Biomedical subjects
Publications and source records attributed to R Harper.
This case study highlights the importance of providing holistic and multidisciplinary care when managing patients with complex bilateral traumatic hand wounds. Such collaboration can achieve optimum results.
AIM: To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS. METHODS: Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patient's GP was informed in all cases. RESULTS: The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately 17 pounds sterling per patient. CONCLUSION: Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.
The hyf locus (hyfABCDEFGHIJ-hyfR-focB) of Escherichia coli encodes a putative 10-subunit hydrogenase complex (hydrogenase-4 [Hyf]); a potential sigma(54)-dependent transcriptional activator, HyfR (related to FhlA); and a putative formate transporter, FocB (related to FocA). In order to gain insight into the physiological role of the Hyf system, we investigated hyf expression by using a hyfA-lacZ transcriptional fusion. This work revealed that hyf is induced under fermentative conditions by formate at a low pH and in an FhlA-dependent fashion. Expression was sigma(54) dependent and was inhibited by HycA, the negative transcriptional regulator of the formate regulon. Thus, hyf expression resembles that of the hyc operon. Primer extension analysis identified a transcriptional start site 30 bp upstream of the hyfA structural gene, with appropriately located -24 and -12 boxes indicative of a sigma(54)-dependent promoter. No reverse transcriptase PCR product could be detected for hyfJ-hyfR, suggesting that hyfR-focB may be independently transcribed from the rest of the hyf operon. Expression of hyf was strongly induced ( approximately 1,000-fold) in the presence of a multicopy plasmid expressing hyfR from a heterologous promoter. This induction was dependent on low pH, anaerobiosis, and postexponential growth and was weakly enhanced by formate. The hyfR-expressing plasmid increased fdhF-lacZ transcription just twofold but did not influence the expression of hycB-lacZ. Interestingly, inactivation of the chromosomal hyfR gene had no effect on hyfA-lacZ expression. Purified HyfR was found to specifically interact with the hyf promoter/operator region. Inactivation of the hyf operon had no discernible effect on growth under the range of conditions tested. No Hyf-derived hydrogenase or formate dehydrogenase activity could be detected, and no Ni-containing protein corresponding to HyfG was observed.
BACKGROUND: Many studies have estimated observer variability for optic disc assessment among experts, but there are few data on agreement between optometrists and ophthalmologists. The aim of this study is to report inter- and intraobserver agreement among optometrists and ophthalmologists in optic disc assessment and discuss the implications for glaucoma co-management. METHODS: Twelve observers (six optometrists and six ophthalmologists) graded 48 stereo-pairs of optic disc photographs from 48 patients on two separate occasions. Observers graded the vertical C/D ratio, the narrowest rim width and the presence/absence of disc haemorrhage. Agreement was assessed by calculating the standard deviation (SD) of differences and the kappa statistic, within and between observers. Systematic differences in grading between and within individuals were described by calculating mean differences. RESULTS: Intra-observer agreement is "substantial" and significantly better than inter-observer agreement for all disc features (P<0.0001). Intra-observer agreement is comparable for optometrists and ophthalmologists with regard to C/D ratio estimates. Although some optometrists show close agreement with ophthalmologists, overall agreement between optometrists and ophthalmologists is significantly worse than agreement among ophthalmologists alone for vertical C/D ratio (P=0.002) and disc haemorrhage (P=0.02). There are fewer inter-observer mean differences that differ significantly from zero among ophthalmologists (7%) than among optometrists (67%; chi2=11.63, P<0.001) or between optometrists and ophthalmologists (69%; chi2=16.7, P<0.001). There is evidence of systematic under-reading of C/D ratios by less experienced optometrists. CONCLUSION: Although individual optometrists can show good agreement with ophthalmologists on disc grading, the variation in individual performance indicates that training and accreditation in disc assessment is an essential prerequisite for participation by optometrists in glaucoma co-management.
A number of studies have measured the outcomes of low vision care but these have usually been longitudinal case series, thus constituting very low quality of evidence for effectiveness. To date, there have been no randomised controlled trials (RCTs) which have evaluated the effectiveness and cost effectiveness of different models of care in low vision. The size of the low vision population and the paucity of systematic evaluation have created a pressing need for evidence about cost-effectiveness in order to inform service developments for low vision rehabilitation. This paper describes the study design and methodology of a three-arm RCT currently under way in Manchester. The baseline population recruited is also described. A traditional hospital-based optometric service is being compared with an integrated service (comprising the addition of community-based rehabilitation officer input) and with more generic community input (which is non-integrated and is not vision specific). A wide range of outcome measures are being assessed at recruitment and 12 months post-intervention, including low vision specific and generic quality of life measures, patterns of low vision aid use, and task performance. The rationale for the trial is discussed and the main study outcomes are described.
Increasing evidence indicates that intracellular redox status modulates the activity of various transcriptional factors, including nuclear factor (NF)-kappa B and activator protein-1. Our laboratory has been interested in characterizing the role thioredoxin (TRX) plays in regulating cellular redox status in airway epithelium. TRX is a small, ubiquitous protein with two redox-active half-cysteine residues, -Cys-Gly-Pro-Cys, in its active center. Using primary passage-1 human tracheobronchial epithelial cell cultures and an immortalized human bronchial epithelial cell line, HBE1, we observed that tumor necrosis factor (TNF)-alpha enhanced NF-kappa B transcriptional activity. This observation was based on gel mobility shift assays and interleukin (IL)-8 promoter-reporter gene transfection studies. TNF-alpha activation coincided with translocation of NF-kappa B p65 from the cytoplasm to the nucleus. Pretreatment with N-acetyl-cysteine (NAC) (1 to 10 mM) or glutathione (1 to 10 mM) inhibited TNF-alpha-induced activation of NF-kappa B transcriptional activity and IL-8 promoter-mediated reporter gene expression. In contrast, elevated TRX protein levels in cells enhanced TNF-alpha-dependent NF-kappa B transcriptional activity and IL-8 promoter activity. This observation was independent of the manner in which TRX was elevated in cells (e.g., by cotransfection with a FLAG-TRX expression clone, or by direct exposure to commercially available human TRX protein). Localization of TRX protein by anti-TRX antibody indicated an accumulation of TRX protein in the nucleus after TNF-alpha treatment. The nuclear localization phenomenon was different from the major cytosolic accumulation of glutathione and NAC. This is the first known report demonstrating movement of TRX into the nucleus of airway epithelial cells after an inflammatory stress. These results suggest a compartment effect of thiol chemicals in the regulation of redox-dependent transcriptional activity.
BACKGROUND: Previous studies have shown that the cup:disc (C/D) ratio has limited sensitivity and specificity. Improved sensitivity and specificity has been found with combinations of disc parameters using stereophotography or disc imaging, but the extent to which these studies reflect what can be achieved by direct assessment is unclear. The purpose of this paper is to report the sensitivities and specificities of a range of disc parameters, both in isolation and in combination, as graded during clinical examination with direct ophthalmoscopy. METHODS: Sixty-seven patients with newly diagnosed primary open angle glaucoma and 145 non-glaucomatous subjects were examined by direct ophthalmoscopy. The following features of the optic disc were graded: vertical and horizontal C/D ratios (uncorrected for disc size), narrowest rim width, presence/absence of disc haemorrhage, focal pallor of the neuroretinal rim, parapapillary atrophy, steepness of the cup-edge and presence/absence of baring of the lamina cribrosa. Subjects were validated as glaucomatous/non-glaucomatous on the basis of visual fields, independently of the results of optic disc gradings. Multiple logistic regression modelling was used to evaluate the effectiveness of combinations of disc parameters. RESULTS: Sensitivities and specificities are limited for all features when considered in isolation. The 'cupping' parameters have the highest sensitivities and specificities but no single cut-off criterion for these parameters has both high sensitivity and specificity. Multiple logistic regression modelling indicated that two disc parameters in combination, narrowest rim width and parapapillary atrophy, were independently associated with glaucoma and achieved best prediction. Combining information from these parameters achieved a sensitivity of 81% (95% CI = 69-89%) and a specificity of 90% (95% CI = 84-95%), a level of discrimination that is not significantly better than narrowest rim width alone in terms of area under the receiver operator characteristic (ROC) curve. CONCLUSION: Disc assessment during clinical examination with direct ophthalmoscopy can achieve comparable sensitivities and specificities with those previously reported for stereophotographic assessment or visual fields screening. However, since the diagnostic accuracy of disc assessment in isolation is inadequate for screening, a combined test strategy is necessary.
AIMS: To evaluate visual function and vision specific health status in patients undergoing penetrating keratoplasty for keratoconus. METHODS: A prospective longitudinal study measuring logMAR visual acuity, contrast sensitivity, disability glare, binocular visual field, stereoacuity, and subjective visual function (VF-14) was conducted on 18 patients with keratoconus undergoing penetrating keratoplasty (PK), including six patients who had already had PK in the fellow eye. Data were collected preoperatively and at 3, 9, and 18 months after surgery. RESULTS: Within 3 months of surgery there was significant improvement in aided visual acuity, contrast sensitivity, and stereoacuity (p<0.05); disability glare (p<0.05) no longer had a significant detrimental effect on these variables. VF-14 score improved significantly throughout the postoperative period (p<0.05). There was significant correlation of the VF-14 score with aided visual acuity, binocular visual field, and stereoacuity. Postoperative astigmatism (<4D v >4D) did not affect the VF-14 score significantly. CONCLUSIONS: There is substantial and rapid improvement in visual function and vision specific health status in keratoconic patients as a result of uncomplicated penetrating keratoplasty.
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BACKGROUND: The safety and predictability of refractive surgery for all degrees of myopia is now becoming established. It is therefore appropriate to evaluate whether there is a patient driven demand for such treatments and, if so, to establish guidelines for its provision within the National Health Service (NHS). METHODS: A comparative study was designed to assess the effect of degree of myopia on quality of life ("high" (n = 30) -10.00D, worse eye; "moderate" (n = 40) -4.00 to -9.75D, worse eye; "low" (n = 42) <-4. 00D, worse eye) compared with a group of patients with keratoconus (n = 30) treated by optical correction. Data collection included binocular logMAR visual acuity, Pelli-Robson low contrast letter sensitivity, questionnaires to assess subjective visual function (VF-14) and effect on quality of life (VQOL), and semi-structured interviews. RESULTS: There were no significant differences in any of the measures between patients with a high degree of myopia and those with keratoconus, or between those with a low and those with a moderate degree of myopia. However, those with a high degree of myopia had highly significantly poorer logMAR, VF-14, and VQOL scores than those with low and moderate myopia (p<0.001). Interview data supported these findings with patients with a high degree of myopia and those with keratoconus reporting that psychological, cosmetic, practical, and financial factors affected their quality of life. CONCLUSION: Compared with low and moderate myopia, patients with a high degree of myopia experience impaired quality of life similar to that of patients with keratoconus. Criteria should therefore be identified to enable those in sufficient need to obtain refractive surgical treatment under the NHS.
A 3- to 8-fold stimulation of interleukin (IL)-8 gene expression by all-trans-retinoic acid (ATRA) was demonstrated in primary cultures of human and monkey tracheobronchial epithelial cells and BEAS-2B serum-sensitive cell line. The effect of ATRA on IL-8 gene expression is dose- and time-dependent. Using cycloheximide, it was observed that new protein synthesis was required for the stimulation. ATRA had no effect on IL-8 messenger RNA stability. A difference in nuclear run-on activity suggests that a transcriptional mechanism is involved in ATRA-enhanced IL-8 gene expression. Promoter-reporter gene transfection studies demonstrated ATRA enhanced IL-8 promoter activity, especially when cells were cotransfected with retinoic acid nuclear receptor-alpha expression vector. Deletion and site-directed mutagenesis analysis revealed the involvement of nuclear factor (NF)-kappaB binding site of the IL-8 gene in ATRA-enhanced promoter activity. Electrophoretic mobility shift assay (EMSA) demonstrated that ATRA enhanced DNA-NF-kappaB complex formation, especially with the p65 subunit. Western blot analysis demonstrated that ATRA did not enhance the protein amount of both the p50 and the p65 subunits in the nuclei. Because ATRA also enhances thioredoxin (TRX) gene expression, the effect of TRX on IL-8 gene expression was examined. IL-8 promoter activity was enhanced in transfected cells by the addition of TRX protein. Treatment of nuclear extracts with TRX also enhanced DNA- NF-kappaB complex formation as observed by EMSA, particularly the p65 subunit. Taking these data together, a novel mechanism is proposed in which ATRA activates promoter activity of IL-8 gene through TRX-dependent NF-kappaB activation.
Demonstrating that optometrists can make valid and reliable assessments of optic disc features is an important prerequisite for establishing schemes for shared care/co-management. Previous studies have estimated observer variability among experts in the assessment of optic disc cupping, but there has been a paucity of information on observer variability amongst optometrists. This paper describes a study to investigate intra- and inter-observer variability for a range of disc features, as graded by both ophthalmologists and optometrists. Five observers (three optometrists and two ophthalmologists) graded 48 stereo-pairs of optic disc photographs from 48 patients on two separate occasions. Each observer graded the following features: vertical and horizontal C/D ratios, narrowest rim width, the presence/absence of a disc haemorrhage, focal pallor of the neuroretinal rim, peri-papillary atrophy, the steepness of the cup-edge and the presence/absence of the cribriform sign. The average intra- and inter-observer standard deviation (SD) of differences are, respectively, 0.11 and 0.19 for the vertical C/D ratios and 0.10 and 0.18 for the horizontal C/D ratios. For the vertical C/D ratio the average weighted kappa (kappa w) is 0.79 within observers and 0.46 between observers. Percentage agreements for the presence/absence of a disc haemorrhage range from 96 to 100% (average kappa = 0.92) within observers and from 90 to 98% (average kappa = 0.77) between observers. For other disc features, average kappa w values range from 0.67 to 0.71 within observers and from 0.23 to 0.46 between observers. Intra- and inter-observer comparisons (within and between different professionals) across all disc features are comparable for the optometrists and ophthalmologists, thus demonstrating that optometrists can make valid assessments of disc features. The implications for shared care are discussed.
Small, multigene families organized in a tandem array can facilitate the rapid evolution of the gene cluster by a process of meiotic unequal crossing-over. To study this process in a multicellular organism, we created a synthetic RBCSB gene cluster in Arabidopsis thaliana and used this to measure directly the frequency of meiotic, intergenic unequal crossing-over between sister chromatids. The synthetic RBCSB gene cluster was composed of a silent DeltaRBCS1B::LUC chimeric gene fusion, lacking all 5' transcription and translation signals, followed by RBCS2B and RBC3B genomic DNA. Expression of luciferase activity (luc(+)) required a homologous recombination event between the DeltaRBCS1B::LUC and the RBCS3B genes, yielding a novel recombinant RBCS3B/ 1B::LUC chimeric gene whose expression was driven by RBCS3B 5' transcription and translation signals. Using sensitive, single-photon-imaging equipment, three luc(+) seedlings were identified in more than 1 million F2 seedlings derived from self-fertilized F1 plants hemizygous for the synthetic RBCSB gene cluster. The F2 luc(+) seedlings were isolated, and molecular and genetic analysis indicated that the luc(+) trait was caused by the formation of a recombinant chimeric RBCS3B/1B::LUC gene. A predicted duplication of the RBCS2B gene also was present. The recombination resolution break points mapped adjacent to a region of intron I at which a disjunction in sequence similarity between RBCS1B and RBCS3B occurs; this provided evidence supporting models of gene cluster evolution by exon-shuffling processes. In contrast to most measures of meiotic unequal crossing-over that require the deletion of a gene in a gene cluster, these results directly measured the frequency of meiotic unequal crossing-over (approximately 3 x 10(-6)), leading to the expansion of the gene cluster and the formation of a novel recombinant gene.
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BACKGROUND: Previous work with schizophrenic children disclosed deficits on two continuous performance tests (CPTs) and ERP indices of reduced attentional resource allocation. METHODS: The two CPTs were administered to adult schizophrenics and matched control subjects. The simple CPT required only that the subject respond whenever the target digit was displayed. The complex version required a response whenever any digit was displayed on two successive trials. Event-related potentials (ERPs) were recorded during task performance. RESULTS: Schizophrenics had fewer hits on both CPT versions, showed a greater drop in performance from the simple to the complex CPT, and took longer to respond than controls. The processing negativity (Np) showed a greater amplitude increase from nontarget to target in normals than in schizophrenics, and the overlapping P2 component was more negative in normals. P3 latency was longer in schizophrenics, but P3 amplitude did not differ. CONCLUSIONS: Group performance and processing negativity effects replicated those from an earlier study of schizophrenic and normal children administered the same versions of the CPT, suggesting similar abnormalities in the allocation and modulation of information processing resources.
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BACKGROUND: Brain metabolite levels are measured by proton magnetic resonance spectroscopy (1H MRS) and include N-acetylaspartate (NAA), creatine (Cr), choline (Cho), and lactate and the ratios NAA to Cho and Cr (NAA-ChoCr), NAA-Cr, NAA-Cho, and Cho-Cr. Brain metabolite levels may correlate with the degree of neonatal asphyxia. OBJECTIVE: To determine which brain metabolite ratios have the strongest correlation with the Apgar scores in infants with possible asphyxia; whether the correlation is stronger with basal ganglia (BG) or anterior border-zone metabolites; and whether a combined approach using routine MR imaging (MRI), diffusion-weighted MRI, and MRS can be used to evaluate the severity of neonatal asphyxia. METHODS: Twenty infants with 1-minute Apgar scores of 6 or less were studied at 2 to 28 days of age. The MRS variables were compared with routine and diffusion-weighted brain MRI. Clinical variables and MRS findings were subjected to factor analysis and stepwise multiple regressions to determine interrelationships. RESULTS: The BG region NAA-Cho and NAA-ChoCr ratios correlated with the 1-minute (P<.001) and 5-minute (P = .01 for NAA-Cho; P = .006 for NAA-ChoCr). There was no correlation between metabolite levels and the 10-minute Apgar scores. The stongest predictions exist between the 1-minute Apgar scores and the NAA-Cho and NAA-ChoCr ratios. In the anterior border zone, the only correlation was between the 1-minute Apgar score and the NAA-Cho ratio, but there was a strong age effect in these data. Lactate was found in the BG of 3 infants, all of whom had 5-minute Apgar scores of 6 or less. Three patients had focal lesions on MRI; 2 of these had elevated lactate levels in the abnormal region; and the third, who had an intrauterine stroke, had no lactate in the region. CONCLUSIONS: Correlations between NAA-Cho and NAA-ChoCr ratios and the 1- and 5-minute Apgar scores are stronger in the BG region than in the frontal border zone. The presence or absence of lactate may indicate the severity of the brain insult, and the combination of MRS, MRI, and diffusion-weighted MRI may assist in localizing and predicting a long-term brain injury.
The requirement for those providing healthcare to measure outcomes raises the fundamental question of how these should be measured. Both the scale of the low vision population and the different models of care proposed make it a pressing need to determine outcomes using valid and reliable measures. In this study we describe the development and piloting of a questionnaire designed to meet this requirement. The questionnaire was piloted on 56 subjects with age-related macular degeneration (ARMD). Test-retest reliability of the questionnaire was estimated using a further sample of 28 subjects with ARMD. Pilot testing confirmed the feasibility of administering the questionnaire to an elderly population with ARMD. A total of 87% of the sample reported using an LVA (65% on a daily basis), predominantly for a reading task. The number of tasks an LVA was used for, its frequency of use, length of continuous use and ease of use are significantly associated with the rating of an LVA as important/less important (P < 0.0001), but the acuity achieved with the device is not significantly associated with rated importance (P = 0.11), reinforcing doubt about the validity of visual function outcomes. The limitations of this pilot study and earlier case series in describing the outcomes of low vision care are discussed and a randomised controlled trial using a broad range of outcomes is proposed in order to fully describe the effectiveness of low vision rehabilitation and inform the debate about models of care.