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PubMed1989

Phospholipid changes during adaptation to acidosis in urinary bladder of Bufo marinus.

The purpose of this study was to determine whether phospholipids (PL) play a role in the adaptation to metabolic acidosis by toad urinary bladder epithelium. Toads were placed in an NH4Cl acidosis for 48 hr. Quarter bladders were removed and incubated with [32P]orthophosphate or [3H]arachidonic acid for 1 hr at 25 degrees C. PL were detected by thin layer chromatography, autoradiography, and quantitated by liquid scintillation counting or fractional amounts were determined from phosphate content and expressed as counts per minute per micromolar of total phosphate or as percentage of fraction of total PL. Incorporation of [3H]arachidonic acid into urinary bladder PL was measured in acidotic and normal toads. There was a higher rate of arachidonic acid incorporation into several PL in acidotic animals. Phosphatidic acid and phosphatidylserine fraction in acidosis was 37,705 +/- 6,821 and in normal bladders was 9,254 +/- 2,652 (P less than 0.005); phosphatidylcholine fraction in acidotic toads was 80,462 +/- 16,862 and in normal bladders was 26,892 +/- 5,198 (P less than 0.025); and the phosphatidylethanolamine (PE) fraction in acidotic was 48,665 +/- 10,998 and in normal animals was 17,441 +/- 3,905 (P less than 0.025). 32P labeling revealed a higher rate of incorporation in bladders from acidotic toads compared with normal toads. In the acidotic bladders, the phosphatidic acid and phosphatidylserine fraction was 19,754 +/- 3,597 and in normal bladders was 12,980 +/- 1,394 (P less than 0.05) and for PE acidotic bladders was 9,129 +/- 1,304 and in normal bladders was 3,285 +/- 416 (P less than 0.001). Fractional PL (reported as percentage of fraction of total PL based on total lipid phosphorus) analysis in normal toads revealed phosphatidylinositol = 8.1 +/- 0.6% and PE = 27 +/- 1.2%, whereas for acidotic toads phosphatidylinositol = 11 +/- 0.6% and PE = 32 +/- 1.0% (P less than 0.01 for both). Aldosterone, a known stimulator of acidification, had no effect on 32P incorporation into PL fractions of the bladder. The increase in PL turnover following induction of acidosis is consistent with increased membrane synthesis or turnover during metabolic acidosis and this may reflect an increased transport of vesicular H+-ATPase into the apical membrane or the result of a proliferation of acid-secreting mitochondria-rich cells or both.

Acidosis↗
PubMed2004

Acidosis improves uptake of antigens and MHC class I-restricted presentation by dendritic cells.

It is widely appreciated that inflammatory responses in peripheral tissues are usually associated to the development of acidic microenvironments. Despite this, there are few studies aimed to analyze the effect of extracellular pH on immune cell functions. We analyzed the impact of acidosis on the behavior of dendritic cells (DCs) derived from murine bone marrow. We found that extracellular acidosis (pH 6.5) markedly stimulated the uptake of FITC-OVA, FITC-dextran, and HRP by DCs. In fact, to reach similar levels of endocytosis, DCs cultured at pH 7.3 required concentrations of Ag in the extracellular medium almost 10-fold higher compared with DCs cultured at pH 6.5. Not only the endocytic capacity of DCs was up-regulated by extracellular acidosis, but also the expression of CD11c, MHC class II, CD40, and CD86 as well as the acquisition of extracellular Ags by DCs for MHC class I-restricted presentation. Importantly, DCs pulsed with Ag under acidosis showed an improved efficacy to induce both specific CD8(+) CTLs and specific Ab responses in vivo. Our results suggest that extracellular acidosis improves the Ag-presenting capacity of DCs.

Acidosis↗
PubMed1977

Phenformin-associated lactic acidosis: pathogenesis and treatment.

Since phenformin's introduction into clinical medicine, a total of 552 cases of lactic acidosis have been reported in patients taking this hypoglycemic agent. In 306 cases, sufficient documentation was available to establish the diagnosis with reasonable certainty (blood lactate, 6 meq/litre or greater, and blood pH, 7.33 or less). The mortality rate among insulin-treated patients (15%) was considerably less than the mortality rate in the group as a whole (42%). Taken together with results from animal studies, these data suggest that insulin is the treatment of choice for phenformin-associated lactic acidosis. Sodium bicarbonate should be administered to patients with severe acidosis, but should be withheld from patients with mild acidosis. Overly aggressive administration of sodium bicarbonate can be deleterious and should be avoided. Although dialysis has been suggested by some authors for the treatment of phenformin-associated lactic acidosis, the mortality rate among dialyzed patients (48%) was roughly the same as for the group as a whole (42%).

Acidosis↗
PubMed1983

D-Lactic acidosis after jejunoileal bypass: identification of organic anions by nuclear magnetic resonance spectroscopy.

A 40-year-old man with jejunoileal bypass developed a syndrome of bizarre behavior, slurred speech, ataxic gait, and inappropriate affect, associated with a metabolic acidosis characterized by an increase in the anion gap. Serum L-lactate level was normal, but high-resolution proton nuclear magnetic resonance spectrums of the patient's serum showed a high concentration of lactate. A diagnosis of D-lactic acidosis was confirmed by a specific enzymatic assay for D-lactate. The D-lactic acidosis was cleared using antibiotic therapy, suggesting that D-lactate is produced from fermentation of ingested carbohydrate by colonic bacteria. Nuclear magnetic resonance spectroscopy is a rapid screening test for identifying organic acids in patients with unexplained acidosis. Neuropsychiatric symptoms in patients with short bowel syndrome may be associated with D-lactic acidosis.

Acid-Base Equilibrium↗
PubMed1992

The efficacy of Doppler umbilical artery velocimetry in identifying fetal acidosis. A comparison with fetal biophysical profile.

In 105 singleton pregnancies in which cesarean section was performed before the onset of labor, the efficacy of Doppler umbilical velocimetry in identifying fetal acidosis was determined and compared with fetal biophysical profile. Doppler velocimetry showed a significant correlation with the umbilical artery pH and was also a sensitive indicator of fetal acidosis, comparable to the biophysical profile score. Patients were classified into four groups. Groups with abnormal Doppler results showed a significantly higher prevalence of fetal acidosis, and all the fetuses with abnormal Doppler results were either in acidosis or in a growth-retarded state. Our data lend further support to the clinical validity of Doppler umbilical velocimetry in identifying fetal acidosis or compromise.

Acidosis↗
PubMed1999

Metabolic acidosis-induced retinopathy in the neonatal rat.

PURPOSE: Carbon dioxide (CO2)-induced retinopathy (CDIR) in the neonatal rat, analogous to human retinopathy of prematurity (ROP), was previously described by our group. In this model, it is possible that CO2-associated acidosis provides a biochemical mechanism for CDIR. Therefore, the effect of pure metabolic acidosis on the developing retinal vasculature of the neonatal rat was investigated. METHODS: A preliminary study of arterial blood pH was performed to confirm acidosis in our model. In neonatal rats with preplaced left carotid artery catheters, acute blood gas samples were taken 1 to 24 hours after gavage with either NH4Cl 1 millimole/100 g body weight or saline. In the subsequent formal retinopathy study, 150 newborn Sprague-Dawley rats were raised in litters of 25 and randomly assigned to be gavaged twice daily with either NH4Cl 1 millimole/100 g body weight (n = 75) or saline (n = 75) from day 2 to day 7. After 5 days of recovery, rats were killed, and retinal vasculature was assessed using fluorescein perfusion and ADPase staining techniques. RESULTS: In the preliminary pH study, the minimum pH after NH4Cl gavage was 7.10+/-0.10 at 3 hours (versus 7.37+/-0.03 in controls, mean +/- SD, P < 0.01). In the formal retinopathy study, preretinal neovascularization occurred in 36% of acidotic rats versus 5% of controls (P < 0.001). Acidotic rats showed growth retardation (final weight 16.5+/-3.0 g versus 20.2+/-2.6 g, P < 0.001). The ratio of vascularized to total retinal area was smaller in acidotic rats (94%+/-4% versus 96%+/-2%, P < 0.001). CONCLUSIONS: Metabolic acidosis alone induces neovascularization similar to ROP in the neonatal rat. This suggests a possible biochemical mechanism by which high levels of CO2 induce neovascularization and supports the suggestion that acidosis may be an independent risk factor for ROP.

Acidosis↗
PubMed1999

Effects of acidosis on leptin secretion from 3T3-L1 adipocytes and on serum leptin in the uraemic rat.

Marked hyperleptinaemia and metabolic acidosis are common findings in patients with chronic renal failure. In animal models, both leptin administration and acidosis reduce food intake. However, leptin causes loss of body fat, while acidosis induces muscle wasting. Whether a low pH and leptin production are related has not been studied. Leptin secretion was measured in cultured 3T3-L1 adipocytes exposed to acid or control pH for up to 96 h. In addition, serum leptin was compared between acidotic and bicarbonate-treated uraemic Wistar rats using the remnant model. Leptin levels in the culture medium were decreased at an acid pH of 7.1 compared with a control pH of 7.5 at 96 h (562+/-78 and 831+/-103 pg.48 h(-1). well(-1) respectively; mean+/-S.E.M.; P=0.037). Similarly, serum leptin in uraemic rats was found to be lower in the acidotic group than in the bicarbonate-treated group, although this observation fell just short of statistical significance (1273+/-171 compared with 2059+/-376 pg/ml; P=0.07). In conclusion, acidosis decreases leptin secretion from cultured adipocytes. Accordingly, acidotic uraemic rats seem to exhibit lower serum leptin levels than their bicarbonate-supplemented counterparts. This study is the first report providing a link between acidosis and leptin levels.

3T3 Cells↗
PubMed2000

[Significance of respiratory compensation in acidosis in calves].

The respiratory component PvCO2 of acid-base-status was observed in n = 36 calves (age: x +/- s = 8.7 +/- 5.0 d) with neonatal diarrhea and an acidosis (venous blood-pH: < 7.30; x +/- s = 7.08 +/- 0.15). In n = 10 (28%) calves with a severe metabolic acidosis (pH: x +/- s = 7.03 +/- 0.12; BE: x +/- s = -22.1 +/- 5.3 mmol/l) the PvCO2 was decreased < 5.3 kPa (x +/- s = 4.5 +/- 0.5 kPa) and showed a distinct respiratory compensation. A PvCO2 between 5.3-6.7 kPa (x +/- s = 6.0 +/- 0.4 kPa) was observed in n = 16 (44%) acidotic calves (pH: x +/- s = 7.11 +/- 0.13; BE: x +/- s = -15.2 +/- 7.4 mmol/l). These n = 26 (72%) calves showed a simple metabolic acidosis which is well known for calves with neonatal diarrhea. The remaining n = 10 (28%) calves showed an increase of the PvCO2 > 6.7 kPa (x +/- s = 8.0 +/- 1.5 kPa). These animals had a mixed respiratory-metabolic acidosis (pH: x +/- s = 7.08 +/- 0.20; BE: x +/- s = -13.9 +/- 10.3 mmol/l), as the decrease of the pH could not be determined by the decreased metabolic component HCO3- of acid-base-status alone. Calves which died during hospitalization and calves with a PvCO2 > 6.7 kPa tended to be younger and showed partially significant lower values for the parameters of oxygen-supply PvO2 and SvO2. Lactate was significantly higher in dying calves but not in calves with a mixed acidosis which on the other hand were more dehydrated. The functional capacity of respiratory compensation of acidotic disorders in the calves studied promised to be almost the same as in dog and man. One reason for the failure of respiratory compensation in some calves could be a more severe hypovolemia. With the use of "venous hypoxemia" (decrease PvO2 and decrease SvO2) the detection of tissue hypoxia was easier than with lactate concentration.

Acidosis↗
PubMed2001

Metformin-associated lactic acidosis in a low risk patient.

Metformin is an oral hypoglycemic agent belonging to the class of biguanides that are commonly used in the treatment of type II diabetes mellitus. Lactic acidosis is a rare but severe adverse reaction that occurs primarily in patients with contraindications such as renal failure. The case of a 71-year-old woman with type II diabetes, in whom severe metformin-associated lactic acidosis was precipitated by acute renal failure in the absence of pre-existing chronic renal failure or other absolute contraindications to biguanide use, is presented. Aggressive correction of the acidosis and prolonged dialysis resulted in a favourable outcome despite severe acidosis. The present case report shows that metformin-associated lactic acidosis can occur in patients without pre-existing renal insufficiency. Metformin should be temporarily stopped when acute renal failure occurs or is anticipated.

Acidosis, Lactic↗
PubMed2002

[Recurrent episodes of acidosis with encephalopathy in a hemodialysis program patient with short bowel syndrome].

We present a case of a patient with short bowel syndrome in a hemodialysis program, with recurrent episodes of serious acidosis. The presence of a D-lactic acidosis peak secondary to bacterial overgrowth in the intestine was discovered during an acute episode of acidosis, with neurological affection. The detection of acidosis in predialysis measurements and the acute episodes of acidosis, made it necessary to administer bicarbonate to the patient and give him additional hemodialysis sessions.

Acidosis, Lactic↗
PubMed1992

Roles of hormones in plasma potassium alteration in acute respiratory acidosis in dogs.

The present study was conducted to examine the roles of hormonal factors in plasma potassium alterations in acute respiratory acidosis. Respiratory acidosis (pH, 7.07-7.10) induced by the inhalation of 10% CO2, 20% O2 and 70% N2 mixed gas caused an increase in the plasma potassium concentration beyond that of the control of 3.44 +/- 0.12 (mean +/- SE) to 4.36 +/- 0.07 mEq/l (p less than 0.01) within 180 min. The plasma norepinephrine concentration was also noted to significantly increase at the same time. Phentolamine (40 micrograms/kg/min i.v.) did not affect the degree of acidosis or acidosis-induced hyperkalemia. No significant changes in the plasma levels of epinephrine, insulin, glucagon, cortisol or aldosterone could be detected. Hormonal factors would thus appear not to be essential to potassium movement from intracellular to extracellular compartments in acute respiratory acidosis.

Acidosis, Respiratory↗
PubMed2003

[Association of distal tubular acidosis, Hashimoto's thyroiditis and Gougerot-Sjögren's syndrome].

INTRODUCTION: Distal tubular acidosis is associated with auto-immune diseases not specific to organ. The coexistence of distal tubular acidosis and auto-immune thyroid affection is very rare. OBSERVATION: A 36-year-old woman exhibiting primary hypothyroidism, Gougerot-Sjögren's syndrome and hypergammaglobulinemia, presented distal tubular acidosis revealed by severe hypokaliemia and complicated by quadriplegia and circulatory arrest. Correcting the thyroid defect did not appear to influence the progression of acidosis. COMMENTS: Based on this observation, one can discuss the pathogenesis of distal tubular acidosis during auto-immune diseases (hypothyroidism, Gougerot-Sjögren's syndrome and monoclonal hypergammaglobulinemia) and its impact on therapy.

Acidosis, Renal Tubular↗
PubMed1992

Mechanisms for protein catabolism in uremia: metabolic acidosis and activation of proteolytic pathways.

Accelerated protein catabolism in uremia occurs in animals and patients with acute (ARF) and chronic renal failure (CRF). Possible causes include resistance to both insulin-induced inhibition of protein-degradation and insulin-induced stimulation of protein synthesis. The mechanisms for these effects are unknown. However, metabolic acidosis has been shown to increase proteolysis in rat skeletal muscle even in the presence of insulin and this effect is absent in adrenalectomized rats. Similarly, metabolic acidosis accounts for increased muscle proteolysis in rats with CRF. Metabolic acidosis also stimulates branched-chain amino acid (BCAA) breakdown by increasing the activity of branched-chain keto acid decarboxylase. Uremia causes high corticosterone levels in ARF and CRF and this hormone could contribute significantly to increased proteolysis, BCAA-breakdown and possibly, the inhibition of protein synthesis. Besides changing glucocorticoids, uremia could inhibit the activity of transporters which regulate intracellular pH and ultimately, the metabolism of protein and amino acids. For example, uremia inhibits ion transporters including Na/H exchange in a variety of tissues and therefore, could increase the susceptibility to metabolic acidosis. Research directed at identifying specific, proteolytic pathways stimulated by metabolic acidosis has excluded a major role for Ca2+ activated and lysosomal proteases and suggests activation of an ATP- and ubiquitin-dependent proteolytic pathway.

Acidosis↗
PubMed2004

[The short term prognosis in alcoholic liver disease with metabolic acidosis].

BACKGROUND/AIMS: Alcoholic liver disease with metabolic acidosis may have possible causes such as alcoholic ketoacidosis, diabetic ketoacidosis, lactic acidosis. Salicylate, methanol, and ethylene glycol intoxication should also be considered. The aim of this study was to investigate the short-term prognostic factors in patients with alcoholic liver disease with metabolic acidosis. METHODS: Clinical data related to twenty-nine patients with alcoholic liver disease and metabolic acidosis was analysed retrospectively. Patients were divided into two groups according to the outcome (survival or death). Past medical history, and physical, laboratory and radiologic data at admission were compared. RESULTS: The amount of daily alcohol intake differed significantly between the two groups (P=0.034), but duration and total amount of alcohol intake did not differ significantly between the two groups (P=0.128; P=0.360). The presence of ascites differed significantly between two the groups (P=0.019). On laboratory testing, the following differed significantly: base excess (P=0.038), hemoglobin (P=0.019), platelet (P=0.040), total bilirubin (P=0.007), albumin (P=0.012), creatinine (P=0.014), phosphorus (P=0.021), chloride (P=0.010), ammonia (P=0.003), prothrombin time (P=0.033), fibrinogen (P=0.011) and D-dimer (P=0.024). Review of the medical history of the patients showed diabetes (10/29), cirrhosis (10/29), and hepatocellular carcinoma (1/29). Combined conditions at admission were sepsis (8/29), pneumonia (7/29), acute renal failure (6/29), rhabdomyolysis (5/29), gastrointestinal hemorrhage (4/29), acute pancreatitis (3/29), acute respiratory distress syndrome (2/29), and acute myocardial infarction (1/29). CONCLUSIONS: The amount of daily alcohol intake, base excess, hemoglobin, platelet, total bilirubin, albumin, creatinine, phosphorus, chloride, ammonia, prothrombin time, fibrinogen and D-dimer seemed to be useful parameters in predicting short-term prognosis of patients with alcoholic liver disease with metabolic acidosis. Further study is needed to define the significance of these factors.

Acidosis↗
PubMed2005

[Metabolic acidosis after kidney transplantation].

Metabolic acidosis is a common complication in patients after kidney transplantation. It is caused by inability of transplanted kidney to regenerate bicarbonate buffer. Although every type of acidosis may be present in these patients, the most frequent are renal tubular acidosis and uremic acidosis. Both insufficiency of graft and tubular dysfunction can be caused by ischemic damage, episodes of rejection and cyclosporine A--induced nephrotoxicity. Ketoacidosis due to a post-transplant diabetes mellitus and bicarbonate loss in patients after simultaneous pancreas/kidney transplantation are rarely observed. Each type of acidosis is responsible for serious metabolic disturbances that influence graft and patient survival. The proper diagnosis and appropriate treatment with oral supplements are essential.

Acidosis, Renal Tubular↗
PubMedDate not supplied

An improved approach to the patient with metabolic acidosis: a need for four amendments.

Clinicians should identify life-threatening issues in patients with metabolic acidosis. These threats may be present before therapy begins and/or anticipated after therapy commences. By adding four amendments, short-comings in the commonly used clinical approaches for the diagnosis of metabolic acidosis can be overcome. First, a definition of metabolic acidosis should consider not only the concentration of bicarbonate but also the content of bicarbonate in the extra cellular fluid compartment. The latter requires a quantitative estimate of the ECF volume, which can be obtained using the hematocrit and/or the total protein concentration in plasma. Second, to determine if the basis for metabolic acidosis was the addition of acids or the loss of NaHCO 3 , one must hunt for new anions, not only in plasma, but also in the urine. Third, it is important to measure the venous as well as the arterial PCO2 to assess the capacity to buffer H+ while minimizing H + binding to intracellular proteins. Fourth, to assess the role of the kidney in a patient with metabolic acidosis, the urine osmolal gap and the concentration of creatinine in the urine should be measured to provide an estimate of the rate of excretion of ammonium.

Acid-Base Equilibrium↗
PubMed2006

[Two patients with lactic acidosis and hypoglycaemia as initial presentation of a lymphoma].

A 32-year-old man who had undergone kidney transplantation presented with malaise, severe diarrhoea, nausea and vomiting, productive cough and shortness of breath. A 42-year-old woman with no relevant medical history presented with fever, weight loss and abdominal pain. Both patients had lactic acidosis and hypoglycaemia. Initially, the hyperlactataemia was thought to result from tissue hypoxia (sepsis) but it persisted after correction of the hypovolaemia; therefore, alternative causes were considered. Both patients were found to have T-cell lymphoma with liver infiltration. The male patient died before treatment could be initiated. The lactic acidosis resolved in the female patient following lymphoma treatment, but she died subsequently from the lymphoma. Lymphoreticular malignancies should be considered for cases of lactic acidosis with sufficient oxygen supply, particularly when hypoglycaemia is also present. The lactic acidosis and hypoglycaemia result from increased anaerobic glycolysis in tumour cells. Tumour reduction with chemotherapy can reduce the lactic acidosis.

Acidosis, Lactic↗
PubMed1976

Lactic acidosis in childhood.

Children with chronic metabolic acidosis should be investigated to determine the presence of an organic acid, especially when the plasma electrolyte profile shows a deficiency of anion. One of the organic acids that should be looked for in such a patient is lactic acid. Lactic acidosis due to tissue hypoxia is a well-known phenomenon (e.g., in shock and cardiopulmonary disease) and has not been discussed in this essay; nor has lactic acidosis due to exogenous causes like infusion of fructose or sorbitol, or admiministration of phenformin. Chronic lactic acidosis in infancy is a rare condition. It may be associated with glycogen storage disease Type 1, fructose diphosphatase deficiency, methylmalonic acidemia, propionic acidemia, pyruvate carboxylase or dehydrogenase deficiency and Leigh's subacute necrotizing encephalomyelopathy (SNE). Some patients with chronic lactic acidosis do not have nay of these diseases and comprise an "idiopathic" group. This is a heterogeneous group, probably having several different causes for the metabolic error. In Leigh's SNE, a metabolic block in the formation of thiamine triphosphate in brain has been demonstrated and has been attributed to the presence of an inhibitor of thiamine pyrophosphate-adenosine triphosphate (TPP-ATP) phosphoryl transferase in body fluids. The inhibitor has also been encountered in cases of intermittent cerebellar ataxia and of primary hypoventilation (Ondine's curse), which may represent variants of Leigh's disease. Increased blood levels of lactate, pyruvate and alanine frequently are encountered in SNE, but it still is not clear whether they are due to a primary or secondary disturbance in the catabolism of pyruvate. Disturbed lactate and pyruvate metabolism has also been encountered in isolated cases of mental retardation and growth failure, in mitochondrial myopathies and in polyneuropathies, and may be expected to occur in Wernicke's encephalopathy. Finally, it has been noted in malignancy and in association with other rare metabolic disorders.

Acidosis↗