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Biomedical subjects

G Taylor

Publications and source records attributed to G Taylor.

At least 37 records · Page 2Linked to original sources
PubMed2003

Controlled optimization of mode conversion from electron Bernstein waves to extraordinary mode in magnetized plasma.

In the CDX-U spherical torus, agreement between radiation temperature and Thomson scattering electron temperature profiles indicates approximately 100% conversion of thermally emitted electron Bernstein waves to the X mode. This has been achieved by controlling the electron density scale length (L(n)) in the conversion region with a local limiter outside the last closed flux surface, shortening L(n) to the theoretically required value for optimal conversion. From symmetry of the conversion process, prospects for efficient coupling in heating and current drive scenarios are strongly supported.

Journal Article↗
PubMed2003

A comparison of bone loss in early and late rheumatoid arthritis using quantitative phalangeal ultrasound.

This study compares amplitude-dependent speed of sound (AD-SoS) measured by phalangeal ultrasonography in a group of 60 patients with early rheumatoid arthritis (RA) with those who had had the disease for more than 4 years. The mean duration of the early disease group was 1.4 years, and the mean of the established RA group was 14.6 years. Plasma viscosity (PV), C-reactive protein (CRP) and HAQ scores were obtained. Forty-nine patients with early RA had hand radiographs assessed by the Larsen score method. The DBM Sonic system was assessed on normal volunteers and a coefficient of variation of 0.88% obtained. A significant correlation was found between the left and right hands of the patients groups studied ( r=0.84). The mean Z score of both hands was therefore used in comparing the two clinical groups. Results showed no correlation between CRP, PV and Z scores of AD-SoS. The HAQ scores showed a weak negative correlation, and there was no correlation between the Larsen score and Z score, or the number of swollen joints and Z score. However, the early and established groups with RA were significantly different (#E5/E5#=0.004). Within the early RA group the Z score for AD-SoS was lower in those with disease duration of less than 2 years (-1.71) than in those with disease duration of 2-4 years (-1.01). This suggests that bone loss in the fingers is greater in the first 2 years of disease than in the following 2 years, which might reflect an effect of treatment.

Absorptiometry, Photon↗
PubMed2003

Carpal tunnel syndrome - is high-frequency ultrasound a useful diagnostic tool?

This study assessed the clinical use of three ultrasound measurements; median nerve cross-sectional area, median nerve flattening ratio and palmar displacement of the flexor retinaculum, for the diagnosis of carpal tunnel syndrome. The measurements were made in 20 carpal tunnel sufferers and 20 controls. The sensitivity, specificity and predictive values of each were calculated in various clinical settings. Values for each of the three variables were significantly different in the patient and control populations. The differences we recorded were smaller than those found in previous studies. The tests had a sensitivity of 72% and a specificity of 90%. Alterations in the morphology of the carpal tunnel in patients with carpal tunnel syndrome can be measured in the district general hospital setting. The measurements described maybe a useful non-invasive confirmatory test in patients in whom there is a strong clinical suspicion of carpal tunnel syndrome. However, they would be of no benefit in epidemiological surveys of populations with a low incidence of carpal tunnel syndrome.

Adult↗
PubMed2002

LightCycler qPCR optimisation for low copy number target DNA.

The LightCycler is a rapid air-heated thermal cycler which incorporates a fluorimeter for the detection and quantification of Polymerase Chain Reaction (PCR) amplified products. It provides real-time cycle-by-cycle analysis of product generation. Amplification occurs in glass capillary tubes. The products are detected using a fluorescent double stranded DNA binding dye or fluorescent probes. However, conditions that work well in conventional PCR reactions do not readily translate to the LightCycler. Whilst using this new technology to study an infectious pathogen in human tissue samples, several parameters were identified which can have an adverse effect on the reliable and reproducible quantification of low copy number target DNA. They included abstraction of PCR reagents on glass, primer-dimer formation, non-specific product generation, and a failure to amplify low copy number target when it is present in a high background of human chromosomal DNA. For each problem identified, several solutions are described. Novel approaches are also described to ensure that amplification of target DNA and of the quantification standards occurs with the same efficiency. With appropriate changes to the protocols currently in use, LightCycler quantitative Polymerase Chain Reaction (LC-qPCR) can be used to achieve a level of accuracy that exceeds that of an enzyme immunoassay. The LC-qPCR optimisation strategies described are of particular relevance when applying this technology to the study of pathogens in tissue samples. The technique offers the enormous potential for reliable and reproducible quantitative PCR of low copy number target DNA.

DNA Primers↗
PubMed2002

Florid infectious mononucleosis: clinicopathological correlation in acute tonsillectomy.

In patients with infectious mononucleosis (IM), acute tonsillectomy is advocated only in the minority who develop severe airway compromise. In such florid cases, the pathological diagnosis of IM, well known to morphologically simulate that of lymphoma, is particularly challenging. The present case describes a 15-year old male with a clinical course consistent with IM in whom acute tonsillectomy was performed due to progressive airway obstruction. The striking histological findings emphasize the need for close clinicopathological correlation. Recently available ancillary studies are described which both surgeon and pathologist should be familiar with in the differentiation of IM from other lymphoproliferative conditions.

Adolescent↗
PubMed2002

Role of bovine chemokines produced by dendritic cells in respiratory syncytial virus-induced T cell proliferation.

Respiratory syncytial virus (RSV) has been reported to induce the production of chemokines in the airway epithelia. Dendritic cells (DC) are the most potent antigen-presenting cells. They are located throughout the body and release chemokines in response to inflammation and infection. We have investigated the chemokine profile of bovine DC in response to exposure to bovine RSV (BRSV). Transcripts for several chemokines were detected by RT-PCR, subsequently cloned and expressed, and the products analysed by western blotting. To test the effect of the recombinant chemokines on RSV-induced T cell proliferation, DC were pulsed with BRSV, irradiated, and added to purified bovine CD4(+) T cells from RSV-immune cattle in combination with various concentrations of recombinant chemokines, and the proliferative response of the T cells assessed. Eotaxin was the only chemokine, of those investigated, that specifically enhanced the T cell response to BRSV-pulsed DC. Addition of MIP-1alpha to control wells or to wells containing BRSV-pulsed DC had similar effects, suggesting non-specific stimulation of T cells. RANTES and MIP-3alpha did not seem to influence the proliferative response of T cells co-cultured with BRSV-pulsed DC. Thus, although BRSV induced the production of several chemokines by DC, only eotaxin promoted a BRSV specific CD4(+) T cell proliferative response.

Animals↗
PubMed2002

Manipulation under anaesthesia for frozen shoulder.

Following manipulation of frozen shoulders under general anaesthesia, we reviewed 74 shoulders at an average of 3 weeks and again at an average of 33 months following the manipulation. We used an adjusted Constant score by excluding the abduction strength measurement. The maximum score was therefore 75 points. The average pre-manipulation score was 24.7 points. At 3 weeks after manipulation this score improved to 54.9 points. At the last follow-up (average 33 months) the score was 72.4 points. We have shown that manipulation under general anaesthesia speeds up recovery of frozen shoulders, and the range of movement improves rapidly.

Adult↗
PubMed2002

Characteristics of the first H-mode discharges in the national spherical torus experiment.

We report observations of the first low-to-high ( L-H) confinement mode transitions in the National Spherical Torus Experiment. The H-mode energy confinement time increased over reference discharges transiently by 100-200%, as high as approximately 100 ms. This confinement time is approximately 2 times higher than predicted by a multimachine scaling. Thus the confinement time of spherical tori has been extended to a record high value, leading to an eventual revision of confinement scalings. Finally, the power threshold for H-mode access is >10x higher than predicted by an international scaling from conventional aspect-ratio tokamaks, which could lead to new understanding of H-mode transition dynamics.

Journal Article↗
PubMed2002

The natural history of developmental dysplasia of the hip after early supervised treatment in the Pavlik harness. A prospective, longitudinal follow-up.

Between June 1988 and December 1997, we treated 332 babies with 546 dysplastic hips in a Pavlik harness for primary developmental dysplasia of the hip as detected by the selective screening programme in Southampton. Each was managed by a strict protocol including ultrasonic monitoring of treatment in the harness. The group was prospectively studied during a mean period of 6.5 +/- 2.7 years with follow-up of 89.9%. The acetabular index (AI) and centre-edge angle of Wiberg (CEA) were measured on annual radiographs to determine the development of the hip after treatment and were compared with published normal values. The harness failed to reduce 18 hips in 16 patients (15.2% of dislocations, 3.3% of DDH). These required surgical treatment. The development of those hips which were successfully treated in the harness showed no significant difference from the normal values of the AI for the left hips of girls after 18 months of age. Of those dysplastic hips which were successfully reduced in the harness, 2.4% showed persistent significant late dysplasia (CEA <20 degrees) and 0.2% persistent severe late dysplasia (CEA <15 degrees). All could be identified by an abnormal CEA (<20 degrees) at five years of age, and many from the progression of the AI by 18 months. Dysplasia was considered to be sufficient to require innominate osteotomy in five (0.9%). Avascular necrosis was noted in 1% of hips treated in the harness. We conclude that, using our protocol, successful initial treatment of DDH with the Pavlik harness appears to restore the natural development of the hip to normal. We suggest that regular radiological surveillance up to five years of age is a safe and effective practice.

Acetabulum↗
PubMed2002

Downstream flow event sampling of acid mine drainage from the historic Mt Morgan Mine.

Numerous scientific reports concur that the Dee River is heavily impacted by acid mine drainage from the historic gold and copper mine at Mt Morgan, Central Queensland. The water quality along the Dee River, for 18 km downstream of the mine she to is junction with Fletcher Creek, is characterised by low pH, typically 2.8 to 4.2. With respect to metal concentrations, the Dee River has been described as one of Australia's most polluted rivers. Measurements of pH along the Dee River clearly demonstrated the movement of a slug of acidic water down the river during each of the four flow events between November 2000 and February 2001. Laboratory analysis of water samples collected during November indicated Al, Cu and Zn concentrations orders of magnitude above ANZECC guidelines. Fish kills occurred with each flow event and killed an estimated total of 26,000 fish.

Animals↗
PubMed2001

Does Council Tax Valuation Band (CTVB) correlate with Under-Privileged Area 8 (UPA8) score and could it be a better 'Jarman Index'?

BACKGROUND: Widespread scepticism persists on the use of the Under-Privileged Area (UPA8) score of Jarman in distributing supplementary resources to so-attributed 'deprived' UK general practices. The search for better 'needs' markers continues. Having already shown that Council Tax Valuation Band (CTVB) is a predictor of UK GP workload, we compare, here, CTVB of residence of a random sample of patients with their respective 'Jarman' scores. METHODS: Correlation coefficient is calculated between (i) the CTVB of residence of a randomised sample of patients from an English general practice and (ii) the UPA8 scores of the relevant enumeration districts in which they live. RESULTS: There is a highly significant correlation between the two measures despite modest study size of 478 patients (85% response). CONCLUSIONS: The proposal that CTVB is a marker of deprivation and of clinical demand should be examined in more detail: it correlates with 'Jarman', which is already used in NHS resource allocation. But unlike 'Jarman', CTVB is simple, objective, and free of the problems of Census data. CTVB, being household-based, can be aggregated at will.

Catchment Area, Health↗
PubMed2001

A recessive form of the Ehlers-Danlos syndrome caused by tenascin-X deficiency.

BACKGROUND: The Ehlers-Danlos syndrome is a heritable connective-tissue disorder caused by defects in fibrillar-collagen metabolism. Mutations in the type V collagen genes account for up to 50 percent of cases of classic Ehlers-Danlos syndrome, but many other cases are unexplained. We investigated whether the deficiency of the tenascins, extracellular-matrix proteins that are highly expressed in connective tissues, was associated with the Ehlers-Danlos syndrome. METHODS: We screened serum samples from 151 patients with the classic, hypermobility, or vascular types of the Ehlers-Danlos syndrome; 75 patients with psoriasis; 93 patients with rheumatoid arthritis; and 21 healthy persons for the presence of tenascin-X and tenascin-C by enzyme-linked immunosorbent assay. We examined the expression of tenascins and type V collagen in skin by immunohistochemical methods and sequenced the tenascin-X gene. RESULTS: Tenascin-X was present in serum from all normal subjects, all patients with psoriasis, all patients with rheumatoid arthritis, and 146 of 151 patients with the Ehlers-Danlos syndrome. Tenascin-X was absent from the serum of the 5 remaining patients with Ehlers-Danlos syndrome, who were unrelated. Tenascin-X deficiency was confirmed in these patients by analysis of skin fibroblasts and by immunostaining of skin. The expression of tenascin-C and type V collagen was normal in these patients. All five of these patients had hypermobile joints, hyperelastic skin, and easy bruising, without atrophic scarring. Tenascin-X mutations were identified in all tenascin-X-deficient patients; one patient had a homozygous tenascin-X gene deletion, one was heterozygous for the deletion, and three others had homozygous truncating point mutations, confirming a causative role for tenascin-X and a recessive pattern of inheritance. CONCLUSIONS: Tenascin-X deficiency causes a clinically distinct, recessive form of the Ehlers-Danlos syndrome. This finding indicates that factors other than the collagens or collagen-processing enzymes can cause the syndrome and suggests a central role for tenascin-X in maintaining the integrity of collagenous matrix.

Arthritis, Rheumatoid↗
PubMed2001

Processing of a multiple membrane spanning Epstein-Barr virus protein for CD8(+) T cell recognition reveals a proteasome-dependent, transporter associated with antigen processing-independent pathway.

Epstein-Barr virus (EBV) latent membrane protein (LMP)2 is a multiple membrane spanning molecule which lacks ectodomains projecting into the lumen of the endoplasmic reticulum (ER). Human CD8(+) cytotoxic T lymphocytes (CTL)s recognize a number of epitopes within LMP2. Assays with epitope-specific CTLs in two different cell backgrounds lacking the transporter associated with antigen processing (TAP) consistently show that some, but not all, LMP2 epitopes are presented in a TAP-independent manner. However, unlike published examples of TAP-independent processing from endogenously expressed antigens, presentation of TAP-independent LMP2 epitopes was abrogated by inhibition of proteasomal activity. We found a clear correlation between hydrophobicity of the LMP2 epitope sequence and TAP independence, and experiments with vaccinia minigene constructs expressing cytosolic epitope peptides confirmed that these more hydrophobic peptides were selectively able to access the HLA class I pathway in TAP-negative cells. Furthermore, the TAP-independent phenotype of particular epitope sequences did not require membrane location of the source antigen since (i) TAP-independent LMP2 epitopes inserted into an EBV nuclear antigen and (ii) hydrophobic epitope sequences native to EBV nuclear antigens were both presented in TAP-negative cells. We infer that there is a proteasome-dependent, TAP-independent pathway of antigen presentation which hydrophobic epitopes can selectively access.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Community care.

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Community Dentistry↗
PubMed2001

Identification of CD4+ T cell epitopes on the fusion (F) and attachment (G) proteins of bovine respiratory syncytial virus (BRSV).

To gain insight into the antigenic structure of the F and G proteins of BRSV, we have mapped CD4+ T cell epitopes on these proteins using synthetic peptides and lymphocytes from vaccinated, naturally infected or experimentally infected calves, in proliferation assays. Bovine CD4+ T cells recognised epitopes that were distributed predominantly within the F1 subunit of the F protein, some of which were adjacent to previously identified B cell epitopes. Bovine CD4+ T cell epitopes within the G protein were mainly located within the cytoplasmic tail. Several immunodominant bovine T cell epitopes within the F protein, that were recognised by calves with different haplotypes, are also recognised by human T cells. Thus, cattle and humans appear to recognise similar T cell epitopes on the F protein. Studies using antibodies to bovine MHC class II and BoLA DR-transfected CHO cells as antigen-presenting cells indicated that immunodominant regions of the F and G proteins contained both DR- and DQ-restricted epitopes. The finding that there was little recognition of the extracellular domain of the G protein by T cells has important implications for vaccine design based on the soluble form of this protein.

Animals↗
PubMed2001

Increased leaf area expansion of hybrid poplar in elevated CO2. From controlled environments to open-top chambers and to FACE.

We examined the response of hybrid poplar to elevated CO2 in contrasting growth environments: controlled environment chamber (CE). open-top chamber (OTC) and poplar free air CO2 enrichment (POPFACE) in order to compare short versus long-term effects and to determine whether generalisations in response are possible for this fast growing tree. Leaf growth, which for poplar is an important determinant of stemwood productivity was followed in all environments, as were the determinants of leaf growth-cell expansion and cell production. Elevated CO2 (550-700 micromol mol(-1), depending on environment) resulted in an increase in final leaf size for Populus trichocarpa x Populus deltoides (Populus x interamericana) and P. deltoides x Populus nigra (Populus x euramericana), irrespective of whether plants were exposed during a short-term CE glasshouse study (90 days), a long-term OTC experiment (3 years) or during the first year of a POPFACE experiment. An exception was observed in the closed canopy POPFACE experiment, where final leaf size remained unaltered by CO2. Increased leaf extension rate was observed in elevated CO2 in all experiments, at some point during leaf development, as determined by leaf length. Again the exception were the POPFACE experiment, where effects were not statistically significant. Leaf production and specific leaf area (SLA) were increased and decreased, respectively, on five out of six occasions, although both were only statistically significant on two occasions and interestingly for SLA never in the FACE experiment. Although both cell expansion and cell production were sensitive to CO2 concentration, effects appeared highly dependent on growth environment and genotype. However, increased leaf cell expansion in elevated CO2 was often associated with changes in the biophysical properties of the cell wall, usually increased cell wall plasticity. This research has shown that enhanced leaf area development was a consistent response to elevated CO2 but that the magnitude of this response is likely to decline, in long-term exposure to elevated CO2. Effects on SLA and leaf production suggest that CE and OTC experiments may not always provide good predictors of the 'qualitative' effects of elevated CO2 in long-term ecosystem experiments.

Air Pollutants↗