Overcoming resistance to BRAFV600E inhibition in melanoma by deciphering and targeting personalized protein network alterations.

BRAFV600E melanoma patients, despite initially responding to the clinically prescribed anti-BRAFV600E therapy, often relapse, and their tumors develop drug resistance. While it is widely accepted that these tumors are originally driven by the BRAFV600E mutation, they often eventually diverge and become supported by various signaling networks. Therefore, patient-specific altered signaling signatures should be deciphered and treated individually. In this study, we design individualized melanoma combination treatments based on personalized network alterations. Using an information-theoretic approach, we compute high-resolution patient-specific altered signaling signatures. These altered signaling signatures each consist of several co-expressed subnetworks, which should all be targeted to optimally inhibit the entire altered signaling flux. Based on these data, we design smart, personalized drug combinations, often consisting of FDA-approved drugs. We validate our approach in vitro and in vivo showing that individualized drug combinations that are rationally based on patient-specific altered signaling signatures are more efficient than the clinically used anti-BRAFV600E or BRAFV600E/MEK targeted therapy. Furthermore, these drug combinations are highly selective, as a drug combination efficient for one BRAFV600E tumor is significantly less efficient for another, and vice versa. The approach presented herein can be broadly applicable to aid clinicians to rationally design patient-specific anti-melanoma drug combinations.

Restoration of energy homeostasis by SIRT6 extends healthy lifespan.

Aging leads to a gradual decline in physical activity and disrupted energy homeostasis. The NAD+-dependent SIRT6 deacylase regulates aging and metabolism through mechanisms that largely remain unknown. Here, we show that SIRT6 overexpression leads to a reduction in frailty and lifespan extension in both male and female B6 mice. A combination of physiological assays, in vivo multi-omics analyses and 13C lactate tracing identified an age-dependent decline in glucose homeostasis and hepatic glucose output in wild type mice. In contrast, aged SIRT6-transgenic mice preserve hepatic glucose output and glucose homeostasis through an improvement in the utilization of two major gluconeogenic precursors, lactate and glycerol. To mediate these changes, mechanistically, SIRT6 increases hepatic gluconeogenic gene expression, de novo NAD+ synthesis, and systemically enhances glycerol release from adipose tissue. These findings show that SIRT6 optimizes energy homeostasis in old age to delay frailty and preserve healthy aging.

Ideal Cardiovascular Health in the southern cone of Latin America.

OBJECTIVE: The American Heart Association developed the concept of 'Ideal Cardiovascular Health', which is based on the presence of ideal levels across seven health factors. The goal of this study is to assess the prevalence of Ideal Cardiovascular Health in the Southern Cone of Latin America. STUDY DESIGN: We conducted a cross-sectional analysis as part of CESCAS I cohort. METHODS: This report included 5458 participants aged between 35 and 75 years who were selected using stratified multistage probability sampling in Argentina, Chile and Uruguay. Interviews included demographic information, the International Physical Activity Questionnaire, and a food frequency questionnaire on dietary habits. Participants were classified as current, former or non-smokers. Weight, height and blood pressure were measured by trained personnel, and fasting cholesterol and glucose plasma levels were measured. RESULTS: Only 0.1% (95% confidence interval [CI]: 0.0-0.2) met the seven criteria that define the Ideal Cardiovascular Health. The least prevalent healthy behaviour was having a healthy diet: 0.5% (95% CI: 0.3-0.7), while the least prevalent health factor was having blood pressure < 120/80 mmHg: 23.6% (95% CI: 22.1-25.0). CONCLUSIONS: The prevalence of Ideal Cardiovascular Health is very low in a representative sample of population from the Southern Cone of Latin America, and the levels of healthy lifestyle behaviours are even lower than ideal biochemical parameters. These results highlight the challenge of developing strategies to improve the levels of Ideal Cardiovascular Health at primary prevention levels.

Prevention of childhood obesity and food policies in Latin America: from research to practice.

BACKGROUND: Addressing childhood obesity in Latin America requires a package of multisectoral, evidence-based policies that enable environments conducive to healthy lifestyles. OBJECTIVE: Identify and examine key elements to translating research into effective obesity policies in Latin America. METHODS: We examined obesity prevention policies through case studies developed with an expert in the specific policy. Policies were selected based on their level of implementation, visibility and potential impact to reduce childhood obesity. They include: (i) excise taxes on sugar sweetened beverages and energy-dense foods; (ii) front-of-package food label legislation; (iii) trans fatty acids removal from processed foods; and (iv) Ciclovías recreativas or 'open streets'. Case studies were coded to identify components that explained successful implementation and sustainability using the Complex Adaptive Health Systems framework. RESULTS: The analysis identified key elements for effective and sustainable policy, including evidence justifying policy; evidence-based advocacy by civil society; political will; and legislation and skillful negotiations across government, academia, the private sector and civil society. Scientific evidence and evaluation played an important role in achieving tipping points for policies' launch and sustain effective implementation. CONCLUSIONS: Well-coordinated, intersectoral partnerships are needed to successfully implement evidence-based anti-obesity policies. Prospective policy research may be useful for advancing knowledge translation.

Determinants and geographical variation in the distribution of depression in the Southern cone of Latin America: A population-based survey in four cities in Argentina, Chile and Uruguay.

BACKGROUND: Depression is one of the major contributors to the global burden of diseases; however, population-based data in South America are limited. METHODS: We conducted a population-based cross sectional study with 7524 participants, aged 35-74 years old, recruited between February 2010 and December 2011 from randomly selected samples in 4 cities (Bariloche and Marcos Paz, Argentina; Temuco, Chile; and Pando-Barros Blancos, Uruguay). Major Depressive Episode (MDE) was assessed using the Patient Health Questionnaire (PHQ) - 9. RESULTS: The overall prevalence of MDE was 14.6% (95% CI: 13.6, 15.6). However, there was a geographical variability of up to 3.7 folds between different cities being 5.6% (95% CI: 4.6, 6.7) in Marcos Paz, Argentina; 9.5% (95% CI: 8.2, 10.9) in Bariloche, Argentina; 18.1% (95% CI: 16.3, 20.0) in Temuco, Chile, and 18.2 (95% CI: 16.3, 20.2) in Pando-Barros Blancos, Uruguay. The multivariate model showed that, adjusted by location, being female, being between 35 and 44 years old, having experienced at least one stressful life event, currently smoking, and having a history of chronic medical diseases were independently associated with an increased risk of MDE, while having higher education and being married or living with a partner reduced the risk of MDE. LIMITATIONS: These results are representative of the selected cities included in the study. As such extrapolation to the general populations of Argentina, Chile, and Uruguay should be done with caution CONCLUSIONS: This study showed a high prevalence and variability of MDE in the Southern Cone of Latin America.

Single point mutation detection in living cancer cells by far-red emitting PNA-FIT probes.

Peptide nucleic acid bis-quinoline conjugates are reported as attractive far-red emitting probes that detect mutated mRNA in living cells at SNP resolution.

Lower tract respiratory infection in children younger than 5 years of age and adverse pregnancy outcomes related to household air pollution in Bariloche (Argentina) and Temuco (Chile).

The main objective of this study was to evaluate the association between household air pollution with lower tract respiratory infection (LRTI) in children younger than 5 years old and adverse pregnancy outcomes. This retrospective cohort study took place in two cities in Patagonia. Using systemic random sampling, we selected households in which at least one child <5 years had lived and/or a child had been born alive or stillborn. Trained interviewers administered the questionnaire. We included 926 households with 695 pregnancies and 1074 children. Household cooking was conducted indoors in ventilated rooms and the use of wood as the principal fuel for cooking was lower in Temuco (13% vs. 17%). In exposed to biomass fuel use, the adjusted OR for LRTI was 1.87 (95% CI 0.98-3.55; P = 0.056) in Temuco and 1.12 (95% CI 0.61-2.05; P = 0.716) in Bariloche. For perinatal morbidity, the OR was 3.11 (95% CI 0.86-11.32; P = 0.084) and 1.41 (95% CI 0.50-3.97; P = 0.518), respectively. However, none of the effects were statistically significant (P > 0.05). The use of biomass fuel to cook in traditional cookstoves in ventilated dwellings may increase the risk of perinatal morbidity and LRTI.

Enhanced cell growth by nanoengineering zirconia to stimulate electrostatic fibronectin activation.

We address the enhanced bone growth on designed nanocrystalline zirconia implants as reported by in vivo experiments. In vitro experiments demonstrate that the activation of adhesive proteins on nanoengineered zirconia stimulates cell adhesion and growth as shown by confocal microscopy. Fibrillar fibronectin (FN) forms a matrix assembly on the nanostructured surface in the cell adhesion process. We discuss the importance of FN dimer activation due to its immobilization on the designed nanocrystalline ZrO2 implant fabricated by ion beam assisted deposition. The Monte-Carlo analysis indicates that FN activation on the surface can be promoted by selective electrostatic interactions between negatively charged ZrO2 surface patches and oppositely charged FN domains.

Paediatric epidemiology of Pasteurella multocida meningitis in France and review of the literature.

We report on six cases of Pasteurella multocida (P. multocida) meningitis occurring between 2001 and 2011 by a French nationwide active surveillance network of paediatric bacterial meningitis (ACTIV/GPIP). The cases accounted for 0.15 % of the paediatric meningitis cases reported between 2001 and 2011 in France, all in infants <4 months old. A review of the literature allowed us to gather information on 42 other cases of P. multocida meningitis in infants <1 year old reported since 1963. Among all 48 cases, 44 % were newborns. An animal source of the infection, including 39 household dogs and cats, was suspected or identified in 42 of 48 cases. A traumatic contact between the child and a pet occurred in 8 % of cases, and a vertical transmission from mother to child during birth in 10.4 %. Most of the time, the infection resulted from non-traumatic contact between the child and the pet, through licking or sniffing. The absence of host risk factors suggests that an immature immune system is responsible, given the young age of the children. Although complications, especially neurological lesions, were not rare (37.5 %), the long-term outcome was usually good. Four infants died of meningitis. This rare disease could be prevented by reducing contact between infants and household pets, and by performing simple hygiene measures before handling babies.

Enhanced initial protein adsorption on engineered nanostructured cubic zirconia.

Motivated by experimentally-observed biocompatibility enhancement of nanoengineered cubic zirconia (ZrO(2)) coatings to mesenchymal stromal cells, we have carried out computational analysis of the initial immobilization of one known structural fragment of the adhesive protein (fibronectin) on the corresponding surface. We constructed an atomistic model of the ZrO(2) nano-hillock of 3-fold symmetry based on Atom Force Microscopy and Transmission Electron Microscopy images. First principle quantum mechanical calculations show a substantial variation of electrostatic potential at the hillock due to the presence of surface features such as edges and vertexes. Using an implemented Monte Carlo simulated annealing method, we found the orientation of the immobilized protein on the ZrO(2) surface and the contribution of the amino acid residues from the protein sequence to the adsorption energy. Accounting for the variation of the dielectric permittivity at the protein-implant interface, we used a model distance-dependent dielectric function to describe the inter-atom electrostatic interactions in the adsorption potential. We found that the initial immobilization of the rigid protein fragment on the nanostructured pyramidal ZrO(2) surface is achieved with a magnitude of adsorption energy larger than that of the protein on the smooth (atomically flat) surface. The strong attractive electrostatic interactions are a major contributing factor in the enhanced adsorption at the nanostructured surface. In the case of adsorption on the flat, uncharged surface this factor is negligible. We show that the best electrostatic and steric fit of the protein to the inorganic surface corresponds to a minimum of the adsorption energy determined by the non-covalent interactions.

Effect of the ordered interfacial water layer in protein complex formation: A nonlocal electrostatic approach.

Using a nonlocal electrostatic approach that incorporates the short-range structure of the contacting media, we evaluated the electrostatic contribution to the energy of the complex formation of two model proteins. In this study, we have demonstrated that the existence of an ordered interfacial water layer at the protein-solvent interface reduces the charging energy of the proteins in the aqueous solvent, and consequently increases the electrostatic contribution to the protein binding (change in free energy upon the complex formation of two proteins). This is in contrast with the finding of the continuum electrostatic model, which suggests that electrostatic interactions are not strong enough to compensate for the unfavorable desolvation effects.

A systems level strategy for analyzing the cell death network: implication in exploring the apoptosis/autophagy connection.

The mammalian cell death network comprises three distinct functional modules: apoptosis, autophagy and programmed necrosis. Currently, the field lacks systems level approaches to assess the extent to which the intermodular connectivity affects cell death performance. Here, we developed a platform that is based on single and double sets of RNAi-mediated perturbations targeting combinations of apoptotic and autophagic genes. The outcome of perturbations is measured both at the level of the overall cell death responses, using an unbiased quantitative reporter, and by assessing the molecular responses within the different functional modules. Epistatic analyses determine whether seemingly unrelated pairs of proteins are genetically linked. The initial running of this platform in etoposide-treated cells, using a few single and double perturbations, identified several levels of connectivity between apoptosis and autophagy. The knock down of caspase3 turned on a switch toward autophagic cell death, which requires Atg5 or Beclin-1. In addition, a reciprocal connection between these two autophagic genes and apoptosis was identified. By applying computational tools that are based on mining the protein-protein interaction database, a novel biochemical pathway connecting between Atg5 and caspase3 is suggested. Scaling up this platform into hundreds of perturbations potentially has a wide, general scope of applicability, and will provide the basis for future modeling of the cell death network.

Feasibility of day-case vitreoretinal surgery.

PURPOSE: The indications for vitreoretinal (VR) surgery are increasing as equipment and techniques available improve. In order to decrease demand on limited health resources, day-case surgery would be beneficial in many cases. This study combines a retrospective and prospective arm to examine the feasibility and safety of routine day-case VR surgery. METHODS: One hundred consecutive patients (50 retrospective and 50 prospective) undergoing VR surgery within the Royal Berkshire NHS trust were included. The retrospective arm aimed to identify the frequency and type of acute ophthalmic or medical intervention during postop overnight stay and the results were used to alter management in the prospective group. The prospective group consisted of patients undergoing a mixture of overnight stay and day-case surgery. All patients in the prospective group had routine subtenon marcaine anaesthesia together with prophylactic pre-operative intravenous acetazolamide. Patients deemed fit postoperatively were offered overnight ward discharge, with obligatory next-day review. RESULTS: In the retrospective arm, 56% required oral nonsteroidal analgesia on the day of surgery and one patient required narcotic analgesia. Twenty-two per cent patients required intraocular pressure (IOP) control on the day of surgery and one patient required medical intervention in the form of urinary catheterisation. Nineteen patients required intervention on next-day review. In the prospective arm, 86% preferred day case and were suitable, 6% were suitable for day-case but preferred overnight stay and 8% were deemed not fit for discharge. No patient required narcotic analgesics. No patient discharged returned as a casualty overnight. Only one patient required topical beta-blocker for the control of IOP on next-day review. CONCLUSIONS: These data suggest that many patients who are hospitalised overnight for VR surgery could be safely treated as day cases. Such a shift in the pattern of care for VR surgery could provide a significant improvement in health-care efficiency and minimise patient inconvenience.

Iatrogenic eccentric full thickness macular holes following vitrectomy with ILM peeling for idiopathic macular holes.

PURPOSE: To document a previously unreported complication after vitrectomy with peeling of the internal limiting membrane (ILM) for idiopathic macular holes. METHOD: Retrospective review of notes of 232 consecutive patients who underwent vitrectomy with peeling of the ILM for idiopathic macular holes from 1996 to 2001. Four patients were found to have eccentric iatrogenic macular holes postoperatively. Optical coherence tomography was used to evaluate these holes. RESULTS: The idiopathic macular holes were graded from stages II to IV preoperatively with visual acuities from 6/18 to 6/60. All patients had surgery within 6 months of presentation. They underwent vitrectomy with complete separation of the posterior cortical vitreous, peeling of the ILM, injection of platelets (0.1 ml), and gas tamponade with SF6 20%. Postoperatively the patients postured strictly face down for 10 days. Follow-up ranged from 8 months to 6 years. Iatrogenic eccentric macular holes were noted postoperatively. The holes were located between 3 and 6 o'clock in three patients and at 9 o'clock in the fourth patient, relative to the macula. Optical coherence tomography showed them to be full thickness and completely flat. No further intervention was necessary. No complications have arisen during follow-up. COMMENT: To our knowledge iatrogenic eccentric full thickness macular holes after macular hole surgery have never been reported. We believe that the location of the holes represents the initial site of ILM elevation. These holes are asymptomatic, have not required any treatment and have not caused any complications in up to 6 years of follow-up.