Patient-specific vascularized tumor model: Blocking monocyte recruitment with multispecific antibodies targeting CCR2 and CSF-1R.

Tumor-associated inflammation drives cancer progression and therapy resistance, often linked to the infiltration of monocyte-derived tumor-associated macrophages (TAMs), which are associated with poor prognosis in various cancers. To advance immunotherapies, testing on immunocompetent pre-clinical models of human tissue is crucial. We have developed an in vitro model of microvascular networks with tumor spheroids or patient tissues to assess monocyte trafficking into tumors and evaluate immunotherapies targeting the human tumor microenvironment. Our findings demonstrate that macrophages in vascularized breast and lung tumor models can enhance monocyte recruitment via CCL7 and CCL2, mediated by CSF-1R. Additionally, a multispecific antibody targeting CSF-1R, CCR2, and neutralizing TGF-ß (CSF1R/CCR2/TGF-ß Ab) repolarizes TAMs towards an anti-tumoral M1-like phenotype, reduces monocyte chemoattractant protein secretion, and blocks monocyte migration. This antibody also inhibits monocyte recruitment in patient-specific vascularized tumor models. In summary, this vascularized tumor model recapitulates the monocyte recruitment cascade, enabling functional testing of innovative therapeutic antibodies targeting TAMs in the tumor microenvironment.

Expert assessment of illegal collecting impacts on Venus flytraps and priorities for research on illegal trade.

Illegal collecting of wild Venus flytraps (Dionaea muscipula) for the horticultural trade represents a persistent threat to populations of the species across their endemic range in the coastal plain of North and South Carolina (United States). Although wild collecting of Venus flytraps is not a novel threat, there has been very little research on the impacts of collecting on the species' conservation to date or why an illegal trade persists alongside a legal one. We drew on qualitative expert stakeholder elicitation to contextualize the threat of illegal collecting to the long-term conservation of Venus flytraps in relation to other anthropogenic threats. Expert elicitation included botanical and conservation researchers, cognizant state and federal agency staff, land managers, and conservation nonprofit actors. The workshop included mapping of supply chain structures and prioritization of social and environmental harms. Expert consensus determined illegal collecting is an ongoing problem for Venus flytrap conservation, but habitat destruction, degradation, and fire suppression are the most significant threats to flytrap conservation. Supply chain analysis showed that observable social and environmental harms of the trade are focused at the supply stage and that less is known about transit and demand stages. Key research gaps identified include a lack of understanding of plant laundering practices relevant to a range of desirable plant taxa; the role of commercial nurseries in illicit horticultural supply chains; motivations for engaging in Venus flytrap collecting; and the persistent demand for illegally harvested plants when cultivated, legally obtainable plants are readily available. Our findings and methodology are relevant to a range of ornamental plants affected by illegal trade for which robust social data on illegal collecting drivers are lacking.

Evaluación experta del impacto de la colecta ilegal de venus atrapamoscas y las prioridades de investigación sobre el mercado ilegal Resumen La colecta ilegal de venus atrapamoscas (Dionaea muscipula) silvestres para el mercado de horticultura representa una amenaza constante para las poblaciones de la especie a lo largo de su distribución endémica en la planicie costera de Carolina del Norte y del Sur, Estados Unidos. Aunque esta colecta no es una amenaza novedosa, a la fecha se ha investigado muy poco sobre su impacto en la conservación de la especie o por qué el mercado ilegal persiste a la par del legal. Partimos del conocimiento cualitativo de los actores expertos para contextualizar la amenaza de la colecta ilegal para la conservación a largo plazo de la venus atrapamoscas en relación con otras amenazas antropogénicas. Este conocimiento involucró a investigadores de la conservación y la botánica, personal consciente de agencias federales y estatales y actores de la conservación sin fines de lucro. El taller incluyó el mapeo de las estructuras de las cadenas de suministro y la priorización de los daños sociales y ambientales. El consenso de los expertos determinó que la colecta ilegal es un problema continuo para la conservación de la venus atrapamoscas, pero la destrucción y degradación del hábitat, así como la contención de incendios son las amenazas más significativas. El análisis de las cadenas de suministro mostró que los daños ambientales y sociales observables en el mercado se enfocan en la fase de suministro y que se sabe poco sobre las fases de tránsito y demanda. Los vacíos de investigación más importantes incluyen la falta de entendimiento de las prácticas de lavado de plantas relevantes para un rango de taxones deseables de plantas; el papel de los viveros comerciales en las cadenas de suministro de la horticultura ilícita; los motivos para participar en la colecta de venus atrapamoscas; y la demanda continua de plantas cosechadas ilegalmente cuando ya hay disponibilidad de plantas cultivadas que se obtienen legalmente. Nuestros descubrimientos y metodología son relevantes para una gama de plantas ornamentales afectadas por el mercado ilegal para las cuales hay carencia de datos sociales sólidos sobre los factores de colecta ilegal.

Racial and ethnic differences in self-reported barriers to substance use treatment among emergency department patients.

BACKGROUND AND OBJECTIVES: As overdose rates rise among non-White Americans, understanding barriers to substance use disorder (SUD) treatment access by race and ethnicity is important. This study explores self-reported barriers to SUD treatment by race and ethnicity in emergency department (ED) populations. METHODS: We conducted a secondary, exploratory analysis of a randomized trial of patients not seeking SUD treatment who endorsed active drug use at six academic EDs. Responses to the Barriers to Treatment Inventory were compared by race, ethnicity, and drug severity, using χ2 tests (N = 858), followed by adjusted logistic regression models. RESULTS: Absence of a perceived drug problem (39% non-Hispanic Black, 38% Hispanic, 50% non-Hispanic White; p ≤ .001) was the most prevalent barrier to SUD treatment. Non-Hispanic Black participants were less likely to state that they could handle their drug use on their own (OR = 0.69, CI = 0.50-0.95), and were more likely to report disliking personal questions than non-Hispanic White participants (OR = 1.49, CI = 1.07-2.09). Non-Hispanic Black participants were less likely than Hispanic participants to agree that treatment availability (OR = 0.46, CI = 0.28-0.76) and family disapproval (OR = 0.38, CI = 0.16-0.91) were treatment barriers. DISCUSSION AND CONCLUSIONS: Screening and counseling may help address the barrier, common to all groups, that drug use was not seen as problematic. Expanding access to diverse treatment options may also address the range of barriers reported by our study population. SCIENTIFIC SIGNIFICANCE: Our study is one of the first in the U.S. to examine both individual and structural barriers to accessing treatment and to examine the association with drug use severity by race/ethnicity.

Using viral diversity to identify HIV-1 variants under HLA-dependent selection in a systematic viral genome-wide screen.

The pathogenesis of HIV-1 infection is governed by a highly dynamic, time-dependent interaction between the host and the viral genome. In this study, we developed a novel systematic approach to assess the host-virus interaction, using average pairwise viral diversity as a proxy for time since infection, and applied this method to nearly whole viral genome sequences (n = 4,464), human leukocyte antigen (HLA) genotyping data (n = 1,044), and viral RNA load (VL) measurements during the untreated chronic phase (n = 829) of Swiss HIV Cohort Study participants. Our systematic genome-wide screen revealed for 98 HLA/viral-variant pairs a signature of immune-driven selection in the form of an HLA-dependent effect of infection time on the presence of HIV amino acid variants. Of these pairs, 12 were found to have an effect on VL. Furthermore, 28/58 pairs were validated by time-to-event analyses and 48/92 by computational HLA-epitope predictions. Our diversity-based approach allows a powerful and systematic investigation of the interaction between the virus and cellular immunity, revealing a notable subset of such interaction effects. From an evolutionary perspective, these observations underscore the complexity of HLA-mediated selection pressures on the virus that shape viral evolution and pathogenesis.

Feasibility of Wearable Sensors to Assess Cognitive Load During Clinical Performance: Lessons Learned and Blueprint for Success.

INTRODUCTION: Cognitive load (CogL) is increasingly recognized as an important resource underlying operative performance. Current innovations in surgery aim to develop objective performance metrics via physiological monitoring from wearable digital sensors. Surgeons have access to consumer technology that could measure CogL but need guidance regarding device selection and implementation. To realize the benefits of surgical performance improvement these methods must be feasible, incorporating human factors usability and design principles. This paper aims to evaluate the feasibility of using wearable sensors to assess CogL, identify the benefits and challenges of implementing devices, and develop guidance for surgeons planning to implement wearable devices in their research or practice. METHODS: We examined the feasibility of wearable sensors from a series of empirical studies that measured aspects of clinical performance relating to CogL. Across four studies, 84 participants and five sensors were involved in the following clinical settings: (i) real intraoperative surgery; (ii) simulated laparoscopic surgery; and (iii) medical team performance outside the hospital. RESULTS: Wearable devices worn on the wrist and chest were found to be comfortable. After a learning curve, electrodermal activity data were easily and reliably collected. Devices using photoplethysmography to determine heart rate variability were significantly limited by movement artifact. There was variable success with electroencephalography devices regarding connectivity, comfort, and usability. CONCLUSIONS: It is feasible to use wearable sensors across various clinical settings, including surgery. There are some limitations, and their implementation is context and device dependent. To scale sensor use in clinical research, surgeons must embrace human factors principles to optimize wearability, usability, reliability, and data security.

HIV-1 subtype-specific drug resistance on dolutegravir-based antiretroviral therapy: protocol for a multicentre study (DTG RESIST).

INTRODUCTION: HIV drug resistance poses a challenge to the United Nation's goal of ending the HIV/AIDS epidemic. The integrase strand transfer inhibitor (InSTI) dolutegravir, which has a higher resistance barrier, was endorsed by the WHO in 2019 for first-line, second-line and third-line antiretroviral therapy (ART). This multiplicity of roles of dolutegravir in ART may facilitate the emergence of dolutegravir resistance. METHODS AND ANALYSIS: Nested within the International epidemiology Databases to Evaluate AIDS (IeDEA), DTG RESIST is a multicentre study of adults and adolescents living with HIV in sub-Saharan Africa, Asia, and South and Central America who experienced virological failure on dolutegravir-based ART. At the time of virological failure, whole blood will be collected and processed to prepare plasma or dried blood spots. Laboratories in Durban, Mexico City and Bangkok will perform genotyping. Analyses will focus on (1) individuals who experienced virological failure on dolutegravir and (2) those who started or switched to such a regimen and were at risk of virological failure. For population (1), the outcome will be any InSTI drug resistance mutations, and for population (2) virological failure is defined as a viral load >1000 copies/mL. Phenotypic testing will focus on non-B subtype viruses with major InSTI resistance mutations. Bayesian evolutionary models will explore and predict treatment failure genotypes. The study will have intermediate statistical power to detect differences in resistance mutation prevalence between major HIV-1 subtypes; ample power to identify risk factors for virological failure and limited power for analysing factors associated with individual InSTI drug resistance mutations. ETHICS AND DISSEMINATION: The research protocol was approved by the Biomedical Research Ethics Committee at the University of KwaZulu-Natal, South Africa and the Ethics Committee of the Canton of Bern, Switzerland. All sites participate in International epidemiology Databases to Evaluate AIDS and have obtained ethics approval from their local ethics committee to collect additional data. TRIAL REGISTRATION NUMBER: NCT06285110.

Exploring Intraoperative Cognitive Biases in Cardiac Surgery Teams.

This study focuses on understanding the influence of cognitive biases in the intra-operative decision-making process within cardiac surgery teams, recognizing the complexity and high-stakes nature of such environments. We aimed to investigate the perceived prevalence and impact of cognitive biases among cardiac surgery teams, and how these biases may affect intraoperative decisions and patient safety and outcomes. A mixed-methods approach was utilized, combining quantitative ratings across 32 different cognitive biases (0 to 100 visual analogue scale), regarding their "likelihood of occurring" and "potential for patient harm" during the intraoperative phase of cardiac surgery. Based on these ratings, we collected qualitative insights on the most-rated cognitive biases from semi-structured interviews with surgeons, anaesthesiologists, and perfusionists who work in a cardiac operating room. A total of 16 participants, including cardiac surgery researchers and clinicians, took part in the study. We found a significant presence of cognitive biases, particularly confirmation bias and overconfidence, which influenced decision-making processes and had the potential for patient harm. Of 32 cognitive biases, 6 were rated above the 75th percentile for both criteria (potential for patient harm, likelihood of occurring). Our preliminary findings provide a first step toward a deeper understanding of the complex cognitive mechanisms that underlie clinical reasoning and decision-making in the operating room. Future studies should further explore this topic, especially the relationship between the occurrence of intraoperative cognitive biases and postoperative surgical outcomes. Additionally, the impact of metacognition strategies (e.g. debiasing training) on reducing the impact of cognitive bias and improving intraoperative performance should also be investigated.

Cerebellar Atrophy and Language Processing in Chronic Left-Hemisphere Stroke.

Chronic stroke results in significant downstream changes at connected cortical sites. However, less is known about the impact of cortical stroke on cerebellar structure. Here, we examined the relationship between chronic stroke, cerebellar volume, cerebellar symmetry, language impairment, and treatment trajectories in a large cohort (N = 249) of chronic left hemisphere (LH) stroke patients with aphasia, using a healthy aging cohort (N = 244) as control data. Cerebellar gray matter volume was significantly reduced in chronic LH stroke relative to healthy control brains. Within the chronic LH stroke group, we observed a robust relationship between cerebellar volume, lesion size, and days post-stroke. Notably, the extent of cerebellar atrophy in chronic LH patients, particularly in the contralesional (right) cerebellar gray matter, explained significant variability in post-stroke aphasia severity, as measured by the Western Aphasia Battery-Revised, above and beyond traditional considerations such as cortical lesion size, days post-stroke, and demographic measures (age, race, sex). In a subset of participants that took part in language treatment studies, greater cerebellar gray matter volume was associated with greater treatment gains. These data support the importance of considering both cerebellar volume and symmetry in models of post-stroke aphasia severity and recovery.

Utilizing convolutional neural networks for discriminating cancer and stromal cells in three-dimensional cell culture images with nuclei counterstain.

Significance: Accurate cell segmentation and classification in three-dimensional (3D) images are vital for studying live cell behavior and drug responses in 3D tissue culture. Evaluating diverse cell populations in 3D cell culture over time necessitates non-toxic staining methods, as specific fluorescent tags may not be suitable, and immunofluorescence staining can be cytotoxic for prolonged live cell cultures. Aim: We aim to perform machine learning-based cell classification within a live heterogeneous cell culture population grown in a 3D tissue culture relying only on reflectance, transmittance, and nuclei counterstained images obtained by confocal microscopy. Approach: In this study, we employed a supervised convolutional neural network (CNN) to classify tumor cells and fibroblasts within 3D-grown spheroids. These cells are first segmented using the marker-controlled watershed image processing method. Training data included nuclei counterstaining, reflectance, and transmitted light images, with stained fibroblast and tumor cells as ground-truth labels. Results: Our results demonstrate the successful marker-controlled watershed segmentation of 84% of spheroid cells into single cells. We achieved a median accuracy of 67% (95% confidence interval of the median is 65-71%) in identifying cell types. We also recapitulate the original 3D images using the CNN-classified cells to visualize the original 3D-stained image's cell distribution. Conclusion: This study introduces a non-invasive toxicity-free approach to 3D cell culture evaluation, combining machine learning with confocal microscopy, opening avenues for advanced cell studies.

Decoupling HIV-1 antiretroviral drug inhibition from plasma antibody activity to evaluate broadly neutralizing antibody therapeutics and vaccines.

The development of broadly neutralizing antibody (bnAb)-based therapeutic HIV-1 vaccines and cure concepts depends on monitoring bnAb plasma activity in people with HIV (PWH) on suppressive antiretroviral therapy (ART). To enable this, analytical strategies must be defined to reliably distinguish antibody-based neutralization from drug inhibition. Here, we explore strategies that either utilize drug-resistant viruses or remove drugs from plasma. We develop ART-DEX (ART dissociation and size exclusion), an approach which quantitatively separates drugs from plasma proteins following pH-triggered release allowing accurate definition of antibody-based neutralization. We demonstrate that ART-DEX, alone or combined with ART-resistant viruses, provides a highly effective and scalable means of assessing antibody neutralization during ART. Implementation of ART-DEX in standard neutralization protocols should be considered to enhance the analytical capabilities of studies evaluating bnAb therapeutics and therapeutic vaccines, furthering the development of advanced ART and HIV-1 cure strategies.

Loss of RREB1 reduces adipogenesis and improves insulin sensitivity in mouse and human adipocytes.

There are multiple independent genetic signals at the Ras-responsive element binding protein 1 (RREB1) locus associated with type 2 diabetes risk, fasting glucose, ectopic fat, height, and bone mineral density. We have previously shown that loss of RREB1 in pancreatic beta cells reduces insulin content and impairs islet cell development and function. However, RREB1 is a widely expressed transcription factor and the metabolic impact of RREB1 loss in vivo remains unknown. Here, we show that male and female global heterozygous knockout (Rreb1 +/-) mice have reduced body length, weight, and fat mass on high-fat diet. Rreb1+/- mice have sex- and diet-specific decreases in adipose tissue and adipocyte size; male mice on high-fat diet had larger gonadal adipocytes, while males on standard chow and females on high-fat diet had smaller, more insulin sensitive subcutaneous adipocytes. Mouse and human precursor cells lacking RREB1 have decreased adipogenic gene expression and activated transcription of genes associated with osteoblast differentiation, which was associated with Rreb1 +/- mice having increased bone mineral density in vivo. Finally, human carriers of RREB1 T2D protective alleles have smaller adipocytes, consistent with RREB1 loss-of-function reducing diabetes risk.

Yersinia pestis and pneumonic plague: Insight into how a lethal pathogen interfaces with innate immune populations in the lung to cause severe disease.

Yersinia pestis is the causative agent of bubonic, septicemic and pneumonic plague. The historical importance and potential of plague to re-emerge as a threat worldwide are indisputable. The most severe manifestion of plague is pneumonic plague, which results in disease that is 100% lethal without treatment. Y. pestis suppresses host immune responses early in the lung to establish infection. The later stages of infection see the rapid onset of hyperinflammatory responses that prove lethal. The study of Y. pestis host/pathogen interactions have largely been investigated during bubonic plague and with attenuated strains in cell culture models. There remains a somewhat limited understanding of the interactions between virulent Y. pestis and immune populations in the lung that drive severe disease. In this review we give a broad overview of the progression of pneumonic plague and highlighting how Y. pestis interfaces with host innate immune populations in the lung to cause lethal disease.

Personalized Vascularized Models of Breast Cancer Desmoplasia Reveal Biomechanical Determinants of Drug Delivery to the Tumor.

Desmoplasia in breast cancer leads to heterogeneity in physical properties of the tissue, resulting in disparities in drug delivery and treatment efficacy among patients, thus contributing to high disease mortality. Personalized in vitro breast cancer models hold great promise for high-throughput testing of therapeutic strategies to normalize the aberrant microenvironment in a patient-specific manner. Here, tumoroids assembled from breast cancer cell lines (MCF7, SKBR3, and MDA-MB-468) and patient-derived breast tumor cells (TCs) cultured in microphysiological systems including perfusable microvasculature reproduce key aspects of stromal and vascular dysfunction causing impaired drug delivery. Models containing SKBR3 and MDA-MB-468 tumoroids show higher stromal hyaluronic acid (HA) deposition, vascular permeability, interstitial fluid pressure (IFP), and degradation of vascular HA relative to models containing MCF7 tumoroids or models without tumoroids. Interleukin 8 (IL8) secretion is found responsible for vascular dysfunction and loss of vascular HA. Interventions targeting IL8 or stromal HA normalize vascular permeability, perfusion, and IFP, and ultimately enhance drug delivery and TC death in response to perfusion with trastuzumab and cetuximab. Similar responses are observed in patient-derived models. These microphysiological systems can thus be personalized by using patient-derived cells and can be applied to discover new molecular therapies for the normalization of the tumor microenvironment.

Polyploidy of MDA-MB-231 cells drives increased extravasation with enhanced cell-matrix adhesion.

Metastasis, the leading cause of cancer-related deaths, involves a complex cascade of events, including extravasation. Despite extensive research into metastasis, the mechanisms underlying extravasation remain unclear. Molecular targeted therapies have advanced cancer treatment, yet their efficacy is limited, prompting exploration into novel therapeutic targets. Here, we showed the association of polyploidy in MDA-MB-231 breast cancer cells and their extravasation, using microfluidic systems to reproduce the in vivo microvascular environment. We observed enhanced extravasation in polyploid cells alongside upregulated expression of genes involved in cell-substrate adhesion and cell mechanical dynamics. These findings offer insights into the relationship between polyploidy and extravasation, highlighting potential targets for cancer therapy.

A causal machine-learning framework for studying policy impact on air pollution: A case-study in COVID-19 lockdowns.

When studying the impact of policy interventions or natural experiments on air pollution, such as new environmental policies and opening or closing an industrial facility, careful statistical analysis is needed to separate causal changes from other confounding factors. Using COVID-19 lockdowns as a case-study, we present a comprehensive framework for estimating and validating causal changes from such perturbations. We propose using flexible machine learning-based comparative interrupted time series (CITS) models for estimating such a causal effect. We outline the assumptions required to identify causal effects, showing that many common methods rely on strong assumptions that are relaxed by machine learning models. For empirical validation, we also propose a simple diagnostic criterion, guarding against false effects in baseline years when there was no intervention. The framework is applied to study the impact of COVID-19 lockdowns on NO2 in the eastern US. The machine learning approaches guard against false effects better than common methods and suggest decreases in NO2 in Boston, New York City, Baltimore, and Washington D.C. The study showcases the importance of our validation framework in selecting a suitable method and the utility of a machine learning based CITS model for studying causal changes in air pollution time series.

Self-reported neurocognitive complaints in the Swiss HIV Cohort Study: a viral genome-wide association study.

People with HIV may report neurocognitive complaints, with or without associated neurocognitive impairment, varying between individuals and populations. While the HIV genome could play a major role, large systematic viral genome-wide screens to date are lacking. The Swiss HIV Cohort Study biannually enquires neurocognitive complaints. We quantified broad-sense heritability estimates using partial 'pol' sequences from the Swiss HIV Cohort Study resistance database and performed a viral near full-length genome-wide association study for the longitudinal area under the curve of neurocognitive complaints. We performed all analysis (i) restricted to HIV Subtype B and (ii) including all HIV subtypes. From 8547 people with HIV with neurocognitive complaints, we obtained 6966 partial 'pol' sequences and 2334 near full-length HIV sequences. Broad-sense heritability estimates for presence of memory loss complaints ranged between 1% and 17% (Subtype B restricted 1-22%) and increased with the stringency of the phylogenetic distance thresholds. The genome-wide association study revealed one amino acid (Env L641E), after adjusting for multiple testing, positively associated with memory loss complaints (P = 4.3 * 10-6). Other identified mutations, while insignificant after adjusting for multiple testing, were reported in other smaller studies (Tat T64N, Env *291S). We present the first HIV genome-wide association study analysis of neurocognitive complaints and report a first estimate for the heritability of neurocognitive complaints through HIV. Moreover, we could identify one mutation significantly associated with the presence of memory loss complaints. Our findings indicate that neurocognitive complaints are polygenetic and highlight advantages of a whole genome approach for pathogenicity determination.

Toward AI-driven neuroepigenetic imaging biomarker for alcohol use disorder: A proof-of-concept study.

Alcohol use disorder (AUD) is a disorder of clinical and public health significance requiring novel and improved therapeutic solutions. Both environmental and genetic factors play a significant role in its pathophysiology. However, the underlying epigenetic molecular mechanisms that link the gene-environment interaction in AUD remain largely unknown. In this proof-of-concept study, we showed, for the first time, the neuroepigenetic biomarker capability of non-invasive imaging of class I histone deacetylase (HDAC) epigenetic enzymes in the in vivo brain for classifying AUD patients from healthy controls using a machine learning approach in the context of precision diagnosis. Eleven AUD patients and 16 age- and sex-matched healthy controls completed a simultaneous positron emission tomography-magnetic resonance (PET/MR) scan with the HDAC-binding radiotracer [11C]Martinostat. Our results showed lower HDAC expression in the anterior cingulate region in AUD. Furthermore, by applying a genetic algorithm feature selection, we identified five particular brain regions whose combined [11C]Martinostat relative standard uptake value (SUVR) features could reliably classify AUD vs. controls. We validate their promising classification reliability using a support vector machine classifier. These findings inform the potential of in vivo HDAC imaging biomarkers coupled with machine learning tools in the objective diagnosis and molecular translation of AUD that could complement the current diagnostic and statistical manual of mental disorders (DSM)-based intervention to propel precision medicine forward.

Subthreshold activation of the melanocortin system causes generalized sensitization to anorectic agents in mice.

The melanocortin-3 receptor (MC3R) regulates GABA release from agouti-related protein (AgRP) nerve terminals and thus tonically suppresses multiple circuits involved in feeding behavior and energy homeostasis. Here, we examined the role of the MC3R and the melanocortin system in regulating the response to various anorexigenic agents. The genetic deletion or pharmacological inhibition of the MC3R, or subthreshold doses of an MC4R agonist, improved the dose responsiveness to glucagon-like peptide 1 (GLP1) agonists, as assayed by inhibition of food intake and weight loss. An enhanced anorectic response to the acute satiety factors peptide YY (PYY3-36) and cholecystokinin (CCK) and the long-term adipostatic factor leptin demonstrated that increased sensitivity to anorectic agents was a generalized result of MC3R antagonism. We observed enhanced neuronal activation in multiple hypothalamic nuclei using Fos IHC following low-dose liraglutide in MC3R-KO mice (Mc3r-/-), supporting the hypothesis that the MC3R is a negative regulator of circuits that control multiple aspects of feeding behavior. The enhanced anorectic response in Mc3r-/- mice after administration of GLP1 analogs was also independent of the incretin effects and malaise induced by GLP1 receptor (GLP1R) analogs, suggesting that MC3R antagonists or MC4R agonists may have value in enhancing the dose-response range of obesity therapeutics.

How to grow crystals for X-ray crystallography.

Growing high-quality crystals remains a necessary part of crystallography and many other techniques. This article tabulates and describes several techniques and variations that will help individuals grow high-quality crystals in preparation for crystallographic techniques and other endeavors, such as form screening. The discussion is organized to focus on low-tech approaches available in any laboratory.