Carbonate ion-selective electrode with reduced interference from salicylate

Renal tubular acidosis in childhood

The most recent data for the carbon dioxide concentration, alkalinity and partial pressure of carbon dioxide in ocean water are reviewed. The total carbon dioxide content in the oceans is estimated to be 1.39×1020 grams CO2, about 53 times the total atmospheric carbon dioxide content. The oceans contain a greater quantity of CO2 than the amount expected if the oceans were a single homogeneous body of water. This indicates that their capacity is governed by the dynamic processes in the ocean such as the circulation and mixing of ocean water, vertical transpot of carbon by biological processes, and air‐sea CO2 gas exchange. Thus, dynamic models for the carbon cycle in the atmosphere‐ocean system are needed to evaluate the response of the oceanic and atmospheric carbon dioxide reservoirs to the industrial carbon dioxide input and climatic changes. A vertical one‐dimensional and box‐diffusion model, which has been developed by Oeschger et al22, has been used widely and successfully to describe the global carbon cycle. A modified version of their model, in which the size of the land biomass is assumed constant, is presented and used to evaluate the effects of climatic changes on the atmospheric and oceanic reservoirs. It appears that the predicted climatic warming resulting from the industrial carbon dioxide release would cause an increase in the airborne fraction of the industrial carbon dioxide and further accelerate a build‐up of industrial carbon dioxide in the atmosphere. Development of more sophisticated models, which include the ocean circulations, regional differences in the oceans, and climate feedback, is strongly urged for quantitative assessment of the industrial carbon dioxide effects on the climate and the oceanic carbon dioxide reservoir.

A significant discrepancy was noted in our laboratory between the total plasma carbon dioxide concentration measured by the Kodak Ektachem 700 and the bicarbonate concentration derived from the Corning 170 pH/Blood Gas analyser in an 8-day-old patient. The concentration of total carbon dioxide was 18 mmol/L while the derived bicarbonate was 13 mmol/L. The patient was eventually diagnosed as maple syrup urine disease. This finding led us to examine the effect of various organic acids on the measurement of carbon dioxide by the Ektachem 700. Several interfered significantly. Clinicians should be aware that when organic acid concentrations are increased, the Ektachem 700 total carbon dioxide result may be falsely raised.

Six cores were obtained along a 70‐km transect perpendicular to the Peru coast in the highly productive upwelling region near 15°S, at depths ranging from 90 to 5,300 m. All of the sediments sampled were diatomaceous oozes. Three cores overlain by poorly oxygenated water had Thioploca‐like filamentous bacteria in surface sediments. Total organic carbon and total nitrogen contents of the sediments ranged from 0.8 to 10% and from 0.1 to 1% (dry wt). For the 90‐m and 268‐m cores, which had 210Pb surface sediment accumulation rates of about 0.6 and 1.1 cm · yr‒1, surface sediment organic carbon accumulation rates were 40 and 70 g C·m‒2·yr‒1. The organic carbon and total nitrogen distributions in the three cores from the oxygen minimum zone indicate that there have been variations in the rate of accumulation of organic matter over time. These variations may be related in part to the frequency and intensity of El Niño events.Porewater ammonium, nitrate, nitrite, total carbon dioxide, sulfate, and sulfide concentrations were measured. Remineralization rates in sediments calculated from the dissolved carbon dioxide profiles range from 0.6 to 20 g C·m‒2·yr‒1. Total carbon dioxide concentrations in porewaters of two oxygen‐minimum‐zone sediments were modeled using both steady state and nonsteady state distributions of metabolizable organic matter.

The H+ mobilization model has been recently reported to accurately describe intradialytic kinetics of plasma bicarbonate concentration; however, the ability of this model to predict changing bicarbonate kinetics after altering the hemodialysis treatment prescription is unclear. We considered the H+ mobilization model as a pseudo-one-compartment model and showed theoretically that it can be used to determine the acid generation (or production) rate for hemodialysis patients at steady state. It was then demonstrated how changes in predialytic, intradialytic, and immediate postdialytic plasma bicarbonate (or total carbon dioxide) concentrations can be calculated after altering the hemodialysis treatment prescription. Example calculations showed that the H+ mobilization model when considered as a pseudo-one-compartment model predicted increases or decreases in plasma total carbon dioxide concentrations throughout the entire treatment when the dialysate bicarbonate concentration is increased or decreased, respectively, during conventional thrice weekly hemodialysis treatments. It was further shown that this model allowed prediction of the change in plasma total carbon dioxide concentration after transfer of patients from conventional thrice weekly to daily hemodialysis using both bicarbonate and lactate as dialysate buffer bases. The H+ mobilization model can predict changes in plasma bicarbonate or total carbon dioxide concentration during hemodialysis after altering the hemodialysis treatment prescription.

Toadfish (Opsanus tau) essentially lacking circulating erythrocytes were pre pared by repeated exchange transfusion with serum. The rate of nitrogen secretion is not changed by removal of the erythrocytes. Oxygen secretion is slowed dras tically. This shows that nitrogen secretion does not require erythrocytes and is not driven by oxygen secretion. In the absence of circulating erythrocytes, oxygen and nitrogen are brought into the swimbladder in proportion to their concentrations in blood plasma. Carbon dioxide partial pressure in the secreted gas mixture is three to fourfold greater than the pressure generated by acidifying arterial blood. This implies counter-current multiplication of the small increment of carbon dioxide pressure brought about by acidification of the blood. In the presence of blood buffers, increased carbon dioxide pressure will increase blood bicarbonate. Three independent estimates indicate that, during gas secretion, gas gland blood is near pH 6.5. Total carbon dioxide (CO2, HCO3, CO3) is increased from the arterial value near 2 mM to about 14 mM, divided nearly equally between carbon dioxide and bicarbonate anion. The increment in total blood carbon dioxide concentration together with the well-known increment in lactate anion may serve to salt out inert gases from solution in blood plasma.

For those clinical laboratories equipped with a microprocessor-controlled gas analyser, an extremely simple method is described for the determination of the total carbon dioxide content in various biological fluids. Since this method needs only 20 microL of blood plasma or is less dependent on the original total carbon dioxide content, it is especially suited for paediatric purposes. With our procedure the time necessary for one determination equals the time for one capillary blood gas analysis.

Summary The oxygen consumption rate (ṀO2) for Potamonauteus warreni Calman (= Potamon warreni (Calman) kept in 25 °C water was 34,4 μmol 1−1 O2 kg−1 and after 72 hours in 98% R.H. air the rate was 31,9 μmol 1−1 O2 kg−1 min−1. The ṀO2 values for each of the two groups are not significantly different (P > 0,05). The partial oxygen tension of pre-branchial (v = venous) haemolymph (PvCO2) is 15,3 mm Hg in water and 13,0 mm Hg in air); partial carbon dioxide tension of pre-branchial (v) haemolymph (PvCO2) is 13,2 mm Hg in water and 13,0 mm Hg in air); the total carbon dioxide concentration in pre-branchial (v) haemolymph (CvCO2) tot. is 12,3 mmol 1−1 in air and 13,9 mmol 1−1 in water) are not significantly different for the two groups (P > 0,05). The haemolymph pH and the lactate concentration for crabs in water was found to be 7,51 and 0,38 mmol 1−1 respectively. No significant differences were found in pre-branchial haemolymph oxygen tension, carbon dioxide tension, total carbon dioxide content, haemolymph pH, lactate level, chloride concentration, P50 and haemocyanin-oxygen cooperativity in control crabs kept in water, and experimental crabs held in air for 72 hours. The chloride concentration, (327,0 mmol 1−1) for crabs kept in water does not differ from that of crabs held in air for 72 hours but is at least 15% higher than the sodium concentration (255 mmol 1−1) for crabs kept in water. The gill surface area is 520 mm2 g−1 wet body mass; on average 9,2 gill platelets (lamellae) can be found on a gill length of one millimetre. Each lamella is spaced 60–70 μm apart, each with a thickness of 30–40 μm. It is concluded that P. warreni may be described as a truly amphibious fresh-water crab.

A new analytical procedure for total carbon dioxide in seawater was developed: a capillary-type isotachophoresis which applied a tubular microporous PTFE membrane as a preliminary enrichment was used. Carbon dioxide was generated by adding sulfuric acid to seawater samples, permeated through a tubular microporous PTFE membrane and dissolved in sodium hydroxide solution for the separation from large amounts of coexisting anions, such as chloride and sulfate ions. A linear working curve was obtained for artificial seawater samples containing up to 40 mg/l of total carbon dioxide. The proposed method was applied to the determination of total carbon dioxide in surface and bottom seawater samples. Concentrations of the total of free carbon dioxide and carbonic acid, hydrogencarbonate and carbonate ions in these samples were calculated from the concentration of total carbon dioxide, temperature, pH and salinity of samples measured in situ.

Determination of total carbon dioxide in blood and plasma by means of the cediometer. Theory and experimental verification

Increasing levels of atmospheric greenhouse gases due to fossil fuel use, deforestation and other anthropogenic sources have changed the global climate. Global warming is the most widespread problem of the new millennium. Carbon dioxide (CO2) is the most important greenhouse gas released as a result of human activities. "Stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system" is the main objective of the UNFCCC. To help achieve this, the Protocol allows developed nations to credit removals of greenhouse gas emissions by natural sinks that store carbon. Forest based land use systems such as natural forests, forest plantations and agroforestry systems sequester CO2, through the C stored in their biomass. Management of forests and agroforestry systems is identified as the most promising option to mitigate atmospheric Carbon dioxide (CO2). The objective of the present study was to investigate the carbon sequestration potential of Kandyan Homegarden in Sri Lanka located in Kandy and Matale District. Two representative gardens were selected from each District in Kandy and Matale. After conducting a comprehensive vegetation survey done in 16, 10 x 10m plots in each garden in a 1 ha area located to capture the maximum variability in terms of tree density, topographic and edaphic differences. All the trees were measured for dbh and height and from the results dominant tree species which contribute to the long term carbon sequestration were selected using Important Value Index. Trees were then categorized into diameter classes and a tree each from each diameter class was selected for detailed measurements including stem and canopy volume. Representative number of trees per diameter class was destructively sampled to get the weight measurements and these were used to extrapolate the weight of the rest of the trees according to the volumes estimated. In this way the total aboveground biomass and carbon lodged in these gardens were arrived at. The potential to sequester carbon dioxide without being emitted to the atmosphere was also calculated for the individual gardens and extrapolated to all the Homegardens in the particular district. According to the results, average total aboveground carbon content that could be lodged in the Homegardens and total carbon dioxide that can be stored as carbon without being emitted to the atmosphere in Kandy District (Agro ecological zone WM3a) are 89.98 t C/ha and 330.23 t C/ha and are 103.89 t C/ha and 381.27 t C/ha in Matale District (Agro ecological zone IUI) respectively. According to the Forestry Sector Master Plan (1995) the total extent of the Homegardens in Kandy District is 61,029 ha and 20,258 ha in Matale District. Therefore total aboveground carbon content and carbon dioxide stored in the form of carbon in the Homegardens in Kandy District vary between 5,397,404 t C (5 x 106) – 5,585,374 (5 x 10 6) t C and 19,888,182 t C (19.89 x 106 ) – 20,499,030 t C (20.45 x 106 ) respectively. In Matale District the total aboveground carbon content and carbon dioxide stored as carbon in homegardens vary between 2,455,674 t C (2.45 x 10 6 ) – 1,753,532 t C (1.75 x 10 6) and 9,012,176 t C (9.00 x 10 6 ) – 6,435,358 t C (6.44 x 10 6 ) respectively. Annual litterfall rate of selected Homegarden system in Kandy District is 8.16 t/ha and 9.38 t/ha in selected Homegarden in Matale District. Mean annual litterfall rate in Kandyan Homegarden system is equal to 8.77 tons ha-1 year-1.

Horse racing authorities impose a limit on the concentration of plasma 'total carbon dioxide' (TCO2), typically 36 mM with action taken above 37 mM, as measured by an electrochemical gas analyzer. It is of interest to understand the distribution of TCO2 in a 'normal' population of racehorses and determine probabilities of members of this population exceeding these current regulatory and action limits. TCO2 levels in equine plasma samples have been modelled for 12 months (2011-2012) of thoroughbred (3076 measurements) and standardbred (3788 measurements) data in Australia. The two populations have a common seasonal pattern, while the non-seasonal distributions differ. A single Gaussian distribution about the seasonal pattern explains the thoroughbred data, but there is evidence for a second Gaussian component for the standardbred horses. A Gaussian mixture model for standardbred horses gave a main component that matched the thoroughbred distribution, which was centred about 30.2 mM, and a smaller (about 20 % of the total density) Gaussian centred at 32.3 mM. The existence of a second, higher-meaned population of standardbred horses points to increased use of alkalinizing salts among a minority of trainers, whom still, however, maintain mostly legal levels of TCO2. Identification of this group can be used to direct intelligence-based testing with a view to limiting use of these products. Probabilities of exceeding limits are affected by seasonality, but the current rules remain conservative.

British Food Journal Volume 48 Issue 4 1946

BACKGROUND: Modeling toxic pulmonary edema for the purpose of studying the effectiveness of drugs is associated with difficulties in model validation and objectification of drug effectiveness criteria. To confirm the significance of changes in pulmonary coefficients and visual changes in lung tissue, acid-base balance and blood gas analysis are often used to objectify emerging gas exchange disorders. AIM: To investigate the acid-base composition and blood gases in mice during the progression of toxic pulmonary edema caused by inhalational phosgene exposure. MATERIAL AND METHODS: Toxic pulmonary edema was induced by exposing mice to phosgene at a dose corresponding to LCt50 in an inhalation chamber. Blood samples were analyzed for acid-base balance and gas parameters, including partial oxygen pressure (pO2), partial carbon dioxide pressure (pCO2), total hemoglobin (tHb), oxyhemoglobin (O2Hb), carboxyhemoglobin (COHb), methemoglobin (MetHb), reduced hemoglobin (RHb), oxygen saturation (sO2), oxygen concentration (O2ct), oxygen capacity (O2cap), partial oxygen pressure at 50 % saturation (P50), total carbon dioxide (tCO2), true and standard bicarbonate (HCO3–, SBC), actual and standard base excess (BEb, BEecf), anion gap, lactate, and concentrations of sodium, potassium, chloride, and ionized calcium. Measurements were performed using a gas analyzer at 30 minutes, 3 hours, and 24 hours after exposure initiation. RESULTS: Significant shifts in blood gas composition and acid-base balance were observed 3 hours after pulmonary edema initiation. These included decreased acid-base balance, reduced oxyhemoglobin levels, lowered oxygen saturation, and elevated partial carbon dioxide pressure, indicating respiratory insufficiency and compensated respiratory acidosis. Major changes in acid-base parameters were observed after 24 hours, with normalization of pH accompanied by increases in true and standard bicarbonate levels, as well as total carbon dioxide content. Changes in actual and standard base excess were observed, reflecting a reduction in base deficit. Electrolyte levels remained unchanged in all experimental groups throughout all observation periods. CONCLUSIONS: The study elucidated the progression of respiratory hypoxia during toxic pulmonary edema and confirmed that respiratory hypoxia serves as a key pathogenic link, leading to significant disruptions in energy metabolism during the progression of pulmonary edema.

Blood pH, carbon dioxide and oxygen partial pressures, bicarbonate, total carbon dioxide, base excess, standard bicarbonate and oxygen saturation concentrations were measured by blood gas analyses in a study of assessment of the acid-base status in young calves. Venous blood samples were taken from 80 healthy female Holstein calves, from four to 30 days of age. The calves were divided in two groups based on the interval between the morning milk feeding and the blood sample collection (up to 30 minutes or over two hours). Greater alkali reserve and higher carbon dioxide pressure values were observed later than 2h after milk feeding, supporting the influence of the diet on the acid-base balance of calves during the milk feeding phase.