878 resultados para Intervertebral disc degeneration
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Mode of access: Internet.
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"COO-1469-0152. File no. 818."
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Endoparasitoid insects introduce maternal factors into the body of their host at oviposition to suppress cellular defences for the protection of the developing parasitoid. We have shown that transient expression of polydnavirus genes from a hymenopteran parasitoid Cotesia rubecula (CrPDV) is responsible for the inactivation of hemocytes from the lepidopteran host Pieris rapae. Since the observed downregulation of CrPDV genes in infected host tissues is not due to cis-regulatory elements at the CrV1 gene locus, we speculated that the termination of CrPDV gene expression may be due to cellular inactivation caused by the CrV1-mediated immune suppression of infected tissues. To test this assumption, we isolated an imaginal disc growth factor (IDGF) that is expressed in fat body and hemocytes, the target of viral infection and expression of CrPDV genes. Time-course experiments showed that the level of P. rapae IDGF is not affected by parasitization and polydnavirus infection. However, the amount of highly expressed genes, such as storage proteins, arylphorin and lipophorin, are significantly reduced following parasitization. (C) 2004 Elsevier Ltd. All rights reserved.
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Purpose: To determine whether the localization of retinal glutamate transporters is affected by retinal ischaemia and whether their ability to transport glutamate decreases with the progression of ischemic retinal and optic nerve degeneration. Methods: Retinal ischemia was induced in rats by acutely increasing the intraocular pressure (IOP, 110 mmHg/60 min). Reperfusion was permitted for periods up to 60 days post-ischemia. Functional evaluation was performed by monitoring the pupil light reflexes (PLRs) and electroretinograms (flash, flicker ERG and oscillatory potentials). Glutamate transporter localization and D-aspartate (glutamate analogue) uptake were assessed by immunohistochemistry. Results: Intense immunoreactivity for the retinal glutamate transporters (GLAST, GLT1, EAAC1 and EAAT5) was observed at all time points after the insult, despite severe retinal degeneration. D-aspartate was also normally accumulated in the ischemic retinas. Ten days post-operatively the PLR ratio (ratio = indirect/direct PLR = 34 +/- 7(.)5%) was significantly less than the pre-operative value (pre-op = 76(.)7 +/- 2 (.)6%, p < 0(.)05). However, 25 and 35 days post-operatively PLR ratios did not differ significantly from pre-operative values (44(.)4 +/- 6(.)9 and 53(.)8 +/- 9(.)6%, p > 0(.)05). Forty-five and 60 days post-operatively the PLR ratio declined again and was significantly lower than the pre-operative value (33(.)8 + 8(.)7 and 26(.)2 + 8(.)9%, p < 0(.)05). Statistical analysis revealed that all tested ERG components had significantly higher values at 32, but not at 42 and 58 days post-operatively when compared to the first time point recorded post-operatively (10 days). Conclusions: While retinal glutamate transport is compromised during an acute ischemic insult, consequent retinal recovery and degeneration are not due to a change in the excitatory amino acid transporter localization or D-aspartate (glutamate analogue) uptake. Rat retina and optic nerve are capable of spontaneous, but temporary, functional recovery after an acute ischemic insult. (C) 2004 Elsevier Ltd. All rights reserved.
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Rising sea temperatures are increasing the incidences of mass coral bleaching (the dissociation of the coral-algal symbiosis) and coral mortality. In this study, the effects of bleaching (induced by elevated light and temperature) on the condition of symbiotic dinoflagellates (Symbiodinium sp.) within the tissue of the hard coral Stylophora pistillata (Esper) were assessed using a suite of techniques. Bleaching of S. pistillata was accompanied by declines in the maximum potential quantum yield of photosynthesis (F-v/F-m, measured using pulse amplitude modulated [PAM] fluorometry), an increase in the number of Sytox-green-stained algae (indicating compromised algal membrane integrity and cell death), an increase in 2',7'-dichlorodihydrofluroscein diacetate (H(2)DCFDA)stained algae (indicating increased oxidative stress), as well as ultrastructural changes (vacuolisation, losses of chlorophyll, and an increase in accumulation bodies). Algae expelled from S. pistillata exhibited a complete disorganisation of cellular contents; expelled cells contained only amorphous material. In situ samples taken during a natural mass coral bleaching event on the Great Barrier Reef in February 2002 also revealed a high number of Sytox-labelled algae cells in symbio. Dinoflagellate degeneration during bleaching seems to be similar to the changes resulting from senescence-phase cell death in cultured algae. These data support a role for oxidative stress in the mechanism of coral bleaching and highlight the importance of algal degeneration during the bleaching of a reef coral.
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Modification of proteins by reactive ethanol metabolites has been known for some time to occur in the liver, the main site of ethanol metabolism. In more recent studies of laboratory animals, similar modifications have been detected in organs with lesser ability to metabolize ethanol, such as skeletal and cardiac muscle and brain. Such modification may alter protein function or form a neoantigen, making it a target for immune attack. We now report an analysis of protein modification derived from ethanol metabolites in human brain tissue by ELISA using adduct-specific antibodies. We obtained autopsy cerebellum samples from 10 alcoholic cerebellar degeneration cases and 10 matched controls under informed written consent from the next of kin and clearance from the UQ Human Ethics Committee. Elevated levels of protein modifications derived from acetaldehyde (unreduced-acetaldehyde and acetaldehyde-advanced glycation end-product adducts), from malondialdehyde (malondialdehyde adducts) and from combined adducts (malondialdehydeacetaldehyde (MAA) adducts) were detected in alcoholic cerebellar degeneration samples when compared to controls. Other adduct types found in liver samples, such as reduced-acetaldehyde and those derived from hydroxyethyl radicals, were not detected in brain samples. This may reflect the different routes of ethanol metabolism in the two tissues. This is the first report of elevated protein modification in alcoholic cerebellar degeneration, and suggests that such modification may play a role in the pathogenesis of brain injury. Supported by NIAAA under grant NIH AA12404 and the NHMRC (Australia) under grant #981723.
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The benefits of Oscillating Disc Cutting (ODC) over all conventional cutting techniques is that it is capable of breaking very hard rock at acceptable-to-good excavation rates with very low cutter forces. This paper outlines that the oscillating cutting action and the water jets as well as the inertial mass all serve to reduce cutter forces.
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Modification of proteins by reactive ethanol metabolites has been known, for some time, to occur in the liver, the main site of ethanol metabolism. More recently, similar modifi cation has been detected in organs with lesser ability to metabolise ethanol such as skeletal and cardiac muscle, and brain. Such modifi cation may alter protein function or form a neoantigen, making it a target for immune attack.
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Background: The MacDQoL is an individualised measure of the impact of macular degeneration (MD) on quality of life (QoL). There is preliminary evidence of its psychometric properties and sensitivity to severity of MD. The aim of this study was to carry out further psychometric evaluation with a larger sample and investigate the measure's sensitivity to MD severity. Methods: Patients with MD (n = 156: 99 women, 57 men, mean age 79 ± 13 years), recruited from eye clinics (one NHS, one private) completed the MacDQoL by telephone interview and later underwent a clinic vision assessment including near and distance visual acuity (VA), comfortable near VA, contrast sensitivity, colour recognition, recovery from glare and presence or absence of distortion or scotoma in the central 10° of the visual field. Results: The completion rate for the MacDQoL items was 99.8%. Of the 26 items, three were dropped from the measure due to redundancy. A fourth was retained in the questionnaire but excluded when computing the scale score. Principal components analysis and Cronbach's alpha (0.944) supported combining the remaining 22 items in a single scale. Lower MacDQoL scores, indicating more negative impact of MD on QoL, were associated with poorer distance VA (better eye r = -0.431 p < 0.001; worse eye r = -0.350 p < 0.001; binocular vision r = -0.419 p < 0.001) and near VA (better eye r -0.326 p < 0.001; worse eye r = -0.226 p < 0.001; binocular vision r = -0.326 p < 0.001). Poorer MacDQoL scores were associated with poorer contrast sensitivity (better eye r = 0.392 p < 0.001; binocular vision r = 0.423 p < 0.001), poorer colour recognition (r = 0.417 p < 0.001) and poorer comfortable near VA (r = -0.283, p < 0.001). The MacDQoL differentiated between those with and without binocular scotoma (U = 1244 p < 0.001). Conclusion: The MacDQoL 22-item scale has excellent internal consistency reliability and a single-factor structure. The measure is acceptable to respondents and the generic QoL item, MD-specific QoL item and average weighted impact score are related to several measures of vision. The MacDQoL demonstrates that MD has considerable negative impact on many aspects of QoL, particularly independence, leisure activities, dealing with personal affairs and mobility. The measure may be valuable for use in clinical trials and routine clinical care. © 2005 Mitchell et al; licensee BioMed Central Ltd.