Acid Pool Research Articles

Changes in vineyard soil parameters after repeated application of organic-inorganic amendments based on spent mushroom substrate

The changes of physicochemical and biochemical parameters of a silty loam (S1) and sandy loam (S2) vineyard soils added with spent mushroom substrate (SMS) or SMS composted with ophite (OF) as rock dust (SMS + OF) were studied. Two doses of SMS or SMS + OF (25 and 100 Mg ha−1) were applied for two consecutive years (2020–2021) and changes of soil physicochemical parameters, and dehydrogenase activity (DHA), respiration (RES), microbial biomass (BIO), and the phospholipid fatty acids (PLFAs) profile were assayed on a temporal basis. The results showed an increase in soil organic carbon (OC) content, total and mineralised N, P, and K, especially when the highest SMS dose was applied to soils. Repeated application caused OC content over time up to 2.3 times higher than initial content in the silty loam soil. This increase was not observed in sandy soil, possibly due to a higher bioavailability of OC, as indicated by the evolution of extractable humic acid/fulvic acid pools. In both soils, all biochemical parameters increased after amendment, being favoured both by the OC and by the presence of OF. Significant positive correlations were found between DHA, RES and BIO, and OC content especially in the first part and then levelled off after the second dose application. Total bacterial or fungal PLFAs patterns reflected the variation of BIO by SMS application. The higher growth of fungi vs. bacterial community in amended soils was recorded after the first SMS application, although the opposite effect occurred after the second application, with similar results in both soils. The findings indicate that the application of SMS or SMS + OF in vineyard soils could be an appropriate agronomic management practice for maintaining soil sustainability, although doses and application times of these amendments should first be evaluated depending on soil texture.

Pools of Amino Acids of Skeletal Muscle in Yakutian Ground Squirrel Urocitellus undulatus during Different Hibernation Stages

Pools of Amino Acids of Skeletal Muscle in Yakutian Ground Squirrel Urocitellus undulatus during Different Hibernation Stages

Nutrient-depended metabolic switching during batch cultivation of Streptomyces coelicolor explored with absolute quantitative mass spectrometry-based metabolite profiling

The well-known secondary metabolite-producing bacterium Streptomyces coelicolor is a natural choice for the development of super-hosts optimized for the heterologous expression of antibiotic biosynthetic gene clusters (BGCs). In this study, we used S. coelicolor M145 and its derivative strain M1146 where all active BGCs have been deleted and generated high-resolution quantitative time series metabolite profiles under two cultivation conditions (phosphate and nitrogen limitation to cease growth and trigger secondary metabolism). Five targeted LC–MS/MS-based methods were used to quantify intracellular primary metabolites covering phosphorylated metabolites, amino acids, organic acids, (deoxy) nucleoside/sugar phosphates, Nicotinamide adenine dinucleotide (NAD), and Coenzyme A (CoA). The nitrogen limitation resulted in a sharp decline in respiration and an immediate drop in the cell mass concentration. Intracellularly, a reduction in the level of the metabolites next to α-ketoglutarate in the tricarboxylic acid cycle and a decrease in the NADH pool were among the most prominent adaptation to this nutrient limitation. Phosphate limitation evoked a different adaptation of the metabolite pools as most of the phosphorylated metabolite pools except 6-phosphogluconic acid (6PG) pool were downregulated. 13C-isotope-labeling experiments revealed the simultaneous activity of both glycolysis and gluconeogenesis during the co-utilization of glucose and glutamate. The S. coelicolor M1146 strain had similar time-series metabolite profile dynamics as the parent M145 strain, except for a visibly increased 6PG pool in the stationary phase. In general, the nutrient limitation had a larger effect on the metabolite pool levels than the absence of secondary metabolite production in M1146. This study provides new insight into the primary carbon metabolism and its link to the secondary metabolism which is needed for further optimization of both super-host genotype and cultivation conditions.

Chlorogenic Acid Inhibits Lipid Deposition by Regulating the Enterohepatic FXR-FGF15 Pathway

Aim Chlorogenic acid (CGA) is a natural polyphenolic compound found in human dietary products. Previous studies have confirmed that CGA has many biological activities, such as regulating glucose and lipid metabolism and improving insulin resistance. However, its underlying mechanisms of action remains unclear. Here, we demonstrate the protective effects and molecular mechanisms of action of CGA in reducing weight gain and hyperlipidemia in mice fed with a high-fat diet (HFD). Methods and Results C57BL/6 mice were fed with normal chow or HFD; half of the mice in each group received CGA treatment by oral gavage for 16 weeks. CGA treatment was found to significantly inhibit HFD-induced weight gain and hyperlipidemia and increased energy expenditure by promoting the expression of genes involved in thermogenesis and mitochondrial biogenesis. Furthermore, CGA was shown to inhibit the enterohepatic farnesoid X receptor (FXR) fibroblast growth factor 15 (FGF15) pathway and changes serum bile acid (BA) pool, thereby contributing to the increased expression of cholesterol 7 α-hydroxylase (CYP7A1). Conclusions CGA increases the metabolic elimination of cholesterol by inhibiting the enterohepatic FXR/FGF15 pathway.

Анаплеротичні принципи нутритивної терапії в клініці критичних станів

У статті надані сучасні анаплеротичні концепції нутритивної терапії для модуляції метаболічної відповіді в клініці критичних станів. Метаболічний стрес — універсальна гіперметаболічна гіперкатаболічна відповідь на захворювання, травму з активацією гіпоталамо-гіпофізарно-адреналової системи; виділенням гормонів стресу; катехоламінів; нейропептиду S; фактора, індукованого гіпоксією HIF-1α; експресією генів, що контролюють механізми адаптації до гіпоксії, у тому числі гліколіз і цикл трикарбонових кислот. У статті наведена розроблена нами модель визначення метаболічного стресу і мітохондріальної дисфункції. Анаплеротична терапія базується на концепції використання альтернативних субстратів як для циклу трикарбонових кислот, так і для транспорту електронів у дихальному ланцюзі з метою посилення продукції аденозинтрифосфату. Багато патологічних станів вимагають проведення анаплеротичної терапії або шляхом поповнення пулу анаплеротичних субстратів (піруват, аспартат, аспарагінат та інші джерела, поповнюючи оксалоацетат, глутамін та інші кислоти), або видаленням з тканин продуктів катаплеротичних реакцій — інтермедіатів циклу трикарбонових кислот. Катаплероз врівноважує анаплероз шляхом переміщення надлишку інтермедіаторів циклу трикарбонових кислот з мітохондріального матриксу в цитоплазму, в екстрамітохондріальний простір. Сучасні анаплеротичні концепції для модуляції метаболічної відповіді при критичних станах включають в себе такі позиції: I. Раннє використання розчинів глюкози та інтенсивна інсулінотерапія: мінімальна кількість вуглеводів близько 2 г/кг глюкози/добу; введення інсуліну, якщо два послідовних аналізи показали рівень глюкози > 10 ммоль/л; уникати обов’язкового повноцінного калорійного харчування в перший тиждень, починати з 500 ккал/добу. II. Попередження гіперглікемічного метаболічного стресу — метаболічне прекондиціювання: вживання прозорих рідин припиняється за 2 години до індукції в анестезію, споживання щільної їжі — за 6 годин. Передопераційне призначення вуглеводів застосовується у всіх пацієнтів без цукрового діабету за 2 години до індукції; при наявності протипоказань — в/в інфузія глюкози за 2 години до операції. III. Використання енергосубстратів, що не потребують інсулінової стимуляції для їх входження до клітини: виявлено, що особи, які одержували < 60 г фруктози на добу, мали кращі показники здоров’я, ніж ті, які споживали > 100 г/добу. IV. Амінокислотні суміші: якщо парентеральне харчування показано, доцільно призначати збалансовані амінокислотні суміші, з розрахунку 1,3–1,5 г/кг/добу білка; 0,2–0,4 г/кг/добу L-глутаміну. При тяжких опіках режим введення білка в амінокислотних сумішах зростає до 1,5–2 г/кг/добу. V. Поповнення пулу анаплеротичних жирних кислот: жирові емульсії (LCT, MCT) повинні призначатися в кількості 0,7–1,5 г/кг/добу; ентерально призначається суміш соєвої і оливкової олій, риб’ячий жир, що містять омега-3, -6, -9 жирні кислоти; дієтична анаплеротична терапія з тригептаноїном підвищує виживаність пацієнтів у критичних станах. VI. Використання інтермедіатів циклу Кребса: превентивне або терапевтичне використання сукцинатвмісних препаратів може бути ефективним для активації ургентних адаптивних механізмів. Тіамін є найважливішим вітаміном для підтримки аеробного метаболізму й активності ключових ферментів циклу Кребса, а також чолночного механізму пентозофосфатного циклу.

Bile salt hydrolase profiling by fluorogenic probes in the human gut microbiome.

Bile is a digestive fluid produced in the liver and stored in the gallbladder. It participates in absorption of fatty nutrients and vitamins, and aids in elimination of metabolic waste and toxins. The major chemical components of bile are bile salts that, apart from their function in digestion, are also known to participate in cell signaling by binding host farnesoid X (FXR), vitamin D (VDR), and G-protein coupled bile acid (TGR5) receptors. Microbial bile salt hydrolases (BSHs) catalyze bile salt deconjugation, a gatekeeper reaction that is a prerequisite for all subsequent microbial transformations of bile acids. As a result, BSH determines the composition of the bile salt and acid pools, which in turn affects its nutrient absorption and signaling capabilities. BSH profiling remains a challenge due to a paucity of tools that enable scientists to study its function. In this chapter, we discuss current BSH profiling approaches and demonstrate a novel fluorogenic probe-based assay that circumvents laborious and resource intensive BSH quantification methods. Alongside our assay protocol, we provide the reader with a detailed method for microbial cell extraction from fecal matter. We also cover probe validation protocols that can be adapted for Michaelis-Menten analysis with any BSH expressing strain.

A higher bacterial inward BCAA transport driven by Faecalibacterium prausnitzii is associated with lower serum levels of BCAA in early adolescents

BackgroundElevations of circulating branched-chain amino acids (BCAA) are observed in humans with obesity and metabolic comorbidities, such as insulin resistance. Although it has been described that microbial metabolism contributes to the circulating pool of these amino acids, studies are still scarce, particularly in pediatric populations. Thus, we aimed to explore whether in early adolescents, gut microbiome was associated to circulating BCAA and in this way to insulin resistance.MethodsShotgun sequencing was performed in DNA from fecal samples of 23 early adolescents (10–12 years old) and amino acid targeted metabolomics analysis was performed by LC–MS/MS in serum samples. By using the HUMAnN2 algorithm we explored microbiome functional profiles to identify whether bacterial metabolism contributed to serum BCAA levels and insulin resistance markers.ResultsWe identified that abundance of genes encoding bacterial BCAA inward transporters were negatively correlated with circulating BCAA and HOMA-IR (P < 0.01). Interestingly, Faecalibacterium prausnitzii contributed to approximately ~ 70% of bacterial BCAA transporters gene count. Moreover, Faecalibacterium prausnitzii abundance was also negatively correlated with circulating BCAA (P = 0.001) and with HOMA-IR (P = 0.018), after adjusting for age, sex and body adiposity. Finally, the association between Faecalibacterium genus and BCAA levels was replicated over an extended data set (N = 124).ConclusionsWe provide evidence that gut bacterial BCAA transport genes, mainly encoded by Faecalibacterium prausnitzii, are associated with lower circulating BCAA and lower insulin resistance. Based on the later, we propose that the relationship between Faecalibacterium prausnitzii and insulin resistance, could be through modulation of BCAA.

Технологии сохранения функции почек у пациентов с хронической болезнью почек и гиперурикемией

Распространенность хронической болезни почек (ХБП) и гиперурикемии глобально возрастает. Неуклонное увеличение количества пациентов с нарушенной функцией почек на фоне сахарного диабета, артериальной гипертензии и увеличения продолжительности жизни в конечном итоге приводит к значительным расходам, связанным с необходимостью использования дорогостоящих методов почечно-заместительной терапии. Основной задачей для врачей является своевременное определение и замедление прогрессирования ХБП, проведение ренопротекции. Гиперурикемия рассматривается как независимый фактор риска возникновения и прогрессирования болезни кроме традиционных на сегодняшний день микроальбуминурии и снижения скорости клубочковой фильтрации. Актуальность выявления гиперурикемии обусловлена возможностью ее дальнейшей коррекции для улучшения прогноза заболевания и отсрочки конечной стадии ХБП, повышения качества жизни и уменьшения затрат на лечение пациентов. Уменьшение общего пула мочевой кислоты в организме способствует минимизации риска артропатии и нефролитиаза, обострения подагры, прогрессирования почечной недостаточности и других осложнений. Однако, несмотря на сотни опубликованных клинических исследований, посвященных вопросам диагностики и лечения больных с ХБП, качество помощи остается неоптимальным. В статье представлены разносторонние взгляды на технологии сохранения функции почек у пациентов с ХБП и гиперурикемией, требующие усовершенствования.

Interhemispheric Asymmetry in the Pool of Amino Acids during Subtotal Cerebral Ischemia

Interhemispheric Asymmetry in the Pool of Amino Acids during Subtotal Cerebral Ischemia

Molecularly wiring of Cytochrome c with carboxylic acid functionalized hydroquinone on MWCNT surface and its bioelectrocatalytic reduction of H2O2 relevance to biomimetic electron-transport and redox signalling

The electron-transport chain that involves a proton-coupled electron-transfer (ET) reaction between hydroquinone (H2Q) and Cytochrome c (Cyt c) in the acid pool is one of the key processes of the respiratory complex 1 in cytoplasmic membrane of the bacterium and mitochondrial complexes, complex III (cytochrome bc1 or ubiquinol:cytochrome c oxidoreductase) of photosynthesis systems. In the literature, several spectroscopic techniques in association with electron-transfer inhibitors have been reported for this purpose. Till now, there is no straight forward voltammetric proof to reveal the mechanistic feature of the direct ET process. In the electrochemistry point of view, it is a challenging task to prepare a chemically modified bio-electrode composed of H2Q and Cytc redox systems with proper ET channels between them and to probe the mixed-potential reaction by direct voltammetric technique. Herein, we report a carboxylic acid functionalized hydroquinone (2,5-dihydroxy benzoic acid; H2Q-COOH) immobilized multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNT@H2Q-COOH), prepared by in-situ electrochemical oxidation of 2-hydroxy benzoic acid (Ph-COOH), as a molecular wiring system for unfolded Cytc protein and further to study the direct voltammetric ET reaction using H2O2 as a specific probe in pH 2 KCl-HCl medium. The formation of surface-confined H2Q-COOH was confirmed by physicochemical and spectroscopic characterization techniques including IR, Raman, UV-Vis, Thin-layer chromatography, NMR and GC-MS. The GCE/MWCNT@H2Q-COOH showed well-defined redox peaks corresponding to consecutive one-electron-transfer reactions of H2Q-COOH/•QH-COOH (Eo'= 0.410 V vs Ag/AgCl, A1/C1) and •QH-COOH/Q (Eo'= 0.750 V vs Ag/AgCl, A2/C2), similar to one occurs with a membrane-bound ubiquinone and plastoquinone systems in the biological systems. The unfolded Cytc modified electrode, GCE/MWCNT@H2Q-COOH@Cytc prepared by chemical modification technique, has exhibited a specific and selective bioelectrocatalytic reduction current signal in between the redox potentials of QH2/•QH and Cytc in pH 2 KCl-HCl biomimicking the biological electron-transport chain reaction. In further amperometric techniques have been used to successfully demonstrate the ET reaction.

Changes in the concentration of sulfur-containing amino acids in the brain after methionine load in the experimentChanges in the concentration of sulfur-containing amino acids in the brain after methionine load in the experiment

The effect of methionine overload on the state of the pool of sulfur-containing amino acids and their metabolites was studied in the various brain structures determined by reverse phase high performance liquid chromatography (HPLC). In all regions of the brain studied, methionine led to a unidirectional imbalance of sulfur-containing compounds: there was an increase in the concentrations of methionine, cystathionine and hypotaurine. The most pronounced increase in methionine and hypotaurine levels was observed in the striatum, cystathionine in the hemispheres. A significant increase in taurine concentration was observed only in the hypothalamus and striatum. In other parts of the brain a tendency to increase its level was shown. In all brain regions studied except the striatum, serine levels were decreased. In the cerebellum, in comparison with other regions, an increase in the level of cysteic acid and a decrease in the level of cysteinesulfinic acid were observed, which indicates that taurine synthesis is occurred mainly through the cysteine sulfinate oxidation.

Soil Biomarkers as Indicators of Landscape Evolution on the Russian Plain

Biomarkers, due to their structure and biochemistry, are resistant to soil degradation and mineralization under particular environmental conditions, and therefore can provide molecular evidence of paleobiota and past land vegetation, and of the intensity of not only modern, but also past biochemical processes in the biosphere. Parameters of the humus group composition, optical densities of solutions of humic acids, pool of chlorophyll, lipids, fatty acids, and lignin phenols together with the isotopic composition of organic carbon and soil age are suggested as promising biomarkers for paleoecological studies.

Plasma amino acid pools in the umbilical cord artery show lower 15N natural isotope abundance relative to the maternal venous pools

ABSTRACT 15N natural isotope abundance (NIA) is systematically higher in infants’ hair than in that of their mothers at birth. This study aimed to investigate this difference in plasma pools. We compared 15N NIA values for plasma amino acid (AA) pools (free + protein-bound) in the umbilical cord artery (UCA) and vein (UCV) and in the maternal vein (MV) at birth. This preliminary study included 7 mother–infant dyads. Whole plasma was treated (HCl) to hydrolyze protein. Following derivatization, AAs were separated using gas chromatography and compound-specific 15N NIA values were measured on-line using an isotope ratio monitoring mass spectrometer. 15N NIA plasma AA pools in the UCA and UCV were highly correlated to the MV, r 2 > 0.89 and r 2 > 0.88 (both P < 10−4) respectively. The full model found a significant effect of sampling compartment (P = 0.02) and AA type (P < 0.0001) on 15N NIA plasma AA values. 15N NIA plasma AA was 0.74 ‰ higher (P = 0.01) in the MV than in the UCA. This study indicates that a decrease in 15N NIA for plasma AA pools occurs in the fetal–placental unit. Trial registration: ClinicalTrials.gov identifier: NCT00607061.

Nitrogen dynamics after two years of elevated CO2 in phosphorus limited Eucalyptus woodland

It is uncertain how the predicted further rise of atmospheric carbon dioxide (CO2) concentration will affect plant nutrient availability in the future through indirect effects on the gross rates of nitrogen (N) mineralization (production of ammonium) and depolymerization (production of free amino acids) in soil. The response of soil nutrient availability to increasing atmospheric CO2 is particularly important for nutrient poor ecosystems. Within a FACE (Free-Air Carbon dioxide Enrichment) experiment in a native, nutrient poor Eucalyptus woodland (EucFACE) with low soil organic matter (≤ 3%), our results suggested there was no shortage of N. Despite this, microbial N use efficiency was high (c. 90%). The free amino acid (FAA) pool had a fast turnover time (4 h) compared to that of ammonium (NH4+) which was 11 h. Both NH4-N and FAA-N were important N pools; however, protein depolymerization rate was three times faster than gross N mineralization rates, indicating that organic N is directly important in the internal ecosystem N cycle. Hence, the depolymerization was the major provider of plant available N, while the gross N mineralization rate was the constraining factor for inorganic N. After two years of elevated CO2, no major effects on the pools and rates of the soil N cycle were found in spring (November) or at the end of summer (March). The limited response of N pools or N transformation rates to elevated CO2 suggest that N availability was not the limiting factor behind the lack of plant growth response to elevated CO2, previously observed at the site.

Effects of amino acid preparations on the amino acid composition of the liver of rats under subchronic alcohol intoxication

The effects of complex compositions, containing branched-chain amino acids (BCAA), taurine and tryptophan, on the pool of free amino acids in the liver of rats were studied under the conditions of subchronic alcohol intoxication (SHAI). It was established that SHAI led to the decreased levels of treonine, lysine, oxyproline, arginine, b-alanine, as well as the depletion of the pool of irreplaceable amino acids in the liver of rats. Administration of the composition of BCAA and taurine was found to normalize the ratio of replaceable irreplaceable amino acids, the ratio of glycogenic and ketogenic amino acids, to activate the reaction of nitrogen utilization, and to increase Fisher’s index. The effects of the composition, containing BCAA, taurine and tryptophan, were similar to those of amino acid composition that did not contain tryptophan.

1881-P: Separate Free Fatty Acid (FFA) Pools Are Involved in Muscle Lipid Utilization

Despite discrepant phenotypes, the insulin resistant (IR) and trained states have high levels of intramyocellular lipid. We hypothesize that higher muscle lipid turnover in the trained state may explain this discrepancy. Obese, IR subjects and trained subjects were fasted overnight (Table1). To characterize muscle lipid turnover, we conducted a pulse-chase experiment using sequential [U-13C]palmitate and [9-2H]palmitate infusions (6 h each) with a 1 hour overlap to label endogenous and exogenous FFA pools. Biopsy#1 (Bx#1 -s/p 14 hr fast) was performed at the time of the overlap (last hour of the 6 h [U-13C]palmitate infusion, after 1 h of starting the [9-2H]palmitate). Bx#2 was performed at the study conclusion (last hour of the [9-2H]palmitate infusion-s/p 20 hr fast). Plasma and muscle samples were analyzed for palmitate enrichment and concentration. Regardless of phenotype, muscle triglyceride (IMTG) synthesis at Bx#1 was not different as assessed by either [U-13C]palmitate or [9-2H]palmitate; IMTG synthesis assessed by [9-2H]palmitate was 9-fold higher than [U-13C]palmitate. At Bx#2, IMTG breakdown as assessed by [U-13C]palmitate was similar between groups, whereas [9-2H]palmitate showed IMTG synthesis in the obese, IR group and IMTG breakdown in the trained group. IMTG synthesis was higher with recent (1 hour) FFA exposure than more prolonged (6 hour) FFA exposure supporting separate FFA pools in lipid utilization. Disclosure L.S. Chow: None. D.G. Mashek: None. M.D. Jensen: None. Funding National Institutes of Health (R01DK098203, UL1TR000114)

Fully synthetic whole proteins in reach

Peptide Synthesis Solid-phase peptide synthesis of homogeneous peptides longer than about 50 amino acids has been a long-standing challenge because of inefficient coupling and side reactions. Hartrampf et al. used an automated chemistry platform to optimize fast-flow peptide synthesis and were able to produce fully synthetic single-domain proteins (see the Perspective by Proulx). The targets included proinsulin and enzymes such as barnase and a version of HIV-1 protease containing multiple noncanonical amino acids. Refolded peptides were nearly indistinguishable from recombinant proteins, and the synthesized enzymes had activity close to that of their ribosomally synthesized counterparts. This method will enable fast, on-demand synthesis of small proteins with a vastly expanded pool of precursor amino acids. Science , this issue p. [980][1]; see also p. [941][2] [1]: /lookup/doi/10.1126/science.abb2491 [2]: /lookup/doi/10.1126/science.abb9711

Effect of blockade of synthesis of nitric oxide by L-NAME on the level of free amino acids and biogenic amines in the brain cortex of rats with subtotal cerebral ischemia

Mechanisms of development of ischemic stroke are complex and have not been fully established. The aim of this study was to estimate the changes in the pool of free amino acids and biogenic animes in the brain cortex of rats with subtotal cerebral ischemia (SCI) and treated with L-NAME. Experiment was made on 18 rats: 12 animals were undergoing bilateral filament occlusion of arteries carotid, 6 of them were treated with L-NAME. The analyses of free amino acids levels in the blood plasma extracts were carried out by reversed phase HPLC.Concentrations of several amino acids were elevated during SCI including aspartate, b-alanine, valine and leucine. In contrast, the levels of glutamate, asparagine, treonine, gamma-aminobutiric acid, tyrosine and 5-hydroxiindolylacetate were decreased. The administration of L-NAME partially prevented the imbalance of the amino acids pool due to SCI by normalizing the levels of aspartate, glutamate, asparagine, methionine, gamma-aminobutiric acid, b-alanine, 5-hydroxiindolylacetate. However, the administration of L-NAME has induced an additional imbalance in the amino acids pool in the brain cortex (decrease in the levels of glutamine, histidine, taurine, tryptophan, phenylalanine, tyrosine (in comparison to SCI) and decrease in the levels of treonine and arginine. The imbalance of the amino acids pool induced by the administration of L-NAME during SCI is more severe than the imbalance caused by SCI.

24-hour multi-pH recording of the postprandial acid pocket and the nocturnal acid distribution at the esophagogastric junction in healthy volunteers.

Postprandial stationary pH monitoring studies have identified the acid pocket. To what extent a similar pool of acid is present in the fasting state or at night remains however unclear. The study was performed in 9 HV without a hiatal hernia. A pH-impedance-pressure catheter was positioned at the Z-line. First, the presence of the acid pocket was monitored under stationary conditions during 2hours after ingestion of a standardized meal. Thereafter, the equipment was connected to an ambulatory monitoring device for 24-hour recording. Under stationary conditions, a postprandial acid pocket was present in 7 of the 9 HV, from 9±7minutes after meal onwards during 47±8minutes. During ambulatory 24-hour monitoring, postprandial acid pockets emerged significantly later, but no differences in duration or position were detected. During nighttime, an acid pool was detected with its proximal border at the level of the cardia, which at later, time points gradually moved to a more distal position. This led to a gradual decrease in nocturnal acid exposure from proximal to distal, a phenomenon that was preceded by a bust of gastric contractions. Nocturnal reflux originated from the cardiac region, and was more acidic in the early compared with late nocturnal period. The acid pocket is present in the postprandial period under both stationary and ambulatory conditions. Of interest, at night, a pool of acid can be demonstrated which is periodically shifted more distally. This pool of acid represents the reservoir from which nocturnal reflux originates.

Pool of free amino acids in the blood plasma of rats undergoing subtotal cerebral ischemia after L-name administration

A stroke is one of the leading causes of morbidity, disability and mortality in many countries. Mechanisms of development of ischemic stroke are complex and have not been fully established. The aim of this study was to estimate the changes in the pool of free amino acids and their derivatives in the plasma of rats undergoing subtotal cerebral ischemia (SCI) and treated with L-NAME. Experiment was made on 18 rats: 12 animals were undergoing bilateral flament occlusion of arteries carotid, 6 of them were treated with L-NAME. The analyses of free amino acids levels in the blood plasma extracts were carried out by reversedphase HPLC. Concentrations of several amino acids were elevated after 1 hour of ischemia, including aspartate, asparagine, glutamine, glycin, alanine, taurine, phenylalanine, gistidine, 3-methilgistidine, treonine, citrulline, ornitine, as well as branched-chain amino acids. Administration of L-NAME partially prevented the imbalance of the amino acids pool caused by SCI. Preventive injection of L-NAME alleviated the imbalance in the pool of free amino acids of blood plasma caused by SCI.