Predictors for work participation of people with visual impairments: A systematic review and meta-analysis.

INTRODUCTION: The aim of this systematic review and meta-analysis was to assess factors associated with work participation in people with visual impairments and to explore how these factors may have changed over time. METHOD: A comprehensive search of PubMed, Embase.com, EBSCO/APA PsycInfo, EBSCO/CINAHL and EBSCO/ERIC from database inception to 1 April 2022 was performed. We included studies with cross-sectional design, case-control, case-series or cohort design, involving visually impaired working-age adults with at least moderate visual impairment, and evaluated the association between visual impairment and work participation. Studies involving participants with deaf-blindness or multiple disabilities were excluded. We assessed study quality (Newcastle-Ottawa Scale [NOS]), examined between-study heterogeneity and performed subgroup analyses. The study protocol was registered in PROSPERO, CRD42021241076. RESULTS: Of 13,585 records, 57 articles described 55 studies including 1,326,091 participants from mostly high-income countries. Sociodemographic factors associated with employment included higher education (odds ratio [OR] 3.34, 95% confidence interval [CI] 2.47 to 4.51, I2 0%), being male (OR 1.59, 95% CI 1.37 to 1.84, I2 95%), having a partner (OR 1.73, 95% CI 1.12 to 2.67, I2 34%), white ethnicity (OR 1.36, 95% CI 1.07 to 1.74, I2 0%) and having financial assistance (OR 0.38, 95% CI 0.26 to 0.55, I2 85%). Disease-related factors included worse visual impairment (OR 0.61, 95% CI 0.46 to 0.80, I2 98%) or having additional disabilities (OR 0.55, 95% CI 0.49 to 0.62, I2 16%). Intervention-related factors included mobility aid utilisation (OR 0.35, 95% CI 0.10 to 1.18, I2 94%). A potential moderating effect of time period and geographical region was observed for some factors. Study quality (NOS) was rated moderate to high. CONCLUSION: Several sociodemographic and disease related factors were associated with employment status. However, the results should be interpreted with caution because of overall high heterogeneity. Future research should focus on the role of workplace factors, technological adjustments and vocational rehabilitation services on work participation.

Anthracycline-induced cytotoxicity in the GL261 glioma model system.

Glioblastoma (GBM) is a lethal astrocyte-derived tumor that is currently treated with a multi-modal approach of surgical resection, radiotherapy, and temozolomide-based chemotherapy. Alternatives to current therapies are urgently needed as its prognosis remains poor. Anthracyclines are a class of compounds that show great potential as GBM chemotherapeutic agents and are widely used to treat solid tumors outside the central nervous system. Here we investigate the cytotoxic effects of doxorubicin and other anthracyclines on GL261 glioma tumor cells in anticipation of novel anthracycline-based CNS therapies. Three methods were used to quantify dose-dependent effects of anthracyclines on adherent GL261 tumor cells, a murine cell-based model of GBM. MTT assays quantified anthracycline effects on cell viability, comet assays examined doxorubicin genotoxicity, and flow cytometry with Annexin V/PI staining characterized doxorubicin-induced apoptosis and necrosis. Dose-dependent reductions in GL261 cell viability were found in cells treated with doxorubicin (EC50 = 4.9 µM), epirubicin (EC50 = 5.9 µM), and idarubicin (EC50 = 4.4 µM). Comet assays showed DNA damage following doxorubicin treatments, peaking at concentrations of 1.0 µM and declining after 25 µM. Lastly, flow cytometric analysis of doxorubicin-treated cells showed dose-dependent induction of apoptosis (EC50 = 5.2 µM). Together, these results characterized the cytotoxic effects of anthracyclines on GL261 glioma cells. We found dose-dependent apoptotic induction; however at high concentrations we find that cell death is likely necrotic. Our results support the continued exploration of anthracyclines as compounds with significant potential for improved GBM treatments.

Building a biomedical pipeline: the impact of the Idaho IDeA INBRE summer research experience at a primarily undergraduate institution.

Idaho Institutional Development Award (IDeA) Network for Biomedical Research Excellence (INBRE) aims to build biomedical research capacity and enhance the scientific and technology knowledge of the Idaho workforce. A key INBRE Program at The College of Idaho, a primarily undergraduate institution of 1,100 students, is a 10-wk summer fellows research experience. This report documents outcomes from 2005 to present, including demographic trends, faculty and student research productivity, self-reported gains, educational attainment, and career outcomes. Of 103 participants, 83.7% were from Idaho, 26.7% from rural areas, and 23.9% first-generation college students. Faculty and student research productivity (conference presentations and peer-reviewed publications) increased threefold. We found that 91.4% of fellows entered a scientific- or healthcare-related career and that 70.7% completed or are currently enrolled in postgraduate training (51.7% doctoral and 19.0% master's level). Anonymous surveys were uniformly positive, with gains in self-confidence and independent laboratory work. Open-ended responses indicated students valued mentoring efforts and improved awareness of scientific opportunities and competitive preparation for postgraduate training. Lastly, we observed that student research involvement increased college-wide during the award period. These data suggest that the summer fellows program is successfully meeting National Institutes of Health IDeA goals and serving as a pipeline to future health research careers and a scientifically trained Idaho workforce.

Management of Peutz-Jeghers Syndrome in Children and Adolescents: A Position Paper From the ESPGHAN Polyposis Working Group.

Peutz-Jeghers syndrome (PJS) is a well-described inherited syndrome, characterized by the development of gastrointestinal polyps, and characteristic mucocutaneous freckling. Development of small bowel intestinal polyps may lead to intussusception in children may require emergency laparotomy with potential loss of bowel. Gastrointestinal polyps may lead to bleeding and anemia. This European Society for Paediatric Gastroenterology Hepatology and Nutrition position paper provides a guide for diagnosis, assessment, and management of PJS in children and adolescents and guidance on avoiding complications from PJS or from the endoscopic procedures performed on these patients.This is the first position paper regarding PJS published by European Society for Paediatric Gastroenterology Hepatology and Nutrition. Literature from PubMed, Medline, and Embase was reviewed and in the absence of evidence, recommendations reflect the opinion of pediatric and adult experts involved in the care of polyposis syndromes. Because many of the studies that form the basis for the recommendations were descriptive and/or retrospective in nature, some of the recommendations are based on expert opinion. This position paper will be helpful in the appropriate management and timing of procedures in children and adolescents with PJS.

GL261 glioma tumor cells respond to ATP with an intracellular calcium rise and glutamate release.

Glioblastoma (GBM) is an aggressive brain cancer with an average survival rate of 15 months. The composition of the GBM tumor microenvironment-its pH, the presence of growth and immune factors, neurotransmitters, and gliotransmitters-plays an important role in GBM pathophysiology and facilitates tumor survival and growth. In particular, GBM tumor cells produce glutamate, which is toxic to healthy tissue and is associated with increased tumor invasion into adjacent brain regions. The conditions that lead to this excitotoxic release of glutamate are not completely understood. Previous studies have demonstrated that extracellular ATP is present at high levels in the tumor microenvironment, and that ATP stimulates the release of glutamate from astrocytes in culture. Here we examine the functional effects of extracellular ATP on the GL261 cell line, a model system for high-grade astrocytomas such as GBM. We show that treatment with ATP leads to an immediate, dose-dependent influx of calcium into the cell that is partially inhibited by an antagonist (o-ATP) of the ionotropic ATP receptor P2X7. In addition, GL261 cells respond to extracellular ATP with a dose-dependent release of glutamate. Consistent with other reports, we find that ATP is toxic to GL261 cells at high concentrations. Together, these results provide insight into the mechanisms responsible for glutamate production by tumor cells and inform future studies that will identify how the GBM tumor microenvironment facilitates tumor invasion into healthy areas of the brain.

Live-cell calcium imaging of adherent and non-adherent GL261 cells reveals phenotype-dependent differences in drug responses.

BACKGROUND: The tumor-derived GL261 cell line is used as a model for studying glioblastoma and other high-grade gliomas, and can be cultured adherently or as free-floating aggregates known as neurospheres. These different culture conditions give rise to distinct phenotypes, with increased tumorigenicity displayed by neurosphere-cultured cells. An important technique for understanding GL261 pathobiology is live cell fluorescent imaging of intracellular calcium. However, live cell imaging of GL261 neurospheres presents a technical challenge, as experimental manipulations where drugs are added to the extracellular media cause the cells to move during analysis. Here we present a method to immobilize GL261 neurospheres with low melting point agarose for calcium imaging using the fluorescent calcium sensor fura-2. METHODS: GL261 cells were obtained from the NCI-Frederick Cancer Research Tumor Repository and cultured as adherent cells or induced to form neurospheres by placing freshly trypsinized cells into serum-free media containing fibroblast growth factor 2, epidermal growth factor, and B-27 supplement. Prior to experiments, adherent cells were loaded with fura-2 and cultured on 8-well chamber slides. Non-adherent neurospheres were first loaded with fura-2, placed in droplets onto an 8-well chamber slide, and finally covered with a thin layer of low melting point agarose to immobilize the cells. Ratiometric pseudocolored images were obtained during treatment with ATP, capsaicin, or vehicle control. Cells were marked as responsive if fluorescence levels increased more than 30% above baseline. Differences between treatment groups were tested using Student's t-tests and one-way ANOVA. RESULTS: We found that cellular responses to pharmacological treatments differ based on cellular phenotype. Adherent cells and neurospheres both responded to ATP with a rise in intracellular calcium. Notably, capsaicin treatment led to robust responses in GL261 neurospheres but not adherent cells. CONCLUSIONS: We demonstrate the use of low melting point agarose for immobilizing GL261 cells, a method that is broadly applicable to any cell type cultured in suspension, including acutely trypsinized cells and primary tumor cells. Our results indicate that it is important to consider GL261 phenotype (adherent or neurosphere) when interpreting data regarding physiological responses to experimental compounds.

Genetic modifiers of abnormal organelle biogenesis in a Drosophila model of BLOC-1 deficiency.

Biogenesis of lysosome-related organelles complex 1 (BLOC-1) is a protein complex formed by the products of eight distinct genes. Loss-of-function mutations in two of these genes, DTNBP1 and BLOC1S3, cause Hermansky-Pudlak syndrome, a human disorder characterized by defective biogenesis of lysosome-related organelles. In addition, haplotype variants within the same two genes have been postulated to increase the risk of developing schizophrenia. However, the molecular function of BLOC-1 remains unknown. Here, we have generated a fly model of BLOC-1 deficiency. Mutant flies lacking the conserved Blos1 subunit displayed eye pigmentation defects due to abnormal pigment granules, which are lysosome-related organelles, as well as abnormal glutamatergic transmission and behavior. Epistatic analyses revealed that BLOC-1 function in pigment granule biogenesis requires the activities of BLOC-2 and a putative Rab guanine-nucleotide-exchange factor named Claret. The eye pigmentation phenotype was modified by misexpression of proteins involved in intracellular protein trafficking; in particular, the phenotype was partially ameliorated by Rab11 and strongly enhanced by the clathrin-disassembly factor, Auxilin. These observations validate Drosophila melanogaster as a powerful model for the study of BLOC-1 function and its interactions with modifier genes.

A tyrosine-based motif localizes a Drosophila vesicular transporter to synaptic vesicles in vivo.

Vesicular neurotransmitter transporters must localize to synaptic vesicles (SVs) to allow regulated neurotransmitter release at the synapse. However, the signals required to localize vesicular proteins to SVs in vivo remain unclear. To address this question we have tested the effects of mutating proposed trafficking domains in Drosophila orthologs of the vesicular monoamine and glutamate transporters, DVMAT-A and DVGLUT. We show that a tyrosine-based motif (YXXY) is important both for DVMAT-A internalization from the cell surface in vitro, and localization to SVs in vivo. In contrast, DVGLUT deletion mutants that lack a putative C-terminal trafficking domain show more modest defects in both internalization in vitro and trafficking to SVs in vivo. Our data show for the first time that mutation of a specific trafficking motif can disrupt localization to SVs in vivo and suggest possible differences in the sorting of VMATs versus VGLUTs to SVs at the synapse.

Increased vesicular glutamate transporter expression causes excitotoxic neurodegeneration.

Increases in vesicular glutamate transporter (VGLUT) levels are observed after a variety of insults including hypoxic injury, stress, methamphetamine treatment, and in genetic seizure models. Such overexpression can cause an increase in the amount of glutamate released from each vesicle, but it is unknown whether this is sufficient to induce excitotoxic neurodegeneration. Here we show that overexpression of the Drosophila vesicular glutamate transporter (DVGLUT) leads to excess glutamate release, with some vesicles releasing several times the normal amount of glutamate. Increased DVGLUT expression also leads to an age-dependent loss of motor function and shortened lifespan, accompanied by a progressive neurodegeneration in the postsynaptic targets of the DVGLUT-overexpressing neurons. The early onset lethality, behavioral deficits, and neuronal pathology require overexpression of a functional DVGLUT transgene. Thus overexpression of DVGLUT is sufficient to generate excitotoxic neuropathological phenotypes and therefore reducing VGLUT levels after nervous system injury or stress may mitigate further damage.

Fast flies take a quantum leap.

Presynaptic regulation of quantal size is an appealing mechanism for changing synapse strength. In this issue of Neuron, Steinert et al. describe an activity-dependent increase in synapse strength mediated by the formation and release of large synaptic vesicles at the Drosophila neuromuscular junction.

A single vesicular glutamate transporter is sufficient to fill a synaptic vesicle.

Quantal size is the postsynaptic response to the release of a single synaptic vesicle and is determined in part by the amount of transmitter within that vesicle. At glutamatergic synapses, the vesicular glutamate transporter (VGLUT) fills vesicles with glutamate. While elevated VGLUT expression increases quantal size, the minimum number of transporters required to fill a vesicle is unknown. In Drosophila DVGLUT mutants, reduced transporter levels lead to a dose-dependent reduction in the frequency of spontaneous quantal release with no change in quantal size. Quantal frequency is not limited by vesicle number or impaired exocytosis. This suggests that a single functional unit of transporter is both necessary and sufficient to fill a vesicle to completion and that vesicles without DVGLUT are empty. Consistent with the presence of empty vesicles, at dvglut mutant synapses synaptic vesicles are smaller, suggesting that vesicle filling and/or transporter level is an important determinant of vesicle size.

PP2A and GSK-3beta act antagonistically to regulate active zone development.

The synapse is composed of an active zone apposed to a postsynaptic cluster of neurotransmitter receptors. Each Drosophila neuromuscular junction comprises hundreds of such individual release sites apposed to clusters of glutamate receptors. Here, we show that protein phosphatase 2A (PP2A) is required for the development of structurally normal active zones opposite glutamate receptors. When PP2A is inhibited presynaptically, many glutamate receptor clusters are unapposed to Bruchpilot (Brp), an active zone protein required for normal transmitter release. These unapposed receptors are not due to presynaptic retraction of synaptic boutons, since other presynaptic components are still apposed to the entire postsynaptic specialization. Instead, these data suggest that Brp localization is regulated at the level of individual release sites. Live imaging of glutamate receptors demonstrates that this disruption to active zone development is accompanied by abnormal postsynaptic development, with decreased formation of glutamate receptor clusters. Remarkably, inhibition of the serine-threonine kinase GSK-3beta completely suppresses the active zone defect, as well as other synaptic morphology phenotypes associated with inhibition of PP2A. These data suggest that PP2A and GSK-3beta function antagonistically to control active zone development, providing a potential mechanism for regulating synaptic efficacy at a single release site.

Drosophila vesicular monoamine transporter mutants can adapt to reduced or eliminated vesicular stores of dopamine and serotonin.

Physiologic and pathogenic changes in amine release induce dramatic behavioral changes, but the underlying cellular mechanisms remain unclear. To investigate these adaptive processes, we have characterized mutations in the Drosophila vesicular monoamine transporter (dVMAT), which is required for the vesicular storage of dopamine, serotonin, and octopamine. dVMAT mutant larvae show reduced locomotion and decreased electrical activity in motoneurons innervating the neuromuscular junction (NMJ) implicating central amines in the regulation of these activities. A parallel increase in evoked glutamate release by the motoneuron is consistent with a homeostatic adaptation at the NMJ. Despite the importance of aminergic signaling for regulating locomotion and other behaviors, adult dVMAT homozygous null mutants survive under conditions of low population density, thus allowing a phenotypic characterization of adult behavior. Homozygous mutant females are sterile and show defects in both egg retention and development; males also show reduced fertility. Homozygotes show an increased attraction to light but are mildly impaired in geotaxis and escape behaviors. In contrast, heterozygous mutants show an exaggerated escape response. Both hetero- and homozygous mutants demonstrate an altered behavioral response to cocaine. dVMAT mutants define potentially adaptive responses to reduced or eliminated aminergic signaling and will be useful to identify the underlying molecular mechanisms.

Modification of a hydrophobic layer by a point mutation in syntaxin 1A regulates the rate of synaptic vesicle fusion.

Both constitutive secretion and Ca(2+)-regulated exocytosis require the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. At present, little is known about how the SNARE complexes mediating these two distinct pathways differ in structure. Using the Drosophila neuromuscular synapse as a model, we show that a mutation modifying a hydrophobic layer in syntaxin 1A regulates the rate of vesicle fusion. Syntaxin 1A molecules share a highly conserved threonine in the C-terminal +7 layer near the transmembrane domain. Mutation of this threonine to isoleucine results in a structural change that more closely resembles those found in syntaxins ascribed to the constitutive secretory pathway. Flies carrying the I254 mutant protein have increased levels of SNARE complexes and dramatically enhanced rate of both constitutive and evoked vesicle fusion. In contrast, overexpression of the T254 wild-type protein in neurons reduces vesicle fusion only in the I254 mutant background. These results are consistent with molecular dynamics simulations of the SNARE core complex, suggesting that T254 serves as an internal brake to dampen SNARE zippering and impede vesicle fusion, whereas I254 favors fusion by enhancing intermolecular interaction within the SNARE core complex.

Design and construction of a two-temperature preference behavioral assay for undergraduate neuroscience laboratories.

Behavioral assays in the undergraduate neuroscience laboratory are useful for illustrating a variety of physiological concepts. An example is homeostatic temperature regulation (thermoregulation). Many model organisms, from flies to mice, regulate internal temperatures in part by moving to suitable climates (thermotaxis). A particularly reliable method of quantifying temperature-dependent thermotactic behaviors is the two-temperature preference behavioral assay. In this preparation, an organism is free to move between two temperature-controlled surfaces, thus revealing its preferred thermal environment. Here we present the design and construction of a two-temperature preference assay chamber. The device uses Peltier-based thermoelectric modules (TECs) for heating and cooling, and is capable of precision control of temperatures from -5ºC to 60ºC. Our approach can be easily adapted for use in a variety of physiological and behavioral assays that require precise temperature control over a wide range of temperatures.

Diversity in the neural circuitry of cold sensing revealed by genetic axonal labeling of transient receptor potential melastatin 8 neurons.

Sensory nerves detect an extensive array of somatosensory stimuli, including environmental temperatures. Despite activating only a small cohort of sensory neurons, cold temperatures generate a variety of distinct sensations that range from pleasantly cool to painfully aching, prickling, and burning. Psychophysical and functional data show that cold responses are mediated by both C- and A delta-fibers with separate peripheral receptive zones, each of which likely provides one or more of these distinct cold sensations. With this diversity in the neural basis for cold, it is remarkable that the majority of cold responses in vivo are dependent on the cold and menthol receptor transient receptor potential melastatin 8 (TRPM8). TRPM8-null mice are deficient in temperature discrimination, detection of noxious cold temperatures, injury-evoked hypersensitivity to cold, and nocifensive responses to cooling compounds. To determine how TRPM8 plays such a critical yet diverse role in cold signaling, we generated mice expressing a genetically encoded axonal tracer in TRPM8 neurons. Based on tracer expression, we show that TRPM8 neurons bear the neurochemical hallmarks of both C- and A delta-fibers, and presumptive nociceptors and non-nociceptors. More strikingly, TRPM8 axons diffusely innervate the skin and oral cavity, terminating in peripheral zones that contain nerve endings mediating distinct perceptions of innocuous cool, noxious cold, and first- and second-cold pain. These results further demonstrate that the peripheral neural circuitry of cold sensing is cellularly and anatomically complex, yet suggests that cold fibers, caused by the diverse neuronal context of TRPM8 expression, use a single molecular sensor to convey a wide range of cold sensations.

Case of acute paraspinal pyomyositis in an elderly diabetic secondary to spread from urinary tract infection.

A 73-year-old woman with medical history of diabetes and hypertension presented with right-sided back pain and night sweats of 1 month duration. On physical examination, there was costovertebral angle tenderness and her urinalysis was indicative for urinary tract infection. She was admitted and managed with intravenous antibiotics. On initial imaging, there was a right-sided retroperitoneal mass adjacent to right kidney. This was investigated further with MRI, which showed diffuse inflammation of right paraspinal muscles with two loculated abscesses. The abscesses were aspirated and the culture sent grew Streptococcus agalactiae (Group B Streptococcus) and the patient was treated with 6-week course of intravenous antibiotics.

Extensive hippocampal demyelination in multiple sclerosis.

Memory impairment is especially prominent within the spectrum of cognitive deficits in multiple sclerosis (MS), and a crucial role for hippocampal pathology may therefore be expected in this disease. This study is the first to systematically assess hippocampal demyelination in MS. Hippocampal tissue samples of 19 chronic MS cases and 7 controls with non-neurologic disease were stained immunohistochemically for myelin proteolipid protein. Subsequently, number, location, and size of demyelinated lesions were assessed. Furthermore, the specimens were stained for HLA-DR to investigate microglia/macrophage activity. An unexpectedly high number of lesions (n = 37) was found in 15 of the 19 MS cases. Mixed intrahippocampal-perihippocampal lesions, which were more often found in cases with cognitive decline, were large and did not respect anatomical borders. Moderate microglial activation was frequently observed at the edges of these mixed lesions. Isolated intrahippocampal lesions were also frequently found. These were smaller than the mixed lesions and had a specific anatomical predilection: the cornu ammonis 2 subregion and the hilus of the dentate gyrus were consistently spared. Microglial activation was rare in isolated intrahippocampal lesions. Our results indicate that hippocampal demyelination is frequent and extensive in MS and that anatomical localization, size, and inflammatory activity vary for different lesion types.

Mice left out in the cold: commentary on the phenotype of TRPM8-nulls.

Detection of innocuous temperatures allows an organism to select an appropriate environmental climate, while the ability to recognize noxious temperature extremes warns of impending tissue damage. For temperatures considered cold, the menthol receptor TRPM8 is activated when temperatures drop below approximately 26 degrees C, thus making it an intriguing candidate as the molecular mediator of cold perception. However, confirmation of this hypothesis in vivo has eluded researchers until recently. Three independent research groups have reported that mice lacking this single gene are severely impaired in their ability to detect cold temperatures. Remarkably, these animals are deficient in many diverse aspects of cold signaling, including cool and noxious cold perception, injury-evoked sensitization to cold, and cooling-induced analgesia. These animals provide a great deal of insight into the molecular signaling pathways that participate in the detection of cold and painful stimuli.

Increased expression of the Drosophila vesicular glutamate transporter leads to excess glutamate release and a compensatory decrease in quantal content.

Quantal size is a fundamental parameter controlling the strength of synaptic transmission. The transmitter content of synaptic vesicles is one mechanism that can affect the physiological response to the release of a single vesicle. At glutamatergic synapses, vesicular glutamate transporters (VGLUTs) are responsible for filling synaptic vesicles with glutamate. To investigate how VGLUT expression can regulate synaptic strength in vivo, we have identified the Drosophila vesicular glutamate transporter, which we name DVGLUT. DVGLUT mRNA is expressed in glutamatergic motoneurons and a large number of interneurons in the Drosophila CNS. DVGLUT protein resides on synaptic vesicles and localizes to the presynaptic terminals of all known glutamatergic neuromuscular junctions as well as to synapses throughout the CNS neuropil. Increasing the expression of DVGLUT in motoneurons leads to an increase in quantal size that is accompanied by an increase in synaptic vesicle volume. At synapses confronted with increased glutamate release from each vesicle, there is a compensatory decrease in the number of synaptic vesicles released that maintains normal levels of synaptic excitation. These results demonstrate that (1) expression of DVGLUT determines the size and glutamate content of synaptic vesicles and (2) homeostatic mechanisms exist to attenuate the excitatory effects of excess glutamate release.