284 research outputs found

    Assessment of Vegetative Phenology with Respect to Leaf Elongation Pattern of Avicennia Marina and Rhizophora Mucronata in Hajambro Creek, Indus Delta, Pakistan

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    Leaves emergence and the rate of elongation have been studied in Hajambro creek in Indus deltaic region, Pakistan. Leaves emergence was found higher during the summer months (mostly pre-monsoon period), that was March April, May and June. Leaves of A. marina that were observed from March to July, till the leaves reached their maximum length (about 77 mm), showed a gradual increase in their length, reaching maximum in April. Leaves of Avicennia marina reached their maximum length (about 77 mm) in about 113 days. The leaves showed gradual increase in their length, reaching maximum in April (0.97mm d-1). The per-day increment in length was 0.54 mm d-1. As reaching their maximum length (77mm), the per-day increment in the length gradually slower down. The leaves of Rhizophora mucronata were observed from February to November. The leaves of Rhizophora mucronata showed elongation rate of 0.24 mm d-1 from the day of the first observation till the leaves reached their maximum length (120 mm). The maximum time required by the leaves to reach their maximum length (120 mm) was 236 days. The rates of elongation of leaves are also fast in summer. The rate of elongation of the leaves was found to be highly correlated with the temperature (

    Distribution and Zonation Patterns of Cerithideopsilla cingulata (Gmelin 1791) (Gastropoda: Potamididae) in Mangrove Stands at Sandspit Backwater, Karachi, Pakistan

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    Abstract.-Mangroves create distinctive ecological environments that are characterized by a significant biodiversity which provides food and shelter to a variety of organisms. Gastropods are the largest and most diverse class of mollusc. To assess the seasonal variation in distribution and abundance of Cerithideopsilla cingulata sampling was conducted during July, October 2002 and January, April 2003, respectively in mangrove stands, at Sandspit backwater. A total of 14 core samples were collected from rhizosphere (7 cores) and non-rhizosphere (7 cores). Four cores from each site were used for biomass analysis and the remaining three cores were used for sediment analysis. The top 10 cm of each core was sliced at 1 cm interval and each layer was sieved through 1 mm 2 mesh. Live C cingulata were sorted, counted and weighed (wet). For sediment analysis, cores were treated in the same manner for the determination of water content, organic and inorganic matter. We observed a seasonal variation in total number of C cingulata and the density also varied between two sites. The non-rhizosphere is found to be most productive in terms of number of C. cingulata. During the period between January to April C. cingulata are more abundant. Their number ranges from 185-214 individuals/m 2 in non rhizosphere and 115-119 individuals/m 2 in rhizosphere, respectively. Pearson correlation showed that the C. cingulata numbers were positively correlated to the concentration of inorganic matter in the sediment and were negatively correlated in terms of deregulated distribution of sedimentary organic matter. Our data will help understand the ecological niches preferred by C. cingulata in mangrove sites

    Evaluation of immune response to hepatitis B vaccine in health care workers at a tertiary care hospital in Pakistan: an observational prospective study

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    Background: Seroconversion rates reported after Hepatitis B virus (HBV) vaccination globally ranges from 85–90%. Health care workers (HCWs) are at high risk of acquiring HBV and non responders\u27 rates after HBV vaccination were not reported previously in Pakistani HCWs. Therefore we evaluated immune response to HBV vaccine in HCWs at a tertiary care hospital in Karachi, Pakistan.Methods: Descriptive observational study conducted at Aga Khan University from April 2003 to July 2004. Newly HBV vaccinated HCWs were evaluated for immune response by measuring serum Hepatitis B surface antibody (HBsAb) levels, 6 weeks post vaccination. Results: Initially 666 employees were included in the study. 14 participants were excluded due to incomplete records. 271 (41%) participants were females and 381(59%) were males. Majority of the participants were young (50 years of age. Male non responders were more frequent (18%) than female (8%). Conclusion: Seroconversion rate after HBV vaccination in Pakistani HCWs was similar to that reported in western and neighboring population. HCWs with reduced immune response to HBV vaccine in a high disease prevalent population are at great risk. Therefore, it is crucial to check post vaccination HBsAb in all HCWs. This strategy will ensure safety at work by reducing nosocomial transmission and will have a cost effective impact at an individual as well as at national level, which is very much desired in a resource limited country

    Lipidomic analysis of variation in response to simvastatin in the Cholesterol and Pharmacogenetics Study

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    Statins are commonly used for reducing cardiovascular disease risk but therapeutic benefit and reductions in levels of low-density lipoprotein cholesterol (LDL-C) vary among individuals. Other effects, including reductions in C-reactive protein (CRP), also contribute to treatment response. Metabolomics provides powerful tools to map pathways implicated in variation in response to statin treatment. This could lead to mechanistic hypotheses that provide insight into the underlying basis for individual variation in drug response. Using a targeted lipidomics platform, we defined lipid changes in blood samples from the upper and lower tails of the LDL-C response distribution in the Cholesterol and Pharmacogenetics study. Metabolic changes in responders are more comprehensive than those seen in non-responders. Baseline cholesterol ester and phospholipid metabolites correlated with LDL-C response to treatment. CRP response to therapy correlated with baseline plasmalogens, lipids involved in inflammation. There was no overlap of lipids whose changes correlated with LDL-C or CRP responses to simvastatin suggesting that distinct metabolic pathways govern statin effects on these two biomarkers. Metabolic signatures could provide insights about variability in response and mechanisms of action of statins

    A coherent polarimeter array for the Large Scale Polarization Explorer balloon experiment

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    We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a 0.6\sim 0.6 meter telescope providing an angular resolution of 1.5\sim1.5 degrees. The LSPE experiment aims at large scale, high sensitivity measurements of CMB polarization, with multi-frequency deep measurements to optimize component separation. The STRIP Q-band channel is crucial to accurately measure and remove the synchrotron polarized component, while the W-band channel, together with a bolometric channel at the same frequency, provides a crucial cross-check for systematic effects.Comment: In press on the Proceedings of the SPIE Conference Astronomical Telescopes + instrumentation 2012, Amsterdam, paper 8446-27

    Lipid Classes and Fatty Acid Patterns are Altered in the Brain of γ-Synuclein Null Mutant Mice

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    The well-documented link between α-synuclein and the pathology of common human neurodegenerative diseases has increased attention to the synuclein protein family. The involvement of α-synuclein in lipid metabolism in both normal and diseased nervous system has been shown by many research groups. However, the possible involvement of γ-synuclein, a closely-related member of the synuclein family, in these processes has hardly been addressed. In this study, the effect of γ-synuclein deficiency on the lipid composition and fatty acid patterns of individual lipids from two brain regions has been studied using a mouse model. The level of phosphatidylserine (PtdSer) was increased in the midbrain whereas no changes in the relative proportions of membrane polar lipids were observed in the cortex of γ-synuclein-deficient compared to wild-type (WT) mice. In addition, higher levels of docosahexaenoic acid were found in PtdSer and phosphatidylethanolamine (PtdEtn) from the cerebral cortex of γ-synuclein null mutant mice. These findings show that γ-synuclein deficiency leads to alterations in the lipid profile in brain tissues and suggest that this protein, like α-synuclein, might affect neuronal function via modulation of lipid metabolism

    Roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in an insect

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    <p>Abstract</p> <p>Background</p> <p>In insect classical conditioning, octopamine (the invertebrate counterpart of noradrenaline) or dopamine has been suggested to mediate reinforcing properties of appetitive or aversive unconditioned stimulus, respectively. However, the roles of octopaminergic and dopaminergic neurons in memory recall have remained unclear.</p> <p>Results</p> <p>We studied the roles of octopaminergic and dopaminergic neurons in appetitive and aversive memory recall in olfactory and visual conditioning in crickets. We found that pharmacological blockade of octopamine and dopamine receptors impaired aversive memory recall and appetitive memory recall, respectively, thereby suggesting that activation of octopaminergic and dopaminergic neurons and the resulting release of octopamine and dopamine are needed for appetitive and aversive memory recall, respectively. On the basis of this finding, we propose a new model in which it is assumed that two types of synaptic connections are formed by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus to neurons inducing conditioned response and the other being connections from neurons representing conditioned stimulus to octopaminergic or dopaminergic neurons representing appetitive or aversive unconditioned stimulus, respectively. The former is called 'stimulus-response connection' and the latter is called 'stimulus-stimulus connection' by theorists studying classical conditioning in higher vertebrates. Our model predicts that pharmacological blockade of octopamine or dopamine receptors during the first stage of second-order conditioning does not impair second-order conditioning, because it impairs the formation of the stimulus-response connection but not the stimulus-stimulus connection. The results of our study with a cross-modal second-order conditioning were in full accordance with this prediction.</p> <p>Conclusion</p> <p>We suggest that insect classical conditioning involves the formation of two kinds of memory traces, which match to stimulus-stimulus connection and stimulus-response connection. This is the first study to suggest that classical conditioning in insects involves, as does classical conditioning in higher vertebrates, the formation of stimulus-stimulus connection and its activation for memory recall, which are often called cognitive processes.</p

    Cinnamomum cassia Bark in Two Herbal Formulas Increases Life Span in Caenorhabditis elegans via Insulin Signaling and Stress Response Pathways

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    Background: Proving the efficacy and corresponding mode of action of herbal supplements is a difficult challenge for evidence-based herbal therapy. A major hurdle is the complexity of herbal preparations, many of which combine multiple herbs, particularly when the combination is assumed to be vitally important to the effectiveness of the herbal therapy. This issue may be addressed through the use of contemporary methodology and validated animal models. Methods and Principal Findings: In this study, two commonly used traditional herbal formulas, Shi Quan Da Bu Tang (SQDB) and Huo Luo Xiao Ling Dan (HLXL) were evaluated using a survival assay and oxidative stress biomarkers in a well-established C. elegans model of aging. HLXL is an eleven herb formula modified from a top-selling traditional herbal formula for the treatment of arthritic joint pain. SQDB consists of ten herbs often used for fatigue and energy, particularly in the aged. We demonstrate here that SQDB significantly extend life span in a C. elegans model of aging. Among all individual herbs tested, two herbs Cinnamomum cassia bark (Chinese pharmaceutical name: Cinnamomi Cortex, CIN) and Panax ginseng root (Chinese pharmaceutical name: Ginseng Radix, GS) significantly extended life span in C. elegans. CIN in both SQDB and HLXL formula extended life span via modulation of multiple longevity assurance genes, including genes involved in insulin signaling and stress response pathways. All the life-span-extending herbs (SQDB, CIN and GS) also attenuated levels of H2O2 and enhanced small heat shock protein expression. Furthermore, the life spanextending herbs significantly delayed human amyloid beta (Aβ)-induced toxicity in transgenic C. elegans expressing human Aβ. Conclusion/Significance:These results validate an invertebrate model for rapid, systematic evaluation of commonly used Chinese herbal formulations and may provide insight for designing future evidence-based herbal therapy(s). Copyright: © 2010 Yu et al.published_or_final_versio
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