Retinal vascular reactivity in carriers of X-linked inherited retinal disease - a study using optical coherence tomography angiography.

Purpose: Female carriers of X-linked inherited retinal diseases (IRDs) can show highly variable phenotypes and disease progression. Vascular reactivity, a potential disease biomarker, has not been investigated in female IRD carriers. In this study, functional optical coherence tomography angiography (OCT-A) was used to dynamically assess the retinal microvasculature of X-linked IRD carriers. Methods: Genetically confirmed female carriers of IRDs (choroideremia or X-linked retinitis pigmentosa), and healthy women were recruited. Macular angiograms (3x3mm, Zeiss Plex Elite 9000) were obtained in 36 eyes of 15 X-linked IRD female carriers and 21 age-matched control women. Two tests were applied to test vascular reactivity: (i) mild hypoxia and (ii) handgrip test, to induce a vasodilatory or vasoconstrictive response, respectively. Changes to vessel density (VD) and vessel length density (VLD) were independently evaluated during each of the tests for both the superficial and deep capillary plexuses. Results: In the control group, the superficial and deep VD decreased during the handgrip test (p<0.001 and p=0.037, respectively). Mean superficial VLD also decreased during the handgrip test (p=0.025), while the deep plexus did not change significantly (p=0.108). During hypoxia, VD and VLD increased in the deep plexus (p=0.027 and p=0.052, respectively) but not in the superficial plexus. In carriers, the physiologic vascular responses seen in controls were not observed in either plexus during either test, with no difference in VD or VLD noted (all p>0.05). Conclusions: Functional OCT-A is a useful tool to assess dynamic retinal microvascular changes. Subclinical impairment of the physiological vascular responses seen in carriers of X-linked IRDs may serve as a valuable clinical biomarker.

Causes of mortality in military working dog from traumatic injuries.

Introduction: This study aimed to identify the pathophysiologic causes of death following traumatic injuries in military working dogs (MWDs) and determine the risk factors associated with mortality in MWD following traumatic injuries. The results of this study will allow for better targeting of interventions to ameliorate these pathophysiologic causes of death and inform research priorities directed at the pathophysiology that leads to the death of MWDs. Methods: The final dataset for this study was compiled by using two previously established datasets. Based on review of available data and supplemental records (when available), MWDs in which a definitive cause of death could be determined were included in the study population. These MWDs were assigned a cause of death based on categories previously identified in studies evaluating service member casualties. A group of MWDs who survived their traumatic injury and had similar mechanisms of injury and types of injury to the deceased MWDs were included to allow for comparison and establishment of risk factors associated with MWD death. Variables collected included breed, age, sex, mechanism of injury, survival/non-survival, type of trauma, mechanism of injury, pathophysiology that led to death and pre-hospital care provided. Statistical analysis included Fishers exact test for categorical variables and univariable and multivariable logistic regression to identify factors associated with the MWD death. Results: A total of 84 MWDs (33 non-survivors and 51 survivors) were included in this study. Of the 33 MWDs that died, 27 (81.8%) were noted to be dead on arrival. The pathophysiologic causes of death were found to be hemorrhage (45.5% [n = 15]), head trauma (21.2% [n = 7]), catastrophic tissue destruction (15.2% [n = 5]), pneumothorax (9.1% [n = 3]) and one (3% [n = 1]) of each of the following: septic shock, asphyxiation and burns. Military working dogs that did not receive non-DVM care were 3.55 times more likely to die than those that did receive non-DVM care (95% CI 1.03-12.27). The majority of MWDs died of their injuries before reaching veterinary care. Discussion: To increase the survival of MWDs on the battlefield, further research should focus on developing new interventions and techniques to mitigate the effects of the pathophysiology noted to cause MWD death. Furthermore, given that care by a non-DVM was found to be associated with survival, the implementation of pre-hospital care and early resuscitation techniques should be a continued priority for those treating MWDs at both the point of injury and in the prehospital setting.

Understanding ß-strand mediated protein-protein interactions: tuning binding behaviour of intrinsically disordered sequences by backbone modification.

A significant challenge in chemical biology is to understand and modulate protein-protein interactions (PPIs). Given that many PPIs involve a folded protein domain and a peptide sequence that is intrinsically disordered in isolation, peptides represent powerful tools to understand PPIs. Using the interaction between small ubiquitin-like modifier (SUMO) and SUMO-interacting motifs (SIMs), here we show that N-methylation of the peptide backbone can effectively restrict accessible peptide conformations, predisposing them for protein recognition. Backbone N-methylation in appropriate locations results in faster target binding, and thus higher affinity, as shown by relaxation-based NMR experiments and computational analysis. We show that such higher affinities occur as a consequence of an increase in the energy of the unbound state, and a reduction in the entropic contribution to the binding and activation energies. Thus, backbone N-methylation may represent a useful modification within the peptidomimetic toolbox to probe ß-strand mediated interactions.

Deep learning models for interpretation of point of care ultrasound in military working dogs.

Introduction: Military working dogs (MWDs) are essential for military operations in a wide range of missions. With this pivotal role, MWDs can become casualties requiring specialized veterinary care that may not always be available far forward on the battlefield. Some injuries such as pneumothorax, hemothorax, or abdominal hemorrhage can be diagnosed using point of care ultrasound (POCUS) such as the Global FAST® exam. This presents a unique opportunity for artificial intelligence (AI) to aid in the interpretation of ultrasound images. In this article, deep learning classification neural networks were developed for POCUS assessment in MWDs. Methods: Images were collected in five MWDs under general anesthesia or deep sedation for all scan points in the Global FAST® exam. For representative injuries, a cadaver model was used from which positive and negative injury images were captured. A total of 327 ultrasound clips were captured and split across scan points for training three different AI network architectures: MobileNetV2, DarkNet-19, and ShrapML. Gradient class activation mapping (GradCAM) overlays were generated for representative images to better explain AI predictions. Results: Performance of AI models reached over 82% accuracy for all scan points. The model with the highest performance was trained with the MobileNetV2 network for the cystocolic scan point achieving 99.8% accuracy. Across all trained networks the diaphragmatic hepatorenal scan point had the best overall performance. However, GradCAM overlays showed that the models with highest accuracy, like MobileNetV2, were not always identifying relevant features. Conversely, the GradCAM heatmaps for ShrapML show general agreement with regions most indicative of fluid accumulation. Discussion: Overall, the AI models developed can automate POCUS predictions in MWDs. Preliminarily, ShrapML had the strongest performance and prediction rate paired with accurately tracking fluid accumulation sites, making it the most suitable option for eventual real-time deployment with ultrasound systems. Further integration of this technology with imaging technologies will expand use of POCUS-based triage of MWDs.

The cryoEM structure of the Hendra henipavirus nucleoprotein reveals insights into paramyxoviral nucleocapsid architectures.

We report the first cryoEM structure of the Hendra henipavirus nucleoprotein in complex with RNA, at 3.5 Å resolution, derived from single particle analysis of a double homotetradecameric RNA-bound N protein ring assembly exhibiting D14 symmetry. The structure of the HeV N protein adopts the common bi-lobed paramyxoviral N protein fold; the N-terminal and C-terminal globular domains are bisected by an RNA binding cleft containing six RNA nucleotides and are flanked by the N-terminal and C-terminal arms, respectively. In common with other paramyxoviral nucleocapsids, the lateral interface between adjacent Ni and Ni+1 protomers involves electrostatic and hydrophobic interactions mediated primarily through the N-terminal arm and globular domains with minor contribution from the C-terminal arm. However, the HeV N multimeric assembly uniquely identifies an additional protomer-protomer contact between the Ni+1 N-terminus and Ni-1 C-terminal arm linker. The model presented here broadens the understanding of RNA-bound paramyxoviral nucleocapsid architectures and provides a platform for further insight into the molecular biology of HeV, as well as the development of antiviral interventions.

Retinal Characteristics of Female Choroideremia Carriers: Multimodal Imaging, Microperimetry, and Genetics.

PURPOSE: To describe visual function and retinal features of female carriers of choroideremia (CHM), using multimodal imaging and microperimetry. DESIGN: Cross-sectional cohort study. PARTICIPANTS AND CONTROLS: Choroideremia carriers seen in Australia (Melbourne or Perth) or the United Kingdom (Oxford or Cambridge) between 2012 and 2023. Healthy age-matched controls seen in Melbourne, Australia, between 2022 and 2023. METHODS: Participants had visual acuity, fundus-tracked microperimetry, OCT, and fundus autofluorescence imaging performed. Choroideremia carriers were either genetically or clinically confirmed (i.e., obligate carriers). Choroideremia carriers were grouped according to their retinal phenotype and compared with healthy controls. Statistical analyses were performed on StataBE (v18.0). MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), average retinal sensitivity, volume of macular hill of vision (HoV), inner retinal thickness, and photoreceptor complex (PRC) thickness. RESULTS: Eighty-six eyes of 43 CHM carriers and 60 eyes of 30 healthy controls were examined using multimodal imaging and microperimetry. Median age was 54 and 48.5 years for CHM carriers and controls, respectively (P = 0.18). Most CHM carriers (86%) were genetically confirmed. Choroideremia carriers and controls had strong intereye correlation between eyes for BCVA and average retinal sensitivity (P < 0.001). Low-luminance visual acuity and macular HoV tests were sensitive tests to detect changes in CHM carriers with mild phenotypes (i.e., fine and coarse). Choroideremia carriers with geographic or male-pattern phenotypes had reduced BCVA, LLVA, retinal sensitivity, and retinal thinning, compared with healthy controls. Retinal thickening of the inner retina was observed in the central 1°, despite generalized thinning of the PRC in the central 7°, indicating retinal remodeling in CHM carriers, compared with controls. There were no genotype-phenotype correlations observed. CONCLUSIONS: Female carriers of CHM with severe retinal phenotypes (i.e., geographic or male pattern) have significantly decreased visual function and retinal structural changes when compared with age-matched controls and those carriers with milder phenotypes. Low-luminance visual acuity and volumetric measures of the macular HoV were found to be the most sensitive functional tests to detect milder retinal disease (fine and coarse phenotypes) in CHM carriers. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparison of shelf-stable and conventional resuscitation products in a canine model of hemorrhagic shock.

BACKGROUND: Treatment of severe hemorrhagic shock typically involves hemostatic resuscitation with blood products. However, logistical constraints often hamper the wide distribution of commonly used blood products like whole blood. Shelf-stable blood products and blood substitutes are poised to be able to effectively resuscitate individuals in hemorrhagic shock when more conventional blood products are not readily available. METHODS: Purpose-bred adult dogs (n = 6) were anesthetized, instrumented, and subjected to hemorrhagic shock (mean arterial pressure <50 mm Hg or 40% blood volume loss). Then each dog was resuscitated with one of five resuscitation products: (1) lactated ringers solution and hetastarch (LRS/Heta), (2) canine chilled whole blood (CWB), (3) fresh frozen plasma (FFP) and packed red blood cells (pRBC), (4) canine freeze-dried plasma (FDP) and hemoglobin-based oxygen carrier (HBOC), or (5) HBOC/FDP and canine lyophilized platelets (LyoPLT). Each dog was allowed to recover after the hemorrhage resuscitation event and was then subjected to another hemorrhage event and resuscitated with a different product until each dog was resuscitated with each product. RESULTS: At the time when animals were determined to be out of shock as defined by a shock index <1, mean arterial pressure (mmHg) values (mean ± standard error) were higher for FFP/pRBC (n = 5, 83.7 ± 4.5) and FDP/HBOC+LyoPLT (n = 4, 87.8 ± 2.1) as compared with WB (n = 4, 66.0 ± 13.1). A transient increase in creatinine was seen in dogs resuscitated with HBOC and FDP. Albumin and base excess increased in dogs resuscitated with HBOC and FDP products compared with LRS/heta and CWB ( p < 0.01). CONCLUSION: Combinations of shelf-stable blood products compared favorably to canine CWB for resolution of shock. Further research is needed to ascertain the reliability and efficacy of these shelf-stable combinations of products in other models of hemorrhage that include a component of tissue damage as well as naturally occurring trauma.

Retinal Dystrophies Associated With Peripherin-2: Genetic Spectrum and Novel Clinical Observations in 241 Patients.

Purpose: To describe the clinical, electrophysiological and genetic spectrum of inherited retinal diseases associated with variants in the PRPH2 gene. Methods: A total of 241 patients from 168 families across 15 sites in 9 countries with pathogenic or likely pathogenic variants in PRPH2 were included. Records were reviewed for age at symptom onset, visual acuity, full-field ERG, fundus colour photography, fundus autofluorescence (FAF), and SD-OCT. Images were graded into six phenotypes. Statistical analyses were performed to determine genotype-phenotype correlations. Results: The median age at symptom onset was 40 years (range, 4-78 years). FAF phenotypes included normal (5%), butterfly pattern dystrophy, or vitelliform macular dystrophy (11%), central areolar choroidal dystrophy (28%), pseudo-Stargardt pattern dystrophy (41%), and retinitis pigmentosa (25%). Symptom onset was earlier in retinitis pigmentosa as compared with pseudo-Stargardt pattern dystrophy (34 vs 44 years; P = 0.004). The median visual acuity was 0.18 logMAR (interquartile range, 0-0.54 logMAR) and 0.18 logMAR (interquartile range 0-0.42 logMAR) in the right and left eyes, respectively. ERG showed a significantly reduced amplitude across all components (P < 0.001) and a peak time delay in the light-adapted 30-Hz flicker and single-flash b-wave (P < 0.001). Twenty-two variants were novel. The central areolar choroidal dystrophy phenotype was associated with 13 missense variants. The remaining variants showed marked phenotypic variability. Conclusions: We described six distinct FAF phenotypes associated with variants in the PRPH2 gene. One FAF phenotype may have multiple ERG phenotypes, demonstrating a discordance between structure and function. Given the vast spectrum of PRPH2 disease our findings are useful for future clinical trials.

Structural basis for the broad antigenicity of the computationally optimized influenza hemagglutinin X6.

Influenza causes significant morbidity and mortality. As an alternative approach to current seasonal vaccines, the computationally optimized broadly reactive antigen (COBRA) platform has been previously applied to hemagglutinin (HA). This approach integrates wild-type HA sequences into a single immunogen to expand the breadth of accessible antibody epitopes. Adding to previous studies of H1, H3, and H5 COBRA HAs, we define the structural features of another H1 subtype COBRA, X6, that incorporates HA sequences from before and after the 2009 H1N1 influenza pandemic. We determined structures of this antigen alone and in complex with COBRA-specific as well as broadly reactive and functional antibodies, analyzing its antigenicity. We found that X6 possesses features representing both historic and recent H1 HA strains, enabling binding to both head- and stem-reactive antibodies. Overall, these data confirm the integrity of broadly reactive antibody epitopes of X6 and contribute to design efforts for a next-generation vaccine.

Gene and cell therapy for age-related macular degeneration: A review.

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss among the elderly in Western communities, with an estimated global prevalence of 10 - 20% in people older than 65 years. AMD leads to central vision loss due to degeneration of the photoreceptors, retinal pigment epithelium and the choriocapillaris. Beckman's classification for AMD, based upon color fundus photographs, divides the disease into early, intermediate, and late forms. The late, vision-threatening stage includes both neovascular AMD and geographic atrophy. Despite its high prevalence and impact on patients' quality of life, treatment options for AMD are limited. While neovascular AMD can be medically managed with anti-VEGF intravitreal injections, until very recently there has been no approved treatment options for atrophic AMD; however, in February 2023 the first treatment for geographic atrophy - pegcetacoplan - was approved by the US FDA. We describe the current landscape of potential gene and cell therapeutic strategies for late-stage AMD, with an emphasis on the therapeutic options that might become available in the next few years.

Utilization of RNA sequencing to investigate olfactory dysfunction in chronic rhinosinusitis without nasal polyps: A pilot study.

Objectives: Prior research on olfactory dysfunction in chronic rhinosinusitis (CRS) has focused on patients with polyps and suggests that direct inflammation of the olfactory cleft mucosa plays a contributory role. The purpose of this study was to evaluate gene expression in superior turbinate mucosal specimens, comparing normosmic and dysosmic CRS patients without polyps (CRSsNP). Methods: Tissue samples were obtained from the superior turbinates of patients with CRSsNP at the time of endoscopic sinus surgery. Samples subsequently underwent RNA sequencing and functional analysis to investigate biological pathways associated with differentially expressed genes between dysosmic (n = 7) and normosmic (n = 4) patients. Results: Differential gene expression analysis comparing dysosmic and normosmic CRSsNP patients showed upregulation of 563 genes and downregulation of 327 genes. Using stringent criteria for multiple comparisons, one upregulated gene (Immediate Early Response 3 [IER3]) had an false discovery rate (FDR) correction adjusted P value considered statistically significant (P < 0.001, fold change 2.69). Reactome functional analysis revealed eight biological pathways significantly different between dysosmic and normosmic patients (P < 0.05, FDR correction) including IL-4 and IL-13 signaling, IL-10 signaling, and rhodopsin-like receptors. Conclusions: RNA sequencing of the superior turbinates in patients with CRSsNP can provide valuable information regarding biological pathways and genes involved in olfactory dysfunction. This study supports literature suggesting that Type 2 inflammation may play a role in olfactory dysfunction in at least some patients with CRSsNP. This study also prompts questions regarding the role of IL-10, rhodopsin-like receptors, and IER3 in the pathogenesis of olfactory dysfunction.

Comparison of trigeminal lateralization with differing stimulants.

Trigeminal-specific stimulants have been shown to activate different receptors preferentially and this likely accounts for variation in sensory perception. It is unclear whether trigeminal sensitivity is similar across different transient receptor potential (TRP) receptors or if dysfunction of different receptors results in differing patient symptoms. Therefore, a prospective cohort study was conducted, consisting of trigeminal lateralization testing with three different stimulants (eucalyptol, isothiocyanate, acetic acid), olfaction testing with Sniffin' Sticks, and measurement of various patient-reported outcome measures (PROMs). A total of 50 participants were enrolled across the olfactory spectrum. Mean TDI score was 27.1 ± 8.3 (range 7.0-39.5) with 38% normosmic and 62% dysosmic. Mean trigeminal lateralization scores out of 20 in the overall cohort were 16.18 (2.78) for eucalyptol, 14.94 (3.49) for mustard oil, and 15.28 (3.68) for vinegar. Eucalyptol showed a significant correlation with threshold scores of Sniffin' Sticks. A significant correlation was found between acetic acid and various PROMs. None of the lateralization scores of the trigeminal stimulants correlated to each other significantly and there was no correlation to age. The lack of correlation suggests that the measured sensitivity of one type of TRP receptor may not translate to similar sensitivity of the other receptors. Additional investigations with TRPV1 and TRPA1 agonists are needed to corroborate our findings.

Structural and functional characterization of FabG4 from Mycolicibacterium smegmatis.

The rise in antimicrobial resistance is a global health crisis and necessitates the development of novel strategies to treat infections. For example, in 2022 tuberculosis (TB) was the second leading infectious killer after COVID-19, with multi-drug-resistant strains of TB having an ∼40% fatality rate. Targeting essential biosynthetic pathways in pathogens has proven to be successful for the development of novel antimicrobial treatments. Fatty-acid synthesis (FAS) in bacteria proceeds via the type II pathway, which is substantially different from the type I pathway utilized in animals. This makes bacterial fatty-acid biosynthesis (Fab) enzymes appealing as drug targets. FabG is an essential FASII enzyme, and some bacteria, such as Mycobacterium tuberculosis, the causative agent of TB, harbor multiple homologs. FabG4 is a conserved, high-molecular-weight FabG (HMwFabG) that was first identified in M. tuberculosis and is distinct from the canonical low-molecular-weight FabG. Here, structural and functional analyses of Mycolicibacterium smegmatis FabG4, the third HMwFabG studied to date, are reported. Crystal structures of NAD+ and apo MsFabG4, along with kinetic analyses, show that MsFabG4 preferentially binds and uses NADH when reducing CoA substrates. As M. smegmatis is often used as a model organism for M. tuberculosis, these studies may aid the development of drugs to treat TB and add to the growing body of research that distinguish HMwFabGs from the archetypal low-molecular-weight FabG.

Patient experiences and perceived value of genetic testing in inherited retinal diseases: a cross-sectional survey.

This study evaluated patient experiences with genetic testing for inherited retinal diseases (IRDs) and the association between underlying knowledge, testing outcomes, and the perceived value of the results. An online survey was distributed to adults with IRDs and parents/guardians of dependents with IRDs who had had genetic testing. Data included details of genetic testing, pre- and post- test perceptions, Decision Regret Scale, perceived value of results, and knowledge of gene therapy. Of 135 responses (85% from adults with IRDs), genetic testing was primarily conducted at no charge through public hospitals (49%) or in a research setting (30%). Key motivations for genetic testing were to confirm IRD diagnosis and to contribute towards research. Those who had received a genetic diagnosis (odds ratio: 6.71; p < 0.001) and those self-reported to have good knowledge of gene therapy (odds ratio: 2.69; p = 0.018) were more likely to have gained confidence in managing their clinical care. For over 80% of respondents, knowing the causative gene empowered them to learn more about their IRD and explore opportunities regarding clinical trials. Key genetic counselling information needs include resources for family communications, structured information provision, and ongoing genetic support, particularly in the context of emerging ocular therapies, to enhance consistency in information uptake.

Crystal structure and biophysical characterization of IspD from Burkholderia thailandensis and Mycobacterium paratuberculosis.

The methylerythritol phosphate (MEP) pathway is a metabolic pathway that produces the isoprenoids isopentyl pyrophosphate and dimethylallyl pyrophosphate. Notably, the MEP pathway is present in bacteria and not in mammals, which makes the enzymes of the MEP pathway attractive targets for discovering new anti-infective agents due to the reduced chances of off-target interactions leading to side effects. There are seven enzymes in the MEP pathway, the third of which is IspD. Two crystal structures of Burkholderia thailandensis IspD (BtIspD) were determined: an apo structure and that of a complex with cytidine triphosphate (CTP). Comparison of the CTP-bound BtIspD structure with the apo structure revealed that CTP binding stabilizes the loop composed of residues 13-19. The apo structure of Mycobacterium paratuberculosis IspD (MpIspD) is also reported. The melting temperatures of MpIspD and BtIspD were evaluated by circular dichroism. The moderate Tm values suggest that a thermal shift assay may be feasible for future inhibitor screening. Finally, the binding affinity of CTP for BtIspD was evaluated by isothermal titration calorimetry. These structural and biophysical data will aid in the discovery of IspD inhibitors.

Genetic analysis and molecular basis of G6PD deficiency among malaria patients in Thailand: implications for safe use of 8-aminoquinolines.

BACKGROUND: It was hypothesized that glucose-6-phosphate dehydrogenase (G6PD) deficiency confers a protective effect against malaria infection, however, safety concerns have been raised regarding haemolytic toxicity caused by radical cure with 8-aminoquinolines in G6PD-deficient individuals. Malaria elimination and control are also complicated by the high prevalence of G6PD deficiency in malaria-endemic areas. Hence, accurate identification of G6PD deficiency is required to identify those who are eligible for malaria treatment using 8-aminoquinolines. METHODS: The prevalence of G6PD deficiency among 408 Thai participants diagnosed with malaria by microscopy (71), and malaria-negative controls (337), was assessed using a phenotypic test based on water-soluble tetrazolium salts. High-resolution melting (HRM) curve analysis was developed from a previous study to enable the detection of 15 common missense, synonymous and intronic G6PD mutations in Asian populations. The identified mutations were subjected to biochemical and structural characterisation to understand the molecular mechanisms underlying enzyme deficiency. RESULTS: Based on phenotypic testing, the prevalence of G6PD deficiency (< 30% activity) was 6.13% (25/408) and intermediate deficiency (30-70% activity) was found in 15.20% (62/408) of participants. Several G6PD genotypes with newly discovered double missense variants were identified by HRM assays, including G6PD Gaohe + Viangchan, G6PD Valladolid + Viangchan and G6PD Canton + Viangchan. A significantly high frequency of synonymous (c.1311C>T) and intronic (c.1365-13T>C and c.486-34delT) mutations was detected with intermediate to normal enzyme activity. The double missense mutations were less catalytically active than their corresponding single missense mutations, resulting in severe enzyme deficiency. While the mutations had a minor effect on binding affinity, structural instability was a key contributor to the enzyme deficiency observed in G6PD-deficient individuals. CONCLUSIONS: With varying degrees of enzyme deficiency, G6PD genotyping can be used as a complement to phenotypic screening to identify those who are eligible for 8-aminoquinolines. The information gained from this study could be useful for management and treatment of malaria, as well as for the prevention of unanticipated reactions to certain medications and foods in the studied population.

The use of a kaolin-based hemostatic dressing to attenuate bleeding in dogs: A series of 4 cases.

OBJECTIVE: To describe the use of a synthetic hemostatic dressing, QuikClot Combat Gauze (QCG), in dogs with bleeding wounds. CASE SERIES SUMMARY: Two dogs presented with bleeding traumatic wounds, and QCG was used to achieve hemostasis during stabilization of these dogs. In the other 2 dogs, QCG was used to help attenuate bleeding associated with a surgical procedure. NEW OR UNIQUE INFORMATION PROVIDED: While hemostatic dressings have been widely studied and used in human medicine, there is minimal information on the use and efficacy of these hemostatic dressings in veterinary medicine. This case series describes the use of QCG in dogs with hemorrhaging wounds. QCG could be a valuable resource in veterinary emergency and critical care settings.

Optical coherence tomography in children with inherited retinal disease.

Recent advances have led to therapeutic options becoming available for people with inherited retinal disease. In particular, gene therapy has been shown to hold great promise for slowing vision loss from inherited retinal disease. Recent studies suggest that gene therapy is likely to be most effective when implemented early in the disease process, making consideration of paediatric populations important. It is therefore necessary to have a comprehensive understanding of retinal imaging in children with inherited retinal diseases, in order to monitor disease progression and to determine which early retinal biomarkers may be used as outcome measures in future clinical trials. In addition, as many optometrists will review children with an inherited retinal disease, an understanding of the expected imaging outcomes can improve clinical care. This review focuses on the most common imaging modality used in research assessment of paediatric inherited retinal diseases: optical coherence tomography. Optical coherence tomography findings can be used in both the clinical and research setting. In particular, the review discusses current knowledge of optical coherence tomography findings in eight paediatric inherited retinal diseases - Stargardt disease, Bests disease, Leber's congenital amaurosis, choroideremia, RPGR related retinitis pigmentosa, Usher syndrome, X-linked retinoschisis and, Batten disease.

Chimeric antigens displaying GPR65 extracellular loops on a soluble scaffold enabled the discovery of antibodies, which recognized native receptor.

GPR65 is a proton-sensing G-protein coupled receptor associated with multiple immune-mediated inflammatory diseases, whose function is relatively poorly understood. With few reagents commercially available to probe the biology of receptor, generation of an anti-GPR65 monoclonal antibody was desired. Using soluble chimeric scaffolds, such as ApoE3, displaying the extracellular loops of GPR65, together with established phage display technology, native GPR65 loop-specific antibodies were identified. Phage-derived loop-binding antibodies recognized the wild-type native receptor to which they had not previously been exposed, generating confidence in the use of chimeric soluble proteins to act as efficient surrogates for membrane protein extracellular loop antigens. This technique provides promise for the rational design of chimeric antigens in facilitating the discovery of specific antibodies to GPCRs.

This technique offers a viable approach for antibody discovery to difficult GPCRs.Structurally relevant, soluble chimeric scaffold proteins of GPR65 were generated.Chimeric antigens were used to identify GPR65-specific antibodies by phage display.

In vitro evaluation of hyperosmotic canine plasma suitable for infusion.

OBJECTIVE: To determine the characteristics of canine freeze-dried plasma (cFDP) as it is serially diluted with sterile water. DESIGN: In vitro experimental study. SETTING: Government blood and coagulation research laboratory. ANIMALS: cFDP from a commercial manufacturer. INTERVENTIONS: Ten units of cFDP were reconstituted to 100%, 90%, 80%, 70%, 60%, 50%, and 40% of the recommended volume with sterile water. The resultant solutions were analyzed for coagulation factor activity (factors II, V, VII, VIII, IX, X, and XII as well as antithrombin), fibrinogen concentration, prothrombin time, activated partial thromboplastin time, viscosity, osmolality, and kaolin-activated thromboelastography. MEASUREMENTS AND MAIN RESULTS: Viscosity, osmolality, and turbidity properties of plasma were increased in a reconstitution volume-dependent manner, with the 40% suggested volume generating approximately 2-fold increases in each. Similarly, factor activity levels and fibrinogen concentration increased by approximately 2-fold over this range in a concentration-dependent manner. Prothrombin time declined from 11.4 seconds at 100% volume to 10.9 seconds at 70% before increasing to 11.9 seconds at 40%. Activated partial thromboplastin time increased exponentially from 21.8 seconds at 100% rehydration to 100.0 seconds at 40%. R-time on TEG increased from 3.1 to 13.9 minutes at 50% rehydration, while alpha angle declined from 61.3° to 24.7° over the same range, and the maximum amplitude initially increased from 13.2 mm at 100% water to 18.6 mm at 70% water before dropping back down to 14.6 mm at 50% water. No clotting was observed with 40% rehydration. CONCLUSIONS: The creation of hyperosmotic plasma from cFDP appears feasible with preservation of concentrated coagulation factors, although there are some unexplained effects that happen to coagulation functions at the highest concentrations tested using only 40%-50% of recommended rehydration volume. Further studies are needed to evaluate the hyperosmotic product in vivo.