An agonist of CXCR4 induces a rapid recovery from the neurotoxic effects of Vipera ammodytes and Vipera aspis venoms.

People bitten by Alpine vipers are usually treated with antivenom antisera to prevent the noxious consequences caused by the injected venom. However, this treatment suffers from a number of drawbacks and additional therapies are necessary. The venoms of Vipera ammodytes and of Vipera aspis are neurotoxic and cause muscle paralysis by inducing neurodegeneration of motor axon terminals because they contain a presynaptic acting sPLA2 neurotoxin. We have recently found that any type of damage to motor axons is followed by the expression and activation of the intercellular signaling axis consisting of the CXCR4 receptor present on the membrane of the axon stump and of its ligand, the chemokine CXCL12 released by activated terminal Schwann cells. We show here that also V. ammodytes and V. aspis venoms cause the expression of the CXCL12-CXCR4 axis. We also show that a small molecule agonist of CXCR4, dubbed NUCC-390, induces a rapid regeneration of the motor axon terminal with functional recovery of the neuromuscular junction. These findings qualify NUCC-390 as a promising novel therapeutics capable of improving the recovery from the paralysis caused by the snakebite of the two neurotoxic Alpine vipers.

Characterization of a membrane binding loop leads to engineering botulinum neurotoxin B with improved therapeutic efficacy.

Botulinum neurotoxins (BoNTs) are a family of bacterial toxins with seven major serotypes (BoNT/A-G). The ability of these toxins to target and bind to motor nerve terminals is a key factor determining their potency and efficacy. Among these toxins, BoNT/B is one of the two types approved for medical and cosmetic uses. Besides binding to well-established receptors, an extended loop in the C-terminal receptor-binding domain (HC) of BoNT/B (HC/B) has been proposed to also contribute to toxin binding to neurons by interacting with lipid membranes (termed lipid-binding loop [LBL]). Analogous loops exist in the HCs of BoNT/C, D, G, and a chimeric toxin DC. However, it has been challenging to detect and characterize binding of LBLs to lipid membranes. Here, using the nanodisc system and biolayer interferometry assays, we find that HC/DC, C, and G, but not HC/B and HC/D, are capable of binding to receptor-free lipids directly, with HC/DC having the highest level of binding. Mutagenesis studies demonstrate the critical role of consecutive aromatic residues at the tip of the LBL for binding of HC/DC to lipid membranes. Taking advantage of this insight, we then create a "gain-of-function" mutant HC/B by replacing two nonaromatic residues at the tip of its LBL with tryptophan. Cocrystallization studies confirm that these two tryptophan residues do not alter the structure of HC/B or the interactions with its receptors. Such a mutated HC/B gains the ability to bind receptor-free lipid membranes and shows enhanced binding to cultured neurons. Finally, full-length BoNT/B containing two tryptophan mutations in its LBL, together with two additional mutations (E1191M/S1199Y) that increase binding to human receptors, is produced and evaluated in mice in vivo using Digit Abduction Score assays. This mutant toxin shows enhanced efficacy in paralyzing local muscles at the injection site and lower systemic diffusion, thus extending both safety range and duration of paralysis compared with the control BoNT/B. These findings establish a mechanistic understanding of LBL-lipid interactions and create a modified BoNT/B with improved therapeutic efficacy.

A Dose-finding Study of Sugammadex for Reversal of Rocuronium in Cardiac Surgery Patients and Postoperative Monitoring for Recurrent Paralysis.

BACKGROUND: The dose of sugammadex recommended by the manufacturer for reversal of rocuronium is 2 mg/kg when the train-of-four count is 2 or more and 4 mg/kg when it is less than 2 but there is a posttetanic count of at least 1. The purpose of this dose-finding study was to titrate sugammadex to produce a train-of-four ratio 0.9 or greater at the conclusion of cardiac surgery, and to continue monitoring neuromuscular blockade in the intensive care unit to identify recurrent paralysis. The hypothesis was that many patients would require less than the recommended dose of sugammadex, but that some would require more, and that recurrent paralysis would not occur. METHODS: Neuromuscular blockade was monitored using electromyography during cardiac surgery. Administration of rocuronium was at the discretion of the anesthesia care team. During sternal closure, sugammadex was titrated in 50-mg increments every 5 min until a train-of-four ratio 0.9 or greater was obtained. Neuromuscular blockade was monitored with electromyography in the intensive care unit until sedation was discontinued before extubation or for a maximum of 7 h. RESULTS: Ninety-seven patients were evaluated. The dose of sugammadex required to achieve a train-of-four ratio of 0.9 or greater varied from 0.43 to 5.6 mg/kg. There was a statistically significant relationship between the depth of neuromuscular blockade and the sugammadex dose required for reversal, but there was a large variation in dose required at any depth of neuromuscular blockade. Eighty-four of 97 patients (87%) required less than the recommended dose, and 13 (13%) required more. Two patients required additional sugammadex administration for recurrent paralysis. CONCLUSIONS: When sugammadex was titrated to effect, the dose was usually less than the recommended dose, but it was more in some patients. Therefore, quantitative twitch monitoring is essential for ascertaining that adequate reversal has taken place after sugammadex administration. Recurrent paralysis was observed in two patients.

Peri-Intubation Hypoxia After Delayed Versus Rapid Sequence Intubation in Critically Injured Patients on Arrival to Trauma Triage: A Randomized Controlled Trial.

BACKGROUND: Critically injured patients who are agitated and delirious on arrival do not allow optimal preoxygenation in the emergency area. We investigated whether the administration of intravenous (IV) ketamine 3 minutes before administration of a muscle relaxant is associated with better oxygen saturation levels while intubating these patients. METHODS: Two hundred critically injured patients who required definitive airway management on arrival were recruited. The subjects were randomized as delayed sequence intubation (group DSI) or rapid sequence intubation (group RSI). In group DSI, patients received a dissociative dose of ketamine followed by 3 minutes of preoxygenation and paralysis using IV succinylcholine for intubation. In group RSI, a 3-minute preoxygenation was performed before induction and paralysis using the same drugs, as described conventionally. The primary outcome was incidence of peri-intubation hypoxia. Secondary outcomes were first-attempt success rate, use of adjuncts, airway injuries, and hemodynamic parameters. RESULTS: Peri-intubation hypoxia was significantly lower in group DSI (8 [8%]) compared to group RSI (35 [35%]; P = .001). First-attempt success rate was higher in group DSI (83% vs 69%; P = .02). A significant improvement in mean oxygen saturation levels from baseline values was seen in group DSI only. There was no incidence of hemodynamic instability. There was no statistically significant difference in airway-related adverse events. CONCLUSIONS: DSI appears promising in critically injured trauma patients who do not allow adequate preoxygenation due to agitation and delirium and require definitive airway on arrival.

Neuro-ophthalmologic symptoms after coronavirus disease 2019 vaccination: a retrospective study.

BACKGROUND: There have been several studies on inflammatory ophthalmic diseases; however, few studies have reported neuro-ophthalmological symptoms, such as diplopia and ocular motor nerve palsy, after coronavirus disease 2019 (COVID-19) vaccination. Therefore, this study aimed to report neuro-ophthalmological symptoms in patients after COVID-19 vaccination. METHODS: This was a retrospective study based on the medical records of 10 patients who visited our ophthalmology clinic in 2021 with symptoms, such as diplopia (nine patients) and decreased visual acuity (one patient), and showed findings, such as ocular motor nerve palsy, after vaccination against COVID-19. RESULTS: One patient had third nerve palsy, two had sixth nerve palsy, and five had fourth nerve palsy. One patient complained of subjective binocular diplopia but all test results were normal. One patient presented with decreased visual acuity accompanied by a sudden increase in intraocular pressure and orbital cellulitis in the other eye. The symptoms improved gradually in most patients. Compared with previous studies, this study reported three cases of antiplatelet therapy that was initiated due to the older age of the patients and underlying diseases. CONCLUSION: As COVID-19 vaccines can cause neuro-ophthalmological diseases, such as ocular motor nerve palsy, patients' age and underlying diseases should be considered while administering them.

Asymptomatic unilateral phrenic nerve palsy after bortezomib treatment in a newly diagnosed multiple myeloma patient.

INTRODUCTION: Bortezomib is the first chemotherapeutic agent of proteosome inhibitor class that can be used in newly diagnosed and relapsed/refractory multiple myeloma. It is well known that bortezomib has side effects such as peripheral sensory, motor, or autonomic neuropathy. In this paper, we will present our patient who developed unilateral phrenic nerve palsy as an autonomic neuropathy after six cycles of subcutaneous bortezomib treatment. This case differs from other cases in that our patient was asymptomatic. CASE REPORT: A 57-year-old male patient was admitted with back pain and gait disturbances. In the thorax computed tomography, a soft tissue mass causing compression on the spinal canal was observed in the T12 vertebra. Bone biopsy pathology report resulted in diffuse plasma cell infiltration. The patient was diagnosed with stage ISS-3, IgG kappa type multiple myeloma. MANAGEMENT AND OUTCOME: Subcutaneous bortezomib 1 × 2.2 mg (Days 1-4-8-11) + intravenous cyclophosphamide 1000 mg (Day 1) + intravenous dexamethasone 40 mg (Days 1-2-3-4) (VCD chemotherapy protocol) was started. Totally six cycles of VCD were administered. While the patient did not have any respiratory symptoms, an elevation consistent with phrenic nerve palsy was observed in the left hemidiaphragm in the thorax computed tomography that was taken during the preparation for autologous hematopoietic stem cell transplantation. DISCUSSION: Bortezomib is a frequently used chemotherapeutic agent in patients with multiple myeloma and care should be taken in terms of the risk of developing phrenic nerve palsy in patients. There are cases of autonomic neuropathy developing after bortezomib treatment.

Peri-operative management of neuromuscular blockade: A guideline from the European Society of Anaesthesiology and Intensive Care.

Recent data indicated a high incidence of inappropriate management of neuromuscular block, with a high rate of residual paralysis and relaxant-associated postoperative complications. These data are alarming in that the available neuromuscular monitoring, as well as myorelaxants and their antagonists basically allow well tolerated management of neuromuscular blockade. In this first European Society of Anaesthesiology and Intensive Care (ESAIC) guideline on peri-operative management of neuromuscular block, we aim to present aggregated and evidence-based recommendations to assist clinicians provide best medical care and ensure patient safety. We identified three main clinical questions: Are myorelaxants necessary to facilitate tracheal intubation in adults? Does the intensity of neuromuscular blockade influence a patient's outcome in abdominal surgery? What are the strategies for the diagnosis and treatment of residual paralysis? On the basis of this, PICO (patient, intervention, comparator, outcome) questions were derived that guided a structured literature search. A stepwise approach was used to reduce the number of trials of the initial research ( n  = 24 000) to the finally relevant clinical studies ( n  = 88). GRADE methodology (Grading of Recommendations, Assessment, Development and Evaluation) was used for formulating the recommendations based on the findings of the included studies in conjunction with their methodological quality. A two-step Delphi process was used to determine the agreement of the panel members with the recommendations: R1 We recommend using a muscle relaxant to facilitate tracheal intubation (1A). R2 We recommend the use of muscle relaxants to reduce pharyngeal and/or laryngeal injury following endotracheal intubation (1C). R3 We recommend the use of a fast-acting muscle relaxant for rapid sequence induction intubation (RSII) such as succinylcholine 1 mg kg -1 or rocuronium 0.9 to 1.2 mg kg -1 (1B). R4 We recommend deepening neuromuscular blockade if surgical conditions need to be improved (1B). R5 There is insufficient evidence to recommend deep neuromuscular blockade in general to reduce postoperative pain or decrease the incidence of peri-operative complications. (2C). R6 We recommend the use of ulnar nerve stimulation and quantitative neuromuscular monitoring at the adductor pollicis muscle to exclude residual paralysis (1B). R7 We recommend using sugammadex to antagonise deep, moderate and shallow neuromuscular blockade induced by aminosteroidal agents (rocuronium, vecuronium) (1A). R8 We recommend advanced spontaneous recovery (i.e. TOF ratio >0.2) before starting neostigmine-based reversal and to continue quantitative monitoring of neuromuscular blockade until a TOF ratio of more than 0.9 has been attained. (1C).

Comparison of ultrasound-guided supraclavicular and costoclavicular brachial plexus blocks in pediatric patients: a randomized clinical trial.

PURPOSE: Costoclavicular brachial plexus block has been described recently as a new technique in adults and pediatric patients. In this study, we aimed to compare the supraclavicular and costoclavicular approaches, which are claimed to be effective and practical in pediatric patients. METHODS: Sixty children were randomized to receive supraclavicular (SC group) or costoclavicular (CC group) brachial plexus blocks prior to surgical incision. Block performance times were recorded as the primary outcome. Procedural features (ideal brachial plexus cord visualization/needle pathway planning time, needle tip/shaft visualization difficulty, number of needle maneuvers, requirement of extra needle maneuvers due to insufficient local anesthetic distribution) and postoperative pain-related data (sensorimotor block intensities, Wong-Baker and FLACC pain scores and analgesic requirements) were also evaluated. To observe the tendency toward respiratory complications, ultrasonographic diaphragm movement amplitude (with M-mode) and diaphragm thickness (with B-mode) were measured postoperatively. RESULTS: A total of 56 patients were included. Block performance times [70(7-97) vs. 115(75-180) s] were significantly lower in the CC group (p < 0.01). The block success rates did not differ (p > 0.05). The incidence of hemidiaphragm paralysis was 44% in the SC group (p < 0.001), and inspiratory diaphragm thickness was significantly lower (p < 0.01). None of CC group patients experienced hemidiaphragm paralysis. All other parameters were comparable (p > 0.05). CONCLUSIONS: Although costoclavicular block did not show superiority in pain management, the block performance was perceived as more practical than supraclavicular block. We believe that costoclavicular brachial plexus block stands as a good option in upper extremity surgeries with the advantages of shorter block performance time and reduced ipsilateral hemidiaphragm paralysis risk in pediatric patients.

Transient left phrenic nerve paralysis after ethanol infusion into the vein of Marshall.

An 80-year-old man underwent catheter ablation for atrial tachycardia (AT), which developed after catheter ablation for atrial fibrillation. The AT was diagnosed as dual-loop tachycardia, which included peri-mitral and roof-dependent ATs. An ethanol infusion into the vein of Marshall resulted in left phrenic nerve paralysis. During the procedure, the phrenic nerve paralysis was completely relieved.

The Action of Botulinum Toxin A on the Sternocleidomastoid Muscle: An Experimental Study on Rats.

In this study, we aim to investigate the effective dose of botulinum neurotoxin A that results in paralysis of the sternocleidomastoid muscle for a minimum duration of 28 days in Wistar rats. This research is the first in a series of studies to investigate the value of botulinum toxin A in the healing of clavicle fractures through the temporary paralysis of the sternocleidomastoid. A surgical incision was made under general anaesthesia, and botulinum neurotoxin A in respective doses of 4 and 6 international units (IU) or normal saline in equivalent volumes were injected directly into the exposed muscle. Electromyography was conducted on days 0, 7, and 28 following substance administration to determine the extent of muscle paralysis. Electromyography on day 0 showed no paralysis in either group. Animals injected with neurotoxin all exhibited paralysis on days 7 and 28 that was weaker in the group injected with the smaller dose of 4 IU. One death occurred in the group injected with the higher dose (6 IU), whereas in the control group, no paralysis was seen. Botulinum neurotoxin A in a dose of 6 IU resulted in complete paralysis of the sternocleidomastoid in rats for a minimum of 28 days. A dose of 4 IU resulted in less potent paralysis but was safer in our research. Botulinum neurotoxin is a substance utilised in cosmetics and therapeutics for many years, yet research shows that its use can be expanded to target a wider range of pathologies. In this series of studies, we aim to explore the neurotoxin's applications on the treatment of clavicle fractures. To investigate this, we need to first establish the duration of its action on the sternocleidomastoid muscle.

Diterpenoid Caesalmin C Delays Aß-Induced Paralysis Symptoms via the DAF-16 Pathway in Caenorhabditis elegans.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in the world. However, there is no effective drug to cure it. Caesalmin C is a cassane-type diterpenoid abundant in Caesalpinia bonduc (Linn.) Roxb. In this study, we investigated the effect of caesalmin C on Aß-induced toxicity and possible mechanisms in the transgenic Caenorhabditis elegans AD model. Our results showed that caesalmin C significantly alleviated the Aß-induced paralysis phenotype in transgenic CL4176 strain C. elegans. Caesalmin C dramatically reduced the content of Aß monomers, oligomers, and deposited spots in AD C. elegans. In addition, mRNA levels of sod-3, gst-4, and rpt-3 were up-regulated, and mRNA levels of ace-1 were down-regulated in nematodes treated with caesalmin C. The results of the RNAi assay showed that the inhibitory effect of caesalmin C on the nematode paralysis phenotype required the DAF-16 signaling pathway, but not SKN-1 and HSF-1. Further evidence suggested that caesalmin C may also have the effect of inhibiting acetylcholinesterase (AchE) and upregulating proteasome activity. These findings suggest that caesalmin C delays the progression of AD in C. elegans via the DAF-16 signaling pathway and that it could be developed into a promising medication to treat AD.

Red-Beet Betalain Pigments Inhibit Amyloid-ß Aggregation and Toxicity in Amyloid-ß Expressing Caenorhabditis elegans.

Betalain pigments are mainly produced by plants belonging to the order of Caryophyllales. Betalains exhibit strong antioxidant activity and responds to environmental stimuli and stress in plants. Recent reports of antioxidant, anti-inflammatory and anti-cancer properties of betalain pigments have piqued interest in understanding their biological functions. We investigated the effects of betalain pigments (betanin and isobetanin) derived from red-beet on amyloid-ß (Aß) aggregation, which causes Alzheimer's disease. Non-specific inhibition of Aß aggregation against Aß40 and Aß42 by red-beet betalain pigments, in vitro was demonstrated using the thioflavin t fluorescence assay, circular dichroism spectroscopy analysis, transmission electron microscopy and nuclear magnetic resonance (NMR) analysis. Furthermore, we examined the ability of red-beet betalain pigments to interfere with Aß toxicity by using the transgenic Caenorhabditis elegans model, which expresses the human Aß42 protein intracellularly within the body wall muscle. It responds to Aß-toxicity with paralysis and treatment with 50 µM red-beet betalain pigments significantly delayed the paralysis of C. elegans. These results suggest that betalain pigments reduce Aß-induced toxicity.

Serial Systemic Injections of Endotoxin (LPS) Elicit Neuroprotective Spinal Cord Microglia through IL-1-Dependent Cross Talk with Endothelial Cells.

Microglia are dynamic immunosurveillance cells in the CNS. Whether microglia are protective or pathologic is context dependent; the outcome varies as a function of time relative to the stimulus, activation state of neighboring cells in the microenvironment or within progression of a particular disease. Although brain microglia can be "primed" using bacterial lipopolysaccharide (LPS)/endotoxin, it is unknown whether LPS delivered systemically can also induce neuroprotective microglia in the spinal cord. Here, we show that serial systemic injections of LPS (1 mg/kg, i.p., daily) for 4 consecutive days (LPSx4) consistently elicit a reactive spinal cord microglia response marked by dramatic morphologic changes, increased production of IL-1, and enhanced proliferation without triggering leukocyte recruitment or overt neuropathology. Following LPSx4, reactive microglia frequently contact spinal cord endothelial cells. Targeted ablation or selective expression of IL-1 and IL-1 receptor (IL-1R) in either microglia or endothelia reveal that IL-1-dependent signaling between these cells mediates microglia activation. Using a mouse model of ischemic spinal cord injury in male and female mice, we show that preoperative LPSx4 provides complete protection from ischemia-induced neuron loss and hindlimb paralysis. Neuroprotection is partly reversed by either pharmacological elimination of microglia or selective removal of IL-1R in microglia or endothelia. These data indicate that spinal cord microglia are amenable to therapeutic reprogramming via systemic manipulation and that this potential can be harnessed to protect the spinal cord from injury.SIGNIFICANCE STATEMENT Data in this report indicate that a neuroprotective spinal cord microglia response can be triggered by daily systemic injections of LPS over a period of 4 d (LPSx4). The LPSx4 regimen induces morphologic transformation and enhances proliferation of spinal cord microglia without causing neuropathology. Using advanced transgenic mouse technology, we show that IL-1-dependent microglia-endothelia cross talk is necessary for eliciting this spinal cord microglia phenotype and also for conferring optimal protection to spinal motor neurons from ischemic spinal cord injury (ISCI). Collectively, these novel data show that it is possible to consistently elicit spinal cord microglia via systemic delivery of inflammogens to achieve a therapeutically effective neuroprotective response against ISCI.

Amyloid-beta induced paralysis is reduced by cholecalciferol through inhibition of the steroid-signaling pathway in an Alzheimer model of Caenorhabditis elegans.

Objectives: Alzheimer's disease (AD) is a neurodegenerative disorder resulting from the accumulation of toxic ß-amyloid (Aß) aggregates in the human brain. Epidemiological studies have shown that elevated cholesterol plasma levels are associated with the development of AD and we have previously shown that cholesterol restriction reduces the Aß-induced paralysis in an Alzheimer model of the nematode Caenorhabditis elegans. In the present study we investigated the effects of the cholesterol homolog cholecalciferol, i.e. vitamin D, on Aß-induced paralysis in C. elegans and its interference with the steroid-signaling pathway. Methods: Aß-induced paralysis was assessed in the C. elegans strain CL2006, expressing human Aß1-42 under control of a muscle-specific promoter. Knockdown of members of the steroid-signaling pathway was achieved by RNA interference (RNAi). Nuclear translocation of foxo transcription factor DAF-16 was visualized using the strain TJ356, carrying a daf-16::gfp transgene. Results: Cholecalciferol at a concentration of 1 µM reduced the Aß-induced paralysis in CL2006 significantly, which was reverted by increasing the cholesterol concentration in the medium. Knockdown of nhr-8, daf-36, daf-9 or daf-12, all reduced Aß-induced paralysis to the same extent as cholecalciferol with no additional or synergistic effects under co-application. Functional DAF-16 proved to be crucial for the effects of cholecalciferol and DAF-16 nuclear translocation was increased by cholecalciferol and also RNAi versus nhr-8, daf-36, daf-9 or daf-12 with no additive or synergistic effects. Conclusions: Our results suggest, that cholecalciferol inhibits Aß-induced paralysis in C. elegans through inhibition of steroid-signaling and the concomitant nuclear translocation of DAF-16.

Residual paralysis caused by 50 mg rocuronium after reversal with 4 mg/kg sugammadex: a case report.

BACKGROUND: Rocuronium-induced neuromuscular blockade can be quickly and completely reversed by administration of an optimal dose of sugammadex. Sugammadex antagonizes rocuronium-induced neuromuscular blockade by encapsulating rocuronium. Herein, we report a case of residual neuromuscular paralysis in which the recommended dose of sugammadex (4 mg·kg- 1) failed to antagonize a rocuronium-induced blockade. CASE PRESENTATION: A 71-year-old man (body mass index: 26.7 kg·m- 2) underwent endoscopic submucosal dissection of early-stage gastric cancer. He had no known factors that may have affected the effects of rocuronium and sugammadex. He received rocuronium (50 mg; 0.7 mg·kg- 1) for anesthesia induction. No additional rocuronium was administered during the 71-min procedure. Ninety-four minutes after rocuronium administration, neuromuscular monitoring showed 20 twitches in response to post-tetanic count stimulation. The train-of-four (TOF) ratio was not measurable despite sugammadex (280 mg; 4 mg/kg) administration, although four weak twitches in response to TOF stimulation appeared in 3 min. The TOF ratio became detectable following administration of an additional dose of sugammadex (120 mg; 1.7 mg·kg- 1), and it recovered to 107% 8 min after the second dose. The patient opened his eyes; moved his neck, arms, and limbs; and regained consciousness. The trachea was extubated and the patient was transferred to the ward. CONCLUSIONS: Neuromuscular monitoring should be used if a neuromuscular blockage agent is administered, even if the recommended dose of sugammadex is administered.

Involvement of dopamine receptor in the actions of non-psychoactive phytocannabinoids.

Nematode Caenorhabditis elegans (C. elegans) exhibited a vigorous swimming behavior in liquid medium. Addition of dopamine inhibited the swimming behavior, causing paralysis in 65% of wild-type nematodes. Interestingly, phytocannabinoids cannabidiol (CBD) or cannabidivarin (CBDV), caused paralysis in 40% of the animals. Knockout of DOP-3, the dopamine D2-like receptor critical for locomotor behavior, eliminated the paralysis induced by dopamine, CBD, and CBDV. In contrast, both CBD and CBDV caused paralysis in animals lacking CAT-2, an enzyme necessary for dopamine synthesis. Co-administration of dopamine with either CBD or CBDV caused paralysis similar to that of either phytocannabinoid treatment alone. These data support the notion that CBD and CBDV act as functional partial agonists on dopamine D2-like receptors in vivo. The discovery that dopamine receptor is involved in the actions of phytocannabinoids moves a significant step toward our understanding of the mechanisms for medical uses of cannabis in the treatment of neurological and psychiatric disorders.

Application of Six Detection Methods for Analysis of Paralytic Shellfish Toxins in Shellfish from Four Regions within Latin America.

With the move away from use of mouse bioassay (MBA) to test bivalve mollusc shellfish for paralytic shellfish poisoning (PSP) toxins, countries around the world are having to adopt non-animal-based alternatives that fulfil ethical and legal requirements. Various assays have been developed which have been subjected to single-laboratory and multi-laboratory validation studies, gaining acceptance as official methods of analysis and approval for use in some countries as official control testing methods. The majority of validation studies conducted to date do not, however, incorporate shellfish species sourced from Latin America. Consequently, this study sought to investigate the performance of five alternative PSP testing methods together with the MBA, comparing the PSP toxin data generated both qualitatively and quantitatively. The methods included a receptor binding assay (RBA), two liquid chromatography with fluorescence detection (LC-FLD) methods including both pre-column and post-column oxidation, liquid chromatography with tandem mass spectrometry (LC-MS/MS) and a commercial lateral flow assay (LFA) from Scotia. A total of three hundred and forty-nine shellfish samples from Argentina, Mexico, Chile and Uruguay were assessed. For the majority of samples, qualitative results compared well between methods. Good statistical correlations were demonstrated between the majority of quantitative results, with a notably excellent correlation between the current EU reference method using pre-column oxidation LC-FLD and LC-MS/MS. The LFA showed great potential for qualitative determination of PSP toxins, although the findings of high numbers of false-positive results and two false negatives highlighted that some caution is still needed when interpreting results. This study demonstrated that effective replacement methods are available for countries that no longer wish to use the MBA, but highlighted the importance of comparing toxin data from the replacement method using local shellfish species of concern before implementing new methods in official control testing programs.

Severe Acquired Hypokalemic Paralysis in a Bodybuilder After Self-Medication With Triamterene/Hydrochlorothiazide.

BACKGROUND: Severe hypokalemia with severe neurological impairment and electrocardiogram (ECG) abnormalities due to the misuse of triamterene/hydrochlorothiazide (HCTZ) in a bodybuilder has not yet been reported. CASE REPORT: A 22-year-old bodybuilder developed acute generalized muscle cramps, sensory disturbance of the distal lower and upper limbs, quadriparesis, and urinary retention. These abnormalities were attributed to severe hypokalemia of 1.8 mmol/L (normal range 3.4-4.5 mmol/L) due to misuse of triamterene/HCTZ together with fluid restriction. He was cardiologically asymptomatic, but ECG revealed a corrected QT (QTc) interval of 625 ms. On intravenous application of fluids along with intravenous and oral substitution of potassium, his condition rapidly improved, such that the sensory disturbances, quadriparesis, and bladder dysfunction completely resolved within 2 days after admission. CONCLUSIONS: Self-medication with diuretics along with fluid restriction may result in severe hypokalemia, paralysis, and ECG abnormalities. Those responsible for the management of bodybuilding studios and competitions must be aware of the potential severe health threats caused by self-medication with diuretics and anabolic steroids. Although triamterene is potassium-sparing, it may enhance the potassium-lowering effect of HCTZ.

Superior Trunk Block: A Phrenic-sparing Alternative to the Interscalene Block: A Randomized Controlled Trial.

BACKGROUND: Interscalene nerve blockade remains one of the most commonly used anesthetic and analgesic approaches for shoulder surgery. The high incidence of hemidiaphragmatic paralysis associated with the block, however, precludes its use among patients with compromised pulmonary function. To address this issue, recent studies have investigated phrenic-sparing alternatives that provide analgesia. None, however, have been able to reliably demonstrate surgical anesthesia without significant risk for hemidiaphragmatic paralysis. The utility of the superior trunk block has yet to be studied. The hypothesis was that compared with the interscalene block, the superior trunk block will provide noninferior surgical anesthesia and analgesia while sparing the phrenic nerve. METHODS: This randomized controlled trial included 126 patients undergoing arthroscopic ambulatory shoulder surgery. Patients either received a superior trunk block (n = 63) or an interscalene block (n = 63). The primary outcomes were the incidence of hemidiaphragmatic paralysis and worst pain score in the recovery room. Ultrasound was used to assess for hemidiaphragmatic paralysis. Secondary outcomes included noninvasively measured parameters of respiratory function, opioid consumption, handgrip strength, adverse effects, and patient satisfaction. RESULTS: The superior trunk group had a significantly lower incidence of hemidiaphragmatic paralysis compared with the interscalene group (3 of 62 [4.8%] vs. 45 of 63 [71.4%]; P < 0.001, adjusted odds ratio 0.02 [95% CI, 0.01, 0.07]), whereas the worst pain scores in the recovery room were noninferior (0 [0, 2] vs. 0 [0, 3]; P = 0.951). The superior trunk group were more satisfied, had unaffected respiratory parameters, and had a lower incidence of hoarseness. No difference in handgrip strength or opioid consumption were detected. Superior trunk block was associated with lower worst pain scores on postoperative day 1. CONCLUSIONS: Compared with the interscalene block, the superior trunk block provides noninferior surgical anesthesia while preserving diaphragmatic function. The superior trunk block may therefore be considered an alternative to traditional interscalene block for shoulder surgery.

Defining the role of post-synaptic α-neurotoxins in paralysis due to snake envenoming in humans.

Snake venom α-neurotoxins potently inhibit rodent nicotinic acetylcholine receptors (nAChRs), but their activity on human receptors and their role in human paralysis from snakebite remain unclear. We demonstrate that two short-chain α-neurotoxins (SαNTx) functionally inhibit human muscle-type nAChR, but are markedly more reversible than against rat receptors. In contrast, two long-chain α-neurotoxins (LαNTx) show no species differences in potency or reversibility. Mutant studies identified two key residues accounting for this. Proteomic and clinical data suggest that paralysis in human snakebites is not associated with SαNTx, but with LαNTx, such as in cobras. Neuromuscular blockade produced by both subclasses of α-neurotoxins was reversed by antivenom in rat nerve-muscle preparations, supporting its effectiveness in human post-synaptic paralysis.