排序方式: 共有94条查询结果,搜索用时 408 毫秒
51.
Naila Rasheed Ausaf Ahmad Chandra Prakash Pandey Rajnish Kumar Chaturvedi Mohtashim Lohani Gautam Palit 《Neurochemical research》2010,35(1):22-32
We aimed to evaluate the response of dopaminergic system in acute stress (AS) and chronic unpredictable stress (CUS) by measuring
dopamine (DA) levels, its receptor densities in the frontal cortex, striatum, hippocampus, amygdala and orbito-frontal cortex
regions of rat brain, and investigated the corresponding behavioral locomotor changes. Involvement of D1 receptor was also examined during AS and CUS using A 68930, a D1 selective agonist. Rats were exposed to AS (single immobilization for 150 min) and CUS (two different stressors for 7 days).
AS significantly decreased the DA levels in the striatum and hippocampus, and A 68930 pretreatment significantly reverted
these changes. However, in the frontal cortex significantly increased DA levels were remain unchanged following A 68930. CUS
led to a decrease of DA levels in the frontal cortex, striatum and hippocampus, which were normalized by A 68930. Saturation
radioligand binding assays revealed a significant decrease in the number of D1-like receptors in the frontal cortex during CUS, which were further decreased by A 68930 pretreatment. However, in the striatum
and hippocampus, A 68930 pretreatment reduced the CUS induced increase in the number of D1-like receptors. No significant changes were observed in the amygdala and orbito-frontal cortex during AS and CUS, while D2-like receptors were unchanged in all the brain regions studied. Locomotor activity was significantly decreased in both the
stress models, A 68930 pretreatment significantly increased stereotypic counts and horizontal activity. Thus, present investigation
provide insights into the differential regional response of dopaminergic system during AS and CUS. Further, neurochemical
and behavioral effects of D1 agonist pretreatment suggest specific modulatory role of D1 receptor under such stressful episodes. 相似文献
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Ahmet Yunus Ozdemir Inna Rom Jane Kovalevich William Yen Radhika Adiga Rajnish S. Dave Dianne Langford 《PloS one》2013,8(3)
Particularly interesting new cysteine- histidine- rich protein (PINCH) is an adaptor protein that our data have shown is required for neurite extension under stressful conditions. Our previous studies also report that PINCH is recalled by neurons showing decreased levels of synaptodendritic signaling proteins such as MAP2 or synaptophysin in the brains of human immunodeficiency virus (HIV) patients. The current study addressed potential role(s) for PINCH in neurodegenerative diseases. Mass spectrometry predicted the interaction of PINCH with Tau and with members of the heat shock response. Our in vitro data confirmed that PINCH binds to hyperphosphorylated (hp) Tau and to E3 ubiquitin ligase, carboxy-terminus of heat shock-70 interacting protein. Silencing PINCH prior to induction of hp-Tau resulted in more efficient clearance of accumulating hp-Tau, suggesting that PINCH may play a role in stabilizing hp-Tau. Accumulation of hp-Tau is implicated in more than 20 neuropathological diseases including Alzheimer''s disease (AD), frontotemporal dementia (FTD), and human immunodeficiency virus encephalitis (HIVE). Analyses of brain tissues from HIVE, AD and FTD patients showed that PINCH is increased and binds to hp-Tau. These studies address a new mechanism by which AD and HIV may intersect and identify PINCH as a contributing factor to the accumulation of hyperphosphorylated Tau. 相似文献
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Sheik Asraf Sheik Abdul Kader Mahalakshmi Ayyasamy Rajnish K. Narayanan Sridhar Jayavel Gunasekaran Paramasamy 《Biologia》2013,68(6):1054-1067
Zymomonas mobilis, a Gram-negative ethanologenic non-pathogenic bacterium, is reported to exhibit resistance to high concentrations of β-lactam antibiotics. In the present study, Z. mobilis was found to be resistant to I-IV generations of cephalosporins and carbapenems, i.e. narrow, broad and extended spectrum β-lactam antibiotics. We have analysed the genome of Z. mobilis (GenBank accession No.: NC 006526) harbouring multiple genes coding for β-lactamases (BLA), β-lactamase domain containing proteins (BDP) and penicillin binding proteins (PBP). The conserved domain database analysis of BDPs predicted them to be members of metallo β-lactamase superfamily. Further, class C specific multidomain AmpC (β-lactamase C) was found in the three β-lactamases. The β-lactam resistance determinants motifs, HXHXD, KXG, SXXK, SXN, and YXN are present in the BLAs, BDPs and PBPs of Z. mobilis. The predicted theoretical pI and aliphatic index values suggested their stability. One of the PBPs, PBP2, was predicted to share functional association with rod shape determining proteins (GenBank accession Nos. YP_162095 and YP_162091). Homology modelling of three dimensional structures of the β-lactam resistance determinants and further docking studies with penicillin and other β-lactam antibiotics indicated their substrate-specificity. Semi-quantitative PCR analysis indicated that the expression of all BLAs and one BDP are induced by penicillin. Disk diffusion assay, SDS-PAGE and zymogram analysis confirms the substrate specificity of the β-lactam resistance determinants. This study gives a broader picture of the β-lactam resistance determinants of a non-pathogenic ethanologenic Z. mobilis bacterium that could have implications in laboratories since it is routinely used in many research laboratories in the world for ethanol, fructooligosaccharides, levan production and has also been reported to be present in wine and beer as a spoilage organism. 相似文献
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Shubha Shukla Rajnish Kumar Chaturvedi Kavita Seth Neeta Singh Roy§ Ashok Kumar Agrawal 《Journal of neurochemistry》2009,109(2):436-451
Transplantation of neural stem cell (NSC)-derived dopamine (DA) neurons is associated with low survival of cells, which could be due to limited striatal innervations and uneven distribution of graft because of its dense neuronal core, limited host–graft interaction, poor axonal outgrowth, lack of continuous neurotrophic factors supply, and an absence of cell adhesion molecules mediated appropriate developmental cues. Olfactory ensheathing cells (OEC) express a variety of growth factors and cell adhesion molecules and promote axonal regrowth and functional recovery in spinal cord injury in animal models and patients. In the present study, we explored the possibility to increase the survival, function, axonal outgrowth and striatal reinnervation of NSC by co-grafting with OEC in 6-OHDA lesioned parkinsonian rats. In the presence of OEC, significantly enhanced survival of NSC-derived DA neurons and axonal fiber outgrowth was evident in the striatum of NSC+OEC co-grafted rats at 24 weeks post-grafting as compared with NSC alone grafted rats. The increased survival of NSC and their striatal reinnervation was further manifested in the form of significant and substantial restitution of motor function and neurochemical recovery in the co-grafted group. Significant enhanced expression of p75NTR (from OEC) and tyrosine hydroxylase (TH) (from NSC) confirmed the co-localization and survival of both types of cells at the transplantation site in co-grafted rats. Co-grafting results co-related well with our in vitro studies, which suggest that OEC not only significantly increase survival, neurite outgrowth and DA release of NSC-derived DA neuron but also protect against 6-OHDA neurotoxicity in co-culture conditions. These results collectively suggest that OEC increase the survival and function of transplanted NSC in 6-OHDA lesioned parkinsonian rats. 相似文献
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Neuronal processes exhibit exquisitely complex branching patterns crucial for the formation of distinct neural circuits. In this issue of Cell, Chen et al. (2006) show that the isoform diversity of the Dscam protein in Drosophila is required to establish stereotypical axonal branching patterns, suggesting that nonrandom expression of Dscam alternative splice variants determines neural connectivity. 相似文献
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Bajsa J McCluskey A Gordon CP Stewart SG Hill TA Sahu R Duke SO Tekwani BL 《Bioorganic & medicinal chemistry letters》2010,20(22):6688-6695
The antiplasmodial activities of sixty norcantharidin analogs were tested in vitro against a chloroquine sensitive (D6, Sierra Leone) and chloroquine resistant (W2) strains of Plasmodium falciparum. Forty analogs returned IC(50) values <500 μM against at least one of the P. falciparum strains examined. The ring open compound 24 ((1S,4R)-3-(allylcarbamoyl)-7-oxabicyclo[2.2.1]heptane-2-carboxylic acid) is the most active aliphatic analog (D6 IC(50)=3.0±0.0 and W2 IC(50)=3.0±0.8 μM) with a 20-fold enhancement relative to norcantharidin. Surprisingly, seven norcantharimides also displayed good antiplasmodial activity with the most potent, 5 returning D6=8.9±0.9 and W2 IC(50)=12.5±2.2 μM, representing a fivefold enhancement over norcantharidin. 相似文献
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Praloy Chakraborty Samanjoy Mukerjee Rajnish Sardana 《Indian pacing and electrophysiology journal》2010,10(4):184-189
Acute myocardial ischemia can cause ventricular tachycardia (VT) in patients with structurally normal heart. Contrary to the fact that in patients with chronic myocardial scarring the ventricular tachycardia is monomorphic, in patients with acute ischemia the ventricular tachycardia is polymorphic and is reversible with coronary revascularization.We are reporting a 40 year old male who presented with recurrent syncope due to polymorphic ventricular tachycardia in the context of normal QT interval in baseline ECG and normal left ventricular function without any evidence of myocardial injury. Due to recurrent fatal ventricular arrhythmia despite medical management, urgent coronary angiography was done which showed critical obstruction of right coronary artery (RCA). Considering the critical obstruction of RCA responsible for polymorphic VT, emergency PCI of RCA was done. After successful PTCA and stenting to RCA, he had another episode of polymorphic VT which was terminated with intravenous phenytoin. Seven days after the PCI, 24 hours Holter monitoring was done which showed normal sinus rhythm with infrequent ventricular premature complexes and no evidence of VT. He was asymptomatic at six months follow-up. 相似文献