9 research outputs found
ISOLATION AND MOLECULAR IDENTIFICATION OF POTENTIALLY PATHOGENIC Escherichia coli AND Campylobacter jejuni IN FERAL PIGEONS FROM AN URBAN AREA IN THE CITY OF LIMA, PERU
Convulsive properties of D,L homocysteine and D,L homocysteine thiolactone in adult rats
Introduction: Hyperhomocysteinemia is related to epileptogenesis and suboptimal control of seizures in the patients with epilepsy. Available data suggest that homocysteine can be harmful to human cells because of its metabolic conversion to homocysteine thiolactone, a reactive thioester. The aim of the study was to investigate the convulsive properties of equimolar concentrations of D,L homocysteine and D,L homocysteine thiolactone in adult rats. Methods: Adult male Wistar rats were divided into following groups: 1. saline-treated (C, n=10), 2. D, L homocysteine 8 mM/kg, i.p. (H; n=8), and 3. D,L homocysteine-thiolactone (Ht; n=8). Seizure behavior was assessed by the incidence, latency, number and intensity of seizure episodes. Seizure severity was described by a descriptive scale with grades 0-4.Results: There were no behavioural signs of seizure activity in C group. The incidence of convulsions was lower in group H comparing to the Ht group but statistical significance was not attained. Latency to the first seizure onset was significantly higher in H comparing to the Ht group (p<0.01). Median number of seizure episodes and severity of seizure episodes per rat were significantly lower in H comparing to Ht group.Conclusion: Our findings suggest that D,L homocysteine thiolactone exerts stronger convulsive effect comparing to the equimolar concentration of D,L homocysteine
The Peptide Ligase Activity of Human Legumain Depends on Fold Stabilization and Balanced Substrate Affinities
Protein modification by enzymatic breaking and forming of peptide bonds significantly expands the repertoire of genetically encoded protein sequences. The dual protease-ligase legumain exerts the two opposing activities within a single protein scaffold. Primarily localized to the endolysosomal system, legumain represents a key enzyme in the generation of antigenic peptides for subsequent presentation on the MHCII complex. Here we show that human legumain catalyzes the ligation and cyclization of linear peptides at near-neutral pH conditions, where legumain is intrinsically unstable. Conformational stabilization significantly enhanced legumain’s ligase activity, which further benefited from engineering the prime substrate recognition sites for improved affinity. Additionally, we provide evidence that specific legumain activation states allow for differential regulation of its activities. Together these results set the basis for engineering legumain proteases and ligases with applications in biotechnology and drug development
Exercise Decreases Susceptibility to Homocysteine Seizures: the Role of Oxidative Stress
The aim of the study was to examine the effects of chronic exercise training on seizures induced by homocysteine thiolactone (HCT) in adult rats. Rats were assigned to: sedentary control; exercise control; sedentary +HCT; exercise + HCT group. Animals in the exercise groups ran 30 min daily on a treadmill for 30 consecutive days (belt speed 20 m/min), while sedentary rats spent the same time on the treadmill (speed 0 m/min). On the 31st day, the HCT groups received HCT (8.0 mmol/kg), while the control groups received vehicle. Afterwards, convulsive behavior and EEG activity were registered. Lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activity were ascertained in the rat hippocampus. No signs of seizures were registered in sedentary and exercise control rats. Seizure latency was increased, while number of seizure episodes and spike-and-wave discharges (SWD) in EEG were decreased in the exercise + HCT compared to the sedentary +HCT group. Seizure incidence, the severity thereof and duration of SWDs were not significantly different between these groups. Exercise partly prevented increase of lipid peroxidation and decrease of the SOD and CAT activity after HCT administration. These results indicate beneficial effects of exercise in model of HCT induced seizures in rats, what could be, at least in part, a consequence of improved antioxidant enzymes activity
The effect of subchronic supplementation with folic acid and L-arginine on homocysteine-induced seizures
The aim of the present study was to examine the effect of subchronic co-administration of folic acid (F) and L-arginine (A) on behavioural and electroencephalographic (EEG) characteristics of DL homocysteine thiolactone (H) induced seizures in adult rats. The activity of membrane ATPases in different brain regions were also investigated. Rats were treated with F, A, or vehicle for 15 days (regimen: F 5 mg/kg + A 500 mg/kg (F5A500); F 10 mg/kg + A 300 mg/kg (F10A300)). Seizures were elicited by convulsive dose of H (H, F5A500H, F10A300H) Subchronic supplementation with F and A did not affect seizure incidence, number of seizure episodes, and severity in F5A500H and F10A300H groups vs. H group. However, a tendency to increase latency and decrease the number of seizure episodes was noticed in the F10A300H group. EEG mean spectral power densities during ictal periods were significantly lower in F10A300H vs. H group. The activity of Na+/K+-ATPase and Mg2+-ATPase was significantly increased in almost all examined structures in rats treated with F and A. We can conclude that subchronic supplementation with folic acid and L-arginine has an antiepileptic effect in DL homocysteine thiolactone induced epilepsy.2nd European-Section Meeting of the International-Academy-of-Cardiovascular-Sciences (IACS), Oct 08-10, 2015, Belgrade, Serbi
17β-Estradiol-Induced Synaptic Rearrangements Are Accompanied by Altered Ectonucleotidase Activities in Male Rat Hippocampal Synaptosomes
The effect of intracerebroventricular administration of orexin receptor type 2 antagonist on pentylenetetrazol-induced kindled seizures and anxiety in rats
Stress neuropeptide levels in adults with chest pain due to coronary artery disease: potential implications for clinical assessment
: Substance P (SP) and neuropeptide Y (NPY) are neuropeptides
involved in nociception. The study of biochemical markers of pain in
communicating critically ill coronary patients may provide insight for pain
assessment and management in critical care. Purpose of the study was to
to explore potential associations between plasma neuropeptide levels and
reported pain intensity in coronary critical care adults, in order to test the
reliability of SP measurements for objective pain assessment in critical
care