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31332. The effects of adrenergic agonists on intraocular pressure and on adenylyl cyclase activity of ciliary processes in pigmented rabbits
- Creator:
- Čepelík, J., Dědina, M., and Hynie, S.
- Type:
- article, model:article, and TEXT
- Subject:
- adenylyl cyclase, adrenergic agonists, ciliary processes, desensitization, and intraocular pressure
- Language:
- English
- Description:
- The effects of /¿-adrenergic agonists isoprenaline, fenoterol and clenbuterol on the activity of adenylyl cyclase from ciliary processes and on intraocular pressure were examined in pigmented rabbits. Isoprenaline, fenoterol and clenbuterol stimulated adenylyl cyclase activity in vitro, but clenbuterol behaved as a partial agonist. Preincubation of ciliary processes with any of these three drugs led to the heterologous desensitization of adenylyl cyclase to the stimulatory effects of beta-adrenergic agonists or vasoactive intestinal peptide (VIP). This desensitization was dose-dependent and was expressed mainly as a decrease of the highest effects of stimulatory drugs. The exact mechanism of this phenomenon is not yet known. After topical administration, all three tested /¿-adrenergic agonists decreased intraocular pressure with approximately the same intensity. The relationship between ocular hypotensive effects of /¿-adrenergic agonists and their effects on adenylyl cyclase of ciliary processes is discussed. It is concluded that ocular hypotensive effects of adrenergic agonists and other drugs stimulating adenylyl cyclase cannot be explained simply by stimulation or desensitization of adenylyl cyclase of ciliary processes.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31333. The Effects of Cardiopulmonary Bypass with Hollow Fiber Membrane Oxygenator on Blood Clotting Measured by Thromboelastography
- Creator:
- Michal Horáček and Karel Cvachovec
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Blood clot, Thromboelastography, Cardiopulmonary bypass, Bleeding, Oxygenator, 14, and 612
- Language:
- English
- Description:
- In cardiac surgical patients we investigated the effects of cardiopulmonary bypass (CPB) with a hollow fiber membrane oxygenator on blood clotting measured by thromboelastography (TEG). We found only a minimal change in the strength of blood clot described either by the TEG parameter MA (maximum amplitude) or by the shear modulus G calculated from MA. After CPB there was also a significant tendency towards hypercoagulation as defined by shortened parameters R, K and increased ?-angle. After comparison with published data obtained in cardiac surgical patients using a bubble oxygenator we conclude that currently used extracorporeal technology exerts a less negative influence on blood clotting than had been conceived previously., M. Horáček, K. Cvachovec., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31334. The effects of condensed tannins extracted from different plant species on egg hatching and larval development of Teladorsagia circumcincta (Nematoda: Trichostrongylidae)
- Creator:
- Molan, Abdul-Lateef and Faraj, Abbas Mohamed
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Teladorsagia circumcincta, egg hatching, larval development, and condensed tannins
- Language:
- English
- Description:
- The effects of condensed tannins (CTs) extracted from five species of plants on egg hatching and larval development of Teladorsagia circumcincta (Stadelmann, 1894) (syn. Ostertagia circumcincta) were evaluated using in vitro bioassays. The extracts of CTs were obtained from Lotus pedunculatus (LP), Lotus corniculatus (LC), Dorycnium pentaphyllum (DP), Dorycnium rectum (DR) and Rumex obtusifolius (RO). The results of egg hatching assay showed that about 53%, 68%, 51%, 60% and 46% of the eggs hatched when in vitro incubations contained 900 mg/ml of CTs from LP, LC, DP, DR and RO, respectively (P< 0.001 relative to control incubation), while in control incubations (no CT added) 87% of the eggs hatched. In the larval development assay, development was allowed to proceed for 7 days, by which time 89% of the hatched larvae in control wells (no CTs) had reached the infective third stage (L3). In incubations containing 200 mg CT from LP, LC, DP, DR and RO/ml, about 8%, 15%, 14%, 8% and 4% of the eggs attained full development to L3 larvae, respectively (P< 0.001 relative to control incubation). Only 1% of the eggs were able to develop to L3 larvae in incubations containing 400 mg CT extracted from LC/ml, whilst in the incubations containing the same concentration of other CTs the eggs were not able to develop to L3 larvae. It seems that CTs are not only slowing down the larval development but also kill the undeveloped larvae. At 400 mg/ml, for example, CT from LP, LC, DP, DR and RO killed 67%, 48%, 68%, 93% and 91% of first-stage (L1) and second-stage (L2) larvae, respectively. This study shows that CTs are able to disrupt the life cycle of nematodes.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31335. The effects of different types of exercise on circulating irisin levels in healthy individuals and in people with overweight, metabolic syndrome and type 2 diabetes
- Creator:
- Parada-Sánchez, Sandra G., Macias-Cervantes, Maciste H., Pérez-Vázquez, Victoriano, and Vargas-Ortiz, Katya
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- exercise, FNDC5, metabolic syndrome, obesity, and type 2 diabetes
- Language:
- English
- Description:
- Irisin is a myokine secreted during exercise. It has drawn the attention of researchers as it regulates several effects of exercise that are considered beneficial. It has also been proposed as a therapeutic tool to treat metabolic disorders. In recent years, the effect of different types of training on circulating irisin has been studied in large populations. An overall beneficial result has been shown, however, the outcome of the investigations has raised some controversy. Herein we evaluated the existing literature on the effects of different types of training on the circulating irisin levels in healthy subjects and in those displaying different metabolic condition. We conducted queries in the PubMed and Web of Science databases for literature published between January 2010 and January 2021. Thirty-seven original articles were retrieved and they were included in this review. Any letter to the editor, meta-analyses, reviews, and systematic review articles were excluded. From these 37 articles, 19 of them reported increased levels of circulating irisin. The interventions encompassed aerobic, resistance, combined, circuit, and interval training types. Such increase of circulating irisin was reported for healthy subjects and for those displaying different metabolic condition. A training that is steadily kept with a moderate to high intensity, including that characterized by brief highly intense intervals, were distinguishable from the rest. Nevertheless, the training effectiveness as evaluated by the increased circulating irisin levels depends on the subject’s metabolic condition and age.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31336. The effects of drought stress and leaf ageing on leaf photosynthesis and electron transport in photosystem 2 in sweet potato (Ipomoea batatas Lam.) cultivars
- Creator:
- Haimeirong and Kubota, F.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, cultivar differences, dry mass, leaf area, non-photochemical quenching, photorespiration, quantum yield, and stomatal conductance
- Language:
- Multiple languages
- Description:
- Of the four tested sweet potato cultivars having different features in growth and yield, cv. Koganesengan (KOG) was sustainable in photosynthetic activity through young to aged leaves under drought. One of the causes for this phenomenon may be stomatal conductance (g s) of this cultivar that was relatively high in both aged and drought-imposed leaves. In these leaves the non-photochemical quenching (NPQ) was low and the quantum yield of photosystem 2 (Φe) was high, compared to those of the other cultivars. This helps to prevent excessive accumulation of chemical energy in leaves and a decrease in photoinhibition damage to the photosynthetic function, by which KOG sustains a relatively high photosynthetic activity under the drought and alleviates functional deterioration caused by leaf age. and Haimeirong, F. Kubota.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31337. The effects of enhanced UV-B radiation on photosynthetic and biochemical activities in super-high-yield hybrid rice Liangyoupeijiu at the reproductive stage
- Creator:
- Yu, G. H., Li, W., Yuan, Z. Y., Cui, H. Y., Lv, C. G., Gao, Z. P., Han, B., Gong, Y. Z., and Chen, G. X.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, chloroplast ultrastructure, gas exchange, light reaction, photosynthesis, Rubisco, UV-B radiation, 2, and 58
- Language:
- Multiple languages
- Description:
- a1_We investigated the light reactions, CO2 assimilation, but also the chloroplast ultrastructure in the upper three functional leaves (flag, 2nd, and 3rd leaves) of the Chinese super-high-yield hybrid rice (Oryza sativa L.) Liangyoupeijiu (LYPJ) with ultraviolet-B (UV-B) treatment during reproductive development. Photosynthetic parameters showed that the upper 3 functional leaves of LYPJ entered into senescence approximately 15 days after flag leaf emergence (DAE). Leaves in UV-B treatment exhibited greater efficiency in absorbing and utilizing light energy of photosystem II (PSII), characterized by higher chlorophyll (Chl) content and the whole chain electron transport rate (ETR). However, UV-B radiation reduced activities of Ca2+-ATPase and photophosphorylation. The significantly decreased activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) was greatly associated with the decline in photosynthetic efficiency. The net photosynthetic rate (PN) and stomatal conductance (gs) suffered strong reductions before 25 DAE, and afterwards showed no significant difference between control and treatment. UV-B treatment delayed chloroplasts development of flag leaves. Chloroplast membranes later swelled and disintegrated, and more stromal thylakoids were parallel to each other and were arranged in neat rows, which might be responsible for better performance of the primary light reaction. It is likely that accumulation of starch and an increase in the number of lipid droplet and translucent plastoglobuli were results of an inhibition of carbohydrate transport. Our results suggest that long-term exposure to enhanced UV-B radiation was unlikely to have detrimental effects on the absorption flux of photons and the transport of electrons, but it resulted in the decrease of photophosphorylation and Rubisco activation of LYPJ., a2_The extent of the damage to the chloroplast ultrastructure was consistent with the degree of the inhibition of photosynthesis., G. H. Yu ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31338. The Effects of Gender and Obesity on Myocardial Tolerance to Ischemia
- Creator:
- Clark, C., Smith, W., Lochner, A., and Du Toit, E.F.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, Obesity, Gender, Myocardial infarction, 14, and 612
- Language:
- English
- Description:
- Obesity is increasing at an alarming rate globally. Several studies have shown that premenopausal women have a reduced risk of CV disease and a reduced myocardial susceptibility to ischemia/reperfusion injury. The effect of obesity on myocardial tolerance to ischemia in women has not been established. To determine how obesity affects myocardial susceptibility to ischemia/reperfusion injury in both males and females, we fed male and female Wistar rats a high caloric diet (HCD) or a control rat chow diet (CD) for 18 weeks. Rats were subsequently fasted overnight, anesthetized and blood was collected. In separate experiments, 18-week-fed (HCD and CD) rats underwent 45 min in vivo coronary artery ligation (CAL) followed by 2 hours reperfusion. Hearts were stained with TTC and infarct size determined. Both male and female HCD fed rats had increased body and visceral fat weights. Homeostasis model assessment (HOMA) index values were 13.95±3.04 for CD and 33.58±9.39 for HCD male rats (p<0.01) and 2.98±0.64 for CD and 2.99±0.72 for HCD fed female rats. Male HCD fed rats had larger infarct sizes than CD fed littermates (43.2±9.3 % vs. 24.4±7.6 %, p<0.05). Female HCD and CD diet fed rats had comparable infarct sizes (31.8±4.3 % vs. 23.9±3.3 %). We conclude that male rats on the HCD became viscerally obese, dyslipidemic and insulin-resistant, while female HCD fed rats became viscerally obese without developing dyslipidemia or insulin resistance. Obesity increased myocardial infarct size in males but not the females., C. Clark ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31339. The effects of head cooling on endurance and neuroendocrine responses to exercise in warm conditions
- Creator:
- Ansley, L., Marvin, G., Sharma, A., Kendall, M. J., Jones, D. A., and Bridge, M. W.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, hypertermie, tělesná cvičení, únava, physiology, hyperthermia, exercises, fatigue, prolactin, head cooling, 14, and 612
- Language:
- English
- Description:
- The present study investigated the effects of head cooling during endurance cycling on performance and the serotonergic neuroendocrine response to exercise in the heat. Subjects exercised at 75 % VO2max to volitional fatigue on a cycle ergometer at an ambient temperature of 29±1.0 °C, with a relative humidity of approximately 50 %. Head cooling resulted in a 51 % (p<0.01) improvement in exercise time to fatigue and Borg Scale ratings of perceived exertion were significantly lower throughout the exercise period with cooling (p<0.01). There were no indications of peripheral mechanisms of fatigue either with, or without, head cooling, indicating the importance of central mechanisms. Exercise in the heat caused the release of prolactin in response to the rise in rectal temperature. Head cooling largely abolished the prolactin response while having no effect on rectal temperature. Tympanic temperature and sinus skin temperature were reduced by head cooling and remained low throughout the exercise. It is suggested that there is a co-ordinated response to exercise involving thermoregulation, neuroendocrine secretion and behavioural adaptations that may originate in the hypothalamus or associated areas of the brain. Our results are consistent with the effects of head cooling being mediated by both direct cooling of the brain and modified cerebral artery blood flow, but an action of peripheral thermoreceptors cannot be excluded., L. Ansley, G. Marvin, A. Sharma, M. J. Kendall, D. A. Jones, M. W. Bridge., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
31340. The Effects of Housing Prices on Income Inequality in Urban China
- Creator:
- Zhang, Chuanyong and Zhang, Fang
- Type:
- article, model:article, and TEXT
- Subject:
- housing, housing prices, income inequality, and regional disparities
- Language:
- English
- Description:
- This paper explores the effects of housing prices on income inequality in urban China. The authors use China's interprovincial panel data for the period between 1999 and 2011 and find that there is a significant positive association between housing prices and the Gini coefficient of the income of urban residents, and that there are remarkable regional disparities.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public