Patterns of Antibody Response to Severe Acute Respiratory Syndrome Coronavirus 2 Among 1.6 Million Blood Donors: Impact of Vaccination, United States, December 2020-June 2021.

From December 2020 to June 2021, 1654487 blood donors were tested for antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S1 protein, and 1028547 (62.17%) were reactive. A rapid increase in prevalence was due to vaccination. Among a subset of 1567446 donors, 729771 (46.56%) reported SARS-CoV-2 vaccination, of whom 633769 (86.84%) were S1-antibody reactive only in response to vaccination and 68269 (9.35%) were reactive to both S1 and nucleocapsid in response to prior infection; the remainder were not reactive to either antibody. Among the 837675 (53.44%) donors who did not report vaccination, 210022 (25.07%) had reactivity to both antibodies and 29446 (3.52%) to S1 only.

Mitigating the risk of transfusion-transmitted infections with vector-borne agents solely by means of pathogen reduction.

BACKGROUND: This study evaluated whether pathogen reduction technology (PRT) in plasma and platelets using amotosalen/ultraviolet A light (A/UVA) or in red blood cells using amustaline/glutathione (S-303/GSH) may be used as the sole mitigation strategy preventing transfusion-transmitted West Nile (WNV), dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viral, and Babesia microti, Trypanosoma cruzi, and Plasmodium parasitic infections. METHODS: Antibody (Ab) status and pathogen loads (copies/mL) were obtained for donations from US blood donors testing nucleic acid (NAT)-positive for WNV, DENV, ZIKV, CHIKV, and B. microti. Infectivity titers derived from pathogen loads were compared to published PRT log10 reduction factors (LRF); LRFs were also reviewed for Plasmodium and T. cruzi. The potential positive impact on donor retention following removal of deferrals from required questioning and testing for WNV, Babesia, Plasmodium, and T. cruzi was estimated for American Red Cross (ARC) donors. RESULTS: A/UVA and S-303/GSH reduced infectivity to levels in accordance with those recognized by FDA as suitable to replace testing for all agents evaluated. If PRT replaced deferrals resulting from health history questions and/or NAT for WNV, Babesia, Plasmodium, and T. cruzi, 27,758 ARC donors could be retained allowing approximately 50,000 additional donations/year based on 1.79 donations/donor for calendar year 2019 (extrapolated to an estimated 125,000 additional donations nationally). CONCLUSION: Pathogen loads in donations from US blood donors demonstrated that robust PRT may provide an opportunity to replace deferrals associated with donor questioning and NAT for vector-borne agents allowing for significant donor retention and likely increased blood availability.

Investigational Testing for Zika Virus among U.S. Blood Donors.

BACKGROUND: Because of the potential severe clinical consequences of Zika virus (ZIKV) infection, the large numbers of asymptomatic travelers returning from ZIKV-active areas, the detection of ZIKV nucleic acid in blood, and reports of transmission of ZIKV through transfusion, in 2016 the Food and Drug Administration released recommendations for individual-unit nucleic acid testing to minimize the risk of transmission of ZIKV through blood transfusions. METHODS: The American Red Cross implemented investigational screening of donated blood for ZIKV RNA by means of transcription-mediated amplification (TMA). Confirmatory testing of reactive donations involved repeat TMA, TMA testing in exploratory minipools, real-time reverse-transcriptase polymerase chain reaction, IgM serologic testing, and red-cell TMA. Viral loads in plasma and red cells were estimated by means of end-point TMA. The costs of interdicting a donation that was confirmed to be positive were calculated for the 15-month period between June 2016 and September 2017. RESULTS: Of the 4,325,889 donations that were screened, 393,713 (9%) were initially tested in 24,611 minipools, and no reactive donations were found. Of the 3,932,176 donations that were subsequently tested individually, 160 were initially reactive and 9 were confirmed positive (a 1:480,654 confirmed-positive rate overall; positive predictive value, 5.6%; specificity, 99.997%). Six (67%) of the confirmed-positive donations were reactive on repeat TMA, of which 4 were IgM-negative; of these 4, all 3 that could be tested were reactive on minipool TMA. Two confirmed-positive donors had infections that had been transmitted locally (in Florida), 6 had traveled to ZIKV-active areas, and 1 had received an experimental ZIKV vaccine. ZIKV RNA levels in red cells ranged from 40 to 800,000 copies per milliliter and were detected up to 154 days after donation, as compared with 80 days of detection in plasma at levels of 12 to 20,000 copies per milliliter. On the basis of industry-reported costs of testing and the yield of the tests in our study, the cost of identifying 8 mosquito-borne ZIKV infections through individual-unit nucleic acid testing was $5.3 million per ZIKV RNA-positive donation. CONCLUSIONS: Screening of U.S. blood donations for ZIKV by individual-donation TMA was costly and had a low yield. Among the 9 confirmed ZIKV-positive donations, only 4 were IgM-negative; of these donations, all 3 that were tested were reactive on minipool TMA. (Funded by the American Red Cross and Grifols Diagnostic Solutions.).

Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

Despite its well-known antithrombotic properties, the effect of aspirin on blood pressure (BP) and hypertension pathology is unclear. The hugely varying doses used clinically have contributed to this confusion, with high-dose aspirin still commonly used due to concerns about the efficacy of low-dose aspirin. Because prostaglandins have been shown to both promote and inhibit T-cell activation, we also explored the immunomodulatory properties of aspirin in hypertension. Although the common preclinical high dose of 100 mg/kg/d improved vascular dysfunction and cardiac hypertrophy, this effect was accompanied by indices of elevated adaptive immunity, renal T-cell infiltration, renal fibrosis, and BP elevation in stroke-prone spontaneously hypertensive rats and in angiotensin II-induced hypertensive mice. The cardioprotective effects of aspirin were conserved with a lower dose (10 mg/kg/d) while circumventing heightened adaptive immunity and elevated BP. We also show that low-dose aspirin improves renal fibrosis. Differential inhibition of the COX-2 isoform may underlie the disparate effects of the 2 doses. Our results demonstrate the efficacy of low-dose aspirin in treating a vast array of cardiovascular parameters and suggest modulation of adaptive immunity as a novel mechanism underlying adverse cardiovascular profiles associated with COX-2 inhibitors. Clinical studies should identify the dose of aspirin that achieves maximal cardioprotection with a new awareness that higher doses of aspirin could trigger undesired autoimmunity in hypertensive individuals. This work also warrants an evaluation of high-dose aspirin and COX-2 inhibitor therapy in sufferers of inflammatory conditions who are already at increased risk for cardiovascular disease.-Khan, S. I., Shihata, W. A., Andrews, K. L., Lee, M. K. S., Moore, X.-L., Jefferis, A.-M., Vinh, A., Gaspari, T., Dragoljevic, D., Jennings, G. L., Murphy, A. J., Chin-Dusting, J. P. F. Effects of high- and low-dose aspirin on adaptive immunity and hypertension in the stroke-prone spontaneously hypertensive rat.

Qualification of the Geenius HIV 1/2 supplemental assay for use in the HIV blood donation screening algorithm.

BACKGROUND: A single, simplified approach for human immunodeficiency virus (HIV)-1/HIV-2 antibody confirmation/differentiation is needed for the HIV blood donation supplemental algorithm used in the United States. A clinical evaluation of the Geenius assay was performed-the same assay used for HIV diagnostic confirmation/differentiation in the United States since 2014. STUDY DESIGN AND METHODS: Well-characterized unlinked donation samples classified as HIV negative, false positive, or confirmed positive were included in the study: 200 antibody-nonreactive, 200 HIV-1 immunofluorescence assay (IFA) confirmed-positive, and 100 antibody-screen false-positive donations, equally divided between serum and plasma. Samples were retrieved from a repository, relabeled, and tested by an immunochromatographic test (Geenius HIV 1/2 Supplemental Assay, Bio-Rad). Comparator testing involved parallel US Food and Drug Administration (FDA)-licensed HIV-1 IFA or HIV-2 enzyme immunoassay (EIA) supplemental testing for any sample missing those results as part of routine testing (otherwise test-of-record results were used). Samples with discordant results were further tested with a rapid test (Multispot HIV-1/HIV-2 Rapid Test, Bio-Rad) to provide final sample interpretations. Testing volume reductions with the Geenius were estimated from screening performed by the American Red Cross from September 2016 to April 2019. RESULTS: Clinical results were 100% sensitivity and specificity with an indeterminate rate of 4.0% to 5.0%. From 2016 to 2019, sole use of the Geenius would reduce testing complexity for 5265 antibody repeat-reactive donations including 95.7% (5028) false positives, eliminating approximately 5000 unnecessary tests. CONCLUSION: Geenius FDA licensure (August 26, 2019) adding the HIV-1/HIV-2 differentiation/confirmation donation supplemental claim will enable replacement of previously used FDA-licensed supplemental assays while maintaining comparable sensitivity, avoiding thousands of unnecessary HIV-1-IFA, western blot, and HIV-2-EIA tests.

Beyond 'find and fix': improving quality and safety through resilient healthcare systems.

OBJECTIVE: The aim was to develop a method based on resilient healthcare principles to proactively identify system vulnerabilities and quality improvement interventions. DESIGN: Ethnographic methods to understand work as it is done in practice using concepts from resilient healthcare, the Concepts for Applying Resilience Engineering model and the four key activities that are proposed to underpin resilient performance-anticipating, monitoring, responding and learning. SETTING: Accident and Emergency Department (ED) and the Older People's Unit (OPU) of a large teaching hospital in central London. PARTICIPANTS: ED-observations 104 h, and 14 staff interviews. OPU-observations 60 h, and 15 staff interviews. RESULTS: Data were analysed to identify targets for quality improvement. In the OPU, discharge was a complex and variable process that was difficult to monitor. A system to integrate information and clearly show progress towards discharge was needed. In the ED, patient flow was identified as a complex high-intensity activity that was not supported by the existing data systems. The need for a system to integrate and display information about both patient and organizational factors was identified. In both settings, adaptive capacity was limited by the absence of systems to monitor the work environment. CONCLUSIONS: The study showed that using resilient healthcare principles to inform quality improvement was feasible and focused attention on challenges that had not been addressed by traditional quality improvement practices. Monitoring patient and workflow in both the ED and the OPU was identified as a priority for supporting staff to manage the complexity of the work.

Y-chromosome lineage determines cardiovascular organ T-cell infiltration in the stroke-prone spontaneously hypertensive rat.

The essential role of the Y chromosome in male sex determination has largely overshadowed the possibility that it may exert other biologic roles. Here, we show that Y-chromosome lineage is a strong determinant of perivascular and renal T-cell infiltration in the stroke-prone spontaneously hypertensive rat, which, in turn, may influence vascular function and blood pressure (BP). We also show, for the first time to our knowledge, that augmented perivascular T-cell levels can directly instigate vascular dysfunction, and that the production of reactive oxygen species that stimulate cyclo-oxygenase underlies this. We thus provide strong evidence for the consideration of Y-chromosome lineage in the diagnosis and treatment of male hypertension, and point to the modulation of cardiovascular organ T-cell infiltration as a possible mechanism that underpins Y- chromosome regulation of BP.-Khan, S. I., Andrews, K. L., Jackson, K. L., Memon, B., Jefferis, A.-M., Lee, M. K. S., Diep, H., Wei, Z., Drummond, G. R., Head, G. A., Jennings, G. L., Murphy, A. J., Vinh, A., Sampson, A. K., Chin-Dusting, J. P. F. Y-chromosome lineage determines cardiovascular organ T-cell infiltration in the stroke-prone spontaneously hypertensive rat.

Expanded feasibility of ferritin testing: stability of ferritin stored as whole blood and validation of plastic tubes.

BACKGROUND: Ferritin testing is a recommended strategy to mitigate iron depletion in blood donors. A barrier for some testing platforms is a requirement to complete sample management and testing within a temporal window incompatible with the logistics of many blood collectors. The ability to delay separation of plasma/serum from red cells and subsequent testing would enhance the feasibility of ferritin testing on a broader scale. STUDY DESIGN AND METHODS: Thirty blood donors provided a research donation of 12, 4-mL sample tubes of whole blood. Six pairs of serum and K2 -EDTA-plasma tubes were centrifuged and samples tested in triplicate on day of collection and on each of the next 5 days following storage at 4°C. Comparison of ferritin values for serum versus K2 -EDTA-plasma at baseline was performed to validate plastic EDTA-containing tubes. Variation of ferritin values during storage was assessed for direction and strength of any detectable changes. RESULTS: Ferritin values were comparable between EDTA-plasma and serum, with baseline values from EDTA-plasma samples 7% lower on average than serum (p < 0.0001 by paired t-test). Variability over five storage days was within approved parameters in the manufacturer's instructions. Within-run precision averaged 2% to 3% for each test day and within-subject precision across all samples averaged less than 5% for both serum and EDTA-plasma. Repeated measures showed no difference in changes during storage by tube type or day of testing. CONCLUSION: These results support flexible testing procedures, expanding the opportunity for blood centers to adopt this measure for assessing donor iron status.

Cyclo-Oxygenase (COX) Inhibitors and Cardiovascular Risk: Are Non-Steroidal Anti-Inflammatory Drugs Really Anti-Inflammatory?

Cyclo-oxygenase (COX) inhibitors are among the most commonly used drugs in the western world for their anti-inflammatory and analgesic effects. However, they are also well-known to increase the risk of coronary events. This area is of renewed significance given alarming new evidence suggesting this effect can occur even with acute usage. This contrasts with the well-established usage of aspirin as a mainstay for cardiovascular prophylaxis, as well as overwhelming evidence that COX inhibition induces vasodilation and is protective for vascular function. Here, we present an updated review of the preclinical and clinical literature regarding the cardiotoxicity of COX inhibitors. While studies to date have focussed on the role of COX in influencing renal and vascular function, we suggest an interaction between prostanoids and T cells may be a novel factor, mediating elevated cardiovascular disease risk with NSAID use.

Y Chromosome, Hypertension and Cardiovascular Disease: Is Inflammation the Answer?

It is now becomingly increasingly evident that the functions of the mammalian Y chromosome are not circumscribed to the induction of male sex. While animal studies have shown variations in the Y are strongly accountable for blood pressure (BP), this is yet to be confirmed in humans. We have recently shown modulation of adaptive immunity to be a significant mechanism underpinning Y-chromosome-dependent differences in BP in consomic strains. This is paralleled by studies in man showing Y chromosome haplogroup is a significant predictor for coronary artery disease through influencing pathways of immunity. Furthermore, recent studies in mice and humans have shown that Y chromosome lineage determines susceptibility to autoimmune disease. Here we review the evidence in animals and humans that Y chromosome lineage influences hypertension and cardiovascular disease risk, with a novel focus on pathways of immunity as a significant pathway involved.

Vascular dysfunction in the stroke-prone spontaneously hypertensive rat is dependent on constrictor prostanoid activity and Y chromosome lineage.

Vascular dysfunction is a hallmark of hypertension and the strongest risk factor to date for coronary artery disease. As Y chromosome lineage has emerged as one of the strongest genetic predictors of cardiovascular disease risk to date, we investigated if Y chromosome lineage modulated this important facet in the stroke-prone spontaneously hypertensive rat (SHRSP) using consomic strains. Here, we show that vascular dysfunction in the SHRSP is attributable to differential cyclooxygenase (COX) activity with nitric oxide (NO) levels playing a less significant role. Measurement of prostacyclin, the most abundant product of COX in the vasculature, confirmed the augmented COX activity in the SHRSP aorta. This was accompanied by functional impairment of the vasodilatory prostacyclin (IP) receptor, while inhibition of the thromboxane (TP) receptor significantly ameliorated vascular dysfunction in the SHRSP, suggesting this is the downstream target responsible for constrictor prostanoid activity. Importantly, Y chromosome lineage was shown to modulate vascular function in the SHRSP through influencing COX activity, prostacyclin levels and IP dysfunction. Vascular dysfunction in the renal and intrarenal arteries was also found to be prostanoid and Y chromosome dependent. Interestingly, despite no apparent differences in agonist-stimulated NO levels, basal NO levels were compromised in the SHRSP aorta, which was also Y chromosome dependent. Thus, in contrast with the widely held view that COX inhibition is deleterious for the vasculature due to inhibition of the vasodilator prostacyclin, we show that COX inhibition abolishes vascular dysfunction in three distinct vascular beds, with IP dysfunction likely being a key mechanism underlying this effect. We also delineate a novel role for Y chromosome lineage in regulating vascular function through modulation of COX and basal NO levels.

NFκB Inhibition Mitigates Serum Amyloid A-Induced Pro-Atherogenic Responses in Endothelial Cells and Leukocyte Adhesion and Adverse Changes to Endothelium Function in Isolated Aorta.

The acute phase protein serum amyloid A (SAA) is associated with endothelial dysfunction and early-stage atherogenesis. Stimulation of vascular cells with SAA increases gene expression of pro-inflammation cytokines and tissue factor (TF). Activation of the transcription factor, nuclear factor kappa-B (NFκB), may be central to SAA-mediated endothelial cell inflammation, dysfunction and pro-thrombotic responses, while targeting NFκB with a pharmacologic inhibitor, BAY11-7082, may mitigate SAA activity. Human carotid artery endothelial cells (HCtAEC) were pre-incubated (1.5 h) with 10 µM BAY11-7082 or vehicle (control) followed by SAA (10 µg/mL; 4.5 h). Under these conditions gene expression for TF and Tumor Necrosis Factor (TNF) increased in SAA-treated HCtAEC and pre-treatment with BAY11-7082 significantly (TNF) and marginally (TF) reduced mRNA expression. Intracellular TNF and interleukin 6 (IL-6) protein also increased in HCtAEC supplemented with SAA and this expression was inhibited by BAY11-7082. Supplemented BAY11-7082 also significantly decreased SAA-mediated leukocyte adhesion to apolipoprotein E-deficient mouse aorta in ex vivo vascular flow studies. In vascular function studies, isolated aortic rings pre-treated with BAY11-7082 prior to incubation with SAA showed improved endothelium-dependent vasorelaxation and increased vascular cyclic guanosine monophosphate (cGMP) content. Together these data suggest that inhibition of NFκB activation may protect endothelial function by inhibiting the pro-inflammatory and pro-thrombotic activities of SAA.

Nitroxyl (HNO) reduces endothelial and monocyte activation and promotes M2 macrophage polarization.

Nitroxyl anion (HNO) donors are currently being assessed for their therapeutic utility in several cardiovascular disorders including heart failure. Here, we examine their effect on factors that precede atherosclerosis including endothelial cell and monocyte activation, leucocyte adhesion to the endothelium and macrophage polarization. Similar to the NO donor glyceryl trinitrate (GTN), the HNO donors Angeli's salt (AS) and isopropylamine NONOate (IPA/NO) decreased leucocyte adhesion to activated human umbilical vein endothelial cells (HUVECs) and mouse isolated aorta. This reduction in adhesion was accompanied by a reduction in intercellular adhesion molecule-1 (ICAM-1) and the cytokines monocyte chemoattractant protein 1 (MCP-1) and interleukin 6 (IL-6) which was inhibitor of nuclear factor κB (NFκB) α (IκBα)- and subsequently NFκB-dependent. Intriguingly, the effects of AS on leucocyte adhesion, like those on vasodilation, were found to not be susceptible to pharmacological tolerance, unlike those observed with GTN. As well, HNO reduces monocyte activation and promotes polarization of M2 macrophages. Taken together, our data demonstrate that HNO donors can reduce factors that are associated with and which precede atherosclerosis and may thus be useful therapeutically. Furthermore, since the effects of the HNO donors were not subject to tolerance, this confers an additional advantage over NO donors.

Two human immunodeficiency virus Type 2 cases in US blood donors including serologic, molecular, and genomic characterization of an epidemiologically unusual case.

BACKGROUND: Blood donation screening for human immunodeficiency virus Type 2 (HIV-2) has been in place in the United States since 1992. However, only three HIV-2 antibody-positive donors have been reported to date, all detected via HIV-1 cross-reactivity. STUDY DESIGN AND METHODS: Here we identify two additional HIV-2-positive donors by routine anti-HIV-1 and anti-HIV-2 screening, including a first-time male donor living in Georgia having recently immigrated to the United States from West Africa (from a 1998 donation) and a Taiwanese female repeat donor (nurse) living in California with no travel outside of Taiwan or apparent connections to West Africa (from a 2015 donation). Neither donor acknowledged any risk factors, and both remained asymptomatic through follow-up. The second donor was further investigated by serologic, molecular, and genomic assays because of her unusual demographics. She was documented to harbor HIV-2 RNA, albeit sporadically by HIV-2-specific nucleic acid tests (35%-100% of replicates) and at very low levels (<9.6 IU/mL). Metagenomic next-generation sequencing (mNGS) confirmed the identification of a Group B HIV-2 strain, with recovered reads covering 46.9% of the predicted genome. CONCLUSIONS: The estimated frequency of an HIV-2-positive blood donor in the United States is one in 57 million donations. Due to the low frequency and low pathogenicity of HIV-2, public health and blood donation screening efforts must focus on HIV-1 detection and prevention. However, detection of HIV-2 infection in a donor with no apparent link to West Africa suggests that the United States must remain vigilant for HIV-2 virus infections. Ultradeep mNGS may be useful in the future for comprehensive identification of rare transfusion-transmissible agents.

Nitroxyl: a vasodilator of human vessels that is not susceptible to tolerance.

Pre-clinical studies have identified nitroxyl (HNO), the reduced congener of nitric oxide (NO•), as a potent vasodilator which is resistant to tolerance development. The present study explores the efficacy of HNO in human blood vessels and describes, for the first time, a vasodilator for humans that is not susceptible to tolerance. Human radial arteries and saphenous veins were obtained from patients undergoing coronary artery graft surgery and mounted in organ baths. Repeated vasodilator responses to the HNO donor Angeli's salt (AS) and NO• donor glyceryl trinitrate (GTN) were determined. AS- and GTN-induced concentration-dependent vasorelaxation of both human radial arteries (AS pEC50: 6.5 ± 0.2; -log M) and saphenous veins (pEC50: 6.7 ± 0.1) with similar potency. In human radial arteries, GTN-induced relaxation was reduced by the NO• scavenger hydroxocobalamin (HXC; P<0.05) but was unaffected by the HNO scavenger L-cysteine. Alternately, AS was unaffected by HXC but was reduced by L-cysteine (5-fold shift, P<0.05). The sGC (soluble guanylate cyclase) inhibitor ODQ abolished responses to both AS and GTN in arteries and veins (P<0.05). Inhibition of voltage-dependent potassium channels (Kv channels) with 4-AP also significantly reduced responses to AS (pEC50: 5.5) and GTN, suggesting that the relaxation to both redox congeners is cGMP- and Kv channel-dependent. Critically, a concentration-dependent development of tolerance to GTN (1 and 10 µM; P<0.05), but not to AS, was observed in both saphenous veins and radial arteries. Like GTN, the HNO donor AS causes vasorelaxation of human blood vessels via activation of a cGMP-dependent pathway. Unlike GTN, however, it does not develop tolerance in human blood vessels.

Augmented endothelial l-arginine transport ameliorates pressure-overload-induced cardiac hypertrophy.

NEW FINDINGS: What is the central question of this study? What is the potential role of endothelial NO production via overexpression of the l-arginine transporter, CAT1, as a mitigator of cardiac hypertrophy? What is the main finding and its importance? Augmentation of endothelium-specific l-arginine transport via CAT1 can attenuate pressure-overload-dependent cardiac hypertrophy and fibrosis. Our findings support the conclusion that interventions that improve endothelial l-arginine transport may provide therapeutic utility in the setting of myocardial hypertrophy. Such modifications may be introduced by exercise training or locally delivered gene therapy, but further experimental and clinical studies are required. Endothelial dysfunction has been postulated to play a central role in the development of cardiac hypertrophy, probably as a result of reduced NO bioavailability. We tested the hypothesis that increased endothelial NO production, mediated by increased l-arginine transport, could attenuate pressure-overload-induced cardiac hypertrophy. Echocardiography and blood pressure measurements were performed 15 weeks after transverse aortic constriction (TAC) in wild-type (WT) mice (n = 12) and in mice with endothelium-specific overexpression of the l-arginine transporter, CAT1 (CAT+; n = 12). Transverse aortic constriction induced greater increases in heart weight to body weight ratio in WT (by 47%) than CAT+ mice (by 25%) compared with the respective controls (P ≤ 0.05). Likewise, the increase in left ventricular wall thickness induced by TAC was significantly attenuated in CAT+ mice (P = 0.05). Cardiac collagen type I mRNA expression was greater in WT mice with TAC (by 22%; P = 0.03), but not in CAT+ mice with TAC, compared with the respective controls. Transverse aortic constriction also induced lesser increases in ß-myosin heavy chain mRNA expression in CAT+ mice compared with WT (P ≤ 0.05). Left ventricular systolic pressure after TAC was 36 and 39% greater in WT and CAT+ mice, respectively, compared with the respective controls (P ≤ 0.001). Transverse aortic constriction had little effect on left ventricular end-diastolic pressure in both genotypes. Taken together, these data indicate that augmenting endothelial function by overexpression of l-arginine transport can attenuate pressure-overload-induced cardiac hypertrophy.

Evaluating multisite multiprofessional simulation training for a hyperacute stroke service using the Behaviour Change Wheel.

BACKGROUND: Stroke is a clinical priority requiring early specialist assessment and treatment. A London (UK) stroke strategy was introduced in 2010, with Hyper Acute Stroke Units (HASUs) providing specialist and high dependency care. To support increased numbers of specialist staff, innovative multisite multiprofessional simulation training under a standard protocol-based curriculum took place across London. This paper reports on an independent evaluation of the HASU training programme. The main aim was to evaluate mechanisms for behaviour change within the training design and delivery, and impact upon learners including potential transferability to the clinical environment. METHODS: The evaluation utilised the Behaviour Change Wheel framework. Procedures included: mapping training via the framework; examination of course material; direct and video-recorded observations of courses; pre-post course survey sheet; and follow up in-depth interviews with candidates and faculty. RESULTS: Patient management skills and trainee confidence were reportedly increased post-course (post-course median 6 [IQ range 5-6.33]; pre-course median 5 [IQ range 4.67-5.83]; z = 6.42, P < .001). Thematic analysis showed that facilitated 'debrief' was the key agent in supporting both clinical and non-clinical skills. Follow up interviews in practice showed some sustained effects such as enthusiasm for role, and a focus on situational awareness, prioritization and verbalising thoughts. Challenges in standardising a multi-centre course included provision for local context/identity. CONCLUSIONS: Pan-London simulation training under the London Stroke Model had positive outcomes in terms of self-reported skills and motivation. These effects persisted to an extent in practice, where staff could recount applications of learning. The evaluation demonstrated that a multiple centre simulation programme congruent with clinical practice can provide valuable standard training opportunities that support patient care.

NADPH oxidase 1 plays a key role in diabetes mellitus-accelerated atherosclerosis.

BACKGROUND: In diabetes mellitus, vascular complications such as atherosclerosis are a major cause of death. The key underlying pathomechanisms are unclear. However, hyperglycemic oxidative stress derived from NADPH oxidase (Nox), the only known dedicated enzyme to generate reactive oxygen species appears to play a role. Here we identify the Nox1 isoform as playing a key and pharmacologically targetable role in the accelerated development of diabetic atherosclerosis. METHODS AND RESULTS: Human aortic endothelial cells exposed to hyperglycemic conditions showed increased expression of Nox1, oxidative stress, and proinflammatory markers in a Nox1-siRNA reversible manner. Similarly, the specific Nox inhibitor, GKT137831, prevented oxidative stress in response to hyperglycemia in human aortic endothelial cells. To examine these observations in vivo, we investigated the role of Nox1 on plaque development in apolipoprotein E-deficient mice 10 weeks after induction of diabetes mellitus. Deletion of Nox1, but not Nox4, had a profound antiatherosclerotic effect correlating with reduced reactive oxygen species formation, attenuation of chemokine expression, vascular adhesion of leukocytes, macrophage infiltration, and reduced expression of proinflammatory and profibrotic markers. Similarly, treatment of diabetic apolipoprotein E-deficient mice with GKT137831 attenuated atherosclerosis development. CONCLUSIONS: These studies identify a major pathological role for Nox1 and suggest that Nox1-dependent oxidative stress is a promising target for diabetic vasculopathies, including atherosclerosis.

Septic shock: desperately seeking treatment.

Septic shock results from the dysregulation of the innate immune response following infection. Despite major advances in fundamental and clinical research, patients diagnosed with septic shock still have a poor prognostic outcome, with a mortality rate of up to 50%. Indeed, the reasons leading to septic shock are still poorly understood. First postulated 30 years ago, the general view of septic shock as an acute and overwhelming inflammatory response still prevails today. Recently, the fact that numerous clinical trials have failed to demonstrate any positive medical outcomes has caused us to question our fundamental understanding of this condition. New and sophisticated technologies now allow us to accurately profile the various stages and contributory components of the inflammatory response defining septic shock, and many studies now report a more complex inflammatory response, particularly during the early phase of sepsis. In addition, novel experimental approaches, using more clinically relevant animal models, to standardize and stratify research outcomes are now being argued for. In the present review, we discuss the most recent findings in relation to our understanding of the underlying mechanisms involved in septic shock, and highlight the attempts made to improve animal experimental models. We also review recent studies reporting promising results with two vastly different therapeutic approaches influencing the renin-angiotensin system and applying mesenchymal stem cells for clinical intervention.

The value of screening signal-to-cutoff ratios for hepatitis C virus antibody confirmation.

A licensed recombinant immunoblot assay (RIBA) has been an integral component of the algorithm for confirmation of reactivity for antibody to hepatitis C virus in screening assays. This test may become unavailable in the future, so we have investigated the potential value of screening test signal values to support confirmation. Depending on the screening test used (Ortho enzyme-linked immunosorbent assay or Abbott PRISM chemiluminescent assay), signal-to-cutoff ratios of 5.00 and 3.20, respectively, were shown to have positive predictive values of 89.1 and 95%, with sensitivities of 93.1 and 88.7% relative to RIBA. However, additional steps will have to be added to assure equivalent performance to RIBA.