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1.
[The effect of low dose ionizing radiation exposure on dynamic thiol-disulfide homeostasis and ischemia modified albumin levels: an observational study].
Arıcan, S, Dertli, R, Baktik, S, Hacibeyoglu, G, Erol, A, Ulukaya, SO, Goger, E, Erel, Ö
Brazilian journal of anesthesiology (Elsevier). 2020;(3):233-239
Abstract
BACKGROUND The primary objective of this study was to investigate the effect of low dose ionizing radiation exposure on thiol/disulfide homeostasis and ischemia modified albumin levels. The secondary objective is to compare thiol/disulfide homeostasis and ischemia modified albumin levels among the personnel exposed to low dose ionizing radiation in anesthesia application areas, in and out of the operation room. METHODS The study included a total of 90 volunteers aged between 18 and 65 years old, with 45 personnel working in a setting with potential for radiation exposure (Exposed Group) and 45 personnel in a setting without radiation exposure (Control Group). Their native thiol, total thiol, disulphide, albumine and IMA levels were measured. Exposed group included personnel who were exposed to radiation outside the operating room – Operation room (−) Group and inside the operating room – Operation room (+) Group. RESULTS Albumin, native and total thiol levels were significantly lower in the participants exposed to radiation in the anesthesia application area; no statistically significant difference was found in terms of disulfide and ischemia modified albumin levels. In the Operation room (−) Group exposed to radiation, native thiol and total thiol values were significantly lower compared to the Operation room (+) Group. CONCLUSION Awareness of being in danger of oxidative stress should be established in personnel exposed to radiation in the anesthesia application area following low dose ionizing radiation exposure, and the necessary measures should be taken.
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2.
The 808 nm and 980 nm infrared laser irradiation affects spore germination and stored calcium homeostasis: A comparative study using delivery hand-pieces with standard (Gaussian) or flat-top profile.
Ferrando, S, Agas, D, Mirata, S, Signore, A, De Angelis, N, Ravera, S, Utyuzh, AS, Parker, S, Sabbieti, MG, Benedicenti, S, et al
Journal of photochemistry and photobiology. B, Biology. 2019;:111627
Abstract
Photobiomodulation relies on the transfer of energy from incident photons to a cell photoacceptor. For many years the concept of photobiomodulation and its outcome has been based upon a belief that the sole receptor within the cell was the mitochondrion. Recently, it has become apparent that there are other photoacceptors operating in different regions of the electromagnetic spectrum. Alternative photoacceptors would appear to be water and mechanisms regulating calcium homeostasis, despite a direct effect of laser photonic energy on intracellular calcium concentration outwith mitochondrial activity or influence, have not been clearly demonstrated. Therefore, to increase the knowledge of intracellular‑calcium and laser photon interaction, as well as to demonstrate differences in irradiation profiles with modern hand-pieces, we tested and compared the photobiomodulatory effect of 808 nm and 980 nm diode laser light by low- and higher-energy (60s, 100 mW/cm2, 100 mW/cm2, 500 mW/cm2, 1000 mW/cm2, 1500 mW/cm2, 2000 mW/cm2) irradiated with a "standard" (Gaussian fluence distribution) hand-piece or with a "flat-top" (uniform fluence) hand-piece. For this purpose, we used the eukaryote unicellular-model Dictyostelium discoideum. The 808 nm and 980 nm infrared laser light, at the energy tested directly affect the stored Ca2+ homeostasis, independent of the mitochondrial respiratory chain activities. From an organism perspective, the effect on Ca2+-dependent signal transduction as the regulator of spore germination in Dictyostelium, demonstrates how a cell can respond quickly to the correct laser photonic stimulus through a different cellular pathway than the known light-chromophore(mitochondria) interaction. Additionally, both hand-piece designs tested were able to photobiomodulate the D. discoideum cell; however, the hand-piece with a flat-top profile, through uniform fluence levels allows more effective and reproducible effects.
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3.
Evolution of pH buffers and water homeostasis in eukaryotes: homology between humans and Acanthamoeba proteins.
Baig, AM, Zohaib, R, Tariq, S, Ahmad, HR
Future microbiology. 2018;:195-207
Abstract
AIM: This study intended to trace the evolution of acid-base buffers and water homeostasis in eukaryotes. Acanthamoeba castellanii was selected as a model unicellular eukaryote for this purpose. Homologies of proteins involved in pH and water regulatory mechanisms at cellular levels were compared between humans and A. castellanii. MATERIALS & METHODS Amino acid sequence homology, structural homology, 3D modeling and docking prediction were done to show the extent of similarities between carbonic anhydrase 1 (CA1), aquaporin (AQP), band-3 protein and H+ pump. Experimental assays were done with acetazolamide (AZM), brinzolamide and mannitol to observe their effects on the trophozoites of A. castellanii. RESULTS The human CA1, AQP, band-3 protein and H+-transport proteins revealed similar proteins in Acanthamoeba. Docking showed the binding of AZM on amoebal AQP-like proteins. Acanthamoeba showed transient shape changes and encystation at differential doses of brinzolamide, mannitol and AZM. Conclusion: Water and pH regulating adapter proteins in Acanthamoeba and humans show significant homology, these mechanisms evolved early in the primitive unicellular eukaryotes and have remained conserved in multicellular eukaryotes.
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4.
Vascular endothelial growth factor C levels are modulated by dietary salt intake in proteinuric chronic kidney disease patients and in healthy subjects.
Slagman, MC, Kwakernaak, AJ, Yazdani, S, Laverman, GD, van den Born, J, Titze, J, Navis, G
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2012;(3):978-82
Abstract
BACKGROUND Recent experimental findings demonstrate vascular endothelial growth factor C (VEGF-C)-mediated water-free storage of salt in the interstitium, which prevents a salt-sensitive blood pressure state. It is unknown whether this mechanism plays a role in salt homeostasis and regulation of blood pressure in humans as well. Therefore, we investigated circulating VEGF-C levels and blood pressure during different well-controlled salt intake in chronic kidney disease (CKD) patients and in healthy subjects. METHODS In two crossover studies, non-diabetic proteinuric CKD patients (n = 32) and healthy subjects (n = 31) were treated with consecutively a low-sodium diet (LS, aim 50 mmol Na(+)/day) and a high-sodium diet (HS, aim 200 mmol Na(+)/day) in random order, during two 6-week (CKD patients) and two 1-week periods (healthy subjects). RESULTS We found that VEGF-C levels are higher during HS than during LS in CKD patients (P = 0.034) with a trend towards higher VEGF-C in healthy subjects as well (P = 0.070). In CKD patients, HS was associated with higher NT-proBNP levels (P = 0.005) and body weight (P = 0.013), consistent with extracellular volume (ECV) expansion and with higher blood pressure (P < 0.001), indicating salt sensitivity. In healthy subjects, blood pressure was not affected by dietary salt (P = 0.14), despite a rise in ECV (P = 0.023). DISCUSSION Our findings support a role for VEGF-C-mediated salt homeostasis in humans. Considering the salt sensitivity of blood pressure, this buffering mechanism appears to be insufficient in proteinuric CKD patients. Future studies are needed to provide causality and to substantiate the clinical and therapeutic relevance of this VEGF-C regulatory mechanism in humans.
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5.
[The influence of antihypertensive agents on plasmatic and vascular-thrombocytic homeostasis in metabolic syndrome].
Vengerovskiĭ, AI, Idrisova, EM, Bushkova, EA, Mananko, EI, Krasnova, NM
Eksperimental'naia i klinicheskaia farmakologiia. 2008;(6):8-12
Abstract
The combined therapy with enalapril and prolonged-release verapamil, as well as with enalapril and moxonidine significantly increases the level of antiatherogenic high-density-lipoprotein cholesterol, reduces the atherogenicity coefficients, decreases the concentrations of glucose, glycosylated hemoglobin, and soluble fibrinmonomeric complexes and the aggregation activity of thrombocytes, activates plasminogen in the blood of patients under conditions of metabolic syndrome with arterial hypertension. At the same time the enalapril monotherapy has no significant influence on the parameters of lipid and carbohydrate metabolism and the plasmatic and vascular-thrombocytic homeostasis.
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6.
[Brain glucose sensing].
Pénicaud, L, Fioramonti, X, Lorsignol, A, Bénani, A, Leloup, C
Bulletin de l'Academie nationale de medecine. 2007;(4-5):923-31; discussion 932
Abstract
Brain nutrient sensing permits fine regulation of physiological functions such as food intake and blood glucose regulation related to energy homeostasis. The mechanism of glucose sensing is the most extensively studied, and parallels have been drawn between pancreatic beta cells and neurons. Two types of glucose-sensing neuron have been identified, namely those whose activity is directly proportional to the glucose concentration, and those whose activity is inversely proportional to the glucose concentration. It was recently demonstrated that the mechanism depends on the amplitude of change in the glucose concentration. In some cases detection is probably not ensured by neurons themselves but by astrocytes, indicating that the two cell types are coupled in some way. Glucose sensing can be modulated by other nutrients (particularly fatty acids) and also by hormones (insulin, leptin and ghrelin) and peptides (NPY). The subtle cellular and molecular mechanisms involved in glucose sensing probably explain reported discrepancies in the expression of glucose transporters, hexokinases and channels. Astrocytes might also be involved in one type of response, thus adding a new level of complexity.
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7.
Comparative effects of oral aromatic and branched-chain amino acids on urine calcium excretion in humans.
Dawson-Hughes, B, Harris, SS, Rasmussen, HM, Dallal, GE
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2007;(7):955-61
Abstract
UNLABELLED In 30 adults, increasing intake of aromatic amino acids increased calcium excretion and serum IGF-1, but not indices of bone turnover, when compared with similar increases in intake of branched-chain amino acids. The mechanisms involved are not certain but these findings suggest a role for the calcium sensor receptor. INTRODUCTION In contrast to branched-chain amino acids (BCAAs), aromatic amino acids (AAAs) bind to the calcium sensing receptor (CaR) and thus have an increased potential to affect calcium homeostasis. In this study we compare the effects of increased intake of AAAs versus BCAAs on calcium excretion, serum IGF-1, markers of bone turnover, and 4-hr calcium excretion after an oral calcium load. METHODS After two weeks on low-protein metabolic diets, 30 healthy subjects were randomized to a fivefold increase in intake of AAAs or BCAAs for two weeks. Changes in calcium excretion and other measures were compared in the two groups. RESULTS With the increase in amino acid intake, 24-hr calcium excretion (P = 0.027), IGF-1 (P = 0.022), and 4-hr calcium excretion after an oral load (P = 0.023) increased significantly in the AAA relative to the BCAA group. Group changes in turnover markers did not differ significantly. CONCLUSION In comparison with BCAAs, AAAs promoted calcium excretion. The calciuria does not appear to result from increases in bone resorption and may occur by increasing calcium absorption. The AAAs also increased circulating levels of IGF-1. Collectively these findings raise the possibility that AAAs may selectively influence calcium homeostasis through their interactions with the CaR.
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8.
What serum calcium can tell us and what it can't.
Houillier, P, Froissart, M, Maruani, G, Blanchard, A
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. 2006;(1):29-32
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9.
[Homeostasis and magnesium--comparison with calcium].
Fujita, T
Clinical calcium. 2005;(11):23-8
Abstract
Although Mg and Ca, bivalent cations commonly coexisting in nature and living organism, share some similar chemical properties, the role played by Mg in biological regulation and signal transduction is far less important than that by Ca. In contrast to the vast extra- and intra-cellular concentration gradient of Ca as high as 10,000, intracellular Mg is only 3 times as high as extracellular Mg. Systemic Mg metabolism including serum Mg only controlled by renal tubular reabsorption is not as precisely regulated as the Ca counterpart most precisely controlled by parathyroid hormone (PTH), 1,25 (OH)(2) vitamin D and bone. Such difference between Mg and Ca is probably based on the properties of these two kinds of atoms. Mg has a smaller ionic radius with electron arrangement making protein binding more difficult and velocity constant for water binding smaller. Signal transduction by Mg is thus destined to be much less efficient than that by Ca.
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10.
Modeling stability of photoheterotrophic continuous cultures in photobioreactors.
Cornet, JF, Favier, L, Dussap, CG
Biotechnology progress. 2003;(4):1216-27
Abstract
Continuous cultures of the purple non-sulfur bacterium Rhodospirillum rubrum were grown in a cylindrical photobioreactor in photoheterotrophic conditions, using acetate as carbon source. A new kinetic and stoichiometric knowledge model was developed, and its ability to simulate experimental results obtained under varying incident light fluxes and residence times is discussed. The model accurately predicts the stable, unstable, or oscillating behavior observed for the reactor productivity. In particular, the values of residence time corresponding to a subcritical bifurcation with a typical hysteresis effect are calculated and analyzed. The robustness of the proposed model allows the engineering operating domain of the photobioreactor function to be set and offers a promising tool for the design and control of such photoheterotrophic processes.