Modulation of rat peripheral polymorphonuclear leukocyte response by nitric oxide and arginine

The effect of nitric oxide (NO) on the luminol-dependent chemiluminescence (LCL) response of rat polymorphonuclear leukocytes (PMNLs) was analyzed by using sodium nitroprusside (SNP), a NO donor, and L-arginine (L-arg), a NO precursor. A significant reduction in the LCL intensity was observed in presence of SNP (100 μmol/L) or L-arg (5 or 10 mmol/L) in arachidonic acid (AA) phorbol ester (PMA) and formyl- methionyl-leucyl-phenylalanine stimulated PMNLs. However, opsonized zymosan-induced LCL was not attenuated significantly. Reduction in hydroxyl radical and superoxide generation was also observed in SNP- or L-arg-pretreated cells. D-Arg (10 mmol/L) pretreatment did not inhibit PMNLs' LCL response. Furthermore, methylene blue (5 μmol/L) and L-NG- mono methyl-L-arginine (100 or 300 μmol/L) significantly attenuated the LCL response, as induced by various agonists. Cyclic GMP did not alter the reactive oxygen species generation from rat PMNLs. In addition, AA-induced release of myeloperoxidase, a marker of azurophilic granules, was found to be enhanced in L-arg- (10 mmol/L) pretreated PMNLs. The results suggest that NO inhibits free radical generation from rat PMNLs

Curcumin-Loaded Apotransferrin Nanoparticles Provide Efficient Cellular Uptake and Effectively Inhibit HIV-1 Replication In Vitro

Curcumin (diferuloylmethane) shows significant activity across a wide spectrum of conditions, but its usefulness is rather limited because of its low bioavailability. Use of nanoparticle formulations to enhance curcumin bioavailability is an emerging area of research.In the present study, curcumin-loaded apotransferrin nanoparticles (nano-curcumin) prepared by sol-oil chemistry and were characterized by electron and atomic force microscopy. Confocal studies and fluorimetric analysis revealed that these particles enter T cells through transferrin-mediated endocytosis. Nano-curcumin releases significant quantities of drug gradually over a fairly long period, ∼50% of curcumin still remaining at 6 h of time. In contrast, intracellular soluble curcumin (sol-curcumin) reaches a maximum at 2 h followed by its complete elimination by 4 h. While sol-curcumin (GI(50) = 15.6 µM) is twice more toxic than nano-curcumin (GI(50) = 32.5 µM), nano-curcumin (IC(50)<1.75 µM) shows a higher anti-HIV activity compared to sol-curcumin (IC(50) = 5.1 µM). Studies in vitro showed that nano-curcumin prominently inhibited the HIV-1 induced expression of Topo II α, IL-1β and COX-2, an effect not seen with sol-curcumin. Nano-curcumin did not affect the expression of Topoisomerase II β and TNF α. This point out that nano-curcumin affects the HIV-1 induced inflammatory responses through pathways downstream or independent of TNF α. Furthermore, nano-curcumin completely blocks the synthesis of viral cDNA in the gag region suggesting that the nano-curcumin mediated inhibition of HIV-1 replication is targeted to viral cDNA synthesis.Curcumin-loaded apotransferrin nanoparticles are highly efficacious inhibitors of HIV-1 replication in vitro and promise a high potential for clinical usefulness

Principles of sensorimotor learning.

The exploits of Martina Navratilova and Roger Federer represent the pinnacle of motor learning. However, when considering the range and complexity of the processes that are involved in motor learning, even the mere mortals among us exhibit abilities that are impressive. We exercise these abilities when taking up new activities - whether it is snowboarding or ballroom dancing - but also engage in substantial motor learning on a daily basis as we adapt to changes in our environment, manipulate new objects and refine existing skills. Here we review recent research in human motor learning with an emphasis on the computational mechanisms that are involved

Evidence for the presence of a plasma factor which acts synergistically to ADP-induced platelet aggregation

This article does not have an abstract

Effect of centbucridine &amp; lignocaine on biochemical changes in isoproterenol induced ischemia in rats

Effect of lignocaine and centbucridine against isoproterenol-induced biochemical changes was studied in the rat. Isoproterenol (40 mg/kg twice) increased the heart weight, level of manolaldehyde (MDA) and activity of acid phosphatase, but decreased the myocardial phospholipid content at 48 h. In addition, increase in plasma triglyceride, cholesterol, MDA and creatine phosphokinase activity was observed. Pretreatment of the animals with lignocaine (10 mg/kg) or centbucridine (1, 3 and 10 mg/kg) protected the animals against these biochemical changes. However, increase in heart weight consequent to isoproterenol treatment could not be prevented. Total protection against creatine phosphokinase release in the blood was also not observed. The results suggest that the two drugs inhibit lipolysis. They may also inhibit phospholipases leading to protection against ischemia-induced changes in the rat

Effect of pulmonary thromboembolism on circulating neutrophils in mice

The role of free radical generation and its scavenging enzymes in circulating mice polymorphonuclear leukocytes (PMNLs) has been studied following pulmonary thromboembolism. Levels of malonaldehyde (MDA), O<SUB>2</SUB> radical generation, activity of superoxide dismutase (SOD), catalase (CAT), lactate dehydrogenase (LDH), myeloperoxidase (MPO) and lysozyme were estimated in lysed neutrophil preparations. Activities of SOD and CAT were increased in neutrophils, while animals showed 60&#177; 4% thrombocytopenia. Levels of MDA in PMNLs were also elevated significantly following thrombosis. However, there was no significant change in superoxide radical generation, after thrombotic challenge, in mice neutrophils. The present study provides evidence for the involvement of free radicals in mice pulmonary thromboembolism

Pulmonary thromboembolism-induced alterations in nitric oxide release from rat circulating neutrophils

We have earlier reported that neutrophils play an important role in pulmonary thromboembolism. The effect of circulating polymorphonuclear leukocytes (PMNL) isolated from normal and thrombotic rats was, therefore, studied on platelet aggregation in platelet-rich plasma. PMNL inhibited the platelet aggregation in a concentration- and time-dependent manner at 37 ° C. The platelet aggregation inhibitory response of PMNL was more pronounced in the presence of superoxide dismutase and was abolished by hemoglobin and methylene blue. These observations suggested that the inhibitory effect of PMNL on platelets was mediated by neutrophil-derived relaxing factor. PMNL, obtained after thromboembolism, inhibited the platelet aggregation response more strongly due to an increased release of nitric oxide from them. It is suggested that PMNL play an important role in the regulation of hemostasis

Nitric oxide modulates blood-brain barrier permeability during infections with an inactivated bacterium

The objective of the present investigation was to study the involvement of NO in regulating the permeability of the blood-brain barrier (BBB) during infections, since NOS is known to be induced following infections. The administration of inactivated Escherichia coli (a source of lipopolysaccharide) or poly (I:C), an interferon inducer, to rats increased the permeability of BBB significantly. This increase was found to be potentiated in the presence of L-arginine, a substrate for NOS, while D-arginine had no such effect. N-nitro L-arginine methyl ester, an inhibitor of NOS, and dexamethasone, an inhibitor of NOS induction, blocked the E. coli-induced effects. These results suggest that during infections, NOS inductions causes the release of large quantities of NO, resulting in increased BBB permeability