Search results for "Bicarbonates"
showing 10 items of 20 documents
Spatial and temporal dynamics of bacterioplankton community composition in a subtropical dammed karst river of southwestern China.
2018
Abstract River damming influences the hydro‐physicochemical variations in karst water; however, such disruption in bacterioplankton communities has seldom been studied. Here, three sampling sites (city‐river section, reservoir area, and outflow area) of the Ca2+–Mg2+–HCO 3 −–SO 4 2− water type in the dammed Liu River were selected to investigate the bacterioplankton community composition as identified by high‐throughput 16S rRNA gene sequencing. In the dammed Liu River, thermal regimes have been altered, which has resulted in considerable spatial‐temporal differences in total dissolved solids (TDSs), oxidation‐reduction potential (Eh), dissolved oxygen (DO), and pH and in a different microe…
Nitric oxide: Relation to integrity, injury, and healing of the gastric mucosa
2001
Nitric oxide (NO) plays a multifaceted role in mucosal integrity. The numerous functions of NO and the double-edged role played by NO in most of them provide a great complexity to the NO action. The three enzymatic sources of NO, neuronal NO-synthase (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS), have been characterised in the gastrointestinal tract. The protective properties of the NO derived from constitutive NO-synthases (eNOS and nNOS) have already been well established. Less clear is the role assigned to iNOS. The simplistic initial view of low levels of NO synthesised by constitutive NOS being protective while exaggerated NO levels after iNOS induction leading irremediably …
Interaction of dicaffeoylquinic derivatives with peroxynitrite and other reactive nitrogen species.
2008
Plant phenolic antioxidants, among them catechins and hydroxycinnamoyl conjugates, constitute a well defined class of inhibitors of reactive nitrogen species (RNS). To gain deeper insight in this field, we examined the effects of 3,5-di-O-caffeoylquinic acid (DCA), its methyl ester (DCE) and epigallocatechin gallate (EGCG) in nitrative and oxidative processes. These compounds were found to be strong inhibitors of the nitration of tyrosine residues induced by ONOO- in bovine seroalbumin, with their IC50 values (10-40 microM) notably decreasing in the presence of bicarbonate. When studied on the intracellular protein tyrosine nitration induced by ONOO- in cultured murine fibroblasts as well a…
The importance of potassium citrate and potassium bicarbonate in the treatment of uric acid renal stones
2017
Uric acid calculi can also be treated without surgery, with simple medical lytic therapy. After appropriate dietary adjustments and add of mineral water, the needed amount of alkali supplementation can increase pH values of the urine in order to dissolve the stones. Treatment should be prolonged to prevent stone recurrence. A case of bilateral renal uric acid stones that were successfully treated by alakalizing treatment was presented.
Mechanistic analysis and experimental verification of bicarbonate-controlled enteric coat dissolution: Potential in vivo implications
2019
Enteric coatings have shown in vivo dissolution rates that are poorly predicted by traditional in vitro tests, with the in vivo dissolution being considerably slower than in vitro. To provide a more mechanistic understanding of this, the dependence of the release properties of various enteric-coated (EC) products on bulk pH and bicarbonate molarity was investigated. It was found that, at presumably in vivo-relevant values, the bicarbonate molarity is a more significant determinant of the dissolution profile than the bulk pH. The findings also indicate that this steep relationship between the dissolution of enteric coatings and bicarbonate molarity limits those coatings' performance in vivo.…
Mechanisms of endothelial cell swelling from lactacidosis studied in vitro
2000
One of the early sequelae of ischemia is an increase of circulating lactic acid that occurs in response to anaerobic metabolism. The purpose of the present study was to investigate whether lactic acidosis can induce endothelial swelling in vitro under closely controlled extracellular conditions. Cell volume of suspended cultured bovine aortic endothelial cells was measured by use of an advanced Coulter technique employing the “pulse area analysis” signal-processing technique (CASY1). The isosmotic reduction of pH from 7.4 to 6.8 had no effect on cell volume. Lowering of pH to 6.6, 6.4, or 6.0, however, led to significant, pH-dependent increases of cell volume. Swelling was more pronounced …
Isolated in-vitro perfusion of pig hearts obtained from the abattoir: an alternative to animal experiments?
1994
Isolated pig hearts (German farm pigs) were characterized after global in-vivo ischaemia as a potential alternative to in-vivo animal studies. Hearts were harvested from adult farm swine at the abattoir 10.3 +/- 2.1 min after incision of the carotid artery. They were immediately perfused and thereafter stored in ice-cold cardioplegic (St Thomas's) solution. After 38 +/- 3 min, retrograde perfusion was started with oxygenated pig blood (37 degrees C; 5000 U Heparin.l-1; pH 7.38 +/- 0.1; 11 mmol glucose.l-1) at a flow rate of 85 ml.min-1 100 g-1 wet weight (gww-1) for 30 min (n = 10). Additionally, shortly after obtaining the hearts, ATP and CP content were measured by enzymatic tests in 10 p…
Topiramate and Metabolic Acidosis in Infants and Toddlers
2002
Summary: Purpose: Topiramate (TPM) inhibits carbonic anhydrase, with metabolic acidosis as a possible side effect, although this has been reported in only two adult cases. We investigated the acid–base metabolism in infants and toddlers treated with TPM. Methods: Nine infants and toddlers aged 5 months to 2.3 years (median, 6 months) were treated with TPM at maximal doses of 8.2–26 mg/kg/day (median, 11 mg/kg/day). The maximal TPM dose was achieved after 8–35 days (median, 17 days). TPM was given in addition to other antiepileptic drugs (AEDs) in five cases and as a sole AED in four patients with refractory epilepsy resistant to multiple AEDs. The diagnoses were infantile spasms (n = 5), e…
Prediction of dilutional acidosis based on the revised classical dilution concept for bicarbonate
2004
Due to the controversy surrounding the term dilutional acidosis, the classical dilution concept for bicarbonate has been rigorously revised for the prediction of pH, actual bicarbonate concentration, and base excess. In the algorithms derived for buffer solutions, blood, and whole body (1-, 2-, and 3-fluid compartment), only bicarbonate is considered. On dilution at constant Pco2, the final concentration of bicarbonate is the sum in terms of pH, due to the following processes: dilution, formation from chemical reaction with the nonbicarbonate buffers phosphate, hemoglobin, and plasma proteins, and transfer from erythrocytes and interstitial fluid to plasma. At constant Pco2, the level of c…
The accuracy of calculated base excess in blood.
2002
Most equations used for calculation of the base excess (BE, mmol/l) in human blood are based on the fundamental equation derived by Siggaard-Andersen and called the Van Slyke equation: BE = Z x [[cHCO3-(P) - C7.4 HCO3-(P)] + beta x (pH -7.4)]. In simple approximation, where Z is a constant which depends only on total hemoglobin concentration (cHb, g/dl) in blood, three equations were tested: the ones proposed by Siggaard-Andersen (SA), the National Committee for Clinical Laboratory Standards (NCCLS) or Zander (ZA). They differ only slightly in the solubility factor for carbon dioxide (alphaCO2, mmol/l x mmHg) and in the apparent pK(pK'), but more significantly in the plasma bicarbonate conc…