Dose equivalence of two commercial preparations of botulinum neurotoxin type A: time for a reassessment?

International audienceBACKGROUND: The units of different preparations of botulinum neurotoxin type A (BoNT-A) have different potencies, and dosing recommendations for each product are not interchangeable. Historically, there has been debate concerning the dose-equivalence ratio that should be used in clinical practice. METHODS: Published evidence was considered to establish an appropriate dose-conversion ratio for the two main commercially available preparations of BoNT-A--Dysport (Dp) and Botox (Bx). RESULTS: Four key areas of evidence were identified: nonclinical and preclinical studies; studies exploring the diffusion characteristics and effects of complexing proteins; comparative experimental data from human studies; and clinical studies. Nonclinical data indicate that the principal reasons for differences in unit potency between the two products are dilution artefacts in the mouse assay. Use of saline as a diluent, at high dilutions, results in significant loss of potency in the Bx assay, whereas use of gelatin phosphate buffer in the Dp assay procedure protects the toxin during dilution. The published data on mouse assays show a Dp : Bx unit ratio range of 2.3-2.5 : 1 in saline and 1.8-3.2 : 1 in gelatin phosphate buffer. Data indicate that complexing proteins or size of the complex, which is highly pH sensitive, play no role in toxin diffusion and that Dp and Bx have similar diffusion characteristics when used at comparable doses. Randomized, controlled clinical studies indicate that 3 : 1 is more appropriate than 4 : 1, but the two products are not equivalent at this ratio. Comparative human experimental studies using the extensor digitorum brevis test, facial lines and anhidrotic action halo tests support dose-conversion ratios less than 3 : 1. LIMITATIONS: Data comparing dose equivalence ratios from the non-clinical setting should be extrapolated into the clinical setting with some caution. CONCLUSIONS: Dose-conversion ratios between Dp and Bx of 4 : 1 and greater are not supported by the recent literature

Cross-sectional TEM study on metal/carbon nanotube interface

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004

Non-vitamin K antagonist oral anticoagulants in patients with an increased risk of bleeding

The non-vitamin K antagonist oral anticoagulants (NOACs) have considerably changed clinical practice and are increasingly being used as an alternative to vitamin K antagonists (VKAs) for 3 main reasons: 1) an improved benefit-risk ratio (in particular lower rates of intracranial bleeding), 2) a more predictable effect without the need for routine monitoring, and 3) fewer food and drug interactions compared with VKAs. Currently, there are four NOACs available: the factor Xa inhibitors apixaban, edoxaban, and rivaroxaban, and the thrombin inhibitor dabigatran. This consensus paper reviews the properties and usage of NOACs in a number of high-risk patient populations, such as patients with chronic kidney disease, patients 80 years of age and others and provides guidance for the use of NOACs in patients at risk of bleeding.(VLID)362005

The First Case(s) of Botulism in Vienna in 21 Years: A Case Report

We describe two linked cases of botulinum toxin intoxication to provide the clinician with a better idea about how botulism cases may present since early diagnosis and treatment are crucial in botulism. Botulinum toxin is the strongest neurotoxin known. Methods: We review the available literature, the compiled clinical data, and observations. Results: After a slow onset of clinical signs a married couple living in Vienna presented with dysphagia, difficulties in accommodation, inability to sweat, urinary and stool retention, dizziness, and nausea. They suffered intoxication with botulinum toxin type B. Botulism is a rarely occurring disease in Austria. In the last 21 years there were only twelve reported cases. Conclusion: Both patients went to a general practitioner as well as several specialists before they were sent to and correctly diagnosed at our outpatient department. To avoid long delays between intoxication and diagnosis we think it is crucial to advert to the complex symptoms a nonsevere intoxication with botulinum toxin can produce, especially since intoxications have become rare occurrences in the industrialized societies due to the high quality of industrial food production