61 research outputs found

    Total Synthesis and Evaluation of c26-Hydroxyepothilone D Derivatives for Photoaffinity Labeling of β-Tubulin

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    Three photaffinity labeled derivatives of epothilone D were prepared by total synthesis, using efficient novel asymmetric synthesis methods for the preparation of two important synthetic building blocks. The key step for the asymmetric synthesis of (S,E)-3-(tert-butyldimethylsilyloxy)-4-methyl-5-(2-methylthiazol-4-yl)pent-4-enal involved a ketone reduction with (R)-Me-CBS-oxazaborolidine. For the synthesis of (5S)-5,7-di-[(tert-butyldimethylsilyl)oxy]-4,4-dimethylheptan-3-one an asymmetric Noyori reduction of a β-ketoester was employed. The C26 hydroxyepothilone D derivative was constructed following a well-established total synthesis strategy and the photoaffinity labels were attached to the C26 hydroxyl group. The photoaffinity analogues were tested in a tubulin assembly assay and for cytotoxicity against MCF-7 and HCT-116 cancer cell lines. The 3- and 4-azidobenzoic acid analogues were found to be as active as epothilone B in a tubulin assembly assay, but demonstrated significantly reduced cellular cytotoxicity compared to epothilone B. The benzophenone analogue was inactive in both assays. Docking and scoring studies were conducted that suggested that the azide analogues can bind to the epothilone binding site, but that the benzophenone analogue undergoes a sterically driven ligand rearrangement that interrupts all hydrogen bonding and therefore protein binding. Photoaffinity labeling studies with the 3-azidobenzoic acid derivative did not identify any covalently labeled peptide fragments, suggesting that the phenylazido side chain was predominantly solvent-exposed in the bound conformation

    Subsequent Surgery After Revision Anterior Cruciate Ligament Reconstruction: Rates and Risk Factors From a Multicenter Cohort

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    BACKGROUND: While revision anterior cruciate ligament reconstruction (ACLR) can be performed to restore knee stability and improve patient activity levels, outcomes after this surgery are reported to be inferior to those after primary ACLR. Further reoperations after revision ACLR can have an even more profound effect on patient satisfaction and outcomes. However, there is a current lack of information regarding the rate and risk factors for subsequent surgery after revision ACLR. PURPOSE: To report the rate of reoperations, procedures performed, and risk factors for a reoperation 2 years after revision ACLR. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 1205 patients who underwent revision ACLR were enrolled in the Multicenter ACL Revision Study (MARS) between 2006 and 2011, composing the prospective cohort. Two-year questionnaire follow-up was obtained for 989 patients (82%), while telephone follow-up was obtained for 1112 patients (92%). If a patient reported having undergone subsequent surgery, operative reports detailing the subsequent procedure(s) were obtained and categorized. Multivariate regression analysis was performed to determine independent risk factors for a reoperation. RESULTS: Of the 1112 patients included in the analysis, 122 patients (11%) underwent a total of 172 subsequent procedures on the ipsilateral knee at 2-year follow-up. Of the reoperations, 27% were meniscal procedures (69% meniscectomy, 26% repair), 19% were subsequent revision ACLR, 17% were cartilage procedures (61% chondroplasty, 17% microfracture, 13% mosaicplasty), 11% were hardware removal, and 9% were procedures for arthrofibrosis. Multivariate analysis revealed that patients aged <20 years had twice the odds of patients aged 20 to 29 years to undergo a reoperation. The use of an allograft at the time of revision ACLR (odds ratio [OR], 1.79; P = .007) was a significant predictor for reoperations at 2 years, while staged revision (bone grafting of tunnels before revision ACLR) (OR, 1.93; P = .052) did not reach significance. Patients with grade 4 cartilage damage seen during revision ACLR were 78% less likely to undergo subsequent operations within 2 years. Sex, body mass index, smoking history, Marx activity score, technique for femoral tunnel placement, and meniscal tearing or meniscal treatment at the time of revision ACLR showed no significant effect on the reoperation rate. CONCLUSION: There was a significant reoperation rate after revision ACLR at 2 years (11%), with meniscal procedures most commonly involved. Independent risk factors for subsequent surgery on the ipsilateral knee included age <20 years and the use of allograft tissue at the time of revision ACLR

    Prevalence and morphology of coronary artery ectasia with dual-source CT coronary angiography

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    To assess the prevalence and morphological characteristics of coronary artery ectasia (CAE) with CT coronary angiography (CTCA) in comparison to conventional catheterangiography (CCA). Dual-source CTCA examinations from 677 consecutive patients (223 women; median age 57 years) were retrospectively evaluated by two blinded observers for the presence of CAE defined as a diameter enlargement >/=1.5 times the diameter of adjacent normal coronary segments. Vessel diameters and contrast attenuation within and proximal to ectatic segments were measured. CCA was used to compare measurements obtained from CTCA with the coronary flow velocity by using the thrombolysis in myocardial infarction (TIMI) frame count. CTCA identified CAE in 20 of 677 (3%) patients. CCA was performed in ten of these patients. CAE diameter measurements with CTCA (10.0 +/- 5.4 mm) correlated significantly (r = 0.92, p < 0.001) with the CCA measurements (8.8 +/- 4.9 mm), but had higher diameters (levels of agreement: -1.0 to 3.4 mm). Contrast attenuation was significantly lower in the ectatic (343 +/- 63 HU) than in the proximal (394 +/- 60 HU) segments (p < 0.01). The attenuation difference significantly correlated with the CAE ratio (r = 0.67, p < 0.01) and the TIMI frame count (r = 0.58, p < 0.05). The prevalence of CAE in a population examined by CTCA is around 3%. Contrast attenuation measurements with CTCA correlate well with the flow alterations assessed with CCA

    Grand Challenges in global eye health: a global prioritisation process using Delphi method

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    Background We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods Drawing on methods used in previous Grand Challenges studies, we used a multi-step recruitment strategy to assemble a diverse panel of individuals from a range of disciplines relevant to global eye health from all regions globally to participate in a three-round, online, Delphi-like, prioritisation process to nominate and rank challenges in global eye health. Through this process, we developed both global and regional priority lists. Findings Between Sept 1 and Dec 12, 2019, 470 individuals complete round 1 of the process, of whom 336 completed all three rounds (round 2 between Feb 26 and March 18, 2020, and round 3 between April 2 and April 25, 2020) 156 (46%) of 336 were women, 180 (54%) were men. The proportion of participants who worked in each region ranged from 104 (31%) in sub-Saharan Africa to 21 (6%) in central Europe, eastern Europe, and in central Asia. Of 85 unique challenges identified after round 1, 16 challenges were prioritised at the global level; six focused on detection and treatment of conditions (cataract, refractive error, glaucoma, diabetic retinopathy, services for children and screening for early detection), two focused on addressing shortages in human resource capacity, five on other health service and policy factors (including strengthening policies, integration, health information systems, and budget allocation), and three on improving access to care and promoting equity. Interpretation This list of Grand Challenges serves as a starting point for immediate action by funders to guide investment in research and innovation in eye health. It challenges researchers, clinicians, and policy makers to build collaborations to address specific challenge

    Studies on Exploration of the Proximate Composition, Physical Attributes and Qualitative Phytochemical Analysis of Fresh Coriander Leafy Vegetables

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    The present investigation was undertaken in the Department of Processing and Food Engineering, College of Agricultural Engineering, Raichur to study the different properties of fresh coriander leafy vegetable like proximate composition, physical properties and bio-chemical properties. It was found that the moisture content, carbohydrate, crude protein, crude fat, crude fiber and ash content of fresh coriander leafy vegetable were found to 85.65, 4.26, 3.08, 0.3, 2.09 and 4.62 %, respectively. The total flavonoids, total phenols, chlorophyll content, ascorbic acid and ß-carotene content of fresh coriander leafy vegetable were found to be 318.40, 76.69, 222.36, 160.36, 34.32 mg/100 g, respectively. Overall, the combination of proximate composition, physical characteristics, and bio-chemical properties underscores the nutritional value and potential health benefits of fresh coriander leafy vegetables. Incorporating coriander into diets can provide essential nutrients and bioactive compounds, enhancing both the flavor and the potential well-being of individuals

    Modelling and Optimisation of Chitosan Anchored Titanium Dioxide Nano-Adsorbent for Dairy Industry Effluent Treatment

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    The present study emphasised the efficiency of chitosan anchored titanium dioxide nano-adsorbent on dairy industry effluent treatment. Chitosan titanium dioxide nano-adsorbent was synthesised by using chemical precipitation method and characterised for its particle size, surface morphology and texture. A four-factor-three-level Box–Behnken design along with response surface methodology was used to optimise the adsorption process parameters. Linear, two factor interaction, quadratic and cubic model techniques were used to demonstrate the influence of each parameter and their interaction effects on the responses. The quadratic models derived from the experimental data were used to predict the maximum per cent reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD). The optimised treatment combination for maximum per cent reduction in BOD (90.48%) and COD (82.10%) was found to be initial concentration of 100 mg L-1, pH of 7, dosage of 1.25 mg L-1 and contact time of 100 min
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