Jennifer A. Thompson

The effects of multidisciplinary rehabilitation in patients with early-to-middle-stage Huntington's disease: a pilot study

Despite advances in the understanding of Huntingtons disease (HD), treatment remains symptomatic. Multidisciplinary rehabilitation, however, appears to impact disease progression. Here we show the feasibility, safety and efficacy of a 9‐month multidisciplinary rehabilitation programme in a small cohort of patients with early‐to‐middle‐stage HD.

Pax genes during neural development and their potential role in neuroregeneration

Pax genes encode a family of transcription factors that have long been recognised as obligate contributors to embryonic development of the CNS, with evidence obtained from various animal models illustrating phylogenetically conserved functions. Within the CNS, Pax genes play substantial roles in cellular and regional specification, proliferation, progenitor cell maintenance, anti-apoptosis and neural differentiation. This comprehensive review details the critical functions of those Pax genes involved in pre- and post-natal CNS development, provides possible molecular mechanisms by which Pax genes contribute to proliferation and differentiation of neuronal cells, and explains observed changes in Pax gene expression in response to neurotrauma in the mature animal. Knowledge of the ability of individual Pax genes to specify precise lineages within the CNS is beneficial for cell replacement strategies, particularly in the production of designer cells for the treatment of neurodegenerative disorders. The manipulation of stem or committed cells so that they express definitive Pax genes may indeed assist in the pursuit of the holy grail of regenerative medicine - that of CNS cell replacement therapies leading to functional repair. We explain here, however, that only the sophisticated and precise use of Pax genes will lead to a successful outcome.

Perplexing Pax: From Puzzle to Paradigm

Pax transcription factors are critical for the development of the central nervous system (CNS) where they have a biphasic role, initially dictating CNS regionalization, while later orchestrating differentiation of specific cell subtypes. While a plethora of expression, misexpression, and mutation studies lend support for this argument and clarify the importance of Pax genes in CNS development, less well understood, and more perplexing, is the continued Pax expression in the adult CNS. In this article we explore the mechanism of action of Pax genes in general, and while being cognizant of existing developmental data, we also draw evidence from (1) adult progenitor cells involved in regeneration and tissue maintenance, (2) specific expression patterns in fully differentiated adult cells, and (3) analysis of direct target genes functioning downstream of Pax proteins. From this, we present a more encompassing theory that Pax genes are key regulators of a cells measured response to a dynamic environment. Developmental Dynamics 237:2791–2803, 2008.

Inhaled methoxyflurane and intranasal fentanyl for prehospital management of visceral pain in an Australian ambulance service

Objective This study analysed the analgesic effect and changes in vital signs associated with administration of inhaled Methoxyflurane (MTX) and/or intranasal Fentanyl (INF) for prehospital management of visceral pain. Method A retrospective, observational study reviewing 1024 randomly selected records of patients with presumed visceral pain administered MTX (465), INF (397) or both (162) by the Western Australian Ambulance Service between January 2004 and February 2006. Clinical variables assessed included systolic blood pressure, pulse rate, respiration rate and Glasgow Coma Scale score. Pain was assessed utilising Visual/Verbal Analogue Scale pain scores. Results Overall effects on vital signs appeared favourable 5u2005min after use and at hospital arrival with either agent alone or in combination. As sole agents, MTX produced the greatest initial pain scores reduction (2.0 (1.7 to 2.2) vs 1.6 (1.4 to 1.8)) (mean (95% CI), and INF provided greater pain reduction by hospital arrival (3.2 (2.9 to 3.5) vs 2.5 (2.1 to 2.9)). While both agents were effective, INF provided a greater pain score reduction for cardiac (3.0 (2.6 to 3.4) vs 2.3 (1.8 to 2.8)), female (3.4 (2.9 to 4.0) v 2.5 (2.0 to 3.0)) and age 75+ patients (3.2 (2.5 to 3.8) vs 1.8 (1.0 to 2.5)). Combined use of agents was not advantageous. Conclusions MTX and INF are effective agents for providing visceral pain analgesia in the prehospital setting. While MTX provided a more rapid onset of pain relief, INF provided superior analgesia after subsequent doses and in female, cardiac and older patients.

The effect of multidisciplinary rehabilitation on brain structure and cognition in Huntington's disease: An exploratory study

There is a wealth of evidence detailing gray matter degeneration and loss of cognitive function over time in individuals with Huntingtons disease (HD). Efforts to attenuate disease‐related brain and cognitive changes have been unsuccessful to date. Multidisciplinary rehabilitation, comprising motor and cognitive intervention, has been shown to positively impact on functional capacity, depression, quality of life and some aspects of cognition in individuals with HD. This exploratory study aimed to evaluate, for the first time, whether multidisciplinary rehabilitation can slow further deterioration of disease‐related brain changes and related cognitive deficits in individuals with manifest HD.

Pax7 is requisite for maintenance of a subpopulation of superior collicular neurons and shows a diverging expression pattern to Pax3 during superior collicular development

BackgroundPax7 encodes a transcription factor well-established as an important determinant of mesencephalic identity and superior collicular development. Pax7 mutant mice, however, present with no obvious morphological impairments to the superior colliculus. This finding is paradoxical and has been attributed to functional redundancy afforded by its paralogue Pax3. Here we utilise Pax7 mutant mice to investigate the precise role of this important developmental regulator during superior collicular development and neuronal specification/differentiation. We also assess its spatiotemporal relationship with Pax3 during embryonic development.ResultsAnalysis of the superior colliculus of Pax7 mutant and wildtype mice at a variety of developmental timepoints revealed that whilst correct initial specification is maintained, a subpopulation of dorsal mesencephalic neurons is lost at early postnatal stages. Moreover, a comparative analysis of embryonic Pax3 and Pax7 expression profiles indicate that Pax3 expression overlaps extensively with that of Pax7 initially, but their expression domains increasingly diverge as development progresses, coinciding spatiotemporally with neuronal differentiation and maturation of the tissue. Furthermore, Pax3 expression is perturbed within the CNS of embryonic Pax7 mutant mice.ConclusionIn summary, these results demonstrate that during superior collicular development, Pax7 is required to maintain a subpopulation of dorsal, mesencephalic neurons and partially regulates, spatiotemporally, Pax3 expression within the CNS. The differential nature of Pax7 and Pax3 with respect to neuronal differentiation may have implications for future stem cell therapies aimed at exploiting their developmental capabilities.

The role of Pax7 in determining the cytoarchitecture of the superior colliculus

Pax genes are a family of transcriptional regulators vital for embryonic development. One member of the family, Pax7, functions early in neural development to establish dorsal polarity of the neural tube, and continuous refinement of its expression affords regional identity to brain nuclei, in particular the superior colliculus. Pax7 expression within the superior colliculus is eventually restricted to the stratum griseum et fibrosum superficiale (SGFS), the retinorecipient layer to which the optic nerve projects. The key role of Pax7 in specification of the superior colliculus has been highlighted by misexpression studies which result in ectopic formation of superior collicular tissue with characteristic laminae innervated by retinal ganglion cell axons. Here we review the role of Pax7 in formation of the superior colliculus and discuss the possibility that Pax7 may also assist in refinement of correct topographic mapping.

Pax7 and superior collicular polarity: insights from Pax6 (Sey) mutant mice

Pax genes are important modulators of CNS development. Pax7 and Pax6 polarise the neural tube and regionalise the brain. Pax7 is pivotal in specifying the superior colliculus/tectum, an important centre for integration of visuomotor responses and a target for Pax6+ retinal ganglion cell axons during retinocollicular mapping. Whilst initial Pax7-specification of the mesencephalon is well-established, a role in regulating polarity within the maturing mouse superior colliculus is yet to be defined, although already detailed for the chick tectum. We therefore quantified Pax7 cellular distribution and expression levels at three functionally distinct stages of superior collicular development, and analysed Pax7 expression in response to aberrant axonal input and altered forebrain/midbrain boundary placement in Pax6 mutant mice. Comparative expression profiles of ephrin-A2 and its co-localisation with Pax7 were determined in wildtype and Pax6 mutant mice. Results indicate that graded Pax7 expression in wildtype mice is perturbed in Pax6 mutant mice; changes manifest as a shift in polarity, loss of graded expression and dramatically reduced protein levels during RGC synaptogenesis. Ephrin-A2 expression is similarly altered. These results implicate Pax7 as an important determinant of polarity within the mouse superior colliculus, and suggest a role in retinotopic mapping.

Surface electromyograph activity of submental muscles during swallowing and expiratory muscle training tasks in Huntington's disease patients

INTRODUCTIONnHuntingtons disease (HD) patients have difficulty in swallowing, leading to aspiration pneumonia, which is a major cause of death. It seems possible that submental muscles that are crucial for preventing an escape of a bolus into the airway, are affected by HD, but no previous studies have investigated this.nnnOBJECTIVEnTo assess surface electromyograph (sEMG) activity of submental muscles during swallowing and expiratory muscle training (EMT) tasks in HD patients in comparison to healthy volunteers.nnnMETHODSnsEMG activities of submental muscles during saliva, water swallowing, EMT tasks performed at 25% and 75% of maximum expiratory pressure were recorded and normalised by the sEMG activity during an effortful swallow in 17 early to mid stage HD patients and 17 healthy volunteers.nnnRESULTSnsEMG activity was greater (p<0.05) during EMT tasks than saliva and water swallowing, but was not significantly different between groups for saliva, water swallowing and EMT at 25%. HD patients had lower sEMG activity for EMT at 75% (p<0.05).nnnCONCLUSIONnDecreases in submental muscle activity were not evident in HD patients except during EMT at 75%. This suggests that relative submental muscle weakness is observed only during a high intensity task in early to mid stage HD patients.

Effects of multidisciplinary therapy on physical function in Huntington's disease

The primary objective of this trial was to evaluate the effects of outpatient multidisciplinary therapy, compared to usual care, on measures of physical function and muscle strength in patients with manifest Huntingtons disease (HD).