Alkalosis: A pathological condition that removes acid or adds base to the body fluids.Alkalosis, Respiratory: A state due to excess loss of carbon dioxide from the body. (Dorland, 27th ed)Acid-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.Acid-Base Imbalance: Disturbances in the ACID-BASE EQUILIBRIUM of the body.Hypokalemia: Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)Bartter Syndrome: A group of disorders caused by defective salt reabsorption in the ascending LOOP OF HENLE. It is characterized by severe salt-wasting, HYPOKALEMIA; HYPERCALCIURIA; metabolic ALKALOSIS, and hyper-reninemic HYPERALDOSTERONISM without HYPERTENSION. There are several subtypes including ones due to mutations in the renal specific SODIUM-POTASSIUM-CHLORIDE SYMPORTERS.Acidosis: A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.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.Acidosis, Respiratory: Respiratory retention of carbon dioxide. It may be chronic or acute.Sodium Bicarbonate: A white, crystalline powder that is commonly used as a pH buffering agent, an electrolyte replenisher, systemic alkalizer and in topical cleansing solutions.Gitelman Syndrome: An inherited renal disorder characterized by defective NaCl reabsorption in the convoluted DISTAL KIDNEY TUBULE leading to HYPOKALEMIA. In contrast with BARTTER SYNDROME, Gitelman syndrome includes hypomagnesemia and normocalcemic hypocalciuria, and is caused by mutations in the thiazide-sensitive SODIUM-POTASSIUM-CHLORIDE SYMPORTERS.Hypocapnia: Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.Carbon Dioxide: A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.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)Solute Carrier Family 12, Member 3: Na-Cl cotransporter in the convoluted segments of the DISTAL KIDNEY TUBULE. It mediates active reabsorption of sodium and chloride and is inhibited by THIAZIDE DIURETICS.Hyperventilation: A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.HEPES: A dipolar ionic buffer.Myoclonus: Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASES; (e.g., EPILEPSY, MYOCLONIC). Nocturnal myoclonus is the principal feature of the NOCTURNAL MYOCLONUS SYNDROME. (From Adams et al., Principles of Neurology, 6th ed, pp102-3).Partial Pressure: The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Ammonium Chloride: An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.Kidney Tubules, Distal: The portion of renal tubule that begins from the enlarged segment of the ascending limb of the LOOP OF HENLE. It reenters the KIDNEY CORTEX and forms the convoluted segments of the distal tubule.

*  Nurse Nacole | Nursing Resources: Nursing Tip of the Day! - Critical Care Nursing
A metabolic alkalosis is classified as chloride responsive or chloride resistant, based on the spot urine chloride ... A chloride-responsive metabolic alkalosis presents with a low urinary chloride concentration of , 15 mEq/L. ...
  http://www.nursenacole.com/2012/08/nursing-tip-of-day-critical-care-nursing_8.html
*  Clinical Approach to Metabolic Alkalosis
Loss of gastric fluid and HCl due to vomiting is the most common cause of metabolic alkalosis.. *Vomiting may be caused by ... Loss of gastric fluid and HCl due to vomiting is the most common cause of metabolic alkalosis.. *Vomiting may be caused by ... Loss of gastric fluid and HCl due to vomiting is the most common cause of metabolic alkalosis.. *Vomiting may be caused by ... Obtain historical data to pinpoint the nature of the disease causing metabolic alkalosis.. * Ask the patient about history of ...
  http://doctorsgates.blogspot.gr/2010/11/clinical-approach-to-metabolic.html
*  Mixed alkalosis and acidosis | Article about mixed alkalosis and acidosis by The Free Dictionary
a change in the acid-alkaline balance of the organism as a result of... Explanation of mixed alkalosis and acidosis ... Find out information about mixed alkalosis and acidosis. A condition of decreased alkali reserve of the blood and other body ... redirected from mixed alkalosis and acidosis). Also found in: Dictionary, Thesaurus, Medical. acidosis. [‚as·ə′dō·səs] ( ... Mixed alkalosis and acidosis , Article about mixed alkalosis and acidosis by The Free Dictionary https://encyclopedia2. ...
  http://encyclopedia2.thefreedictionary.com/mixed+alkalosis+and+acidosis
*  acidosis or alkalosis | Sciforums
acidosis or alkalosis. Discussion in 'Chemistry' started by sue.911, May 26, 2008. ... explaining the relationship between pH and hydrogen concentration and how this may cause acidosis or alkalosis? ...
  http://www.sciforums.com/threads/acidosis-or-alkalosis.81319/
*  What is alkalosis? definition and meaning - BusinessDictionary.com
Definition of alkalosis: Change in body fluids and tissue that makes them more alkaline than normal, caused by failure of the ...
  http://www.businessdictionary.com/definition/alkalosis.html
*  Most recent papers with the keyword Metabolic alkalosis pediatric | Read by QxMD
Metabolic alkalosis is a common acid-base disturbance occurring in critically ill pediatric patients. Acetazolamide and ... After the correction of systemic metabolic alkalosis and pH normalization, cerebrospinal fluid can keep a state of metabolic ... After the correction of systemic metabolic alkalosis and pH normalization, cerebrospinal fluid can keep a state of metabolic ... Acetazolamide therapy for metabolic alkalosis in critically ill pediatric patients.. Amir Bar, Jeff Cies, Kathleen Stapleton, ...
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*  ALKALOSIS IN CRITICALLY ILL PATIENTS | Anesthesiology | ASA Publications
ALKALOSIS IN CRITICALLY ILL PATIENTS You will receive an email whenever this article is corrected, updated, or cited in the ... ALKALOSIS IN CRITICALLY ILL PATIENTS. Anesthesiology 1 1974, Vol.40, 12. doi: ...
  http://anesthesiology.pubs.asahq.org/article.aspx?articleid=1976573
*  Alkalosis and Acidosis
Alkalosis. Respiratory. Causes. Too much anxiety often leads to hyperventilation or deep breathing, which releases too much ... On the other hand, when the pH goes above 7.45, then we say that alkalosis has occurred. We have a severe case of the former, ... Alkalosis. *Severe diarrhea causes excessive loss of body fluid. This is a major cause. ... Two major problems might arise - respiratory and metabolic acidosis and alkalosis. Let us now see what each means. ...
  http://pakitong.blogspot.com/2015/03/alkalosis-and-acidosis.html
*  Biology-Online • View topic - Respiratory vs metabolic acidosis/alkalosis
respiratory acidosis, metabolic acidosis, metabolic alkalosis or respiratory alkalosis (answer, metabolic alkalosis). Thanks! ... respiratory acidosis, metabolic acidosis, metabolic alkalosis or respiratory alkalosis (answer, metabolic acidosis). AND. A ... Respiratory acidosis/alkalosis is normally a result of a deviation from normal rates of CO2 exchange; that is to say, the body ... Metabolic acidosis/alkalosis can be attributed to a myriad of causes, from excessive vomiting, diabetes, diarrhea, lactate ...
  http://www.biology-online.org/biology-forum/about21238.html?hilit=Hypoventilation
*  Acid/Base Disorders: Metabolic Alkalosis - ONA
Cirrhotics on diuretics can have respiratory alkalosis and metabolic alkalosis: pH - 7.55, PaCO2 - 38 mmHg, Na+ - 140 mEq/L, K+ ... depicts some common causes of metabolic alkalosis.. Table II.. Differential diagnosis of metabolic alkalosis. If one is dealing ... Does this patient have metabolic alkalosis? * How does one make the diagnosis of metabolic alkalosis and differentiate simple ... How should patients with metabolic alkalosis be managed? * If you decide your patient has primary metabolic alkalosis, what ...
  http://www.oncologynurseadvisor.com/nephrology-hypertension/acidbase-disorders-metabolic-alkalosis/article/616251/
*  Severe metabolic alkalosis. | The BMJ
Severe metabolic alkalosis. Br Med J (Clin Res Ed) 1982; 284 :273 ... Severe metabolic alkalosis.. Br Med J (Clin Res Ed) 1982; 284 doi: https://doi.org/10.1136/bmj.284.6311.273-b (Published 23 ...
  http://www.bmj.com/content/284/6311/273.3
*  Respiratory&Metabolic Acidosis/Alkalosis | allnurses
I'm learning about ABG's and I don't understand how someone can have respiratory AND metabolic acidosis or alkalosis. It ... metabolic acidosis/alkalosis references to two different mechanisms of acid/base balance. Someone can experience respiratory ... I'm learning about ABG's and I don't understand how someone can have respiratory AND metabolic acidosis or alkalosis. It ...
  http://allnurses.com/general-nursing-discussion/respiratory-amp-metabolic-750397.html
*  Compensated alkalosis | Define Compensated alkalosis at Dictionary.com
Compensated alkalosis definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. Look ... compensated alkalosis in Medicine Expand. compensated alkalosis n. A rise in alkalinity that is compensated for by ...
  http://www.dictionary.com/browse/compensated-alkalosis
*  Dropbox - Potassium, Metabolic Alkalosis, monogenic HTN 2016.pdf
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*  Metabolic alkalosis | definition of metabolic alkalosis by Medical dictionary
What is metabolic alkalosis? Meaning of metabolic alkalosis medical term. What does metabolic alkalosis mean? ... Looking for online definition of metabolic alkalosis in the Medical Dictionary? metabolic alkalosis explanation free. ... Related to metabolic alkalosis: metabolic acidosis, respiratory alkalosis Metabolic Alkalosis. Definition. Metabolic alkalosis ... gastric alkalosis. alkalosis due to loss of gastric fluid because of persistent vomiting. See also hypochloremic alkalosis ( ...
  http://medical-dictionary.thefreedictionary.com/metabolic+alkalosis
*  Chronic cerebral intracellular alkalosis following forebrain ischemic insult in rats. | Stroke
Chronic cerebral intracellular alkalosis following forebrain ischemic insult in rats.. M Chopp, A M Vande Linde, H Chen, R ... Chronic cerebral intracellular alkalosis following forebrain ischemic insult in rats.. M Chopp, A M Vande Linde, H Chen, R ... Chronic cerebral intracellular alkalosis following forebrain ischemic insult in rats.. M Chopp, A M Vande Linde, H Chen, R ... In the ischemic group, alkalosis occurred primarily after 48-72 hours of recirculation. We speculate that brain tissue ...
  http://stroke.ahajournals.org/content/21/3/463
*  The Influence of Nonrespiratory Alkalosis on Cerebral Blood Flow in Cats | Stroke
The Influence of Nonrespiratory Alkalosis on Cerebral Blood Flow in Cats. J. L. PANNIER, G. DEMEESTER, I. LEUSEN ...
  http://stroke.ahajournals.org/content/5/3/324
*  The Effect of Dietary Alkalosis on the Growth Rate of Mouse Sarcoma | Cancer Research
The Effect of Dietary Alkalosis on the Growth Rate of Mouse Sarcoma. Robert D. Barnard ... The Effect of Dietary Alkalosis on the Growth Rate of Mouse Sarcoma ... The Effect of Dietary Alkalosis on the Growth Rate of Mouse Sarcoma ... The Effect of Dietary Alkalosis on the Growth Rate of Mouse Sarcoma ...
  http://cancerres.aacrjournals.org/content/15/3/2265
*  Alkalosis - Wikipedia
Alkalosis is usually divided into the categories of respiratory alkalosis and metabolic alkalosis or a combined respiratory/ ... metabolic alkalosis. Respiratory alkalosis is caused by hyperventilation, resulting in a loss of carbon dioxide. Compensatory ... Alkalosis is the result of a process reducing hydrogen ion concentration of arterial blood plasma (alkalemia). In contrast to ... Metabolic alkalosis can be caused by repeated vomiting, resulting in a loss of hydrochloric acid in the stomach contents. ...
  https://en.wikipedia.org/wiki/Alkalosis
*  Effects of respiratory alkalosis on human skeletal muscle metabolism at the onset of submaximal exercise.
The purpose of this study was to examine the effects of respiratory alkalosis on human skeletal muscle metabolism at rest and ... Alkalosis, Respiratory / metabolism*. Blood / metabolism. Exercise / physiology*. Glycogen / biosynthesis. Heart / physiology. ... The purpose of this study was to examine the effects of respiratory alkalosis on human skeletal muscle metabolism at rest and ... The results from the present study suggest that respiratory alkalosis may play an important role in lactate accumulation during ...
  http://www.biomedsearch.com/nih/Effects-respiratory-alkalosis-human-skeletal/12356901.html

Metabolic alkalosisRespiratory alkalosisAcid–base reaction: An acid–base reaction is a chemical reaction that occurs between an acid and a base. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems.Urine anion gap: The urine anion gap is calculated using measured ions found in the urine. It is used to aid in the differential diagnosis of metabolic acidosis.HypokalemiaROMK: The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (Kir1.1) that transports potassium out of cells.AcidosisBicarbonateRespiratory acidosisIntravenous sodium bicarbonateGitelman syndromeHypocapnia: Hypocapnia or hypocapnea also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. Hypocapnia usually results from deep or rapid breathing, known as hyperventilation.List of countries by carbon dioxide emissionsAlkaliphile: Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline (pH roughly 8.5-11) environments, growing optimally around a pH of 10.Hyperventilation syndromeHyperchloremiaGas analysis: Gas analysis could refer to any of the following:Palatal myoclonusPulmonary gas pressures: The factors that determine the values for alveolar pO2 and pCO2 are:Zinc ammonium chloride: Zinc ammonium chloride, also known as diammonium tetrachlorozincate(2-) (IUPAC name), is a zinc salt commonly used as a flux in the process of hot-dip galvanizing. The CAS registry number is 14639-97-5.

(1/239) Blockade of ATP-sensitive potassium channels in cerebral arterioles inhibits vasoconstriction from hypocapnic alkalosis in cats.

BACKGROUND AND PURPOSE: Recent studies have shown that the cerebral arteriolar dilation from hypercapnic acidosis is blocked by agents which inhibit KATP channels. These findings suggested that this response is due to opening of KATP channels. Because the repose to CO2 is a continuum, with hypercapnic acidosis causing vasodilation and hypocapnic alkalosis causing vasoconstriction, it would be expected that the response to hypocapnic alkalosis would be due to closing of KATP channels. There are no studies of the effect of inhibition of KATP channels on the response to hypocapnic alkalosis. METHODS: We investigated the effect of 3 agents that in earlier studies were found to inhibit KATP channels--NG-nitro-L-arginine, hydroxylysine, and glyburide--on the cerebral arteriolar constriction caused by graded hypocapnia induced by hyperventilation in anesthetized cats equipped with cranial windows. RESULTS: Hypocapnic alkalosis caused dose-dependent vasoconstriction that was inhibited completely by each of the 3 inhibitors of KATP channels. The blockade induced by these agents was eliminated in the presence of topical L-lysine (5 micromol/L). CONCLUSIONS: The findings show that agents which inhibit ATP-sensitive potassium channels in cerebral arterioles inhibit the vasoconstriction from hypocapnic alkalosis. These and earlier results showing that inhibition of KATP channels inhibited dilation from hypercapnic acidosis demonstrate that the response to CO2 in cerebral arterioles is mediated by the opening and closing of KATP channels.  (+info)

(2/239) Intracellular pH regulation by HCO3-/Cl- exchange is activated during early mouse zygote development.

We report here that at least one major pHi-regulatory mechanism, the HCO3-/Cl- exchanger, is quiescent in unfertilized mouse eggs but becomes fully activated during early development following fertilization. Zygotes (8-12 h postfertilization) exhibited a marked intracellular alkalinization upon external Cl- removal, which is indicative of active HCO3-/Cl- exchangers, in contrast to the very small response observed in eggs. In addition, efflux of Cl- from eggs upon external Cl- removal was much slower than that from zygotes, indicating additional pathways for Cl- to cross the plasma membrane in zygotes. Furthermore, while zygotes quickly recovered from an induced alkalosis, eggs exhibited only a slow, incomplete recovery. Following in vitro fertilization (IVF), increased HCO3-/Cl- exchanger activity was first detectable about 4 h postfertilization and reached the maximal level after about 8 h. The upregulation of HCO3-/Cl- exchanger activity after fertilization appeared to occur by activation of existing, inactive exchangers rather than by synthesis or transport of new exchangers, as the increase in activity following IVF was unaffected by inhibition of protein synthesis or by disruption of the Golgi apparatus or the cytoskeleton. This activation may depend on the Ca2+ transients which follow fertilization, as suppression of these transients, using the Ca2+ chelator BAPTA, reduced subsequent upregulation of HCO3-/Cl- exchanger activity by about 50%. Activation of pHi-regulatory systems may be a widespread feature of the earliest period of embryonic development, not restricted to species such as marine invertebrates as previously believed.  (+info)

(3/239) H+-K+-ATPases: regulation and role in pathophysiological states.

Molecular cloning experiments have identified the existence of two H+-K+-ATPases (HKAs), colonic and gastric. Recent functional and molecular studies indicate the presence of both transporters in the kidney, which are presumed to mediate the exchange of intracellular H+ for extracellular K+. On the basis of these studies, a picture is evolving that indicates differential regulation of HKAs at the molecular level in acid-base and electrolyte disorders. Of the two transporters, gastric HKA is expressed constitutively along the length of the collecting duct and is responsible for H+ secretion and K+ reabsorption under normal conditions and may be stimulated with acid-base perturbations and/or K+ depletion. This regulation may be species specific. To date there are no data to indicate that the colonic HKA (HKAc) plays a role in H+ secretion or K+ reabsorption under normal conditions. However, HKAc shows adaptive regulation in pathophysiological conditions such as K+ depletion, NaCl deficiency, and proximal renal tubular acidosis, suggesting an important role for this exchanger in potassium, HCO-3, and sodium (or chloride) reabsorption in disease states. The purpose of this review is to summarize recent functional and molecular studies on the regulation of HKAs in physiological and pathophysiological states. Possible signals responsible for regulation of HKAs in these conditions will be discussed. Furthermore, the role of these transporters in acid-base and electrolyte homeostasis will be evaluated in the context of genetically altered animals deficient in HKAc.  (+info)

(4/239) pH regulation of K(+) efflux from myocytes in isolated rat hearts: (87)Rb, (7)Li, and (31)P NMR studies.

This study investigates the effects of intracellular (pH(i)) and extracellular pH (pH(e)) on the efflux of Rb(+) and Li(+) in isolated rat hearts. (87)Rb and (7)Li NMR were used to measure Rb(+) and Li(+) content, respectively, of hearts, and (31)P NMR was used to monitor pH(i), pH(e), and phosphate levels. After 30-min equilibration with Rb(+) or Li(+), effluxes were initiated by switching perfusion to a Rb(+)- or Li(+)-free, high-K(+) (20.7 mM) Krebs-Henseleit buffer with 15 microM bumetanide. Monensin (2 microM) increased pH(i) from 7.10 +/- 0.05 to 7.32 +/- 0.07 and resulted in activation of Rb(+) efflux; the first-order rate constant (k x 10(3), in min(-1)) increased from 42 +/- 2 to 116 +/- 16. Glibenclamide (4 microM) did not inhibit monensin-activated Rb(+) efflux (k = 110 +/- 17), whereas quinine (0.2 mM) slightly inhibited it by 19 +/- 9%. Infusion of 15 mM NH(4)Cl during Rb(+) washout increased k for Rb(+) efflux by 93% (81 +/- 8), which was glibenclamide and quinine insensitive, and caused a transient increase in pH(i) to 7.25 +/- 0.08. Intracellular Li(+) inhibited NH(4)Cl-stimulated Rb(+) efflux by 55%. Monensin and NH(4)Cl stimulated Li(+) efflux by 40%, increasing k from 29 +/- 3 to 43 +/- 7 and 41 +/- 3, respectively. The stimulation was not sensitive to 10 microM dimethylamiloride. Intracellular acidosis that resulted from the washout of NH(4)Cl (pH 6.86 +/- 0.2) slightly inhibited Rb(+) efflux (k = 36 +/- 5), whereas NH(4)Cl itself in the absence of pH(i) changes did not markedly affect Rb(+) efflux. A moderate increase in pH(i) (7.17 +/- 0.06) produced by washout of 15 mM 2, 2-dimethylpropionate (DMP)-Tris from hearts preequilibrated with DMP did not markedly affect Rb(+) efflux. Neither global alkalosis (pH(i) 7.4, pH(e) 7.55) nor acidosis (pH(i) approximately pH(e) 6.8) produced by 3 mM Tris base or 5 mM MES, respectively, affected Rb(+) efflux. We suggest that intracellular alkalosis stimulates Rb(+) (K(+)) and Li(+) effluxes by activating a nonselective sarcolemmal K(+) (Li(+))/cation exchanger or a K(+) (Li(+))-anion symporter.  (+info)

(5/239) Renal responses of trout to chronic respiratory and metabolic acidoses and metabolic alkalosis.

Exposure to hyperoxia (500-600 torr) or low pH (4.5) for 72 h or NaHCO(3) infusion for 48 h were used to create chronic respiratory (RA) or metabolic acidosis (MA) or metabolic alkalosis in freshwater rainbow trout. During alkalosis, urine pH increased, and [titratable acidity (TA) - HCO(-)(3)] and net H(+) excretion became negative (net base excretion) with unchanged NH(+)(4) efflux. During RA, urine pH did not change, but net H(+) excretion increased as a result of a modest rise in NH(+)(4) and substantial elevation in [TA - HCO(-)(3)] efflux accompanied by a large increase in inorganic phosphate excretion. However, during MA, urine pH fell, and net H(+) excretion was 3.3-fold greater than during RA, reflecting a similar increase in [TA - HCO(-)(3)] and a smaller elevation in phosphate but a sevenfold greater increase in NH(+)(4) efflux. In urine samples of the same pH, [TA - HCO(-)(3)] was greater during RA (reflecting phosphate secretion), and [NH(+)(4)] was greater during MA (reflecting renal ammoniagenesis). Renal activities of potential ammoniagenic enzymes (phosphate-dependent glutaminase, glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, alanine aminotransferase, phosphoenolpyruvate carboxykinase) and plasma levels of cortisol, phosphate, ammonia, and most amino acids (including glutamine and alanine) increased during MA but not during RA, when only alanine aminotransferase increased. The differential responses to RA vs. MA parallel those in mammals; in fish they may be keyed to activation of phosphate secretion by RA and cortisol mobilization by MA.  (+info)

(6/239) The pathophysiological and molecular basis of Bartter's and Gitelman's syndromes.

Molecular defects affecting the transport of sodium, potassium and chloride in the nephron through the ROMK K+ channel, Na+/K+/2Cl- cotransporter, the Na+/Cl- cotransporter and chloride channel have been identified in patients with Bartter's and Gitelman's syndromes. Defects of the angiotensin II type I receptor and CFTR have also being described. These defects are simple (i.e., most are single amino acid substitutions) but affect key elements in tubular transport. The simplicity of the genetic defects may explain why the inheritance of these conditions remains unclear in most kindreds (i.e., not just recessive or dominant) and emphasises the crucial importance of the conformational structure of these channels. Application of this molecular information will allow the early genetic identification of patients with these syndromes and enable us to differentiate between the various disorders at a functional level. It may also identify a subgroup in which the heterozygous form may make patients potentially exquisitely sensitive to diuretics.  (+info)

(7/239) Defective processing and expression of thiazide-sensitive Na-Cl cotransporter as a cause of Gitelman's syndrome.

Gitelman's syndrome is an autosomal recessive disorder of salt wasting and hypokalemia caused by mutations in the thiazide-sensitive Na-Cl cotransporter. To investigate the pathogenesis of Gitelman's syndrome, eight disease mutations were introduced into the mouse thiazide-sensitive Na-Cl cotransporter and studied by functional expression in Xenopus oocytes. Sodium uptake into oocytes that expressed the wild-type clone was more than sevenfold greater than uptake into control oocytes. Uptake into oocytes that expressed the mutated transporters was not different from control. Hydrochlorothiazide reduced Na uptake by oocytes expressing the wild-type gene to control values but had no effect on oocytes expressing the mutant clones. Western blots of oocytes injected with the wild-type clone showed bands representing glycosylated (125 kDa) and unglycosylated (110 kDa) forms of the transport protein. Immunoblot of oocytes expressing the mutated clones showed only the unglycosylated protein, indicating that protein processing was disrupted. Immunocytochemistry with an antibody against the transport protein showed intense membrane staining of oocytes expressing the wild-type protein. Membrane staining was completely absent from oocytes expressing mNCC(R948X); instead, diffuse cytoplasmic staining was evident. In summary, the results show that several mutations that cause Gitelman's syndrome are nonfunctional because the mutant thiazide-sensitive Na-Cl cotransporter is not processed normally, probably activating the "quality control" mechanism of the endoplasmic reticulum.  (+info)

(8/239) Expression of rat kidney anion exchanger 1 in type A intercalated cells in metabolic acidosis and alkalosis.

By enzyme-linked in situ hybridization (ISH), direct evidence is provided that acid-secreting intercalated cells (type A IC) of both the cortical and medullary collecting ducts of the rat kidney selectively express the mRNA of the kidney splice variant of anion exchanger 1 (kAE1) and no detectable levels of the erythrocyte AE1 (eAE1) mRNA. Using single-cell quantification by microphotometry of ISH enzyme reaction, medullary type A IC were found to contain twofold higher kAE1 mRNA levels compared with cortical type A IC. These differences correspond to the higher intensity of immunostaining in medullary versus cortical type A IC. Chronic changes of acid-base status induced by addition of NH(4)Cl (acidosis) or NaHCO3 (alkalosis) to the drinking water resulted in up to 35% changes of kAE1 mRNA levels in both cortical and medullary type A IC. These experiments provide direct evidence at the cellular level of kAE1 expression in type A IC and show moderate capacity of type A IC to respond to changes of acid-base status by modulation of kAE1 mRNA levels.  (+info)