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PubMed1991

Nuclear magnetic resonance spectroscopy in patients with anion-gap acidosis.

Proton nuclear magnetic resonance spectroscopy was performed on blood or urine from five patients with an anion-gap metabolic acidosis. In all of these cases, this methodology allowed the rapid and specific diagnosis of the nature of the metabolic acidosis. In several of these patients, spectroscopic evidence for intoxication with toxic alcohols was obtained. On the basis of these preliminary data, proton nuclear magnetic resonance spectroscopy may be a useful technique in the evaluation of patients with anion-gap acidosis.

Acid-Base Equilibrium↗
PubMed1993

Normalization of uremic acidosis in hemodialysis patients with a high bicarbonate dialysate.

Uremic acidosis accompanies chronic renal failure in hemodialysis patients because of a retention of nonvolatile acids. Standard bicarbonate (39 mEq/L) and acetate (38 mEq/L) dialysates do not completely correct the acidosis. The acid-base and biochemical effect of a high-bicarbonate (42 mEq/L) dialysate was evaluated in 38 patients during high-efficiency and high-flux dialysis over 12 wk. All patients were dialyzed on standard bicarbonate dialysate before the study and for 8 wk after the study. In order to monitor potential excessive alkalosis, predialysis and postdialysis arterial blood gases were measured in seven patients who initially had a normal predialysis pH. Serum chemistries revealed no significant changes in predialysis BUN, calcium, ionized calcium, or phosphorus during the 12-wk study. There was no change in postdialysis ionized calcium or phosphorus. Predialysis and postdialysis serum total CO2 (STCO2) increased over the 12-wk study (P < 0.0001). By week 12, 75% of the hemodialysis patients had an STCO2 > 23 mEq/L and no patient had an STCO2 > 30 mEq/L predialysis. After the 8-wk washout, all chemistries were no different from prestudy concentrations. Predialysis blood gases in seven patients with normal predialysis HCO3 revealed a significant increase (P < 0.009) in PCO2 and HCO3 over the 12-wk study; predialysis pH and PO2 did not change. There was no significant change in postdialysis blood gases. It was concluded that: (1) a high-bicarbonate dialysate corrects predialysis acidosis in 75% of hemodialysis patients without causing progressive alkalemia, hypoxia, or hypercarbia; and (2) predialysis BUN, calcium, ionized calcium, and phosphorus are unaffected by high-bicarbonate dialysate.

Acidosis↗
PubMed1993

Impaired urinary ammonium excretion in patients with isolated proximal renal tubular acidosis.

During previous studies in patients with isolated proximal renal tubular acidosis (pRTA), the rates of urinary ammonium excretion were considered inappropriately low for their state of chronic metabolic acidosis. These observations were made while the patients were on a normal diet as well as when they were undergoing a short ammonium chloride test. Because these findings suggested an impaired ability to excrete maximal amounts of ammonium, the response to the 3-day acid loading test was evaluated in eight patients with isolated pRTA and in 10 normal control subjects. Plasma creatinine, acid-base, and electrolyte values were analyzed before and after 3 days of ingesting 2 mmol/kg.24 h of ammonium chloride. Twenty-four-hour urine specimens were collected the day before and on the third day of acid loading to determine urine pH, as well as the rate of excretion of NH4+ and titratable acid in milliequivalents per 24 h per 1.73 m2. During the basal state, all patients with pRTA had hyperchloremic metabolic acidosis and they excreted urine of lower pH (5.51 +/- 0.18 versus 6.00 +/- 0.13; P < 0.05) and greater titratable acid (29.1 +/- 4.3 versus 21.8 +/- 1.4; P < 0.05); however, they had rates of NH4+ excretion similar to those of controls. On the third day of acid loading, they excreted urine of lower pH (4.66 +/- 0.03 versus 5.00 +/- 0.03; P < 0.05) and equivalent amounts of titratable acid, whereas their NH4+ excretion was significantly less than that of controls (47.7 +/- 4.4 versus 76.3 +/- 5.7; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1993

Role of protein kinase C in the adaptive increase in Na-H antiporter in respiratory acidosis.

Chronic respiratory acidosis stimulates the Vmax of the renal brush border Na-H antiporter. The activation of protein kinase C (PKC) by phorbol esters stimulates the activity of the renal Na-H antiporter. In this study, the hypothesis that PKC plays a role in the adaptive increase of the renal brush border Na-H antiporter activity to respiratory acidosis was tested. In vivo respiratory acidosis was associated with an increase in in vitro Na-H antiporter activity and also with an increase in brush border membrane PKC activity, without changes in PKC activity in cytosol or basolateral membranes. Na-H antiporter activity, assessed as the amiloride-sensitive component of 22Na uptake, was measured in cultured proximal tubule cells exposed to 10% CO2 for 48 h. Na-H antiporter activity was significantly higher in cells exposed to 10% CO2 than in those exposed to 5% CO2. To evaluate the role of PKC, cultured cells were depleted of PKC by exposure to the active phorbol ester phorbol 12-myristate 13-acetate (PMA; 10(-7) or 10(-6) M) for 48 h before exposure to 10% CO2. In the presence of 10% CO2, Na-H antiporter activity was significantly lower in PKC-depleted cells than in control. In addition, sphingosine, an inhibitor of PKC, also prevented the adaptation of the Na-H antiporter to 10% CO2 as compared with 5% CO2. In cells treated with the inactive analog 4 alpha-PMA, 22Na uptake was not different than that in control. PMA-treated cells also had a decrease in Na-H antiporter activity during exposure to 5% CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Respiratory↗
PubMed1996

Potential effect of metabolic acidosis on beta 2-microglobulin generation: in vivo and in vitro studies.

Beta 2-microglobulin (beta 2M) is responsible for dialysis-associated amyloidosis. Level of beta 2M in plasma increase during chronic renal failure; however, retention does not appear to be the sole mechanism responsible. The effect of metabolic acidosis on beta 2M production was examined. Thirty-six patients with stable chronic renal insufficiency, 12 uremic patients before their first dialysis, 8 hemodialysis patients who were assigned to acetate or bicarbonate dialysate and then crossed over to the alternative regimen, and 6 normal subjects given NH4Cl to initiate metabolic acidosis were studied. In vitro studies in the human myeloid cell line U 937 were also performed. beta 2M protein was measured with ELISA, beta 2M mRNA was measured with reverse transcription polymerase chain reaction, and the U 937 cells were studied at two pH levels with FACScan flow cytometry. The cells were exposed in vitro up to 60 min in a buffered incubation medium to either pH 5.10 or pH 7.34. An inverse correlation was found between beta 2M and bicarbonate concentrations in plasma in the stable chronic renal failure patients (r = -0.54; P < 0.05) and in the uremic patients before their first dialysis (r = -0.72; P < 0.05). In hemodialysis patients, blood pH and plasma bicarbonate values were lower (P < 0.05) and beta 2M concentrations in plasma were higher (P < 0.05) with acetate than with bicarbonate dialysate. In normal men, NH4Cl resulted in an increase (P < 0.05) in beta 2M mRNA expression in lymphocytes by an average factor of 1.5 (range, 1.1 to 1.8). In U 937 cells, the cell surface expression of beta 2M and HLA Class I heavy chain assembled with beta 2M decreased at low pH compared with normal pH. Concomitantly, an increase in beta 2M release into the supernatant was observed, possibly as the result of beta 2M dissociation from cell surface HLA Class I complex. The results suggest that metabolic acidosis may enhance cellular beta 2M generation and release.

Acidosis↗
PubMed1997

Acidosis and coma after hemodialysis.

Ethylene glycol poisoning is a rare yet potentially fatal illness seen most commonly in association with ingestion by alcoholics or in suicide attempts. It is characterized by an elevated anion gap metabolic acidosis, osmolal gap, calcium oxalate crystals in the urine, and a well-defined clinical picture. Prompt treatment is crucial because effective intervention can prevent the neurologic, cardiac, pulmonary, and renal sequelae associated with ethylene glycol poisoning. Hemodialysis offers rapid clearance of ethylene glycol and its toxic metabolites. In this article, the case of a hemodialysis patient who suffered contamination of the dialysate solution with ethylene glycol, leading to altered mental status, coma, and severe anion gap metabolic acidosis, is reported. Despite prolonged dialysis and correction of the acidosis, the patient remained comatose and subsequently died.

Acidosis↗
PubMedDate not supplied

Lactobacillus GG does not affect D-lactic acidosis in diarrheic calves, in a clinical setting.

D-lactate, produced by gastrointestinal fermentation, is a major contributor to metabolic acidosis in diarrheic calves. Lactobacillus rhamnosus GG survives gastrointestinal transit in the neonatal calf and does not produce D-lactate. To determine whether this probiotic reduces gastrointestinal D-lactate production or severity of diarrhea or both, 48 calves (mean, 11 days old; range, 2-30 days) admitted to the clinic for treatment of diarrhea were randomly allocated to 2 groups. The experimental group was given Lactobacillus rhamnosus GG (1 x 10(11) cfu/d) PO, dissolved in milk or oral electrolyte solution, in addition to clinic treatment protocols; the other group served as a control. Serum and fecal samples were obtained at admission and at 24 and 48 hours after initial administration of Lactobacillus rhamnosus GG. All samples were analyzed for D- and L-lactate by using high-pressure liquid chromatography. Feces were also analyzed for pathogens, Lactobacillus rhamnosus GG recovery, and dry matter. D-lactic acidemia (>3 mmol/L) was present in 37/48 calves at admission. Lactobacillus rhamnosus GG was recovered in the feces of 13 experimental calves and 0 control calves 24 hours after administration. No difference in serum or fecal D- or L-lactate between the groups was detected at any time point. After therapy, D-lactic acidosis was absent at 48 hours in all but 1 calf. No relation between fecal pathogen (viral, bacterial, or protozoal) and degree of D-lactic acidosis was observed. The reduction in mortality and greater fecal dry matter in Lactobacillus rhamnosus GG-treated calves was not statistically significant.

Acidosis, Lactic↗
PubMed1999

Lactic acidosis in metformin therapy.

The biguanide drugs metformin and phenformin have been linked in the past to lactic acidosis, a metabolic condition associated with high rates of mortality. Although concern over the hyperlactataemic effect of phenformin led to the withdrawal of this drug from clinical practice in the 1970s, the situation with metformin has been less clear. Retrospective data indicate that, in metformin-treated patients with lactic acidosis, neither the degree of hyperlactataemia nor accumulation of metformin is of prognostic significance. Furthermore, the lowest rates of mortality were seen in patients with high plasma concentrations of metformin, which has led to the hypothesis that the drug may confer some benefit, linked to an increase in vasomotility, in such cases. Overall, it appears that mortality in patients receiving metformin who develop lactic acidosis is linked to underlying disease rather than to metformin accumulation, and that metformin can no longer be considered a toxic drug in this respect. These findings are likely to be of considerable relevance to the management of patients with type 2 (non-insulin-dependent) diabetes mellitus, especially where such patients are elderly.

Acidosis, Lactic↗
PubMed1992

Renal potassium wasting in distal renal tubular acidosis: role of aldosterone.

The pathogenesis of renal potassium wasting and hypokalemia in classic renal tubular acidosis (type 1 RTA) remains uncertain. The prevailing theory is that K(+)-Na+ exchange is stimulated due to an inability of the distal tubule to establish a normal steep lumen-peritubular H+ gradient. We encountered a 42-year-old woman with type 1 RTA associated with Sjögren's syndrome, in whom renal potassium wasting and hypokalemia persisted despite sustained correction of systemic acidosis with alkali therapy and increased intake of potassium. In addition, plasma renin activity was markedly increased and the serum aldosterone level was upper-normal despite the hypokalemia. Increased intake of sodium resulted in suppression on the serum aldosterone and correction of renal potassium wasting and hypokalemia. This case shows that secondary hyperaldosteronism, possibly due to an impairment of sodium conservation in the distal tubule, may contribute to the loss of potassium from the distal tubule even after the correction of acidosis.

Acidosis, Renal Tubular↗
PubMed1992

Hypokalemic paralysis associated with distal renal tubular acidosis.

A 68-year-old man had hydronephrosis due to ureteral stones for two months earlier and then increasing muscle weakness developed. A 30-year-old woman had rapidly progressive quadriparesis. In both cases, severe hypokalemia with metabolic acidosis was observed and the diagnosis of distal renal tubular acidosis was made. The former was considered to be an idiopathic incomplete form and the latter was a secondary complete form associated with Sjögren syndrome. Hypokalemic paralysis may occur as a complication of distal renal tubular acidosis.

Acidosis, Renal Tubular↗
PubMed1975

Insulin therapy in phenformin-associated lactic acidosis; a case report, biochemical considerations and review of the literature.

A patient with phenformin-associated lactic acidosis was treated with insulin and showed marked improvement coincident with the expected onset of action of the insulin administered. Relative insulin deficiency was demonstrated although several phenomena characteristic of phenformin-associated lactic acidosis obscured its reflection in the usual indices. From data presented and a review of the literature the following pathogenesis is proposed for the observed metabolic derangement. A background of relative insulin deficiency would permit enhanced pyruvate (and hence lactate) formation from protein sources. Insulin deficiency would also lead to inhibition of pyruvate dehydrogenase which slows pyruvate removal. Phenformin accumulation (cf impaired renal function) further reduces pyruvate removal by decreasing its conversion to glucose, but in addition alters the redox state. For the lactic acidosis which results, insulin administration may thus constitute specific therapy. Diabetes 24:28-35, January, 1975.

Acidosis↗
PubMed1975

Lactic acidosis associated with phenformin therapy. Evidence that inhibited lactate oxidation is the causative factor.

Using uniformly labeled 14C L-lactate, we have studied the turnover and oxidation of lactic acid in a patient who presented with a mild lactic acidosis while on phenformin medication. As with other cases of lactic acidosis associated with phenformin therapy, this subject had impaired renal function as evidenced by serum creatinine levels of 2 mg./100 ml. and BUNs of 40 mg./100 ml. Comparison of the rate of lactate oxidation relative to the rate of lactate turnover in this subject while on and off phenformin therapy suggests that a prime factor leading to the elevated lactate levels in this situation in impaired peripheral aerobic metabolism. Although lactate oxidation was increased in the presence of phenformin, the control studies clearly demonstrate that aerobic metabolism was not keeping pace with the increased level of anaerobic carbohydrate metabolism brought on by the drug. It is concluded that it is this imbalance in lactate metabolism that is responsible for the lactic acidosis that accompanies phenformin therapy.

Acidosis↗
PubMed1996

Phenformin-associated lactic acidosis due to imported phenformin.

OBJECTIVE: To emphasize the continued incidence of phenformin-associated lactic acidosis. CASE REPORT: We report a case of phenformin-associated lactic acidosis in a Chinese man who received phenformin while in China. Diagnosis was made; the patient was treated appropriately and survived. COMMENTS: Phenformin-associated lactic acidosis may still occur in the U.S.

Acidosis, Lactic↗
PubMed2004

Transient proximal renal tubular acidosis and Fanconi syndrome in a dog.

A 9-year-old spayed female Labrador Retriever was evaluated for anorexia, lethargy, and vomiting of 5 days' duration. Laboratory abnormalities included azotemia, high liver enzyme activities, hyperchloremic metabolic acidosis, glucosuria, ketonuria, proteinuria, and aminoaciduria. These laboratory abnormalities were diagnostic of proximal renal tubular acidosis and Fanconi syndrome. Results of initial and convalescent serologic tests for leptospirosis were negative. The dog was treated with amoxicillin, sodium bicarbonate, and potassium citrate at discharge. Repeated evaluations revealed resolution of the acidosis, azotemia, proteinuria, glucosuria, ketonuria, and high liver enzyme activities. Alkali administration was gradually discontinued, and the dog was clinically normal 8 months after discharge. The dog's clinical condition appeared to have been transient in nature, a phenomenon that is rarely seen in human or veterinary medicine.

Acidosis, Renal Tubular↗
PubMed1995

Feeding wet corn gluten feed to reduce subacute acidosis in cattle.

Two experiments were conducted to evaluate the effects of feeding wet corn gluten feed (WCGF) on subacute acidosis in cattle. In Exp. 1, 60 individually fed yearling steers (270 +/- 22 kg BW) were used in a 5 x 2 factorial arrangement of treatments. Steers were assigned to one of five dietary treatments: 1) dry-rolled corn (DRC), 2) 35% WCGF fed d 1 to 132, 3) 86.5% WCGF fed d 1 reduced to 35% WCGF by d 19 and increasing the proportion of DRC, 4) 86.5% WCGF fed d 1 to 132, or 5) 94.5% WCGF fed d 1 to 132. Final diets for Treatments 1 through 4 contained 92% concentrate and 8% alfalfa hay (DM basis). Treatment 5 was a 100% concentrate diet. All diets were fed with or without the addition of escape protein. During d 19 to 24, steers fed WCGF had less (P < .05) DMI variation than steers fed the control diet. Steers fed 86.5 and 94.5% WCGF had lower (P < .05) DMI and ADG than steers fed TReatments 1 through 3, although gain/feed was mot different (P > .10) In Exp. 2, three ruminally fistulated steers (615 +/- 36 kg BW) were used in a repeated 3 x 3 Latin square design. On d 14 of each period, 7.9 kg (DM) of 100% DRC, 50% DRC:50% WCGF, of 100% WCGF was intraruminally dosed as an acidosis challenge. Area within the curve below ruminal pH 6.0 was greater (P < .05) over a 24-h period for steers dosed with 100% DRC than for steers dosed with 50% DRC: 50% WCGF or 100% WCGF. In addition, more (P < .05) ruminal VFA accumulated over 24 h for steers dosed with 100% DRC. These data suggest that feeding WCGF does nor eliminate ruminal acidosis but may reduce the length of time cattle are exposed to the insult.

Acidosis↗
PubMed1997

Effect of steam-flaked sorghum grain density on performance, mill production rate, and subacute acidosis in feedlot steers.

Two trials were conducted to determine the effects of steam-flaked sorghum grain bulk density on animal performance, cost of production, and propensity to induce ruminal acidosis in feedlot steers. In Trial 1, 336 yearling steers (343 kg; SEM = .346) were fed diets for 125 d that contained sorghum grain (82.5%, DM basis) flaked to .283 (L), .322 (M), or .361 (H) kg/L (i.e., 22, 25, and 28 lb/bu). Steers fed L consumed 3.2% less DM than those fed H (linear, P < .05), resulting in 6.9% lower ADG (linear, P = .02) and 3.6% lower gain efficiency (linear, P < .15). Sorghum grain flaked to M and L had 16 and 46% greater starch gelatinization than H (measured using differential scanning calorimetry; linear, P = .002). Dressing percentage increased linearly (P < .05) with increasing flake density, but no other carcass measurements were affected by treatment. Increasing flake density increased mill production rate linearly (P < .01), resulting in the lowest energy usage per unit of flaked grain for the H treatment. Trial 2 was an acidosis challenge study that incorporated six ruminally cannulated steers (422 kg; SEM = .129) into a replicated 3 x 3 Latin square experiment. Reducing flake density resulted in linear reductions in ruminal pH following intake challenge at 3, 33, and 36 h after the d-12 challenge (P < .05). There was a linear increase in the area between the pH vs time curve and a line at pH 5.5 (P < .01) and 5.0 (P = .09) with decreasing flake density (28.0, 25.2, and 18.2 pH-hours below 5.5 and 9.6, 7.3, and 3.9 pH-hours below 5.0 for L, M, and H, respectively). Cattle consuming L also tended to have higher VFA concentrations (mM) at 36 h after challenge (P = .12). There was no significant treatment effect on ruminal lactate. Flaking sorghum grain to .283 and .322 kg/L resulted in reduced intake and poorer animal performance compared with .361 kg/L (58.7% starch gelatinization), higher susceptibility to subacute acidosis, and higher costs of production.

Acidosis↗
PubMed1998

Ruminal microbial and fermentative changes associated with experimentally induced subacute acidosis in steers.

We used six ruminally cannulated steers in a two-period crossover design to study ruminal fermentative and microbial changes associated with induced subacute acidosis. Steers were adapted to either an 80% alfalfa hay (hay-adapted)- or corn grain (grain-adapted)-based concentrate diet. After feed was withheld for 24 h, steers were overfed with an all-grain diet at 3.5 x NEm daily for 3 d. Ruminal contents and jugular blood samples were collected before withholding feed and at 0 and 12 h daily for 3 d during the overfeeding period. Ruminal samples were analyzed for pH, lactate, VFA concentrations, and counts of total anaerobic, amylolytic, lactic acid-producing and -fermenting bacteria, and ciliated protozoa. Blood samples were analyzed to assess acid-base status. Ruminal pH declined to a range of 5.5 to 5.0 with increased VFA concentrations, but normal lactate concentrations (<5 mM) were indicative of subacute acidosis. Total viable and amylolytic bacterial counts were higher (P < .05) in grain-adapted than hay-adapted steers. Anaerobic lactobacilli counts increased over time (P < .01) in both groups and were generally higher in grain-adapted than hay-adapted steers. Lactate-utilizing bacteria were initially greater in grain-adapted than hay-adapted steers and increased over time in both groups following grain challenge. Total ciliates were initially higher (P < .05) in grain-adapted than hay-adapted steers and decreased after 48 h in both groups. Blood acid-base changes were minimal. Bacterial changes associated with subacute acidosis resemble those reported during adaptation to grain feeding, and the decline in ciliated protozoa may be the only microbial indicator of a potentially acidotic condition in the rumen.

Acidosis↗
PubMed1998

Sheep fed grain prefer foods and solutions that attenuate acidosis.

We conducted experiments to determine whether lambs fed grain prefer foods and solutions containing sodium bicarbonate (NaHCO3) and lasalocid, compounds capable of attenuating acidosis. In Exp. 1, we determined whether lambs fed barley preferred flavored rabbit pellets (RP) containing NaHCO3 and lasalocid. Lambs in two groups (n = 10/group) were fed increasing amounts of barley on d 1 to 12 (300 to 1,100 g) and again on d 23 to 34 (300 to 1,350 g). After ingesting barley on d 1 to 12, lambs were fed ground RP containing lasalocid and NaHCO3 (i.e., medicated) and flavored with either 2% onion (group 1) or 2% oregano (group 2). During d 23 to 34, lambs were fed unmedicated RP containing NaCl and flavored with either 2% oregano (group 1) or 2% onion (group 2). During preference tests on d 35 to 40, lambs fed grain preferred RP with NaHCO3 to RP with NaCl (151 vs. 96 g; P < .01). In the Exp. 2, we determined whether wheat ingestion affected consumption of aqueous solutions containing NaHCO3. In trial 1, 28 lambs were assigned to four treatments: 1) low-wheat + 2% NaHCO3, 2) high-wheat + 2% NaHCO3, 3) low-wheat + water, and 4) high-wheat + water. For 12 d from 0800 to 0830, lambs in treatments 1 and 3 were fed 300 g of wheat and lambs in treatments 2 and 4 were fed up to 1,300 g of wheat; fluids (NaHCO3 and water) were then offered from 0930 to 1230 daily. Lambs drank more NaHCO3 on the high- than on the low-wheat diet (1,332 vs 890 g; P = .03); water consumption was similar for lambs on the high- and low-wheat diets (1,675 vs 1,700 g; P > .10). In trial 2, lambs in treatments 3 and 4 were offered a solution containing 1.4% NaCl. For 13 d from 0800 to 0830, lambs in treatments 1 and 3 were fed 500 g of wheat and lambs in treatments 2 and 4 were fed up to 1,700 g of wheat. Lambs had access to fluids from 0800 to 1200 daily. Lambs drank nearly twice as much NaHCO3 solution on the high- than on the low-wheat diet (1,066 vs 572 g), whereas they drank only 1.4 times more NaCl solution on the high- than on the low-wheat diet (888 vs. 634 g; P < .001). Fewer lambs showed signs of acidosis in treatment 2 than in treatment 4 in trials 1 (2 vs 9) and 2 (7 vs 17). Collectively, these results are consistent with the hypothesis that lambs fed grain prefer substances that attenuate acidosis.

Acidosis↗