1,628 research outputs found

    Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats

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    Background: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. Methods: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. Results: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. Conclusions: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear

    Contrasting styles of alteration and metamorphism in shear zones at Wawa, Ontario.

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    Petrographic and chemical analysis of sheared rocks from seven narrow deformation zones in Archean-age rocks near Wawa, Ontario reveal different styles of alteration and deformation. The strained rocks are classified into protomylonite, mylonite and ultramylonite using feldspar grain-size measurements and clast/matrix ratios. Hydrothermal alteration and gold mineralization result in complex chemical patterns in some of the shear zones. Typically mineralizing fluids add SiO\sb2, alkalis, copper, gold and arsenic. Early alterations are overprinted by the chemical changes accompanying formation of mylonites and post-deformation alterations are generally constrained to the most deformed rocks. Evidence of multiple deformation and alteration events in the study area leads to a proposed model of the temporal relationship among the deformation and mineralization events. The northeast-striking shear zones show evidence of an early mineralization that is disturbed and altered during mylonitization. In some cases the shear zones act as conduits for a later mineralizing event. A set of northwest-striking shear zones offset the northeast-striking set. The northwest set show a less complex history with a single mineralizing event following deformation. (Abstract shortened by UMI.) Source: Masters Abstracts International, Volume: 31-03, page: 1174. Adviser: W. H. Blackburn. Thesis (M.Sc.)--University of Windsor (Canada), 1992

    Assessing the Viability of the EQ-5D as Part of a Battery of Outcomes in Elderly Total Knee Arthroplasty Patients: A Comparison of Generic, Condition-Specific, and Preference-Based Patient-Reported Outcome Measures

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    Background In the current economic climate it has become increasingly important to evaluate the effectiveness of expensive procedures such as total knee arthroplasties (TKAs). Patient-reported outcome measures, such as generic and condition-specific profile measures, are popular ways of determining outcomes. However, these cannot be used reliably for the purpose of economic evaluations. The EQ-5D, designed for cost-utility analysis, could offer potential advantages to outcome measurement; however, little is known about the viability and performance of this measure in more elderly (_ 75 years) patient cohorts. Aims The aim of this study was to assess the viability of the EQ-5D for use in the evaluation of TKA and to provide justification for its continued inclusion in the clinical audit of patients undergoing arthroplasty in a large general hospital. Methods Seven-hundred and seventy-nine consecutive patients undergoing TKA participated in this study. Self-report audit questionnaire booklets were administered at baseline (during a pre-admission clinic appointment) and six months post-operatively (postally). Booklets comprised of the Oxford Knee Scale (OKS;), 12-dimension Short Form (SF-12;), and the EQ-5D (). Results Two-hundred and forty-six subjects completed both the baseline and follow-up audit surveys. Correlations were strongest between the EQ-5D and OKS instruments (baseline: Tb=-0.58; p0.01; follow-up: Tb=-0.41; p0.01),.. The EQ-5D displayed large effect sizes (d=0.94) and was able to detect clinically important HRQoL improvements (ROC P-value=0.65; CI0.08; p0.001), discriminate those patients who were experiencing poorer pre-operative health (p0.001), and detect those who deteriorated post-operatively (p0.001). Adequate reliability (Cronbach's =0.79) of the EQ-5D instrument was seen post-operatively as well. Conclusions Results from this study reveal that the EQ-5D instrument shows good responsiveness to health changes in elderly TKA patients post-operatively. Its correlations with the OKS, detection of poorer pre-operative health, and detection of deterioration post-operatively also suggest good validity for the EQ-5D in this cohort. Finally, the relatively large reliability statistic post-operatively supports the use of the EQ-5D in audits. Together, these findings support the continued use of the EQ-5D instrument in future arthroplasty audits and provide evidence that it is viable for the use in cost-utility analysis.sch_phyunpub2424unpu

    Total knee arthroplasty in patients with severe obesity:outcomes of standard keeled tibial components versus stemmed universal base plates

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    Background: Patients with severe obesity [body mass index (BMI) ≥ 40 kg/m2] potentially overload the tibial component after total knee arthroplasty (TKA), risking tibial subsidence. Using a cemented single-radius cruciate-retaining TKA design, this study compared the outcomes of two tibial baseplate geometries in patients with BMI ≥ 40 kg/m2: standard keeled (SK) or universal base plate (UBP), which incorporates a stem. Methods: This was a retrospective, single-centre cohort study with minimum 2 years follow-up of 111 TKA patients with BMI ≥ 40 kg/m2: mean age 62.2 ± 8.0 (44–87) years, mean BMI 44.3 ± 4.6 (40–65.7) kg/m2 and 82 (73.9%) females. Perioperative complications, reoperations, alignment and patient-reported outcomes (PROMS): EQ-5D, Oxford Knee Score (OKS), Visual Analogue Scale (VAS) pain score and satisfaction were collected preoperatively, and at 1 year and final follow-up postoperatively. Results: Mean follow-up was 4.9 years. SK tibial baseplates were performed in 57 and UBP in 54. There were no significant differences in baseline patient characteristics, post-operative alignment, post-operative PROMs, reoperations or revisions between the groups. Three early failures requiring revision occurred: two septic failures in the UBP group and one early tibial loosening in the SK group. Five-year Kaplan–Meier survival for the endpoint mechanical tibial failure was SK 98.1 [94.4–100 95% confidence interval (CI)] and UBP 100% (p = 0.391). Overall varus alignment of the limb (p = 0.005) or the tibial component (p = 0.031) was significantly associated with revision and return to theatre. Conclusions: At early to mid-term follow-up, no significant differences in outcomes were found between standard and UBP tibial components in patients with BMI ≥ 40 kg/m2. Varus alignment of either tibial component or the limb was associated with revision and return to theatre.</p

    Eye See Eye Learn The Benefit of Comprehensive Eye Examinations for Preschoolers

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    Objective: Undetected vision problems in children can lead to permanent vision loss, a condition known as amblyopia. Early detection and treatment of the causes of amblyopia may prevent this vision loss. The objective of this paper is to look for evidence that comprehensive eye examinations upon entry to junior Kindergarten are an effective way to identify and treat vision problems early. methods: Relevant peer-reviewed publications on amblyopia and the importance of comprehensive eye examinations were reviewed. Specific areas investigated include: the prevalence and causes of amblyopia; impact of vision problems on child development and education; impact of amblyopia and/or strabismus on quality of life; and the cost effectiveness of treating amblyopia. The validity of vision screening compared to a comprehensive eye examination was also reviewed. Synthesis:The review suggests that without a complete eye examination many eye or vision problems remain undetected at school entry. Left uncorrected these problems negatively impact child development, education and quality of life. Reduced vision due to amblyopia also restricts future employment opportunities and increases the risk of bilateral visual impairment in adulthood. Examination procedures with high sensitivity and specificity are required to accurately detect these problems. Studies show that amblyopia treatment initiated at an early age is one of the most cost-effective of all health interventions. Conclusion: There is good evidence in the literature that a full eye examination is critical to detect all cases of amblyopia. This and other visual problems can be detected and managed at an early age, which leads to better visual quality of life and economical outcomes. The Eye See Eye Learn program offers the “gold standard” of eye care
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