Anticonvulsant effect of celecoxib on pentylenetetrazole-induced convulsion: Modulation by NO pathway

This study aimed to examine whether celecoxib influences clonic seizure thresholds through modulation of nitric oxidergic (NO) pathway. The effect of celecoxib (1-5 mg per kg, p.o.) was investigated on clonic seizures induced by pentylenetetrazole (PTZ, 50 and 80 mg per kg, i.p.) in male Swiss mice. The interaction of celecoxib-induced effects with NO pathway was examined using a NO synthase (NOS) inhibitor, N(G)-omega-nitro-L-arginine methyl ester (L-NAME, 20 and 50 mg per kg, i.p.) and a NOS substrate, L-arginine (100 and 200 mg per kg, i.p.). The criteria for the development of seizure activity were the possibility for appearance of generalized clonus and prolongation of latency to the onset of convulsions following administration of 50 and 80 mg per kg of PTZ, respectively. Pretreatment with celecoxib (2.5 and 5 mg per kg) or L-NAME (50 mg per kg) induced anticonvulsant effect on the PTZ-induced clonic seizures. L-arginine at the dose of 200 mg per kg had proconvulsant effect. A sub-effective dose of celecoxib (1 mg per kg) induced an additive anticonvulsant effect when co-administered with L-NAME (20 mg per kg). Although L-arginine (100 mg per kg) per se did not influence PTZ-induced convulsion, it could attenuate the anticonvulsant effect of celecoxib (5 mg per kg). Our results indicate that celecoxib induces an anticonvulsant effect on clonic seizure threshold that may involve NO pathway.     

The fetal and neonatal brain protein neuronatin protects PC12 cells against certain types of toxic insult

The protein neuronatin is expressed in the nervous system of the fetus and neonate at a much higher level than in the adult. Its function is unknown. As a result of variable splicing, neuronatin mRNA exists in two forms, alpha and beta. Wild type PC12 cells express neuronatin-alpha. We have isolated a PC12 variant, called 1.9, that retains many of the neuron-like properties of wild type PC12 cells, but it does not express neuronatin and it exhibits markedly increased sensitivity to the toxic effects of nigericin, rotenone and valinomycin. Pretreatment of the 1.9 cells with alpha-methyltyrosine, which inhibits dopamine synthesis, had little effect on the cells' sensitivity to nigericin, rotenone or valinomycin indicating that dopamine-induced oxidative stress was not involved in the toxicity of these compounds. However, flattened cell subvariants of the 1.9 cells, which do not have any neuron-specific characteristics, did not exhibit increased sensitivity to nigericin indicating that some neuronal characteristic of the 1.9 cells contributed to the toxicity of nigericin. After the neuronatin-beta gene was transfected into and expressed in the 1.9 cells, they regained wild type PC12 levels of resistance to nigericin, rotenone and valinomycin. These studies suggest that the function of neuronatin during development could be to protect developing cells from toxic insult occurring during that period.     

Engineered antibody Fc variants with enhanced effector function

Antibody-dependent cell-mediated cytotoxicity, a key effector function for the clinical efficacy of monoclonal antibodies, is mediated primarily through a set of closely related Fcgamma receptors with both activating and inhibitory activities. By using computational design algorithms and high-throughput screening, we have engineered a series of Fc variants with optimized Fcgamma receptor affinity and specificity. The designed variants display >2 orders of magnitude enhancement of in vitro effector function, enable efficacy against cells expressing low levels of target antigen, and result in increased cytotoxicity in an in vivo preclinical model. Our engineered Fc regions offer a means for improving the next generation of therapeutic antibodies and have the potential to broaden the diversity of antigens that can be targeted for antibody-based tumor therapy.     

Alterations in expression of endometrial endothelial nitric oxide synthase and alpha(v)beta(3) integrin in women with endometriosis

OBJECTIVE: To determine the expression of endometrial endothelial nitric oxide synthase (eNOS) protein and alpha(v)beta(3) integrin in patients with and without endometriosis. DESIGN: Case-control cohort study. SETTING: University-based tertiary care center. PATIENT(S): Endometrial biopsy samples were obtained from 9 fertile women with regular cycles and 30 infertile women with varying severity of endometriosis. Peritoneal fluid levels of nitric oxide were determined in 13 infertile women with a normal pelvis and 12 infertile women with endometriosis. MAIN OUTCOME MEASURE(S): Expression of eNOS and alpha(v)beta(3) integrin protein in the endometrium and peritoneal fluid levels of nitric oxide. RESULTS: In patients with endometriosis, expression of eNOS was significantly increased in the glandular and luminal epithelium, with no significant changes in the stroma. Peritoneal fluid levels of nitric oxide were unchanged, and expression of alpha(v)beta(3) integrin expression in glandular and luminal epithelium was significantly decreased compared with controls. A significant negative correlation was observed between luminal expression of eNOS and alpha(v)beta(3) integrin and between glandular expression of eNOS and luminal expression of alpha(v)beta(3) integrin. CONCLUSION(S): The nitric oxide pathway may play a role in the pathogenesis of endometriosis.