Photochemical outcomes triggered by gold shell-isolated nanorods on bioinspired nanoarchitectonics for bacterial membranes.

Boosted by the indiscriminate use of antibiotics, multidrug-resistance (MDR) demands new strategies to combat bacterial infections, such as photothermal therapy (PTT) based on plasmonic nanostructures. PTT efficiency relies on photoinduced damage caused to the bacterial machinery, for which nanostructure incorporation into the cell envelope is key. Herein, we shall unveil the binding and photochemical mechanisms of gold shell-isolated nanorods (AuSHINRs) on bioinspired bacterial membranes assembled as Langmuir and Langmuir-Schaefer (LS) monolayers of DOPE, Lysyl-PG, DOPG and CL. AuSHINRs incorporation expanded the isotherms, with stronger effect on the anionic DOPG and CL. Indeed, FTIR of LS films revealed more modifications for DOPG and CL owing to stronger attractive electrostatic interactions between anionic phosphates and the positively charged AuSHINRs, while electrostatic repulsions with the cationic ethanolamine (DOPE) and lysyl (Lysyl-PG) polar groups might have weakened their interactions with AuSHINRs. No statistical difference was observed in the surface area of irradiated DOPE and Lysyl-PG monolayers on AuSHINRs, which is evidence of the restricted nanostructures insertion. In contrast, irradiated DOPG monolayer on AuSHINRs decreased 4.0 % in surface area, while irradiated CL monolayer increased 3.7 %. Such results agree with oxidative reactions prompted by ROS generated by AuSHINRs photoactivation. The deepest AuSHINRs insertion into DOPG may have favored chain cleavage while hydroperoxidation is the mostly like outcome in CL, where AuSHINRs are surrounding the polar groups. Furthermore, preliminary experiments on Escherichia coli culture demonstrated that the electrostatic interactions with AuSHINRs do not inhibit bacterial growth, but the photoinduced effects are highly toxic, resulting in microbial inactivation.

Saccharomyces boulardii modulates oxidative stress and renin angiotensin system attenuating diabetes-induced liver injury in mice.

Type 1 diabetes (T1DM) is a chronic disease characterized by hyperglycemia due to a deficiency in endogenous insulin production, resulting from pancreatic beta cell death. Persistent hyperglycemia leads to enhanced oxidative stress and liver injury. Several studies have evaluated the anti-diabetic and protective effects of probiotic strains in animal models. In the present study, we investigated, through histopathological and biochemical analyses, the effects of eight weeks of administration of Saccharomyces boulardii (S. boulardii) yeast on the liver of streptozotocin (STZ) induced diabetic C57BL/6 mice. Our results demonstrated that S. boulardii attenuates hepatocytes hydropic degeneration and hepatic vessels congestion in STZ-induced diabetic mice. The treatment attenuated the oxidative stress in diabetic mice leading to a reduction of carbonylated protein concentration and increased activity of antioxidant enzymes superoxide dismutase and glutathione peroxidase, compared to untreated diabetic animals. The results also show the beneficial influence of S. boulardii in regulating the hepatic concentration of renin angiotensin system (RAS) peptides. Therefore, our results demonstrated that S. boulardii administration to STZ-induced diabetic mice reduces oxidative stress and normalizes the concentration of RAS peptides, supporting the hypothesis that this yeast may have a role as a potential adjunctive therapy to attenuate diabetes-induced liver injury.

In vivo toxicity and antimicrobial activity of AuPt bimetallic nanoparticles

Despite the potential antimicrobial activity of metallic nanoparticles, the increasing concerns about nanosafety have been holding back the use of these materials in therapeutics and biomedical devices. In the last years, several studies called attention to metallic nanoparticles toxicity. In the most part of in vitro studies performed with mammalian cells, metallic NPs reduced cell viability and induced genotoxicity and inflammatory responses. Bimetallic NPs have attracted great attention because they present distinct and even more advanced characteristics when compared to nanoparticles formed by a single metal. Recently, bimetallic NPs have emerged as an alternative to improve the antimicrobial activity of metallic nanoparticles, aiming at the broadening of the action spectrum and the reduction of the toxicity. However, the biocompatibility of bimetallic nanoparticles has been demonstrated only by in vitro studies. In the present work, the toxicity of AuPt nanoparticles was addressed both in vitro and in vivo. In addition, the antimicrobial activity of AuPt bimetallic nanoparticles has been evaluated in comparison with Au and Ag nanoparticles. The nanoparticles were characterized by ultraviolet-visible spectroscopy, dynamic light scattering, transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, and X-ray diffraction. The antimicrobial activity was studied against Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. The toxicity of nanoparticles was evaluated in vitro by analyzing their toxicity against human fibroblast cells (HS68 cell line) and in vivo by embryonic toxicity test in zebrafish (Danio rerio). The results confirmed the intrinsic antimicrobial activity of the three types of nanoparticles but different toxicity. Bimetallic nanoparticles showed enhanced antimicrobial activity in comparison with Au nanoparticles but lower antimicrobial activity compared with Ag nanoparticles. However, AuPt nanoparticles showed great advantage over Ag nanoparticles due to the absence of cytotoxicity and lower toxicity in vivo.

In vivo toxicity and antimicrobial activity of AuPt bimetallic nanoparticles

Despite the potential antimicrobial activity of metallic nanoparticles, the increasing concerns about nanosafety have been holding back the use of these materials in therapeutics and biomedical devices. In the last years, several studies called attention to metallic nanoparticles toxicity. In the most part of in vitro studies performed with mammalian cells, metallic NPs reduced cell viability and induced genotoxicity and inflammatory responses. Bimetallic NPs have attracted great attention because they present distinct and even more advanced characteristics when compared to nanoparticles formed by a single metal. Recently, bimetallic NPs have emerged as an alternative to improve the antimicrobial activity of metallic nanoparticles, aiming at the broadening of the action spectrum and the reduction of the toxicity. However, the biocompatibility of bimetallic nanoparticles has been demonstrated only by in vitro studies. In the present work, the toxicity of AuPt nanoparticles was addressed both in vitro and in vivo. In addition, the antimicrobial activity of AuPt bimetallic nanoparticles has been evaluated in comparison with Au and Ag nanoparticles. The nanoparticles were characterized by ultraviolet-visible spectroscopy, dynamic light scattering, transmission electron microscopy, inductively coupled plasma optical emission spectroscopy, and X-ray diffraction. The antimicrobial activity was studied against Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus. The toxicity of nanoparticles was evaluated in vitro by analyzing their toxicity against human fibroblast cells (HS68 cell line) and in vivo by embryonic toxicity test in zebrafish (Danio rerio). The results confirmed the intrinsic antimicrobial activity of the three types of nanoparticles but different toxicity. Bimetallic nanoparticles showed enhanced antimicrobial activity in comparison with Au nanoparticles but lower antimicrobial activity compared with Ag nanoparticles. However, AuPt nanoparticles showed great advantage over Ag nanoparticles due to the absence of cytotoxicity and lower toxicity in vivo.

Tuberculosis in HIV-infected infants, children, and adolescents in Latin America

Objective: To evaluate the occurrence, clinical presentations and diagnostic methods for tuberculosis in a cohort of HIV-infected infants, children and adolescents from Latin America. Methods: A retrospective analysis of children with tuberculosis and HIV was performed within a prospective observational cohort study conducted at multiple clinical sites in Latin America. Results: Of 1114 HIV-infected infants, children, and adolescents followed from 2002 to 2011, 69 that could be classified as having confirmed or presumed tuberculosis were included in this case series; 52.2% (95% CI: 39.8-64.4%) had laboratory-confirmed tuberculosis, 15.9% (95% CI: 8.2-26.7%) had clinically confirmed disease and 31.9% (95% CI: 21.2-44.2%) had presumed tuberculosis. Sixty-six were perinatally HIV-infected. Thirty-two (61.5%) children had a history of contact with an adult tuberculosis case; however information on exposure to active tuberculosis was missing for 17 participants. At the time of tuberculosis diagnosis, 39 were receiving antiretroviral therapy. Sixteen of these cases may have represented immune reconstitution inflammatory syndrome. Conclusions: Our study emphasizes the need for adequate contact tracing of adult tuberculosis cases and screening for HIV or tuberculosis in Latin American children diagnosed with either condition. Preventive strategies in tuberculosis-exposed, HIV-infected children should be optimized. .

Tuberculosis in HIV-infected infants, children, and adolescents in Latin America.

OBJECTIVE: To evaluate the occurrence, clinical presentations and diagnostic methods for tuberculosis in a cohort of HIV-infected infants, children and adolescents from Latin America. METHODS: A retrospective analysis of children with tuberculosis and HIV was performed within a prospective observational cohort study conducted at multiple clinical sites in Latin America. RESULTS: Of 1114 HIV-infected infants, children, and adolescents followed from 2002 to 2011, 69 that could be classified as having confirmed or presumed tuberculosis were included in this case series; 52.2% (95% CI: 39.8-64.4%) had laboratory-confirmed tuberculosis, 15.9% (95% CI: 8.2-26.7%) had clinically confirmed disease and 31.9% (95% CI: 21.2-44.2%) had presumed tuberculosis. Sixty-six were perinatally HIV-infected. Thirty-two (61.5%) children had a history of contact with an adult tuberculosis case; however information on exposure to active tuberculosis was missing for 17 participants. At the time of tuberculosis diagnosis, 39 were receiving antiretroviral therapy. Sixteen of these cases may have represented immune reconstitution inflammatory syndrome. CONCLUSIONS: Our study emphasizes the need for adequate contact tracing of adult tuberculosis cases and screening for HIV or tuberculosis in Latin American children diagnosed with either condition. Preventive strategies in tuberculosis-exposed, HIV-infected children should be optimized.