Aging affects coordination of rapid head motions with trunk and pelvis movements during standing and walking

The head, containing the gravity sensors (vestibular system) and the visual system, must be stabilized in space to provide a steady reference. During walking, the head also needs to be free to move to allow scanning of surrounding objects and steering of locomotion. With aging, deteriorations in motor and sensory systems and their integration are commonly observed. Nevertheless, the strategies used by elderly subjects to complete challenging tasks that require precise sensorimotor integration, such as turning the head rapidly during gait, is not known. The objective of this study was to determine the effects of aging on the movement coordination of the head, trunk and pelvis when executing a rapid head motion in response to a visual signal. Elderly and young subjects turned their head rapidly (up, down, left, right or none) in response to a visual signal, during standing and walking. The 3-D positions of head, trunk and pelvis were recorded and analyzed. All subjects, young and old, successfully performed the task during both standing and walking without any loss of balance. Postural stability was maintained as large head motions were accompanied by relatively small trunk and pelvis movements. Horizontal plane movements associated with right and left head turns were significantly larger than sagittal plane movements associated with head up and down motions. Head motions were significantly slower and smaller in elderly subjects, and resulted in disrupted horizontal plane trunk-pelvis coordination during walking. We conclude that head, trunk and pelvis movements are coordinated in a task-dependent manner such that their movement amplitudes induced by rapid voluntary head motions are larger in walking than in standing. This task-dependent movement coordination is affected by aging.     

Polymorphisms of the cholesterol 24-hydroxylase (CYP46A1) gene and the risk of Alzheimer's disease in a Chinese population

BACKGROUND: An increasing number of studies have suggested a link between cholesterol metabolism and Alzheimer's disease (AD), which may be mediated by its effect on amyloid processing. Intracranial cholesterol is primarily eliminated into the bloodstream through conversion into 24-hydroxycholesterol by the enzyme cholesterol 24-hydroxylase (encoded by the CYP46A1 gene). CYP46A1 is an essential gene modulating cholesterol metabolism in the brain. METHOD: To investigate whether polymorphisms in the CYP46A1 gene modulate the risk of AD, we studied four common polymorphisms (IVS1-192, IVS2-150, IVS3-128 and IVS4-122) in 182 Chinese AD patients and 179 age-matched healthy Chinese subjects. RESULTS AND CONCLUSION: We found that the IVS3-128 polymorphism was associated with the risk of AD (p < 0.05). Subjects homozygous for the C alleles were protected from AD with an adjusted odds ratio (OR) of 1.53 [95% confidence interval (95% CI) 0.98-2.37, p = 0.047]. However, another minor allele, IVS1-192 C, was more prevalent in the AD group and was associated with an increased risk. Haplotype analysis revealed that two of the eight common haplotypes formed by the four polymorphisms were rarely found in the AD group, suggesting a protective effect of these two haplotypes (GTCA and CCTA). The results supported the involvement of the CYP46A1 gene and cholesterol metabolism in the pathogenesis of AD.     

9The TANTALUSTM System for obesity: effect on gastric emptying of solids

Background: Gastric electrical stimulation (GES) is currently investigated for the treatment of obesity. The TANTALUS System delivers gastric contractility modulation (GCM) signals in synchrony with gastric slow waves, resulting in significant augmentation of gastric contractions during food intake. We hypothesized that such modulation of contractile activity may affect gastric emptying and plasma ghrelin levels. Aim: To test the effect of GCM of the gastric antrum on gastric emptying of solids and ghrelin levels. Methods: 12 obese subjects were implanted with 2 pairs of antral electrodes and an implantable pulse generator (IPG, TANTALUS ^TM) Gastric emptying test (GE) for solids was performed twice, on separate days, in each subject, starting few weeks after implantation: 1) control, before the start of stimulation, and 2) with stimulation, after device was turned on. Blood samples for ghrelin, were taken at baseline, and at 15, 30, 60 and 120 min after the test meal. Results as mean + SD, analysis by t‐test and p < 0.05. Results: 11 females, 1 male, age: 39.1 ± 8.9 years, BMI: 41.6 ± 3.4, 3 subjects with type 2 diabetes. One diabetic patient did not complete GE test because of technical issues. GCM significantly accelerated gastric emptying: retention at 2 hours 18.7 ± 12.2% vs. 31.9 ± 16.4%, stimulation vs. control respectively, p = 0.008. T ^1/2 78.3 ± 23.5 vs. 95 ± 31.7 min, stimulation vs. control respectively, p = 0.04. Mean results for gastric emptying were within normal at both baseline and stimulation. Meal ingestion induced only minimal, insignificant reduction in ghrelin levels. There was no significant difference in AUC of ghrelin between control and stimulation. Conclusions: After GCM stimulation, there is significant acceleration of gastric emptying of solids in obese patients, without affect on ghrelin levels. The obese subjects did not exhibit the significant, meal‐induced reduction in ghrelin.      

Use of computed tomography in the setting of a tiered trauma team activation system in Australia

This study aims to describe the patterns in the use of computed tomography (CT) imaging in the setting of a two-tiered trauma team activation system without a mandatory whole-body (“panscan”) trauma CT protocol. A prospective study was conducted at a single inner city major trauma centre in Sydney, Australia. Adult patients presenting to the emergency department requiring a trauma team activation were studied over 1 year. Patients in the trauma consult group met predetermined criteria for mechanism of injury without vital sign abnormalities or clinical evidence of major injury. Full trauma team response patients were those who had abnormal predetermined vital signs or evidence of major injury on initial assessment. The outcomes measured were severe injury, multiregion injury and positive CT scans. Of the patients, 1,058 were studied of whom 63 % had at least one CT scan performed. The most common CT studies were CT brain in combination with cervical spines (23 %) and isolated abdominal CT scans (17 %). The full trauma response group was associated with significantly higher rates of severe injury (34 versus 8 %, p?<?0.001), multiregion injury (13 versus 3 %, p?<?0.001), need for operative intervention (37 versus 15 %, p?<?0.001) and in-hospital mortality (4 versus 0.7 %, p?<?0.001). This group was also associated with significantly higher odds of whole-body CT use [odds ratio (OR) 5.6, 95 % confidence interval (CI) 3.6–8.8, p?<?0.001] and higher odds of positive CT brain studies compared to the trauma consult group (OR 2.6, 95 % CI 1.7–4.1, p?<?0.001). A tiered trauma team activation criteria in combination with trauma team assessment may be used to triage patients requiring CT without the need for mandatory CT protocols based on mechanism alone.     

Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systems was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time.     

Correlative study of pain perception and masticatory muscle reflexes in man.

An attempt was made to explore the possibility of using the masticatory muscle reflexes as pain indices in human subjects. It was found that the digastric reflex, so readily evoked by electrodental stimulation in experimental animals, could not be consistently elicited in man. The reflex silent period of the masseteric muscles, on the other hand, may be used as a pain index for evaluating dental analgesia, provided that analgesic interference is anticipated at points along the reflex arc.     

Factors affecting outcomes of traumatically extruded permanent teeth in children

PURPOSE: The objectives of the present study were to determine the prevalence of residual extrusion, pulpal necrosis, and resorption for extruded permanent teeth and to establish the effect of presentation and treatment factors. METHODS: Seventy-two traumatically extruded permanent incisors were studied at the Departments of Paediatric Dentistry in Belfast, Newcastle upon Tyne, and Glasgow. The mean age of the patients was 10.1 years (range=6 to 18 years). Clinical and radiographic outcomes were analyzed and related to presenting and treatment factors. RESULTS: The initial degree of extrusion was moderate for 46 teeth (64%), and the median delay prior to repositioning was 3 hours (range=1 to 168 hours). Pulp necrosis occurred in 31 teeth (43%), residual extrusion was present in 16 teeth (23%), and inflammatory resorption occurred in 11 teeth (15%). Residual extrusion was significantly associated with a delay in repositioning the tooth, pulpal necrosis was significantly more common in teeth with closed apices and in severely extruded teeth, and inflammatory resorption was more common after pulpal necrosis. CONCLUSIONS: Residual extrusion could be minimized by earlier presentation and repositioning. The risk of pulpal necrosis is greatest for severely extruded teeth and for those with closed apices.