Hepatitis B virus e antigen induces atypical metabolism and differentially regulates programmed cell deaths of macrophages.

Macrophages can undergo M1-like proinflammatory polarization with low oxidative phosphorylation (OXPHOS) and high glycolytic activities or M2-like anti-inflammatory polarization with the opposite metabolic activities. Here we show that M1-like macrophages induced by hepatitis B virus (HBV) display high OXPHOS and low glycolytic activities. This atypical metabolism induced by HBV attenuates the antiviral response of M1-like macrophages and is mediated by HBV e antigen (HBeAg), which induces death receptor 5 (DR5) via toll-like receptor 4 (TLR4) to induce death-associated protein 3 (DAP3). DAP3 then induces the expression of mitochondrial genes to promote OXPHOS. HBeAg also enhances the expression of glutaminases and increases the level of glutamate, which is converted to α-ketoglutarate, an important metabolic intermediate of the tricarboxylic acid cycle, to promote OXPHOS. The induction of DR5 by HBeAg leads to apoptosis of M1-like and M2-like macrophages, although HBeAg also induces pyroptosis of the former. These findings reveal novel activities of HBeAg, which can reprogram mitochondrial metabolism and trigger different programmed cell death responses of macrophages depending on their phenotypes to promote HBV persistence.

Chromophore supply modulates cone function and survival in retinitis pigmentosa mouse models.

Retinitis pigmentosa (RP) is an ocular disease characterized by the loss of night vision, followed by the loss of daylight vision. Daylight vision is initiated in the retina by cone photoreceptors, which are gradually lost in RP, often as bystanders in a disease process that initiates in their neighboring rod photoreceptors. Using physiological assays, we investigated the timing of cone electroretinogram (ERG) decline in RP mouse models. A correlation between the time of loss of the cone ERG and the loss of rods was found. To investigate a potential role of the visual chromophore supply in this loss, mouse mutants with alterations in the regeneration of the retinal chromophore, 11-cis retinal, were examined. Reducing chromophore supply via mutations in Rlbp1 or Rpe65 resulted in greater cone function and survival in a RP mouse model. Conversely, overexpression of Rpe65 and Lrat, genes that can drive the regeneration of the chromophore, led to greater cone degeneration. These data suggest that abnormally high chromophore supply to cones upon the loss of rods is toxic to cones, and that a potential therapy in at least some forms of RP is to slow the turnover and/or reduce the level of visual chromophore in the retina.

Organ- and Cell-Selective Delivery of mRNA In Vivo Using Guanidinylated Serinol Charge-Altering Releasable Transporters.

Selective RNA delivery is required for the broad implementation of RNA clinical applications, including prophylactic and therapeutic vaccinations, immunotherapies for cancer, and genome editing. Current polyanion delivery relies heavily on cationic amines, while cationic guanidinium systems have received limited attention due in part to their strong polyanion association, which impedes intracellular polyanion release. Here, we disclose a general solution to this problem in which cationic guanidinium groups are used to form stable RNA complexes upon formulation but at physiological pH undergo a novel charge-neutralization process, resulting in RNA release. This new delivery system consists of guanidinylated serinol moieties incorporated into a charge-altering releasable transporter (GSer-CARTs). Significantly, systematic variations in structure and formulation resulted in GSer-CARTs that exhibit highly selective mRNA delivery to the lung (∼97%) and spleen (∼98%) without targeting ligands. Illustrative of their breadth and translational potential, GSer-CARTs deliver circRNA, providing the basis for a cancer vaccination strategy, which in a murine model resulted in antigen-specific immune responses and effective suppression of established tumors.

VISUAL OUTCOMES AFTER INTERNAL LIMITING MEMBRANE PEELING VERSUS FLAP IN THE CLOSURE OF FULL-THICKNESS MACULAR HOLES.

PURPOSE: To examine postoperative outcomes of internal limiting membrane peeling (ILMP) versus flap (ILMF) in the closure of full-thickness macular holes. METHODS: Retrospective chart review of patients who underwent pars plana vitrectomy and gas tamponade with ILMP or ILMF to close full-thickness macular hole at the Atrium Health Wake Forest Baptist from January 2012 to October 2022 with at least 3 months follow-up. Main outcome measures were type 1 primary full-thickness macular hole closure and postoperative best-corrected visual acuity in mean logMAR. RESULTS: One hundred thirty and 30 eyes underwent ILMP and ILMF, respectively. There were no significant differences in baseline characteristics between the groups. Ninety-six percent of ILMP eyes and 90% of ILMF eyes achieved primary hole closure ( P = 0.29). Among all eyes with primary hole closure, best-corrected visual acuity at 1 year was not different between the groups, but when stratified by lens status, it was superior in the ILMP versus ILMF group in pseudophakic eyes: the estimated least-squares mean best-corrected visual acuity (Snellen equivalent) (95% confidence interval) was 0.42 (20/50) (0.34, 0.49) in the ILMP group and 0.71 (20/100) (0.50, 0.92) in the ILMF group. CONCLUSION: Internal limiting membrane peeling and ILMF techniques yielded similarly high full-thickness macular hole closure rates. In pseudophakic eyes with primary hole closure, ILMF eyes had worse best-corrected visual acuity at 1 year.

Path to autonomous soil sampling and analysis by ground-based robots.

Good site characterization is essential for the selection of remediation alternatives for impacted soils. The value of site characterization is critically dependent on the quality and quantity of the data collected. Current methods for characterizing impacted soils rely on expensive manual sample collection and off-site analysis. However, recent advances in terrestrial robotics and artificial intelligence offer a potentially revolutionary set of tools and methods that will help to autonomously explore natural environments, select sample locations with the highest value of information, extract samples, and analyze the data in real-time without exposing humans to potentially hazardous conditions. A fundamental challenge to realizing this potential is determining how to design an autonomous system for a given investigation with many, and often conflicting design criteria. This work presents a novel design methodology to navigate these criteria. Specifically, this methodology breaks the system into four components - sensing, sampling, mobility, and autonomy - and connects design variables to the investigation objectives and constraints. These connections are established for each component through a survey of existing technology, discussion of key technical challenges, and highlighting conditions where generality can promote multi-application deployment. An illustrative example of this design process is presented for the development and deployment of a robotic platform characterizing salt-impacted oil & gas reserve pits. After calibration, the relationship between the in situ robot chloride measurements and laboratory-based chloride measurements had a good linear relationship (R2-value = 0.861) and statistical significance (p-value = 0.003).

Distinct networks of periaqueductal gray columns in pain and threat processing.

Noxious events that can cause physical damage to the body are perceived as threats. In the brainstem, the periaqueductal gray (PAG) ensures survival by generating an appropriate response to these threats. Hence, the experience of pain is coupled with threat signaling and interfaces in the dl/l and vlPAG columns. In this study, we triangulate the functional circuits of the dl/l and vlPAG by using static and time-varying functional connectivity (FC) in multiple fMRI scans in healthy participants (n = 37, 21 female). The dl/l and vlPAG were activated during cue, heat, and rating periods when the cue signaled a high threat of experiencing heat pain and when the incoming intensity of heat pain was unknown. Responses were significantly lower after low threat cues. The two regions responded similarly to the cued conditions but showed prominent distinctions in the extent of FC with other brain regions. Thus, both static and time-varying FC showed significant differences in the functional circuits of dl/l and vlPAG in rest and task scans. The dl/lPAG consistently synchronized with the salience network and the thalamus, suggesting a role in threat detection, while the vlPAG exhibited more widespread synchronization and frequently connected with memory/language and sensory regions. Hence, these two PAG regions process heat pain when stronger pain is expected or when it is uncertain, and preferentially synchronize with distinct brain circuits in a reproducible manner. The dl/lPAG seems more directly involved in salience detection, while the vlPAG seems engaged in contextualizing threats.

Hoxb5 marks long-term haematopoietic stem cells and reveals a homogenous perivascular niche.

Haematopoietic stem cells (HSCs) are arguably the most extensively characterized tissue stem cells. Since the identification of HSCs by prospective isolation, complex multi-parameter flow cytometric isolation of phenotypic subsets has facilitated studies on many aspects of HSC biology, including self-renewal, differentiation, ageing, niche, and diversity. Here we demonstrate by unbiased multi-step screening, identification of a single gene, homeobox B5 (Hoxb5, also known as Hox-2.1), with expression in the bone marrow that is limited to long-term (LT)-HSCs in mice. Using a mouse single-colour tri-mCherry reporter driven by endogenous Hoxb5 regulation, we show that only the Hoxb5(+) HSCs exhibit long-term reconstitution capacity after transplantation in primary transplant recipients and, notably, in secondary recipients. Only 7-35% of various previously defined immunophenotypic HSCs are LT-HSCs. Finally, by in situ imaging of mouse bone marrow, we show that >94% of LT-HSCs (Hoxb5(+)) are directly attached to VE-cadherin(+) cells, implicating the perivascular space as a near-homogenous location of LT-HSCs.

Soluble CX3CL1 gene therapy improves cone survival and function in mouse models of retinitis pigmentosa.

Retinitis pigmentosa (RP) is a disease that initially presents as night blindness due to genetic deficits in the rod photoreceptors of the retina. Rods then die, causing dysfunction and death of cone photoreceptors, the cell type that mediates high acuity and color vision, ultimately leading to blindness. We investigated immune responses in mouse models of RP and found evidence of microglia activation throughout the period of cone degeneration. Using adeno-associated vectors (AAVs), delivery of genes encoding microglial regulatory signals led to the identification of AAV serotype 8 (AAV8) soluble CX3CL1 (sCX3CL1) as a promising therapy for degenerating cones. Subretinal injection of AAV8-sCX3CL1 significantly prolonged cone survival in three strains of RP mice. Rescue of cones was accompanied by improvements in visual function. AAV8-sCX3CL1 did not affect rod survival, microglia localization, or inflammatory cytokine levels in the retina. Furthermore, although RNA sequencing of microglia demonstrated marked transcriptional changes with AAV8-sCX3CL1, pharmacological depletion of up to ∼99% of microglia failed to abrogate the effect of AAV8-sCX3CL1 on cone survival. These findings indicate that AAV8-sCX3CL1 can rescue cones in multiple mouse models of RP via a pathway that does not require normal numbers of microglia. Gene therapy with sCX3CL1 is a promising mutation-independent approach to preserve vision in RP and potentially other forms of retinal degeneration.

AAV cis-regulatory sequences are correlated with ocular toxicity.

Adeno-associated viral vectors (AAVs) have become popular for gene therapy, given their many advantages, including their reduced inflammatory profile compared with that of other viruses. However, even in areas of immune privilege such as the eye, AAV vectors are capable of eliciting host-cell responses. To investigate the effects of such responses on several ocular cell types, we tested multiple AAV genome structures and capsid types using subretinal injections in mice. Assays of morphology, inflammation, and physiology were performed. Pathological effects on photoreceptors and the retinal pigment epithelium (RPE) were observed. Müller glia and microglia were activated, and the proinflammatory cytokines TNF-α and IL-1ß were up-regulated. There was a strong correlation between cis-regulatory sequences and toxicity. AAVs with any one of three broadly active promoters, or an RPE-specific promoter, were toxic, while AAVs with four different photoreceptor-specific promoters were not toxic at the highest doses tested. There was little correlation between toxicity and transgene, capsid type, preparation method, or cellular contaminants within a preparation. The toxic effect was dose-dependent, with the RPE being more sensitive than photoreceptors. Our results suggest that ocular AAV toxicity is associated with certain AAV cis-regulatory sequences and/or their activity and that retinal damage occurs due to responses by the RPE and/or microglia. By applying multiple, sensitive assays of toxicity, AAV vectors can be designed so that they can be used safely at high dose, potentially providing greater therapeutic efficacy.

Proteogenomic characterization of human colon and rectal cancer.

Extensive genomic characterization of human cancers presents the problem of inference from genomic abnormalities to cancer phenotypes. To address this problem, we analysed proteomes of colon and rectal tumours characterized previously by The Cancer Genome Atlas (TCGA) and perform integrated proteogenomic analyses. Somatic variants displayed reduced protein abundance compared to germline variants. Messenger RNA transcript abundance did not reliably predict protein abundance differences between tumours. Proteomics identified five proteomic subtypes in the TCGA cohort, two of which overlapped with the TCGA 'microsatellite instability/CpG island methylation phenotype' transcriptomic subtype, but had distinct mutation, methylation and protein expression patterns associated with different clinical outcomes. Although copy number alterations showed strong cis- and trans-effects on mRNA abundance, relatively few of these extend to the protein level. Thus, proteomics data enabled prioritization of candidate driver genes. The chromosome 20q amplicon was associated with the largest global changes at both mRNA and protein levels; proteomics data highlighted potential 20q candidates, including HNF4A (hepatocyte nuclear factor 4, alpha), TOMM34 (translocase of outer mitochondrial membrane 34) and SRC (SRC proto-oncogene, non-receptor tyrosine kinase). Integrated proteogenomic analysis provides functional context to interpret genomic abnormalities and affords a new paradigm for understanding cancer biology.

Expression of glypican 3 enriches hepatocellular carcinoma development-related genes and associates with carcinogenesis in cirrhotic livers.

Glypican-3 (GPC3) protein expression was determined by immunohistochemical analysis from 29 normal livers, 80 cirrhotic livers sample taken near hepatocellular carcinoma (HCC), and 87 cirrhotic livers without HCC. The levels for miR-657 and HCC-related gene mRNAs were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Also, a published microarray dataset was used for gene set enrichment analysis (GSEA) to investigate the relationship between GPC3- and HCC-related gene signatures. Kaplan-Meier analysis was used to evaluate the relationship between GPC3 and HCC recurrence. GPC3 protein expression was not detected in any of the 29 (0%) normal livers, but was detected in 32 of 87 (37%) cirrhotic livers without HCC, and 51 of 80 (64%) cirrhotic liver samples taken near HCC sites (P < 0.001). The GPC3-positive rate in cirrhotic livers of viral origin was 68% (27/40), which was significantly higher than for non-viral cirrhotic livers (11%, 5/47) (P < 0.001). Also, GPC3 expression positively correlated with mRNA expression of HCC-related genes in the qRT-PCR and GSEA evaluations. Furthermore, HCC recurrence in cirrhotic liver samples taken near HCC sites was significantly higher in the GPC3-positive group than the GPC3-negative group (Log-rank P = 0.02, HR = 3.26; 95% CI = 1.20-10.29). This study demonstrated that highly expression of GPC3 could enrich HCC-related genes' mRNA expression and positive associate with dysplasia in cirrhotic livers. Therefore, GPC3 may serve as a precancerous biomarker in cirrhotic livers.

Preclinical magnetic resonance imaging and systems biology in cancer research: current applications and challenges.

Biologically accurate mouse models of human cancer have become important tools for the study of human disease. The anatomical location of various target organs, such as brain, pancreas, and prostate, makes determination of disease status difficult. Imaging modalities, such as magnetic resonance imaging, can greatly enhance diagnosis, and longitudinal imaging of tumor progression is an important source of experimental data. Even in models where the tumors arise in areas that permit visual determination of tumorigenesis, longitudinal anatomical and functional imaging can enhance the scope of studies by facilitating the assessment of biological alterations, (such as changes in angiogenesis, metabolism, cellular invasion) as well as tissue perfusion and diffusion. One of the challenges in preclinical imaging is the development of infrastructural platforms required for integrating in vivo imaging and therapeutic response data with ex vivo pathological and molecular data using a more systems-based multiscale modeling approach. Further challenges exist in integrating these data for computational modeling to better understand the pathobiology of cancer and to better affect its cure. We review the current applications of preclinical imaging and discuss the implications of applying functional imaging to visualize cancer progression and treatment. Finally, we provide new data from an ongoing preclinical drug study demonstrating how multiscale modeling can lead to a more comprehensive understanding of cancer biology and therapy.

Discovery and diagnostic value of a novel oncofetal protein: glypican 3.

Glypican 3 is a membrane-bound heparan sulfate proteoglycan, which has recently been identified as a marker for liver cancer and germ cell malignancies. Individuals with loss-of-function mutations for the glypican 3 gene exhibit Simpson-Golabi-Behmel syndrome, a rare X-linked overgrowth disorder. Expression of glypican 3 mRNA and protein is normally silenced in most adult organs and may reappear during malignant transformation. In the past few years, immunohistochemical and molecular characteristics of glypican 3 in hepatocellular carcinoma have been elucidated. More recently, glypican 3 has been emerging as a new diagnostic marker for germ cell tumors and especially testicular and ovarian yolk sac tumors. However, in other tumors such as renal cell carcinomas, squamous cell carcinomas, and melanomas, studies disagree on the level of glypican 3 expression. Finally, there is the controversial notion of glypican 3 as a tumor suppressor gene. In this review article, we update current knowledge on glypican 3 expression in normal and neoplastic tissues, evaluate its utility as a tumor marker in clinical practice, and explore its role as a novel oncofetal protein with clinical implications. Our focus is on the diagnostic value of glypican 3 in germ cell tumors and other neoplasms in addition to hepatocellular carcinoma. In conclusion, glypican 3 has been proven to be a useful immunohistochemical marker in distinguishing yolk sac tumors, choriocarcinomas, and Wilms tumors from other malignancies histologically mimicking these primitive tumors. Clinically, we recommend that glypican 3 be used as part of a panel of markers in subtyping testicular germ cell tumors.

Comparing a Head-Mounted Smartphone Visual Field Analyzer to Standard Automated Perimetry in Glaucoma: A Prospective Study.

PRECIS: Wang et al compare an FDA-registered head-mounted smartphone device (PalmScan VF2000) with standard automated perimetry (SAP) in glaucoma patients and find that the head-mounted device may not fully recapitulate SAP testing. PURPOSE: This study prospectively compared visual field testing using the PalmScan VF2000 Visual Field Analyzer, a head-mounted smartphone device, with standard automated perimetry (SAP). METHODS: Patients with glaucoma undergoing Humphrey Field Analyzer SAP testing were asked to complete in-office PalmScan testing using a Samsung S5 smartphone in a virtual reality-style headset. Glaucoma severity was defined as SAP mean deviation (MD) >-6 dB for mild, between -6 and -12 dB for moderate, and <-12 dB for severe. Global parameters MD and pattern standard deviation (PSD) from PalmScan and SAP were compared using t-tests and Bland-Altman analyses. Bland-Altmann analyses of PalmScan and SAP MD were conducted for the superonasal, superotemporal, inferonasal, and inferotemporal visual field quadrants. The repeatability of PalmScan was assessed using Spearman's correlations and intraclass correlation coefficients (ICCs). RESULTS: Fifty-one patients (51 eyes) completed both SAP and PalmScan testing and met criteria for analysis. Compared to SAP, global MD and PSD measurements from PalmScan differed by an average of +0.62±0.26 dB (range: -3.25 to +4.60 dB) and -1.00±0.24 dB (range: -6.03 to +2.77 dB), respectively, while MD scores from individual visual field quadrants differed by as much as -6.58 to +11.43 dB. Agreement of PalmScan and SAP in classifying glaucoma severity was 86.3% across all eyes. PalmScan and SAP identified the same quadrant as having the worst visual field defect in 66.7% of eyes. CONCLUSIONS: Despite advantages in cost and accessibility, the PalmScan head-mounted perimetry device may not be able to fully recapitulate SAP testing.

A High-Avidity, Thermostable, and Low-Cost Synthetic Capture for Ultrasensitive Detection and Quantification of Viral Antigens and Aerosols.

Lateral flow assays (LFAs) are currently the most popular point-of-care diagnostics, rapidly transforming disease diagnosis from expensive doctor checkups and laboratory-based tests to potential on-the-shelf commodities. Yet, their sensitive element, a monoclonal antibody, is expensive to formulate, and their long-term storage depends on refrigeration technology that cannot be met in resource-limited areas. In this work, LCB1 affibodies (antibody mimetic miniproteins) were conjugated to bovine serum albumin (BSA) to afford a high-avidity synthetic capture (LCB1-BSA) capable of detecting the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and virus like particles (VLPs). Substituting the monoclonal antibody 2B04 for LCB1-BSA (stable up to 60 °C) significantly improved the thermal stability, shelf life, and affordability of plasmonic-fluor-based LFAs (p-LFAs). Furthermore, this substitution significantly improved the sensitivity of p-LFAs toward the spike protein and VLPs with precise quantitative ability over 2 and 3 orders of magnitude, respectively. LCB1-BSA sensors could detect VLPs at 100-fold lower concentrations, and this improvement, combined with their robust nature, enabled us to develop an aerosol sampling technology to detect aerosolized viral particles. Synthetic captures like LCB1-BSA can increase the ultrasensitivity, availability, sustainability, and long-term accuracy of LFAs while also decreasing their manufacturing costs.

Origin-specific epigenetic program correlates with vascular bed-specific differences in Rgs5 expression.

Cells from multiple origins contribute to vascular smooth muscle cell (VSMC) development. Phenotypic heterogeneity of VSMCs is associated with their point of developmental origin; however, the mechanisms driving such differences are unknown. We here examined the mechanisms controlling vascular bed-specific differences in Rgs5 expression during development. Rgs5 levels were similar across different regions of the vasculature in neonatal animals but were >15-fold higher in descending aortas compared with carotid arteries of adult mice. Thus, vessel bed-specific changes in regulation of Rgs5 expression occurred during vessel maturation. Examination of adult Rgs5-LacZ reporter mice revealed lower Rgs5 expression in VSMCs originating from the third (carotid artery) branchial arch compared with those originating in the fourth and sixth (aortic B segment, right subclavian, and ductus arteriosus) branchial arches. Indeed, a mosaic Rgs5 expression pattern, with discreet LacZ boundaries between VSMCs derived from different developmental origins, was observed. Furthermore, Rgs5-LacZ expression was correlated with the site of VSMC origin (splanchic mesoderm ≈ local mesenchyme > somites > proepicardium > mesothelium). Surprisingly, Rgs5 reporter activity in cultured carotid artery- and descending aorta-derived cells did not recapitulate the differences observed in vivo. Consistent with a developmental origin-specific epigenetic mechanism driving the observed expression differences in vivo, the Rgs5 promoter showed increased methylation on CpG dinucleotides in carotid arteries compared with that in descending aortas in adult but not in neonatal mice. In vitro methylation of the Rgs5 promoter confirmed that its activity is sensitive to transcriptional down-regulation by CpG methylation. These data suggest that an origin-dependent epigenetic program regulates vascular bed- and maturation state-dependent regulation of VSMC-specific gene transcription.

High-Yield, Case-Based, Interactive Workshop on Telehealth and Teleneurology With Pediatric Resident Physicians.

Introduction: Increasing prevalence of neurologic disorders with an aging global population and limited availability of neurologists may lead to worse patient outcomes. As a result of the COVID-19 pandemic, telehealth services surged, and despite easing public health measures, the demand has remained. Telehealth technology has the potential to close the physical gaps in expanding the reach of care. This academic half-day workshop sought to provide a learning opportunity in response to these concerns. Methods: The workshop consisted of small- and large-group case discussions among pediatric resident physicians (PGY 1-PGY 3) moderated by two child neurology faculty physicians over Zoom. Participants received a learner document with prereading articles and questions for each case. PowerPoint presentations with video demonstrations were used to introduce the cases and guide discussions. Results: Of the 25 attendees, 14 (56% response rate) answered a nonmandatory postsession survey. Eighty-six percent of the respondents were very or extremely satisfied with the content covered and were similarly satisfied with the effectiveness of content delivery. Seventy-nine percent of the respondents found the content helpful or very helpful in preparation for the board, and 93% anticipated applying the content covered occasionally or frequently in their clinical practice. Discussion: Small-group discussions with video demonstrations are helpful in increasing proficiency with telehealth technology and in examining board-relevant cases on pediatric patients. There is strong interest in subsequent telehealth half-day workshops that incorporate teaching through group discussions on relevant patient case scenarios.

Ocular Ischemic Syndrome in the Setting of Normal Carotid Duplex Ultrasound.

PURPOSE: To describe two cases of ocular ischemic syndrome (OIS) that were initially ruled out due to a negative carotid duplex ultrasound (DUS) but eventually confirmed by angiography studies. METHODS: Case series. RESULTS: Case 1: A 67-year-old female presented with symptoms suggestive of OIS, but carotid DUS was negative, and the patient was diagnosed with occlusive retinal vasculitis due to retinal non-perfusion and vascular leakage on fluorescein angiography (FA). Immunosuppressive therapy was initiated but her symptoms did not improve. Computerized tomography angiography (CTA) was significant for severe osteal stenosis of the aortic arch vessels. Left common carotid angioplasty and stenting resulted in complete resolution of the symptoms and vascular leakage of the left eye. Case 2: A 41-year-old male with cryoglobulinemia-associated vasculitis complained of symptoms consistent with OIS, which was initially ruled out through a negative carotid DUS. FA revealed delayed arterial filling with poor retinal perfusion. Magnetic resonance angiography (MRA) revealed ophthalmic artery stenosis which was attributed to the underlying systemic vasculitis. CONCLUSION: CTA or MRA should be performed to rule out OIS if DUS is negative in the setting of high clinical suspicion. Carotid ostial and ophthalmic artery stenoses are rare but possible causes of OIS.

The relationship between smartphone addiction and sleep among medical students: A systematic review and meta-analysis.

OBJECTIVES: This systematic review aimed to evaluate the association between smartphone addiction and sleep in medical students. The secondary outcomes included the prevalence of smartphone addiction, duration and purpose of its use, prevalence of poor sleep, duration and quality of sleep. METHODS: The authors searched PubMed, Cochrane Library, Embase, PsycINFO and CINAHL databases, from inception of each database to October 2022. Quantitative studies in the English language on smartphone addiction and sleep in students studying Western Medicine were included. The Rayyan application was used for title-abstract screening, and Joanna Briggs Institute (JBI) critical appraisal checklist to assess the risk of bias. Heterogeneity tests and meta-synthesis of data were performed using the meta-package in R software. Data on the activities used on the smartphone was synthesized qualitatively. RESULTS: A total of 298 abstracts were initially assessed for inclusion eligibility: 16 of them were eventually appraised, covering 9466 medical students comprising 3781 (39.9%) males and 5161 (54.5%) females. Meta-correlation between the Smartphone Addiction Scale Short Version (SAS-SV) and Pittsburgh Sleep Quality Index (PSQI) was 0.30 (95%CI = 0.24-0.36), and 0.27 (95% CI = 0.18-0.36) for SAS-SV and sleep duration. The meta-analytic estimation of smartphone addiction prevalence was 39% (95%CI = 0.30-0.50), and score using SAS-SV was 31.11 (95%CI = 29.50-32.72). The mean duration of smartphone daily used was 4.90 hours (95%CI = 3.72-6.08). The meta-analytic estimation on prevalence of poor sleep was 57% (95%CI = 0.48-0.66), and the meta-mean of PSQI and duration of sleep was 5.95 (95%CI = 4.90-7.00) and 5.62h (95%CI = 4.87-6.36) respectively. Medical students used their smartphones mostly for text messaging, followed by photo-sharing or social networking. Its usage for medical education remains unclear. CONCLUSION: The prevalence of poor sleep and smartphone addiction in medical students was 57% and 39% respectively, with a correlation index of 0.30. Medical students commonly used the smartphone for text-messaging, photo-sharing or social networking, averaging 4.9 hours daily.

High temporal frequency light response in mouse retina is mediated by ON and OFF bipolar cells and requires FAT3 signaling.

Vision is initiated by the reception of light by photoreceptors and subsequent processing via parallel retinal circuits. Proper circuit organization depends on the multi-functional tissue polarity protein FAT3, which is required for amacrine cell connectivity and retinal lamination. Here we investigated the retinal function of Fat3 mutant mice and found decreases in physiological and perceptual responses to high frequency flashes. These defects did not correlate with abnormal amacrine cell wiring, pointing instead to a role in bipolar cell subtypes that also express FAT3. Indeed, similar deficits were observed in mice lacking the bipolar cell glutamate receptors GRIK1 (OFF-bipolar cells) and GRM6 (ON-bipolar cells). Mechanistically, FAT3 binds to the synaptic protein PTPσ and is required to localize GRIK1 to OFF-cone bipolar cell synapses with cone photoreceptors. How FAT3 impacts ON-cone bipolar cell function at high temporal frequency remains to be uncovered. These findings expand the repertoire of FAT3's functions and reveal the importance of both ON- and OFF-bipolar cells for high frequency light response.