Gender differences in residual effect of prior drop jumps on oxygen uptake during heavy cycling exercise.

BACKGROUND AND OBJECTIVE: Unaccustomed eccentric or eccentric-concentric exercise leaves us stiff and sore the next day and can cause muscle damage. The data about the residual effect of prior eccentric-concentric exercises on oxygen uptake (VO2) during constant cycling exercise in women or the data about differences of such effect between genders are scarce. Therefore, the aim of this study was to assess differences of the residual effect of PDJ on VO2 during HCE and indirect muscle damage parameters between women and men. MATERIALS AND METHODS: The study aimed to asses differences of the residual effect of prior drop jumps (PDJ) on VO2 during heavy cycling exercise (HCE) and indirect muscle damage parameters between men (n=8) and women (n=11). On four different days participants performed one incremental cycling exercise and three HCE (control [CON], 45min [45' PDJ] and 24h [24h PDJ] after 100 drop jumps). The intensity of HCE was set to work rate corresponding to 50% of the difference between the second and the first ventilatory thresholds which were determined analyzing pulmonary gas exchange parameters during incremental cycling exercise. Capillary blood samples were collected in order to measure blood lactate concentration immediately after HCE and serum creatine kinase (CK) activity 24h after PDJ. Subjects rated perceived exertion and delayed onset muscle soreness (DOMS) using 20 and 10 point scales, respectively. RESULTS: VO2 at 3-6min of HCE performed 45' after PDJ was significantly increased as compared to CON HCE only in the male group. Both men and women felt moderate muscle pain. CK activity was significantly increased 24h after PDJ in the male group. Both during HCE 45' PDJ and 24h PDJ, the significant positive correlation was observed between relative changes of VO2 during steady state of HCE and CK activity only in the male group. CONCLUSIONS: Prior eccentric-concentric exercise of thigh muscles (100 drop jumps) accelerates VO2 kinetics at the start and increases VO2 during steady state of heavy cycling only in the male group. So, prior exercise of such type has a higher negative impact on cycling economy in men than in women and this might be related to greater muscle damage and fatigue in physically active male persons after plyometric exercise.

Monitoring changes in heart tissue temperature and evaluation of graft function after coronary artery bypass grafting surgery.

Thermography is a relatively new contact-free method used in experimental and clinical studies and in cardiovascular surgery to investigate the myocardium and coronary artery function. Objects of complex study included mongrel dogs and patients with coronary artery disease who underwent cardiac surgery. For active dynamic thermography, we used a thermovision camera "A20V" (FLIR Systems, USA). Our data indicate that both experimental and clinical study performed on beating hearts could be an important approach to interoperation inspection of autovenous graft function. An infrared camera also can be successfully used to determine the extent of ischemic damage to the myocardium, heart, and blood vessels during surgery as a significant prognostic tool for evaluating outcome after cardiac operation.

Free radical-scavenging activities of Crataegus monogyna extracts.

UNLABELLED: The aim of this study was to investigate antiradical activity of aqueous and ethanolic hawthorn fruit extracts, their flavonoids, and flavonoid combinations. MATERIAL AND METHODS: Total amount of phenolic compounds and the constituents of flavonoids were determined using a high-performance liquid chromatography. The antioxidant activity of Crataegus monogyna extracts and flavonoids (chlorogenic acid, hyperoside, rutin, quercetin, vitexin-2O-rhamnoside, epicatechin, catechin, and procyanidin B(2)) quantitatively was determined using the method of spectrophotometry (diphenyl-1-picrylhydrazyl (DPPH.) radical scavenging assay and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid)(ABTS.+) radical cation decolorization assay). The level of tyrosine nitration inhibition was determined using a high-performance liquid chromatography. RESULTS: Ethanolic hawthorn fruit extract contained 182+/-4 mg/100 mL phenolic compounds, i.e. threefold more, as compared to aqueous extract. The antioxidant activity according to DPPH. reduction in the ethanolic extracts was higher 2.3 times (P<0.05). The ABTS.+ technique showed that the effect of ethanolic extracts was by 2.5 times stronger than that of aqueous extracts. Tyrosine nitration inhibition test showed that the effect of ethanolic extracts was by 1.4 times stronger than that of aqueous extracts. The investigation of the antiradical activity of the active constituents in aqueous and ethanolic extracts revealed that epicatechin and catechin contribute to radical-scavenging properties more than other components. Procyanidin B(2) only insignificantly influenced the antiradical activity of the extracts. CONCLUSION: Both aqueous and ethanolic hawthorn extracts had antiradical activity, but ethanolic extract had stronger free radical-scavenging properties, compared to the aqueous extract. The antioxidant activity of the studied preparations was mostly conditioned by epicatechin and catechin. The individual constituents of both extracts had weaker free radical-scavenging properties than the combination of these substances did.

[The diuretic effect of cornflower water extract]. / Rugiageliu ziedu vandenines istraukos diurezinis veikimas.

UNLABELLED: The objective of this study was to evaluate and compare the effect of cornflower water extract and hydrochlorothiazide on diuresis, Na(+) and K(+) excretion, and the changes in the prostaglandin E(2) and kinins levels in the blood plasma. MATERIAL AND METHODS: Male Wistar rats were used in all experiments. Animals were divided into nine groups. Diuretic activity was investigated according to the technique proposed by E. B. Berchin; urinary electrolyte contents were analyzed by flame photometry. Prostaglandin E(2) content was measured by radioimmunoassay using (3)H isotopes, kinins--by enzymatic methods. RESULTS: It has been established that in male rats, receiving hydrochlorothiazide, the volume of urine excreted two and four hours after the administration of the drug was by 18% and 17%, respectively, higher as compared to the rats that were given cornflower water extract (P<0.05). The diuretic effect of cornflower water extract was noted in the animal group receiving this extract as compared to the control group: after two hours, the volume of urine excreted increased from 2.03+/-0.03 mL to 2.44+/-0.04 mL and after four hours--from 3.88+/-0.07 mL to 5.35+/-0.1 mL. Administration of hydrochlorothiazide under the load of salts and water resulted in a higher excretion of sodium and potassium as compared to the effect of cornflower water extract. The highest prostaglandin levels were found in the blood plasma of the animals receiving hydrochlorothiazide. Under the load of salts and water, a 13% and 15% increase, respectively, in the amount of prostaglandins was observed in the animals that were given cornflower water extract compared to the control animals (P<0.05). The greatest increase in the amount of kinins was found in the groups of animals that were given hydrochlorothiazide under the load of salts and water (14% and 22%, respectively). Kinin levels did not differ statistically significantly between the control group and the groups receiving cornflower water extract. CONCLUSION: Cornflower water extract possesses diuretic activity, but its effect was lower than that of hydrochlorothiazide.

[Trace elements, cholesterol and ultrastructural alterations of aorta in hypodynamic stress]. / Mikroelementu, cholesterolio ir aortos intimos strukturiniai pakitimai esant hipodinamijai.

Hypodynamic stress of 48-day duration was provoked by permanent and periodically recurrent intervention (the hypodynamics periodically exchanged to physically activity) for Chinchilla rabbits (weight 2.5-3.0 kg) (n=19) by placing them in metal hutches according to B. V. Fiodorow. Rabbits (n=10) of the control group which had no intervention were kept in vivarium conditions. The concentration of trace elements (Zn, Mn, Cu) in the blood plasma and thoracic aorta was assessed by atomic absorption spectrophotometer (Perkin-Elmer 503, USA). The level of cholesterol was determined by enzymatic analysis. Ultrathin sections of thoracic aorta were examined with electron microscope "Tesla BS-500" (Italy). After 48 days of permanent hypodynamic stress the concentration of Zn and Mn in blood plasma of rabbits was found to be significantly decreased while the cholesterol and Cu level was greater than before the stress. In case of permanent stress significant decrease also was found in the concentration of Cu and Mn in aorta in comparison with that in the case of periodically recurrent stress. The mentioned changes of the trace elements and cholesterol concentration in tissues of rabbits in case of permanent hypodynamic stress were accompanied by ultrastructural alterations in endothelium--desintegration of cells, and winding and fragmentation of internal elastic lamina, accumulation of lipids. In case of periodically recurrent hypodynamic stress of the some duration these changes were less expressed.

[Characteristics of general anesthesia in the investigation of heart electrophysiology]. / Bendrosios anestezijos ypatumai tyrinejant sirdies elektrofiziologines savybes.

Investigating electrophysiological properties of the heart under acute experimental conditions, dogs are affected by operative stress because of traumatic surgical manipulations, so investigations are performed under general anaesthesia. Many anaesthetics together with their main function have desintegrating influence on autonomic regulation mechanisms. That is why anaesthetics used during experiments must fullfil such requirement--have minimal influence on autonomic nervous system (ANS) and heart conductivity system (HCS) interaction parameters or to make this influence insignificant. We did not found common anaesthesia methodics that can fullfil that requirements, so we decided to prepare new common anaesthesia methodics, which could fullfil requirements mentioned above. We choose medicaments according to their pharmacokinetics and pharmacodynamics action. For methodics optimization we've used 2 groups of dogs (mongrel dogs males weight 7-15 kg) (n = 10). We've applied different anaesthesia schemas on each group. Premedication in the I-st group was performed with intramuscle (i.m.) combination of diazepam, ketamine and phentanyl and for anaesthesia continuous intravenous (i.v.) infusion of thiopental and ketamine. In II-nd group premedication was performed with i.m. injection of ketamine/phentanyl combination and for anaesthesia--continuous i.v. infusion of thiopental. Induction in both groups was performed with i.v. thiopental injection. Suitability of premedication and anaesthesia was valued by adequativity of haemodynamics (heart rate 1/min) and surgical manipulations during experiments. Our conclusion is: investigating interaction of ANS and HCS methodics used in the I-st group of dogs is more suitable.