Botulinum toxins Flashcards
Botulinum toxin is a neurotoxin produced by Clostridium botulinum, a Gram-positive anaerobic bacterium.
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Botulinum toxin binds to the cholinergic receptors, enabling acetylchloline release, which prevents muscular contraction of the affected muscles.
F Blocks acetylcholine release.
Botox and Dysport are type B botulinum toxins.
F Type A.
The duration of botulinum toxin-B is shorter than toxin-A.
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Botulinum toxin binds selectively and reversibly to cholinergic nerve terminals, mediated by its heavy chain.
F Binds irreversibly.
The light chain of botulinium is specific for cholinergic action and promotes the light chain translocation through the endosomal membrane
F Heavy chain
Once inside the cytoplasm, the botulinum toxin light chain blocks the release of Ach.
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Botulinum toxin inhibits sweat production by blocking ACH release in the autonomous cholinergic fibres from sympathetic fibres of the sweat glands.
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Dynamic wrinkles are those caused or aggravated by muscular contraction, whereas static wrinkles are apparent even if facial muscles are relaxed.
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Initially, the dynamic wrinkles on the forehead appear parallel to the direction of the muscle fibres, and become static over time.
F Perpendicular rather than parallel.
Within the mid face, ageing changes are due to remodelling of the osseous and cartilaginous structures, loss of elasticity and of subcutaneous tissues, as well as muscle relaxation.
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In the lower face, muscular hyperactivity and volumetric losses of the mandibular region and adipose tissue contribute to ageing.
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Ageing in the lower face is characterised by vertical lip stretching, upward oral commissures, and increase in the distance between the columella and vermillion border.
F Horizontal lip stretching, downward oral commissures.
With regards to ageing in the lower face, this is characterised by loss of lip thickness, perioral wrinkles, marionette lines and dimpled or peau d’orange chin.
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The main manifestations of neck ageing are horizontal bands of platysma muscle, as well as vertical wrinkles, deposits of subcutaneous fat, and skin alterations related to photodamage.
F Vertical bands of platysma muscle, horizontal wrinkles.
Platysma bands are determined mainly by muscular hyperkinetic activity and are not treatable by BT-A.
F Are treatable by BT-A.
The muscular effects of BT usually appear from 24-72 hours after injection, reaching a maximum around 2 weeks.
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The muscular effects of BT last 6-9 months.
F 4-6 months.
The anhidrotic effects of BT last 4-6 months.
F 6-9 months.
Repeated treatments with BT-A have been proven to be safe and effective.
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Repeated treatments with BT-A produce cumulative changes to the innervation pattern and cumulative histological changes affecting some muscles more than others.
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Nerve regeneration does not always occur after BT-A injections, therefore chronic denervation and muscular atrophy can persist after repeated BT-A injections.
F Some degree of nerve regeneration always occurs. Chronic denervation and muscular atrophy don’t persist.
Muscular tonus recovery can be allowed in the intervals between injections by selecting the correct dose and respecting the recommended intervals between injections.
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Neurological patients using BT-A are not more prone to develop antibodies.
F Are more prone.