Carbonic Acid: Carbonic acid (H2C03). The hypothetical acid of carbon dioxide and water. It exists only in the form of its salts (carbonates), acid salts (hydrogen carbonates), amines (carbamic acid), and acid chlorides (carbonyl chloride). (From Grant & Hackh's Chemical Dictionary, 5th ed)Histamine Agents: Drugs used for their actions on histaminergic systems. Included are drugs that act at histamine receptors, affect the life cycle of histamine, or affect the state of histaminergic cells.Carbonates: Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)Carbonic Anhydrases: A family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. They play an important role in the transport of CARBON DIOXIDE from the tissues to the LUNG. EC Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.Bicarbonates: Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Calcium Carbonate: Carbonic acid calcium salt (CaCO3). An odorless, tasteless powder or crystal that occurs in nature. It is used therapeutically as a phosphate buffer in hemodialysis patients and as a calcium supplement.United States Government Agencies: Agencies of the FEDERAL GOVERNMENT of the United States.Nisin: A 34-amino acid polypeptide antibiotic produced by Streptococcus lactis. It has been used as a food preservative in canned fruits and vegetables, and cheese.Judgment: The process of discovering or asserting an objective or intrinsic relation between two objects or concepts; a faculty or power that enables a person to make judgments; the process of bringing to light and asserting the implicit meaning of a concept; a critical evaluation of a person or situation.Dry Ice: A solid form of carbon dioxide used as a refrigerant.Dictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Gases: The vapor state of matter; nonelastic fluids in which the molecules are in free movement and their mean positions far apart. Gases tend to expand indefinitely, to diffuse and mix readily with other gases, to have definite relations of volume, temperature, and pressure, and to condense or liquefy at low temperatures or under sufficient pressure. (Grant & Hackh's Chemical Dictionary, 5th ed)Dictionaries, ChemicalTerminology as Topic: The terms, expressions, designations, or symbols used in a particular science, discipline, or specialized subject area.Salicylic Acid: A compound obtained from the bark of the white willow and wintergreen leaves. It has bacteriostatic, fungicidal, and keratolytic actions.Arabidopsis Proteins: Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.Arabidopsis: A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.Carbonic Anhydrase II: A cytosolic carbonic anhydrase isoenzyme found widely distributed in cells of almost all tissues. Deficiencies of carbonic anhydrase II produce a syndrome characterized by OSTEOPETROSIS, renal tubular acidosis (ACIDOSIS, RENAL TUBULAR) and cerebral calcification. EC 4.2.1.-Octamer Transcription Factors: A family of POU domain factors that bind the octamer motif ATTTGCAT in enhancer and PROMOTER REGIONS to regulate GENE EXPRESSION.Carbonic Anhydrase Inhibitors: A class of compounds that reduces the secretion of H+ ions by the proximal kidney tubule through inhibition of CARBONIC ANHYDRASES.Authorship: The profession of writing. Also the identity of the writer as the creator of a literary production.Knowledge Bases: Collections of facts, assumptions, beliefs, and heuristics that are used in combination with databases to achieve desired results, such as a diagnosis, an interpretation, or a solution to a problem (From McGraw Hill Dictionary of Scientific and Technical Terms, 6th ed).Geology: The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)EstersAcid-Base Equilibrium: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.Acidosis, Respiratory: Respiratory retention of carbon dioxide. It may be chronic or acute.Insulin, Regular, Human: Regular insulin preparations that contain the HUMAN insulin peptide sequence.Diamide: A sulfhydryl reagent which oxidizes sulfhydryl groups to the disulfide form. It is a radiation-sensitizing agent of anoxic bacterial and mammalian cells.Access to Information: Individual's rights to obtain and use information collected or generated by others.Formaldehyde: A highly reactive aldehyde gas formed by oxidation or incomplete combustion of hydrocarbons. In solution, it has a wide range of uses: in the manufacture of resins and textiles, as a disinfectant, and as a laboratory fixative or preservative. Formaldehyde solution (formalin) is considered a hazardous compound, and its vapor toxic. (From Reynolds, Martindale The Extra Pharmacopoeia, 30th ed, p717)Buffers: A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.HEPES: A dipolar ionic buffer.Tromethamine: An organic amine proton acceptor. It is used in the synthesis of surface-active agents and pharmaceuticals; as an emulsifying agent for cosmetic creams and lotions, mineral oil and paraffin wax emulsions, as a biological buffer, and used as an alkalizer. (From Merck, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p1424)Phosphates: Inorganic salts of phosphoric acid.African Americans: Persons living in the United States having origins in any of the black groups of Africa.Indians, North American: Individual members of North American ethnic groups with ancient historic ancestral origins in Asia.Science: The study of natural phenomena by observation, measurement, and experimentation.Asian Americans: Persons living in the United States having origins in any of the original peoples of the Far East, Southeast Asia, or the Indian subcontinent.Mexican Americans: Persons living in the United States of Mexican descent.United StatesHispanic Americans: Persons living in the United States of Mexican (MEXICAN AMERICANS), Puerto Rican, Cuban, Central or South American, or other Spanish culture or origin. The concept does not include Brazilian Americans or Portuguese Americans.Dihydroxyacetone Phosphate: An important intermediate in lipid biosynthesis and in glycolysis.Citric Acid Cycle: A series of oxidative reactions in the breakdown of acetyl units derived from GLUCOSE; FATTY ACIDS; or AMINO ACIDS by means of tricarboxylic acid intermediates. The end products are CARBON DIOXIDE, water, and energy in the form of phosphate bonds.Dihydroxyacetone: A ketotriose compound. Its addition to blood preservation solutions results in better maintenance of 2,3-diphosphoglycerate levels during storage. It is readily phosphorylated to dihydroxyacetone phosphate by triokinase in erythrocytes. In combination with naphthoquinones it acts as a sunscreening agent.TriosesCosmic Radiation: High-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.Neutrons: Electrically neutral elementary particles found in all atomic nuclei except light hydrogen; the mass is equal to that of the proton and electron combined and they are unstable when isolated from the nucleus, undergoing beta decay. Slow, thermal, epithermal, and fast neutrons refer to the energy levels with which the neutrons are ejected from heavier nuclei during their decay.Atmosphere: The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)Saturn: The sixth planet in order from the sun. It is one of the five outer planets of the solar system. Its twelve natural satellites include Phoebe and Titan.Extraterrestrial Environment: The environment outside the earth or its atmosphere. The environment may refer to a closed cabin (such as a space shuttle or space station) or to space itself, the moon, or other planets.Solar Activity: Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)Carbon: A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.

Modifications of proteins by polyunsaturated fatty acid peroxidation products. (1/33)

The ability of unsaturated fatty acid methyl esters to modify amino acid residues in bovine serum albumin (BSA), glutamine synthetase, and insulin in the presence of a metal-catalyzed oxidation system [ascorbate/Fe(III)/O(2)] depends on the degree of unsaturation of the fatty acid. The fatty acid-dependent generation of carbonyl groups and loss of lysine residues increased in the order methyl linoleate < methyl linolenate < methyl arachidonate. The amounts of alkyl hydroperoxides, malondialdehyde, and a number of other aldehydes that accumulated when polyunsaturated fatty acids were oxidized in the presence of BSA were significantly lower than that observed in the absence of BSA. Direct treatment of proteins with various lipid hydroperoxides led to a slight increase in the formation of protein carbonyl derivatives, whereas treatment with the hydroperoxides together with Fe(II) led to a substantial increase in the formation of protein carbonyls. These results are consistent with the proposition that metal-catalyzed oxidation of polyunsaturated fatty acids can contribute to the generation of protein carbonyls by direct interaction of lipid oxidation products (alpha,beta-unsaturated aldehydes) with lysine residues (Michael addition reactions) and also by interactions with alkoxyl radicals obtained by Fe(II) cleavage of lipid hydroperoxides that are formed. In addition, saturated aldehydes derived from the polyunsaturated fatty acids likely react with lysine residues to form Schiff base adducts.  (+info)

Cryopreservation reduces the ability of hamster 2-cell embryos to regulate intracellular pH. (2/33)

Vitrification of hamster 2-cell embryos impairs the activity of both the Na(+)/H(+) antiporter and HCO(3)(-)/Cl(-) exchanger; the two transport proteins responsible for the regulation of intracellular pH (pHi). The activities of both the Na(+)/H(+) antiporter and HCO(3)(-)/Cl(-) exchanger were significantly reduced at 4 h following warming compared to freshly collected embryos. Normal levels of activity of both transporters were not restored until 6 h after warming. Thus, cryopreservation of cleavage stage hamster embryos has a detrimental effect on their ability to maintain intracellular ionic homeostasis. Impairment of these pHi regulatory proteins resulted in the pHi of embryos being significantly elevated from the control values of 1.2 to 7.35 for approximately 4 h after warming. In addition, an elevated pHi value significantly impaired oxidative metabolism. Therefore, the loss in developmental competence of embryos following cryopreservation may in part be explained by a reduced ability to regulate intracellular pH that results in perturbations in metabolism and disruption of energy production.  (+info)

Extracellular HCO(3)(-) dependence of electrogenic Na/HCO(3) cotransporters cloned from salamander and rat kidney. (3/33)

We studied the extracellular [HCOabstract (3) (-)] dependence of two renal clones of the electrogenic Na/HCO(3) cotransporter (NBC) heterologously expressed in Xenopus oocytes. We used microelectrodes to measure the change in membrane potential (DeltaV(m)) elicited by the NBC cloned from the kidney of the salamander Ambystoma tigrinum (akNBC) and by the NBC cloned from the kidney of rat (rkNBC). We used a two-electrode voltage clamp to measure the change in current (DeltaI) elicited by rkNBC. Briefly exposing an NBC-expressing oocyte to HCOabstract (3 )(-)/CO(2) (0.33-99 mM HCOabstract (3)(-), pH(o) 7.5) elicited an immediate, DIDS (4, 4-diisothiocyanatostilbene-2,2-disulfonic acid)-sensitive and Na(+)-dependent hyperpolarization (or outward current). In DeltaV(m) experiments, the apparent K(m ) for HCOabstract (3)(-) of akNBC (10. 6 mM) and rkNBC (10.8 mM) were similar. However, under voltage-clamp conditions, the apparent K(m) for HCOabstract (3)(-) of rkNBC was less (6.5 mM). Because it has been reported that SOabstract (3)(=)/HSO abstract (3)(-) stimulates Na/HCO(3 ) cotransport in renal membrane vesicles (a result that supports the existence of a COabstract (3)(=) binding site with which SOabstract (3)(=) interacts), we examined the effect of SOabstract (3)(=)/HSO abstract (3)(-) on rkNBC. In voltage-clamp studies, we found that neither 33 mM SOabstract (4)(=) nor 33 mM SOabstract (3) (=)/HSOabstract (3)(-) substantially affects the apparent K(m) for HCO abstract (3)(-). We also used microelectrodes to monitor intracellular pH (pH(i)) while exposing rkNBC-expressing oocytes to 3.3 mM HCOabstract (3 )(-)/0.5% CO(2). We found that SO abstract (3)(=)/HSOabstract (3 )(-) did not significantly affect the DIDS-sensitive component of the pH(i) recovery from the initial CO(2 )-induced acidification. We also monitored the rkNBC current while simultaneously varying [CO(2)](o), pH(o), and [COabstract (3)(=)](o) at a fixed [HCOabstract (3)(-)](o) of 33 mM. A Michaelis-Menten equation poorly fitted the data expressed as current versus [COabstract (3)(=)](o ). However, a pH titration curve nicely fitted the data expressed as current versus pH(o). Thus, rkNBC expressed in Xenopus oocytes does not appear to interact with SOabstract (3 )(=), HSOabstract (3)(-), or COabstract (3)(=).  (+info)

The effect of feeding on the respiratory activity of the sloth. (4/33)

The aim of the present study was to confirm whether feeding influences the resting breathing rate and to observe possible alterations in blood gas and pH levels produced by feeding in unanesthetized sloths (Bradypus variegatus). Five adult male sloths (4.1 +/- 0.6 kg) were placed daily in an experimental chair for a period of at least 4 h for sitting adaptation. Five measurements were made for each sloth. However, the sloths one, two and five were studied once and the sloths three and four were studied twice. Breathing rate was determined with an impedance meter and the output signal was digitized. Arterial blood samples were collected for blood gas analysis with a BGE electrolytes analyzer and adjusted for the animal's body temperature and hemoglobin content. The data are reported as mean +/- SD and were collected during the resting period (8:00-10:00 h) and during the feeding period (16:00-18:00 h). The mean breathing rate increased during mastication of ymbahuba leaves (rest: 5.0 +/- 1, feeding: 10 +/- 1 bpm). No significant alterations were observed in arterial pH (rest: 7.42 +/- 0.05, feeding: 7.45 +/- 0.03), PCO2 (rest: 35.2 +/- 5.3, feeding: 33.3 +/- 4.4 mmHg) or PO2 (rest: 77.5 +/- 8.2, feeding: 78.4 +/- 5.2 mmHg) levels. These results indicate that in unanesthetized sloths 1) feeding evokes an increase in breathing rate without a significant change in arterial pH, PCO2 or PO2 levels, and 2) the increase in breathing rate produced by feeding probably is due to the act of mastication.  (+info)

Foraminiferal calcification response to glacial-interglacial changes in atmospheric CO2. (5/33)

A record of foraminiferal shell weight across glacial-interglacial Termination I shows a response related to seawater carbonate ion concentration and allows reconstruction of a record of carbon dioxide in surface seawater that matches the atmospheric record. The results support suggestions that higher atmospheric carbon dioxide directly affects marine calcification, an effect that may be of global importance to past and future changes in atmospheric CO2. The process provides negative feedback to the influence of marine calcification on atmospheric carbon dioxide and is of practical importance to the application of paleoceanographic proxies.  (+info)

Carbon dioxide combining properties of the blood of the shore crab Carcinus maenas (L): carbon dioxide solubility coefficient and carbonic acid dissociation constants. (6/33)

The carbon dioxide solubility coefficient, alphaCO2, and the apparent carbonic acid dissociation constants, K'1 and K'2 were estimated in the serum of the crab Carcinus maenas at various temperatures and ionic strengths. At 15 degrees C, the indirectly determined alphaCO2 value is 0-0499 m-mole l-1 torr-1 for crabs living in normal sea water (salinity ca. 35 percent). It is apparently independent of the serum protein concentration and of the stage of the moulting cycle. For crabs living in undiluted sea water, the mean pK'1 value, determined either gasometrically or titrimetrically, is 6-027 at 15 degrees C. At the same temperature, pK'2=9-29. These values approximate to those of sea water at 35 percent salinity. pK'1 drops as temperature rises; the measured deltapK'1/deltat is -0-0053 pH unit degrees C-1 between 10 and 30 degrees C. PK'1 rises as the ionic strength is lowered. Alignment nomograms have been constructed for the determination of alphaCO2, pK'1 and pK'2 values in relation to various conditions of temperature and salinity.  (+info)

Oxidized tissue proteins after intestinal reperfusion injury in rats. (7/33)

PURPOSE: To analyse if the carbonyl proteins measurement could be validated as a method that allows the identification of an intestinal oxidative stress after ischemia and reperfusion injury. METHODS: Twenty-five male Wistar rats (n = 21) weighting 200 to 250 g were divided into three groups. Group I--control (n = 10). Group II--sham (n = 5) and Group III (n = 10) subjected to 60 minutes of intestinal ischemia and equal period of reperfusion. For this purpose it was clamped the superior mesenteric artery in its distal third. Histological changes and carbonyl protein levels were determined in the samples of all groups. In group III, samples of both normal and reperfused ileal segment were studied. RESULTS: All the reperfused segments showed mucosal and submucosal swelling and inflammatory infiltrate of the lamina propria. Levels of carbonyl protein rose in group III, including in the non-ischemic segments. The sensitivity and specificity of the carbonyl protein tissue levels were respectively 94% and 88%. CONCLUSION: The carbonyl protein method is a useful biologic marker of oxidative stress after the phenomenon of intestinal ischemia and reperfusion in rats. It was also noteworthy that the effects of oxidative stress could be seen far from the locus of the primary injury.  (+info)

Isolation and characterization of a novel uronic acid-containing acidic glycosphingolipid from the ascidian Halocynthia roretzi. (8/33)

A novel uronic acid-containing glycosphingolipid (UGL-1) was isolated from the ascidian Halocynthia roretzi. UGL-1 was prepared from chloroform-methanol extracts and purified by the use of successive column chromatography on DEAE-Sephadex, Florisil, and Iatrobeads. Chemical structural analysis was performed using methylation analysis, gas chromatography, gas chromatography-mass spectrometry, matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry, and 1H-NMR spectra. The chemical structure of UGL-1 was determined to be a glucuronic acid-containing glycosphingolipid, Galbeta1-4(Fucalpha1-3)GlcAbeta1-1Cer. The ceramide component was composed of C16:0 and C18:0 acids and C16-, C17-, and C18-phytosphingosines as major components.  (+info)

  • It is not exerted by the chief mass of the air, but in a high degree by aqueous vapour and carbonic acid, which are present in the air in small quantities. (
  • Carbonic acid, which is formed by the dissolution and hydrolysis of CO 2 in water, is the major natural leaching agent in many temperate ecosystems. (
  • The preparation of carbonated water, sparkling wine, and other aerated drinks involve the use of carbonic acid. (
  • Tyndall held the opinion that the water-vapour has the greatest influence, whilst other authors, for instance Lecher and Pernter, are inclined to think that the carbonic acid plays the more important part. (
  • As we have now determined, in the manner described, the values of the absorption-coefficients for all kinds of rays, it will with the help of Langley's figures be possible to calculate the fraction of the heat from a body at 15°C. (the earth) which is absorbed by an atmosphere that contains specified quantities of carbonic acid and water-vapour. (
  • Therefore it is obvious that during the period of three years the albuminous substances of the beer yeast water mixed with sugared water and exposed to ordinary air, but under conditions in which animalcules and or moulds were not developed, had absorbed 2.7 per cent of oxygen, which they had partially converted into carbonic acid. (
  • Extra gas will dissolve in water and make more carbonic acid. (
  • Hunter, SE & Savage, PE 2003, ' Acid-catalyzed reactions in carbon dioxide-enriched high-temperature liquid water ', Industrial and Engineering Chemistry Research , vol. 42, no. 2, pp. 290-294. (
  • To attempt this experiment, you'll need some purple cabbage indicator water, which changes colors when acids and bases are added to it. (
  • In several days, you will see that the water has changed colors because the exhaled carbon dioxide has combined with the water to create carbonic acid. (
  • Carbonated water releases CO 2 bubbles for many minutes after pressure is released (dissolved carbonic acid reforming), which is an important presentation effect that other gases do not generally have. (
  • The addition of weak acids to water helps with neutralising this effect. (
  • Alkalinity is a measure of the acid-neutralizing capacity of water. (
  • The dissolved CO 2(aq) reacts with water molecules to form carbonic acid (H 2 CO 3 *), which is very unstable and quickly dissociates, yielding H + and a bicarbonate ion (HCO 3 - ) (Equations 2 and 3). (
  • When Na 2 HPO4 2− (the weak acid) comes into contact with a strong base, such as sodium hydroxide (NaOH), the weak acid reverts back to the weak base and produces water. (
  • The enzymatic conversion of starch to sugar proceeds more readily in an alkaline environment(high PH).The conversion of sugar to starch occurs more readily in an acidic environment (low Ph).During the night, when photosynthesis is not taking place, carbon dioxide accumulates in leaf cells it combines with water to form carbonic acid. (
  • Carbonic acid is often described as a respiratory acid since it is the only acid that is exhaled in the gaseous state by the human lungs. (
  • From the illustration provided above, it can be understood that the structure of carbonic acid consists of one carbon-oxygen double bond and two carbon-oxygen single bonds. (
  • Moreover, all absorbed oxygen is recovered in carbonic acid, less the difference that may always result from the coefficients of solubility of two gases in the experimental liquid. (
  • Phosphoric acid is added to impart a tart flavor and to counteract the sweetness of the sugar or artificial sweeteners, and also as a preservative to prevent the growth of mold. (
  • Hyperlipidemia, along with lifestyle modifications to make therapeutic approach and do nothexceed g daily in patients with severe symptoms fever odynophagia dysphagia retrosternal pain signs severe dehydration leading to cardiopulmonary arrest and rhabdomyolysis which can be ollowed up or down regulation of paco, effectively allowing carbonic acid to the two conditions can suggest an umn lesion as well as symptoms that may be insidious and subacute. (
  • Citric acid is added, especially to fruit flavored sodas to give a bit more of a zippy flavor. (
  • Carbonic acid is the chemical compoond wi the formula H 2 CO 3 (equivalently OC(OH) 2 ). (