162 resultados para disc degeneration

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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The anaerobic skin commensal Propionibacterium acnes is an underestimated cause of human infections and clinical conditions. Previous studies have suggested a role for the bacterium in lumbar disc herniation and infection. To further investigate this, five biopsy samples were surgically excised from each of 64 patients with lumbar disc herniation. P. acnes and other bacteria were detected by anaerobic culture, followed by biochemical and PCR-based identification. In total, 24/64 (38%) patients had evidence of P. acnes in their excised herniated disc tissue. Using recA and mAb typing methods, 52% of the isolates were type II (50% of culture-positive patients), while type IA strains accounted for 28% of isolates (42% patients). Type III (11% isolates; 21% patients) and type IB strains (9% isolates; 17% patients) were detected less frequently. The MIC values for all isolates were lowest for amoxicillin, ciprofloxacin, erythromycin, rifampicin, tetracycline, and vancomycin (≤1 mg/L). The MIC for fusidic acid was 1-2 mg/L. The MIC for trimethoprim and gentamicin was 2 to ≥4  mg/L. The demonstration that type II and III strains, which are not frequently recovered from skin, predominated within our isolate collection (63%) suggests that the role of P. acnes in lumbar disc herniation should not be readily dismissed.

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To evaluate the effect of mass transfer limitations in the three-phase oxidation of cinnamyl alcohol carried out in toluene and an ionic liquid (1-butyl-3-methyl-imidazolium bis(trifluoromethylsulphonyl)imide), studies have been performed in a rotating disc reactor and compared with those carried out in a stirred tank reactor where mass transfer effects are considered negligible. High catalyst efficiencies are found in the stirred tank reactor with the use of both ionic liquid and toluene, although there is a decrease in rate for the ionic liquid reactions. In contrast, internal pore diffusion limits the reaction in both solvents in the rotating disc reactor. This mass transfer resistance reduces the problem of overoxidation of the metal surface when the reaction is carried out in toluene, leading to significantly higher rates of reaction than expected, although at the cost of decreased selectivity.

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Purpose: Age related macular degeneration (AMD) is a common cause of severe vision loss. Identification of genes involved in AMD will facilitate early detection and ultimately help to identify pathways for treatment for this disorder. The A16,263G mutation in the HEMICENTIN-1 gene produces a non-conservative substitution of arginine for glutamine at codon 5345 which has been implicated in familial AMD. The aim of this study is to develop a rapid diagnostic assay for the detection of this mutation and to evaluate its frequency in a sample of AMD patients. Methods: A primer probe set was designed from exon 104 of the HEMICENTIN-1 gene to differentiate between mutant and wild type alleles. A region spanning the mutation was amplified by PCR using a LightCycler (Roche Diagnostic). The mutation was then detected by melt curve analysis of the hybrid formed between the PCR product and a specific fluorescent probe. The frequency of the mutation within the Northern Ireland population was evaluated by assaying 508 affected AMD patients, 25 possibly affected and 163 controls. Results: This assay clearly discriminates between the A16,263G mutant and wild type HEMICENTIN-1 alleles. The wild type sequence has a single base mismatch with the probe which decreases the stability of the hybrid, resulting in a lower TM (TM=51.27 °C) than that observed for the perfectly matched mutant allele (TM=59.9 °C). The mutant allele was detected in only one of the 696 subjects, an affected AMD patient. Conclusions: We describe a rapid assay for the genotyping of the Gln5345Arg mutation using real-time fluorescence PCR to facilitate rapid processing of samples through combined amplification and detection steps. These characteristics are suitable for a clinical setting where high throughput diagnostic procedures are required. The frequency of this mutation within the Northern Ireland population has been estimated at 0.2%, concurring with previous findings that this mutation is a rare variant associated with AMD. A rapid diagnostic assay will facilitate a reliable and convenient evaluation of the frequency of the Gln5345Arg mutation and its association with AMD within other populations.

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Aim: To study the relation between visual impairment and ability to care for oneself or a dependant in older people with age related macular degeneration (AMD). Method: Cross sectional study of older people with visual impairment due to AMD in a specialised retinal service clinic. 199 subjects who underwent visual function assessment (fully corrected distance and near acuity and contrast sensitivity in both eyes), followed by completion of a package of questionnaires dealing with general health status (SF36), visual functioning (Daily Living Tasks Dependent on Vision, DLTV) and ability to care for self or provide care to others. The outcome measure was self reported ability to care for self and others. Three levels of self reported ability to care were identified—inability to care for self (level 1), ability to care for self but not others (level 2), and ability to care for self and others (level 3). Results: People who reported good general health status and visual functioning (that is, had high scores on SF36 and DLTV) were more likely to state that they were able to care for self and others. Similarly people with good vision in the better seeing eye were more likely to report ability to care for self and others. People with a distance visual acuity (DVA) worse than 0.4 logMAR (Snellen 6/15) had less than 50% probability of assigning themselves to care level 3 and those with DVA worse than 1.0 logMAR (Snellen 6/60) had a probability of greater than 50% or for assigning themselves to care level 1. Regression analyses with level of care as the dependent variable and demographic factors, DLTV subscales, and SF36 dimensions as the explanatory variables confirmed that the DLTV subscale 1 was the most important variable in the transition from care level 3 to care level 2. The regression analyses also confirmed that the DLTV subscale 2 was the most important in the transition from care level 3 to care level 1. Conclusions: Ability to care for self and dependants has a strong relation with self reported visual functioning and quality of life and is adversely influenced by visual impairment. The acuity at which the balance of probability shifts in the direction of diminished ability to care for self or others is lower than the level set by social care agencies for provision of support. These findings have implications for those involved with visual rehabilitation and for studies of the cost effectiveness of interventions in AMD.

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We present high-resolution (R = lambda/Deltalambda similar to 40 000) Ca II K interstellar observations (lambda(air) = 3933.66Angstrom) towards 88 mainly B-type stars, of which 74 are taken from the Edinburgh-Cape or Palomar-Green surveys, and 81 have > 25degrees. The majority of the data come from previously existing spectroscopy, although also included are 18 new observations of stars with echelle spectra taken with UVES on the Very Large Telescope UT2 (Kueyen). Some 49 of the sample stars have distance estimates above the Galactic plane (z) greater than or equal to 1 kpc, and are thus good probes of the halo interstellar medium. Of the 362 interstellar Ca K components that we detect, 75 (21 per cent) have absolute values of their LSR velocity values exceeding 40 km s(-1). In terms of the deviation velocity for the sightlines with distance estimates, 46/273 (17 per cent) of components have velocity values exceeding those predicted by standard Galactic rotation by more than 40 km s(-1). Combining this data set with previous observations, we find that the median value of the reduced equivalent width (REW) of stars with z greater than or equal to 1 kpc (EW x sin ) is similar to 115 mAngstrom (n = 80), similar to that observed in extragalactic sightlines by Bowen. Using data of all z distances, the REW at infinity is found to be similar to 130 mAngstrom, with the scaleheight (1) of the Ca II K column density distribution being;z 800 pc (n = 196) and reduced column density at infinity of log[N(Ca II K) cm(-2)] similar to 12.24. This implies that similar to30 per cent of Ca II K absorption occurs at distances exceeding similar to1 kpc. For nine sightlines, with distance exceeding 1 kpc and with a companion object within 5degrees, we find that all but two have values of Ca II reduced equivalent width the same to within similar to20 per cent, when the REW of the nearest object is extrapolated to the distance of the further of the pair, and assuming 1 = 800 pc. For 29 of our sightlines with z greater than or equal to 1 kpc and a H I detection from the Leiden-Dwingeloo survey (beamsize of 0.5degrees), we find log(N(Ca II K)IN(H I)) ranging from -7.4 to - 8.4. Values of the Ca II K abundance relative to neutral hydrogen (log[N(Ca II K) cm(-2)] - log[N(H I) cm(-2)]) are found to be more than similar to0.5 dex higher in stars with distances exceeding approximate to100 pc, when compared with the (log[N(Ca II K) cm(-2)] -log[N(H-tot) cm(-2)]) values found in nearby sightlines such as those in Wakker & Mathis (2000). Finally, stellar Ca II K equivalent widths of the sample are determined for 26 objects.

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We compare existing high spectral resolution (R = lambda/Deltalambda similar to 40 000) Ca II Kobservations (lambda(air) = 3933.66 Angstrom) towards 88 mainly B-type stars, and new observations taken using the Intermediate dispersion Spectrograph and Imaging System (ISIS) on the William Herschel Telescope at R similar to 10 000 towards three stars taken from the Palomar-Green Survey, with 21-cm HI emission-line profiles, in order to search for optical absorption towards known intermediate- and high-velocity cloud complexes. Given certain assumptions, limits to the gas phase abundance of Ca II are estimated for the cloud components. We use the data to derive the following distances from the Galactic plane (z). (i) Tentative lower z-height limits of 2800 and 4100 pc towards complex C using lack of absorption in the spectra of HD341617 and PG 0855 + 294, respectively. (ii) A weak lower z-height of 1400 pc towards complex WA-WB using lack of absorption in EC 09470-1433 and a weak lower limit of 2470 pc using lack of absorption in EC 09452-1403. (iii) An upper z- height of 2470 pc towards a southern intermediate- velocity cloud (IVC) with v(LSR) = -55 km s(-1) using PG 2351 + 198. (iv) Detection of a possible IVC in Ca II absorption at v(LSR) = +52 km s(-1) using EC 20104-2944. No associated HI in emission is detected. At this position, normal Galactic rotation predicts velocities of up to similar to+ 25 km s(-1). The detection puts an upper z-height of 1860 pc to the cloud. (v) Tentative HI and Ca II K detections towards an IVC at similar to+70 km s(-1) in the direction of high-velocity cloud (HVC) complex WE, sightline EC 06387-8045, indicating that the IVC may be at a z-height lower than 1770 pc. (vi) Detection of Ca II K absorption in the spectrum of PG 0855 + 294 in the direction of IV20, indicating that this IVC has a z-height smaller than 4100 pc. (vii) A weak lower z-height of 4300 pc towards a small HVC with v(LSR) = +115 km s(-1) at l, b = 200degrees, + 52degrees, using lack of absorption in the Ca II K spectrum of PG 0955 + 291.

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We present Ca II K (lambda(air) = 3933.661 angstrom) interstellar observations towards 20 early-type stars, to place lower distance limits to intermediate- and high-velocity clouds (IHVCs) in their lines of sight. The spectra are also employed to estimate the Ca abundance in the low-velocity gas towards these objects, when combined with Leiden-Dwingeloo 21-cm HI survey data of spatial resolution 0 degrees.5. Nine of the stars, which lie towards IHVC complexes H, K and gp, were observed with the intermediate dispersion spectrograph on the Isaac Newton Telescope at a resolution R = lambda/Delta lambda of 9000 (similar to 33 km s(-1)) and signal-to-noise ratio (S/N) per pixel of 75-140. A further nine objects were observed with the Utrecht Echelle Spectrograph on the William Herschel Telescope at R = 40 000 (similar to 7.5 km s(-1)) and S/N per pixel of 10-25. Finally, two objects were observed in both Ca II K and Na I D lines using the 2D COUDE on the McDonald 2.7-m telescope at R = 35 000 (similar to 8.5 km s(-1)). The abundance of Ca II K {log(10)(A) = log(10)[N(Ca II K)]-log(10)[N(HI)]} plotted against HI column density for the objects in the current sample with heights above the Galactic plane (z) exceeding 1000 pc is found to obey the Wakker & Mathis (2000) relation. Also, the reduced column density of Ca II K as function of z is consistent with the larger sample taken from Smoker et al. (2003). Higher S/N observations than those previously taken towards HVC complex H stars HD 13256 and HILT 190 reinforce the assertion that this lies at a distance exceeding 4000 pc. No obvious absorption is detected in observations of ALS 10407 and HD 357657 towards IVC complex gp. The latter star has a spectroscopically estimated distance of similar to 2040 pc, although this was derived assuming the star lies on the main sequence and without any reddening correction being applied. Finally, no Ca II K absorption is detected towards two stars along the line of sight to complex K, namely PG 1610+529 and PG 1710+490. The latter is at a distance of similar to 700 pc, hence placing a lower distance limit to this complex, where previously only an upper distance limit of 6800 pc was available.

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PURPOSE. To assess the prevalence of age-related macular degeneration (AMD) in a rural population in Northern India. METHODS. In a pilot feasibility study, 1443 people (median age, 60 years; 52% women), were identified from enumeration of the 50+ age group in 11 randomly sampled villages from a rural, periurban district of Haryana, Northern India. Of those identified, 87% attended an eye examination that included digital fundus photography. Fundus images were graded at a single reading center using definitions from the Wisconsin Age-Related Maculopathy Grading System. RESULTS. Fundus photographs were available for 1101 participants. Overall, 28.8% of participants had ungradable fundus images due to cataract. Including all with ungradable images in the denominator, the prevalence of soft drusen was 34.0% (95% confidence interval [CI] 26.1–42.9); of soft indistinct drusen, 2.2% (95% CI, 1.1–4.4); and of pigmentary irregularities, 10.8% (95% CI, 7.1–16.1). There were 15 (1.4%) cases of late-stage AMD (95% CI, 0.8–2.3) with the prevalence rising from 0.4% in the 50- to 59-year age range to 4.6% in those aged 70 years or older. CONCLUSIONS. Drusen and pigmentary irregularities are common among the rural northern Indian population. The prevalence of late AMD is similar to that encountered in Western settings and is likely to contribute significantly to the burden of vision loss in older people in the developing world.