Expanded tRNA methyltransferase family member TRMT9B regulates synaptic growth and function.

Nervous system function rests on the formation of functional synapses between neurons. We have identified TRMT9B as a new regulator of synapse formation and function in Drosophila. TRMT9B has been studied for its role as a tumor suppressor and is one of two metazoan homologs of yeast tRNA methyltransferase 9 (Trm9), which methylates tRNA wobble uridines. Whereas Trm9 homolog ALKBH8 is ubiquitously expressed, TRMT9B is enriched in the nervous system. However, in the absence of animal models, TRMT9B's role in the nervous system has remained unstudied. Here, we generate null alleles of TRMT9B and find it acts postsynaptically to regulate synaptogenesis and promote neurotransmission. Through liquid chromatography-mass spectrometry, we find that ALKBH8 catalyzes canonical tRNA wobble uridine methylation, raising the question of whether TRMT9B is a methyltransferase. Structural modeling studies suggest TRMT9B retains methyltransferase function and, in vivo, disruption of key methyltransferase residues blocks TRMT9B's ability to rescue synaptic overgrowth, but not neurotransmitter release. These findings reveal distinct roles for TRMT9B in the nervous system and highlight the significance of tRNA methyltransferase family diversification in metazoans.

Macronutrient balancing affects patch departure by guerezas (Colobus guereza).

Foraging strategies are central in shaping social structure and grouping patterns in primates. We address Colobus guereza foraging strategies by investigating their patch departure decisions in relation to diet composition and nutrition. We examine whether guerezas are constrained in their intake of food in patches and thereby forage according to a fixed amount strategy that dictates patch departure. Additionally, we assess whether guereza employ a fixed time strategy or attempt to balance nutrients when foraging. We measured food patch occupancy time, intake rates, and analyzed foods for macronutrients, fiber, and condensed tannins. We determined that guerezas do not employ a fixed time foraging strategy; patch residence time varied widely between 1 and 290 min. They also did not depart patches or stop eating when they reached a specific intake of dry mass, macronutrients, or condensed tannins. However, guerezas maintained a macronutrient balance when feeding across patches, and the balance of protein to non-protein energy (fats and carbohydrates) in patches is the best indicator of time adult guerezas spent feeding in patches. Previous studies have shown that the protein-to-fiber ratio is important in predicting food selection for folivores and their biomass; however, we found that guerezas did not maximize protein and minimize fiber intake while foraging in patches, nor did they stay longer in patches with the highest ratio of protein to fiber concentrations. This study raises questions about the nutritional and social implications of patch depletion as a foraging strategy in folivorous monkeys where food limitation predicts competitive and social regimes. Am. J. Primatol. 79:e22495, 2017. © 2015 Wiley Periodicals, Inc.

Essential competencies in global health research for medical trainees: A narrative review.

INTRODUCTION: Participation in short-term educational experiences in global health (STEGHs) among medical trainees is increasingly accompanied by interest in conducting research while abroad. Because formal training in both global health and research methods is currently under-represented in most medical curricula, trainees are often unfamiliar with the knowledge, attitudes, and skills necessary to design and conduct research successfully. This narrative review identifies essential global health research competencies for medical trainees engaged in STEGHs. METHODS: The authors searched the literature using the terms global health, competency, research, research methods/process/training, scholarly project, medical student, and medical education/education. Because articles directly addressing global health research competencies for medical trainees were limited, the authors additionally drew on the broader literature addressing general research competencies and global health competencies. FINDINGS: Articles yielded by the literature search, combined with established guidelines in research ethics and global health ethics, were used to identify six core domains and twenty discrete competencies fundamental to global health research at a level appropriate for medical trainees enrolled in STEGHs. Consideration was given to diverse research modalities, varying levels of training, and the availability of mentoring and on-site support. DISCUSSION: Research may provide important benefits to medical trainees and host partners. These competencies provide a starting point; however, circumstances at any host site may necessitate additional competencies specific to that setting. These competencies are also limited by the methodology employed in their development and the need for additional perspectives from host partners. CONCLUSIONS: The competencies identified outline basic knowledge, attitudes, and skills necessary for medical trainees to conduct limited global health research while participating in STEGHS. They may also be used as a basis for curriculum development, assessment, and research capacity development.

tRNA modification enzyme-dependent redox homeostasis regulates synapse formation and memory.

Post-transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA modifying enzyme that methylates wobble uridines in specific tRNAs to modulate translation. Through methylation of tRNA-selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit a global reduction in protein synthesis, including a specific decrease in selenoprotein levels. Loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 animals also exhibit associative learning and memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA modification in redox homeostasis in the nervous system and reveal antioxidants as a potential therapy for ALKBH8-associated intellectual disability.

Exploring the use and impact of adjuvant trastuzumab for HER2-positive breast cancer patients in a large UK cancer network. Do the results of international clinical trials translate into a similar benefit for patients in South East Wales?

BACKGROUND: Trastuzumab was approved in the United Kingdom for adjuvant treatment of human epidermal growth factor receptor 2 (HER2)+ breast cancer in 2006 at significant economic cost and with limited evidence in smaller T1N0 tumours. The South East Wales Cancer Network covers a population of 1,420,000 and maintains a database of treatments used. We examined this database to ensure the outcome of Trastuzumab use is as expected, especially in patients with T1N0 cancers. METHODS: Case notes of patients with HER2+ disease eligible for adjuvant Trastuzumab over 2005-2008 were reviewed. Disease-free survival (DFS) and overall survival (OS) were calculated with the Kaplan-Meier method using SPSS (version 16.0.01 for Windows, SPSS, Chicago, IL, USA). RESULTS: A total of 239 of 338 (70.7%) eligible HER2+ patients received treatment. At 3 years, the DFS of the treated group was 90.3% vs 73.3% and the OS was 98.5% vs 87.6%. In all, 47 of 92 stage I patients received Trastuzumab. Despite a trend towards worse prognostic factors in the treated group the DFS was 100% vs 84.1% and the OS was 100% vs 93.3%. CONCLUSION: Our results are comparable to those from landmark Trastuzumab trials. As evidence continues to emerge that smaller HER2+ cancers may behave aggressively our analysis of stage I tumours adds further support to the use of Trastuzumab in these patients.

The good and the bad: alkaloid screening and brineshrimp bioassays of aqueous extracts of 31 medicinal plants of eastern Nicaragua.

CONTEXT: Presence/absence tests for alkaloids of 31 medicinal vascular plant species from 31 genera and 26 families of eastern Nicaragua provided a baseline for bioactivity tests. OBJECTIVE: To determine the bioactivity and cytoxicity of aqueous extracts of widely used medicinal species in eastern Nicaragua. MATERIALS AND METHODS: Ethnomedicinal applications were obtained from interviews of traditional healers. We used Dragendorff's reagent to test alkaloids and brine shrimp for cytotoxicity of aqueous extracts. RESULTS: Twenty-nine of the 31 species tested positive for alkaloids. The median lethal concentration that kills 50% of the larvae within 24 h of contact with the extract (LC(50) was less than 1000 µg/mL for 4 (13%) species (the usual cytotoxic category), 1001-5000 µg/mL for 23 (74%) species, and between 5001-7500 µg/mL for the remaining 4 (13%) species. DISCUSSION AND CONCLUSION: Twenty-five of the ethnomedicines contain alkaloids but are not cytotoxic. In contrast to first suppositions, we suggest that this is a good and desirable, and perhaps expected, outcome. Medicinal plants that are cytotoxic may obviously control or kill bacteria or other pathogens, but may also negatively affect the patient; some high alkaloid levels have been associated with carcinogens. Thus, perhaps the majority of effective medicinals should be expected to be noncytotoxic. We suggest that this is a new paradigm for consideration of the overall value and effectiveness of medicinals. Of course, medicinals also can be effective in numerous ways (e.g., organ stimulation or other physiological functions) other than simply as antimicrobials or antipathogens.

[Serotonin receptor 1A-modulated dephosphorylation of glycine receptor α3: a new molecular mechanism of breathing control for compensation of opioid-induced respiratory depression without loss of analgesia]. / Die von Serotoninrezeptor 1A modulierte Dephosphorylierung des Glyzinrezeptors α3: Ein neuer molekularer Mechanismus der Atmungskontrolle zur Kompensation opioidinduzierter Atemdepression ohne Verlust der Analgesie.

To control the breathing rhythm the medullary respiratory network generates periodic salvo activities for inspiration, post-inspiration and expiration. These are under permanent modulatory control by serotonergic neurons of the raphe which governs the degree of phosphorylation of the inhibitory glycine receptor α3. The specific activation of serotonin receptor type 1A (5-HTR(1A)), which is strongly expressed in the respiratory neurons, functions via inhibition of adenylate cyclase and the resulting reduction of the intracellular cAMP level and a gradual dephosphorylation of the glycine receptor type α3 (GlyRα3). This 5-HTR(1A)-GlyRα3 signal pathway is independent of the µ-opioidergic transduction pathway and via a synaptic inhibition caused by an increase in GlyRα3 stimulates a disinhibition of some target neurons not only from excitatory but also from inhibitory neurons. Our physiological investigations show that this 5-HTR(1A)-GlyRα3 modulation allows treatment of respiratory depression due to opioids without affecting the desired analgesic effects of opioids. The molecular mechanism presented here opens new pharmacological possibilities to treat opioid-induced respiratory depression and respiratory disorders due to disturbed inhibitory synaptic transmission, such as hyperekplexia.

Bone Diagenesis in Short Timescales: Insights from an Exploratory Proteomic Analysis.

The evaluation of bone diagenetic phenomena in archaeological timescales has a long history; however, little is known about the origins of the microbes driving bone diagenesis, nor about the extent of bone diagenesis in short timeframes-such as in forensic contexts. Previously, the analysis of non-collagenous proteins (NCPs) through bottom-up proteomics revealed the presence of potential biomarkers useful in estimating the post-mortem interval (PMI). However, there is still a great need for enhancing the understanding of the diagenetic processes taking place in forensic timeframes, and to clarify whether proteomic analyses can help to develop better models for estimating PMI reliably. To address these knowledge gaps, we designed an experiment based on whole rat carcasses, defleshed long rat bones, and excised but still-fleshed rat limbs, which were either buried in soil or exposed on a clean plastic surface, left to decompose for 28 weeks, and retrieved at different time intervals. This study aimed to assess differences in bone protein relative abundances for the various deposition modalities and intervals. We further evaluated the effects that extrinsic factors, autolysis, and gut and soil bacteria had on bone diagenesis via bottom-up proteomics. Results showed six proteins whose abundance was significantly different between samples subjected to either microbial decomposition (gut or soil bacteria) or to environmental factors. In particular, muscle- and calcium-binding proteins were found to be more prone to degradation by bacterial attack, whereas plasma and bone marrow proteins were more susceptible to exposure to extrinsic agents. Our results suggest that both gut and soil bacteria play key roles in bone diagenesis and protein decay in relatively short timescales, and that bone proteomics is a proficient resource with which to identify microbially-driven versus extrinsically-driven diagenesis.

Rapid Development, Training, and Implementation of a Remote Health Profession's Student Volunteer Corps During the COVID-19 Pandemic.

Public health in the United States has long been challenged by budget cuts and a declining workforce. The COVID-19 pandemic exposed the vulnerabilities left by years of neglecting this crucial frontline defense against emerging infectious diseases. In the early days of the pandemic, the University of Texas Medical Branch and the Galveston County Health District (GCHD) partnered to bolster Galveston County's public health response. We mobilized interprofessional teams of students and provided training to implement projects identified by GCHD as necessary for responding to the pandemic. We provided a safe outlet for students to contribute to their community by creating remote volunteer opportunities when students faced displacement from clinical rotations and in-person didactics converted to virtual formats. As students gradually returned to clinical rotations and didactic demands increased, it became necessary to expand volunteer efforts beyond what had initially been mostly hand-selected student teams. We have passed the initial emergency response phase of COVID-19 in Galveston County and are transitioning into more long-term opportunities as COVID-19 moves from pandemic to endemic. In this case study, we describe our successes and lessons learned.

Alkaloid presence and brine shrimp (Artemia salina) bioassay of medicinal species of eastern Nicaragua.

We used an alkaloid test and a brine shrimp bioassay to assess the bioactivity of the medicinal plants used by eastern Nicaraguan healers in traditional medicine. Ethnomedicinal uses were obtained from interviews of traditional healers. Aqueous extracts derived from 30 species of angiosperms were assayed for the presence of alkaloids and toxicity. Species tested are distributed in 30 genera and 21 families. Of the 30 species tested for alkaloids with Dragendorff's reagent, 29 contained alkaloids. Toxicological analysis was conducted using the brine shrimp lethal assay (BSLA). Biological activity using BSLA was recorded as the median lethal concentration (LC50) that kills 50% of the larvae within 24 h of contact with the aqueous plant extracts. The LC50 of the shrimp was less than 2500 microg/mL for 3 (10%) species, 2500-5000 microg/mL for 9 (30%), 5001-7500 microg/mL for 7 (23%), 7501-10000 microg/mL for 3 (10%), and greater than 10000 microg/mL for 8 (27%) of the species. The members of the orders Santales and Rubiales in general contained species with greater toxicity than any other group. Struthanthus cassythoides (Struthanthus cassythoides Millsp.(Loranthaceae)). (LC50 1574 microg/mL) and Alibertia edulis (Rich.) A. Rich. (Rubiaceae) (LC50 1741 microg/mL) were the most toxic.

Plasticity of synaptic inhibition in mouse spinal cord lamina II neurons during early postnatal development and after inactivation of the glycine receptor alpha3 subunit gene.

Synaptic inhibition mediated by GABA(A) receptors and glycine receptors (GlyRs) in the outer laminae of the spinal cord dorsal horn efficiently filters ascending nociceptive messages, controlling pathological pain symptoms. However, although many studies have utilized transgenic models to study spinal nociceptive processing, very little is known about the development of functional inhibitory synapses onto these interneurons in mice. Here we report that most interneurons in lamina II are placed under phasic control by both GABAergic and glycinergic synapses, a number of which exhibit dual GABA/glycine co-release. A developmental switch is also apparent: a subpopulation of lamina II interneurons controlled exclusively by either GABAergic or glycinergic synapses becomes detectable only after postnatal days 15 and 21, respectively. Using mice older than postnatal day 21, we also characterized the plastic changes in glycinergic transmission resulting from the inactivation of the GlyR alpha3 subunit gene, a key player in inflammatory pain pathways. This allowed us to demonstrate that synapses containing GlyR alpha3 contribute in large part to synaptic inhibition in lamina II. In Glra3 knockout mice, we found that synaptic currents at the remaining glycinergic synapses, containing GlyR alpha1, showed faster decay kinetics with unchanged amplitudes but increased frequency. These findings explain the absence of any basal nociceptive hypersensitivity in Glra3 knockout mice, as GlyR alpha1 is still available for mediating synaptic inhibition at lamina II synapses, but cannot be modulated by the prostaglandin-E-prostanoid type 2 (EP2) receptor-protein kinase A signalling cascade. Our results clearly demonstrate that presynaptic GABA/glycine release properties are influenced by the nature and complexity of postsynaptic inhibitory receptor subtypes.

Using multiple mini interviews as a pre-screening tool for medical student candidates completing international health electives.

There continues to be an increase in the number of learners who participate in international health electives (IHEs). However, not all learners enter IHEs with the same level of knowledge, attitude, and previous experience, which puts undue burden on host supervisors and poses risks to student and patient safety. The Multiple Mini-Interview (MMI) is a technique that has become a popular method for undergraduate and postgraduate-level health science admissions programs. This paper describes the MMI process used by our program to screen first-year medical students applying for pre-clinical IHEs. Two country-specific cases were developed to assess non-cognitive skills. One hundred percent (100%) of the students (n = 48) and interviewers (n = 10) who participated in MMIs completed anonymous surveys on their experience. The majority of students rated the scenarios as realistic (>90%); 96% found the MMI format fair and balanced; 96% of students felt that they were able to clearly articulate their thoughts; 75% of students stated that they had a general understanding of how the MMIs worked; only 33% of students would have preferred a traditional one-to-one interview. Feedback from both interviewers and students was positive toward the MMI experience, and no students were identified as unfit for participation. Ultimately, 43 students participated in pre-clinical IHEs in 2016. In this paper, we will outline our MMI process, detail shortcomings, and discuss our next steps to screen medical students for IHEs.

Instrumentation for Reliably Determining Porous Silicon Photoluminescence Responses to Gaseous Analyte Vapors.

We report new instrumentation for rapidly and reliably measuring the temperature-dependent photoluminescence response from porous silicon as a function of analyte vapor concentration. The new system maintains the porous silicon under inert conditions and it allows on-the-fly steady-state and time-resolved photoluminescence intensity and hyper-spectral measurements between 293 K and 450 K. The new system yields reliable data at least 100-fold faster in comparison to previous instrument platforms.

Contact Pin-Printing onto Porous Silicon for Creating Microarrays with High Chemical Diversity.

We explore the size and spatial microheterogeneity of contact pin-printed spots formed on porous silicon (pSi). Glycerol was contact printed at room temperature onto as-prepared, hydrogen-passivated pSi (ap-pSi) using 50 or 200 µm diameter solid pins. The pSi was then subjected to a strong oxidizing environment (gaseous O3) and washed to remove the glycerol masks. The glycerol-free regions were converted to oxidized pSi (ox-pSi); the glycerol-coated regions were protected from O3, but not entirely. The final array is described as circularly shaped "ap-pSi" regions on a field of ox-pSi. When comparing the areas outside and inside the glycerol-masked pSi spots, one finds dramatic differences in the Si-O-Si, SiHx (x = 1-3) and OySiHx (y, x = 1-3) levels with a spatially dependent continuum of compositions across the spot diameter. Experimental conditions could be adjusted to tune the final ap-pSi spot diameter and edge widths from 90 µm to 520 µm and 20 µm to 130 µm, respectively. The resulting ap-pSi spot diameter is explained by using molecular kinetic theory and time-dependent glycerol imbibement into the pSi within a one-dimensional Darcy's law model.

Genetics of Skeletal Evolution in Unusually Large Mice from Gough Island.

Organisms on islands often undergo rapid morphological evolution, providing a platform for understanding mechanisms of phenotypic change. Many examples of evolution on islands involve the vertebrate skeleton. Although the genetic basis of skeletal variation has been studied in laboratory strains, especially in the house mouse Mus musculus domesticus, the genetic determinants of skeletal evolution in natural populations remain poorly understood. We used house mice living on the remote Gough Island-the largest wild house mice on record-to understand the genetics of rapid skeletal evolution in nature. Compared to a mainland reference strain from the same subspecies (WSB/EiJ), the skeleton of Gough Island mice is considerably larger, with notable expansions of the pelvis and limbs. The Gough Island mouse skeleton also displays changes in shape, including elongations of the skull and the proximal vs. distal elements in the limbs. Quantitative trait locus (QTL) mapping in a large F2 intercross between Gough Island mice and WSB/EiJ reveals hundreds of QTL that control skeletal dimensions measured at 5, 10, and/or 16 weeks of age. QTL exhibit modest, mostly additive effects, and Gough Island alleles are associated with larger skeletal size at most QTL. The QTL with the largest effects are found on a few chromosomes and affect suites of skeletal traits. Many of these loci also colocalize with QTL for body weight. The high degree of QTL colocalization is consistent with an important contribution of pleiotropy to skeletal evolution. Our results provide a rare portrait of the genetic basis of skeletal evolution in an island population and position the Gough Island mouse as a model system for understanding mechanisms of rapid evolution in nature.

Genetics of Rapid and Extreme Size Evolution in Island Mice.

Organisms on islands provide a revealing window into the process of adaptation. Populations that colonize islands often evolve substantial differences in body size from their mainland relatives. Although the ecological drivers of this phenomenon have received considerable attention, its genetic basis remains poorly understood. We use house mice (subspecies: Mus musculus domesticus) from remote Gough Island to provide a genetic portrait of rapid and extreme size evolution. In just a few hundred generations, Gough Island mice evolved the largest body size among wild house mice from around the world. Through comparisons with a smaller-bodied wild-derived strain from the same subspecies (WSB/EiJ), we demonstrate that Gough Island mice achieve their exceptional body weight primarily by growing faster during the 6 weeks after birth. We use genetic mapping in large F(2) intercrosses between Gough Island mice and WSB/EiJ to identify 19 quantitative trait loci (QTL) responsible for the evolution of 16-week weight trajectories: 8 QTL for body weight and 11 QTL for growth rate. QTL exhibit modest effects that are mostly additive. We conclude that body size evolution on islands can be genetically complex, even when substantial size changes occur rapidly. In comparisons to published studies of laboratory strains of mice that were artificially selected for divergent body sizes, we discover that the overall genetic profile of size evolution in nature and in the laboratory is similar, but many contributing loci are distinct. Our results underscore the power of genetically characterizing the entire growth trajectory in wild populations and lay the foundation necessary for identifying the mutations responsible for extreme body size evolution in nature.

Hydrophilic polyurethane matrix promotes chondrogenesis of mesenchymal stem cells.

Segmental polyurethanes exhibit biphasic morphology and can control cell fate by providing distinct matrix guided signals to increase the chondrogenic potential of mesenchymal stem cells (MSCs). Polyethylene glycol (PEG) based hydrophilic polyurethanes can deliver differential signals to MSCs through their matrix phases where hard segments are cell-interactive domains and PEG based soft segments are minimally interactive with cells. These coordinated communications can modulate cell-matrix interactions to control cell shape and size for chondrogenesis. Biphasic character and hydrophilicity of polyurethanes with gel like architecture provide a synthetic matrix conducive for chondrogenesis of MSCs, as evidenced by deposition of cartilage-associated extracellular matrix. Compared to monophasic hydrogels, presence of cell interactive domains in hydrophilic polyurethanes gels can balance cell-cell and cell-matrix interactions. These results demonstrate the correlation between lineage commitment and the changes in cell shape, cell-matrix interaction, and cell-cell adhesion during chondrogenic differentiation which is regulated by polyurethane phase morphology, and thus, represent hydrophilic polyurethanes as promising synthetic matrices for cartilage regeneration.

Kinematic gait analysis of the canine thoracic limb using a six degrees of freedom marker set. Study in normal Labrador Retrievers and Labrador Retrievers with medial coronoid process disease.

OBJECTIVES: To determine if the use of a six degrees of freedom marker set would allow new kinematic data of the canine thoracic limbs to be calculated. To identify any significant differences in thoracic limb gait patterns in all planes of motion, between the normal canine population and patients with confirmed medial coronoid disease (MCD). METHOD: Two groups of dogs were selected representing the normal Labrador Retriever population (n = 13) and Labrador Retrievers with confirmed MCD (n = 13). Normal dogs had "normal" hip and elbow radiographic scores in line with the International Elbow Working Group and British Veterinary Association guidelines. Medial coronoid disease was confirmed using arthroscopy after kinematic analysis was performed with a six degrees of freedom marker set. RESULTS: The diseased elbow was nine degrees more extended between 43%-55% of the gait cycle and 16° more supinated prior, early during and after foot strike. The antebrachium was nine degrees more supinated during foot strike and three degrees more abducted during early stance. None of the other parameters were significantly different. CLINICAL SIGNIFICANCE: The use of a six degrees of freedom marker set made it possible for the elbow and antebrachium to be reliably tracked in more than one plane of motion. Significant differences were identified between the normal canine population and those affected by MCD. These data may help elucidate biomechanical factors contributing to aetiopathogenesis of MCD.