Demonstration of intermediates between deoxy and carbonmonoxy hemoglobins by anaerobic high-performance liquid chromatography

The effect of glucagon and insulin on rat liver phosphorylase phosphatase activity in vivo was investigated. The activity of phosphatase was found to decrease following the administration of glucagon and increase with insulin in a reversible manner. No change was detected in the activity of heat-stable phosphatase inhibitors in the hormone-treated samples. Liver protein kinases (regulatory subunit of cAMP-dependent protein kinase and/or Ca2+-dependent phosphorylase kinase) are suggested to regulate the activity of hepatic phosphorylase phosphatase (type 1 and 2A).     

Stability of asymmetrical hybrid hemoglobins. Determination by anaerobic high performance liquid chromatography

Asymmetrical hybrid hemoglobins formed in mixtures of Hb A and Hb S, Hb F and Hb S, Hb S and Hb York(beta 146 His----Pro), and Hb A and Hb York were separated by high performance liquid chromatography on cation and anion exchange columns under anaerobic conditions. The ratio of the hybrid hemoglobin to the total mixture was consistently lower than that theoretically expected and decreased with longer elution times. The hybrid tetramer appears to be unstable even under anaerobic conditions and dissociates into alpha beta dimers. The time course of dissociation of the hybrid hemoglobins was determined by varying the separation programs and thus separating the hybrid hemoglobin at different elution times. The rate of the dissociation of the hybrid hemoglobins studied follows first order kinetics. The lines representing the time course of dissociation of hybrid hemoglobins were extrapolated to time 0 to determine the fraction of the hybrid hemoglobin in the mixture prior to separation. The values obtained for equimolar mixtures of Hb A and Hb S and Hb York and Hb S or Hb A were in agreement with the expected theoretical value (50%). In contrast, the value obtained for hybrid hemoglobin FS was slightly less (about 40%). AY and SY hybrid hemoglobins dissociated into dimers at a considerably faster rate than did AS and FS hybrid hemoglobins, possibly because of the mutation at the beta 146-position in hybrid hemoglobins containing alpha beta Y dimers. This mutation hinders the formation of salt bridges that normally stabilize the "T" quaternary conformation. Since such hybrid hemoglobins have a partial "R" conformation even when deoxygenated, their rate of dissociation to dimers is expected to increase.     

Acceleration of antibacterial activity of curcumin loaded biopolymers against methicillin‐resistant Staphylococcus aureus: Synthesis,optimization, and evaluation

Curcumin is a polyphenolic molecule with antibacterial, antioxidant, anti‐inflammatory, and antimicrobial properties. This study aimed to prepare nanocurcumin by encapsulating in biopolymers to improve its stability, bioavailability, water‐solubility, antibacterial efficiency against methicillin‐resistant Staphylococcus aureus. Three effective variables of curcumin concentration, polymer concentration, and water volume on curcumin‐loaded polymer nanoparticles, were optimized. The average size of polyacrylic acid (PAA), polyvinyl alcohol (PVA), and polyethyleneimine (PEI) nanoparticles were obtained 75.2, 77.1, 86.4 nm, respectively. The nanoparticles had a spherical shape, a smooth and uniform surface morphology. The MIC of PAA, PVA, and PEI nanoparticles was 0.480, 0.390, and 0.340 mg/mL, respectively and the MIC of PAA, PVA, and PEI combined with methicillin was 0.330, 0.260, and 0.200 mg/mL, respectively. According to the results, curcumin‐loaded PEI nanoparticles had the highest inhibitory effect against methicillin‐resistant S. aureus among the synthesized nanoparticles. The results showed that solvent volume, polymer concentration and curcumin concentration had a significant effect on particle size. The inhibitory properties of curcumin nanoparticles significantly increased due to the smaller particle size and increased penetration into the bacterium. Curcumin‐loaded nanoparticles can be promising drug carriers for the treatment of infections, cancer, and other diseases.     

Dose-Dependent Effects of Astaxanthin on Ischemia/Reperfusion Induced Brain Injury in MCAO Model Rat

Excitotoxicity and oxidative stress are central to the pathology of the nervous system, and inhibition of excitotoxicity induced by glutamate is one of the therapeutic goals determined for stroke. The present study aimed to investigate the effects of Astaxanthin, a potent natural antioxidant, on complications caused by acute cerebral stroke. In this research, 60 male Wistar rats were used which were divided into 5 groups as follow: (1) the sham group (vehicle), (2) the ischemic control group (vehicle), and the ischemic groups treated by Astaxanthin with doses of 25, 45, and 65 mg/kg. In the ischemic groups, ischemic model was performed by middle cerebral artery occlusion (MCAO) method, and the Astaxanthin administration was carried out after the artery occlusion and before opening the artery. The obtained results indicated that Astaxanthin could significantly reduce stroke volume, neurological deficits, and lipid peroxidation. Moreover, it was able to restore total oxidant status (TOS) and caspase 3 level to the normal level. The activity of antioxidant enzyme glutathione peroxidase (GPX), and the expression of catalase, GPx and nuclear factor kappa B (NFκb) genes, which were reduced after ischemia, were increased. This phenomenon was particularly pronounced for glutamate transporter 1 (GLT-1). Furthermore, Astaxanthin decreased the augmented pro-apoptotic gene Bax and restored the reduced Bcl2 expression to the normal level. Significant effects on the P53 and PUMA expression were not observed. Overall, the medium dosage of Astaxanthin appears to be more effective in reducing the complications of ischemia, particularly on our major study endpoints (stroke volume and neurological defects). Longer studies with a more frequent administration of Astaxanthin are required to better understand the precise mechanism of Astaxanthin.

     

Quercetin postconditioning attenuates gastrocnemius muscle ischemia/reperfusion injury in rats

Quercetin, an antioxidant derived from plants, can play a beneficial role in the protection of various tissues against ischemia-reperfusion injuries (IRI). The purpose of the present research was to investigate the protective effects of quercetin on gastrocnemius muscle ischemia-reperfusion. A total of 80 adult male Wistar rats (weights: 250–300 g) were divided into ten groups (n = 8 per group). We used silk 6.0 surgical thread to create a knit to occlude the femoral artery and vein for 3 hr. The treated groups, which comprised half of each experimental group, received intraperitoneal injections of 150 mg/kg quercetin after the ischemia. Blood flow was subsequently reestablished in the reperfusion phase. The rats were kept in reperfusion for 3, 7, 14, or 28 days after which they were killed with high doses of anesthetic drugs, and the gastrocnemius muscles were removed and fixed. Tissue processing, hematoxylin and eosin and toluidine blue staining, and immunohistochemistry were used to assess tumor necrosis factor-α (TNF-α) and nuclear factor κB (NF-κB) levels. A comparison between treated and untreated ischemic sites showed that on the third day of reperfusion, the severity of edema and NF-κB level decreased significantly; on the 7th day of reperfusion, the severity of edema and the levels of TNF-α and NF-κB decreased significantly; and on the 14th day of reperfusion, all of the parameters showed significant decreases. On the 28th day of reperfusion, there were significantly decreased levels of TNF-α and NF-κB, and decreased mast cell infiltration when compared with the untreated groups. According to the results, administration of quercetin after ischemia could significantly prevent gastrocnemius muscle IRI.