Lignocellulosic-Based Nanoparticles with Photoluminescent Properties for Bioimaging.

Natural and renewable resources from plants or animals are an important source of biomaterials due to their biocompatibility and high availability. Lignin is a biopolymer present in the biomass of plants, where it is intertwined and cross-linked with other polymers and macromolecules in the cell walls, generating a lignocellulosic material with potential applications. We have prepared lignocellulosic-based nanoparticles with an average size of 156 nm that exhibit a high photoluminescence signal when excited at 500 nm with emission in the near-infrared (NIR) region at 800 nm. The advantage of these lignocellulosic-based nanoparticles is their natural luminescent properties and their origin from rose biomass waste, which eliminates the need for encapsulation or functionalization of imaging agents. Moreover, the in vitro cell growth inhibition (IC50) of lignocellulosic-based nanoparticles is about 3 mg/mL, and no in vivo toxicity was registered up to 57 mg/kg, which suggests that they are suitable for bioimaging applications. In addition, these nanoparticles can circulate in the blood and are excreted in urine. The combined high luminescence signal in NIR, small size, low in vitro toxicity, low in vivo toxicity, and blood circulation support the potential of lignin-based nanoparticles as a novel bioimaging agent.

Knowledge, attitudes and experience of physicians working in Chile toward the prescription of pre-exposure prophylaxis (PrEP): A cross-national survey.

BACKGROUND: Pre-exposure prophylaxis (PrEP) involves administering antiretroviral drugs to prevent human immunodeficiency virus (HIV) infection in at-risk subjects. Chile is considered one of the countries with the highest number of new cases per year of HIV infections. METHODS: A nationwide cross-sectional study was carried out in Chile. A questionnaire of physicians' attitudes toward the prescription of PrEP was used. RESULTS: 632 doctors responded correctly the survey. 58.5% (n = 370) were women, and median age was 34 years (IQR 25-43). 55.4% (n = 350) responded that they have never prescribed antiretrovirals for HIV-negative individuals to prevent HIV infection, and only 10.1% have prescribed PrEP. 60.8% (n = 384) mentioned having informed about the possibility of using antiretroviral post-exposure prophylaxis in case of risky sexual activity. 76.3% (n = 482) believed each institution should formulate internal protocols for administering these drugs, and 98.4% (n = 622) stated that with the currently available evidence, PrEP should be suggested to cope with the HIV pandemic. CONCLUSION: It was concluded that knowledge, attitudes and experience toward PrEP prescribing are variable and related to patient care. However, Chile has a marked tendency in favor of this therapy, which is similar to that reported in studies worldwide.

Validación de los criterios predictivos de alto riesgo para coledocolitiasis de la Sociedad Americana de Endoscopia Gastrointestinal, 2010: Experiencia de un centro del caribe colombiano / Validation of the predictive criteria of high risk for choledocholithiasis of the american society for Gastrointestinal Endoscopy, 2010: experience of a Colombian Caribbean Center

Introducción: La colangiopancreatografía retrógrada endoscópica (CPRE) se ha convertido en el estándar de oro para el diagnóstico y tratamiento de la coledocolitiasis. La Sociedad Americana de Endoscopia Gastrointestinal (ASGE) propuso en 2010 estratificar a los pacientes en 3 niveles de riesgo; sin embargo, los estudios han encontrado resultados controvertidos sobre los parámetros predictivos de estos criterios diagnósticos. El objetivo de este estudio consiste en determinar el desempeño de los criterios predictivos de alto riesgo de la ASGE 2010 en el diagnóstico de coledocolitiasis en una población del Caribe colombiano. Métodos: Estudio transversal retrospectivo, en el que se incluyeron pacientes con sospecha de coledocolitiasis, y que fueron llevados a evaluación por CPRE, cumpliendo los criterios propuestos por la ASGE de alta probabilidad. El resultado obtenido se comparó con la presencia de coledocolitiasis en la CPRE, a partir de la cual se estimaron los valores y los intervalos de confianza del 95% para la sensibilidad, la especificidad, el valor predictivo positivo y negativo, y la razón de probabilidad positiva y negativa. Resultados: En este estudio se incluyeron los datos de 118 pacientes. La edad media de los pacientes era de 46 años (RIQ= 31; 17- 89); el 78% (n= 92) eran mujeres. El 65,3% (n= 77) eran mayores de 55 años. El resultado de la CPRE fue positivo en el 81,4% (n= 96) de los pacientes. La presencia de un perfil hepático alterado (90%) resultó ser la prueba más sensible, la colangitis clínica (86%) la más específica, la presencia de litiasis ductal por US (85%) fue la prueba con mayor valor predictivo positivo, y la presencia de litiasis ductal por US (35%) fue la prueba con mayor valor predictivo negativo. Conclusión: Los parámetros predictivos de los criterios de la ASGE 2010 para el diagnóstico de coledocolitiasis muestran variabilidad con respecto al rendimiento propuesto en las guías.

Introduction: Endoscopic retrograde cholangiopancreatography (ERCP) has become the gold standard for diagnosis and treatment of choledocholithiasis. The American Society for Gastrointestinal Endoscopy (ASGE) in 2010 proposed stratifying patients into 3 risk levels; however, studies have found controversial results about the predictive parameters of these diagnostic criteria. The objective of this study is to determine the performance of the high-risk predictive criteria of the ASGE 2010 in the diagnosis of choledocholithiasis in a Colombian Caribbean population. Methods: Retrospective cross-sectional study, which included patients with suspected choledocholithiasis, and who were taken for evaluation by ERCP, meeting the criteria proposed by the ASGE of high probability. The result obtained was compared with the presence of choledocholithiasis on ERCP, from which values and 95% confidence intervals were estimated for sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ratio. Results: A total of 118 patient data were included in this study. The median age of the patients was 46 years (IQR= 31; 17- 89); 78% (n= 92) were female. 65.3% (n= 77) were older than 55 years. The ERCP result was positive in 81.4% (n= 96) of the patients. The presence of an altered liver profile (90%) was found to be the most sensitive test, clinical cholangitis (86%) the most specific, the presence of duct lithiasis by US (85%) was the test with the highest positive predictive value, and the presence of duct lithiasis by US (35%) was the test with the highest negative predictive value. Conclusions: The predictive parameters of the ASGE 2010 criteria for the diagnosis of choledocholithiasis show variability with respect to the performance proposed in the guidelines.

Graphene Oxide Theranostic Effect: Conjugation of Photothermal and Photodynamic Therapies Based on an in vivo Demonstration.

INTRODUCTION: Cancer is the second leading cause of death globally and is responsible, where about 1 in 6 deaths in the world. Therefore, there is a need to develop effective antitumor agents that are targeted only to the specific site of the tumor to improve the efficiency of cancer diagnosis and treatment and, consequently, limit the unwanted systemic side effects currently obtained by the use of chemotherapeutic agents. In this context, due to its unique physical and chemical properties of graphene oxide (GO), it has attracted interest in biomedicine for cancer therapy. METHODS: In this study, we report the in vivo application of nanocomposites based on Graphene Oxide (nc-GO) with surface modified with PEG-folic acid, Rhodamine B and Indocyanine Green. In addition to displaying red fluorescence spectra Rhodamine B as the fluorescent label), in vivo experiments were performed using nc-GO to apply Photodynamic Therapy (PDT) and Photothermal Therapy (PTT) in the treatment of Ehrlich tumors in mice using NIR light (808 nm 1.8 W/cm2). RESULTS: This study based on fluorescence images was performed in the tumor in order to obtain the highest concentration of nc-GO in the tumor as a function of time (time after intraperitoneal injection). The time obtained was used for the efficient treatment of the tumor by PDT/PTT. DISCUSSION: The current study shows an example of successful using nc-GO nanocomposites as a theranostic nanomedicine to perform simultaneously in vivo fluorescence diagnostic as well as combined PDT-PTT effects for cancer treatments.