82 research outputs found
Nerve injury induces a rapid efflux of nitric oxide (NO) detected with a novel NO microsensor
No full textAn early step in repair of the leech CNS is the appearance of endothelial nitric oxide synthase (eNOS) immunoreactivity and NOS activity, but coincident generation of NO at the lesion after injury has not been shown. This is important because NO can regulate microglial cell motility and axon growth. Indirect measurement of NO with the standard citrulline assay demonstrated that NO was generated within 30 min after nerve cord injury. A polarographic NO-selective self-referencing microelectrode that measures NO flux noninvasively was developed to obtain higher spatial and temporal resolution. With this probe, it was possible to demonstrate that immediately after the leech CNS was injured, NO left the lesion with a mean peak efflux of 803 +/- 99 fmol NO cm(-2) sec(-1). NO efflux exponentially declined to a constant value, as described through the equation f(t) = y(o) + ae(-t/tau), with tau = 117 +/- 30 sec. The constant y(o) = 15.8 +/- 4.5 fmol cm(-2) represents a sustained efflux of NO. Approximately 200 pmol NO cm(-2) is produced at the lesion (n = 8). Thus, injury activates eNOS already present in the CNS and precedes the accumulation of microglia at the lesion, consistent with the hypothesis that NO acts to stop the migrating microglia at the lesion site
Injury-induced nitric oxide signaling in the leech central nervous system
No full textAxons of the leech Hirudo medicinalis regenerate following injury by crush or transection. We have used this system to study the early cellular and molecular events that occur following injury, in order to understand the remarkable regenerative capacity of the leech CNS. We demonstrate that injury to the leech CNS results in endothelial nitric oxide Synthase (eNOS)-like immunoreactivity in the glial and microglial cells at the injured site and that this injury-induced eNOS activity guides microglial migration and leads to accumulation. In particular, application of the nitric oxide (NO) donor, SPNO, significantly reduces the velocity of migrating microglia and prevents their accumulation. Application of a NOS inhibitor does not affect the speed of the migrating microglia, and allows the microglia to migrate through the lesion, thus preventing accumulation at the injury site. These data suggest that in the absence of NO, the microglia continue to migrate, but fail to accumulate at the injury site. We have directly measured the NO produced by the eNOS-like protein at the injury site with a novel NO-selective microelectrode. These experiments indicate that following injury, there is a rapid efflux of NO followed by a slow lingering component. Injury-induced NO appears to activate soluble guanylate cyclase (sGC) present in the leech CNS. Injury to the leech CNS induces specific NO-dependent cGMP-like immunoreactivity at the lesion site that occurs in a time-dependent manner following injury. Inhibition of sGC activity with [1H-[1,2,4] oxadizole [4,3-a] quinoxalin-1-one] (ODQ) blocks this cGMP-like immunoreactivity at the lesion site. Injury-induced NO-dependent cGMP-like immuunoreactivity shares a similar distribution with accumulated microglia at the lesion site. We suggest that the injury-induced NO exerts its effect on the migrating microglia through cGMP and hypothesize that the injury-induced NO-dependent cGMP serves as a directional cue for the migrating microglia
Author Correction: Nano-fibre Integrated Microcapsules: A Nano-in-Micro Platform for 3D Cell Culture
No full textAuthor Correction to: "Nano-fibre Integrated Microcapsules: A Nano-in-Micro Platform for 3D Cell Culture
Performance of Gujarat economy: an analysis of growth and instability
No full textSince the State’s inception, the growth process in Gujarat and its regions has experienced ups and downs in the economic activities. Not much attention is attributed to short term fluctuations in the growth of economic activities as long as the long term growth depicts an upward trend. However, if the short term fluctuations become frequent and adversely affect the long term rate of growth, there is a need for a closer look. Tackling instability acquires importance for improving the lot of small and marginal farmers, who are more affected by spells of bad years. Instability in agricultural production raises risk in farm production, affecting farmers’ incomes and decisions for investments to adopt new technologies. This paper is devoted to looking at the long term macro-economic growth pattern of Gujarat since its inception. It highlights the problem of instability in economic growth – both for the economy and in particular for agricultural sector. The comparative picture of Gujarat in the national economy is presented, together with a discussion on changing structure of Gujarat’s economy from early 1960s to 2008-09. The analysis of instability is also carried out at the sectoral level. Analysis of instability is attempted in terms of structure of the economy. Income is the variable selected for analysis as it is a comprehensive measure of economic activity. For agriculture, the paper opts ‘output’ for the sectoral analysis.Agricultural growth, Instability, Sectoral growth, Gujarat
Corporate Governance, Competition and Firm Performance: Evidence from India.
No full textThe aim of this paper is to show the interaction effect of product market competition and corporate governance variables on firm performance. While the linkage between internal governance mechanism and firm performance is well established in several studies, the interaction between internal and external governance mechanism has received scanty attention in emerging market economies. Here we have shown the independent and interaction effect of ownership and competition variable on firm productivity. Contrary to conventional wisdom, we document that competition has in reality become a discernible force in developing economies. The econometric modelling result shows while the standalone effect of ownership variable on productivity is mostly insignificant, there is a strong positive interaction effect with competition variables.
Synthesis and Antimicrobial Activity of Some New Substituted Aryloxy-4-Thiazolidinones
No full textNine new substituted aryloxy-4-thiazolidones have been prepared from corresponding schiff bases and thioglycolic acid in benzene using Stark and Dien apparatus. The synthesized compounds were identified by spectral studies and screened for antimicrobial activity
Schistosoma mansoni P-glycoprotein levels increase in response to praziquantel exposure and correlate with reduced praziquantel susceptibility
No full textAuthor Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Molecular and Biochemical Parasitology 167 (2009): 54-59, doi:10.1016/j.molbiopara.2009.04.007.One potential physiological target for new antischistosomals is the parasite's system for excretion of wastes and xenobiotics. P-glycoprotein (Pgp), a member of the ATP-binding cassette superfamily of proteins, is an ATP-dependent efflux pump involved in transport of toxins and xenobiotics from cells. In vertebrates, increased expression of Pgp is associated with multidrug resistance in tumor cells. Pgp may also play a role in drug resistance in helminths. In this report, we examine the relationship between praziquantel (PZQ), the current drug of choice against schistosomiasis, and Pgp expression in Schistosoma mansoni. We show that levels of RNA for SMDR2, a Pgp homolog from S. mansoni, increase transiently in adult male worms following exposure to sublethal concentrations (100 - 500 nM) of PZQ. A corresponding, though delayed, increase in anti-Pgp immunoreactive protein expression occurs in adult males following exposure to PZQ. The level of anti-Pgp immunoreactivity in particular regions of adult worms also increases in response to PZQ. Adult worms from an Egyptian S. mansoni isolate with reduced sensitivity to PZQ express increased levels of SMDR2 RNA and anti-Pgp-immunoreactive protein, perhaps indicating a role for multidrug resistance proteins in development or maintenance of PZQ resistance.SMM, RSK, WM, and RMG were supported by NIH grants R01 AI40522 and R01 AI 73660. RMG was also supported by the Neal Cornell Research Fund at the Marine Biological Laboratory. RMG and SMM were also supported in part by NIH/NSF Woods Hole Center for Oceans and Human Health grant WHOI-A100354/A100360. Support was also received from the NIH Biocurrents Research Center at MBL (P41 RR001395)
Synthesis of Novel 1,3-Diacetoxy-Acridones as Cytotoxic Agents and their DNA-Binding Studies
No full textA series of novel substituted acridones (1–15) have been synthesized. Their in vitro cytotoxicity against human breast adenocarcinoma (MCF-7) and human promyelocytic leukemia (HL-60) cell lines has been investigated. The compounds 11, 12, 14 and 15 showed moderate activity against MCF-7 cell lines with IC50 value < 5.83 μM. The compounds 8, 10–12, and 15 showed moderate activity against HL-60 cell lines with IC50 value < 1.75 μM. The DNAbinding properties of the compounds were evaluated based on their affinity or intercalation with CT-DNA measured with absorption titration. The compound 12 bearing planar diacetoxy tricyclic ring linked with butyl piperidine side chain showed highest binding affinity with binding constant (Ki) 10.38 ×10 ×M–1. The examination of the relationship between lipophilicity and cytotoxic properties of acridones showed a poor correlation
(D. Don) Soó in Nepalese Himalaya
No full textHarvesting of orchids for medicine and salep production is a traditional practice, and increasing market demand is spurring illegal harvest. Ethno-ecological studies in combination with the effect of anthropogenic disturbance are lacking for orchids. We compared population density and structure, and tuber biomass of Dactylorhiza hatagirea (D. Don) Soó for three years in two sites: Manang, where harvesting of medicinal plants was locally regulated (protected), and Darchula, where harvesting was locally unregulated (unprotected). Six populations were studied along an elevation gradient by establishing 144 temporary plots (3 × 3 m2) from 3,400 to 4,600 m elevations. Mean density of D. hatagirea was significantly higher in the locally protected (1.31 ± 0.17 plants/m2) than in the unprotected (0.72 ± 0.06 plants/m2) site. The protected site showed stable population density with high reproductive fitness and tuber biomass over the three-year period. A significant negative effect (p <.1) of relative radiation index (RRI) on the density of the adult vegetative stage and a positive effect of herb cover on juvenile and adult vegetative stages were found using mixed zero-inflated Poisson (mixed ZIP) models. The densities of different life stages were highly sensitive to harvesting and livestock grazing. Significant interactions between site and harvesting and grazing indicated particularly strong negative effects of these disturbances on densities of juvenile and adult reproductive stages in the unprotected site. Semi-structured interviews were conducted with informants (n = 186) in the villages and at the ecological survey sites. Our interview results showed that at the protected site people are aware of the conservation status and maintain sustainable populations, whereas the opposite was the case at the unprotected site where the populations are threatened. Sustainability of D. hatagirea populations, therefore, largely depends on controlling illegal and premature harvesting and unregulated livestock grazing, thus indicating the need for permanent monitoring of the species.</p
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