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G Allen

Publications and source records attributed to G Allen.

At least 19 recordsLinked to original sources
PubMed2006

The effect of local anaesthetic cream (EMLA) applied with an occlusive dressing on skin thickness. Does it matter?

EMLA cream is used in plastic surgery as a topical anaesthetic to harvest split skin grafts. It has been observed that the skin appears pale and oedematous after the application of EMLA. The aim our study was to determine the effect of EMLA with an occlusive dressing on skin thickness using a high frequency ultrasound. Twenty volunteers took part in this study after approval from the ethics committee. An area of skin was marked on both thighs and the skin thickness of each, measured using ultrasound. EMLA with an occlusive dressing was applied to one thigh. This was removed after at least 2 h of application time but at different time points and skin thickness of each thigh measured again. Data was analysed using t-test and Pearson's correlation. Mean age in years +/- SD (range) was 36.1 +/- 12.1 (23 - 61). Male:female ratio was 8:12. Mean skin thickness +/- SEM increased from 1.86 +/- 0.055 mm prior to EMLA application to 1.96 +/- 0.051 mm post-EMLA application p= 0.02. There was a significant correlation between the increase in skin thickness and duration of application of EMLA cream (p = <0.001, R2 = 0.59). The results conclude that EMLA applied under an occlusive dressing has an effect on skin tissue thickness and any surgeon who harvests split skin grafts under EMLA should be aware of this. Further research is needed to compare laser treatments performed under local anaesthetic creams against general anaesthesia as an increase in skin thickness may affect the depth of laser penetration.

Adult↗
PubMed2006

Anesthetic management of the pregnant patient for endovascular coiling of an unruptured intracranial aneurysm.

Diagnosis of an intracranial aneurysm during pregnancy is a rare event requiring multidisciplinary care for successful management. The knowledge base for the anesthesiologist involves principles of both obstetric and neuroanesthesia, as well as critical care. This article reports such a case and discusses the relevant pathophysiology, along with details of the perioperative management by the anesthesiology team.

Adult↗
PubMed2005

A total score for the CERAD neuropsychological battery.

OBJECTIVE: To develop a total or composite score for the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery. METHOD: CERAD total scores were obtained by summing scores from the individual CERAD subtests (excluding the Mini-Mental State Examination [MMSE]) into a total composite (maximum score = 100). The method of tabulating the total score was constructed using normal controls (NCs; n = 424) and patients with AD (n = 835) from the CERAD registry database. The utility of the total score was further tested in independent samples of mild AD (n = 95), mild cognitive impairment (MCI; n = 60), and NC (n = 95) subjects. RESULTS: The CERAD total score was highly accurate in differentiating NC and AD subjects in the CERAD registry. Age, gender, and education effects were observed, and demographic correction scores were derived through multiple regression analysis. Demographically corrected CERAD total scores showed excellent test-retest reliability across samples (r = 0.95) and were highly correlated with the MMSE (r = 0.89) and Clinical Dementia Rating Scale (r = -0.83) in mixed AD and NC samples and with the Blessed Dementia Rating Scale in an AD sample (r = -0.40). The CERAD total score was highly accurate in differentiating independent samples of NC, MCI, and AD subjects. CONCLUSION: Results provide support for the validity of a Consortium to Establish a Registry for Alzheimer's Disease (CERAD) total score that can be used along with the normative data to provide an index of overall level of cognitive functioning from the CERAD neuropsychological battery.

Age Factors↗
PubMed2005

[Paediatric musculoskeletal ultrasound].

Ultrasound examination is often the most effective and sometimes the only practical means of examining children with soft tissue, tendon and joint diseases. This review will cover the important application of diagnostic ultrasound in children musculoskeletal disorders. We will consider topics where ultrasound is the only sensible means of examination such as developmental dysplasia of the hip, where it is the best choice of several possible methods such as painful hip and when it provides an alternative or adjunct to other imaging such as the examination of soft tissue masses.

Child↗
PubMed2005

Evaluation of chromogenic media for the detection of Listeria species in food.

AIMS: The aim of this study was to evaluate the performance of chromogenic agars, Agar Listeria according to Ottaviani and Agosti (ALOA) and Rapid L. mono agar, compared with Oxford agar for the enumeration and detection of Listeria species in food. METHODS AND RESULTS: A total of 170 food samples were examined using the three plating media. Listeria species were isolated from 63 samples. In contrast to Oxford agar, detection of Listeria colonies on chromogenic media was as good after 24 h of incubation of plates as after 48 h. While there was no significant difference in recovery of Listeria monocytogenes on the three media, recovery of other Listeria species was significantly poorer on Rapid L. mono agar compared with Oxford and ALOA agars. Recovery of species other than L. monocytogenes was significantly improved by including a secondary enrichment stage in the detection method. CONCLUSIONS: Using chromogenic agars, presumptive identification of L. monocytogenes is possible after 24 h, compared with 3-4 days using Oxford agar. However, the poor detection of species other than L. monocytogenes on Rapid L. mono agar is a disadvantage of this medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides new information regarding the isolation of Listeria species other than L. monocytogenes from food using chromogenic plating media. This is important, as non-pathogenic Listeria species act as markers for the likelihood of presence of L. monocytogenes and allow preventive action to be taken to avoid its presence.

Agar↗
PubMed2005

Prevalence of Campylobacter, Salmonella, and Escherichia coli on the external packaging of raw meat.

During September and October 2002, 3,662 prepackaged raw meat samples were collected to evaluate the extent and nature of microbiological contamination on external surfaces of the packaging, which could potentially cross-contaminate ready-to-eat foods during and after purchase. Salmonella was detected on two (<1%) samples of external packaging (both from raw chicken), and Campylobacter was detected on 41 (1.1%) samples of external packaging. The external packaging of game fowl exhibited the highest Campylobacter contamination (3.6%), followed by raw chicken (3.0%), lamb (1.6%), turkey (0.8%), pork (0.2%), and beef (0.1%); Campylobacter jejuni and Campylobacter coli accounted for 59% (24 of 41) and 24% (10 of 41) of the contaminating Campylobacter species, respectively. C. coli isolates from the external packaging were more multiresistant to antimicrobial drugs, including quinolones such as ciprofloxacin, than was C. jejuni. Escherichia coli (an indicator of fecal contamination) was isolated from the external packaging on 4% of the raw meat samples at levels of 40 to 10(5) CFU per swab. The external packaging of raw meats is a vehicle for potential cross-contamination by Campylobacter, Salmonella, and E. coli in retail premises and consumers' homes. The external surface of heat-sealed packaging was less frequently contaminated with Campylobacter and E. coli compared with other types of packaging (e.g., overwrapping, bag, and tie tape) (P < 0.0001 to 0.01). In addition, external packaging of raw meats was contaminated less frequently with Campylobacter and E. coli when packaging was intact, packaging and display areas were visually clean, display temperatures were below 8 degrees C, and hazard analysis systems were in place.

Animals↗
PubMed2004

Imaging features of intraosseous ganglia: a report of 45 cases.

The aim of this study is to report the spectrum of imaging findings of intraosseous ganglia (IG) with particular emphasis on the radiographic and magnetic resonance (MR) features. Forty-five patients with a final diagnosis of IG were referred to a specialist orthopaedic oncology service with the presumptive diagnosis of either a primary or secondary bone tumour. The diagnosis was established by histology in 25 cases. In the remainder, the imaging features were considered characteristic and the lesion was stable on follow-up radiographic examination. Radiographs were available for retrospective review in all cases and MR imaging in 29. There was a minor male preponderance with a wide adult age range. Three quarters were found in relation to the weight-bearing long bones of the lower limb, particularly round the knee. On radiographs all were juxta-articular and osteolytic; 74% were eccentric in location, 80% had a sclerotic endosteal margin and 60% of cases showed a degree of trabeculation. Periosteal new bone formation and matrix mineralization were not present. Of the 29 cases that underwent MR imaging, 66% were multiloculated. On T1-weighted images the IG contents were isointense or mildly hypointense in 90% cases. Forty-one per cent of the cases showed a slightly hyperintense rim lining that enhanced with a gadolinium chelate. Thirty-eight per cent were associated with soft tissue extension and 17% with a defect of the adjacent articular cortex. Fifty-five per cent showed surrounding marrow oedema on T2-weighted or STIR images and two cases (7%) a fluid-fluid level prior to any surgical intervention. The authors contend that it is semantics to differentiate between an IG and a degenerate subchondral cyst as, while the initial pathogenesis may vary, the histological endpoint is identical, as are the imaging features apart from the degree of associated degenerative joint disease. IGs, particularly when large, may be mistaken for a bone tumour. Correlation of the typical radiographic and MR imaging features will indicate the correct diagnosis and obviate the need for biopsy.

Adult↗
PubMed2004

Glutamate-evoked release of adenosine and regulation of peripheral nociception.

Glutamate (which facilitates peripheral nociception) releases adenosine (which inhibits peripheral nociception via adenosine A(1) receptors) when injected locally into the rat hindpaw. The present study determined whether this locally released adenosine could modulate spontaneous pain behaviors produced by a local injection of 1.5% formalin, by determining the effect of 8-cyclopentyl-theophylline (CPT; selective adenosine A(1) receptor antagonist) on flinching produced by formalin/glutamate combinations. Experiments were performed following a prior conditioning injection of 2.5% formalin into the contralateral hindpaw 3-4 days earlier. CPT augmented flinching behaviors produced by 1.5% formalin/1 micromol glutamate, but had no effect on behaviors produced by formalin or glutamate alone. CPT also augmented flinches generated by formalin/alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and formalin/kainic acid, but not by formalin/N-methyl-D-aspartate (NMDA) combinations. The conditioning leads to a clearer expression of the peripheral inhibitory effect of adenosine (inhibitory effect of an inhibitor of adenosine kinase on flinching also was observed), rather than an increased release of adenosine (no enhanced release observed by microdialysis). Microglia appear to be involved in the conditioning, as microglia are activated in the dorsal spinal cord 3 days following injection of 2.5% formalin, and augmentation of formalin/glutamate-induced flinching by CPT is inhibited by the glial metabolic inhibitor fluorocitrate. The augmentation of flinching by CPT is also eliminated following a spinal pretreatment with MK-801 (NMDA receptor antagonist), cyclohexyladenosine (adenosine A(1) receptor agonist), N(G)-nitro-L-arginine methyl ester HCl (nitric oxide synthetase inhibitor), and chelerythrine (protein kinase C inhibitor). The conditioning pretreatment with 2.5% formalin does not lead to a generalized chemical or thermal hypersensitivity in the contralateral hindpaw. This study demonstrates that prior exposure to 2.5% formalin in the contralateral hindpaw reveals an inhibitory effect of adenosine on peripheral nociception in the presence of glutamate; this conditioning involves microglia and other mechanisms involved in central sensitization.

Adenosine↗
PubMed2004

Assessment of pasteurisation of milk and cream produced by on-farm dairies using a fluorimetric method for alkaline phosphatase activity.

The alkaline phosphatase test is used as an indicator of adequate pasteurisation of milk and cream. A proprietary fluorimetric technique (Fluorophos) is a sensitive and quantitative method for the determination of alkaline phosphatase (ALP) activity in milk products. Currently, adequate pasteurisation of milk products is regarded as confirmed in samples that contain a residual bovine ALP activity of < or =500 mU/litre. This is equivalent to the statutory acceptable level of 4ug phenol/ml required by the EC analytical method. The purpose of the present study was to assess the effectiveness of pasteurisation of milk and cream produced by on-farm dairies. In a longitudinal study over a four-year period, 4,999 samples of milk and cream were collected from 130 on-farm dairies and from two large commercial dairies in NW England for comparison. Bovine ALP activity of >500 mU/litre was deemed as a failure and was found in 3.5% of whole milk, 2.4% semiskimmed milk, 5.0% of skimmed milk, and 39% of cream samples from on-farm dairies. Bovine ALP activity of >100 and <500 mU/litre was found in 18.4% of whole milk, 9.3% of semi-skimmed milk, 13.2% skimmed milk and 44.5% of cream samples from on-farm dairies. Results with skimmed milk samples showed significantly lower bovine ALP activity than whole milk. All 409 milk and cream samples from two large commercial dairies passed the fluorimetric test at less than 500 mU/litre of bovine ALP, and 99% of these milk and cream samples had bovine ALP activity of less than 100 mU/litre. The presence of residual bovine phosphatase indicates a failure and may be due to either inadequate pasteurisation or post pasteurisation contamination with raw milk. Residual bovine phosphatase was demonstrated in 108/114 (94.7%) of milk samples with a bovine ALP activity greater than 500 mU/litre, i.e. true failures. Of more concern is that residual bovine phosphatase was found in 395/401 (98.5%) of samples that gave bovine ALP activity greater than 100 mU/litre but equal to or less than 500 mU/litre. Residual bovine phosphatase was demonstrated in 37/108 (30.2%) of cream samples with bovine ALP activity greater than 500 mU/litre. Presence of reactivated bovine phosphatase is not an indication of a failure but can mask the presence of residual bovine phosphatase. Reactivated bovine phosphatase was found in 74/106 (69.8%) of cream samples. Our results confirm that the more sensitive fluorimetric method is suitable for testing pasteurised whole milk and semiskimmed milk, but for statutory purposes the acceptable level of residual bovine phosphatase should be <100 mU/litre. Our findings have highlighted a potential problem when testing skimmed milk and cream samples from on-farm dairies. To ensure public safety we need more stringent standards for the ALP test and new methods that will accurately confirm that pasteurisation of these products has been achieved.

Alkaline Phosphatase↗
PubMed2003

Differential activation on fMRI of monozygotic twins discordant for AD.

This is the first report of fMRI in monozygotic twins discordant for AD. FMRI brain activation patterns were examined during visuospatial and verbal working memory tasks. The affected twin had greater parietal involvement bilaterally during both working memory tasks and reduced left dorsolateral prefrontal cortex activity on the visuospatial memory task. Thus, fMRI may identify additional brain regions recruited in patients with AD to perform a given cognitive task.

Aged↗
PubMed2003

Short-term temporal variation in PM2.5 mass and chemical composition during the Atlanta Supersite Experiment, 1999.

Measurements in urban Atlanta of transient aerosol events in which PM2.5 mass concentrations rapidly rise and fall over a period of 3-6 hr are reported. The data are based on new measurement techniques demonstrated at the U.S. Environmental Protection Agency (EPA) Atlanta Supersite Experiment in August 1999. These independent instruments for aerosol chemical speciation of NO3-, SO4(2-), NH4+, and organic and elemental carbon (OC and EC), reconstructed the observed hourly dry PM2.5 mass to within 20% or better. Data from the experiment indicated that transient PM2.5 events were ubiquitous in Atlanta and were typically characterized by a sudden increase of EC (soot) and OC in the early morning or SO4(2-) in the late afternoon. The frequent temporal decoupling of these events provides insights into their origins, suggesting mobile sources in metro Atlanta as the main contributor to early morning PM2.5 and more regionally located point SO2 sources for afternoon PM2.5 events. The transient events may also have health implications. New data suggest that short-term PM2.5 exposures may lead to adverse health effects. Standard integrated filter-based techniques used in PM2.5 compliance monitoring networks and in most past PM2.5 epidemiologic studies collect samples over 24-hr periods and thus are unable to capture these transient events. Moreover, health-effects studies that focus on daily PM2.5 mass alone cannot evaluate the health implications of the unique and variable chemical properties of these episodes.

Aerosols↗
PubMed2001

'Drop in' dentistry.

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Anti-Bacterial Agents↗
PubMed2001

Oscillating on borrowed time: diffusible signals from immortalized suprachiasmatic nucleus cells regulate circadian rhythmicity in cultured fibroblasts.

The capacity to generate circadian rhythms endogenously and to confer this rhythmicity to other cells was compared in immortalized cells derived from the suprachiasmatic nucleus (SCN) and a fibroblast line to differentiate SCN pacemaker properties from the oscillatory behavior of non-clock tissues. Only SCN2.2 cells were capable of endogenously generating circadian rhythms in 2-deoxyglucose uptake and Per gene expression. Similar to SCN function in vivo, SCN2.2 cells imposed rhythms of metabolic activity and Per gene expression on cocultured NIH/3T3 fibroblasts via a diffusible signal. The conferred rhythms in NIH/3T3 cells were phase delayed by 4-12 hr relative to SCN2.2 circadian patterns, thus resembling the phase relationship between SCN and peripheral tissue rhythms in vivo. Sustained metabolic rhythmicity in NIH/3T3 cells was dependent on continued exposure to SCN2.2-specific outputs. In response to a serum shock the NIH/3T3 fibroblasts exhibited recurrent oscillations in clock gene expression, but not in metabolic activity. These molecular rhythms in serum-shocked fibroblasts cycled in a phase relationship similar to that observed in the SCN in vivo; peak Per1 and Per2 mRNA expression preceded the rhythmic maxima in Cry1 and Cry2 mRNA levels by 4 hr. Despite these clock gene oscillations the serum-shocked NIH/3T3 cells failed to drive circadian rhythms of Per1 and Per2 expression in cocultures of untreated fibroblasts, suggesting that expression and circadian regulation of the Per and Cry genes are not sufficient to confer pacemaker function. Therefore, SCN-specific outputs are necessary to drive circadian rhythms of metabolic activity, and these output signals are not a direct product of clock gene oscillations.

3T3 Cells↗
PubMed2001

Atypical patterns of cerebral motor activation in autism: a functional magnetic resonance study.

BACKGROUND: Early neurodevelopmental pathogenesis in autism potentially affects emerging functional maps, but little imaging evidence is available. METHODS: We studied eight male autistic and eight matched normal subjects, using functional magnetic resonance imaging during visually paced finger movement, compared to a control condition (visual stimulation in the absence of motor response). RESULTS: Groupwise analyses showed activation in contralateral perirolandic cortex, basal ganglia, and thalamus, bilateral supplementary motor area, and ipsilateral cerebellum for both groups. However, activations were less pronounced in the autism group. Direct group comparisons demonstrated greater activation in perirolandic and supplementary motor areas in the control group and greater activation (or reduced deactivation) in posterior and prefrontal cortices in the autism group. Intraindividual analyses further showed that strongest activations were consistently located along the contralateral central sulcus in control subjects but occurred in locations differing from individual to individual in the autism group. CONCLUSIONS: Our findings, though based on a rather small sample, suggest abnormal individual variability of functional maps and less distinct regional activation/deactivation patterns in autism. The observations may relate to known motor impairments in autism and are compatible with the general hypothesis of disturbances of functional differentiation in the autistic cerebrum.

Adolescent↗
PubMed2001

Attention function and dysfunction in autism.

Impairments of attention are among the most consistently reported cognitive deficits in autism, and they continue to be a key focus of research. This is in no doubt due to the importance of normal attention function to the development of many so-called "higher level" cognitive operations, and to the likely involvement of attention dysfunction in certain clinical features of autism. Autistic individuals display a wide range of attentional abilities and deficits across the many domains of attention function, including selective, sustained, spatial, and shifting attention operations. This unique pattern of attention function and dysfunction has profound implications for the development and treatment of autistic children. The present review will explore this pattern of attentional strengths and weaknesses and the neural defects that underlie them.

Attention↗
PubMed2001

Face processing occurs outside the fusiform 'face area' in autism: evidence from functional MRI.

Processing the human face is at the focal point of most social interactions, yet this simple perceptual task is difficult for individuals with autism, a population that spends limited amounts of time engaged in face-to-face eye contact or social interactions in general. Thus, the study of face processing in autism is not only important because it may be integral to understanding the social deficits of this disorder, but also, because it provides a unique opportunity to study experiential factors related to the functional specialization of normal face processing. In short, autism may be one of the only disorders where affected individuals spend reduced amounts of time engaged in face processing from birth. Using functional MRI, haemodynamic responses during a face perception task were compared between adults with autism and normal control subjects. Four regions of interest (ROIs), the fusiform gyrus (FG), inferior temporal gyrus, middle temporal gyrus and amygdala were manually traced on non-spatially normalized images and the percentage ROI active was calculated for each subject. Analyses in Talairach space were also performed. Overall results revealed either abnormally weak or no activation in FG in autistic patients, as well as significantly reduced activation in the inferior occipital gyrus, superior temporal sulcus and amygdala. Anatomical abnormalities, in contrast, were present only in the amygdala in autistic patients, whose mean volume was significantly reduced as compared with normals. Reaction time and accuracy measures were not different between groups. Thus, while autistic subjects could perform the face perception task, none of the regions supporting face processing in normals were found to be significantly active in the autistic subjects. Instead, in every autistic patient, faces maximally activated aberrant and individual-specific neural sites (e.g. frontal cortex, primary visual cortex, etc.), which was in contrast to the 100% consistency of maximal activation within the traditional fusiform face area (FFA) for every normal subject. It appears that, as compared with normal individuals, autistic individuals 'see' faces utilizing different neural systems, with each patient doing so via a unique neural circuitry. Such a pattern of individual-specific, scattered activation seen in autistic patients in contrast to the highly consistent FG activation seen in normals, suggests that experiential factors do indeed play a role in the normal development of the FFA.

Adult↗