Isolation of a Neurotoxin (a-colubritoxin) from a Nonvenomous Colubrid: Evidence for Early Origin of Venom in Snakes

Abstract. The evolution of venom in advanced snakes has been a focus of long-standing interest. Here we provide the first complete amino acid sequence of a colubrid toxin, which we have called a-colubritoxin, isolated from the Asian ratsnake Coelognathus radiatus (formerly known as Elaphe radiata), an archetypal nonvenomous snake as sold in pet stores. This potent postsynaptic neurotoxin displays readily reversible, competitive antagonism at the nicotinic receptor. The toxin is homologous with, and phylogenetically rooted within, the three-finger toxins, previously thought unique to elapids, suggesting that this toxin family was recruited into the chemical arsenal of advanced snakes early in their evolutionary history. LC-MS analysis of venoms from most other advanced snake lineages revealed the widespread presence of components of the same molecular weight class, suggesting the ubiquity of three-finger toxins across advanced snakes, with the exclusion of Viperidae. These results support the role of venom as a key evolutionary innovation in the early diversification of advanced snakes and provide evidence that forces a fundamental rethink of the very concept of nonvenomous snake

Endothelial C-type natriuretic peptide maintains vascular homeostasis

PMCID: PMC4151218Wellcome Trust (084449/Z/07/Z and 078496/Z/05/Z

Chronic disease IMPACT (chronic disease early detection and improved management in primary care project): an Australian stepped wedge cluster randomised trial

Background: Interrelated chronic vascular diseases (chronic kidney disease (CKD), type 2 diabetes (T2D) and cardiovascular disease (CVD)) are common with high morbidity and mortality. This study aimed to assess if an electronic-technology-based quality improvement intervention in primary care could improve detection and management of people with and at risk of these diseases. Methods: Stepped-wedge trial with practices randomised to commence intervention in one of five 16-week periods. Intervention included (1) electronic-technology tool extracting data from general practice electronic medical records and generating graphs and lists for audit; (2) education regarding chronic disease and the electronic-technology tool; (3) assistance with quality improvement audit plan development, benchmarking, monitoring and support. De-identified data analysis using R 3.5.1 conducted using Bayesian generalised linear mixed model with practice and time-specific random intercepts. Results: At baseline, eight included practices had 37,946 active patients (attending practice ≥3 times within 2 years) aged ≥18 years. Intervention was associated with increased OR (95% CI) for: kidney health checks (estimated glomerular filtration rate, urine albumin:creatinine ratio (uACR) and blood pressure) in those at risk 1.34 (1.26–1.42); coded diagnosis of CKD 1.18 (1.09–1.27); T2D diagnostic testing (fasting glucose or HbA1c) in those at risk 1.15 (1.08–1.23); uACR in patients with T2D 1.78 (1.56–2.05). Documented eye checks within recommended frequency in patients with T2D decreased 0.85 (0.77–0.96). There were no significant changes in other assessed variables. Conclusions: This electronic-technology-based intervention in primary care has potential to help translate guidelines into practice but requires further refining to achieve widespread improvements across the interrelated chronic vascular diseases

Using electronic medical record data to assess chronic kidney disease, type 2 diabetes and cardiovascular disease testing, recognition and management as documented in Australian general practice: a cross-sectional analysis

Objectives To evaluate the capacity of general practice (GP) electronic medical record (EMR) data to assess risk factor detection, disease diagnostic testing, diagnosis, monitoring and pharmacotherapy for the interrelated chronic vascular diseases-chronic kidney disease (CKD), type 2 diabetes (T2D) and cardiovascular disease. Design Cross-sectional analysis of data extracted on a single date for each practice between 12 April 2017 and 18 April 2017 incorporating data from any time on or before data extraction, using baseline data from the Chronic Disease early detection and Improved Management in PrimAry Care ProjecT. Deidentified data were extracted from GP EMRs using the Pen Computer Systems Clinical Audit Tool and descriptive statistics used to describe the study population. Setting Eight GPs in Victoria, Australia. Participants Patients were ≥18 years and attended GP ≥3 times within 24 months. 37 946 patients were included. Results Risk factor and disease testing/monitoring/treatment were assessed as per Australian guidelines (or US guidelines if none available), with guidelines simplified due to limitations in data availability where required. Risk factor assessment in those requiring it: 30% of patients had body mass index and 46% blood pressure within guideline recommended timeframes. Diagnostic testing in at-risk population: 17% had diagnostic testing as per recommendations for CKD and 37% for T2D. Possible undiagnosed disease: Pathology tests indicating possible disease with no diagnosis already coded were present in 6.7% for CKD, 1.6% for T2D and 0.33% familial hypercholesterolaemia. Overall prevalence: Coded diagnoses were recorded in 3.8% for CKD, 6.6% for T2D, 4.2% for ischaemic heart disease, 1% for heart failure, 1.7% for ischaemic stroke, 0.46% for peripheral vascular disease, 0.06% for familial hypercholesterolaemia and 2% for atrial fibrillation. Pharmaceutical prescriptions: the proportion of patients prescribed guideline-recommended medications ranged from 44% (beta blockers for patients with ischaemic heart disease) to 78% (antiplatelets or anticoagulants for patients with ischaemic stroke). Conclusions Using GP EMR data, this study identified recorded diagnoses of chronic vascular diseases generally similar to, or higher than, reported national prevalence. It suggested low levels of extractable documented risk factor assessments, diagnostic testing in those at risk and prescription of guideline-recommended pharmacotherapy for some conditions. These baseline data highlight the utility of GP EMR data for potential use in epidemiological studies and by individual practices to guide targeted quality improvement. It also highlighted some of the challenges of using GP EMR data

Conopressin-T from Conus tulipa reveals an antagonist switch in vasopressin-like peptide

We report the discovery of conopressing-T, a novel bioactive peptide isolated from Conus tulipa venom. Conopressin-T belongs to the vasopressin-like peptide family and displays high sequence homology to the mammalian hormone oxytocin (OT) and to vasotocin, the endogenerous vasopressin analogue found in the teleost fish, the cone snail's prey

Isolation and characterization of rufoxin, a novel protein exhibiting neurotoxicity from venom of the psammophiine, Rhamphiophis oxyrhynchus (Rufous beaked snake)

Colubrid snake venoms potentially represent a vast source of novel biological actives and structural motifs owing to their diverse phylogeny. The present study describes the identification of rufoxin, a neurotoxin from the venom of Rhamphiophis oxyrhynchus (Rufous beaked snake) which is a member of the African colubrid lineage, the psammophiines. Rufoxin (1 mu M) displayed reversible post-synaptic neurotoxic activity as evidenced by significant inhibition of indirect twitches and responses to exogenous nicotinic agonists in the chick biventer cervicis nerve-muscle preparation. Rufoxin (0.1-1.0 mu M) also caused a rightward parallel shift of cumulative concentration-response curves to carbachol (CCh; 0.6-80 mu M) without a significant depression of the maximum response, suggestive of classical competitive antagonism at the skeletal muscle nicotinic receptor. Rufoxin lacks NH2-terminal sequence homology to previously identified snake venom toxins. This work indicates a wider distribution of neurotoxins across the advanced snake superfamily than previously described. (c) 2006 Elsevier Ltd. All rights reserved

Chin-Dusting, “Nitroxyl: a vasodilator of human vessels that is not susceptible to tolerance

Abstract 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 pEC 50 : 6.5 + − 0.2; −log M) and saphenous veins (pEC 50 : 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 (K v channels) with 4-AP also significantly reduced responses to AS (pEC 50 : 5.5) and GTN, suggesting that the relaxation to both redox congeners is cGMP-and K v 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

Omega-Conotoxin GVIA mimetics based on an anthranilamide core: effect of variation in ammonium side chain lengths and incorporation of fluorine

A number of ω-conotoxin GVIA mimetics based on an anthranilamide core were prepared and tested for their affinity for rat brain Cav2.2 channels. Features such as the presence of hydroxyl and fluoro substituents on the tyrosine side chain mimic, the length of the chains on the lysine/arginine side chain mimics and the use of diguanidino and diamino substituents rather than mono-guanidine/mono-amine substitution were examined. The diguanidinylated compounds proved to be the most active and deletion of the hydroxyl substituent had a limited influence on activity. The SAR associated with variation in the lysine/arginine side chain mimics was not strong. The introduction of a fluoro substituent into the tyrosine mimic produced the most active compound prepared in this study (2g), with an EC50 at rat brain Cav2.2 channels of 6 μM

Raised soluble P-selectin moderately accelerates atherosclerotic plaque progression.

Soluble P-selectin (sP-selectin), a biomarker of inflammatory related pathologies including cardiovascular and peripheral vascular diseases, also has pro-atherosclerotic effects including the ability to increase leukocyte recruitment and modulate thrombotic responses in vivo. The current study explores its role in progressing atherosclerotic plaque disease. Apoe-/- mice placed on a high fat diet (HFD) were given daily injections of recombinant dimeric murine P-selectin (22.5 µg/kg/day) for 8 or 16 weeks. Saline or sE-selectin injections were used as negative controls. In order to assess the role of sP-selectin on atherothrombosis an experimental plaque remodelling murine model, with sm22α-hDTR Apoe-/- mice on a HFD in conjunction with delivery of diphtheria toxin to induce targeted vascular smooth muscle apoptosis, was used. These mice were similarly given daily injections of sP-selectin for 8 or 16 weeks. While plaque mass and aortic lipid content did not change with sP-selectin treatment in Apoe-/- or SM22α-hDTR Apoe-/- mice on HFD, increased plasma MCP-1 and a higher plaque CD45 content in Apoe-/- HFD mice was observed. As well, a significant shift towards a more unstable plaque phenotype in the SM22α-hDTR Apoe-/- HFD mice, with increased macrophage accumulation and lower collagen content, leading to a lower plaque stability index, was observed. These results demonstrate that chronically raised sP-selectin favours progression of an unstable atherosclerotic plaque phenotype