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Start Over Format svazek Subject human physiology

72. Fluoride Plus Aluminum: Useful Tools in Laboratory Investigations, but Messengers of False Information

Creator:
Anna Strunecká, Strunecký, O., and Patočka, J.
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Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Aluminum, Fluoride, Aluminofluoride complexes, G-protein, Second messenger, 14, and 612
Language:
English
Description:
Aluminofluoride complexes (AlFx) form spontaneously in aqueous solutions containing fluoride and traces of aluminum ions and appear to act as phosphate analogs. These complexes have become widely utilized in laboratory investigations of various guanine nucleotide-binding proteins. Reflecting on many laboratory studies, a new mechanism of fluoride and aluminum action on the cellular level is being suggested. The long-term synergistic effects of these ions in living environment and their hidden danger for human health are not yet fully recognized., A. Strunecká, O. Strunecký, J. Patočka., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

73. Functional Cross-talk of Ca2+-Mobilizing Endothelin Receptors in C6 Glioma Cells

Creator:
Radek Malík, Vlašicová, K., and Aleksi Šedo
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article, studie, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Endothelin receptor, Glioma, Calcium signaling, Cell differentiation, 14, and 612
Language:
English
Description:
There are conflicting results concerning the receptor subtype(s) involved in calcium-mediated endothelin signaling in the glial cells. In order to elucidate the role of endothelin A and B receptors in these processes, we have studied the effect of a complex spectrum of endothelin receptor ligands on intracellular calcium concentration changes in proliferating and differentiated C6 rat glioma cells. Cell differentiation was induced by dibutyryl-cAMP and assessed by the glial fibrillar acidic protein content. Intracellular calcium changes were measured in cell suspensions using fluorescent probe Fura-2. The specific endothelin B receptor agonists sarafotoxin S6c and IRL-1620 did not influence the intracellular calcium concentration. However, calcium changes induced by endothelin-1 and especially by endothelin-3 after the pretreatment of cells with one of these endothelin B receptor specific agonists were significantly enhanced even above the values attained by the highest effective endothelin concentrations alone. Such endothelin B-receptor ligand-induced sensitization of calcium signaling was not observed in differentiated C6 cells. Moreover, endothelin-induced calcium oscillations in differentiated C6 cells were less inhibited by BQ-123 and BQ-788 than in their proliferating counterparts. In conclusion, the specific activation of endothelin B receptor in C6 rat glioma cells does not affect intracellular calcium per se, but probably does so through interaction with the endothelin A receptor. The pattern and/or functional parameters of endothelin receptors in C6 rat glioma cells are modified by cell differentiation., R. Malík, K. Vlašicová, A. Šedo., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

74. Ghrelin - a New Endogenous Growth Hormone Secretagogue

Creator:
Martina Rosická, Michal Kršek, Zuzana Jarkovská, Jan Marek, and Richard Češka
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Type:
article, články, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Energy expenditure, Ghrel, Growth hormone secretagogue, Leptin, Ob/Ob Mice, 14, and 612
Language:
English
Description:
Ghrelin is a new endogenous peptide, discovered in 1999 by Kojima et al., as the result of a search for an endogenous ligand for an orphan receptor of known structure and function. Ghrelin is composed of 28 amino acids and is produced mostly by cells of the stomach, hypothalamus, and hypophysis, but it has also been detected in other tissues. Its discovery is related to the development of a new hypothesis regarding the regulation of growth hormone secretion. It is an antagonist of somatostatin. Ghrelin activates the release of growth hormone from the somatotrophic cells of the hypophysis. It participates in the regulation of energy homeostasis, increases food intake, decreases energy output and exerts a lipogenetic effect. Its metabolic effects do not depend on the GH/IGF-I system, but are mediated by the NPY/Y1 and AGRP receptor system. Ghrelin influences the secretion and motility of the gastrointestinal tract, especially the stomach. The presence of ghrelin and its receptors has also been demonstrated in many other tissues. Its function in these tissues has not yet been studied, thus providing many possibilities for further research., M. Rosická, M. Kršek, Z. Jarkovská, J. Marek, V. Schreiber., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

75. Glutamate Induces Different Neuronal Conditioned Responses than ACPD When Used As a Locally Ionophoresed Unconditioned Stimulus in the Cat Motor Cortex

Creator:
Woody, Ch. D.
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article, studie, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Conditioning, Learning, Pavlov, Metabotropic receptors, Excitatory amino acids, 14, and 612
Language:
English
Description:
Single unit recordings were made from the motor cortex of conscious cats with glass micropipettes that allowed ionophoretic application of 0.5 M glutamate in 2 M NaCl or 0.5 M ACPD (1S,3R-1-amino-cyclopentane-1,3-dicarboxylic acid, a mGluR agonist) in 2 M NaCl. Activity in response to a 70 dB click (1 ms rectangular pulse to loudspeaker) was studied before, during, and immediately after applying each agent locally as a paired US (90 nA current 570 ms after click for 300 ms in combination with glabella tap). A 70 dB hiss sound was presented 4.4 sec after the click as a discriminative stimulus (DS). CS and DS were presented 10 times initially (adaptation); then CS, US plus tap, and DS (approximately 10 times as conditioning); and then CS and DS (2-10 times to test post-conditioning). Glutamate potentiated the mean, early, 8-16 ms response to the click after conditioning (t=18.2, p<0.0001), but not the baseline activity which decreased from a mean of 17 spk/sec to 7 spk/sec (t=3.71, p<0.001). Baseline activity increased to 31 spk/sec when glutamate was applied during conditioning (t=3.30, p<0.005). ACPD reduced the intermediate, 64-72 ms response to the click after conditioning (t=8.18, p<0.0001), and potentiated the late 104-112 ms response (t=15.4, p<0.0001). Baseline activity was slightly increased after conditioning with ACPD. Saline did not potentiate the response to click. The results indicate that glutamate agonists that differ in their receptor affinities can induce different CRs when used as locally applied USs to condition neuronal responses to a click CS in the motor cortex of cats., Ch. D. Woody., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

76. Heat stress prevents the decrease in succinate dehydrogenase activity in the extensor digitorum longus of streptozotocin-induced diabetic rats

Creator:
Nonaka, K, Une, S, Akiyama, J, Yamaji, R, and Komatsu, M
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Type:
model:article and TEXT
Subject:
fyziologie člověka, human physiology, Diabetes mellitus, Heat stress, Succinate dehydrogenase, Heat shock protein 60, Superoxide dismutase 2, 14, and 612
Language:
English
Description:
This study aimed to investigate whether heat stress (HS) prevents a decrease in succinate dehydrogenase (SDH) activity and heat shock protein 60 (HSP60) and superoxide dismutase 2 (SOD2) contents in the extensor digitorum longus of streptozotocin (STZ)-induced diabetic rats. Twelve-week-old male Wistar rats were assigned to one of the four groups (n=6/group): control (Con), HS, diabetes mellitus (DM), and diabetes mellitus and heat stress (DM+HS). Diabetes was induced by the administration of STZ (50 mg/kg). HS was initiated 7 days after STZ treatment and performed at 42 °C for 30 min 5 times a week for 3 weeks. SDH activity was decreased in the DM and DM+HS groups. However, SDH activity was greater in the DM+HS group than in the DM group. Although HSP60 content was lower in the DM group than in the Con group, it was maintained in the DM+HS groups and was higher than that in the DM group. SOD2 content was decreased only in the DM group. These findings suggest that HS prevents the decrease in SDH activity in the skeletal muscle induced by DM. According to this mechanism, the maintenance of SOD2 and HSP60 by HS may suppress the increase in oxidative stress., K. Nonaka, S. Une, M. Komatsu, R. Yamaji, J. Akiyama., and Seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

77. Hematopoiesis-Stimulating and Anti-Tumor Effects of Repeated Administration of Diclofenac in Mice with Transplanted Fibrosarcoma Cells

Creator:
Hofer, M., Zuzana Hoferová, Peter Fedoročko, and Naděžda O. Macková
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Type:
article, studie, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Diclofenac, Prostaglandins, Hematopoiesis, Fibrosarcoma, 14, and 612
Language:
English
Description:
Positive effects of repeated administration of diclofenac, an inhibitor of prostaglandin synthesis, in terms of prevention of tumor development and stimulation of hematopoiesis have been observed in C3H mice transplanted subcutaneously with G:5:113 fibrosarcoma cells. Fourteen-day treatment with diclofenac (3.75 mg/kg/day) started from day 5 after tumor cell transplantation. Measurements of tumors and hematological examinations were performed on day 30. The results strongly suggest the possibility that inhibitors of prostaglandin synthesis (non-steroidal anti-inflammatory drugs) may be used in oncological practice where the observed effects are highly desirable., M. Hofer, Z. Hoferová, P. Fedoročko, N. O. Macková., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

78. Hippocampus-Dependent Retrieval and Hippocampus-Independent Extinction of Place Avoidance Navigation, and Stress-Induced Out-of-Context Activation of a Memory Revealed by Reversible Lesion Experiments in Rats

Creator:
Karel Ježek, Wesierska, M., and Fenton, A. A.
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Type:
article, studie, model:article, and TEXT
Subject:
Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, 14, and 612
Language:
English
Description:
The use of reversible lesion techniques in memory research was pioneered in the laboratory of Jan Bureš and Olga Burešova. We use the occasion of Jan’s 75th birthday to briefly review the experimental utility of this approach. Two experiments from our current research are reported in which reversible lesioning methods are used to ask otherwise experimentally untenable questions about memory retrieval. The first experiment used intra-hippocampal injections of tetrodotoxin to temporarily inactivate the hippocampus during retrieval of a well-learned place avoidance navigation memory. This revealed that the hippocampus is necessary for place avoidance retrieval but that the extinction of place avoidance can occur independently of retrieving the memory and intact hippocampal function. The second experiment used KCl-induced cortical spreading depression in an interhippocampal transfer paradigm to demonstrate that a Y-maze memory that is learned by only one cortical hemisphere can be made to transfer to the other hemisphere by forcing the rat to swim, a unique stressful experience that occurred in a different apparatus, different behavioral context, and involved different behaviors than the Y-maze training. This demonstrates, we believe for the first time behaviorally, that memories can be activated outside of the behavioral context of their acquisition and expression in rats., K. Ježek, M. Wesierska, A. A. Fenton., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

79. Histidine metabolism after Bretschneider cardioplegia in cardiac surgical patients

Creator:
Teloh, J. K, Ansorge, L, Dohle, D.-S, Jakob, H, Brauckmann, S, Waack, I. N, Demircioglu, E, and Petersen, M
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Type:
model:article and TEXT
Subject:
fyziologie člověka, human physiology, Urine, Catecholamines, N-methylimidazole acetic acid, Catabolism, 14, and 612
Language:
English
Description:
Bretschneider (histidine-tryptophan-ketoglutarate) solution with its high histidine concentration (198 mM) is one of many cardioplegic solutions, which are routinely used for cardiac arrest. The aim of this study was to evaluate the physiological biochemical degradation of administered histidine to histamine and its major urinary metabolite N-methylimidazole acetic acid. A total number of thirteen consecutive patients scheduled for elective isolated coronary artery bypass grafting with cardiopulmonary bypass were enrolled in the prospective observational designed study at the Department of Thoracic and Cardiovascular Surgery between 04/2016 and 06/2016. Patients received 1.7 l Bretschneider solution on average. Before and at the end of operation as well as in the postoperative course, urine samples gathered from the urinary catheter bag were analyzed. During the operative period, urinary histidine concentration significantly increased from 29 μmol/mmol creatinine to 9,609 μmol/mmol creatinine. Postoperatively, histidine excretion reduced while histamine as well as N-methylimidazole acetic acid excretion rose significantly. Patients showed elevated levels of histidine, histamine as well as N-methylimidazole acetic acid in urine, but no unmanageable hemodynamic instability possibly arising from the histamine’s biological properties. Chemically modified histidine might reduce uptake and metabolization while maintaining the advantages of buffer capacity., J. K. Teloh, L. Ansorge, M. Petersen, E. Demircioglu, I. N. Waack, S. Brauckmann, H. Jakob, D.-S. Dohle., and Seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

80. How to interpret elevated plasmatic level of high-sensitive troponin T in newborns and infants?

Creator:
Petr Jehlička, Michal Huml, Masopustová, A, Jiří Dort, Matas, M, Alice Mocková, and Daniel Rajdl
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Type:
model:article and TEXT
Subject:
fyziologie člověka, human physiology, High sensitive troponin T, Infants, Myocardial damage, Newborns, 14, and 612
Language:
English
Description:
Research and clinical implications on novel cardiac biomarkers has intensified significantly in the past few years. The highsensitive troponin T (hscTnT) assay plays a dominant role in diagnostic algorithm regarding myocardial injury in adults. Despite generally accepted use of hscTnT there are no data about physiological concentrations and cut-off limits in neonates and infants to date. The aim of this study is to assess hscTnT levels in healthy newborns and infants. Consecutively 454 healthy full termed newborns and 40 healthy infants were enrolled in the study. Samples of cord or venous blood were drawn and tested for hscTnT concentrations with high-sensitive TnT assay (Roche Cobas e602 immunochemical analyzer). The 97.5 percentile of hscTnT concentration was assessed and correlation analysis was performed in neonates. Two hundred and thirteen samples (47 %) were excluded due to blood hemolysis of various degrees in neonates. Finally, the group of 241 healthy newborns was statistically analyzed. The median concentration of hscTnT was 38.2 ng/ml, 97.5 percentile reached 83.0 ng/l (confidential interval 74.1 to 106.9 ng/l). HscTnT concentrations were statistically decreased in hemolytic samples when compared to non-hemolytic samples (34.3 ng/l [26.7 to 42.0 ng/l] and 37.1 ng/l [30.5 to 47.9 ng/l], respectively, p=0.003). Elevated plasma concentrations of hscTnT decreased to adult level within six months. This study has confirmed the higher reference levels of hscTnT in neonates and young infants when compared with adult population. Many extracardiac factors as hemolysis and age may affect the hscTnT level. Based on presented results, a careful clinical interpretation of hscTnT is recommended., P. Jehlička, M. Huml, D. Rajdl, A. Mocková, M. Matas, J. Dort, A. Masopustová., and Seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public