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14792. Changes in smooth muscle cell pH during hypoxic pulmonary vasoconstriction: a possible role for ion transporters
- Creator:
- Madden, J. A., Kelelr, P. A., and Kleinman, J. G.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, 14, and 612
- Language:
- English
- Description:
- Hypoxic pulmonary vasoconstriction (HPV) occurs in smooth muscle cells (SMC) from small pulmonary arteries (SPA) and is accompanied by increases in free cytoplasmic calcium ([Ca2+]i) and cytoplasmic pH (pHi). SMC from large pulmonary arteries (LPA) relax during hypoxia, and [Ca2+]i and pHi decrease. Increases in pHi and [Ca2+]i in cat SPA SMC during hypoxia and the augmentation of hypoxic pulmonary vasoconstriction by alkalosis seen in isolated arteries and lungs suggest that cellular mechanisms, which regulate inward and outward movement of Ca2+ and H+, may participate in the generation of HPV. SMC transport systems that regulate pHi include the Na+-H+ transporter which regulates intracellular Na+ and H+ and aids in recovery from acid loads, and the Na+-dependent and Na+-independent Cl-/HCO3- transporters which regulate intracellular chloride. The Na+-dependent Cl-/HCO3- transporter also aids in recovery from acidosis in the presence of CO2 and HCO3-. The Na+-independent Cl-/HCO3- transporter aids in recovery from cellular alkalosis. The Na+-H+ transporter was present in SMC from SPA and LPA of the cat, but it seemed to have little if any role in regulating pHi in the presence of CO2 and HCO3-. Inhibiting the Cl-/HCO3- transporters reversed the normal direction of pHi change during hypoxia, suggesting a role for these transporters in the hypoxic response. Future studies to determine the interaction between pHi, [Ca2+]i and HPV should ascertain whether pHi and [Ca2+]i changes are linked and how they may interact to promote or inhibit SMC contraction., J. A. Madden, P. A. Keller, J. G. Kleinman., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14793. Changes in some photosynthetic parameters in pea plants after treatment with cobalt
- Creator:
- Angelov, M., Tsonev, T., Dobrinova, K., Velikova, V., and Stoyanova, T.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- CO2 (40, 200, 400 loM) was added to the root systém of 10-d-old pea plants (Pisum sativum L. cv. Ran). The Co2'''-excess caused a reduction in the plant fresh and diy masses and water and chlorophyll contents. The rates of photosynthesis and transpiration decreased, while proline content and stomata resistance increased. The dramatic effect of Co2+-toxicity was expressed both in an inhibition of ribulose 1,5- bisphosphate (RuBP) carboxylase activity and a stimulation of RuBP-oxygenase and phosphoenolpyruvate carboxylase activities on the 4‘h day of cnltivation of plants in a solution of 400 pM C6^*.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14794. Changes in stomatal characteristics and photochemical efficiency during leaf development in six species of Sorbus
- Creator:
- Čaňová, I., Ďurkovič, J., Hladká, D., and Lukáčik, Ivan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, phenological stages, photochemical efficiency, Sorbus chamaemespilus, 2, and 58
- Language:
- Multiple languages
- Description:
- Measurements of Sorbus stomata size and density, maximal photochemical efficiency of photosystem II (Fv/Fm), variable-to-initial fluorescence ratio (Fv/F0) and potential electron acceptor capacity (‘area’) were performed during leaf development in four parental diploid species, S. aria, S. aucuparia, S. chamaemespilus, S. torminalis, and two hybrid species, S. hazslinszkyana and S. intermedia. In fully expanded mature leaves, stomata lengths and densities were significantly larger in the shrub S. chamaemespilus than in the five tree species. The best performance of both the Fv/Fm and the Fv/F0 ratio was recorded in S. intermedia, whereas S. chamaemespilus had the highest value of ‘area’. From a physiological point of view, the results of this study showed that the photosystem II reaction centers remained intact functionally through all phenological stages of leaf expansion for all examined species of Sorbus., I. Čaňová ... [et al.]., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14795. Changes in the acoustically evoked activity in the inferior colliculus of the rat after functional ablation of the auditory cortex
- Creator:
- Nwabueze-Ogbo, F. C., Jiří Popelář, and Syka, J.
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Auditory cortex, Inferior colliculus, Corticotectal pathways, Functional ablation, Rat, 14, and 612
- Language:
- English
- Description:
- The role of the cortico-tectal pathways in the processing of auditory signals was investigated by recording the click-evoked responses and extracellular multiple unit activity in the inferior colliculus (IC) after functional ablation of the auditory cortex (AC) by local intracortical application of a sodium channel blocker, tetrodotoxin (TTX). Click-evoked IC responses (IC-ER) and multiple unit activity in response to tone bursts were recorded with implanted electrodes in the IC of rats lightly anaesthetized with xylazine. Neural activity was recorded before and after the application of TTX into the ipsilateral auditory cortex (AC) through three implanted cannulas in a total dose of 30 ng. The functional status of the AC was monitored by recording click-evoked middle latency responses from a ball electrode implanted on the AC. During inactivation of the AC, IC-ER amplitudes were either increased (48 % of the cases), decreased (32 % of the cases) or not evidently changed (20 % of the cases). Corresponding effects were observed in the firing rate of IC neurons. Functional ablation of the AC also resulted in a significant prolongation of the latencies of individual waves of the IC-ER. However, the discharge pattern of the multiple unit responses, response thresholds and tuning were not altered during AC inactivation. IC neural activity recovered within several hours, and maximally during 2 days. The results reveal principles of the interaction of cortico-tectal pathways with IC neuronal activity., F. C. Nwabueze-Ogbo, J. Popelář, J. Syka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14796. Changes in the calling behaviour of female Spodoptera littoralis (Lepidoptera: Noctuidae) as a function of body weight and adult feeding
- Creator:
- Sadek, Medhat M.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Zoologie, zoologie, entomologie, Lepidoptera, Noctuidae, Spodoptera littoralis, body weight, calling behaviour, adult food, 2, and 59
- Language:
- English
- Description:
- Because nutrients accrued during larval stages represent the major limiting factor for egg production, the use of adult feeding to enhance the reproductive output in moths is considered to be largely weight-dependent. It is hypothesized, however, that feeding by adults could be adaptive and an effective means of increasing their reproductive success. In order to test this, the calling behaviour of Spodoptera littoralis females that differed in body weight and whether they had fed or not were recorded. Two experiments were carried out. In the first, the calling behaviour of food-deprived females of different body weights was recorded. A strong positive correlation was found between body weight at emergence and the total duration of calling of females on the second to the fifth night after emergence. In the second experiment, groups of female moths that varied in body weight were given access to water or sucrose. Feeding on sucrose significantly reduced the pre-calling period and increased the total time spent calling on the six nights after emergence. The increase in time spent calling associated with ingesting sucrose were proportionately similar for both small and large females, implying that feeding by adults can result in an increase in the time spent calling by moths irrespective of larval nutritional status. Female longevity was also correlated with moth weight at emergence and/or sucrose availability. It is concluded that it is advantageous for female S. littoralis to be large and/or have access to sucrose-rich food in the adult stage as they can spend more time attracting a mate, which increases their chances of mating in early adult life, and their longer adult life may indirectly result in an increase in fecundity., Medhat M. Sadek., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
14797. Changes in the composition of fatty acids and lipofuscin-like pigments during development of rat heart
- Creator:
- Wilhelm, J., Joško Ivica, Veselská, Z., Jiří Uhlík, and Luděk Vajner
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, mastné kyseliny, volné radikály, srdce, fatty acids, free radicals, heart, development, lipofuscinlike pigments, 14, and 612
- Language:
- English
- Description:
- Postnatal heart development is characterized by critical periods of heart remodeling. In order to characterize the changes in the lipophilic fraction induced by free radicals, fatty acids and t heir oxidized products, lipofuscin -like pigments (LFP), were investigated. Fatty acids were analyz ed by gas chromatography and LFP were studied by fluorescence techniques. A fluorophore characterized by spectral methods was further resolved by HPLC. Major changes in the composition of fatty acids occurred immediately after birth and then during maturation. Fluorescence of LFP changed markedly on postnatal days 1, 4, 8, and 14, and differed from the adult animals. LFP comprise several fluorophores that were present since fetal state till adulthood. No new major fluorophores were formed during development, just the abundances of individual fluorophores have been modulated which produced changes in the shape of the spectral arrays. HPLC resolved the fluorophore with excitation maximum at 360 nm and emission maximum at 410 nm. New chromatographically distinct species appeared immediately on postnatal day 1, and then on days 30 and 60. Consumption of polyunsaturated fatty acids immediately after birth and subseque nt formation of LFP suggests that oxidative stress is involved in normal heart development., J. Wilhelm, J. Ivica, Z. Veselská, J. Uhlík, L. Vajner., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14798. Changes in the contents of the photosynthetic electron carriers, RNAse activity and membrane permeability, triggered by excess copper in rice
- Creator:
- Lidon, F. C. and Henriques, F. S.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Rice (Oryza sativa L.) plants were grown in nutríent solutíon containing concentrations of Cu vaiying from deficiency to toxicity [0.002-6.25 g(Cu) m"^]. Shoot contents of Cu, Mn and Fe were measured as well as the concentrations of plastocyanin (PC), plastoquinone (PQ) and cytochromes (cyt) f, 6553, 6-559up, and b- 559hp. While Cu concentration increased wilh increasing levels of metal in the solutíon, Mn and Fe concentrations progressively decreased after Cu treatments higher than 0.05 g m‘3. On a chlorophyll basis, the contents of PC and cyt/decreased after the 0.01 g(Cu) m'^ Cu treatonent, while the contents of cyt f>-559Lp and b- 559hp did not show any apparent conelatíon, and the PQ concentration sharply increased with increasing Cu toxicity. Membrane permeability and acid RNAse activity were enhanced with increasing Cu concentration.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14799. Changes in the density of nitrergic neurons in the hippocampus of rats following kainic acid and melatonin administration
- Creator:
- Jain, A., Sharma, D., Suhalka, P., Sukhwal, P., and Bhatnagar, M.
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, NADPH-diaphorase, kainic acid, melatonin, nitric oxide, hippocampus, 14, and 612
- Language:
- English
- Description:
- Nitric oxide (NO) may play a role in the pathophysiology of excitotoxicity. It is also possible that increase in Ca2+ overload and NO-mediated events are involved in neuronal loss during excitotoxicity. Using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, we have investigated the effects of melatonin on NADPH-d positive hippocampal neurons after kainic acid (KA) induced excitotoxicity in female rats of Wistar strain. Cytosolic Ca2+ (free calcium) in all the respective experimental groups was also studied. Kainic acid was administered, with a single dose of 10 mg/kg/bw (body weight) to the animals. KA treated rats were given melatonin at a dose of 20 mg/kg/bw (for 14 day). On the last day of treatment, animals were transcardially perfused with 4 % paraformaldehyde under deep thiopental anaesthesia. Cryostat sections (20 µm) were cut and stained for NADPH-d positive neurons. KA exposed animals showed a significantly increased number of NADPH-d positive neurons in the dorsal and ventral blade of the dentate gyrus (DG), hilus, CA1 and CA3 area of hippocampus, with a parallel increase in intracellular free Ca2+ ion concentration, as compared to the control group. KA + melatonin-treated animal groups showed reduced number of NADPH-d positive neurons in DG, hilus, CA1 and CA3 areas and a decline in cytosolic Ca2+ concentration, as compared to KA treated group. Our study suggests that the enhanced levels of cytosolic Ca2+ and nitric oxide (NO) play an important role in kainate induced excitotoxicity. Inhibition of NO production may be another means whereby melatonin can reduce oxidative damage and seems to play important role in neuroprotection., A. Jain, ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
14800. Changes in the Development of Uterine Pinopodes in Steroid Hormone Supplemented Cycles
- Creator:
- Oborná, I., Novotný, R., Březinová, J., Petrová, P., Lichnovský, V., and Fingerová, H.
- Type:
- article, model:article, and TEXT
- Subject:
- Endometril receptivity, Pinopodes, Scanning electron microscopy, and Steroid hormones
- Language:
- English
- Description:
- The endometrium acquires the ability to implant a hatched blastocyst only within a specific time termed the receptive phase. Ovarian steroid hormones are essential for structural and functional changes that prepare the endometrium to be receptive. Pinopodes have been suggested to be markers of uterine receptivity. The aim of this study was to compare the pinopode expression and serum levels of ovarian steroid hormones in the mid-luteal phase of the natural cycle and in a “mock” cycle in the same subject. Sequentional endometrial biopsies within 48 hours were obtained from women in the mid-luteal phase (ovulation +5, ovulation +7) of the natural cycle and in the “mock” cycle (progesterone supplementation +5 and +7). Biopsies were examined under a scanning electron microscope for pinopode detection. The expression of pinopodes was similar in both cycles, where pinopodes covered about 5 % of the endometrial surface. The developmental stages were also similar with a slight increase of fully developed pinopodes in both samples in the “mock” cycles. Our findings suggest that hormonal preparation of the endometrium do not change the timing of pinopode expression.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public