68 research outputs found

    Identification and characterization of a Pi isoform of glutathione S-transferase (GSTP1) as a zeaxanthin-binding protein in the macula of the human eye

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    Journal ArticleUptake, metabolism, and stabilization of xanthophyll carotenoids in the retina are thought to be mediated by specific xanthophyll-binding proteins (XBPs). A membrane-associated XBP was purified from human macula using ion-exchange chromatography followed by gel-exclusion chromatography. Two-dimensional gel electrophoresis showed a prominent spot of 23 kDa and an isoelectric point of 5.7. Using mass spectral sequencing methods and the public NCBI database, it was identified as a Pi isoform of human glutathione S-transferase (GSTP1). Dietary (3R,3'R)-zeaxanthin displayed the highest affinity with an apparent Kd of 0.33 microm, followed by (3R,3'S-meso)-zeaxanthin with an apparent Kd of 0.52 microm. (3R,3'R,6'R)-Lutein did not display any high-affinity binding to GSTP1. Other human recombinant glutathione S-transferase (GST) proteins, GSTA1 and GSTM1, exhibited only low affinity binding of xanthophylls. (3R,3'S-meso)-Zeaxanthin, an optically inactive nondietary xanthophyll carotenoid present in the human macula, exhibited a strong induced CD spectrum in association with human macular XBP that was nearly identical to the CD spectrum induced by GSTP1. Like-wise, dietary (3R,3'R)-zeaxanthin displayed alterations in its CD spectrum in association with GSTP1 and XBP. Other mammalian xanthophyll carrier proteins such as tubulin, high-density lipoprotein, low-density lipoprotein, albumin, and beta-lactoglobulin did not bind zeaxanthins with high affinity, and they failed to induce or alter xanthophyll CD spectra to any significant extent. Immunocytochemistry with an antibody to GSTP1 on human macula sections showed highest labeling in the outer and inner plexiform layers. These results indicate that GSTP1 is a specific XBP in human macula that interacts with (3R,3'S-meso)-zeaxanthin and dietary (3R,3'R)-zeaxanthin in contrast to apparently weaker interactions with (3R,3'R,6'R)-lutein

    HPLC measurement of ocular carotenoid levels in human donor eyes in the lutein supplementation era.

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    Journal ArticlePURPOSE: A substantial proportion of the population at risk for visual loss from age-related macular degeneration consumes supplements containing high doses of lutein, but clinical studies to date have shown only modest and variable increases in macular carotenoid pigments in response to supplementation. To determine whether lutein supplementation can indeed alter ocular carotenoid levels, the authors chemically measured levels of lutein, zeaxanthin, and their metabolites in the macula, peripheral retina, and lens of 228 eyes from 147 human donors and correlated these results with retrospective supplement histories from families of selected members of the study population. METHODS: Lenses and circular punches of macula (4-mm diameter) and equatorial peripheral retina (8-mm diameter) were dissected from donor eyes free of ocular disease procured from the local eye bank. The amounts of lutein, zeaxanthin, meso-zeaxanthin, and 3'-oxolutein were determined by HPLC with photodiode array and mass spectral detection. RESULTS: Eighteen percent of eyes from donors age 48 and older had unusually high levels (66.3 +/- 15.1 ng) of macular carotenoids that were three times the rest of the older population's mean level (23.0 + 12.1 ng; P < 0.001). Carotenoid levels in these outliers were also unusually high in the lens and in the peripheral retina. Similar outliers were not present in donors younger than 48. Most of these outliers regularly consumed high-dose lutein supplements before death. Lutein supplementation was uncommon in older donors whose macular carotenoids were in the normal range. CONCLUSIONS: The presence of unusually high levels of macular carotenoids in older donors who were regularly consuming high-dose lutein supplements supports the hypothesis that long-term lutein supplementation can raise levels of macular pigment. Elevated carotenoid levels in the peripheral retina and lens in these same donors could have important implications for understanding why some clinical methods of macular pigment measurement have had difficulty detecting robust and consistent responses in carotenoid supplementation trials

    Geocell Reinforced Flexible Pavement: Analysis of Strain Induced in Geocell vis-a-vis Thin and Thick-walled Cylinder Theory

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    Vertical pressure from vehicles on pavement reinforced with geocell develops radial and hoop stresses on geocell walls. Thin-walled cylinder theory is used to estimate the strain induced in geocell by some researchers. It is observed that thin-walled cylinder theory significantly overestimates induced strain when compared with experimental values. This paper presents non-accounted effect of lateral resistance mobilized due to geocell infill soil in computing strain by thin-walled cylinder theory. It is observed that computed strain values using thin-walled cylinder theory accounting lateral resistance match well with experimental results reported in literature. Equivalent thickness (teq) of geocell is then back-calculated by matching the experimental strain values with computed strain values using thin-walled cylinder theory accounting lateral resistance. As the thickness of geocell increases in the form of teq, thick-walled cylinder theory is also studied to analyze the strain induced in the geocell. Combined analysis is then carried out by modifying thick-walled cylinder theory equations using teq derived from thin-walled cylinder theory, and new factor named merging factor (M.F.) is introduced.&nbsp; Results of thick-walled cylinder theory with M.F. match well with experimental strain values reported in literature. Strain computed using modified thin-walled cylinder theory is validated with laboratory results of other researchers

    Crack Propagation Analysis of Synthetic vs. Steel vs. Hybrid Fibre-Reinforced Concrete Beams Using Digital Image Correlation Technique

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    Improvement in fracture behaviour of fibre-reinforced concrete (FRC) due to the inclusion of various types and combinations of fibres is widely reported. The fracture behaviour of FRC needs to be fully understood for the optimum use of these fibres in structural elements. Fracture behaviours of synthetic fibre-reinforced concrete (SynFRC), hybrid fibre-reinforced concrete (HFRC) and steel fibre-reinforced concrete (SFRC) are investigated in this study using digital image correlation (DIC) technique. This work focuses on improvement in the structural performance of FRC through a comprehensive study of the change in the crack length, crack opening and fracture process zone (FPZ) due to different fibres addition and their combinations. Three distinct fibre dosages of 0.50%, 0.75%, and 1.00%, of macro-polyolefin fibres, hooked end steel fibres and their hybrid combination are regarded as research parameters. Test outcomes indicate that HFRC offers higher post-cracking resistance when compared to SynFRC. SFRC showcases superior fracture performance than that of HFRC and SynFRC. Full-field strain measurements from DIC are used to measure the crack openings at different load levels during the fracture tests. Results of DIC analysis show good agreement with experimental measurements. Continuous monitoring of strain contours using DIC reveals the effective engagement of fibres along the depth at higher dosages for HFRC when compared to that of SynFRC. Also, HFRC had longer cracks than SFRC at a particular load

    Comparative study of hyperbaric 0.5% bupivacaine and hyperbaric 0.5% bupivacaine with low dose dexmedetomidine in spinal anaesthesia

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    Background: Spinal anaesthesia remains one of the basic techniques in the arsenal of modern anaesthesiology despite the waxing and waning of its popularity over last 100 years since its introduction into clinical practice.It avoids biochemical and metabolic changes consequent to the stress of general anesthesia for surgery as well as provides near optimal conditions for surgery. In present study, we tried to study effectiveness of intrathecal 0.5% heavy bupivacaine alone with Dexmedetomidine as an adjuvant to intrathecal 0.5% heavy bupivacaine for lower limb and lower abdominal surgeries.Methods: The present study was conducted in the department of anaesthesiology from December 2011 to September 2013.This study was a prospective, randomised controlled, single blind, study conducted in 100 patients of ASA grade I and II undergoing elective surgeries under spinal anaesthesia. The patients were divided randomly into two groups, containing 50 patients in each group. Dosages of drugs selected are divided as Group B: Patients received 3 ml of 0.5% hyperbaric bupivacaine (15mg) and Group BD: Patients received 3 ml of 0.5% hyperbaric bupivacaine (15mg) plus 10 µg Dexmedetomidine. Spinal block characteristics, Mean arterial pressure, Mean pulse rate, sedation and side effects were studied during intra-operative and postoperative period.Results: It was found from present study that in Dexmedetomidine group time to reach T10 sensory blockade and complete motor blockade was earlier and a higher level of sensory blockade compared to control group achieved. Duration of sensory, motor blockade and duration of analgesia was significantly prolonged in the Dexmedetomidine group compared to the control group. Hemodynamic parameters were preserved both intra-operatively and postoperatively. However there were a small percentage of patients who developed hypotension and bradycardia which were easily managed without any untoward effect. Hence Dexmedetomidine is a better neuraxial adjuvant for providing early onset of sensory and motor blockade, prolonged sensory blockade and post operative analgesia and adequate sedation.Conclusions: Intrathecal low dose Dexmedetomidine in a dose of 10µg along with 0.5% hyperbaric bupivacaine is an addition into anaesthesiologist's armamentarium for spinal anaesthesia in patients undergoing elective lower abdominal and lower limb surgeries

    Poboljšan postupak sinteze nekih novih 1,3-diaril-2-propen-1-ona koristeći PEG-400 kao reciklirajuće otapalo i njihovo antimikrobno vrednovanje

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    A simple and convenient route is described for the synthesis of novel hetero 1,3-diaryl-2-propen-1-ones (chalcones) by using recyclable poly PEG-400 as an alternative reaction solvent. The reaction is clean with excellent yield, shorter reaction time and reduces the use of volatile organic compounds (VOCs). All the synthesized compounds were evaluated for their antimicrobial activities against several pathogenic representatives.Opisana je jednostavna i pogodna metoda sinteze novih hetero 1,3-diaril-2-propen-1-ona (kalkona) koristeći poli(etilenglikol) (PEG-400) kao alternativno otapalo. Reakcija je jednoznačna, a uporaba hlapljivih organskih otapala je smanjena. Iskorištenja na produktima su visoka, a reakcijska vremena kraća. Svi sintetizirani spojevi testirani su na antimikrobno djelovanje na nekoliko patogenih mikroorganizama

    Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

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    Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p&lt;0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (&lt;1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (&lt;1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

    Autologous chondrocyte implantation in the knee : systematic review and economic evaluation

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    Background: The surfaces of the bones in the knee are covered with articular cartilage, a rubber-like substance that is very smooth, allowing frictionless movement in the joint and acting as a shock absorber. The cells that form the cartilage are called chondrocytes. Natural cartilage is called hyaline cartilage. Articular cartilage has very little capacity for self-repair, so damage may be permanent. Various methods have been used to try to repair cartilage. Autologous chondrocyte implantation (ACI) involves laboratory culture of cartilage-producing cells from the knee and then implanting them into the chondral defect. Objective: To assess the clinical effectiveness and cost-effectiveness of ACI in chondral defects in the knee, compared with microfracture (MF). Data sources: A broad search was done in MEDLINE, EMBASE, The Cochrane Library, NHS Economic Evaluation Database and Web of Science, for studies published since the last Health Technology Assessment review. Review methods: Systematic review of recent reviews, trials, long-term observational studies and economic evaluations of the use of ACI and MF for repairing symptomatic articular cartilage defects of the knee. A new economic model was constructed. Submissions from two manufacturers and the ACTIVE (Autologous Chondrocyte Transplantation/Implantation Versus Existing Treatment) trial group were reviewed. Survival analysis was based on long-term observational studies. Results: Four randomised controlled trials (RCTs) published since the last appraisal provided evidence on the efficacy of ACI. The SUMMIT (Superiority of Matrix-induced autologous chondrocyte implant versus Microfracture for Treatment of symptomatic articular cartilage defects) trial compared matrix-applied chondrocyte implantation (MACI®) against MF. The TIG/ACT/01/2000 (TIG/ACT) trial compared ACI with characterised chondrocytes against MF. The ACTIVE trial compared several forms of ACI against standard treatments, mainly MF. In the SUMMIT trial, improvements in knee injury and osteoarthritis outcome scores (KOOSs), and the proportion of responders, were greater in the MACI group than in the MF group. In the TIG/ACT trial there was improvement in the KOOS at 60 months, but no difference between ACI and MF overall. Patients with onset of symptoms < 3 years’ duration did better with ACI. Results from ACTIVE have not yet been published. Survival analysis suggests that long-term results are better with ACI than with MF. Economic modelling suggested that ACI was cost-effective compared with MF across a range of scenarios. Limitations: The main limitation is the lack of RCT data beyond 5 years of follow-up. A second is that the techniques of ACI are evolving, so long-term data come from trials using forms of ACI that are now superseded. In the modelling, we therefore assumed that durability of cartilage repair as seen in studies of older forms of ACI could be applied in modelling of newer forms. A third is that the high list prices of chondrocytes are reduced by confidential discounting. The main research needs are for longer-term follow-up and for trials of the next generation of ACI. Conclusions: The evidence base for ACI has improved since the last appraisal by the National Institute for Health and Care Excellence. In most analyses, the incremental cost-effectiveness ratios for ACI compared with MF appear to be within a range usually considered acceptable. Research is needed into long-term results of new forms of ACI

    Autologous chondrocyte implantation in the knee: systematic review and economic evaluation

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