Designing an ELISA Method for Measurement of Human IgG and IgM Antibodies against SARS-CoV-2

Background and purpose: Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, an indirect ELISA method was designed to measure the human IgM and IgG antibodies against SARS-CoV-2. Materials and methods: Protein sequence of nucleocapsid antigen from SARS-CoV-2 was expressed in E. coli BL21 and then was purified by chromatography. The purified protein was confirmed by SDS-PAGE and Western blotting. An indirect ELISA method was designed to measure the specific IgG and IgM antibodies against SARS-CoV-2 using recombinant N protein. The optimized ELISA method was then applied to measure the IgG and IgM antibodies in 61 infected or recovered COVID-19 patients and in 31 healthy controls. Finally, data obtained from the designed ELISA method were compared with those of a commercially approved ELISA kit. Results: The recombinant nucleocapsid protein was successfully expressed and purified which was confirmed by SDS-PAGE and Western blotting. The amount of optical densities obtained from the designed ELISA method was similar to those of the commercial kit in 61 patients and 31 controls. The sensitivity and specificity of the designed ELISA method for IgG were 100% compared with the commercial ELISA kit, while the sensitivity and specificity for IgM were 96.72 and 96.77, respectively. Conclusion: Serological tests alone are not suitable for diagnosis; however, their combination with molecular tests increases the accuracy and sensitivity of the COVID-19 diagnosis. These tests are also vauable for epidemiological studies

Comparison between the effects of quercetin on seizure threshold in acute and chronic seizure models

Flavonoids are important constituents of food and beverages, and several studies have shown that they have neuroactive properties. Many of these compounds are ligands for γ-aminobutyric acid type A receptors in the central nervous system. This study aimed to investigate the anticonvulsant effects of quercetin (3,3′,4′,5,7-pentahydroxyflavone), which is a flavonoid found in plants, in rats treated with pentylenetetrazole in acute and chronic seizure models. Single intraperitoneal administration of quercetin did not show anticonvulsive effects against acute seizure. Similarly, multiple oral pretreatment with quercetin did not have protective effects against acute seizure. However, multiple intraperitoneal administration of quercetin (25 and 50 mg/kg) significantly increased time to death compared with the control (p < 0.001). However, quercetin pretreatment had no significant effects on the pattern of convulsion development during all periods of kindling. But on the test day, quercetin (100 mg/kg) could significantly increase generalized tonic–clonic seizure onset (GTCS) and decrease GTCS duration compared with the control (p < 0.01, p < 0.05). We conclude that quercetin has a narrow therapeutic dose range for anticonvulsant activities in vivo, and it has different effects on the seizure threshold. The different effects of quercetin on seizure threshold may occur through several mechanisms

Rutin activates the MAPK pathway and BDNF gene expression onbeta-amyloid induced neurotoxicity in rats

Flavonoids are present in foods such as fruits and vegetables. A relationship between the consumption offlavonoid-rich foods and prevention of human disease including neurodegenerative disorders has beendemonstrated. We assessed the effect of rutin (3,3�,4�,5,7-pentahydroxyflavone-3-rhamnoglucoside) onthe mitogen-activated protein kinase (MAPK) pathway, memory retrieval and oxidative stress in ratsinjected with �-amyloid (A�), which is implicated to have an important role in Alzheimer’s disease (AD).A� was injected bilaterally in the deep frontal cortex of rat brain. Next, rutin and saline were injected(i.p.) for 3 weeks. In comparison to the control group, rutin significantly increased extracellular signal-regulated protein kinase 1 (ERK1), cAMP response element-binding protein (CREB) and brain-derivedneurotrophic factor (BDNF) gene expression in the hippocampus of rats. Rutin (100 mg/kg) significantlyincreased memory retrieval compared to the control group. Malondialdehyde (MDA) level in the hip-pocampus of the rutin group was significantly lower than those in the control group. The content ofsulfhydryl groups in the rutin group was higher than that in the control group. The findings show apossibility that rutin may have beneficial effects against neurotoxicity of A� on memory in rats