Search PubMed⌕ Search

Biomedical subjects

S Hall

Publications and source records attributed to S Hall.

At least 19 recordsLinked to original sources
PubMed2006

Harmful algal bloom toxins alter c-Fos protein expression in the brain of killifish, Fundulus heteroclitus.

The immediate early gene c-fos, and its protein product c-Fos, are known to be induced in neurons of mammals and fish as a result of neuronal stimulation. The purpose of this study was to quantitatively examine CNS alterations in killifish, Fundulus heteroclitus, in relation to harmful algal bloom (HAB) toxin exposure. c-Fos expression was visualized using immunocytochemistry in the brains of killifish exposed to the excitatory neurotoxins domoic acid (DA) and brevetoxin (PbTx-2), and a paralytic neurotoxin, saxitoxin (STX), released from HABs. In addition, a simulated transport stress experiment was conducted to investigate effects of physical stress on c-Fos induction. Groups of fish were exposed to the different stress agents, brain sections were processed for c-Fos staining, and expression was quantified by brain region. Fish exposed to DA, STX, and transport stress displayed significant alterations in neuronal c-Fos expression when compared to control fish (p< or = 0.05). DA, PbTx-2, and transport stress increased c-Fos expression in the optic tecta regions of the brain, whereas STX significantly decreased expression. This is the first study to quantify c-Fos protein expression in fish exposed to HAB toxins. General alterations in brain activity, as well as knowledge of specific regions within the brain activated in association with HABs or other stressors, provides valuable insights into the neural control of fish behavior as well as sublethal effects of specific stressors in the CNS.

Animals↗
PubMed2006

A measure of food seeking in individuals with Prader-Willi syndrome.

BACKGROUND: Individuals with Prader-Willi syndrome (PWS), a chromosome 15 genetic disorder, often have a significant preoccupation with food and problem behaviour related to food seeking is often prevalent. METHODS: In the present study, we compared how individuals with PWS responded on a survey regarding the acceptability of food in various locations that varied according to degree of appropriateness for human consumption (e.g. food on a plate, food in a garbage can). For a subgroup of participants, we observed how they actually responded when placed in a room with food items placed in the same locations depicted in the survey. In the first part of the study, three groups (25 typically developing individuals, 7 individuals with intellectual disability (ID), and 19 individuals with PWS) responded to a visual survey to determine the degree of acceptability of food items in various locations (e.g. on a table near a hairbrush, on the floor behind a toy box, in a trash can). In the second part of the study, these food items (popcorn, jelly beans) were placed in the 12 locations described above. Nine individuals diagnosed with PWS (deletion type) and three individuals with ID were given some break time in the room for 15 min. The amount of food consumed, the time spent food seeking, and time spent interacting with materials were measured. RESULTS: Results of the survey indicated that the PWS group differed significantly with regard to how they responded on the survey from the typically developing group, but did not differ significantly from the ID group. Results of the food seeking observations indicated that only three individuals with PWS ate a significant number of items. The three individuals did not differ from the rest of the group according to IQ or compulsivity score; however, they had significantly lower body mass index (BMI) scores and were younger than the other participants. CONCLUSIONS: The findings from the survey indicate that individuals with PWS are able to discriminate the appropriateness of eating items in more or less contaminated areas; however, the amount of time spent seeking food and the amount of food covertly consumed appeared to depend more directly on age and BMI.

Adolescent↗
PubMed2005

Bioresorbable glass fibres facilitate peripheral nerve regeneration.

This is a proof of principle report showing that fibres of Bioglass 45S5 can form a biocompatible scaffold to guide regrowing peripheral axons in vivo. We demonstrate that cultured rat Schwann cells and fibroblasts grow on Bioglass fibres in vitro using SEM and immunohistochemistry, and provide qualitative and quantitative evidence of axonal regeneration through a Silastic conduit filled with Bioglass fibres in vivo (across a 0.5 cm interstump gap in the sciatic nerves of adult rats). Axonal regrowth at 4 weeks is indistinguishable from that which occurs across an autograft. Bioglass fibres are not only biocompatible and bioresorbable, which are absolute requirements of successful devices, but are also amenable to bioengineering, and therefore have the potential for use in the most challenging clinical cases, where there are long inter-stump gaps to be bridged.

Absorbable Implants↗
PubMed2005

Improved high-performance liquid chromatographic method for the determination of domoic acid and analogues in shellfish: effect of pH.

Domoic acid (DA) is a naturally-occurring amino acid that causes a form of human intoxication called amnesic shellfish poisoning (ASP) following the consumption of shellfish. A rapid and sensitive HPLC-UV method has been developed for analysis of DA and analogues in shellfish without the need for SPE clean-up. Isocratic chromatographic separation of DA and its isomers from shellfish matrix interferences and from the prevalent amino acid, tryptophan, was achieved by careful control of the mobile phase pH. The optimised pH was found to be 2.5 when using a Luna(2) C18 column. Sample extraction was verified with control extracts from shellfish spiked at 5.0 and 10.0 microg/g of DA and with certified reference material. The average extraction efficiency was 98.5%. The calibration, based on mussel tissue spiked with DA standard, was linear in the range 0.05-5.0 microg/ml (r = 0.9999) and the detection limit (signal:noise 3:1) was better than 25 ng/ml. The DA assay achieved good precision; %RSD = 1.63 (intra-day, n = 6) and %RSD = 3.7 (inter-day, n = 8). This method was successfully applied to a variety of shellfish species, allowing the rapid screening of a large number of samples per day (20-30), without the need for SPE clean-up. Quantitative data were obtained for shellfish samples containing domoic acid in the concentration range 0.25-330 microg/g. Using the same chromatographic conditions, LC-MS3 was used to determine DA and its isomers, isodomoic acid D and epi-domoic acid, in scallop tissues.

Animals↗
PubMed2005

The association between environmental events and self-injurious behaviour in Cornelia de Lange syndrome.

BACKGROUND: There has been limited empirical research into the environmental causes of self-injury in Cornelia de Lange syndrome. The present study examined the variability of self-injurious behaviour in Cornelia de Lange syndrome across environmental setting events. Additionally, the association between setting events and more specific environmental events was examined. METHOD: A descriptive analysis of observational data on eight children with Cornelia de Lange syndrome aged between 4 and 14 years was carried out. The association between self-injurious behaviour and four environmental setting events and between specific environmental events and setting events was examined using established statistical methods for observational data. RESULTS: Seven out of eight of the participants showed at least one form of self-injurious behaviour that was associated with a particular setting event. The study also demonstrated that the relationship between setting events and environmental events is extremely variable across individuals. CONCLUSIONS: Self-injurious behaviour in some individuals with Cornelia de Lange syndrome is associated with environmental events although the precise nature of the association warrants clarification. Using broad setting events as a methodological tool in isolation provides some insight into the role of specific environmental factors in maintaining self-injurious behaviour but the integrity of setting events must be established.

Adolescent↗
PubMed2005

The early development of self-injurious behaviour: evaluating the role of social reinforcement.

BACKGROUND: The potential role of social reinforcement in the development of self-injury has not yet been subjected to empirical analysis. In this 2-year prospective study, the pattern of social interactions related to the early presentation of self-injury were examined to identify a potential association with an increase in self-injury. METHODS: The self-injurious behaviour and social contact with adults of 16 children with intellectual disability (ID) with self-injury of recent onset were observed at 3-month intervals over 2 years. RESULTS: Increase in self-injury over a 2-year period was positively correlated with a distribution of social contact relative to episodes of self-injury that is consistent with a mutual social reinforcement paradigm. When this paradigm was operative, self-injury was evoked under stable antecedent conditions over time but tended to evoke increasing levels of social interaction. CONCLUSIONS: These results support the hypothesis that increases in the frequency of early self-injury in children with ID may be determined by social reinforcement with implications for early intervention and proactive identification of children at risk for increases in self-injury.

Adolescent↗
PubMed2004

Arthrographic joint distension with saline and steroid improves function and reduces pain in patients with painful stiff shoulder: results of a randomised, double blind, placebo controlled trial.

OBJECTIVE: To determine whether arthrographic distension with a mixture of saline and steroid, in patients with painful stiff shoulder for at least 3 months, is better than placebo in improving function, pain, and range of motion at 3, 6, and 12 weeks. METHODS: A randomised, placebo controlled trial with participant and outcome assessor blinding in which shoulder joint distension with normal saline and corticosteroid was compared with placebo (arthrogram). Outcome measures, assessed at 3, 6, and 12 weeks, included a shoulder-specific disability measure (SPADI), a patient preference measure (Problem Elicitation Technique (PET)), pain, and range of active motion. RESULTS: From 96 potential participants, 48 were recruited. Four withdrew from the placebo group after the 3 week assessment and three subsequently received arthrographic distension with saline and steroid. At 3 weeks, significantly greater improvement in SPADI (p = 0.005), PET, overall pain, active total shoulder abduction, and hand behind back was found in participants in the joint distension and steroid group than in the placebo group. At 6 weeks the results of the intention to treat analysis favoured joint distension, although the between-group differences were only significant for improvement in PET (difference in mean change in PET between groups = 45.9 (95% CI 3.2 to 88.7). Excluding the four withdrawals, the between-group differences for the disability and pain measures significantly favoured distension over placebo. At 12 weeks, both the intention to treat analysis and an analysis excluding the four withdrawals demonstrated a significantly greater improvement in PET score for the distension group. CONCLUSIONS: Short term efficacy of arthrographic distension with normal saline and corticosteroid over placebo was demonstrated in patients with painful stiff shoulder.

Anti-Inflammatory Agents↗
PubMed2004

Short course prednisolone for adhesive capsulitis (frozen shoulder or stiff painful shoulder): a randomised, double blind, placebo controlled trial.

OBJECTIVE: To determine whether a short course of prednisolone is superior to placebo for improving pain, function, and range of motion in adhesive capsulitis. DESIGN: Double blind, randomised, placebo controlled trial. SETTING: Community based rheumatology practice in Australia. PARTICIPANTS: 50 participants (24 active, 26 placebo); 46 completed the 12 week protocol. Entry criteria were age > or =18 years, pain and stiffness in predominantly one shoulder for > or =3 weeks, and restriction of passive motion by >30 degrees in two or more planes. INTERVENTIONS: 30 mg oral prednisolone/day for three weeks or placebo. MAIN OUTCOME MEASURES: Overall, night, and activity related pain, SPADI, Croft shoulder disability questionnaire, DASH, HAQ, SF-36, participant rated improvement, and range of active motion measured at baseline and at 3, 6, and 12 weeks. RESULTS: At 3 weeks, there was greater improvement in overall pain in the prednisolone group than in the placebo group (mean (SD) change from baseline, 4.1 (2.3) v 1.4 (2.3); adjusted difference in mean change between the two groups, 2.4 (95% CI, 1.1 to 3.8)). There was also greater improvement in disability, range of active motion, and participant rated improvement (marked or moderate overall improvement in 22/23 v 11/23; RR = 2 (1.3 to 3.1), p = 0.001). At 6 weeks the analysis favoured the prednisolone group for most outcomes but none of the differences was significant. At 12 weeks, the analysis tended to favour the placebo group. CONCLUSIONS: A three week course of 30 mg prednisolone daily is of significant short term benefit in adhesive capsulitis but benefits are not maintained beyond six weeks.

Anti-Inflammatory Agents↗