Realtime physical simulator for virtual reality sailing by patients with spinal cord injury: an innovative voyage.

Background: The aim of this study was to explore whether sail training using a VSail® simulator would allow people with spinal cord injuries (SCI) to learn to sail in a safe controlled environment and then sail competently on the water in wind of moderate strength (12 knots). A battery of physical tests and questionnaires was used to evaluate possible improvements in health and well-being as a consequence of participation in the trial. Methods: Twenty participants were recruited with the assistance of their physicians from The International Center for Spinal Cord Injury, Kennedy Krieger Institute. Inclusion criteria were SCI >6 months previously, medically stable, with no recent (1 month or less) inpatient admission for acute medical or surgical issues. All neurological SCI levels (C1-S1) were eligible. All subjects followed a programme of instruction leading to mastery of basic sailing techniques (steering predetermined courses, sail trimming, tacking, gybing and mark rounding). Results: Not all participants completed the study for various reasons. Those that did were seven males and six females, six with tetraplegia and seven with paraplegia. The mean age was 45 years (23 to 63) and the average time since injury was 14.7 years (2 to 38 years). At the end of the course subjects were able to perform the sailing maneuvers and navigate a triangular racecourse on the simulator's display in 12 knots of wind within a pre-set time. At 6 weeks post completion of training most subjects showed a decrease in depression, physical and social limitations, and an improvement in physical tests. These improvements were maintained or increased in most participants by 12 weeks, but not others. Conclusions: The primary objective of the trial was achieved as all participants who completed the VSail® training were able to sail on the water at the Downtown Sailing Center in Baltimore.

Spinal cord injury can produce a variety of life-limiting chronic impairments, particularly as many occur in young adults. It affects the injured individual, their family, friends and society. Clinical care has improved substantially over the past decades allowing most with spinal injuries to have a normal life span. But many have difficulty in adjusting to the limitations of their new life and are often quite socially isolated. Sailing is usually considered out of reach to most people unless they have a connection through family or friends. It is generally viewed as elitist, expensive and at times dangerous. A view that probably stems from the publicity given to high profile events such as the Americas Cup or long-distance yachting competitions. However, small sailboat sailing is much more available. The problem for even able-bodied people is lack of access to an activity that does appear to carry some risks. For people with spinal injuries sailing seems even more daunting. The aim of this project is to investigate whether use of real time virtual sailing simulators can teach people with spinal cord injury to sail in a safe controlled environment and then easily transition to sail safely and competently on the water. In addition, this project was designed to evaluate the effects on physical and psychological health as well as effects on morale and self-esteem. The study recruited 20 people from the Kennedy Krieger Spinal Institute. They undertook a standard simulator training protocol involving 12 one-hour sessions. For mainly heath-related reasons not all participants completed these sessions. However, all of the 13 participants who completed the simulator training were able to sail in Hansa dinghies in Baltimore Harbor. Each individual showed improvement in most of the physical tests and in a Quality-of-Life Questionnaire and the Veterans RAND 36-Item Health Survey.

Pharmacological characterisation of the CB1 receptor antagonist activity of cannabidiol in the rat vas deferens bioassay.

Cannabidiol is increasingly considered for treatment of a wide range of medical conditions. Binding studies suggest that cannabidiol binds to CB1 receptors. In the rat isolated vas deferens bioassay, a single electrical pulse causes a biphasic contraction from nerve-released ATP and noradrenaline. WIN 55,212-2 acts on prejunctional CB1 receptors to inhibit release of these transmitters. In this bioassay, we tested whether cannabidiol and SR141716 were acting as competitive antagonists of this receptor. Monophasic contractions mediated by ATP or noradrenaline in the presence of prazosin or NF449 (P2X1 inhibitor), respectively, were measured to a single electrical pulse delivered every 30 min. Following treatment with cannabidiol (10-100 µM) or SR141716 (0.003-10 µM), cumulative concentrations of WIN 55,212-2 (0.001-30 µM) were applied followed by a single electrical pulse. The WIN 55,212-2 concentration-contraction curve EC50 values were applied to global regression analysis to determine the pKB. The antagonist potency of cannabidiol at the CB1 receptor in the rat vas deferens bioassay matched the reported receptor binding affinity. Cannabidiol was a competitive antagonist of WIN 55,212-2 with pKB values of 5.90 when ATP was the effector transmitter and 5.29 when it was noradrenaline. Similarly, SR141716 was a competitive antagonist with pKB values of 8.39 for ATP and 7.67 for noradrenaline as the active transmitter. Cannabidiol's low micromolar CB1 antagonist pKB values suggest that at clinical blood levels (1-3 µM) it may act as a CB1 antagonist at prejunctional neuronal sites with more potency when ATP is the effector than for noradrenaline.

Cannabidiol selectively inhibits the contraction of rat small resistance arteries: Possible role for CGRP and voltage-gated calcium channels.

The pharmacology of cannabidiol, the non-psychoactive major component of Cannabis sativa, is of growing interest as it becomes more widely prescribed. This study aimed to examine the effects of cannabidiol on a wide range of contractile agents in rat small resistance arteries, in comparison with large arteries, and to explore its mechanism of action. The vascular actions of cannabidiol were also contrasted with effects on the contractions of bronchial, urogenital, cardiac and skeletal muscles. Isolated small or large arteries were incubated with cannabidiol (0.3-3 µM) or vehicle and concentration-contraction response curves were completed to various agents, including endothelin-1, arginine vasopressin, methoxamine, 5-HT, α-methyl 5-HT and U46619. In small arteries, the effects of cannabidiol were tested in the presence of antagonists of CB1 or CB2 receptors, calcitonin gene-related peptide (CGRP), nitric oxide synthase, cyclooxygenase, PPARγ or a combination. The role of L-type voltage-operated calcium channels was also assessed. Cannabidiol 1-3 µM significantly inhibited the contraction of small resistance arteries to all tested agents through a combination of mechanisms that include CGRP and L-type calcium channels. However, large arteries were insensitive to cannabidiol. Cannabidiol (10-100 µM) was largely without effect in bronchi, atria and hemidiaphragm, but 100 µM attenuated maximum contractions in vasa deferentia. Cannabidiol's effects in the clinical range (1-3 µM) appear to be specific to small resistance arteries. This high sensitivity of the resistance arterial circulation to cannabidiol may offer a therapeutic opportunity in peripheral vascular disease that excludes off-target sites such as the heart and non-vascular smooth muscle.

The Antimicrobial Activity of Cannabinoids.

A post-antibiotic world is fast becoming a reality, given the rapid emergence of pathogens that are resistant to current drugs. Therefore, there is an urgent need to discover new classes of potent antimicrobial agents with novel modes of action. Cannabis sativa is an herbaceous plant that has been used for millennia for medicinal and recreational purposes. Its bioactivity is largely due to a class of compounds known as cannabinoids. Recently, these natural products and their analogs have been screened for their antimicrobial properties, in the quest to discover new anti-infective agents. This paper seeks to review the research to date on cannabinoids in this context, including an analysis of structure-activity relationships. It is hoped that it will stimulate further interest in this important issue.

The effects of varying Mg2+ ion concentrations on contractions to the cotransmitters ATP and noradrenaline in the rat vas deferens.

The vas deferens responds to a single electrical pulse with a biphasic contraction caused by cotransmitters ATP and noradrenaline. Removing Mg2+ (normally 1.2 mM) from the physiological salt solution (PSS) enhances the contraction. This study aimed to determine the effect of Mg2+ concentration on nerve cotransmitter-mediated contractions. Rat vasa deferentia were sequentially bathed in increasing (0, 1.2, 3 mM) or decreasing (3, 1.2, 0 mM) Mg2+ concentrations. At each concentration a single field pulse was applied, and the biphasic contraction recorded. Contractions to exogenous noradrenaline 10 µM and ATP 100 µM were also determined. The biphasic nerve-mediated contraction was elicited by ATP and noradrenaline as NF449 (10 µM) and prazosin (100 nM) completely prevented the respective peaks. Taking the contractions in normal PSS (Mg2+ 1.2 mM) as 100%, lowering Mg2+ to 0 mM enhanced the ATP peak to 170 ±â€¯7% and raising Mg2+ to 3 mM decreased it to 39 ±â€¯3%; the noradrenaline peak was not affected by lowering Mg2+ to 0 mM (97 ±â€¯3%) but was decreased to 63 ±â€¯4% in high Mg2+ (3 mM). Contractions to exogenous ATP, but not noradrenaline, were increased in Mg2+ 0 mM and both were inhibited with Mg2+ 3 mM. Changing Mg2+ concentration affects the contractions elicited by the cotransmitters ATP and noradrenaline. The greatest effects were to potentiate the contraction to ATP in Mg2+ 0 mM and to inhibit the contraction to both ATP and noradrenaline in high Mg2+. Future publications should clearly justify any decision to vary the magnesium concentration from normal (1.2 mM) values.