Biomedical subjects

R R Sloop

Publications and source records attributed to R R Sloop.

4 recordsLinked to original sources

PubMed2001

Muscle paralysis produced by botulinum toxin type A injection in treated torticollis patients compared with toxin naive individuals.

We sought to determine whether the response to varying doses of botulinum toxin type A (BTX-A) injected in BTX-A-treated torticollis patients differed from the same injections given in toxin-naive individuals. We have developed a technique to objectively measure muscle weakness resulting from BTX injections in humans and have validated the technique in those not previously treated with BTX. We now examine BTX-A-treated torticollis patients to see if their response to BTX-A injection is similar to that of toxin-naive individuals. We injected 11 torticollis patients who had been receiving BTX-A injections with a standard 5-mouse unit (mu) dose into one extensor digitorum brevis (EDB) muscle and a varying dose into the other EDB, measuring muscle paralysis 2 weeks after the injection. Nine of the 11 patients were clinical and electrophysiologic responders. Two patients were non-responders. In the 9 responding patients the dose response curve to increasing doses of BTX-A was very similar to that seen in toxin-naive individuals. The mean muscle paralysis from the standard 5 mu dose was also similar to that previously reported in toxin-naive individuals. Torticollis patients who continue to respond clinically to BTX-A injections demonstrate essentially the same degree of muscle paralysis from the EDB injections as do subjects who have never been exposed to BTX-A.

Adult↗

PubMed1997

Reconstituted botulinum toxin type A does not lose potency in humans if it is refrozen or refrigerated for 2 weeks before use.

Botulinum toxin type A (BTX-A) (Botox, Allergan, Irvine, CA) labeling recommends its use within 4 hours of reconstitution. Since BTX-A is available only in 100-unit vials, a substantial quantity is often discarded. Using eight volunteers, we measured the percent decline in extensor digitorum brevis (EDB) M-wave amplitude (percent paralysis) following injection of freshly reconstituted BTX (right EDB) and compared this with the decline following injection of BTX that was refrozen (-20 degrees C) or refrigerated (+4 degrees C) for 2 weeks (left EDB) after reconstitution. When analyzed as paired data, there was essentially no difference in the muscle paralysis resulting from fresh BTX compared with refrozen or refrigerated BTX, and no statistical difference between groups was noted. Reconstituted BTX-A that is subsequently refrigerated or refrozen for 2 weeks does not lose potency in humans.

Adult↗

PubMed1997

Human response to botulinum toxin injection: type B compared with type A.

Despite the clinical potential of botulinum toxin type B (BTXB) for treating focal dystonia, hemifacial spasm, and other movement disorders, particularly in those resistant to botulinum toxin type A (BTXA), no objective human data exist to compare the muscle paralysis resulting from these two botulinum toxin subtypes. To objectively compare the human muscle paralysis resulting from intramuscular injections of BTXB with that from BTXA, we measured the extensor digitorum brevis (EDB) M wave amplitude four times before and six times after injection with 17 different doses of BTXB (from 1.25 to 480 units) in 17 healthy volunteers. This established a dose-response curve that we compared with the previously published BTXA dose-response curve. After the establishment of the dose-response curve, we injected 10 new volunteers with five different doses of BTXB and BTXA measuring EDB M wave amplitude 4 times before and 13 times over 57 weeks after injection. The volunteers were randomized by dose and received BTXA and BTXB in opposite EDB muscles. The effect of the toxin in all volunteers was expressed as percent decline in M wave amplitude postinjection (% paralysis). The maximal paralysis 2 weeks postinjection with 320 to 480 mouse units (MU) of BTXB was 50 to 75%, whereas maximal paralysis was 70 to 80% with 7.5 to 10 MU of BTXA. Postexercise M wave facilitation on day 9 postinjection averaged 63% for BTXB and 20% for BTXA. Seven weeks postinjection, BTXB-induced paralysis had improved by 66% with complete improvement by 11 weeks postinjection, whereas BTXA-induced paralysis had improved by only 6% at 7 weeks, and at 57 weeks postinjection 22% of the original muscle paralysis was still present. Thus, human muscle paralysis resulting from BTXB injection is not as complete or long-lasting as that resulting from BTXA.

Botulinum Toxins↗

PubMed1996

Dose-response curve of human extensor digitorum brevis muscle function to intramuscularly injected botulinum toxin type A.

To develop a human model for measuring the effect of intramuscularly injected botulinum toxin, we injected both extensor digitorum brevis (EDB) muscles in 13 healthy volunteers with seven varying doses of botulinum toxin type A. We measured, pre- and postinjection, EDB M-wave amplitude, area, and mean rectified voltage (MRV) (obtained during maximal voluntary muscle activation). There was a logarithmic-appearing dose-response relationship between increasing doses of botulinum toxin and decline in EDB M-wave amplitude, area, and MRV. The decline was incrementally less at higher doses of toxin and appeared to level off at a maximal effect of 85 to 90% decrement from baseline (85 to 90% "paralysis") at 15 to 20 units. The peak toxin effect was present on day 6 postinjection. Measurement of EDB M-wave amplitude, area, and MRV is a simple objective method for quantifying the onset and degree of human muscle "paralysis" following botulinum-toxin injection.

Adult↗