Botulinum toxin type A outcomes in infants with refractory congenital muscular torticollis.

PURPOSE: The aim of this study was to determine the effectiveness of botulinum toxin type A (BoNT-A) injections in infants with congenital muscular torticollis (CMT) who were refractory to conservative management. METHODS: This was a retrospective study in which all subjects included were seen between 2004 and 2013 and were deemed appropriate for BoNT-A injections. A total of 291 patients were reviewed for inclusion in the study, and 134 patients met the inclusion criteria. Each child was injected with 15-30 units of BoNT-A into each of the following muscles: ipsilateral sternocleidomastoid, upper trapezius, and scalene muscles. The key outcome and variable measurements analyzed included age at time of diagnosis, age at time of initiation of physical therapy, age at time of injection, total number of injection series utilized, muscles injected, and degrees of active and passive cervical rotation and lateral flexion pre- and post-injection. A successful outcome was documented if a child could achieve 45° of active lateral flexion and 80° of active cervical rotation post-injection. Secondary variables including sex, age at time of injection, number of injection series utilized, surgery required, adverse effects of botulinum toxin, presence of plagiocephaly, side of torticollis, orthosis used, presence of hip dysplasia, skeletal anomalies, complications during pregnancy or birth, and any other pertinent information regarding the delivery were also measured. RESULTS: Based on this criteria, 82 children (61%) had successful outcomes. However, only four of the 134 patients required surgical correction. CONCLUSION: BoNT-A may be an effective and safe method for treatment in refractory cases of congenital muscular torticollis.

Reduced oxygen tension culturing conditionally alters toxicogenic response of differentiated H9c2 cardiomyoblasts to acrolein.

Acrolein is a reactive electrophilic aldehyde known to cause mitochondrial dysfunction, oxidative stress, and dysregulation of signaling transduction in vitro. Most in vitro systems employ standard cell culture maintenance conditions of 95% air/5% CO2, translating to a culture oxygen tension of approximately 20%, far above most physiological tissues. The purpose of this investigation was to examine whether low-serum, retinoic acid differentiated H9c2 cells were less sensitive to acrolein insult when cultured under reduced oxygen tension. H9c2 cells were maintained separately in 20% and 5% oxygen, differentiated for 5 d, and then exposed to acrolein for 30 min in media containing varying concentrations of tricarboxylic acid and glycolytic substrates, followed by fresh medium replacement. Cells were then assessed for MTT reduction at 2 h and 24 h after acrolein insult. We showed that pyruvate supplementation in combination with lowered oxygen culturing significantly attenuated acrolein-induced viability loss at 24 h. Poly(ADP-ribose) polymerase inhibition and EGTA preferentially provided partial rescue to low oxygen cultures, but not for standard cultures. Collectively, these results offer evidence supporting altered toxicogenic response of H9c2 during physiologically relevant oxygen tension culturing.

Acrolein measurement and degradation in Dulbecco's Modified Eagle Medium: an examination of in-vitro exposure metrics.

Acrolein is a reactive α,ß-unsaturated aldehyde known for its adduction to endogenous biomolecules, resulting in initiation or exacerbation of several disease pathways. In-vitro systems are routinely used to elucidate the cytotoxic or mechanistic role(s) of acrolein in pathogenesis. Nevertheless, the half-life of acrolein in biological or in-vitro systems, e.g. blood or culture media, has not been well characterized. Since in-vitro cytotoxic and mechanistic investigations routinely expose cultures to acrolein from 1 hour to 72 hours, we aimed to characterize the half-life of acrolein in culture medium to ascertain the plausible exposure window. Half-life determinations were conducted in low-serum DMEM at room temperature and 37 °C, both with and without H9c2 cells. For quantitative assessment, acrolein was derivatized to a fluorescent 7-hydroxyquinoline method validated in-house and assessed via fluorescent spectroscopy. In closed vessel experiments at room temperature, acrolein in DMEM was reduced by more than 40% at 24 hours, irrespective of the initial concentration. Expectedly, open vessel experiments demonstrated accelerated depletion over time at room temperature, and faster still at 37 °C. The presence of cells tended to further accelerate degradation by an additional 15-30%, depending on temperature. These results undermine described experimental exposure conditions stated in most in-vitro experiments. Recognition of this discrepancy between stated and actual exposure metrics warrant examination of novel alternative objective and representative exposure characterization for in-vitro studies to facilitate translation to in-vivo and in-silico methods.

Improvement in survival and muscle function in an mdx/utrn(-/-) double mutant mouse using a human retinal dystrophin transgene.

Duchenne muscular dystrophy is a progressive muscle disease characterized by increasing muscle weakness and death by the third decade. mdx mice exhibit the underlying muscle disease but appear physically normal with ordinary lifespans, possibly due to compensatory expression of utrophin. In contrast, double mutant mice (mdx/utrn(-/-)), deficient for both dystrophin and utrophin die by approximately 3 months and suffer from severe muscle weakness, growth retardation, and severe spinal curvature. The capacity of human retinal dystrophin (Dp260) to compensate for the missing 427 kDa muscle dystrophin was tested in mdx/utrn(-/-) mice. Functional outcomes were assessed by histology, EMG, MRI, mobility, weight and longevity. MCK-driven transgenic expression of Dp260 in mdx/utrn(-/-) mice converts their disease course from a severe, lethal muscular dystrophy to a viable, mild myopathic phenotype. This finding is relevant to the design of exon-skipping therapeutic strategies since Dp260 lacks dystrophin exons 1-29.