Consistent Biochemical Data are Essential for Comparability of Botulinum Toxin Type A Products

Pickett, Andy

doi:10.1007/bf03259798

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…Furthermore, since subjects were on average 50–60 years of age, most of them used medication for other conditions. BoNT is a locally acting neurotoxin without systemic effects, and its effect is noticeable after 1 week [ 50 ]. Both scans were performed before this effect could occur; thus it is unlikely that BoNT had a direct effect on striatal DAT or D2/3 binding ratios.…”

Section: Discussionmentioning

confidence: 99%

The relationship between the dopaminergic system and depressive symptoms in cervical dystonia

Zoons

Tijssen

Dreissen

et al. 2017

Eur J Nucl Med Mol Imaging

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PurposeCervical dystonia (CD) is associated with tremor/jerks (50%) and psychiatric complaints (17–70%). The dopaminergic system has been implicated in the pathophysiology of CD in animal and imaging studies. Dopamine may be related to the motor as well as non-motor symptoms of CD. CD is associated with reduced striatal dopamine D2/3 (D2/3) receptor and increased dopamine transporter (DAT) binding. There are differences in the dopamine system between CD patients with and without jerks/tremor and psychiatric symptoms.MethodsPatients with CD and healthy controls underwent neurological and psychiatric examinations. Striatal DAT and D2/3 receptor binding were assessed using [123I]FP-CIT and [123I]IBZM SPECT, respectively. The ratio of specific striatal to non-specific binding (binding potential; BPND) was the outcome measure.ResultsTwenty-seven patients with CD and 15 matched controls were included. Nineteen percent of patients fulfilled the criteria for a depression. Striatal DAT BPND was significantly lower in depressed versus non-depressed CD patients. Higher DAT BPND correlated significantly with higher scores on the Unified Myoclonus Rating Scale (UMRS). The striatal D2/3 receptor BPND in CD patients showed a trend towards lower binding compared to controls. The D2/3 BPND was significantly lower in depressed versus non-depressed CD patients. A significant correlation between DAT and D2/3R BPND was found in both in patients and controls.ConclusionsAlterations of striatal DAT and D2/3 receptor binding in CD patients are related mainly to depression. DAT BPND correlates significantly with scores on the UMRS, suggesting a role for dopamine in the pathophysiology of tremor/jerks in CD.

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Section: Discussionmentioning

confidence: 99%

The relationship between the dopaminergic system and depressive symptoms in cervical dystonia

Zoons

Tijssen

Dreissen

et al. 2017

Eur J Nucl Med Mol Imaging

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“…The main focus of the letter to the editor by Dr Pickett[1] is the interchangeability of botulinum toxin A dosages between products, and therefore this answer will address this issue.…”

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confidence: 99%

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Frevert

2011

Drugs R D

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Frevert¹

2011

Drugs R D

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The purpose of Dr Frevert's article was to compare the neurotoxin content of each of the BoNT-A products in the vial. [1] A new figure has now appeared for Xeomin Ò , 0.44 ng per vial, as compared to the 0.6 ng previously published. [16] This finding is somewhat dismissed as a technical issue but, in reality, represents a 27% reduction. Could this be due to changes in the product since the data were first reported or the product first used (perhaps changes in batches of active component, for example, see Quarta [17] or other issues)? Whatever the cause, this significant difference is a product inconsistency that warranted further comment, representing an important aspect of the work to the cliniciansconsistent product gives consistent clinical results. Data comparing the characteristics of the various BoNT-A products and misleadingly comparing these to labeled units are not helping clinicians select products for use. Instead, detailed overall data, notably on history of product consistency, such as those previously published for Dysport Ò , [10] are important for clinicians and these are still awaited for the other BoNT-A products. Perhaps the time has also come to stop discussing BoNT-A complex 'sizes' in a clinical context unless and until data are produced that clearly demonstrate any relevance to clinical use? None now seem likely.

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Consistent Biochemical Data are Essential for Comparability of Botulinum Toxin Type A Products

Cited by 3 publications

References 11 publications

The relationship between the dopaminergic system and depressive symptoms in cervical dystonia

The relationship between the dopaminergic system and depressive symptoms in cervical dystonia

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