial agents and the properties that influence their antimicrobial response. In addition, the mechanism of nano-antimicrobial action is described and the importance of using in vitro test methods, adopted by leading international regulatory agencies, that can be used to determine the antimicrobial activity of the metal oxide nanoparticles.

Oral lesions (OL) have an important prognostic value for HIV/AIDS patients. However, the behavior of OL in HIV/AIDS patients undergoing highly active antiretroviral therapy including efavirenz (HAART/EFV) has not been documented. Our objective was to establish the prevalence of OL in HIV/AIDS patients undergoing HAART/EFV and to compare it with the prevalence of OL in patients undergoing antiretroviral therapy including a protease inhibitor (HAART/PI). Seventy-three HIV/AIDS patients undergoing antiretroviral treatment for at least for 6 months at "La Raza" Medical Center's Internal Medicine Unit (IMSS, Mexico City) were included. To detect OL, a detailed examination of oral soft tissues was performed in each patient. Patient records recorded gender, seropositivity time, route of contagion, antiretroviral therapy type and duration, CD4 lymphocyte count/ml, and viral load. Two groups were formed: 38 patients receiving HAART/EFV [two nucleoside analogue reverse transcriptase inhibitors (NARTI) plus efavirenz] and 35 patients receiving HAART/PI (two NARTIs plus one PI). OL prevalence was established in each study group. The Chi-square test was applied (p < 0.05(IC95%)). OL prevalence in the HAART/EFV group (32%) was lower (p < 0.007) than in the HAART/PI group (63%). Candidosis was the most prevalent OL in both groups. Herpes labialis, HIV-associated necrotizing periodontitis, xerostomia, hairy leukoplakia, and nonspecific oral sores were identified. The highest prevalence for all OL was found in the HAART/PI group. These findings suggest that HIV/AIDS patients undergoing HAART/EFV show a lower prevalence of oral lesions than patients undergoing HAART/PI.

The PE_PGRS33 protein is a member of the PE family, which encompasses the PE and the PE_PGRS subfamilies. Among PE_PGRS’s, this protein is one of the most studied antigens and its immunomodulatory properties are influence by both PE and PGRS domains. However, the contribution of these domains to the host immune recognition of the PE_PGRS33 protein and their potential role in latent tuberculosis infection in humans is still unknown. In this study, the immunogenic properties of the complete PE_PGRS33 protein and each domain separately were evaluated in BALB/c mice and latent tuberculosis infected (LTBI) humans. In mice, PE_PGRS33 and its domains induced similar antibody production and secretion of IFN-γ. PE_PGRS33 and the PE domain stimulated higher CD4+ and CD8+ T-cell proliferation compared to the PGRS domain. This demonstrated that the principal difference in the immune recognition of the domains is the higher activation of T-cell subpopulations involved in the control of tuberculosis. In humans, the secretion of IFN-γ in response to PE_PGRS33 was detected in both LTBI and in non-infected vaccinated individuals. The same was observed for antibody response, which targets epitopes located in the PGRS domain but not in the PE domain. These observations suggest that T and B cell responses to PE_PGRS33 are induced by BCG vaccination and can be maintained for many years in non-infected individuals. This also indicates that the IFN-γ response detected might not be associated with latent tuberculosis infection. These results contribute to the elucidation of the role of the PE_PGRS33 protein and its PE and PGRS domains in the immune response against Mycobacterium tuberculosis.

Most preventable adverse events during the dental health care are produced by a relatively small number of causes. Therefore, a few basic safety procedures can reduce significantly these preventable adverse events.

In addition to the initial caries experience, tooth morphology and Snyder test proved to be useful predictors for caries. These three risk markers may be particularly useful in targeting caries prevention efforts in developing countries.

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