In vitro activity of omadacycline against clinical isolates of Nocardia

Nocardiosis typically requires a prolonged treatment duration of ≥6 months and initial combination therapy with 2-3 antibiotics. First-line regimens for nocardiosis are associated with considerable toxicity; therefore, alternative therapies are needed. Omadacycline is an aminomethylcycline with broad antimicrobial activity whose in vitro activity against Nocardia species has not been formally assessed. The in vitro potency of omadacycline was evaluated against 300 Nocardia clinical isolates by broth microdilution. The most common Nocardia species tested were N. cyriacigeorgica (21%), N. nova (20%), and N. farcinica (12%). The most common specimens were respiratory (178 isolates, 59%) and wound (57 isolates, 19%). Omadacycline minimum inhibitory concentrations (MICs) across all Nocardia species ranged from 0.06 µg/mL to 8 µg/mL, with an MIC50 of 2 µg/mL and MIC90 of 4 µg/mL. The lowest MICs were found among N. paucivorans (MIC50 = 0.25 µg/mL, MIC90 = 0.25 µg/mL), N. asiatica (MIC50 = 0.25 µg/mL, MIC90 = 1 µg/mL), N. abscessus complex (MIC50 = 0.5 µg/mL, MIC90 = 1 µg/mL), N. beijingensis (MIC50 = 0.5 µg/mL, MIC90 = 2 µg/mL), and N. otitidiscaviarum (MIC50 = 1 µg/mL, MIC90 = 2 µg/mL). The highest MICs were found among N. farcinica (MIC50 = 4 µg/mL, MIC90 = 8 µg/mL). In vitro potency differed by species among Nocardia clinical isolates. Further studies are warranted to evaluate the potential clinical utility of omadacycline for nocardiosis.

Sequence- and Structure-Dependent Cytotoxicity of Phosphorothioate and 2'-O-Methyl Modified Single-Stranded Oligonucleotides

Single-stranded oligonucleotides (SSOs) are a rapidly expanding class of therapeutics that comprises antisense oligonucleotides, microRNAs, and aptamers, with ten clinically approved molecules. Chemical modifications such as the phosphorothioate backbone and the 2'-O-methyl ribose can improve the stability and pharmacokinetic properties of therapeutic SSOs, but they can also lead to toxicity in vitro and in vivo through nonspecific interactions with cellular proteins, gene expression changes, disturbed RNA processing, and changes in nuclear structures and protein distribution. In this study, we screened a mini library of 277 phosphorothioate and 2'-O-methyl-modified SSOs, with or without mRNA complementarity, for cytotoxic properties in two cancer cell lines. Using circular dichroism, nucleic magnetic resonance, and molecular dynamics simulations, we show that phosphorothioate- and 2'-O-methyl-modified SSOs that form stable hairpin structures through Watson-Crick base pairing are more likely to be cytotoxic than those that exist in an extended conformation. In addition, moderate and highly cytotoxic SSOs in our dataset have a higher mean purine composition than pyrimidine. Overall, our study demonstrates a structure-cytotoxicity relationship and indicates that the formation of stable hairpins should be a consideration when designing SSOs toward optimal therapeutic profiles.

Systematic review of non-invasive ventilation and craniofacial fractures: a multidisciplinary perspective and recommendations for management

The anatomically complex craniofacial skeleton demands special consideration when caring for cases of polytrauma or medically compromised patients with craniofacial fractures. This paper utilises a systematic review and multidisciplinary opinions to create an algorithm for the hospital-based care of patients with craniofacial fractures (base of skull, orbit, paranasal sinus, and mandible) who require non-invasive ventilation (NIV). Each fracture location has a unique predisposition to a different type of emphysema and associated morbidity. The risk of developing emphysema, combined with its potential severity, is stratified against the harm of not providing NIV for the holistic care of the patient. The aim of this paper is to synthesise evidence from a systematic review of existing literature with multidisciplinary opinions to develop a concise algorithm that outlines the optimal treatment of patients with craniofacial fractures who require NIV.

Dynamics and recognition of homeodomain containing protein-DNA complex of IRX4

Iroquois Homeobox 4 (IRX4) belongs to a family of homeobox TFs having roles in embryogenesis, cell specification, and organ development. Recently, large scale genome-wide association studies and epigenetic studies have highlighted the role of IRX4 and its associated variants in prostate cancer. No studies have investigated and characterized the structural aspect of the IRX4 homeodomain and its potential to bind to DNA. The current study uses sequence analysis, homology modeling, and molecular dynamics simulations to explore IRX4 homeodomain-DNA recognition mechanisms and the role of somatic mutations affecting these interactions. Using publicly available databases, gene expression of IRX4 was found in different tissues, including prostate, heart, skin, vagina, and the protein expression was found in cancer cell lines (HCT166, HEK293), B cells, ascitic fluid, and brain. Sequence conservation of the homeodomain shed light on the importance of N- and C-terminal residues involved in DNA binding. The specificity of IRX4 homodimer bound to consensus human DNA sequence was confirmed by molecular dynamics simulations, representing the role of conserved amino acids including R145, A194, N195, S190, R198, and R199 in binding to DNA. Additional N-terminal residues like T144 and G143 were also found to have specific interactions highlighting the importance of N-terminus of the homeodomain in DNA recognition. Additionally, the effects of somatic mutations, including the conserved Arginine (R145, R198, and R199) residues on DNA binding elucidated the importance of these residues in stabilizing the protein-DNA complex. Secondary structure and hydrogen bonding analysis showed the roles of specific residues (R145, T191, A194, N195, R198, and R199) in maintaining the homogeneity of the structure and its interaction with DNA. The differences in relative binding free energies of all the mutants shed light on the structural modularity of this protein and the dynamics behind protein-DNA interaction. We also have predicted that the C-terminal sequence of the IRX4 homeodomain could act as a potential cell-penetrating peptide, emphasizing the role these small peptides could play in targeting homeobox TFs.

Evaluating the sensitivity and specificity of dried blood spots for serological testing of HIV, syphilis, hepatitis B and C Elecsys assays on the Roche Cobas system

This study was performed to validate a dried blood spot (DBS) method for the serological screening of HIV, syphilis, hepatitis B and C. It included 250 paired DBS and serum samples and 116 unpaired DBS samples from 366 unique patients from two laboratories between 8 October and 2 November 2021. As determined by original test request, these were tested using a DBS method for HIV Ag/Ab (n=216), anti-treponemal Ab (n=166), hepatitis B sAg (n=100), and hepatitis C Ab (n=100) Elecsys assays on the Roche Cobas automated platform. Using the manufacturer's (serum) cut-off for reactivity ('positivity'), the sensitivity and specificity of DBS testing compared with serum were: for HIV Ag/Ab 100% and 100%, for anti-treponemal Ab 68.3% and 100%, for hepatitis B sAg 95.9% and 100%, and for hepatitis C Ab 84.0% and 100%, respectively. Adjusting the assay cut-off using receiver operator curve analysis increased sensitivity of DBS testing for anti-treponemal Ab to 90.0%, hepatitis B sAg to 97.9% and hepatitis C Ab to 94.0% whilst maintaining specificity of 98.8%, 100% and 100%, respectively. With optimisation of assay cut-off, DBS can perform comparably with serum for serological testing for HIV, syphilis, hepatitis B and C and may be a valuable tool in increasing access to testing in New Zealand.

Targeting the COMMD4-H2B protein complex in lung cancer

BACKGROUND

Lung cancer is the biggest cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 85-90% of all lung cancers. Identification of novel therapeutic targets are required as drug resistance impairs chemotherapy effectiveness. COMMD4 is a potential NSCLC therapeutic target. The aims of this study were to investigate the COMMD4-H2B binding pose and develop a short H2B peptide that disrupts the COMMD4-H2B interaction and mimics COMMD4 siRNA depletion.

METHODS

Molecular modelling, in vitro binding and site-directed mutagenesis were used to identify the COMMD4-H2B binding pose and develop a H2B peptide to inhibit the COMMD4-H2B interaction. Cell viability, DNA repair and mitotic catastrophe assays were performed to determine whether this peptide can specially kill NSCLC cells.

RESULTS

Based on the COMMD4-H2B binding pose, we have identified a H2B peptide that inhibits COMMD4-H2B by directly binding to COMMD4 on its H2B binding binding site, both in vitro and in vivo. Treatment of NSCLC cell lines with this peptide resulted in increased sensitivity to ionising radiation, increased DNA double-strand breaks and induction of mitotic catastrophe in NSCLC cell lines.

CONCLUSIONS

Our data shows that COMMD4-H2B represents a novel potential NSCLC therapeutic target.

The potential impact of periodontitis on cerebral small vessel disease

Cerebral small vessel disease (CSVD) is a term used to describe abnormalities in the intracranial microvasculature affecting small arteries, arterioles, capillaries, and venules. The etiology of these conditions is not fully understood but inflammation appears to play a significant role. Periodontal diseases have been associated with conditions such as stroke and dementia, which are clinical consequences of CSVD. Periodontitis is a highly prevalent chronic multifactorial inflammatory disease regulated by the host immune response against pathogenic bacterial colonization around the teeth. The inflammatory response and the microbial dysbiosis produce pro-inflammatory cytokines that can reach the brain and promote local changes. This review will explore the potential association between periodontitis and CSVD by assessing the impact of periodontitis-induced inflammation and periodontopathogenic bacteria on the underlying mechanisms leading to CSVD. Given the association of periodontitis with stroke and dementia, which are clinical features of CSVD, it may be possible to suggest a link with CSVD. Current evidence linking periodontitis with neuroimaging findings of CSVD enforces the possible link between these conditions.

Determinants of lipid clinic referral and attendance in a multi-ethnic adult population in south London: a cross-sectional study

BACKGROUND

Primary dyslipidaemias, including familial hypercholesterolaemia, are underdiagnosed genetic disorders that substantially increase risk for premature coronary artery disease in adults. Early identification of primary dyslipidaemias via lipid clinic referral optimises patient management and enables cascade screening of relatives. Improving the identification of primary dyslipidaemias, and understanding disparities in ascertainment and management, is an NHS priority. We aimed to assess determinants of lipid clinic referral or attendance (LCR) in ethnically diverse adults.

METHODS

We did a retrospective cross-sectional study using the Lambeth DataNet containing anonymised data from 41 general practitioner (GP) practices in south London. We looked at referral data for adult patients aged 18 years and older from Jan 1, 1995, until May 14, 2018. LCR was the main outcome. We used sequential multilevel logistic regression models adjusted for practice effects to estimate the odds of LCR assessed across six ethnic groups (reference group White) and patient-level factors (demographic, socioeconomic, lifestyle, comorbidities, total cholesterol [TC] >7·5mmol/L, statin prescription, and practice factors). The study was approved by NHS South East London Clinical Commissioning Group (CCG) and NHS Lambeth CCG.

FINDINGS

780 (0·23%) of 332 357 adult patients were coded as referred (n=538) or seen (n=252) in a lipid clinic. 164 487 (46·49%) were women (appendix). The fully adjusted model for odds of LCR showed the following significant associations for age (odds ratio [OR] 0·96, 95% CI 0·96-0·97, p<0·001); Black, African, Caribbean, or Black-British ethnicity (0·67, 0·53-0·84, p=0·001); ex-smoker status (1·29, 1·05-1·57, p=0·014); TC higher than 7·5 mmol/L (12·18, 9·60-15·45, p<0·001); statin prescription (14·01, 10·85-18·10, p<0·001); diabetes (0·72, 0·58-0·91, p=0·005); high-frequency GP attendance at seven or more GP consultations in the past year (1·49, 1·21-1·84, p<0·001); high GP-density (0·5-0·99 full-time equivalent GPs per 1000 patients; 2·70, 1·23-5·92, p=0·013). Sensitivity analyses for LCR restricted to familial hypercholesterolaemia-coded patients (n=581) found associations with TC higher than 7·5 mmol/L (4·26, 1·89-9·62, p<0·001), statin prescription (16·96, 2·19-131·36, p=0·007), and high GP-density (5·73, 1·27-25·93, p=0·023), with no significant associations with ethnicity. The relative contribution of GP practices to LCR was 6·32% of the total variance. There were no significant interactions between ethnicity and deprivation, age, or obesity.

INTERPRETATION

While interpretation is limited by the accuracy and completeness of coded records, the study showed factors associated with a higher likelihood of LCR included individuals recorded as having TC higher than 7·5 mmol/L, statin prescription, ex-smoker status, high-frequency GP attendance, and registration at a GP practice with 0·5-0·99 GP density. Patients with increasing age; Black, African, Caribbean, or Black-British ethnicity patients; and patients with diabetes had lower odds of LCR. Finally, the difference in odds of LCR between Black and White patients highlights potential health inequalities.

FUNDING

NHS Race & Health Observatory.

Quality of life in people living with HIV in Aotearoa New Zealand: an exploratory cross-sectional study

Quality of life (QoL) in people living with HIV (PLHIV) is reportedly worse than in people without HIV, with many factors impacting on this. We aimed to investigate QoL in PLHIV in New Zealand (NZ). In-person interviews were conducted including socio-demographic, health, social connectedness, and stigma-related questions. QoL was measured using the 13-question PozQoL Scale - summed to give a score between 13 and 65. Univariate linear regression was used to investigate factors associated with differences in PozQoL scores. PLHIV (n = 188) of different ethnicities from throughout NZ participated. The mean age was 47 years; 65% were men; 61% were men who have sex with men; 61% had been living with HIV for ≥10 years. The mean summary PozQoL score was 47.16. Factors associated with a lower mean PozQol included no sex in the last 12 months (-9.03), inability to meet basic needs (-7.47), ever (-6.49) or recently (-5.03), experiencing stigma or discrimination, mental health condition (-5.74), HIV diagnosis <5 years (-5.48), poor health (-5.43), being unemployed (-5.02), not having support (-4.71), and greater internalised stigma (-2.81). Improving QoL will require investment in peer support and community welfare programmes to better support PLHIV, and stigma reduction campaigns targeting the broader community.

A descriptive analysis of first trimester urinary concentrations of 14 bisphenol analogues in the MIREC Canadian pregnancy cohort

BACKGROUND

Concern over the health effects of BPA, particularly for the developing fetus, has led to an increasing use of bisphenol analogues in industrial and consumer products, which may be as hormonally active as BPA. Biomonitoring data for many bisphenol analogues, especially in pregnant populations, are limited.

METHODS

We measured concentrations of 14 bisphenol analogues in 1st trimester urine samples (n = 1851) from the Maternal-Infant Research on Environmental Chemicals (MIREC) Canadian pregnancy cohort (2008-2011). We examined patterns of exposure according to sociodemographic and sampling characteristics as well as occupation and frequency of consumption of canned fish within the previous 3 months.

RESULTS

BPA was detected in 89% of participants with a specific gravity standardized geometric mean concentration of 0.990 μg/L. Biphenol 4,4' (BP 4,4'), 4,4'-dihydroxydiphenyl ether (DHDPE), and bisphenol E (BPE) were detected in >97% of participants. Bisphenol F (BPF) and bisphenol S (BPS) were detected in >60% of participants. Specific gravity standardized geometric mean concentrations of these 5 compounds ranged from 0.024 to 0.564 μg/L. Nine bisphenol analogues were detected in <9% of participants. Concentrations of BP 4,4', DHDPE, and BPE were higher in younger women and those with higher pre-pregnancy BMI, lower household income, lower education, and among smokers. We found a similar pattern of differences in BPF for age, education, and smoking status while BPS similarly differed across categories of pre-pregnancy BMI. Participants who were unemployed or working in the service industry had higher molar sum of 7 bisphenol analogues than those working in healthcare, education, or an office setting. Canned fish consumption was not related to bisphenol analogue concentrations.

CONCLUSION

BP 4,4', DHDPE, BPE, BPF, and BPS were highly detected in 1st trimester urine samples in this large pan-Canadian pregnancy cohort. This suggests widespread exposure to these analogues around 2008-2011 and warrants further investigation into associations with health outcomes.

Determinants of lipid-lowering medication prescribing in a multi-ethnic adult population diagnosed with familial hypercholesterolaemia in South London

BACKGROUND

Familial hypercholesterolaemia (FH) (prevalence 1 in 250) is an inherited condition that significantly increases risk of premature cardiovascular disease. Early diagnosis can potentially normalise cardiovascular risk with lipid-lowering medicines (statins and fibrates). Only 7% of patients with FH are identified in the UK. Improving identification, and understanding disparities in ascertainment and management, is an NHS priority.

AIM

To assess determinants of lipid-lowering prescribing in ethnically diverse adults with an FH code. METHOD: Retrospective cross-sectional analysis of Lambeth DataNet, containing anonymised adult patient data from 41 practices in South London. Stata 17 was used to run sequential multilevel logistic regression models, adjusted for practice effects, to estimate the odds of no lipid-lowering prescription in FH-coded adults; this was assessed across 10 ethnic groups and other patient-level factors: demographic, socioeconomic, lifestyle, comorbidities, and practice factors (consultation frequency and practice list size).

RESULTS

One hundred and sixty-one of 801 (20%) of adults with an FH code received no lipid-lowering medication. The fully adjusted model for no lipid-lowering prescriptions showed the following associations: age (years) odds ratio (OR) 0.93 (P<0.001, 95% confidence interval [CI] = 0.91 to 0.95), male sex OR 0.47 (P = 0.002, 95% CI = 0.29 to 0.76), diabetes OR 0.26 (P = 0.04, 95% CI = 0.70 to 0.96), hypertension OR 0.30 (P<0.01, 95% CI = 0.12 to 0.72), and frequency of GP attendance OR 0.48 (P = 0.03, 95% CI = 0.24 to 0.94). Sensitivity analyses examining determinants of high-intensity statin prescribing found similar results.

CONCLUSION

The study suggests important determinants of lipid-lowering prescribing in an ethnically diverse adult population included older age, male sex, hypertension, and diabetes. Ethnicity showed no significant associations with lipid-lowering prescribing after adjusting for other determinants including deprivation measures.

Saddle Thigh Block Design Can Influence Rider and Horse Biomechanics

The association between rider-saddle interaction and horse kinematics has been little studied. It was hypothesized that differences in a thigh block design would influence (a) rider-saddle interface pressures, (b) rider kinematics, and (c) equine limb/spinal kinematics. Eighteen elite sport horses/riders were trotted using correctly fitted dressage saddles with thigh blocks S (vertical face) and F (deformable face). Contact area, mean, and peak pressure between rider and saddle were determined using an on-saddle pressure mat. Spherical markers allowed for the measurement of horse/rider kinematics using two-dimensional video analysis. The kinematics of the equine thoracolumbosacral spine were obtained using skin-mounted inertial measuring units. Results were compared between thigh blocks (paired t-test p ≤ 0.05). With F, the contact area, mean, and peak pressure between rider and saddle were significantly higher (p = 0.0001), and the rider trunk anterior tilt was reduced, indicating altered rider-saddle interaction. The horse thoracic axial rotation and flexion/extension were reduced (p = 0.01-0.03), caudal thoracic and lumbar lateral bend was increased (p = 0.02-0.04), and carpal flexion increased (p = 0.01-0.05) with F compared to S. During straight-line locomotion when in sitting trot, thigh block F was associated with altered rider-saddle interaction and rider and equine kinematics, leading to a more consistent rider-saddle interface, a more upright rider trunk during stance, an increased horse thoracic stability and lumbar lateral bend, and forelimb flexion, supporting the importance of optimising rider-saddle-horse interaction.

New insights into cognitive decline in chronic kidney disease

Chronic kidney disease (CKD) is known to be associated with cognitive impairment, but the mechanisms that underlie this kidney–brain connection are unclear. A recent study provides evidence that CKD is an independent risk factor for cognitive decline due to cerebral small vessel disease.

Neuropathology of microbleeds in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral microbleeds (CMBs) detected on magnetic resonance imaging are common in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The neuropathologic correlates of CMBs are unclear. In this study, we characterized findings relevant to CMBs in autopsy brain tissue of 8 patients with genetically confirmed CADASIL and 10 controls within the age range of the CADASIL patients by assessing the distribution and extent of hemosiderin/iron deposits including perivascular hemosiderin leakage (PVH), capillary hemosiderin deposits, and parenchymal iron deposits (PID) in the frontal cortex and white matter, basal ganglia and cerebellum. We also characterized infarcts, vessel wall thickening, and severity of vascular smooth muscle cell degeneration. CADASIL subjects had a significant increase in hemosiderin/iron deposits compared with controls. This increase was principally seen with PID. Hemosiderin/iron deposits were seen in the majority of CADASIL subjects in all brain areas. PVH was most pronounced in the frontal white matter and basal ganglia around small to medium sized arterioles, with no predilection for the vicinity of vessels with severe vascular changes or infarcts. CADASIL subjects have increased brain hemosiderin/iron deposits but these do not occur in a periarteriolar distribution. Pathogenesis of these lesions remains uncertain.

Structural investigation of CDCA3-Cdh1 protein-protein interactions using in vitro studies and molecular dynamics simulation

The anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase and its cofactor, Cdh1, regulate the expression of several cell-cycle proteins and their functions during mitosis. Levels of the protein cell division cycle-associated protein 3 (CDCA3), which is functionally required for mitotic entry, are regulated by APC/C^Cdh1 . CDCA3 is an intrinsically disordered protein and contains both C-terminal KEN box and D-box recognition motifs, enabling binding to Cdh1. Our previous findings demonstrate that CDCA3 has a phosphorylation-dependent non-canonical ABBA-like motif within the linker region bridging these two recognition motifs and is required for efficient binding to Cdh1. Here, we sought to identify and further characterize additional residues that participate within this ABBA-like motif using detailed in vitro experiments and in silico modeling studies. We identified the role of H-bonds, hydrophobic and ionic interactions across the CDCA3 ABBA-like motif in the linker region between KEN and D-box motifs. This linker region adopts a well-defined structure when bound to Cdh1 in the presence of phosphorylation. Upon alanine mutation, the structure of this region is lost, leading to higher flexibility, and alteration in affinities due to binding to alternate sites on Cdh1. Our findings identify roles for the anchoring residues in the non-canonical ABBA-like motif to promote binding to the APC/C^Cdh1 and regulation of CDCA3 protein levels.

Chronic kidney disease promotes cerebral microhemorrhage formation

BACKGROUND

Chronic kidney disease (CKD) is increasingly recognized as a stroke risk factor, but its exact relationship with cerebrovascular disease is not well-understood. We investigated the development of cerebral small vessel disease using in vivo and in vitro models of CKD.

METHODS

CKD was produced in aged C57BL/6J mice using an adenine-induced tubulointerstitial nephritis model. We analyzed brain histology using Prussian blue staining to examine formation of cerebral microhemorrhage (CMH), the hemorrhagic component of small vessel disease and the neuropathological substrate of MRI-demonstrable cerebral microbleeds. In cell culture studies, we examined effects of serum from healthy or CKD patients and gut-derived uremic toxins on brain microvascular endothelial barrier.

RESULTS

CKD was induced in aged C57BL/6J mice with significant increases in both serum creatinine and cystatin C levels (p < 0.0001) without elevation of systolic or diastolic blood pressure. CMH was significantly increased and positively correlated with serum creatinine level (Spearman r = 0.37, p < 0.01). Moreover, CKD significantly increased Iba-1-positive immunoreactivity by 51% (p < 0.001), induced a phenotypic switch from resting to activated microglia, and enhanced fibrinogen extravasation across the blood-brain barrier (BBB) by 34% (p < 0.05). On analysis stratified by sex, the increase in CMH number was more pronounced in male mice and this correlated with greater creatinine elevation in male compared with female mice. Microglial depletion with PLX3397 diet significantly decreased CMH formation in CKD mice without affecting serum creatinine levels. Incubation of CKD serum significantly reduced transendothelial electrical resistance (TEER) (p < 0.01) and increased sodium fluorescein permeability (p < 0.05) across the endothelial monolayer. Uremic toxins (i.e., indoxyl sulfate, p-cresyl sulfate, and trimethylamine-N-oxide) in combination with urea and lipopolysaccharide induced a marked drop in TEER compared with the control group (p < 0.0001).

CONCLUSIONS

CKD promotes the development of CMH in aged mice independent of blood pressure but directly proportional to the degree of renal impairment. These effects of CKD are likely mediated in part by microglia and are associated with BBB impairment. The latter is likely related to gut-derived bacteria-dependent toxins classically associated with CKD. Overall, these findings demonstrate an important role of CKD in the development of cerebral small vessel disease.

Abstract TP223: Cerebral Microbleeds In Sickle Cell Disease

Introduction: Stroke due to sickle cell disease is often attributed to large vessel involvement in the disorder. The role of cerebral microvascular disease in sickle cell disease has received little attention. In this study, we examined development of cerebral microvascular lesions in a mouse model of sickle cell disease. We focused on cerebral microhemorrhages, the neuropathologic substrate of cerebral microbleeds.

Methods: We studied microvascular disease in a well-characterized mouse model of humanized transgenic sickle (HbSS-BERK) and control (HbAA-BERK) mice expressing >99% human sickle hemoglobin (Hb) and normal human HbA, respectively. HbSS-BERK express human α and βS globins on a mixed genetic background. HbAA-BERK mice express normal human α and βA globin thus producing only normal human hemoglobin A, on the same mixed genetic background as HbSS-BERK. Seven- to nine-month-old mice (N=18 HbSS, N=12 HbAA) were examined. We collected mouse brains and performed standard histology using Prussian blue staining to detect CMH formation at 20x magnification. The average number, total area, and size of Prussian blue-positive deposits were quantified. In separate studies, Toluidine Blue staining was used to identify mast cells.

Results: HbSS mice showed approximately 70% more cerebral microhemorrhages than controls (mean±SE of 1.17± 0.22 vs 0.69±0.13 number/cm 2, p=0.04). Lesion size did not differ between HbSS and control mice. Activated mast cells were identified in HbSS mouse brain but not in control mice.

Conclusions: In this mouse model of sickle cell disease, HbSS mice demonstrated significantly increased development of cerebral microhemorrhages. These findings emphasize the potential importance of cerebral microvascular disease in sickle cell disease. Cerebral mast cell activation in sickle cell disease may be a novel target for investigation.

Arteriolar neuropathology in cerebral microvascular disease

Cerebral microvascular disease (MVD) is an important cause of vascular cognitive impairment. MVD is heterogeneous in aetiology, ranging from universal ageing to the sporadic (hypertension, sporadic cerebral amyloid angiopathy [CAA] and chronic kidney disease) and the genetic (e.g., familial CAA, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL] and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy [CARASIL]). The brain parenchymal consequences of MVD predominantly consist of lacunar infarcts (lacunes), microinfarcts, white matter disease of ageing and microhaemorrhages. MVD is characterised by substantial arteriolar neuropathology involving ubiquitous vascular smooth muscle cell (SMC) abnormalities. Cerebral MVD is characterised by a wide variety of arteriolar injuries but only a limited number of parenchymal manifestations. We reason that the cerebral arteriole plays a dominant role in the pathogenesis of each type of MVD. Perturbations in signalling and function (i.e., changes in proliferation, apoptosis, phenotypic switch and migration of SMC) are prominent in the pathogenesis of cerebral MVD, making 'cerebral angiomyopathy' an appropriate term to describe the spectrum of pathologic abnormalities. The evidence suggests that the cerebral arteriole acts as both source and mediator of parenchymal injury in MVD.

Abstract TP198: Periodontitis Enhances Cerebral Microhemorrhage Development In A Mouse Model Of Hypertension

Introduction: Periodontitis is a highly prevalent disorder that is increasingly recognized as a risk factor for cerebrovascular disease. In this study we examined the role of periodontitis in the development of cerebral microvascular disease.

Methods: Hypertension was induced in aged (17 months old) male C57BL/6J mice via infusion of angiotensin II (ATII) at 1000 ng/kg/min via Alzet pump over 4 weeks. Periodontitis was induced by giving P. gingivalis -LPS (20 μg in 2 μL) injections between the first and second maxillary molars on both the right and left sides twice a week for six weeks. At end of six weeks, we collected mouse brains (N=5 each for Hypertension, Periodontitis, Hypertension + Periodontitis, and Control) and performed standard histology using Prussian blue staining to detect cerebral microhemorrhages (CMH) formation at 20x magnification. The average number, total area, and size of Prussian blue-positive deposits were quantified.

Results: ATII-induced hypertension in animals (Systolic blood pressure: 113±2 mmHg to 156±3 mmHg, mean+SE, p<0.0001; Diastolic blood pressure: 82±2 mmHg to 119±3 mmHg, p<0.0001). Presence of hypertension produced significant increase in number of CMH compared to controls (1.97±0.29 per cm 2 vs. 1.24±0.20 per cm 2 , p<0.05). Presence of periodontitis did not alter the number of microhemorrhages (1.68±0.13 per cm 2 vs.1.97±0.29 per cm 2 ). However, size of microhemorrhages doubled in the presence of periodontitis with hypertension (10.58±2.55 μm 2 per cm 2 vs. 5.05±1.15 μm 2 per cm 2 , p<0.05).

Conclusions: In this mouse model of ATII-induced hypertension, periodontitis appears to increase size of CMH rather than induce development of new lesions. These findings suggest a role for periodontitis in cerebrovascular disease by modifying and exacerbating pre-existing stroke risk factors rather than acting as an independent risk factor.

Paediatric Society and Hyperinsulinism Charity National Surveys on CGM Access for Patients With Recurrent Hypoglycaemia

Context

Recurrent hypoglycemia can result in significant neurological impairments in children and continuous glucose monitoring (CGM) technology has been shown to reduce recurrent hypoglycemia in conditions such as type 1 diabetes. In the United Kingdom, CGM devices are currently only recommended by the National Institute of Clinical Excellence (NICE) for patients with diabetes and not for other diagnoses.

Objective

To examine access to CGM technology for children and young people with recurrent hypoglycemia in the United Kingdom.

Methods

In 2021, the British Society of Paediatric Endocrinology and Diabetes (BSPED) conducted a national health professional survey in England, Wales, Scotland, and Northern Ireland looking at CGM access to funding for children and young people with recurrent hypoglycemia, without the diagnosis of diabetes. The UK Children's Hyperinsulinism Charity (UK CHC) also conducted a national patient survey.

Results

Responses from BSPED were received from 55 units while the UK CHC received 69 responses from individual families, the largest response to a survey carried out by the charity. The results of the BSPED and UK CHC surveys found that funding streams for CGM were highly variable. Only 29% were able to access CGM for recurrent hypoglycemia and from these, 65% were self-funding CGM. Quality of life benefits were evident from the UK CHC survey on the utility of CGM in reducing worry, improving sleep, lessening the burden of frequently finger-pricking and reducing out-of-hours appointments as a result of hypoglycemia. Patient-reported utilization rates of blood glucose test strips per week were significantly reduced.

Conclusion

BSPED and UK CHC national surveys support a call and a consideration for CGM access to be widened to patients who suffer from recurrent hypoglycemia such as those with hyperinsulinism or metabolic conditions. The prevention of recurrent hypoglycemia and improving quality of life for patients and carers remain a cornerstone management for people who suffer from frequent hypoglycemia. CGM education is critical to support its use and understand its limitations. Further research is warranted to determine the safety and efficacy of CGM in detection and reduction of hypoglycemic events, impact of hospital stay, and long-term neurological outcomes in those who suffer from recurrent hypoglceamia.

Local zinc treatment enhances fracture callus properties in diabetic rats

The effects of locally applied zinc chloride (ZnCl₂ ) on early and late-stage parameters of fracture healing were evaluated in a diabetic rat model. Type 1 Diabetes has been shown to negatively impact mechanical parameters of bone as well as biologic markers associated with bone healing. Zinc treatments have been shown to reverse those outcomes in tests of nondiabetic and diabetic animals. This study is the first to assess the efficacy of a noncarrier mediated ZnCl₂ on bony healing in diabetic animals. This is a promising basic science approach which may lead to benefits for diabetic patients in the future. Treatment and healing were assessed through quantification of callus zinc, radiographic scoring, microcomputed tomography (µCT), histomorphometry, and mechanical testing. Local ZnCl₂ treatment increased callus zinc levels at 1 and 3 days after fracture (p ≤ 0.025). Femur fractures treated with ZnCl₂ showed increased mechanical properties after 4 and 6 weeks of healing. Histomorphometry of the ZnCl₂ -treated fractures found increased callus cartilage area at Day 7 (p = 0.033) and increased callus bone area at Day 10 (p = 0.038). In contrast, callus cartilage area was decreased (p < 0.01) after 14 days in the ZnCl₂ -treated rats. µCT analysis showed increased bone volume in the fracture callus of ZnCl₂ -treated rats at 6 weeks (p = 0.0012) with an associated increase in the proportion of µCT voxel axial projections (Z-rays) spanning the fracture site. The results suggest that local ZnCl₂ administration improves callus chondrogenesis leading to greater callus bone formation and improved fracture healing in diabetic rats.

Prywatyzacja stresu

W artykule Mark Fisher rozwija przedstawioną w Realizmie kapitalistycznym z 2008 roku intuicję dotyczącą związku, jaki zachodzi między neoliberalizmem (niszczeniem związków zawodowych, prywatyzacją usług publicznych, „uelastycznieniem” rynku pracy), jego ideologicznym usprawiedliwieniem (Thatcherowskie „nie ma alternatywy”) a zdrowiem psychicznym, zwłaszcza jego medykalizacją i prywatyzacją. Zdaniem Fishera lewicowym remedium na opisywane w zasadniczej części artykułu problemy nie jest kopiowanie przeszłych form organizacji politycznej, lecz powrót do projektu „lewicowego modernizmu”, który tak naprawdę nigdy nie został zrealizowany.

Delineation of blacktip shark (Carcharhinus limbatus) nursery habitats in the north-western Gulf of Mexico

Coevolution with predators leads to the use of low-risk habitats by many prey species, which promotes survival during early developmental phases. These nurseries are valued by conservation and management agencies because of their contributions to adult populations. However, the physical and geographic characteristics, like shallow depths and isolation from other marine habitats, that restrict access to predators and thereby reduce risk to juvenile animals can also limit scientific research. Consequently, many nursery habitats are still unidentified and understudied. Here we used gillnet monitoring from 1982 to 2018 to delineate blacktip shark (Carcharhinus limbatus) nurseries in the north-western Gulf of Mexico and elucidated their physical, environmental and biological characteristics. Nursery habitats within estuaries (<2% of spatial area) were proximate to the Gulf of Mexico and exhibited significantly lower variability in salinity than non-nurseries. However, relative abundances of predators and prey were not significant delineators of nursery habitats. As such, food and risk may not influence juvenile blacktip habitat use as expected. Alternatively, reduced osmoregulatory stress attributed to predictable environments likely provides advantageous conditions for blacktips to develop foraging and antipredator tactics, which is vital prior to the winter migration of juvenile sharks into the Gulf of Mexico.

AB0093 MODELING OF ANTIGEN-COLLAGEN-INDUCED ARTHRITIS IN BALB/c MICE

Background

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases. Currently, disease-modifying drugs and biological agents are used to treat RA [1]. The available drugs are not perfect: they have serious side effects and do not always cause a stable improvement or remission [2]. The above sets the task of finding new approaches to treatment that will be effective, more specific and safe. In this connection, it is necessary to develop and apply experimental models as close as possible in pathogenesis to rheumatoid arthritis. One such model, rarely used at present, is the combined antigen-collagen-induced arthritis [3].

Objectives

To show immunological and histological changes similar to RA in the AIA/CIA model and the validity of its application in research activities.

Methods

Experimental AIA/CIA was induced according to 2 different protocols in 50 BALB/c mice. Clinical assessment of arthritis was made by measuring the swelling of the paws with a caliper at different times. The assessment of immunological changes included the analysis of the content of antibodies to type II collagen by ELISA, the content of T-regulatory cells by flow cytometry. Also, a histological analysis of the obtained data was carried out.

Results

On the 10th day, a significant increase in paw thickness was recorded in animals induced both according to the first and second protocols. The intensity of swelling subsided by the 23rd day. A significant increase in the content of antibodies to type II collagen was observed in all experimental groups, but in animals from Protocol No. 1, the amount of antibodies to type II collagen was significantly higher. A high level of T-regulatory cells was registered only in mice induced according to the first protocol on the 10th day. Histological changes in the form of synovial hyperplasia, pannus, usurations were observed to varying degrees in all experimental groups, but the most pronounced changes were in animals from the first protocol.

Conclusion

In experimental animals, in all the presented protocols, changes were observed that were closest to RA, when compared with classical models of experimental arthritis induction. Based on the fact that protocol 1 animals showed an increase in the content of T-regulatory cells, the levels of antibodies to type 2 collagen were consistently high, and the histological changes were the most pronounced, it can be assumed that protocol 1 of the combined AIA/CIA model on the line of Balb/c mice, is the most suitable for testing and developing new methods of RA therapy.

References

[1]Abbasi M, Mousavi MJ, Jamalzehi S, Alimohammadi R, Bezvan MH, Mohammadi H, Aslani S. Strategies toward rheumatoid arthritis therapy; the old and the new. J Cell Physiol. 2019 Jul;234(7):10018-10031. doi: 10.1002/jcp.27860. Epub 2018 Dec 7. PMID: 30536757.

[2]Greenberg JD, Reed G, Kremer JM, Tindall E, Kavanaugh A, Zheng C, Bishai W, Hochberg MC; CORRONA Investigators. Association of methotrexate and tumour necrosis factor antagonists with risk of infectious outcomes including opportunistic infections in the CORRONA registry. Ann Rheum Dis. 2010 Feb;69(2):380-6. doi: 10.1136/ard.2008.089276. Epub 2009 Apr 8. PMID: 19359261; PMCID: PMC2861900.

[3]Baddack U, Hartmann S, Bang H, Grobe J, Loddenkemper C, Lipp M, Müller G. A chronic model of arthritis supported by a strain-specific periarticular lymph node in BALB/c mice. Nat Commun. 2013;4:1644. doi: 10.1038/ncomms2625. PMID: 23552059; PMCID: PMC3644064

Disclosure of Interests

None declared

Current Practices in Dorsal Augmentation Rhinoplasty

BACKGROUND

Dorsal augmentation rhinoplasty addresses the aesthetic and functional impairments caused by a deficient nasal dorsum. Augmentation rhinoplasty can be performed using a variety of different surgical techniques and grafting materials that all have distinct advantages and disadvantages.

METHODS

Grafting materials have unique characteristics, uses, and safety profiles. A detailed overview of various grafting materials and their uses, risks, and benefits is provided.

RESULTS

Autologous grafting materials include septal cartilage, auricular cartilage, and costal cartilage. These donor sites can provide various amounts of en bloc or diced cartilage. Alternatively, bone may be used when strong structural stability is required, and soft tissue may be used to fill mild to moderate defects. Homologous grafts (e.g., irradiated and nonirradiated rib) and acellular dermal matrices are alternatives to autologous graft with many similar advantages and no need for an additional surgical site. Lastly, alloplastic implants may be successfully used for dorsal augmentation if both patient and surgeon understand their associated risks.

CONCLUSION

To perform successful dorsal augmentation, surgeons should be familiar with the wide variety of operative approaches and augmentation materials that are currently available and understand their risks, benefits, and uses.

Magnetic Resonance Imaging Findings in High School Football Players: Brain and Cervical Spine

Football exposes its players to traumatic brain, neck, and spinal injury. It is unknown whether the adolescent football player develops imaging abnormalities of the brain and spine that are detectable on magnetic resonance imaging (MRI). The objective of this observational study was to identify potential MRI signatures of early brain and cervical spine (c-spine) injury in high school football players. Eighteen football players (mean age, 17.0 ± 1.5 years; mean career length, 6.3 ± 4.0 years) had a baseline brain MRI, and 7 had a follow-up scan 9–42 months later. C-spine MRIs were performed on 11 of the 18 subjects, and 5 had a follow-up scan. C-spine MRIs from 12 age-matched hospital controls were also retrospectively retrieved. Brain MRIs were reviewed by a neuroradiologist, and no cerebral microbleeds were detected. Three readers (a neuroradiologist, a neurosurgeon, and an orthopedic spine surgeon) studied the cervical intervertebral discs at six different cervical levels and graded degeneration using an established five-grade scoring system. We observed no statistically significant difference in disc degeneration or any trend toward increased disc degeneration in the c-spine of football players as compared with age-matched controls. Further research is needed to validate our findings and better understand the true impact of contact sports on young athletes.

Examining the trajectory and predictors of post-concussion sleep quality in children and adolescents

OBJECTIVES

This study aimed to 1) determine if post-concussion sleep quality of children and adolescents differed from healthy sleep estimates; 2) describe the trajectory of parameters of sleep quality; 3) determine factors that predict sleep quality outcomes; and 4) compare sleep parameter outcomes between asymptomatic and symptomatic participants at 4 weeks post-concussion.

METHODS

Nightly actigraphy estimates of sleep in 79 children and adolescents were measured throughout 4 weeks post-concussion. Total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), number of arousals (NOA), and average arousal length (AAL) were measured.

RESULTS

Child and adolescent participants experienced significantly poorer SE and longer WASO duration throughout 4 weeks of recovery and adolescents experienced significantly longer TST. SE significantly improved with time post-injury (p = .047). Older age was associated with longer TST (p = .003) and female sex was associated with longer WASO (p = .025) and AAL duration (p = .044). Week 4 sleep parameter outcomes were not significantly different between asymptomatic and symptomatic participants.

CONCLUSIONS

The sleep quality of youth is adversely affected by concussion, particularly in females. Sleep quality appears to improve with time but may require more than 4 weeks to return to normal.

Abstract WP262: Three-dimensional Characterization Of Cerebral Microvasculature And Microhemorrhages

Introduction: Cerebral microhemorrhages (CMH) are the pathologic substrate of MRI-demonstrable cerebral microbleeds, and are thought to occur when integrity of cerebral microvessels is compromised, leading to deposits of hemosiderin/iron accumulating within brain tissue. The presence of CMH is associated with cognitive decline and ischemic and hemorrhagic stroke. Hypertension (HTN) is a major risk factor for cerebral microbleeds and has been linked to a more significant microbleed burden in patients. Despite the clinical significance of HTN and cerebral microbleeds, our understanding of HTN-induced microbleed formation remains limited, and the vascular origin of CMH remains obscure.

Methods: We used a perfusion-based vascular label with tissue clearing to enable three-dimensional visualization of CMH with the surrounding microvascular network. Adult (18-month-old) C57BL/6J mice were administered angiotensin II to induce HTN (n=10) or PBS (n=10). Lectin-DyLight-649 was injected retro-orbitally to bind to the endothelial walls of all blood vessels in a mouse. Brains were cut into 1-mm thick sections, stained with Prussian blue to label CMH, cleared using iDISCO, and imaged via confocal microscopy. MATLAB and neuTube were used to quantify vessel diameters.

Results: Using this methodology, we were able to collect three-dimensional transmission images of CMH that were colocalized with three-dimensional fluorescence images of the surrounding microvasculature. The average vessel diameter of the 5 nearest vessels to 17 different CMH was found to be 4.22±0.81 μm, which corresponds to capillary-size vessels.

Conclusions: These data support a capillary origin for cerebral microhemorrhages in this mouse model. The capillary origin implies a role for the blood-brain barrier in the development of CMH and cerebral microbleeds in this model of HTN and aging. Three-dimensional imaging has substantial utility for improved understanding of CMH origin.

Abstract TP127: Hypertension Provokes Development Of Cerebral Microhemorrhages In A Mouse Model

Introduction: Cerebral microhemorrhages (CMH) are the pathological substrate for cerebral microbleeds, represent focal hemosiderin deposits on MRI, and are associated with increased risk of cognitive impairment and ischemic and hemorrhagic stroke. Aging and hypertension are the most common risk factors for cerebral microbleeds. In this study, we analyzed the effect of hypertension on the development of CMH in a mouse model of aging.

Methods: Hypertension was induced in aged (17 months old) female and male C57BL/6J mice, via infusion of angiotensin II (ATII) at 1000 ng/kg/min via Alzet pump over four weeks. We further examined underlying mechanism by inhibiting ATII type 1 receptor (AT1R) with telmisartan, via drinking water for 4 weeks. We collected mouse brains and performed standard histology using Prussian blue staining to detect CMH formation at 20x magnification. We also examined correlations between CMH burden and systolic (SBP) and diastolic (DPB) blood pressures.

Results: ATII infusion induced significant increases in SBP (121±4 mmHg to 159±6 mmHg; p<0.001) and DBP (94±4 mmHg to 129±7 mmHg; p<0.001). Telmisartan completely blocked ATII-induced blood pressure elevation. Hypertension increased the number of CMH (p=0.01) in male and female mice. In animals with ATII infusion, number of CMH were positively correlated with SBP (r=0.45, p=0.02) and DBP (r=0.47, p=0.01). Telmisartan reduced by 55% the number of ATII-induced CMH, but compared to controls, CMH number remained elevated (p=0.03) in telmisartan-treated animals.

Conclusions: ATII-induced hypertension promotes the development of CMH in aged mice in a manner that appears dependent on the extent of hypertension. However, in the presence of ATII with ATIR blockade, CMH develops even in the absence of hypertension. These findings emphasize the importance of presence and extent of hypertension in development of CMH in aging, as well as the significance of non-AT1R-mediated pathways independent of hypertension in ATII-induced CMH.

Abstract 87: Chronic Kidney Disease Induces Cerebral Microhemorrhages In Aged Mice

Introduction: Chronic kidney disease (CKD) is increasingly recognized as a risk factor of cerebral microvascular disease, but its association with common neuropathologic changes is not well understood. We investigated the relationship between CKD and development of cerebral microhemorrhages (CMH) in a mouse model of aging. We also examined the effect of CKD on endothelial cell function in an in vitro blood-brain barrier (BBB) model.

Methods: CKD was produced in aged C57BL/6J mice using an adenine-induced tubulointerstitial nephritis model. We performed standard histology using Prussian blue staining to examine CMH formation. Correlations between CMH burden and serum creatinine levels were assessed. In cell culture studies, human brain microvascular endothelial cells (ihBMECs) derived from induced pluripotent stem cell line IMR90-4 were treated with serum from healthy or CKD patient donors for up to 3 days. Transendothelial electrical resistance (TEER) and tracer (sodium fluorescein) permeability across the ihBMEC monolayer were measured to assess the integrity of the in vitro BBB.

Results: CKD induction in aged C57BL/6J mice caused a significant increase in both serum creatinine level (0.09±0.01 mg/dL to 0.43±0.03 mg/dL, p<0.001) and CMH number (p<0.05), without alteration of systolic or diastolic blood pressure. Number of CMH was positively correlated with serum creatinine level (r=0.41, p<0.001). Incubation of CKD serum with ihBMECs significantly reduced TEER by 26% (p<0.05) and increased sodium fluorescein permeability by 100% (p<0.01) across the ihBMEC monolayer.

Conclusions: Adenine-induced CKD promotes the development of CMH in aged C57BL/6J mice independent of blood pressure, and extent of CMH development is directly proportional to degree of renal insufficiency. Moreover, serum-derived factors in CKD disrupt BBB integrity in vitro. These findings suggest CKD provokes microvascular injury at the capillary level, leading to CMH formation in this model.

644. Phenotypic and Genomic Analysis of Novel, Fastidious, Gram-negative Bacilli Isolated from Clinical Wound Specimens

Background

Animal bites are considered the thirteenth leading cause of nonfatal ED visits. Epidemiology studies have shown a rise in dog bites during the COVID-19 pandemic in the U.S. In Oct. 2020, we received a facultatively anaerobic, non-hemolytic Gram-negative rod (OL1) from a dog bite wound for identification. 16S rRNA gene sequencing showed OL1 was 95.9% identical to Ottowia pentelensis in the family Comamonadaceae. Our historical sequence database revealed 8 additional isolates (OL2-OL9) from hand wounds/abscesses (including 3 dog bites) since 2012 that had ⩾ 99.8% identity with OL1. Most other Ottowia sp. have been isolated from industrial and food sources, with no reports from patient samples. As these clinical isolates likely represent a novel Ottowia species, we aimed to characterize them using both phenotypic and genomic approaches.

Methods

The OL isolates were tested in API 20 NE panels (8 conventional and 12 assimilation tests) for 4 d. Paired-end genomic DNA libraries (Nextera DNA Flex Library Prep, Illumina) were sequenced as 150 nt reads by Illumina NovaSeq. De novo assembly, annotation, functional prediction, and phylogenetic analyses were performed with Geneious, PATRIC, and web-prediction databases. Strain comparison was done with StrainTypeMer.

Results

All 9 OL isolates were negative for indole, urea, arginine, esculin, PNPG, glucose fermentation and carbohydrate assimilation tests. Potassium gluconate assimilation and gelatin hydrolysis were positive for 5 and 4 isolates, respectively. StrainTypeMer showed the isolates from different patients were not closely related, but 2 from the same patient were indistinguishable. The estimated genome size was ~3.1 Mbp, with 66.1% G/C, and ~3523 coding genes. Potential virulence factors (BrkB and MviM), multidrug efflux systems (MdtABC-TolC and Bcr/CflA), and 1-2 intact prophages were identified. Genomic phylogenetic analysis with RAxML showed the OL isolates clustered separately from all known Ottowia spp.

Conclusion

These OL isolates are fastidious, Gram-negative bacilli from clinical wound specimens, and are associated with dog bites. Genomic and 16S rRNA gene sequence analysis suggests these isolates constitute a novel species within the family Comamonadaceae.

Disclosures

All Authors: No reported disclosures

Guiding principles for rewilding

There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations' rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding.

Prevalence of cerebral small vessel disease in a Fabry disease cohort

Objective

To characterize the prevalence of brain ischemia and cerebral small vessel disease in a cohort of patients with Fabry disease (FD) seen at an academic medical center.

Background

FD is an inherited X-linked lysosomal storage disorder with central nervous system involvement. Limited data are available in the literature on the cerebrovascular neuroimaging findings in FD, and the reported prevalence of stroke symptoms and cerebral small vessel disease has varied widely.

Design/methods

Brain MRI was performed in 21 patients with FD followed at University of California Irvine Medical Center. Stroke symptoms were assessed and quantification of cerebral microvascular disease was performed using small vessel disease (SVD) score. Lacunes and deep white matter hyperintensities were scored on a four-point scale of 0 (absent) and 1–3 to account for increasing severity; microbleeds were scored 0 (absent) or 1 (present). The total SVD score is the sum of the three components and ranges from 0 to 7.

Results

Nearly 43% (9/21) of our FD cohort (aged 32–81 years, mean = 50) had a SVD score of one or higher, all of whom were aged 50 or more years. The most common MRI-defined SVD was white matter hyperintensities (9/9, 100%), followed by microbleeds (6/9, 66%), and lacunes (3/9, 33%). The three patients with previous strokes had some of the highest SVD scores reported in the cohort (scores 3–5).

Conclusions

In this cohort, the prevalence of SVD (43%) was three times higher than prevalence of stroke symptoms. SVD score was highest in the those who had experienced a stroke. These findings emphasize the importance of routine MRI screening of patients with FD in order to identify and treat high risk patients.

Grow fast, die young: Does compensatory growth reduce survival of juvenile blacktip sharks (Carcharhinus limbatus) in the western Gulf of Mexico?

Effective conservation and management necessitate an understanding of the ecological mechanisms that shape species life histories in order to predict how variability in natural and anthropogenic impacts will alter growth rates, recruitment, and survival. Among these mechanisms, the interaction between parturition timing and prey availability frequently influences offspring success, particularly when postnatal care is absent. Here, we assess how parturition timing and nursery conditions, including prey abundance and environmental conditions, influence the growth and potential survival of blacktip sharks (Carcharhinus limbatus) in western Gulf of Mexico (GOM) estuaries over their first year. Catch data from long-term gillnet monitoring allowed for clear delineation of cohorts based on size frequency distribution plots, and showed that late parturition cohorts born in estuaries with fewer prey resources exhibited more rapid growth than early parturition cohorts that experienced more abundant prey. Compensatory behaviors that promoted accelerated growth led to reduced second year residency, likely due to reduced survival resultant from greater risk taking and potentially due to reduced site fidelity attributed to larger body size. Water temperatures influenced blacktip growth rates through physiological increases in metabolism and potential premigratory foraging cues associated with cooling temperatures. Gradual warming of the GOM (0.03°C year-1) was also correlated with earlier parturition across the study period (1982-2017), similar to other migratory species. Considering current trends in climate and associated phenological shifts in many animals, testing hypotheses assessing compensatory growth-risk trade-offs is important moving forward to predict changes in life histories and associated recruitment in concert with current and future conservation actions, like wildlife management.

Kidney Function Is Not Related to Brain Amyloid Burden on PET Imaging in The 90+ Study Cohort

Cognitive decline is common in chronic kidney disease (CKD). While the evidence of vascular cognitive impairment in this population is robust, the role of Alzheimer's pathology is unknown. We evaluated serum cystatin C-estimated glomerular filtration rate (eGFR), brain amyloid-β positron emission tomography (PET) imaging, and cognitive function in 166 participants from The 90+ Study. Mean age was 93 years (range 90-107) and 101 (61%) were women; 107 participants had normal cognitive status while 59 participants had cognitive impairment no dementia (CIND) or dementia. Mean ± standard deviation cystatin C was 1.59 ± 0.54 mg/L with eGFR 40.7 ± 18.7 ml/min/1.73m². Higher amyloid-β burden was associated with dementia, but not with age, diabetes, hypertension, or cardiovascular disease. We found no association between brain amyloid-β burden and cystatin C eGFR. We previously reported that kidney function was associated with cognition and cerebral microbleeds in the same cohort of oldest-old adults (90+ years old). Collectively, these findings suggest that microvascular rather than Alzheimer's pathology drives CKD-associated cognitive dysfunction in this population.

Management of gout in chronic kidney disease: a G-CAN Consensus Statement on the research priorities

Gout and chronic kidney disease (CKD) frequently coexist, but quality evidence to guide gout management in people with CKD is lacking. Use of urate-lowering therapy (ULT) in the context of advanced CKD varies greatly, and professional bodies have issued conflicting recommendations regarding the treatment of gout in people with concomitant CKD. As a result, confusion exists among medical professionals about the appropriate management of people with gout and CKD. This Consensus Statement from the Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) discusses the evidence and/or lack thereof for the management of gout in people with CKD and identifies key areas for research to address the challenges faced in the management of gout and CKD. These discussions, which address areas for research both in general as well as related to specific medications used to treat gout flares or as ULT, are supported by separately published G-CAN systematic literature reviews. This Consensus Statement is not intended as a guideline for the management of gout in CKD; rather, it analyses the available literature on the safety and efficacy of drugs used in gout management to identify important gaps in knowledge and associated areas for research.

Kwasowy komunizm. Nieukończone wprowadzenie

Artykuł stanowi nieukończone przez autora wprowadzenie do książki, którą zmarły filozof Mark Fisher projektował pod koniec życia i której nigdy nie napisał. Przedstawia w nim zarys koncepcji kwasowego komunizmu, czyli myślowej prowokacji wskazującej na potrzebę przemyślenia dziedzictwa kultury radykalnych ruchów lat 60. i 70., zwłaszcza istniejącego w nich napięcia między indywidualizmem a kolektywizmem. Istotną inspiracją myśli Fishera pozostają zwłaszcza prace Herberta Marcusego.

Spectroscopic and deep learning-based approaches to identify and quantify cerebral microhemorrhages

Cerebral microhemorrhages (CMHs) are associated with cerebrovascular disease, cognitive impairment, and normal aging. One method to study CMHs is to analyze histological sections (5-40 μm) stained with Prussian blue. Currently, users manually and subjectively identify and quantify Prussian blue-stained regions of interest, which is prone to inter-individual variability and can lead to significant delays in data analysis. To improve this labor-intensive process, we developed and compared three digital pathology approaches to identify and quantify CMHs from Prussian blue-stained brain sections: (1) ratiometric analysis of RGB pixel values, (2) phasor analysis of RGB images, and (3) deep learning using a mask region-based convolutional neural network. We applied these approaches to a preclinical mouse model of inflammation-induced CMHs. One-hundred CMHs were imaged using a 20 × objective and RGB color camera. To determine the ground truth, four users independently annotated Prussian blue-labeled CMHs. The deep learning and ratiometric approaches performed better than the phasor analysis approach compared to the ground truth. The deep learning approach had the most precision of the three methods. The ratiometric approach has the most versatility and maintained accuracy, albeit with less precision. Our data suggest that implementing these methods to analyze CMH images can drastically increase the processing speed while maintaining precision and accuracy.

A Systematic Approach to Comparing Thermal Activity of the Thoracic Region and Saddle Pressure Distribution beneath the Saddle in a Group of Non-Lame Sports Horses

Simple Summary

Thermography is a non-invasive method for measuring surface temperatures. Due to its ease of use, it may be a convenient way of identifying hypo/hyperthermic areas under a saddle that may be related to saddle pressures. A thermal camera quantified temperatures at specific locations (left/right) of the thoracic region at three-time points; a Pliance (Novel) pressure mat determined the mean/peak saddle pressures (kPa) during a period of exercise. Differences between saddle widths in the cranial/caudal mean and peak saddle pressures were found. The maximum thermal temperatures increased post lunge and post ridden compared to the baseline. No difference between post lunge and post ridden exercise were found. The thermal activity does not appear to be representative of increased saddle pressure values. The sole use of thermal imaging for saddle fitting should be applied with caution.

Abstract

Thermography is a non-invasive method for measuring surface temperatures and may be a convenient way of identifying hypo/hyperthermic areas under a saddle that may be related to saddle pressures. A thermal camera quantified minimum/maximum/mean temperatures at specific locations (left/right) of the thoracic region at three-time points: (1) baseline; (2) post lunging; (3) post ridden exercise in eight non-lame sports horses ridden by the same rider. A Pliance (Novel) pressure mat determined the mean/peak saddle pressures (kPa) in the cranial and caudal regions. General linear mixed models with the horse as the random factor investigated the time point (fixed factor: baseline; lunge; ridden) and saddle fit (fixed factor: correct; wide; narrow) on thermal parameters with Bonferroni post hoc comparison. The saddle pressure data (grouped: saddle width) were assessed with an ANOVA and Tukey post hoc comparison (p ≤ 0.05). Differences between the saddle widths in the cranial/caudal mean (p = 0.05) and peak saddle pressures (p = 0.01) were found. The maximum temperatures increased post lunge (p ≤ 0.0001) and post ridden (p ≤ 0.0001) compared to the baseline. No difference between post lunge and post ridden exercise (all p ≥ 0.51) was found. The thermal activity does not appear to be representative of increased saddle pressure values. The sole use of thermal imaging for saddle fitting should be applied with caution.

Stroke Preventability in Large Vessel Occlusion Treated With Mechanical Thrombectomy

Objective: The preventability of strokes treated by mechanical thrombectomy is unknown. The purpose of this study was to analyze stroke preventability for patients treated with mechanical thrombectomy for large vessel occlusion.

Methods: We conducted retrospective analyses of 300 patients (mean ± SE age 69 ± 0.9 years, range 18–97 years; 53% male) treated with mechanical thrombectomy for large vessel occlusion from January 2008 to March 2019. We collected data including demographics, NIH Stroke Scale (NIHSS) at onset, and (beginning in 2015) classified 90-day outcome by modified Rankin Scale (mRS). Patients were evaluated using a Stroke Preventability Score (SPS, 0 to 10 points) based on how well patients had been treated given their hypertension, hyperlipidemia, atrial fibrillation, and prior stroke history. We examined the relationship of SPS with NIHSS at stroke onset and with mRS outcome at 90 days.

Results: SPS was calculated for 272 of the 300 patients, with mean ± SE of 2.1 ± 0.1 (range 0–8); 89 (33%) had no preventability (score 0), 120 (44%) had low preventability (score 1–3), and 63 (23%) had high preventability (score 4 or higher). SPS was significantly correlated with age (r = 0.32, p < 0.0001), while NIHSS (n = 267) was significantly higher (p = 0.03) for patients with high stroke preventability vs. low/no preventability [18.8 ± 0.92 (n = 62) vs. 16.5 ± 0.51 (n = 205)]. Among 118 patients with mRS, outcome was significantly worse (p = 0.04) in patients with high stroke preventability vs. low/no preventability [4.7 ± 0.29 (n = 28) vs. 3.8 ± 0.21 (n = 90)]. The vast majority of patients with high stroke preventability had inadequately treated atrial fibrillation (85%, 53/62).

Conclusions: Nearly one quarter of stroke patients undergoing mechanical thrombectomy had highly preventable strokes. While stroke preventability showed some relationship to stroke severity at onset and outcome after treatment, preventability had the strongest association with age. These findings emphasize the need for improved stroke prevention in the elderly.

A comprehensive, contemporary assessment of the association between hepatosteatosis and coronary artery calcium scoring

Funding Acknowledgements

Type of funding sources: None.

onbehalf

Liverpool Multiparametric Imaging Collaboration

Background

Coronary artery calcium (CAC) score is a well-established technique for stratifying an individual’s cardiovascular disease (CVD) risk. Several well-established registries have incorporated CAC scoring into CVD risk prediction models to enhance accuracy. Hepatosteatosis (HS) has been shown to be an independent predictor of CVD events and can be measured on non-contrast computed tomography (CT). We sought to undertake a contemporary, comprehensive assessment of the influence of HS on CAC score alongside traditional CVD risk factors. In patients with HS it may be beneficial to offer routine CAC screening to evaluate CVD risk to enhance opportunities for earlier primary prevention strategies.

Methods

We performed a retrospective, observational analysis at a high-volume cardiac CT centre analysing consecutive CT coronary angiography (CTCA) studies. All patients referred for investigation of chest pain over a 28-month period (June 2014 to November 2016) were included. Patients with established CVD were excluded. The cardiac findings were reported by a cardiologist and retrospectively analysed by two independent radiologists for the presence of HS. Those with CAC of zero and those with CAC greater than zero were compared for demographic and cardiac risks. A multivariate analysis comparing the risk factors was performed to adjust for the presence of established risk factors. A binomial logistic regression model was developed to assess the association between the presence of HS and increasing strata of CAC.

Results

In total there were 1499 patients referred for CTCA without prior evidence of CVD. The assessment of HS was completed in 1195 (79.7%) and CAC score was performed in 1103 (92.3%). There were 466 with CVD and 637 without CVD. The prevalence of HS was significantly higher in those with CVD versus those without CVD on CTCA (51.3% versus 39.9%, p = 0.007). Male sex (50.7% versus 36.1% p= &lt;0.001), age (59.4 ± 13.7 versus 48.1 ± 13.6, p= &lt;0.001) and diabetes (12.4% versus 6.9%, p = 0.04) were also significantly higher in the CAC group compared to the CAC score of zero.

HS was associated with increasing strata of CAC score compared with CAC of zero (CAC score 1-100 OR1.47, p = 0.01, CAC score 101-400 OR:1.68, p = 0.02, CAC score &gt;400 OR 1.42, p = 0.14). This association became non-significant in the highest strata of CAC score.

Conclusion

We found a significant association between the increasing age, male sex, diabetes and HS with the presence of CAC. HS was also associated with a more severe phenotype of CVD based on the multinomial logistic regression model. Although the association reduced for the highest strata of CAC (CAC score &gt;400) this likely reflects the overall low numbers of patients within this group and is likely a type II error.

Based on these findings it may be appropriate to offer routine CVD risk stratification techniques in all those diagnosed with HS.

New insights into the trophic ecology of blacktip sharks (Carcharhinus limbatus) from a subtropical estuary in the western Gulf of Mexico

As environmental change persists, understanding resource use patterns is of value to predict the consequences of shifting trophic structures. While many sharks are opportunistic predators, some exhibit prey selectivity, putting them at higher risk compared to species with greater trophic plasticity. In the Gulf of Mexico (GOM), Clupeids and Sciaenids comprise 69% of blacktip shark (Carcharhinus limbatus) diets, which is consequential considering potential responses of these prey groups to disturbance and over harvesting. We assessed if blacktips exhibit selectivity for Clupeids and Sciaenids in the western GOM based on stomach contents from sharks in coastal Texas. Clupeids comprised <2% of diets, while striped mullet (Mugil cephalus) and red drum (Sciaenops ocellatus) comprised >70% of identifiable prey. Ontogenetic shifts from smaller (Clupeids, small Sciaenids) to larger, higher trophic level (Ariidae, Elasmobranchii) prey fits our understanding of foraging among coastal sharks, and suggests our regional understanding of blacktip trophic ecology may be limited by the sizes of sampled sharks. Observed increases in blacktip densities coupled with declines in prey (Mugilids, Sciaenids) is concerning if blacktips have limited diet plasticity. Yet GOM blacktips may be more generalized than previously thought, which is promising for conservation and management.

Efficacy and safety of urate-lowering therapy in people with kidney impairment: a GCAN-initiated literature review

OBJECTIVES

The aim was to evaluate the efficacy, defined as achieving target serum urate <6.0 mg/dl, and safety of urate-lowering therapies (ULTs) for people with gout and chronic kidney disease (CKD) stages 3-5.

METHODS

PubMed, The Cochrane Library and EMBASE were searched from 1 January 1959 to 31 January 2018 for studies that enrolled people with gout, who had an estimated glomerular filtration rate (eGFR) or creatinine clearance (CrCl) of <60 ml/min and exposure to allopurinol, febuxostat, probenecid, benzbromarone, lesinurad or pegloticase. All study designs other than case reports were included, except for people on dialysis, for whom we did include case reports.

RESULTS

There were 36 reports with an analysis of efficacy and/or safety based upon renal function: allopurinol (n = 12), febuxostat (n = 10), probenecid (n = 3), benzbromarone (n = 5), lesinurad (n = 5) and pegloticase (n = 1). There were 108 reports that involved people with gout and renal impairment but did not contain any analysis on efficacy and/or safety based upon renal function: allopurinol (n = 84), febuxostat (n = 14), benzbromarone (n = 1), lesinurad (n = 3) and pegloticase (n = 6). Most studies excluded people with more severe degrees of renal impairment (eGFR or CrCl of <30 ml/min). For allopurinol, in particular, there was significant variability in the dose of drug used and the efficacy in terms of urate lowering, across all levels of renal impairment.

CONCLUSION

There is a lack of evidence regarding the efficacy and/or safety of currently used ULTs according to different levels of renal function. Future studies should include patients with CKD and should report study outcomes stratified by renal function.

Mechanisms of Cerebral Microvascular Disease in Chronic Kidney Disease

Numerous studies report linkage between chronic kidney disease (CKD) and cerebrovascular disease. This association has been particularly strong for cerebral small vessel disease. Significant findings have emerged from studies ranging from case reports, small case series, and larger cohort investigations. The latter show a relationship between declining renal function, microvascular disease, and cognitive impairment. One troubling aspect has been the relative paucity of mechanistic investigations addressing the CKD-cerebrovascular disease linkage. Nevertheless, mechanistic observations have begun to emerge, showing cerebral microhemorrhage development in animal models of CKD independent of hypertension, an important co-morbidity in clinical studies. Initial cell culture studies show endothelial monolayer disruption by CKD serum, consistent with blood-brain barrier injury. It is noteworthy that CKD serum is known to contain multiple plausible mediators of microvascular injury. Further studies are on the horizon to address the critical question of potential linkage of renal dysfunction with vascular cognitive impairment.