Gold nanoparticle-based two-photon fluorescent nanoprobe for monitoring intracellular nitric oxide levels.

Nitric oxide (NO) plays an important role in the regulation of the immune, cardiovascular and nervous systems. Consequently, being able to monitor and quantify intracellular NO levels would provide a greater understanding of the implications of this molecule in the different biological processes, including, for example, in cancer. Here, we report a broadly applicable two-photon excitable fluorescent nanoprobe able to detect and potentially quantify NO levels in an extensive range of cellular environments. The nanoprobe consists of a thiolated photoinduced electron transfer-based two=photon fluorescent probe attached onto the surface of 2.4 ± 0.7 nm gold nanoparticles (DANPY-NO@AuNPs). The nanoprobe, which can be synthesised in a reproducible manner and exhibits great stability when stored at room temperature, is able to selectively detect NO in solution, with a dynamic range up to 150 µM, and at pH values of biological relevance. DANPY-NO@AuNPs were able to selectively detect endogenous NO in RAW264.7γ NO- macrophages and THP-1 human leukemic cells; and endogenous and exogenous NO in endothelial cells. The nanoprobe accumulated in the acidic organelles of the tested cell lines showing negligible toxicity. Importantly, DANPY-NO@AuNPs showed potential to quantify intracellular NO concentrations in MDA-MB-231 breast cancer cells. The biological evaluation of the nanoprobe was undertaken using confocal laser scanning (images and intracellular emission spectra) and multiphoton microscopies, and flow cytometry. Based on their excellent sensitivity and stability, and outstanding versatility, DANPY-NO@AuNPs can be applied for the spatiotemporal monitoring of in vitro and in vivo NO levels.

A highly photostable and versatile two-photon fluorescent probe for the detection of a wide range of intracellular nitric oxide concentrations in macrophages and endothelial cells.

Nitric oxide (NO) is involved in many biological processes affecting the cardiovascular, nervous and immune systems. Intracellular NO can be monitored using fluorescent probes in combination with fluorescence imaging techniques. Most of the currently available NO fluorescent molecular probes are excited via one-photon excitation using UV or Vis light, which results in poor penetration and high photodamage to living tissues. Here, we report a two-photon fluorescent molecular probe, DANPY-NO, able to detect NO in live cells. The probe consists of an o-phenylenediamine linked to a naphthalimide core; and operates via photoinduced electron transfer. DANPY-NO exhibits good sensitivity (LOD of 77.8 nM) and high selectivity towards NO, and is stable over a broad range of pHs. The probe targeted acidic organelles within macrophages and endothelial cells, and demonstrated enhanced photostability over a commercially available NO probe. DANPY-NO was used to selectively detect endogenous NO in RAW264.7ϒ NO- macrophages, THP-1 human leukemic cells, primary mouse (bone marrow-derived) macrophages and endothelial cells. The probe was also able to detect exogenous NO in endothelial cells and distinguish between increasing concentrations of NO. The NO detection was evidenced using confocal laser scanning and two-photon microscopies, and flow cytometry. Further evidence was obtained by recording the changes in the intracellular fluorescence emission spectrum of the probe. Importantly, the probe displayed negligible toxicity to the analysed biological samples. The excellent sensitivity, selectivity, stability and versatility of DANPY-NO confirm its potential for in vitro and in vivo imaging of NO.

Precious metal complexes of bis(pyridyl)allenes: synthesis and catalytic and medicinal applications.

The incorporation of donor-type substituents on the allene core opens up the possibility of coordination complexes in which the metal is bonded to the donor groups, with or without interaction with the double bond system. Despite the challenges in the synthesis of such allene-containing metal complexes, their unique 3D environments and dual functionality (allene and metal) could facilitate catalysis and interaction with chemical and biological systems. Bis(pyridyl)allenes are presented here as robust ligands for novel Pd(II), Pt(IV) and Au(III) complexes. Their synthesis, characterisation and first application as catalysts of benchmark reactions for Pd, Pt and Au are presented with interesting reactivity and selectivities. The complexes have also been probed as antimicrobial and anticancer agents with promising activities, and the first studies on their unusual interaction with several DNA structures will open new avenues for research in the area of metallodrugs with new mechanisms of action.

Situación actual del trasplante hepático pediátrico por hepatopatías crónicas en Chile: Inequidades asociadas a la priorización por sistema MELD/PELD

Background: The Chilean allocation system for liver transplantation (LT) uses the MELD/PELD score to prioritize candidates on the waiting list. Aim: To assess if the Chilean allocation system for LT is equitable for pediatric candidates compared to their adult counterparts. Material and Methods: We used the Public Health Institute's registry between October 2011 and December 2017. We analyzed candidates with chronic hepatic diseases listed for LT. The primary outcome was the cadaveric liver transplantation (CLT) rate. Secondary outcomes were death or disease progression in the waiting list and living donor liver transplant (LDLT) rate. Results: We analyzed 122 pediatric and 735 adult candidates. Forty one percent of pediatric candidates obtained a CLT compared to 48% of adults (p = NS). Among patients aged under two years of age, the access to CLT on the waiting list there was 28% of CLT, compared to 48% in adults (p = 0.001). Fifty-seven percent of candidates aged under two years were listed for cholestatic diseases, obtaining a CLT in 18% and requiring a LDLT in 49%. The median time in the waiting list for CLT was 5.9 months in pediatric candidates and 5.1 in adults, while the median time to death in the waiting list was 2.8 and 5.6 months, respectively. The mortality rate at one year in candidates under two years old was 38.1% compared to 32.5% in adults. Conclusions: Pediatric candidates with chronic liver diseases, especially under two years of age, have greater access difficulties to CLT than adults. Half of the pediatric candidates die on the waiting list before three months. The mortality among candidates under two years of age in the waiting list is excessively high.

[Description of capsule endoscopy use in a pediatric public hospital]. / Descripción del uso de cápsula endoscópica en un hospital público pediátrico.

INTRODUCTION: Capsule endoscopy (CE) is a non-invasive technique that allows visualization of small intestine mucosa. It is used for diagnosis of lesions not accessible with other tests. Our goal was to describe the experience using CE in a pediatric public hospital in Chile. PATIENTS AND METHOD: A retrospective study was carried out to review the cases in which CE was used at Dr. Luis Calvo Mac- kenna Hospital from 2010 to date. Demographic and clinical data, findings, complications, diagnosis and treatment were recorded. RESULTS: Twenty procedures were performed in 16 patients, 11 men (69%), median age 12 years (range 3 to 15 years). Indications included polyposis study (60%), sus pected Crohn disease (20%), obscure gastrointestinal bleeding (15%) and undiagnosed anemia (5%). Seventeen studies were altered (85%) and 11 led to a diagnosis or clinical behavior change (55%). There were no complications. CONCLUSIONS: CE is a useful and safe technique in children, feasible to perform in a pediatric public hospital.

Descripción del uso de cápsula endoscópica en un hospital público pediátrico / Description of capsule endoscopy use in a pediatric public hospital

INTRODUCCIÓN: La cápsula endoscópica (CE) es a una técnica no invasiva que permite la visualización de la mucosa del intestino delgado. Se utiliza para el diagnóstico de lesiones no accesibles con otros exámenes. El objetivo fue describir la experiencia de uso de CE en un hospital público pediátrico en Chile. PACIENTES Y MÉTODO: Estudio retrospectivo en que se revisaron los casos en que se utilizó CE en el Hospital Dr. Luis Calvo Mackenna desde 2010 hasta la fecha. Se registraron datos demográficos, clínicos, hallazgos, complicaciones, diagnóstico y conducta. RESULTADOS: Se realizaron 20 procedimientos en 16 pacientes, 11 varones (69%), mediana de edad 12 años (rango 3 a 15 años). Las indicaciones incluyeron estudio de poliposis (60%), sospecha de enfermedad de Crohn (20%), hemorragia digestiva de origen desconocido (15%) y anemia de causa desconocida (5%). Diecisiete estudios estaban alterados (85%) y 11 llevaron a un diagnóstico o cambio de conducta clínica (55%). Los hallazgos principales fueron pólipos y erosiones intestinales. No se produjeron complicaciones. CONCLUSIONES: La CE es una técnica útil y segura en niños, factible de realizar en un hospital público pediátrico.

INTRODUCTION: Capsule endoscopy (CE) is a non-invasive technique that allows visualization of small intestine mucosa. It is used for diagnosis of lesions not accessible with other tests. Our goal was to describe the experience using CE in a pediatric public hospital in Chile. PATIENTS AND METHOD: A retrospective study was carried out to review the cases in which CE was used at Dr. Luis Calvo Mac kenna Hospital from 2010 to date. Demographic and clinical data, findings, complications, diagnosis and treatment were recorded. RESULTS: Twenty procedures were performed in 16 patients, 11 men (69%), median age 12 years (range 3 to 15 years). Indications included polyposis study (60%), suspected Crohn disease (20%), obscure gastrointestinal bleeding (15%) and undiagnosed anemia (5%). Seventeen studies were altered (85%) and 11 led to a diagnosis or clinical behavior change (55%). There were no complications. CONCLUSIONS: CE is a useful and safe technique in children, feasible to perform in a pediatric public hospital.

Striatal infusion of glial conditioned medium diminishes huntingtin pathology in r6/1 mice.

Huntington's disease is a neurodegenerative disorder caused by an expansion of CAG repeats in the huntingtin gene which produces widespread neuronal and glial pathology. We here investigated the possible therapeutic role of glia or glial products in Huntington's disease using striatal glial conditioned medium (GCM) from fetus mice (E16) continuously infused for 15 and 30 days with osmotic minipumps into the left striatum of R6/1 mice. Animals infused with GCM had significantly less huntingtin inclusions in the ipsilateral cerebral cortex and in the ipsilateral and contralateral striata than mice infused with cerebrospinal fluid. The numbers of DARPP-32 and TH positive neurons were also greater in the ipsilateral but not contralateral striata and substantia nigra, respectively, suggesting a neuroprotective effect of GCM on efferent striatal and nigro-striatal dopamine neurons. GCM increases activity of the autophagic pathway, as shown by the reduction of autophagic substrate, p-62, and the augmentation of LC3 II, Beclin-1 and LAMP-2 protein levels, direct markers of autophagy, in GCM infused mice. GCM also increases BDNF levels. These results suggest that CGM should be further explored as a putative neuroprotective agent in Huntington's disease.