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INTRODUCTION: Exposure to xylazine has been associated with wounds distinct from typical injection-related skin and soft tissue infections. We sought to understand drug use and wound care practices, and treatment experiences of people who use drugs (PWUD) in a high-prevalence area of xylazine adulteration. METHODS: In August 2023, we surveyed adult PWUD reporting at least one past-year drug use-related wound across three Massachusetts syringe service programs. Using a representative illustration, participants indicated if they had experienced a xylazine wound in the past 90 days. We compared demographic, drug use factors, wound care, and medical treatment experiences among those with and without xylazine wounds. We also conducted additional content analysis of open-ended responses. RESULTS: Of the 171 respondents, 87 % (n=148) had a xylazine wound in the past 90 days. There were no statistically significant demographic differences between those with and without xylazine wounds. Among those primarily injecting (n=155), subcutaneous injection was nearly ten times more likely among people with xylazine wounds. For those with xylazine wounds (n=148), many engaged in heterogeneous wound self-treatment practices, and when seeking medical care, 74 % experienced healthcare stigma and 58 % had inadequate pain and withdrawal management. CONCLUSION: People with self-identified xylazine wounds were more likely to engage in subcutaneous injection and faced several barriers seeking medical wound treatment. Programs serving people exposed to xylazine should work to support safer injection practices, including alternatives to injecting and improving access to high-quality, effective wound care. Further study is warranted to understand the causes, promoters, and prevention of xylazine-related wounds.
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The goal of systems biology is to gain a network level understanding of how gene interactions influence biological states, and ultimately inform upon human disease. Given the scale and scope of systems biology studies, resource constraints often limit researchers when validating genome-wide phenomena and potentially lead to an incomplete understanding of the underlying mechanisms. Further, prioritization strategies are often biased towards known entities (e.g. previously studied genes/proteins with commercially available reagents), and other technical issues that limit experimental breadth. Here, heterogeneous biological information is modeled as an association graph to which a high-performance minimum dominating set solver is applied to maximize coverage across the graph, and thus increase the breadth of experimentation. First, we tested our model on retrieval of existing gene functional annotations and demonstrated that minimum dominating set returns more diverse terms when compared to other computational methods. Next, we utilized our heterogenous network and minimum dominating set solver to assist in the process of identifying understudied genes to be interrogated by the International Mouse Phenotyping Consortium. Using an unbiased algorithmic strategy, poorly studied genes are prioritized from the remaining thousands of genes yet to be characterized. This method is tunable and extensible with the potential to incorporate additional user-defined prioritizing information. The minimum dominating set approach can be applied to any biological network in order to identify a tractable subset of features to test experimentally or to assist in prioritizing candidate genes associated with human disease.
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The biomedical research community addresses reproducibility challenges in animal studies through standardized nomenclature, improved experimental design, transparent reporting, data sharing, and centralized repositories. The ARRIVE guidelines outline documentation standards for laboratory animals in experiments, but genetic information is often incomplete. To remedy this, we propose the Laboratory Animal Genetic Reporting (LAG-R) framework. LAG-R aims to document animals' genetic makeup in scientific publications, providing essential details for replication and appropriate model use. While verifying complete genetic compositions may be impractical, better reporting and validation efforts enhance reliability of research. LAG-R standardization will bolster reproducibility, peer review, and overall scientific rigor.
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Animais de Laboratório , Guias como Assunto , Animais , Animais de Laboratório/genética , Reprodutibilidade dos Testes , Projetos de Pesquisa , Experimentação Animal/normas , Pesquisa Biomédica/normasRESUMO
OBJECTIVES: As xylazine increasingly adulterates the unregulated opioid supply, people who use drugs (PWUD) are more likely to experience sequalae from xylazine. Given xylazine exposure is consistently associated with development of wounds which can heal with medically directed wound care, we sought to understand the level of preparedness and ability of front-line addiction professionals who interact with PWUD to provide wound care treatment. METHODS: We administered a 26-item online survey assessing participant and organizational characteristics, level of wound care training, ability to test for xylazine and treat xylazine-associated wounds, and funding and billing characteristics to a national sample of addiction professionals using a listserv of over 11,000 individuals. RESULTS: We had a response rate of 12.8% in which 1,280 met eligibility criteria and completed the survey, with the majority (23.7%) being nurses. While nearly all participants had cared for patients who had experienced any xylazine-associated harms, less than half (43.6%) had cared for patients with xylazine wounds and 43.4% had any training or certification in wound care, including 26.9% of physicians. Although 75.9% of participants had access to wound care supplies, just 19.5% provided wound care services onsite. CONCLUSIONS: Most addiction professionals, especially physicians, lack wound care training and do not provide onsite treatment for drug-associated wounds at the organizational level. There is a critical need to bridge this gap in knowledge and build capacity to provide evidence-based wound care services to PWUD in areas impacted by xylazine adulteration.
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Mutations in Prkra gene, which encodes PACT/RAX cause early onset primary dystonia DYT-PRKRA, a movement disorder that disrupts coordinated muscle movements. PACT/RAX activates protein kinase R (PKR, aka EIF2AK2) by a direct interaction in response to cellular stressors to mediate phosphorylation of the α subunit of the eukaryotic translation initiation factor 2 (eIF2α). Mice homozygous for a naturally arisen, recessively inherited frameshift mutation, Prkra lear-5J exhibit progressive dystonia. In the present study, we investigate the biochemical and developmental consequences of the Prkra lear-5J mutation. Our results indicate that the truncated PACT/RAX protein retains its ability to interact with PKR, however, it inhibits PKR activation. Furthermore, mice homozygous for the mutation have abnormalities in the cerebellar development as well as a severe lack of dendritic arborization of Purkinje neurons. Additionally, reduced eIF2α phosphorylation is noted in the cerebellums and Purkinje neurons of the homozygous Prkra lear-5J mice. These results indicate that PACT/RAX mediated regulation of PKR activity and eIF2α phosphorylation plays a role in cerebellar development and contributes to the dystonia phenotype resulting from this mutation.
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BACKGROUND: Recurrent ventricular tachycardia (VT) can be treated by substrate modification of the myocardial scar by catheter ablation during sinus rhythm without VT induction. Better defining this arrhythmic substrate could help improve outcome and reduce ablation burden. OBJECTIVE: The study aimed to limit ablation within postinfarction scar to conduction channels within the scar to reduce VT recurrence. METHODS: Patients undergoing catheter ablation for recurrent implantable cardioverter-defibrillator therapy for postinfarction VT were recruited at 5 centers. Left ventricular maps were collected on CARTO using a Pentaray catheter. Ripple mapping was used to categorize infarct scar potentials (SPs) by timing. Earliest SPs were ablated sequentially until there was loss of the terminal SPs without their direct ablation. The primary outcome measure was sustained VT episodes as documented by device interrogations at 1 year, which was compared with VT episodes in the year before ablation. RESULTS: The study recruited 50 patients (mean left ventricular ejection fraction, 33% ± 9%), and 37 patients (74%) met the channel ablation end point with successful loss of latest SPs without direct ablation. There were 16 recurrences during 1-year follow-up. There was a 90% reduction in VT burden from 30.2 ± 53.9 to 3.1 ± 7.5 (P < .01) per patient, with a concomitant 88% reduction in appropriate shocks from 2.1 ± 2.7 to 0.2 ± 0.9 (P < .01). There were 8 deaths during follow-up. Those who met the channel ablation end point had no significant difference in mortality, recurrence, or VT burden but had a significantly lower ablation burden of 25.7 ± 4.2 minutes vs 39.9 ± 6.1 minutes (P = .001). CONCLUSION: Scar channel ablation is feasible by ripple mapping and can be an alternative to more extensive substrate modification techniques.
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Mitochondrial diseases (MtD) represent a significant public health challenge due to their heterogenous clinical presentation, often severe and progressive symptoms, and the lack of effective therapies. Environmental exposures, such bacterial and viral infection, can further compromise mitochondrial function and exacerbate the progression of MtD. Infections in MtD patients more frequently progress to sepsis, pneumonia, and other detrimental inflammatory endpoints. However, the underlying immune alterations that enhance immunopathology in MtD remain unclear, constituting a key gap in knowledge that complicates treatment and increases mortality in this population. Here we employ in vitro and in vivo approaches to clarify the molecular and cellular basis for innate immune hyperactivity in models of polymerase gamma (Polg)-related MtD. We reveal that type I interferon (IFN-I)-mediated upregulation of caspase-11 and guanylate-binding proteins (GBPs) increase macrophage sensing of the opportunistic microbe Pseudomonas aeruginosa (PA) in Polg mutant mice. Furthermore, we show that excessive macrophage cytokine secretion and pyroptotic cell death contribute to lung inflammation and morbidity after infection with PA. Our work sheds new light on innate immune dysregulation in MtD and reveals potential targets for limiting infection- and inflammation-related complications in Polg-related MtD.
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PURPOSE: Existing resources that characterize the essentiality status of genes are based on either proliferation assessment in human cell lines, viability evaluation in mouse knockouts, or constraint metrics derived from human population sequencing studies. Several repositories document phenotypic annotations for rare disorders; however, there is a lack of comprehensive reporting on lethal phenotypes. METHODS: We queried Online Mendelian Inheritance in Man for terms related to lethality and classified all Mendelian genes according to the earliest age of death recorded for the associated disorders, from prenatal death to no reports of premature death. We characterized the genes across these lethality categories, examined the evidence on viability from mouse models and explored how this information could be used for novel gene discovery. RESULTS: We developed the Lethal Phenotypes Portal to showcase this curated catalog of human essential genes. Differences in the mode of inheritance, physiological systems affected, and disease class were found for genes in different lethality categories, as well as discrepancies between the lethal phenotypes observed in mouse and human. CONCLUSION: We anticipate that this resource will aid clinicians in the diagnosis of early lethal conditions and assist researchers in investigating the properties that make these genes essential for human development.
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Genes Letais , Doenças Genéticas Inatas , Fenótipo , Humanos , Animais , Camundongos , Doenças Genéticas Inatas/genética , Bases de Dados Genéticas , Modelos Animais de Doenças , Genes Essenciais/genéticaRESUMO
The house mouse (Mus musculus) is an exceptional model system, combining genetic tractability with close evolutionary affinity to humans1,2. Mouse gestation lasts only 3 weeks, during which the genome orchestrates the astonishing transformation of a single-cell zygote into a free-living pup composed of more than 500 million cells. Here, to establish a global framework for exploring mammalian development, we applied optimized single-cell combinatorial indexing3 to profile the transcriptional states of 12.4 million nuclei from 83 embryos, precisely staged at 2- to 6-hour intervals spanning late gastrulation (embryonic day 8) to birth (postnatal day 0). From these data, we annotate hundreds of cell types and explore the ontogenesis of the posterior embryo during somitogenesis and of kidney, mesenchyme, retina and early neurons. We leverage the temporal resolution and sampling depth of these whole-embryo snapshots, together with published data4-8 from earlier timepoints, to construct a rooted tree of cell-type relationships that spans the entirety of prenatal development, from zygote to birth. Throughout this tree, we systematically nominate genes encoding transcription factors and other proteins as candidate drivers of the in vivo differentiation of hundreds of cell types. Remarkably, the most marked temporal shifts in cell states are observed within one hour of birth and presumably underlie the massive physiological adaptations that must accompany the successful transition of a mammalian fetus to life outside the womb.
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Animais Recém-Nascidos , Embrião de Mamíferos , Desenvolvimento Embrionário , Gástrula , Análise de Célula Única , Imagem com Lapso de Tempo , Animais , Feminino , Camundongos , Gravidez , Animais Recém-Nascidos/embriologia , Animais Recém-Nascidos/genética , Diferenciação Celular/genética , Embrião de Mamíferos/citologia , Embrião de Mamíferos/embriologia , Desenvolvimento Embrionário/genética , Gástrula/citologia , Gástrula/embriologia , Gastrulação/genética , Rim/citologia , Rim/embriologia , Mesoderma/citologia , Mesoderma/enzimologia , Neurônios/citologia , Neurônios/metabolismo , Retina/citologia , Retina/embriologia , Somitos/citologia , Somitos/embriologia , Fatores de Tempo , Fatores de Transcrição/genética , Transcrição Gênica , Especificidade de Órgãos/genéticaRESUMO
Novel adulterants and synthetic substances are rapidly infiltrating the US drug supply causing new clinical harms. There is an urgent need for responsive education and training to address these evolving harms and mitigate new risks. Since 2020, xylazine, a veterinary tranquilizer, has become increasingly common in the illicit opioid supply, especially alongside fentanyl. Training and technical assistance (TTA) programs employing an adaptive model can quickly disseminate emerging information and provide the tools to respond effectively. We describe our TTA program's experience developing and delivering virtual instructor-led xylazine training to a diverse group of addiction care professionals. The training objectives included the following: (1) introducing epidemiologic trends, pharmacology, and existing literature related to xylazine; (2) reviewing xylazine-associated harms and management; and (3) discussing harm reduction strategies related to xylazine use. We conducted 14 training sessions between October 2022 and July 2023, which were attended by over 2000 individuals across 49 states. We review our experience developing innovative training content and managing flexible training logistics and highlight our lessons learned, including targeting multidisciplinary professionals, leveraging online synchronous delivery methods, and a need for sustainable funding for TTA programs.
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Modelos Educacionais , Xilazina , Humanos , Analgésicos Opioides , Escolaridade , Preparações FarmacêuticasRESUMO
BACKGROUND: Public health-public safety partnerships for post-overdose outreach have emerged in many communities to prevent future overdose events. These efforts often identify overdose survivors through emergency call data and seek to link them with relevant services. The aim of this study was to describe how post-overdose outreach programs in Massachusetts manage the confidentiality of identifiable information and privacy of survivors. METHODS: In 2019, 138 Massachusetts programs completed surveys eliciting responses to questions about program operations. Descriptive statistics were calculated from the closed-ended survey responses. Thirty-eight interviews were conducted among outreach staff members during 2019-2020. Interview transcripts and open-ended survey responses were thematically analyzed using deductive and inductive approaches. RESULTS: Of programs that completed the survey, 90 % (n = 124/138) reported acting to protect the privacy of survivors following overdose events, and 84 % (n = 114/135) reported implementing a protocol to maintain the confidentiality of personal information. Interviews with outreach team members indicated substantial variation in practice. Outreach programs regularly employed discretion in determining actions in the field, sometimes undermining survivor privacy and confidentiality (e.g., by disclosing the overdose event to family members). Programs aiming to prioritize privacy and confidentiality attempted to make initial contact with survivors by phone, limited or concealed materials left behind when no one was home, and/or limited the number of contact attempts. CONCLUSIONS: Despite the establishment of privacy and confidentiality protocols within most post-overdose outreach programs, application of these procedures was varied, discretionary, and at times viewed by staff as competing with engagement efforts. Individual outreach overdose teams should prioritize privacy and confidentiality during outreach to protect overdose survivors from undesired exposure. In addition to individual program changes, access to overdose survivor information could be changed across all programs to bolster privacy and confidentiality protocols. For example, transitioning the management of overdose-related information to non-law enforcement agencies would limit officers' ability to disseminate such information at their discretion.
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Overdose de Drogas , Privacidade , Humanos , Confidencialidade , Overdose de Drogas/prevenção & controle , Massachusetts , FamíliaRESUMO
BACKGROUND: Three-dimensional (3D) mapping of the ventricular conduction system is challenging. OBJECTIVE: The purpose of this study was to use ripple mapping to distinguish conduction system activation to that of adjacent myocardium in order to characterize the conduction system in the postinfarct left ventricle (LV). METHODS: High-density mapping (PentaRay, CARTO) was performed during normal rhythm in patients undergoing ventricular tachycardia ablation. Ripple maps were viewed from the end of the P wave to QRS onset in 1-ms increments. Clusters of >3 ripple bars were interrogated for the presence of Purkinje potentials, which were tagged on the 3D geometry. Repeating this process allowed conduction system delineation. RESULTS: Maps were reviewed in 24 patients (mean 3112 ± 613 points). There were 150.9 ± 24.5 Purkinje potentials per map, at the left posterior fascicle (LPF) in 22 patients (92%) and at the left anterior fascicle (LAF) in 15 patients (63%). The LAF was shorter (41.4 vs 68.8 mm; P = .0005) and activated for a shorter duration (40.6 vs 64.9 ms; P = .002) than the LPF. Fourteen of 24 patients had left bundle branch block (LBBB), with 11 of 14 (78%) having Purkinje potential-associated breakout. There were fewer breakouts from the conduction system during LBBB (1.8 vs 3.4; 1.6 ± 0.6; P = .039) and an inverse correlation between breakout sites and QRS duration (P = .0035). CONCLUSION: We applied ripple mapping to present a detailed electroanatomic characterization of the conduction system in the postinfarct LV. Patients with broader QRS had fewer LV breakout sites from the conduction system. However, there was 3D mapping evidence of LV breakout from an intact conduction system in the majority of patients with LBBB.
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Ablação por Cateter , Sistema de Condução Cardíaco , Ventrículos do Coração , Infarto do Miocárdio , Taquicardia Ventricular , Humanos , Masculino , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Pessoa de Meia-Idade , Ventrículos do Coração/fisiopatologia , Ventrículos do Coração/diagnóstico por imagem , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/etiologia , Ablação por Cateter/métodos , Infarto do Miocárdio/fisiopatologia , Infarto do Miocárdio/complicações , Eletrocardiografia , Ramos Subendocárdicos/fisiopatologia , Idoso , Imageamento Tridimensional , Mapeamento Potencial de Superfície Corporal/métodosRESUMO
Essential genes are those whose function is required for cell proliferation and/or organism survival. A gene's intolerance to loss-of-function can be allocated within a spectrum, as opposed to being considered a binary feature, since this function might be essential at different stages of development, genetic backgrounds or other contexts. Existing resources that collect and characterise the essentiality status of genes are based on either proliferation assessment in human cell lines, embryonic and postnatal viability evaluation in different model organisms, and gene metrics such as intolerance to variation scores derived from human population sequencing studies. There are also several repositories available that document phenotypic annotations for rare disorders in humans such as the Online Mendelian Inheritance in Man (OMIM) and the Human Phenotype Ontology (HPO) knowledgebases. This raises the prospect of being able to use clinical data, including lethality as the most severe phenotypic manifestation, to further our characterisation of gene essentiality. Here we queried OMIM for terms related to lethality and classified all Mendelian genes into categories, according to the earliest age of death recorded for the associated disorders, from prenatal death to no reports of premature death. To showcase this curated catalogue of human essential genes, we developed the Lethal Phenotypes Portal (https://lethalphenotypes.research.its.qmul.ac.uk), where we also explore the relationships between these lethality categories, constraint metrics and viability in cell lines and mouse. Further analysis of the genes in these categories reveals differences in the mode of inheritance of the associated disorders, physiological systems affected and disease class. We highlight how the phenotypic similarity between genes in the same lethality category combined with gene family/group information can be used for novel disease gene discovery. Finally, we explore the overlaps and discrepancies between the lethal phenotypes observed in mouse and human and discuss potential explanations that include differences in transcriptional regulation, functional compensation and molecular disease mechanisms. We anticipate that this resource will aid clinicians in the diagnosis of early lethal conditions and assist researchers in investigating the properties that make these genes essential for human development.
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Substance use disorders are heritable disorders characterized by compulsive drug use, the biological mechanisms for which remain largely unknown. Genetic correlations reveal that predisposing drug-naïve phenotypes, including anxiety, depression, novelty preference and sensation seeking, are predictive of drug-use phenotypes, thereby implicating shared genetic mechanisms. High-throughput behavioral screening in knockout (KO) mice allows efficient discovery of the function of genes. We used this strategy in two rounds of candidate prioritization in which we identified 33 drug-use candidate genes based upon predisposing drug-naïve phenotypes and ultimately validated the perturbation of 22 genes as causal drivers of substance intake. We selected 19/221 KO strains (8.5%) that had a difference from control on at least one drug-naïve predictive behavioral phenotype and determined that 15/19 (~80%) affected the consumption or preference for alcohol, methamphetamine or both. No mutant exhibited a difference in nicotine consumption or preference which was possibly confounded with saccharin. In the second round of prioritization, we employed a multivariate approach to identify outliers and performed validation using methamphetamine two-bottle choice and ethanol drinking-in-the-dark protocols. We identified 15/401 KO strains (3.7%, which included one gene from the first cohort) that differed most from controls for the predisposing phenotypes. 8 of 15 gene deletions (53%) affected intake or preference for alcohol, methamphetamine or both. Using multivariate and bioinformatic analyses, we observed multiple relations between predisposing behaviors and drug intake, revealing many distinct biobehavioral processes underlying these relationships. The set of mouse models identified in this study can be used to characterize these addiction-related processes further.
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AIMS: Patients with systemic right ventricles are at high risk of sudden cardiac death. Arrhythmia is a significant risk factor. Routine Holter monitoring is opportunistic with poor adherence. The aim of this study was to determine if continuous rhythm monitoring with an implantable loop recorder (ILR) could allow early detection of clinically important arrhythmias. METHODS AND RESULTS: Implantable loop recorder implantation was offered to patients with atrial switch repair for transposition of the great arteries. Recordings were made with symptoms or, automatically for pauses, significant bradycardia or tachycardia and reviewed by the multi-disciplinary team. Twenty-four out of 36 eligible patients underwent ILR implantation with no complication. Forty-two per cent had preserved ventricular function, 75% were NYHA functional class I, 88% had low sudden cardiac death risk, 33% had previous intra-atrial re-entrant tachycardia (IART), and none had known conduction disease. Eighteen out of 24 (75%) patients made 52 recordings (52% automated) over 39.5 months (1.6-72.5). Thirty-two out of 52 (62%) recordings in 15/24 (63%) of the cohort were clinically significant and included sinus node disease (two patients), atrioventricular block (two patients), IART (seven patients), and IART with sinus node disease or atrioventricular block (four patients). Implantable loop recorder recordings prompted medication change in 11 patients [beta-blockers (n = 9), anti-coagulation (n = 5), and stopping anti-coagulation (n = 1)] and device therapy recommendation in seven patients [five pacemakers (three: atrioventricular block) and two defibrillators]. Two patients declined intervention; one suffered an arrhythmic death. Intra-atrial re-entrant tachycardia and clinically relevant conduction disease were detected in patients irrespective of sudden cardiac death risk. CONCLUSION: Continuous monitoring with an ILR in patients with systemic right ventricle following atrial switch detects clinically relevant arrhythmias that impact decision-making. In this cohort, clinically relevant arrhythmias did not correlate with sudden cardiac death risk.
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Fibrilação Atrial , Bloqueio Atrioventricular , Taquicardia Supraventricular , Transposição dos Grandes Vasos , Humanos , Ventrículos do Coração/cirurgia , Fibrilação Atrial/complicações , Bloqueio Atrioventricular/complicações , Síndrome do Nó Sinusal/complicações , Transposição dos Grandes Vasos/complicações , Taquicardia , Eletrocardiografia Ambulatorial , Taquicardia Supraventricular/terapia , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/prevenção & controleRESUMO
Gene editing in the brain has been challenging because of the restricted transport imposed by the blood-brain barrier (BBB). Current approaches mainly rely on local injection to bypass the BBB. However, such administration is highly invasive and not amenable to treating certain delicate regions of the brain. We demonstrate a safe and effective gene editing technique by using focused ultrasound (FUS) to transiently open the BBB for the transport of intravenously delivered CRISPR/Cas9 machinery to the brain.
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Encéfalo , Edição de Genes , Encéfalo/diagnóstico por imagem , Barreira Hematoencefálica , Transporte Biológico , MicrobolhasRESUMO
Substance use disorders (SUDs) are heritable disorders characterized by compulsive drug use, but the biological mechanisms driving addiction remain largely unknown. Genetic correlations reveal that predisposing drug-naïve phenotypes, including anxiety, depression, novelty preference, and sensation seeking, are predictive of drug-use phenotypes, implicating shared genetic mechanisms. Because of this relationship, high-throughput behavioral screening of predictive phenotypes in knockout (KO) mice allows efficient discovery of genes likely to be involved in drug use. We used this strategy in two rounds of screening in which we identified 33 drug-use candidate genes and ultimately validated the perturbation of 22 of these genes as causal drivers of substance intake. In our initial round of screening, we employed the two-bottle-choice paradigms to assess alcohol, methamphetamine, and nicotine intake. We identified 19 KO strains that were extreme responders on at least one predictive phenotype. Thirteen of the 19 gene deletions (68%) significantly affected alcohol use three methamphetamine use, and two both. In the second round of screening, we employed a multivariate approach to identify outliers and performed validation using methamphetamine two-bottle choice and ethanol drinking-in-the-dark protocols. We identified 15 KO strains that were extreme responders across the predisposing drug-naïve phenotypes. Eight of the 15 gene deletions (53%) significantly affected intake or preference for three alcohol, eight methamphetamine or three both (3). We observed multiple relations between predisposing behaviors and drug intake, revealing many distinct biobehavioral processes underlying these relationships. The set of mouse models identified in this study can be used to characterize these addiction-related processes further.
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Reference ranges provide a powerful tool for diagnostic decision-making in clinical medicine and are enormously valuable for understanding normality in pre-clinical scientific research that uses in vivo models. As yet, there are no published reference ranges for electrocardiography (ECG) in the laboratory mouse. The first mouse-specific reference ranges for the assessment of electrical conduction are reported herein generated from an ECG dataset of unprecedented scale. International Mouse Phenotyping Consortium data from over 26,000 conscious or anesthetized C57BL/6N wildtype control mice were stratified by sex and age to develop robust ECG reference ranges. Interesting findings include that heart rate and key elements from the ECG waveform (RR-, PR-, ST-, QT-interval, QT corrected, and QRS complex) demonstrate minimal sexual dimorphism. As expected, anesthesia induces a decrease in heart rate and was shown for both inhalation (isoflurane) and injectable (tribromoethanol) anesthesia. In the absence of pharmacological, environmental, or genetic challenges, we did not observe major age-related ECG changes in C57BL/6N-inbred mice as the differences in the reference ranges of 12-week-old compared to 62-week-old mice were negligible. The generalizability of the C57BL/6N substrain reference ranges was demonstrated by comparison with ECG data from a wide range of non-IMPC studies. The close overlap in data from a wide range of mouse strains suggests that the C57BL/6N-based reference ranges can be used as a robust and comprehensive indicator of normality. We report a unique ECG reference resource of fundamental importance for any experimental study of cardiac function in mice.
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Eletrocardiografia , Técnicas Eletrofisiológicas Cardíacas , Camundongos , Animais , Camundongos Endogâmicos C57BL , Camundongos EndogâmicosRESUMO
The external ear develops from an organized convergence of ventrally migrating neural crest cells into the first and second branchial arches. Defects in external ear position are often symptomatic of complex syndromes such as Apert, Treacher-Collins, and Crouzon Syndrome. The low set ears (Lse) spontaneous mouse mutant is characterized by the dominant inheritance of a ventrally shifted external ear position and an abnormal external auditory meatus (EAM). We identified the causative mutation as a 148 Kb tandem duplication on Chromosome 7, which includes the entire coding sequences of Fgf3 and Fgf4. Duplications of FGF3 and FGF4 occur in 11q duplication syndrome in humans and are associated with craniofacial anomalies, among other features. Intercrosses of Lse-affected mice revealed perinatal lethality in homozygotes, and Lse/Lse embryos display additional phenotypes including polydactyly, abnormal eye morphology, and cleft secondary palate. The duplication results in increased Fgf3 and Fgf4 expression in the branchial arches and additional discrete domains in the developing embryo. This ectopic overexpression resulted in functional FGF signaling, demonstrated by increased Spry2 and Etv5 expression in overlapping domains of the developing arches. Finally, a genetic interaction between Fgf3/4 overexpression and Twist1, a regulator of skull suture development, resulted in perinatal lethality, cleft palate, and polydactyly in compound heterozygotes. These data indicate a role for Fgf3 and Fgf4 in external ear and palate development and provide a novel mouse model for further interrogation of the biological consequences of human FGF3/4 duplication.