A novel interaction between the 5' untranslated region of the Chikungunya virus genome and Musashi RNA binding protein is essential for efficient virus genome replication.

Chikungunya virus (CHIKV) is a re-emerging, pathogenic alphavirus that is transmitted to humans by Aedesspp. mosquitoes-causing fever and debilitating joint pain, with frequent long-term health implications and high morbidity. The CHIKV replication cycle is poorly understood and specific antiviral therapeutics are lacking. In the current study, we identify host cell Musashi RNA binding protein-2 (MSI-2) as a proviral factor. MSI-2 depletion and small molecule inhibition assays demonstrated that MSI-2 is required for efficient CHIKV genome replication. Depletion of both MSI-2 and MSI-1 homologues was found to synergistically inhibit CHIKV replication, suggesting redundancy in their proviral function. Electromobility shift assay (EMSA) competition studies demonstrated that MSI-2 interacts specifically with an RNA binding motif within the 5' untranslated region (5'UTR) of CHIKV and reverse genetic analysis showed that mutation of the binding motif inhibited genome replication and blocked rescue of mutant virus. For the first time, this study identifies the proviral role of MSI RNA binding proteins in the replication of the CHIKV genome, providing important new insight into mechanisms controlling replication of this significant human pathogen and the potential of a novel therapeutic target.

NS5A domain I antagonises PKR to facilitate the assembly of infectious hepatitis C virus particles.

Hepatitis C virus NS5A is a multifunctional phosphoprotein comprised of three domains (DI, DII and DIII). DI and DII have been shown to function in genome replication, whereas DIII has a role in virus assembly. We previously demonstrated that DI in genotype 2a (JFH1) also plays a role in virus assembly, exemplified by the P145A mutant which blocked infectious virus production. Here we extend this analysis to identify two other conserved and surface exposed residues proximal to P145 (C142 and E191) that exhibited no defect in genome replication but impaired virus production. Further analysis revealed changes in the abundance of dsRNA, the size and distribution of lipid droplets (LD) and the co-localisation between NS5A and LDs in cells infected with these mutants, compared to wildtype. In parallel, to investigate the mechanism(s) underpinning this role of DI, we assessed the involvement of the interferon-induced double-stranded RNA-dependent protein kinase (PKR). In PKR-silenced cells, C142A and E191A exhibited levels of infectious virus production, LD size and co-localisation between NS5A and LD that were indistinguishable from wildtype. Co-immunoprecipitation and in vitro pulldown experiments confirmed that wildtype NS5A domain I (but not C142A or E191A) interacted with PKR. We further showed that the assembly phenotype of C142A and E191A was restored by ablation of interferon regulatory factor-1 (IRF1), a downstream effector of PKR. These data suggest a novel interaction between NS5A DI and PKR that functions to evade an antiviral pathway that blocks virus assembly through IRF1.

Thrombin cleavage of the hepatitis E virus polyprotein at multiple conserved locations is required for genome replication.

The genomes of positive-sense RNA viruses encode polyproteins that are essential for mediating viral replication. These viral polyproteins must undergo proteolysis (also termed polyprotein processing) to generate functional protein units. This proteolysis can be performed by virally-encoded proteases as well as host cellular proteases, and is generally believed to be a key step in regulating viral replication. Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis. The positive-sense RNA genome is translated to generate a polyprotein, termed pORF1, which is necessary and sufficient for viral genome replication. However, the mechanism of polyprotein processing in HEV remains to be determined. In this study, we aimed to understand processing of this polyprotein and its role in viral replication using a combination of in vitro translation experiments and HEV sub-genomic replicons. Our data suggest no evidence for a virally-encoded protease or auto-proteolytic activity, as in vitro translation predominantly generates unprocessed viral polyprotein precursors. However, seven cleavage sites within the polyprotein (suggested by bioinformatic analysis) are susceptible to the host cellular protease, thrombin. Using two sub-genomic replicon systems, we demonstrate that mutagenesis of these sites prevents replication, as does pharmacological inhibition of serine proteases including thrombin. Overall, our data supports a model where HEV uses host proteases to support replication and could have evolved to be independent of a virally-encoded protease for polyprotein processing.

Novel Bidentate Amine Ligand and the Interplay between Pd(II) and Pt(II) Coordination and Biological Activity.

Pt(II) and Pd(II) coordinating N-donor ligands have been extensively studied as anticancer agents after the success of cisplatin. In this work, a novel bidentate N-donor ligand, the N-[[4-(phenylmethoxy)phenyl]methyl]-2-pyridinemethanamine, was designed to explore the antiparasitic, antiviral and antitumor activity of its Pt(II) and Pd(II) complexes. Chemical and spectroscopic characterization confirm the formation of [MLCl2 ] complexes, where M=Pt(II) and Pd(II). Single crystal X-ray diffraction confirmed a square-planar geometry for the Pd(II) complex. Spectroscopic characterization of the Pt(II) complex suggests a similar structure. 1 H NMR, 195 Pt NMR and HR-ESI-MS(+) analysis of DMSO solution of complexes indicated that both compounds exchange the chloride trans to the pyridine for a solvent molecule with different reaction rates. The ligand and the two complexes were tested for in vitro antitumoral, antileishmanial, and antiviral activity. The Pt(II) complex resulted in a GI50 of 10.5 µM against the NCI/ADR-RES (multidrug-resistant ovarian carcinoma) cell line. The ligand and the Pd(II) complex showed good anti-SARS-CoV-2 activity with around 65 % reduction in viral replication at a concentration of 50 µM.

Positive strand RNA viruses differ in the constraints they place on the folding of their negative strand.

Genome replication of positive strand RNA viruses requires the production of a complementary negative strand RNA that serves as a template for synthesis of more positive strand progeny. Structural RNA elements are important for genome replication, but while they are readily observed in the positive strand, evidence of their existence in the negative strand is more limited. We hypothesized that this was due to viruses differing in their capacity to allow this latter RNA to adopt structural folds. To investigate this, ribozymes were introduced into the negative strand of different viral constructs; the expectation being that if RNA folding occurred, negative strand cleavage and suppression of replication would be seen. Indeed, this was what happened with hepatitis C virus (HCV) and feline calicivirus (FCV) constructs. However, little or no impact was observed for chikungunya virus (CHIKV), human rhinovirus (HRV), hepatitis E virus (HEV), and yellow fever virus (YFV) constructs. Reduced cleavage in the negative strand proved to be due to duplex formation with the positive strand. Interestingly, ribozyme-containing RNAs also remained intact when produced in vitro by the HCV polymerase, again due to duplex formation. Overall, our results show that there are important differences in the conformational constraints imposed on the folding of the negative strand between different positive strand RNA viruses.

Continuous glucose monitoring has an increasing role in pre-symptomatic type 1 diabetes: advantages, limitations, and comparisons with laboratory-based testing.

Type 1 diabetes (T1D) is well-recognised as a continuum heralded by the development of islet autoantibodies, progression to islet autoimmunity causing beta cell destruction, culminating in insulin deficiency and clinical disease. Abnormalities of glucose homeostasis are known to exist well before the onset of typical symptoms. Laboratory-based tests such as the oral glucose tolerance test (OGTT) and glycated haemoglobin (HbA1c) have been used to stage T1D and assess the risk of progression to clinical T1D. Continuous glucose monitoring (CGM) can detect early glycaemic abnormalities and can therefore be used to monitor for metabolic deterioration in pre-symptomatic, islet autoantibody positive, at-risk individuals. Early identification of these children can not only reduce the risk of presentation with diabetic ketoacidosis (DKA), but also determine eligibility for prevention trials, which aim to prevent or delay progression to clinical T1D. Here, we describe the current state with regard to the use of the OGTT, HbA1c, fructosamine and glycated albumin in pre-symptomatic T1D. Using illustrative cases, we present our clinical experience with the use of CGM, and advocate for an increased role of this diabetes technology, for monitoring metabolic deterioration and disease progression in children with pre-symptomatic T1D.

Identifying risk factors for developing obesity: a record linkage longitudinal study in metropolitan Sydney using the 45 and Up Study.

BACKGROUND: Primary care clinicians have key responsibilities in obesity prevention and weight management. AIMS: We aimed to identify risk factors for developing obesity among people aged ≥45 years. METHODS: We conducted a record linkage longitudinal study of residents of metropolitan Sydney, Australia using data from the: (1) 45 and Up Study at baseline (2005-2009) and first follow-up (2012-2015); (2) Medicare claims; (3) Pharmaceutical Benefits Scheme; and (4) deaths registry. We examined risk factors for developing obesity (body mass index [BMI]: 30-40) at follow-up, separately for people within the: (1) healthy weight range (BMI 18.5-<25) and (2) overweight range (BMI 25-<30) at baseline. Covariates included demographics, modifiable behaviours, health status, allied health use, and medication use. Crude and adjusted relative risks were estimated using Poisson regression modelling. RESULTS: At follow-up, 1.1% (180/16,205) of those in the healthy weight range group, and 12.7% (1,939/15,266) of those in the overweight range group developed obesity. In both groups, the following were associated with developing obesity: current smoking at baseline, physical functioning limitations, and allied health service use through team care planning, while any alcohol consumption and adequate physical activity were found to be associated with a lower risk of developing obesity. In the healthy weight group, high psychological distress and the use of antiepileptics were associated with developing obesity. In the overweight group, female sex and full-time work were associated with developing obesity, while older age was found to be associated with a lower risk of developing obesity. CONCLUSIONS: These findings may inform the targeting of preventive interventions for obesity in clinical practice and broader public health programs.

Early intervention to prevent weight gain requires a targeted multidisciplinary team-based approach to improve diet, increase physical activity, and change behaviour. However, the capacity to provide this within primary care is limited and there is little funding for consultations with allied health professionals. There is a need to identify priority at-risk groups to help primary care clinicians target interventions to those in most need. We have identified, using a longitudinal study of residents of metropolitan Sydney, key characteristics of older adults who are at risk of gaining weight and developing obesity, including risk behaviours (smoking and physical inactivity), and chronic conditions or their treatment (physical function, psychological distress, and use of anti-epileptic medications). These findings may help alert clinicians to the need for preventive interventions in selected cases, as well as informing the targeting of public health programs.

Responding to health literacy of refugees in Australian primary health care settings: a qualitative study of barriers and potential solutions.

BACKGROUND: Organisational health literacy is a promising area of research that enables a focus on how systems and services can be designed in ways that are responsive to populations with varying states and levels of health literacy, knowledge, and practices, including African refugees. The challenge is how organisations and professionals do this in practice, and research in this area is in its early stages. This qualitative study examined barriers to implementing health literacy responsive care practices in primary health care settings in Australia. It also offered suggestions to potentially address the barriers to improving organisational health literacy. METHODS: Refugees (n = 19), primary health care professionals (n = 14), and other key stakeholders (n = 19) were recruited through convenience and snowball strategies from three states in Australia: New South Wales, Victoria, and Queensland. All but one participant was interviewed face-to-face via Zoom. Semi-structured interview guides were used to guide the conversations. Transcriptions from audio recordings were analysed using directed content analysis. RESULTS: Thirteen themes were extracted from the data. Themes were organised into the following categories: structural and systemic, organisational context, individual professional level, individual patient level, and socio-community level. Major structural and system-level factors affecting organisational health literacy included rigid systems and structures and limited time. Key organisation-level factors included inflexible organisational processes and policies, institutionalised othering, discrimination and racism, and lack of interpreters. Individual professional factors were poor communication with patients and cultural knowledge gaps. Linguistic issues and service mistrust were key individual patient-level factors. Socio-community factors included limited community engagement. Participants identified potential solutions to help services navigate out of the barriers and improve their response to health literacy. CONCLUSION: The findings suggest that mainstream services and organisations could improve timely and appropriate health care access and utilisation for refugees through strategies such as designing services and health literacy programs with refugee communities, promoting health literacy champions in the workforce, integrating health literacy and culturally responsive care plans and strategies into organisational priorities.

Mutational analysis reveals a novel role for hepatitis C virus NS5A domain I in cyclophilin-dependent genome replication.

The hepatitis C virus (HCV) NS5A protein is comprised of three domains (D1-3). Previously, we observed that two alanine substitutions in D1 (V67A, P145A) abrogated replication of a genotype 2a isolate (JFH-1) sub-genomic replicon (SGR) in Huh7 cells, but this phenotype was partially restored in Huh7.5 cells. Here we demonstrate that five additional residues, surface-exposed and proximal to V67 or P145, exhibited the same phenotype. In contrast, the analogous mutants in a genotype 3a isolate (DBN3a) SGR exhibited different phenotypes in each cell line, consistent with fundamental differences in the functions of genotypes 2 and 3 NS5A. The difference between Huh7 and Huh7.5 cells was reminiscent of the observation that cyclophilin inhibitors are more potent against HCV replication in the former and suggested a role for D1 in cyclophilin dependence. Consistent with this, all JFH-1 and DBN3a mutants exhibited increased sensitivity to cyclosporin A treatment compared to wild-type. Silencing of cyclophilin A (CypA) in Huh7 cells inhibited replication of both JFH-1 and DBN3a. However, in Huh7.5 cells CypA silencing did not inhibit JFH-1 wild-type, but abrogated replication of all the JFH-1 mutants, and both DBN3a wild-type and all mutants. CypB silencing in Huh7 cells had no effect on DBN3a, but abrogated replication of JFH-1. CypB silencing in Huh7.5 cells had no effect on either SGR. Lastly, we confirmed that JFH-1 NS5A D1 interacted with CypA in vitro. These data demonstrate both a direct involvement of NS5A D1 in cyclophilin-dependent genome replication and functional differences between genotype 2 and 3 NS5A.

A structural and functional analysis of opal stop codon translational readthrough during Chikungunya virus replication.

Chikungunya virus (CHIKV) is an alphavirus, transmitted by Aedes species mosquitoes. The CHIKV single-stranded positive-sense RNA genome contains two open reading frames, coding for the non-structural (nsP) and structural proteins of the virus. The non-structural polyprotein precursor is proteolytically cleaved to generate nsP1-4. Intriguingly, most isolates of CHIKV (and other alphaviruses) possess an opal stop codon close to the 3' end of the nsP3 coding sequence and translational readthrough is necessary to produce full-length nsP3 and the nsP4 RNA polymerase. Here we investigate the role of this stop codon by replacing the arginine codon with each of the three stop codons in the context of both a subgenomic replicon and infectious CHIKV. Both opal and amber stop codons were tolerated in mammalian cells, but the ochre was not. In mosquito cells all three stop codons were tolerated. Using SHAPE analysis we interrogated the structure of a putative stem loop 3' of the stop codon and used mutagenesis to probe the importance of a short base-paired region at the base of this structure. Our data reveal that this stem is not required for stop codon translational readthrough, and we conclude that other factors must facilitate this process to permit productive CHIKV replication.

The hepatitis E virus ORF1 hypervariable region confers partial cyclophilin dependency.

Hepatitis E virus (HEV) is an emerging pathogen responsible for more than 20 million cases of acute hepatitis globally per annum. Healthy individuals typically have a self-limiting infection, but mortality rates in some populations such as pregnant women can reach 30 %. A detailed understanding of the virus lifecycle is lacking, mainly due to limitations in experimental systems. In this regard, the cyclophilins are an important family of proteins that have peptidyl-prolyl isomerase activity and play roles in the replication of a number of positive-sense RNA viruses, including hepatotropic viruses such as hepatitis C virus (HCV). Cyclophilins A and B (CypA/B) are the two most abundant Cyps in hepatocytes and are therefore potential targets for pan-viral therapeutics. Here, we investigated the importance of CypA and CypB for HEV genome replication using sub-genomic replicons. Using a combination of pharmacological inhibition by cyclosporine A (CsA), and silencing by small hairpin RNA we find that CypA and CypB are not essential for HEV replication. However, we find that silencing of CypB reduces replication of some HEV isolates in some cells. Furthermore, sensitivity to Cyp silencing appears to be partly conferred by the sequence within the hypervariable region of the viral polyprotein. These data suggest HEV is atypical in its requirements for cyclophilin for viral genome replication and that this phenomenon could be genotype- and sequence-specific.

ASPP2 binds to hepatitis C virus NS5A protein via an SH3 domain/PxxP motif-mediated interaction and potentiates infection.

Hepatitis C virus (HCV) infects millions of people worldwide and is a leading cause of liver disease. Despite recent advances in antiviral therapies, viral resistance can limit drug efficacy and understanding the mechanisms that confer viral escape is important. We employ an unbiased interactome analysis to discover host binding partners of the HCV non-structural protein 5A (NS5A), a key player in viral replication and assembly. We identify ASPP2, apoptosis-stimulating protein of p53, as a new host co-factor that binds NS5A via its SH3 domain. Importantly, silencing ASPP2 reduces viral replication and spread. Our study uncovers a previously unknown role for ASPP2 to potentiate HCV RNA replication.

Identification of Host Factors Differentially Induced by Clinically Diverse Strains of Tick-Borne Encephalitis Virus.

Tick-borne encephalitis virus (TBEV) is an important human arthropod-borne virus that causes tick-borne encephalitis (TBE) in humans. TBEV acutely infects the central nervous system (CNS), leading to neurological symptoms of various severity. No therapeutics are currently available for TBEV-associated disease. Virus strains of various pathogenicity have been described, although the basis of their diverse clinical outcome remains undefined. Work with infectious TBEV requires high-level biocontainment, meaning model systems that can recapitulate the virus life cycle are highly sought. Here, we report the generation of a self-replicating, noninfectious TBEV replicon used to study properties of high (Hypr) and low (Vs) pathogenic TBEV isolates. Using a Spinach2 RNA aptamer and luciferase reporter system, we perform the first direct comparison of Hypr and Vs in cell culture. Infectious wild-type (WT) viruses and chimeras of the nonstructural proteins 3 (NS3) and 5 (NS5) were investigated in parallel to validate the replicon data. We show that Hypr replicates to higher levels than Vs in mammalian cells, but not in arthropod cells, and that the basis of these differences map to the NS5 region, encoding the methyltransferase and RNA polymerase. For both Hypr and Vs strains, NS5 and the viral genome localized to intracellular structures typical of positive-strand RNA viruses. Hypr was associated with significant activation of IRF-3, caspase-3, and caspase-8, while Vs activated Akt, affording protection against caspase-mediated apoptosis. Higher activation of stress-granule proteins TIAR and G3BPI were an additional early feature of Vs but not for Hypr. These findings highlight novel host cell responses driven by NS5 that may dictate the differential clinical characteristics of TBEV strains. This highlights the utility of the TBEV replicons for further virological characterization and antiviral drug screening. IMPORTANCE Tick-borne encephalitis virus (TBEV) is an emerging virus of the flavivirus family that is spread by ticks and causes neurological disease of various severity. No specific therapeutic treatments are available for TBE, and control in areas of endemicity is limited to vaccination. The pathology of TBEV ranges from mild to fatal, depending on the virus genotype. Characterization of TBEV isolates is challenging due to the requirement for high-containment facilities. Here, we described the construction of novel TBEV replicons that permit a molecular comparison of TBEV isolates of high and low pathogenicity.

Insights into the role of the cobalt(III)-thiosemicarbazone complex as a potential inhibitor of the Chikungunya virus nsP4.

Chikungunya virus (CHIKV) is the causative agent of chikungunya fever, a disease that can result in disability. Until now, there is no antiviral treatment against CHIKV, demonstrating that there is a need for development of new drugs. Studies have shown that thiosemicarbazones and their metal complexes possess biological activities, and their synthesis is simple, clean, versatile, and results in high yields. Here, we evaluated the mechanism of action (MOA) of a cobalt(III) thiosemicarbazone complex named [CoIII(L1)2]Cl based on its in vitro potent antiviral activity against CHIKV previously evaluated (80% of inhibition on replication). Furthermore, the complex has no toxicity in healthy cells, as confirmed by infecting BHK-21 cells with CHIKV-nanoluciferase in the presence of the compound, showing that [CoIII(L1)2]Cl inhibited CHIKV infection with the selective index of 3.26. [CoIII(L1)2]Cl presented a post-entry effect on viral replication, emphasized by the strong interaction of [CoIII(L1)2]Cl with CHIKV non-structural protein 4 (nsP4) in the microscale thermophoresis assay, suggesting a potential mode of action of this compound against CHIKV. Moreover, in silico analyses by molecular docking demonstrated potential interaction of [CoIII(L1)2]Cl with nsP4 through hydrogen bonds, hydrophobic and electrostatic interactions. The evaluation of ADME-Tox properties showed that [CoIII(L1)2]Cl presents appropriate lipophilicity, good human intestinal absorption, and has no toxicological effect as irritant, mutagenic, reproductive, and tumorigenic side effects.

The Effect of Protective Coil Embolization of Penile Anastomoses during Prostatic Artery Embolization on Erectile Function: A Propensity-Matched Analysis.

PURPOSE: To explore whether coil embolization of penile collateral arteries to prevent nontarget embolization during prostatic artery embolization (PAE) negatively affects erectile function. MATERIALS AND METHODS: Retrospective analysis was performed on a prospectively maintained multicenter PAE database on all patients with benign prostatic hyperplasia (January 2014 to July 2016). International Index of Erectile Function (IIEF-5) scores were collected at baseline and within 12 months after the procedure. A logistic regression and nearest neighbor propensity-matched analysis (matched for age, baseline IIEF-5 scores, and use of 5α-reductase inhibitors) and paired t test were used to evaluate for differential impact on IIEF-5 scores between the group of patients who underwent (unilateral) penile collateral coil embolization and a matched control group of patients who did not. RESULTS: Of a total of 216 patients, 26 underwent coil protection of an accessory pudendal vessel/penile collateral. After exclusions, 22 propensity-matched pairs were identified. The mean IIEF-5 score at baseline for the coil-embolized group was 14.8 ± 8.3 (out of a possible score of 30) and that for the matched control group was 14.0 ± 7.8. At the 12-month follow-up after the procedure, the mean follow-up IIEF-5 score was 15.5 ± 8.0 for the coil-embolized group and 14.2 ± 8.2 for the matched control group. The change in IIEF-5 scores after PAE was not significantly different between the 2 groups (0.66 ± 3.8 vs 0.20 ± 2.0; P = .64; 95% CI, -1.53 to 2.44). CONCLUSIONS: When penile collateral arteries were identified, protective coil embolization of penile collateral/accessory pudendal vessels during PAE was unlikely to affect erectile function negatively.

Health literacy and cultural responsiveness of primary health care systems and services in Australia: reflections from service providers, stakeholders, and people from refugee backgrounds.

BACKGROUND: Primary health care [PHC] services with general practitioners (GPs) as the first point of access to health care services for people from refugee backgrounds in Australia can play a crucial role in building health literacy and promoting access to culturally appropriate services. To achieve equitable access and engagement, services and systems must be responsive to diverse health literacy and cultural needs. This study aims to explore how primary health services respond as a system and organisation to the health literacy and cultural needs of people from refugee backgrounds in Australia. METHODS: This exploratory qualitative study involved 52 semi-structured interviews among 19 Africans from refugee backgrounds, 14 service providers, including GPs and nurses, and 19 other stakeholders, such as service managers/directors. Participants resided in New South Wales, Victoria, and Queensland. Interviews were audio-recorded, transcribed, and coded into QSR NVivo 12. Data analysis was guided by reflexive thematic analysis. FINDINGS: Three interrelated themes were identified from the data relating to the health literacy and cultural responsiveness of PHC systems and services. The first theme, 'variable and ad hoc organisational response to health literacy and culturally responsive care,' demonstrated that some organisations did not systematically address the inherent complexity of navigating the health system nor the capacity of services and providers to respond to the cultural needs of people from refugee backgrounds. The second theme, 'individual provider responsibility,' captured the individual providers' interpersonal and relational efforts in supporting the health literacy and cultural needs of people from refugee backgrounds based on their motivation and adaptation. The third theme, 'refugee patient responsibility,' encapsulated people from refugee backgrounds' adaptations to and learning of the health system to navigate and access services. CONCLUSION: Health literacy and culturally responsive practices need to be systematised by PHC organisations to be implemented and sustained over time. There is a need for diversity in the organisational leadership and health care workforce, organisational commitment, health literacy and culturally responsive care policies, provider training, and auditing practice as essential components of the change process. Engaging with refugee communities would allow services to focus on people from refugee backgrounds' needs by design.

Derivation of oral cancer slope factors for hexavalent chromium informed by pharmacokinetic models and in vivo genotoxicity data.

Hexavalent chromium [Cr(VI)] is present in drinking water from natural and anthropogenic sources at approximately 1 ppb. Several regulatory bodies have recently developed threshold-based safety criteria for Cr(VI) of 30-100 ppb based on evidence that small intestine tumors in mice following exposure to ≥20,000 ppb are the result of a non-mutagenic mode of action (MOA). In contrast, U.S. EPA has recently concluded that Cr(VI) acts through a mutagenic MOA based, in part, on scoring numerous in vivo genotoxicity studies as having low confidence; and therefore derived a cancer slope factor (CSF) of 0.5 (mg/kg-day)-1, equivalent to ∼0.07 ppb. Herein, we demonstrate how physiologically based pharmacokinetic (PBPK) models and intestinal segment-specific tumor incidence data can form a robust dataset supporting derivation of alternative CSF values that equate to Cr(VI) concentrations ranging from below background to concentrations similar to those derived using threshold approaches-depending on benchmark response level and risk tolerance. Additionally, we highlight weaknesses in the rationale EPA used to discount critical in vivo genotoxicity studies. While the data support a non-genotoxic MOA, these alternative toxicity criteria require only PBPK models, robust tumor data, and fair interpretation of published in vivo genotoxicity data for Cr(VI).

Barriers and facilitators to the participation and engagement of primary care in shared-care arrangements with community mental health services for preventive care of people with serious mental illness: a scoping review.

BACKGROUND: People with serious mental illness die about 20 years earlier than the general population from preventable diseases. Shared-care arrangements between general practitioners and mental health services can improve consumers' access to preventive care, but implementing shared care is challenging. This scoping review sought to describe current evidence on the barriers and facilitators to the participation and engagement of primary care (specifically general practitioners) in shared-care arrangements with community mental health services for preventive health care of this population. METHODS: We searched Medline, Embase, CINAHL, Scopus, APA PsychINFO and EBM Reviews from 2010 to 2022. Data was extracted against a Microsoft Excel template developed for the review. Data was synthesised through tabulation and narrative methods. RESULTS: We identified 295 records. After eligibility screening and full-text review, seven studies were included. Facilitators of engagement included a good fit with organisation and practice and opportunities to increase collaboration, specific roles to promote communication and coordination and help patients to navigate appointments, multidisciplinary teams and teamwork, and access to shared medical/health records. Barriers included a lack of willingness and motivation on the part of providers and low levels of confidence with tasks, lack of physical structures to produce capacity, poor alignment of funding/incentives, inability to share patient information and challenges engaging people with severe mental illness in the service and with their care. CONCLUSION: Our results were consistent with other research on shared care and suggests that the broader literature is likely to be applicable to the context of general practitioner/mental health services shared care. Specific challenges relating to this cohort present difficulties for recruitment and retention in shared care programs. Sharing "goals and knowledge, mutual respect" and engaging in "frequent, timely, accurate, problem-solving communication", supported by structures such as shared information systems are likely to engage primary care in shared care arrangements more than the traditional focus on incentives, education, and guidelines.

Feasibility and acceptability of involving bilingual community navigators to improve access to health and social care services in general practice setting of Australia.

BACKGROUND: Patients from culturally and linguistically diverse (CALD) backgrounds often face difficulties in accessing health and social care services. This study explored the feasibility and acceptability of involving community health workers (CHWs) as bilingual community navigators (BCNs) in general practice setting, to help patients from CALD backgrounds access health and social care services in Australia. METHODS: This research was conducted in two general practices in Sydney where most patients are from specific CALD backgrounds (Chinese in one practice and Samoan in other). Three CHWs trained as BCNs were placed in these practices to help patients access health and social care service. A mixed-method design was followed to explore the feasibility and acceptability of this intervention including analysis of a record of services provided by BCNs and post-intervention qualitative interviews with patients, practice staff and BCNs exploring the feasibility and acceptability of the BCNs' role. The record was analyzed using descriptive statistics and interviews were audio-recorded, transcribed, and thematically analyzed. RESULTS: BCNs served a total of 95 patients, providing help with referral to other services (52.6%), information about appointments (46.3%), local resources (12.6%) or available social benefits (23.2%). Most patients received one service from BCNs with the average duration of appointments being half an hour. Overall, BCNs fitted in well within the practices and patients as well as staff of participating practices accepted them well. Their role was facilitated by patients' felt need for and acceptance of BCNs' services, recruitment of BCNs from the patient community, as well as BCNs' training and motivation for their role. Major barriers for patients to access BCNs' services included lack of awareness of the BCNs' roles among some patients and practice staff, unavailability of information about local culture specific services, and inadequate time and health system knowledge by BCNs. Limited funding support and the short timeframe of the project were major limitations of the project. CONCLUSION: BCNs' placement in general practice was feasible and acceptable to patients and staff in these practices. This first step needs to be followed by accredited training, development of the workforce and establishing systems for supervision in order to sustain the program. Future research is needed on the extension of the intrevention to other practices and culture groups.

Long-Term Persistence of Spike Protein Antibody and Predictive Modeling of Antibody Dynamics After Infection With Severe Acute Respiratory Syndrome Coronavirus 2.

BACKGROUND: Antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been shown to neutralize the virus in vitro and prevent disease in animal challenge models on reexposure. However, the current understanding of SARS-CoV-2 humoral dynamics and longevity is conflicting. METHODS: The COVID-19 Staff Testing of Antibody Responses Study (Co-Stars) prospectively enrolled 3679 healthcare workers to comprehensively characterize the kinetics of SARS-CoV-2 spike protein (S), receptor-binding domain, and nucleoprotein (N) antibodies in parallel. Participants screening seropositive had serial monthly serological testing for a maximum of 7 months with the Meso Scale Discovery Assay. Survival analysis determined the proportion of seroreversion, while 2 hierarchical gamma models predicted the upper and lower bounds of long-term antibody trajectory. RESULTS: A total of 1163 monthly samples were provided from 349 seropositive participants. At 200 days after symptoms, >95% of participants had detectable S antibodies, compared with 75% with detectable N antibodies. S antibody was predicted to remain detectable in 95% of participants until 465 days (95% confidence interval, 370-575 days) using a "continuous-decay" model and indefinitely using a "decay-to-plateau" model to account for antibody secretion by long-lived plasma cells. S-antibody titers were correlated strongly with surrogate neutralization in vitro (R2 = 0.72). N antibodies, however, decayed rapidly with a half-life of 60 days (95% confidence interval, 52-68 days). CONCLUSIONS: The Co-Stars data presented here provide evidence for long-term persistence of neutralizing S antibodies. This has important implications for the duration of functional immunity after SARS-CoV-2 infection. In contrast, the rapid decay of N antibodies must be considered in future seroprevalence studies and public health decision-making. This is the first study to establish a mathematical framework capable of predicting long-term humoral dynamics after SARS-CoV-2 infection. CLINICAL TRIALS REGISTRATION: NCT04380896.