α-Conotoxin GIC from Conus geographus, a novel peptide antagonist of nicotinic acetylcholine receptors

Journal ArticleMany venomous organisms produce toxins that disrupt neuromuscular communication to paralyze their prey. One common class of such toxins comprises nicotinic acetylcholine receptor antagonists (nAChRs). Thus, most toxins that act on nAChRs are targeted to the neuromuscular subtype. The toxin characterized in this report, α-conotoxin GIC, is a most striking exception. The 16-amino acid peptide was identified from a genomic DNA clone from Conus geographus

Synthesis And Characterization Of125I-α-Conotoxin Arib[V11L;V16A] A Selective α7 Nicotinic Acetylcholine Receptor Antagonist

The α7 nicotinic acetylcholine receptors (nAChRs) are widely expressed both in the central nervous system (CNS) and periphery. In the CNS, 125I-α-bungarotoxin is commonly used to identify α7 nAChRs specifically. However, α-bungarotoxin also interacts potently with α1* and α9α10 nAChRs, two receptor subtypes in peripheral tissues that are colocalized with the α7 subtype. [ 3H]Methyllycaconitine is also frequently used as an α7-selective antagonist, but it has significant affinity for α6* and α9α10 nAChR subtypes. In this study, we have developed a highly α7-selective α-conotoxin radioligand by iodination of a naturally occurring histidine. Both mono- and diiodo derivatives were generated and purified (specific activities were 2200 and 4400 Ci mmol-1, respectively). The properties of the mono- and diiodo derivatives were very similar to each other, but the diiodo was less stable. For monoidodo peptide, saturation binding to mouse hippocampal membranes demonstrated a Kd value of 1.15 ± 0.13 nM, similar to that of 125I-α-bungarotoxin in the same preparations (0.52 ± 0.16 nM). Association and dissociation kinetics were relatively rapid (k obs for association at 1 nM was 0.027 ± 0.007 min -1; koff = 0.020 ± 0.001 min-1). Selectivity was confirmed with autoradiography using α7-null mutant tissue: specific binding was abolished in all regions of α7-/- brains, whereas wild-type mice expressed high levels of labeling and low nonspecific binding. 125I-α-conotoxin ArIB[V11L; V16A] should prove useful where α7 nAChRs are coexpressed with other subtypes that are also labeled by existing ligands. Furthermore, true equilibrium binding experiments could be performed on α7 nAChRs, something that is impossible with 125I-α-bungarotoxin. Copyright © 2008 by The American Society for Pharmacology and Experimental Therapeutics

BetaMe: impact of a comprehensive digital health programme on HbA1c and weight at 12 months for people with diabetes and pre-diabetes: study protocol for a randomised controlled trial

Abstract Background Long-term conditions (LTCs) are the biggest contributor to health loss in New Zealand. The economic cost and burden on the health system is substantial and growing. Self-management strategies offer a potential way to reduce the pressure on health services. This study evaluates a comprehensive self-management programme (the BetaMe programme) delivered by mobile and web-based technologies for people with Type 2 diabetes (T2DM) and pre-diabetes. The primary aim of this study is to evaluate the effectiveness of the BetaMe programme versus usual care among primary care populations in improving the control of T2DM and pre-diabetes, as measured by change in HbA1c and weight over 12 months. Methods Participants will be recruited through two primary healthcare organisations and a Māori healthcare provider in New Zealand (n = 430). Eligible participants will be 18 to 75 years old, with T2DM or pre-diabetes, with an HbA1c of 41–70 mmol/mol up to 2 years prior to study commencement. Eligible participants who consent to participate will be individually randomised to the control arm (usual care) or intervention arm (usual care and BetaMe). The programme consists of a 16-week core followed by a maintenance period of 36 weeks. It incorporates (1) individualised health coaching, (2) goal setting and tracking, (3) peer support in an online forum and (4) educational resources and behaviour-change tools. The primary outcome measures are change in HbA1c and weight at 12 months. Secondary outcomes are changes in waist circumference, blood pressure, patient activation and diabetes-specific behaviours. All outcomes will be assessed at 4 and 12 months for the total study population and for Māori and Pacific participants specifically. All primary analyses will be based on intention-to-treat. Primary analysis will use linear mixed models comparing mean outcome levels adjusted for initial baseline characteristics at 12 months. Discussion This is a randomised controlled trial of a comprehensive self-management intervention for people with diabetes and pre-diabetes. If effective, this programme would allow healthcare providers to deliver an intervention that is person-centred and supports the self-care of people with T2DM, pre-diabetes and potentially other LTCs. Trial registration Australian New Zealand Clinical Trials Registry, ID: ACTRN12617000549325. Registered on 19 April 2017

The risk of disease to great apes : Simulating disease spread in orang-utan (pongo pygmaeus wurmbii) and chimpanzee (pan troglodytes schweinfurthii) association networks

All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are particularly threatened by infectious disease outbreaks as a result of their social structure.Publisher PDFPeer reviewe

Additional file 3: of BetaMe: impact of a comprehensive digital health programme on HbA1c and weight at 12 months for people with diabetes and pre-diabetes: study protocol for a randomised controlled trial

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