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At least 37 records · Page 2Linked to original sources
PubMed1990

Acute metabolic acidosis enhances circulating parathyroid hormone, which contributes to the renal response against acidosis in the rat.

Acute PTH administration enhances final urine acidification in the rat. HCl was infused during 3 h in rats to determine the parathyroid and renal responses to acute metabolic acidosis. Serum immunoreactive PTH (iPTH) concentration significantly increased and nephrogenous adenosine 3H,5H-cyclic monophosphate tended to increase during HCl loading in intact and adrenalectomized (ADX) rats despite significant increments in plasma ionized calcium. Strong linear relationships existed between serum iPTH concentration and arterial bicarbonate or proton concentration (P less than 0.0001). Serum iPth concentration and NcAMP remained stable in intact time-control rats and decreased in CaCl2-infused, nonacidotic animals. Urinary acidification was markedly reduced in parathyroidectomized (PTX) as compared with intact rats during both basal and acidosis states; human PTH-(1-34) infusion in PTX rats restored in a dose-dependent manner the ability of the kidney to acidify the urine and excrete net acid. Acidosis-induced increase in urinary net acid excretion was observed in intact, PTX, and ADX, but not in ADX-thyroparathyroidectomized rats. We conclude that (a) acute metabolic acidosis enhances circulating PTH activity, and (b) PTH markedly contributes to the renal response against acute metabolic acidosis by enhancing urinary acidification.

Acidosis↗
PubMed1994

Natural history and course of acquired lactic acidosis in adults. DCA-Lactic Acidosis Study Group.

STUDY OBJECTIVE: To determine the pathogenesis and clinical course of lactic acidosis in adults receiving standard medical care. DESIGN: Placebo arm of a 5-year prospective, randomized, blinded study comparing placebo and dichloroacetate as specific lactate-lowering therapy. Each patient received intravenous saline placebo in addition to conventional therapy. SETTING: Intensive care units of 10 tertiary care hospitals in North America. PATIENTS: One hundred twenty-six patients with lactic acidosis, defined as arterial blood lactate greater than or equal to 5 mmol/L and either arterial pH of less than or equal to 7.35 or base deficit greater than 6 mmol/L. Patients were followed for up to 6 months. MEASUREMENTS AND MAIN RESULTS: Mean +/- SD demographic entry data for 126 patients included: age 56 +/- 17 years, lactate 10.4 +/- 5.5 mmol/L, pH 7.24 +/- 0.14, calculated base deficit 14.1 +/- 5.4, arterial systolic blood pressure 103 +/- 29 mm Hg, Glasgow Coma score 7.9 +/- 4.9, and APACHE II score 19.2 +/- 8.1. Despite fluids and pressors, 32% of patients had systolic blood pressures of less than or equal to 90 mm Hg in association with sepsis (59%), cardiac failure (18%), or hemorrhage (18%). The most common causes of lactic acidosis in the absence of shock were sepsis (49%), liver disease (15%), and respiratory failure (12%). The median survival was 38.5 hours. Survival at 24 hours was 59%. Arterial pH predicted 24-hour survival better than base deficit or bicarbonate level. Percent survival was 41% at 3 days and 17% at 30 days. Only 21% of patients survived to leave the intensive care unit, and 17% were discharged from the hospital. In patients receiving sodium bicarbonate, neither acid-base nor hemodynamic status improved. CONCLUSIONS: In this first prospective study of the clinical course of acute lactic acidosis in adults, nearly all subjects had both hemodynamic and nonhemodynamic (metabolic) underlying causes, many of which independently predicted survival and most of which were refractory to standard care.

Acidosis, Lactic↗
PubMed1998

[A young woman with metabolic acidosis and recently discovered IDDM without ketonuria. A rare autoimmune (?) combination of hypothyroidism, diabetes mellitus and distal renal tubular acidosis].

A case of a 29-year-old woman with a multiple autoimmune disorder is reported. She had a history of hypothyroidism since the age of 18. She was admitted to hospital due to hyperglycaemia. At admission she had hyperglycaemia, metabolic acidosis, but no urinary ketone bodies. Further laboratory studies revealed that the acidosis was due to distal renal tubular acidosis rather than diabetic ketoacidosis (although the patient had type 1 diabetes mellitus). Blood tests revealed antibodies to glutamic acid decarboxylase (GAD-65; associated with type 1 diabetes mellitus), thyroid and adrenal tissue, and gastric parietal cells. The patient had not developed pernicious anaemia or Addison's disease. The multiple positive antibody titres in this patient indicate that the diabetes, hypothyroidism and distal renal tubular acidosis are part of an autoimmune syndrome.

Acidosis, Renal Tubular↗
PubMed1989

Aldosterone secretion during acute respiratory acidosis and NH4Cl-induced metabolic acidosis in the goat.

Acute respiratory acidosis was induced in goats by inhalation of 6% or 8% CO2 in air for 30 min. The lower CO2 concentration caused a significant rise in plasma cortisol (PC), but had no appreciable influence upon plasma aldosterone (PA), and did not affect the arterial blood pressure (aBP). A more pronounced PC response was observed in association with the inhalation of 8% CO2, but also here without concomitant increase in PA. However, the aBP became elevated by about 30% during the CO2 exposure with a simultaneous increase in glomerular filtration rate and a water diuresis, suggesting that the release of arginine vasopressin temporarily became inhibited. It was confirmed that metabolic acidosis induced by duodenal NH4Cl administration is preceded by a transient rise in PA. Dexamethasone-induced feedback inhibition of the ACTH secretion blocked the PA response, which possibly reflects NH4 ion stimulation of the ACTH release. The combined results of the CO2 and NH4Cl experiments seem to justify the conclusion that increases in PA seen in conjunction with acidosis do not reflect a direct hydrogen ion stimulation of the adrenal glomerulosa cells.

Acidosis↗
PubMed1999

Different effects of simple anoxic lactic acidosis and simulated in vivo anoxic acidosis on turtle heart.

We compared responses of turtle heart at 20 degrees C to an anoxic lactic acidosis solution (LA) containing 35 mM lactic acid in an otherwise normal turtle Ringers equilibrated with 3% CO2/97% N2 at pH 7.0) to a solution simulating in vivo anoxic acidosis (VA), with elevated concentrations of lactate, Ca2+, Mg2+, and K+, and decreased Cl-, equilibrated with 10.8% CO2/89.2% N2 at pH 7.0. We examined mechanical properties on cardiac muscle strips and determined intracellular pH (pHi) and high energy phosphates on perfused hearts using 31P-NMR. Maximum active force (Fmax) and the maximum rate of force development (dF/dtmax) of muscle strips were significantly higher during VA than during LA superfusion. An elevation of Ca2+ alone (to 6 mM) in LA significantly increased both Fmax and dF/dtmax but the effects diminished toward the end of the exposure; however, hypercapnic anoxic lactic acidosis (addition of 20 mM HCO3- to LA, equilibrated with 10.8% CO2/89.2% N2, pH 7.0) did not significantly affect Fmax or dF/dtmax. During VA perfusion, pHi (6.73 +/- 0.01) was significantly higher than that during LA perfusion (pHi 6.69 +/- 0.013), but the difference is probably too small to have physiological significance. ATP, creatine phosphate, and inorganic phosphate were not significantly different in the two anoxic solutions. We conclude that the reduction of cardiac mechanical function in vivo is minimized by the integrated effects of changes of ionic concentrations, but the observed changes in Ca2+ and pHi cannot fully explain the effect.

Acidosis, Lactic↗
PubMed1977

Natural history of lactic acidosis after grand-mal seizures. A model for the study of an anion-gap acidosis not associated with hyperkalemia.

To define the time course of the metabolic acidosis that follows a single grand-mal seizure, we obtained serial blood samples from eight consecutive patients. Immediately after a seizure, the mean (+/- S.E.M.) venous lactate concentration was 12.7 +/- 1.0 meq per liter, the mean carbon dioxide content 17.1 +/- 1.1 mmol per liter, and the mean arterial pH 7.14 +/- 0.06. Sixty minutes later their values were 6.6 +/- 0.7 meq per liter (P less than 0.005), 23.6 +/- 1.1 mmol per liter (P less than 0.005) and 7.38 +/- 0.04 (P less than 0.005) respectively. The spontaneous resolution of the acidosis was due, in large part, to the metabolism of lactate and to the concomitant removal of hydrogen ion. There was no change in the serum potassium concentration, despite the development of a severe systemic acidemia and the subsequent return to normal of the pH. We suggest that the patient with seizures may serve as a unique model of lactic acidosis.

Acetates↗
PubMed1992

A controlled clinical trial of dichloroacetate for treatment of lactic acidosis in adults. The Dichloroacetate-Lactic Acidosis Study Group.

BACKGROUND: Mortality is very high in lactic acidosis, and there is no satisfactory treatment other than treatment of the underlying cause. Uncontrolled studies have suggested that dichloroacetate, which stimulates the oxidation of lactate to acetyl-coenzyme A and carbon dioxide, might reduce morbidity and improve survival among patients with this condition. METHODS: We conducted a placebo-controlled, randomized trial of intravenous sodium dichloroacetate therapy in 252 patients with lactic acidosis; 126 were assigned to receive dichloroacetate and 126 to receive placebo. The entry criteria included an arterial-blood lactate concentration of > or = 5.0 mmol per liter and either an arterial-blood pH of < or = 7.35 or a base deficit of > or = 6 mmol per liter. The mean (+/- SD) arterial-blood lactate concentrations before treatment were 11.6 +/- 7.0 mmol per liter in the dichloroacetate-treated patients and 10.4 +/- 5.5 mmol per liter in the placebo group, and the mean initial arterial-blood pH values were 7.24 +/- 0.12 and 7.24 +/- 0.13, respectively. Eighty-six percent of the patients required mechanical ventilation, and 74 percent required pressor agents, inotropic drugs, or both because of hypotension. RESULTS: The arterial-blood lactate concentration decreased 20 percent or more in 83 (66 percent) of the 126 patients who received dichloroacetate and 45 (36 percent) of the 126 patients who received placebo (P = 0.001). The arterial-blood pH also increased more in the dichloroacetate-treated patients (P = 0.005). The absolute magnitude of the differences was small, however, and they were not associated with improvement in hemodynamics or survival. Only 12 percent of the dichloroacetate-treated patients and 17 percent of the placebo patients survived to be discharged from the hospital. CONCLUSIONS: Dichloroacetate treatment of patients with severe lactic acidosis results in statistically significant but clinically unimportant changes in arterial-blood lactate concentrations and pH and fails to alter either hemodynamics or survival.

Acidosis, Lactic↗
PubMedDate not supplied

[Gastric emptying and metabolic acidosis. III. Study of gastric retention of a sodium citrate solution using an experimental model of metabolic acidosis in rats].

The gastric emptying of sodium citrate solution 0.25 mEq/ml was studied in rats with metabolic acidosis induced by orogastric infusion of 0.5 M ammonium chloride solution. Two control groups were used: one infused with 0.5 M sodium chloride and the other with water. The 3 solutions content was 2 ml/100 g weight of the animal. Six hours after the infusion, there was a moderate metabolic acidosis in the group with ammonium citrate. This 6 hour interval marked the beginning of the gastric emptying study. The test meal (sodium citrate 0.25 mEq/ml) was utilized containing 6 mg% red fenol as a marker. The gastric emptying of sodium citrate was studied at 5, 10, 20 and 30 minutes after the infusion, and the results showed no differences between the 3 groups. The data suggest that the duodenal receptors to pH were more effective do determine the pattern of gastric response than the acidosis.

Acid-Base Equilibrium↗
PubMed1985

Attenuation by atenolol of myocardial acidosis during ischemia in dogs: contribution of beta-1 adrenoceptors to myocardial acidosis.

Coronary artery occlusion produces myocardial acidosis, which can be attenuated by propranolol or sotalol. The present study was undertaken to determine which beta adrenoceptors, beta-1 or beta-2, contribute to the ischemic myocardial acidosis. Dogs anesthetized with pentobarbital were used. In the first series of experiments, blood flow in the left anterior descending coronary artery was reduced by an occluder to about one-third of the original flow. Myocardial pH was measured by means of a micro pH electrode inserted into the left anterior descending coronary artery area at the depth of about 8 mm. The myocardial pH decreased from 7.44 to 7.55 to 6.73 to 6.89, 30 min after partial occlusion being the time immediately before an i.v. injection of drugs. Atenolol (1 mg/kg) attenuated significantly the decrease in myocardial pH that had been induced by partial occlusion, whereas IPS 339 (360 micrograms/kg) and ICI 118,551 (300 micrograms/kg) did not. The pH effect of atenolol was confirmed even in the paced heart. In the second series of experiments, the antagonistic action of these drugs on the isoproterenol-induced increase in heart rate and myocardial contractile force and the decrease in diastolic blood pressure was investigated. By this experiment, it was confirmed that atenolol has the beta-1 adrenoceptor antagonistic action, and the IPS 339 and ICI 118,551 have the beta-2 antagonistic action. These results suggest that the activation of beta-1 adrenoceptors contribute to the myocardial acidosis during ischemia.

Acidosis↗
PubMed1988

"Cerebral" lactic acidosis: defects in pyruvate metabolism with profound brain damage and minimal systemic acidosis.

Six patients are described with a combination of early onset of neurological symptoms, gross cerebral changes and elevated concentrations of pyruvate and lactate in cerebrospinal fluid. Although at least five of the six patients appear to have a generalised defect in pyruvate metabolism, reflected in deficient pyruvate dehydrogenase activity in cultured fibroblasts, systemic acidosis was not a problem clinically and blood pyruvate and lactate concentrations were only slightly raised. The localisation of significant clinical and biochemical problems to the central nervous system, coupled with the difficulties in making the diagnosis if analysis of cerebrospinal fluid (CSF) is not performed, lead us to term this condition "cerebral" lactic acidosis.

Acidosis, Lactic↗
PubMed1981

[Comparison of the effects of acute respiratory acidosis and acute metabolic acidosis on the jaw-opening reflex in the anesthetized dog].

A few effects of carbon dioxide on pain threshold and acid-base balance are known. The purpose of this study was to investigate specifically the variations of analgesia in relation to hypercapnia during general anaesthesia and the respective roles played by carbon dioxide and [H+]. The nociceptive jaw opening reflex was studied on five beagle dogs anaesthetized with alfathesin administered at constant rate under acute hypercapnic conditions and acute metabolic acidosis. Acute hypercapnia did not decrease the jaw opening reflex significantly until a level was reached where PaCO2 values modified blood [H+] (pH) significantly (10 +/- 1.04 kPa corresponding to [H+] 91.5 +/- 13.24 nmol/l (pH 7.04 +/- 0.06) p less than 0.05)). At [H+] 176.2 +/- 42.77 nmol/l (pH 6.7 +/- 0.13) (p less than 0.01) the reflex was only 9.3 +/- 3.9 per cent (p less than 0.001) of its initial value. The infusion of decinormal solution of HCl during constant capnia caused an abrupt drop of the reflex. There was a correlation between reflex and metabolic acidosis (p less than 0.05). The authors conclude that modification of the jaw opening reflex occurs with extreme values of arterial [H+] incompatible with safe anaesthesia and they discuss the mechanisms involved.

Acidosis, Respiratory↗
PubMed2001

Oedema disease is associated with metabolic acidosis and small intestinal acidosis.

Limited information is available about the pathogenesis and pathophysiology of oedema disease (OD). Oedema disease is caused by specific enterotoxemic Escherichia coli (SLTIIv-toxin producing) strains; however, the same strains are also found in non-afflicted pigs. Furthermore, it is unclear how the 80 kDa SLTIIv-toxin can pass the intestinal barrier. In the present paper, piglets showing signs of acute OD were anaesthetised, instrumented and cardiovascular and intestinal parameters were determined at 0, 1, 2 and 3 hours. Healthy piglets from the same herd were used as a control. Cardiac output, blood pH and bicarbonate, small intestinal intramucosal pH, and (pulmonary) blood pressure were significantly lower in OD-pigs than in control pigs. It is concluded that OD is associated with metabolic and intestinal acidosis. Intestinal acidosis is known to increase macromolecular permeability. This suggests that once OD has developed, influx of SLTIIv-toxin into the blood stream is facilitated, thus perpetuating the disease. Since intestinal permeability appears to be central in OD, it is argued that post-weaning events increase intestinal permeability and predispose individuals to OD.

Acidosis↗
PubMed1998

Response of intra-acinar pulmonary microvessels to hypoxia, hypercapnic acidosis, and isocapnic acidosis.

To elucidate the differential reactivity of pulmonary microvessels in the acini to hypoxia, excessive CO2, and increased H+, we investigated changes in the diameter of precapillary arterioles, postcapillary venules, and capillaries in isolated rat lungs on exposure to normocapnic hypoxia (2% O2), normoxic hypercapnia (15% CO2), and isocapnic acidosis (0.01 mol/L HCl). Microvascular diameters were precisely examined using a real-time confocal laser scanning luminescence microscope coupled to a high-sensitivity camera with an image intensifier. Measurements were made under conditions with and without indomethacin or N(omega)-nitro-L-arginine methyl ester to assess the importance of vasoactive substances produced by cyclooxygenase (COX) or NO synthase (NOS) as it relates to the reactivity of pulmonary microvessels to physiological stimuli. We found that acute hypoxia contracted precapillary arterioles that had diameters of 20 to 30 microm but did not constrict postcapillary venules of similar size. COX- and NOS-related vasoactive substances did not modulate hypoxia-elicited arteriolar constriction. Hypercapnia induced a distinct venular dilatation closely associated with vasodilators produced by COX but not by NOS. Arterioles were appreciably constricted in isocapnic acidosis when NOS, but not COX, was suppressed, whereas venules showed no constrictive response even when both enzymes were inhibited. Capillaries were neither constricted nor dilated under any experimental conditions. These findings suggest that reactivity to hypoxia, CO2, and H+ is not qualitatively similar among intra-acinar microvessels, in which COX- and NOS-associated vasoactive substances function differently.

6-Ketoprostaglandin F1 alpha↗
PubMed1980

The genetic heterogeneity of lactic acidosis: occurrence of recognizable inborn errors of metabolism in pediatric population with lactic acidosis.

A total of 40 skin fibroblast cultures from pediatric cases of lactic acidosis were subjected to a series of tests designed to elucidate the nature of an underlying defect in metabolism. Of these 40 cases, in 14 we were able to define the following problems. Pyruvate carboxylase deficiency was evident in five cases showing < 10% normal activity. Phosphoenolpyruvate carboxykinase deficiency was evident in one case where the whole cells showed 17% of normal activity whereas the mitochondrial activity of this enzyme was 6% of normal. Pyruvate dehydrogenase deficiency was present in six cases showing 8 to 39% of normal activity, five of them being due to deficient pyruvate decarboxylase activity and one of them being due to deficient dihydrolipoyl dehydrogenase activity. Two cases were found with normal enzymes of pyruvate metabolism in which the production of 14CO2 from [3-14C]pyruvate was deficient at 13 and 28% of normal activity, respectively, which we consider to be indicative of reduced activity of the Krebs' cycle. The grounds for the diagnosis of these 14 affected cases are documented, and the clinical presentation of these enzyme deficiencies is assessed in the light of present knowledge about lactic acidosis.

Acidosis↗
PubMed1991

[Hyperchloremic acidosis in metabolic acidosis with anion gap excess. Comparison with diabetic ketoacidosis].

The occurrence of hyperchloremia during diabetic ketoacidosis (DKA) recovery and the lack of correlation between anion gap excess (delta AG) and bicarbonate deficit (delta TCO2) on admission suggest an hyperchloremic acidosis (HCLA) component. The hypothesis that this phenomenon is not specific of DKA and can occur in other metabolic acidoses with increased anion gap was tested. HCLA component, defined by the ratio delta AG/delta TCO2 less than or equal to 0.80, was evaluated on admission and during therapy in 31 patients with DKA and 53 patients with non diabetic metabolic acidosis (ND-MA). HCLA component prevalence was similar on admission (32 p. 100 for DKA versus 41 p. 100 for ND-MA), but it increased during therapy only in DKA patients (86 p. 100 at 9 h - P less than 0.001). In view of the significant correlation (r = 0.636; P less than 0.001) observed between delta AG/delta TCO2 and creatinine, kidney acid base defense appears clearly in DKA patients: the more severe the volume depletion, the greater the ketone retention and the less prominent the HCLA. This phenomenon seems to be secondary to a large tubular excretion of ketones. In the 53 ND-MA patients no correlation between delta AG/delta TCO2 and creatinine could be found. A transfer of chloride from cells to the extracellular space secondary to intracellular diffusion of lactate ions could explain the HCLA component.

Acid-Base Equilibrium↗
PubMed1977

[Clinical picture of lactate acidosis. 4: Clinical significance of lactate acidosis].

The diagnosis of lactate acidosis is complicated by the fact that lactate determination is not a routine method in clinical chemistry. In fact, lactate analysis is performed only in special laboratories. Even in greater clinics this method is not routinely performed in differential diagnosis of acidotic states. Various diseases are accompanied by a lactate emia or even by lactate acidosis. Anaerobic synthesis of lactate is an emergency reaction to supply minimum energy to tissues with insufficient oxygen supply. The main diseases complicated by increased blood lactate concentrations are shock, circulatory collapse, cardiac failure and peripheral circularoty disturbance. Additionally diabetes mellitus, septical infections, and-the most prominent situation-biguanide intoxications are complicated by an increase in blood lactate concentration.

Acidosis↗
PubMed1977

[The clinical picture of lactate acidosis. 5. Lactatemia without acidosis. Conclusions].

Several inherited metabolic diseases are accompanied by a greater or lesser increase in blood lactate concentration under certain metabolic conditions. These diseases are glycogenosis type I (glocuse-6-phosphate deficiency), fructose-1,6-diphosphatase deficiency, glucose-induced hyperlactate emia, idiopathic lactate acidosis. The conditions are discussed when hyperlactate emia develops. Very large increases in blood lactate concentration are found during muscular activity, lactate concentrations can be as much as 20 mmol/l under these conditions. Regarding these values, the increase in blood lactate concentration during intravenous carbohydrate infusion is minimum, even in the case of fructose infusions (1-4 mmol/l). Therapeutical measures for treatment of increased lactate concentration are discussed. A causal therapy is optimum; however, the precondition is a definite diagnosis. Besides bicarbonate infusions (or infusions of other alkalizing substances) dialysis seems to be a favourable therapy in certain cases. In future, prognosis of lactate emia should be better if the diagnostic measures and differential diagnosis are improved.

Acidosis↗