387 research outputs found

    Evaluation of allelopathic effect of Eclipta alba (L.) Hassk on biochemical activity of Amaranthus spinosus L., Cassia tora L. and Cassia sophera L.

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    A study was conducted to assess the magnitude of suppressing ability of Eclipta alba (L.) Hassk. on some selected weeds of Aligarh namely, Amaranthus spinosus L., Cassia tora L. and Cassia sophera L. The research finding was conducted to evaluate the effect of aqueous leaf leachate and organic fractions of donor plant on biochemical activities (carbohydrate content, chlorophyll content and protein content). The result shows that aqueous leachate and organic fractions reduced the level of biochemical activities. Carbohydrate content was increased in treated plants as compared to control while chlorophyll content and protein content were reduced as compared to the control. Aqueous leachate showed maximum toxicity on weeds than organic fractions. The reduction may be due to the allelochemicals present in E. alba leaves.Key words: Allelochemicals, aqueous leachate, organic fractions, chlorophyll content, carbohydrate content, Eclipta alba

    Assessment of allelopathic potential of Cassia sophera L. on seedling growth and physiological basis of weed plants

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    Allelopathy is described as both beneficial and deleterious biochemical interaction between plant and weeds, and/or plant and microorganisms through the production of chemical compounds that escape into the environment and subsequently influence the growth and development of neighbouring plants. The present laboratory experimental study was conducted to evaluate the allelopathic effect of Cassia sophera (L.) on three weed plants (Chenopodium album L., Melilotus alba Medik and Nicotiana plumbaginifolia Viv.). Aqueous extracts of Cassia at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination, seedling growth, dry biomass, leaf area, relative water content, chlorophyll and protein content of test plants under laboratory conditions. The aqueous extracts had a significant retardatory effect on seed germination of test plants which varied among species and also with the different concentrations used. Root length and shoot length of weed species decreased significantly when plants were exposed to increasing aqueous concentration (0.5, 1, 2 and 4%). The noticed reduction in dry biomass, leaf area and relative water content were also significant. Physiological parameters (total chlorophyll content and protein content) in relation to three test species (M. alba, C. album and N. plumbaginifolia) were significantly reduced with the different concentrations of aqueous extract used. From this we can predict that cassia might possess allelochemicals that causes the suppressive ability.Keywords: Allelopathy, aqueous extract, Melilotus alba, Chenopodium alba and Nicotiana plumbaginifoliaAfrican Journal of Biotechnology, Vol. 13(9), pp. 1037-1046, 26 February, 201

    Ecological study of an important medicinal plant of Kashmir valley, Capsella bursa pastoris

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    The vegetation of a geographical landscape relies heavily on the local environment. Altitude is a major factor in shaping the phytodiversity and biomass. The biomass study is essential for estimating the productivity of natural ecosystems. The demand for medicinal plants has been increased and it has become a trend to utilize forests and its products according to their productivities. The present study was aimed to investigate the attitudinal and other ecological variations in biomass of an important medicinal plant of Kashmir, Capsella bursa pastoris. The method, we used to estimate the biomass of selected medicinal plant at different ecological sites, was the harvest method. We compared the biomass (fresh and dry matter) of two protected siteshaving altitudinal and other ecological variations. The maximum biomass was recorded at the site I with lower altitude and the minimum value was recorded at site II with higher altitude. The minimum above ground biomass was recorded at site II. However, at Bijbehara, biomass variation was observed at two different sites. Maximum biomass was found at the site II (Dara Shikoh garden Bijbehara). The below-ground biomass showed a considerable increase on decreasing altitude. Roots react instantly to better soil moisture conditions. The maximum biomass in underground parts at the site I may be because of translocation of the main materials from the above-ground parts to the below-ground parts as the above-ground biomass was greater at same altitude. The minimum biomass at higher altitude and the ecologically disturbed site may be because of unfavourable microclimatic conditions and degradation of medicinal plants by grazing activity respectively.Â

    Hepatitis C virus cell-cell transmission and resistance to direct-acting antiviral agents

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    Hepatitis C virus (HCV) is transmitted between hepatocytes via classical cell entry but also uses direct cell-cell transfer to infect neighboring hepatocytes. Viral cell-cell transmission has been shown to play an important role in viral persistence allowing evasion from neutralizing antibodies. In contrast, the role of HCV cell-cell transmission for antiviral resistance is unknown. Aiming to address this question we investigated the phenotype of HCV strains exhibiting resistance to direct-acting antivirals (DAAs) in state-of-the-art model systems for cell-cell transmission and spread. Using HCV genotype 2 as a model virus, we show that cell-cell transmission is the main route of viral spread of DAA-resistant HCV. Cell-cell transmission of DAA-resistant viruses results in viral persistence and thus hampers viral eradication. We also show that blocking cell-cell transmission using host-targeting entry inhibitors (HTEIs) was highly effective in inhibiting viral dissemination of resistant genotype 2 viruses. Combining HTEIs with DAAs prevented antiviral resistance and led to rapid elimination of the virus in cell culture model. In conclusion, our work provides evidence that cell-cell transmission plays an important role in dissemination and maintenance of resistant variants in cell culture models. Blocking virus cell-cell transmission prevents emergence of drug resistance in persistent viral infection including resistance to HCV DAAs

    Anatomical considerations and emerging strategies for reducing new onset conduction disturbances in percutaneous structural heart disease interventions

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    Transcatheter procedures offer an alternative to cardiac surgery in select patients with structural heart disease (SHD). Unfortunately, inadvertent disruption of electrical pathways and subsequent development of new onset conduction disturbances can occur in up to 5–70% of percutaneous interventions, result in pacemaker implantation, and confer a worse prognosis. The physical proximity between the conduction system (atrioventricular node, bundle of His, and bundle branches) and the site of percutaneous repair is increasingly recognized as a key factor influencing new onset conduction disturbance development in procedures located near the conduction system. This review covers the incidence, clinical significance, and mechanisms of new onset conduction disturbances and discusses current and emerging strategies to address this complication in these populations

    The Impact of Pandemic Influenza H1N1 on Health-Related Quality of Life: A Prospective Population-Based Study

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    BACKGROUND: While the H1N1v influenza pandemic in 2009 was clinically mild, with a low case-fatality rate, the overall disease burden measured in quality-adjusted life years (QALY) lost has not been estimated. Such a measure would allow comparison with other diseases and assessment of the cost-effectiveness of pandemic control measures. METHODS AND FINDINGS: Cases of H1N1v confirmed by polymerase chain reaction (PCR) and PCR negative cases with similar influenza-like illness (ILI controls) in 7 regions of England were sent two questionnaires, one within a week of symptom onset and one two weeks later, requesting information on duration of illness, work loss and antiviral use together with EQ-5D questionnaires. Results were compared with those for seasonal influenza from a systematic literature review. A total QALY loss for the 2009 pandemic in England was calculated based on the estimated total clinical cases and reported deaths. A total of 655 questionnaires were sent and 296 (45%) returned. Symptoms and average illness duration were similar between confirmed cases and ILI controls (8.8 days and 8.7 days respectively). Days off work were greater for cases than ILI controls (7.3 and 4.9 days respectively, p  =  0.003). The quality-adjusted life days lost was 2.92 for confirmed cases and 2.74 for ILI controls, with a reduction in QALY loss after prompt use of antivirals in confirmed cases. The overall QALY loss in the pandemic was estimated at 28,126 QALYs (22,267 discounted) of which 40% was due to deaths (24% with discounting). CONCLUSION: Given the global public health significance of influenza, it is remarkable that no previous prospective study of the QALY loss of influenza using standardised and well validated methods has been performed. Although the QALY loss was minor for individual patients, the estimated total burden of influenza over the pandemic was substantial when compared to other infectious diseases

    A Database of Domain Definitions for Proteins with Complex Interdomain Geometry

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    Protein structural domains are necessary for understanding evolution and protein folding, and may vary widely from functional and sequence based domains. Although, various structural domain databases exist, defining domains for some proteins is non-trivial, and definitions of their domain boundaries are not available. Here, we present a novel database of manually defined structural domains for a representative set of proteins from the SCOP “multi-domain proteins” class. (http://prodata.swmed.edu/multidom/). We consider our domains as mobile evolutionary units, which may rearrange during protein evolution. Additionally, they may be visualized as structurally compact and possibly independently folding units. We also found that representing domains as evolutionary and folding units do not always lead to a unique domain definition. However, unlike existing databases, we retain and refine these “alternate” domain definitions after careful inspection of structural similarity, functional sites and automated domain definition methods. We provide domain definitions, including actual residue boundaries, for proteins that well known databases like SCOP and CATH do not attempt to split. Our alternate domain definitions are suitable for sequence and structure searches by automated methods. Additionally, the database can be used for training and testing domain delineation algorithms. Since our domains represent structurally compact evolutionary units, the database may be useful for studying domain properties and evolution

    Influenza Outbreak during Sydney World Youth Day 2008: The Utility of Laboratory Testing and Case Definitions on Mass Gathering Outbreak Containment

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    BACKGROUND:Influenza causes annual epidemics and often results in extensive outbreaks in closed communities. To minimize transmission, a range of interventions have been suggested. For these to be effective, an accurate and timely diagnosis of influenza is required. This is confirmed by a positive laboratory test result in an individual whose symptoms are consistent with a predefined clinical case definition. However, the utility of these clinical case definitions and laboratory testing in mass gathering outbreaks remains unknown. METHODS AND RESULTS:An influenza outbreak was identified during World Youth Day 2008 in Sydney. From the data collected on pilgrims presenting to a single clinic, a Markov model was developed and validated against the actual epidemic curve. Simulations were performed to examine the utility of different clinical case definitions and laboratory testing strategies for containment of influenza outbreaks. Clinical case definitions were found to have the greatest impact on averting further cases with no added benefit when combined with any laboratory test. Although nucleic acid testing (NAT) demonstrated higher utility than indirect immunofluorescence antigen or on-site point-of-care testing, this effect was lost when laboratory NAT turnaround times was included. The main benefit of laboratory confirmation was limited to identification of true influenza cases amenable to interventions such as antiviral therapy. CONCLUSIONS:Continuous re-evaluation of case definitions and laboratory testing strategies are essential for effective management of influenza outbreaks during mass gatherings

    Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

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    Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

    Phase II trial of Modified Vaccinia Ankara (MVA) virus expressing 5T4 and high dose Interleukin-2 (IL-2) in patients with metastatic renal cell carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Interleukin-2 (IL-2) induces durable objective responses in a small cohort of patients with metastatic renal cell carcinoma (RCC) but the antigen(s) responsible for tumor rejection are not known. 5T4 is a non-secreted membrane glycoprotein expressed on clear cell and papillary RCCs. A modified vaccinia virus Ankara (MVA) encoding 5T4 was tested in combination with high-dose IL-2 to determine the safety, objective response rate and effect on humoral and cell-mediated immunity.</p> <p>Methods</p> <p>25 patients with metastatic RCC who qualified for IL-2 were eligible and received three immunizations every three weeks followed by IL-2 (600,000 IU/kg) after the second and third vaccinations. Blood was collected for analysis of humoral, effector and regulatory T cell responses.</p> <p>Results</p> <p>There were no serious vaccine-related adverse events. While no objective responses were observed, three patients (12%) were rendered disease-free after nephrectomy or resection of residual metastatic disease. Twelve patients (48%) had stable disease which was associated with improved median overall survival compared to patients with progressive disease (not reached vs. 28 months, p = 0.0261). All patients developed 5T4-specific antibody responses and 13 patients had an increase in 5T4-specific T cell responses. Although the baseline frequency of Tregs was elevated in all patients, those with stable disease showed a trend toward increased effector CD8+ T cells and a decrease in Tregs.</p> <p>Conclusion</p> <p><b>V</b>accination with MVA-5T4 did not improve objective response rates of IL-2 therapy but did result in stable disease associated with an increase in the ratio of 5T4-specific effector to regulatory T cells in selected patients.</p> <p>Trial registration number</p> <p>ISRCTN83977250</p
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