Promotion Effect of Palladium on BiVO4 Sensing Material for Epinephrine Detection

In this study, the Pd/BiVO4 composite was prepared by hydrothermal method as an electrochemical sensing material for epinephrine. X-ray diffraction, scanning electron microscopy, and a transmission electron microscope were used to characterize the samples. In the electrochemical detection system, cyclic voltammetry and differential pulse voltammetry were applied to measure the concentration of the epinephrine solution (0.9–27.5 µM) with the Pd/BiVO4-coated glassy carbon electrode. As a result, the oxidation peak current of Pd/BiVO4/GCE demonstrated good linearity with the epinephrine concentration. The detection limit of the epinephrine concentration by cyclic voltammetry and differential pulse voltammetry were 0.262 µM and 0.154 µM, respectively. Additionally, the proposed sensing material exhibited good reproducibility, stability, and selectivity. A plausible sensing mechanism was proposed.

Platelet aggregation in patients with chronic heart failure in a "vortex" flow

Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Исследование выполнено в рамках фундаментальной темы НИИ кардиологии АААА-А15-115123110026-3. Platelet aggregation mechanisms are studied using standard methods without taking turbulence into account. However, in cardiovascular diseases, the blood rheology changes, and the parameters of the turbulent flow acquire strong prothrombotic effects. The adhesion of several platelets creates a "snowball" effect with platelet hyperaggregation, leading to rapid vessel occlusion. Thus, the study of platelet aggregation in patients with cardiovascular diseases in conditions of creating a "vortex" flow in platelet-rich plasma is very relevant. Objective to study the effect of "vortex" flow in platelet-rich plasma on spontaneous and epinephrine-induced platelet aggregation in patients with CHF. Material and method. We studied 15 patients (75% of them men) with CHD, having CHF I-III FC. Platelet aggregation activity was studied using a turbidimetric method using a laser analyzer (220 LA "NPF Biola", Russia). Platelet aggregation activity in platelet-rich plasma (BTP) was estimated by light transmission curves in % and average aggregate size in relative units (Rel. units), with the inducer epinephrine in concentrations of 2 and 10 mg/ml, with constant stirring at 800 rpm. The same parameters were evaluated byour ownproposed approach with a creation ofa "vortex" plasma flow, which were achieved by changing the mixing rate of BTP from 0 to 800 rpm. Aggregation data is presented as a median with an interquartile range (Me (Q1; Q3)). Statistical data processing was performed using SPSS packages (version 19). The differences were considered significant at a significance level of p < 0.05. Results. In patients with CHF, the indicators of spontaneous aggregation measured by the standard method were 3.1 (1.5; 4.0) % and 1.7 (1.1; 2.0) Rel. units. Under the conditions of a"vortex" flow, the aggregate size increased to 5.4 (3.2; 6.1) Rel. units(p = 0.04). The indicators of standard epinephrine-induced aggregation at a concentration of 2 mg/ml were 46.7 (35.8; 66.2) % and 15.0(11.4; 18.9) Rel. units, and when the mixing speed was changed from 0 to 800 rpm, the indicators increased to 52.7 (41.3; 76.5) % (p = 0.003) and 19.4 (17.3; 20.6) Rel. units(p = 0.04). In conditions of increased epinephrine concentration of 10 mg/ml, the indicators were 52.5 (41.9; 74.5) % (p = 0.03) and 15.8 (12.2; 18.4) Rel. units. Under the conditions of"vortex" flow, aggregation indicators were 75.4 (62.0; 80.5)% (p = 0.04), and the size of aggregates increased to 356.0 (230.5; 462.5) Rel. units. Conclusion. Standard methods for studying of platelet aggregation are not always sufficient to detect an increased pro-aggregative potential of platelets. The proposed method for creationof "vortex" flow conditions showed an increase in the size of platelet aggregates and the degree of aggregation against the background of increased epinephrine concentration in patients with chronic heart failure, which proves its effectiveness in detecting platelet hyperaggregation.

A comparative study on anti-inflammatory drug combinations in domestic pigeons with experimentally induced acute arthritis

The study compares the effect of one-time administration of nonsteroidal and/or steroidal anti-inflammatory combinations by topical or intramuscular (IM) routes to pigeons with monosodium urate (MSU)-induced arthritis. Forty-five adult domestic pigeons were assigned into nine equal groups: NC, negative control; PC, positive control with arthritis; sham, sham control; T1, meloxicam + hydrocortisone; T2, dexamethasone + piroxicam; T3, meloxicam + dexamethasone; T4, hydrocortisone + piroxicam; T5, dexamethasone + hydrocortisone; T6, meloxicam + piroxicam. Arthritis was also induced in T1 to T6 birds. Meloxicam and dexamethasone were administered by IM injection and the other drugs topically right after the induction of arthritis. Different drug combinations significantly decreased one-leg standing time. Induction of arthritis significantly increased TNF-α and IL-6 levels in synovial fluid and serum corticosterone and epinephrine in the PC group. Administration of drugs to birds of Groups T1 and T5 did not significantly change corticosterone concentration, while all different drug combinations decreased epinephrine level. Drug combinations that demonstrated better analgesic effect more strongly reduced serum epinephrine concentration. Meloxicam + hydrocortisone was the most effective combination in reducing inflammatory cytokines. In conclusion, one-time combination therapy with anti-inflammatory agents was effective in the acute management of inflammatory pain due to MSU-induced arthritis in pigeons, even by the topical route.

Adrenergic control of lipolysis in women compared with men

Data suggest women are more sensitive to the lipolytic action of epinephrine compared with men while maintaining similar glucoregulatory effects (Horton et al. J Appl Physiol 107: 200–210, 2009). This study aimed to determine the specific adrenergic receptor(s) that may mediate these sex differences. Lean women ( n = 14) and men ( n = 16) were studied on 4 nonconsecutive days during the following treatment infusions: saline (S: control), epinephrine [E: mixed β-adrenergic (lipolytic) and α2-adrenergic (antilipolytic) stimulation], epinephrine + phentolamine (E + P: mixed β-adrenergic stimulation only), and terbutaline (T: selective β2-adrenergic stimulation). Tracer infusions of glycerol, palmitate, and glucose were administered to determine systemic lipolysis, free fatty acid (FFA) release, and glucose turnover, respectively. Following basal measurements, substrate and hormone concentrations were measured in all subjects over 90 min of treatment and tracer infusion. Women had greater increases in glycerol and FFA concentrations with all three hormone infusions compared with men ( P < 0.01). Glycerol and palmitate rate of appearance (Ra) and rate of disappearance (Rd) per kilogram body weight were greater with E infusion in women compared with men ( P < 0.05), whereas no sex differences were observed with other treatments. Glucose concentration and kinetics were not different between sexes with any infusion. In conclusion, these data support the hypothesis that the greater rate of lipolysis in women with infusion of E was likely due to lesser α2 antilipolytic activation. These findings may help explain why women have greater lipolysis and fat oxidation during exercise, a time when epinephrine concentration is elevated.

Adrenergic Response to Maximum Exercise of Trained Road Cyclists

The aim of this study was to evaluate adrenergic responses in the peripheral blood of trained road cyclists at rest, at maximal intensity of incremental bicycle exercise test, and during 15 minutes of recovery, as well as the relationship between them. Competitive male road cyclists, in the pre-competitive phase of a season, mean age 21.7 ± 6.4 years, and BMI 20.7 ± 0.8 kg·m-2, performed an incremental test on a bicycle ergometer with unloaded cycling for 5 min, then increased the load to 40 W every 3 min, up to maximal exercise intensity. The plasma catecholamine concentrations (epinephrine, norepinephrine) and oxygen uptake were estimated. The expression of 132 genes related to the adrenergic system in leukocytes was measured. A statistically significant increase in plasma epinephrine concentration (p < 0.01) was observed in response to exercise. The mean of maximal oxygen uptake was 65.7 ± 5.5 ml·kg-1·min-1. The RGS2 gene expression was highest regardless of the test phase for all athletes. The effort had a statistically significant influence on ADRB2 and RAB2A expression. In addition, the RAB2A, ADM and HSPB1 expression level increased during recovery. We can conclude that plasma epinephrine concentration and genes related to the adrenergic system such as ADM, ADRB2, CCL3, GPRASP1, HSPB1, RAB2A, RGS2 and ROCK1 seem to have an influence on the response to high-intensity exercise in trained cyclists.

Central infusion of leptin does not increase AMPK signaling in skeletal muscle of sheep

In sheep, central leptin infusion reduces food intake and increases energy expenditure in adipose tissue and skeletal muscle. The mechanisms for these peripheral effects of central leptin in sheep are not known but, on the basis of rodent studies, may involve AMPK. In mice, central leptin acutely increases both skeletal muscle AMPK activation and glucose uptake. Thus, to investigate whether these effects exist in higher-order mammals, ovariectomized Corriedale ewes ( n = 4 per group) received a continuous lateral ventricular infusion (60 μl/h) of either leptin (50 μg/h) or artificial cerebrospinal fluid (aCSF; CON) for 8 days. Tritiated glucose (3-3H-glucose) was infused intravenously for calculation of whole body glucose turnover during both acute (6 h) and chronic (7–8 days) leptin/aCSF infusion. Muscle biopsies were also obtained. Leptin infusion reduced ( P < 0.05) food intake and body weight, and it also increased plasma epinephrine concentration at 6 h and 7 days, suggesting increased sympathetic nerve activity. Despite this, and in contrast to rodent studies, central leptin infusion did not increase skeletal muscle AMPKα Thr172 phosphorylation or ACCβ Ser221 phosphorylation. Surprisingly, the glucose rate of appearance (glucose Ra) and rate of disappearance (glucose Rd) were reduced by both acute and chronic leptin infusion. Direct infusion of the AMPK activator 5-aminoimidazole-4-carboxyamide-ribonucleoside (AICAR) into the femoral artery increased skeletal muscle AMPK phosphorylation. In conclusion, although central leptin infusion in sheep caused the predicted reduction in food intake and increases plasma epinephrine concentration, it had no effect on AMPK activation in skeletal muscle and actually reduced glucose disposal. This suggests that there are species differences in the peripheral responses to central leptin infusion.