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71.
Ngampramuan S Baumert M Beig MI Kotchabhakdi N Nalivaiko E 《American journal of physiology. Regulatory, integrative and comparative physiology》2008,294(1):R132-R141
To better understand the central mechanisms that mediate increases in heart rate (HR) during psychological stress, we examined the effects of systemic and intramedullary (raphe region) administration of the serotonin-1A (5-HT(1A)) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetraline (8-OH-DPAT) on cardiac changes elicited by restraint in hooded Wistar rats with preimplanted ECG telemetric transmitters. 8-OH-DPAT reduced basal HR from 356 +/- 12 to 284 +/- 12 beats/min, predominantly via a nonadrenergic, noncholinergic mechanism. Restraint stress caused tachycardia (an initial transient increase from 318 +/- 3 to 492 +/- 21 beats/min with a sustained component of 379 +/- 12 beats/min). beta-Adrenoreceptor blockade with atenolol suppressed the sustained component, whereas muscarinic blockade with methylscopolamine (50 microg/kg) abolished the initial transient increase, indicating that sympathetic activation and vagal withdrawal were responsible for the tachycardia. Systemic administration of 8-OH-DPAT (10, 30, and 100 microg/kg) attenuated stress-induced tachycardia in a dose-dependent manner, and this effect was suppressed by the 5-HT(1A) antagonist WAY-100635 (100 microg/kg). Given alone, the antagonist had no effect. Systemically injected 8-OH-DPAT (100 microg/kg) attenuated the sympathetically mediated sustained component (from +85 +/- 19 to +32 +/- 9 beats/min) and the vagally mediated transient (from +62 +/- 5 to +25 +/- 3 beats/min). Activation of 5-HT(1A) receptors in the medullary raphe by microinjection of 8-OH-DPAT mimicked the antitachycardic effect of the systemically administered drug but did not affect basal HR. We conclude that tachycardia induced by restraint stress is due to a sustained increase in cardiac sympathetic activity associated with a transient vagal withdrawal. Activation of central 5-HT(1A) receptors attenuates this tachycardia by suppressing autonomic effects. At least some of the relevant receptors are located in the medullary raphe-parapyramidal area. 相似文献
72.
73.
Jonathan P Coe Irfan Rahman Nathalie Sphyris Alan R Clarke David J Harrison 《Free radical biology & medicine》2002,32(2):187-196
We have investigated the roles of the antioxidant glutathione and p53 in the response of embryonic stem (ES) cells to oxidative stress. ES cells express gammaGCS, a critical enzyme in glutathione (GSH) biosynthesis. Treatment with the pro-oxidant menadione led to elevation of GSH, a strong apoptotic response and reduced clonogenic survival. Addition of BSO, a specific gammaGCS inhibitor depleted GSH pools and prevented the menadione-induced increase in GSH, sensitizing cells to oxidative insult. Although p53 status had no bearing on either the basal levels of GSH or the menadione-induced GSH response, the levels of menadione-induced apoptosis were reduced in the absence of p53. We conclude that the pathways involving p53 and GSH act independently to protect against the deleterious effects of oxidative damage. Furthermore, the presence of an intact p53 pathway confers a long-term growth advantage post oxidative stress. Thus, in the absence of p53 ES cells bearing genotoxic damage are less likely to be propagated, suggesting that p53-dependent apoptosis acts to limit the deleterious effects of oxidative stress during early development. 相似文献
74.
Salinity tolerance in some mangrove species from Pakistan 总被引:1,自引:0,他引:1
Growth, ionic and water relations of three mangrove species viz. Avicennia marina, Ceriops tagal and Rhizophora mucronata werestudied in different seawater concentrations (0, 25, 50, 75 and 100%).All mangrove species showed optimal growth at 50% seawater. Relativelymore biomass was accumulated by R. mucronata while C. tagalhad the tallest individuals. Tissue water potential became more negativewith the increase in salinity and stomatal conductance was decreased in allplants. Higher stomatal conductance was noted in R. mucronata,followed by A. marina and C. tagal. Sodium and chloride ionsincreased with the increase in salinity and this accumulation was muchhigher in A. marina. 相似文献
75.
Mushtaq Hussain Syeda Qamarunnissa Saboohi Raza Javed Qureshi Abdul Wajid Sheikh A. Rasool 《Biologia》2009,64(5):852-858
DNA photolyase is perhaps the most ancient and direct arsenal in curing the UV-induced dimers formed in the microbial genome.
Out of two cofactors of the enzyme, catalytic and light harvesting, differences in the latter have provided basis for categorizing
photolyases of prokaryotes as folate and deazaflavin types. In the present study, the homology modeling of DNA photolyase
of Enterococcus faecalis was undertaken. The predicted models were structurally compared with the crystal structure coordinates of photolyases from
Escherichia coli (folate type) and Anacystis nidulans (deazaflavin type). Discrepancies present in the multiple sequence alignment and tertiary structures, particularly at the
light harvesting cofactor (methenyltetrahydrofolic acid, MTHF; 8-hydroxy-5-deazaflavin, 8-HDF) binding sites indicated the
mechanistic nature of enterococcal photolyase. Concisely, despite the greater holistic homology with folate-type photolyase,
enterococcal photolyase was characterized as deazaflavin-type. The presence of 8-HDF binding sites and groove architecture
of substrate binding sites were also found supportive in this regard. The inter cofactor distance and/or orientation also
implied to the efficient energy transfer in photolyase of Enterococcus in comparison with E. coli. In addition, we observed relatively high protein deformability in the enterococcal genome, which may favors the repair action
of photolyase. The findings are expected to provide molecular insights into the difference in sunlight inactivation rate of
two important fecal contamination indicators, namely Enterococcus and E. coli. 相似文献
76.
Muhammad Hidayat Rasool 《Indian journal of microbiology》2008,48(3):401-404
The present study was conducted to develop and evaluate an experimental ISCOM-based infectious bursal disease (IBD) vaccine.
The indigenous very virulent infectious bursal disease virus (vvIBDV) already attenuated and adapted to Vero cell line was
used. After denaturation of viral proteins with sodium dodecyl sulphate (SDS), an IBD-ISCOM was constructed. The non-incorporated
viral components were separated from ISCOM by centrifugation of dialysate. The pathogenicity and immunogenicity trials were
conducted in 3-week-old broiler chicken. A commercial oil-emulsified vaccine (CEVAC IBD K) was used for comparison. There
were no clinical signs of disease, gross or microscopic lesions in bursa of Fabricius in group G1 vaccinated with ISCOM-based
vaccine and bursa to body weight ratio were comparable to un-vaccinated control group (G3). The virus-neutralizing antibody
titers were significantly (P<0.05) higher in group G1 as compared with group G2 which was vaccinated with commercial vaccine.
On challenge with vvIBDV, 100%, 75% and 0.00% protection was achieved in G1, G2 and G3, respectively. The results indicated
that ISCOM-based IBD vaccine is safe and immunogenic. 相似文献
77.
78.
Gousia Mehraj Anzar A. Khuroo Salman Qureshi Insha Muzafar Cynthia Ross Friedman Irfan Rashid 《Biodiversity and Conservation》2018,27(5):1055-1072
In an age of Anthropocene, the urban landscapes are recognised as the ‘hotspots’ of human-mediated alien species introductions. As the cities provide an ideal natural experimental system to investigate the patterns of alien plant diversity in urban landscapes, the present study aimed to unravel the taxonomic, biogeographic and ecological patterns of alien flora of Srinagar—one of the largest urban centres in the Himalayan biodiversity hotspot. The alien flora of Srinagar comprises 325 species, constituting ca.35% of total flora of the city. Out of the 325 alien species documented, 157 species (43%) were recorded to be under cultivation, while 168 species (57%) were growing in the wild (i.e., outside cultivation); those growing in the wild, in turn, comprised 110 cultivation escapes and 58 accidentally introduced plant species. Biogeographically, two-third of the alien plant diversity reported from Srinagar is native to Asia-Temperate. This indicates that climatic similarity between Asia-Temperate and Kashmir Himalayas facilitate in flourishing similar floristic diversity. The study highlights a relatively higher proportion of herbaceous growth form in the aliens growing in the wild (80%) than those under cultivation (43%). Similarly, 82% of the alien species under cultivation had a perennial life span, but those growing in the wild were dominated by annuals (44%). Currently, 45 species are growing as casuals and 124 species are naturalised (including 105 naturalised non-invasive and 19 naturalised invasive). Along the continuum of casual-naturalised-invasive categories, the contribution of cultivation escapes and accidently introduced aliens contrastingly shows decreasing and increasing trends respectively. Interestingly, the results revealed that the human practice of stopping cultivation of alien escapes increased rapidly as we move along the continuum. Thus, the present study has investigated the patterns of alien plant diversity in the urban landscape of Srinagar, and the results obtained offer scientific insights toward better scientific understanding and management of plant invasions in this Himalayan city, with wider policy implications for neighbouring urbanised landscapes in the Himalayas and other mountainous regions across the world. 相似文献
79.
Irfan Jawed Margarita Velarde Roland Därr Katherine I. Wolf Karen Adams Aradhana M. Venkatesan Sanjeeve Balasubramaniam Marianne S. Poruchynsky James C. Reynolds Karel Pacak Tito Fojo 《Cellular and molecular neurobiology》2018,38(5):1099-1106
Patients harboring germline mutations in the succinate dehydrogenase complex subunit B (SDHB) gene present with pheochromocytomas and paragangliomas (PPGL) that are more likely malignant and clinically aggressive. The combination chemotherapy cyclophosphamide, vincristine, and dacarbazine (CVD) was retrospectively evaluated in patients with SDHB-associated metastatic PPGL.Query Twelve metastatic PPGL patients harboring SDHB mutations/polymorphisms with undetectable SDHB immunostaining were treated with CVD. CVD therapy consisted of 750 mg/m2 cyclophosphamide with 1.4 mg/m2 vincristine on day 1 and 600 mg/m2 dacarbazine on days 1 and 2, every 21–28 days. Treatment outcome was determined by RECIST criteria as well as determination of response duration and progression-free and overall survivals. A median of 20.5 cycles (range 4–41) was administered. All patients had tumor reduction (12–100% by RECIST). Complete response was seen in two patients, while partial response was observed in 8. The median number of cycles to response was 5.5. Median duration of response was 478 days, with progression-free and overall survivals of 930 and 1190 days, respectively. Serial [18F]-fluorodeoxyglucose positron emission tomography and computed tomography imaging demonstrated continued incremental reduction in maximal standardized uptake values (SUVmax) values in 26/30 lesions. During treatment administration, the median SUV decreased from?> 25 to?< 6, indicating the efficacy of chemotherapy over a prolonged period of time. Prolonged therapy results in continued incremental tumor reduction, and is consistent with persistent drug sensitivity. CVD chemotherapy is recommended to be considered part of the initial management in patients with metastatic SDHB-related PPGL. 相似文献
80.
Atahar Husein Azfar Jamal Mohammad Zulfazal Ahmed Mohammad Arish Rahat Ali Shams Tabrez Fayyaz Rasool Abdur Rub 《Journal of cellular biochemistry》2018,119(9):7844-7854
Leishmania is a protozoan parasite that resides and replicates in macrophages and causes leishmaniasis. The parasite alters the signaling cascade in host macrophages and evades the host machinery. Small G‐proteins are GTPases, grouped in 5 different families that play a crucial role in the regulation of cell proliferation, cell survival, apoptosis, intracellular trafficking, and transport. In particular, the Ras family of small G‐proteins has been identified to play a significant role in the cellular functions mentioned before. Here, we studied the differential expression of the most important small G‐proteins during Leishmania infection. We found major changes in the expression of different isoforms of Ras, mainly in N‐Ras. We observed that Leishmania donovani infection led to enhanced N‐Ras expression, whereas it inhibited K‐Ras and H‐Ras expression. Furthermore, an active N‐Ras pull‐down assay showed enhanced N‐Ras activity. L donovani infection also increased extracellular signal–regulated kinase 1/2 phosphorylation and simultaneously decreased p38 phosphorylation. In contrast, pharmacological inhibition of Ras led to reduction in the phosphorylation of extracellular signal–regulated kinase 1/2 and enhanced the phosphorylation of p38 in Leishmania‐infected cells, which could lead to increased interleukin‐12 expression and decreased interleukin‐10 expression. Indeed, farnesylthiosalicyclic acid (a Ras inhibitor), when used at the effective level in L donovani–infected macrophages, reduced amastigotes in the host macrophages. Thus, upregulated N‐Ras expression during L donovani infection could be a novel immune evasion strategy of Leishmania and would be a potential target for antileishmanial immunotherapy. 相似文献