Ion transport and acid-base balance in freshwater bivalves

1997 ◽  
Vol 200 (3) ◽  
pp. 457-465
Author(s):  
R Byrne ◽  
T Dietz

Blood acid­base and ionic balance in freshwater bivalves is affected by the relative activities of epithelial Na+ and Cl- transporters. In the unionid Carunculina texasensis, the Na+/H+ exchanger is the predominant epithelial transporter that affects acid­base state, while Cl-/HCO3- exchange is of lesser importance. In the corbiculid Corbicula fluminea, Cl- and Na+ transport are both significant components affecting acid­base state. Serotonin (5-hydroxytryptamine, 5-HT) stimulates Na+ and Cl- transport in both species. In C. texasensis, the effect of exogenous serotonin is four times greater on Na+/H+ exchange than on Cl-/HCO3- transport, resulting in an increase in acid secretion and a rise in blood pH. In a Na+-free environment, serotonin had no effect on blood acid­base state in C. texasensis. In C. fluminea, the acid­base consequences of serotonin stimulation of Na+/H+ exchange were offset by similar increases in Cl-/HCO3- exchange and by alterations in blood PCO(sum) in medium containing Na+. In Na+-free medium, stimulation of the Cl- transporter with 5-HT resulted in a decrease in blood pH. The differences between these two species are related to the reliance of C. fluminea on Cl- as the major anion in the blood, requiring high levels of epithelial Cl- transport. In C. texasensis, the anionic component of the blood consists of both Cl- and HCO3- and these ions are interchangeable over a wide concentration range. Extracellular acid­base balance in freshwater bivalves is governed, in part, by epithelial ion transporters.

2007 ◽  
Vol 292 (3) ◽  
pp. G899-G904 ◽  
Author(s):  
Markus Sjöblom ◽  
Olof Nylander

When running in vivo experiments, it is imperative to keep arterial blood pressure and acid-base parameters within the normal physiological range. The aim of this investigation was to explore the consequences of anesthesia-induced acidosis on basal and PGE2-stimulated duodenal bicarbonate secretion. Mice (strain C57bl/6J) were kept anesthetized by a spontaneous inhalation of isoflurane. Mean arterial blood pressure (MAP), arterial acid-base balance, and duodenal mucosal bicarbonate secretion (DMBS) were studied. Two intra-arterial fluid support strategies were used: a standard Ringer solution and an isotonic Na2CO3 solution. Duodenal single perfusion was used, and DMBS was assessed by back titration of the effluent. PGE2 was used to stimulate DMBS. In Ringer solution-infused mice, isoflurane-induced acidosis became worse with time. The blood pH was 7.15–7.21 and the base excess was about −8 mM at the end of experiments. The continuous infusion of Na2CO3 solution completely compensated for the acidosis. The blood pH was 7.36–7.37 and base excess was about 1 mM at the end of the experiment. Basal and PGE2-stimulated DMBS were markedly greater in animals treated with Na2CO3 solution than in those treated with Ringer solution. MAP was slightly higher after Na2CO3 solution infusion than after Ringer solution infusion. We concluded that isoflurane-induced acidosis markedly depresses basal and PGE2-stimulated DMBS as well as the responsiveness to PGE2, effects prevented by a continuous infusion of Na2CO3. When performing in vivo experiments in isoflurane-anesthetized mice, it is recommended to supplement with a Na2CO3 infusion to maintain a normal acid-base balance.


2020 ◽  
Vol 44 (1) ◽  
Author(s):  
V. A. Kashirin ◽  
O. V. Khorolets ◽  
S. I. Andreev ◽  
A. A. Mikheev

Abstract The characteristic for most solid tumors cells is the intracellular alkalinization and acidification of the extracellular milieu and this pH gradient inversion (pHe < pHi) is associated with tumor proliferation, invasion, metastasis, aggressiveness, and treatment resistance. However is there tumor pH (pHi and/or pHe) changes affect on venous blood plasma pH? Purpose of the study. The venous blood acid-base balance before and after the combined treatment, correlation of the venous blood pH indicators (pHb), relationship neoplasm and blood pH in patients with laryngeal cancer was study. Material and methods. Studies were performed in patients with laryngeal cancer categories T2–3 N0 M0 before and after the combined treatment. The patients were divided into four groups: Group 1 – 25 patients before the start of treatment; Group 2 – 21 patients (from Group 1) after completion of the combined treatment; Group 3 – 14 patients from Group 2 with positive results of treatment and Group 4 – 7 patients from Group 2 with a negative result of treatment (recurrence and/or metastasis of the neoplasm). The control group consisted of 15 practically healthy people (Group C). Examination of venous blood acid-base balance of patients, tumor pH and tumor cells pHi and pHe was carried. Results and discussion. The increase in pCO2 and HCO – concentration will result in decrease in the pH, but if these indicators have a clear correlation in the control group, then in patients groups there was a correlation for pHb & pCO2 and pO2 only. Besides, we marked increase in pCO2, HCO –, K+, while pO decreased in pHb after the combined treatment. It is necessary to point out the differences between some benchmarks and indicators of acid-base balance in the plasma of venous blood in primary patients and patients with recurrent laryngeal cancer. So, if pHb, pO2, and Cl– patients have statistically significant differences from control data, then differences with control pCO2 values are characteristic only for patients of Groups 1 and 3. On the contrary, differences in the HCO – indices are characteristic only for patients of Group 4. There are statistically significant differences from the control indicators K+, Na+, Ca2+, Glu, Lac, mOsm in patients of the first group and Cl– and Lac of patients in the third group. Among the indicators in the third and fourth groups of patients, statistically significant differences were noted in the values of pHb, HCO – and Glu.In patients of groups 1 and 4, the determination of pHt and the calculation of pHi, pHe revealed decrease in pHt and pHe with increasing pHi in patients with recurrence of the neoplasm.The final stage of the study was to determine the relationship (and not correlation) of blood pH and laryngeal tumors and the relationship was noted in the «pHb-tumor» system in primary patients, but in patients in 3 and 4 Groups, that «pHb-tumor» connection is rather contradictory. Conclusion. Acid-base balance indicators obviously cannot be considered as unconditional markers of carcinogenesis, but their monitoring and, in particular, venous blood pH, of patients after special treatment, can help determine the risk group of patients who may develop of a malignant neoplasm recurrence. Keywords: acid-base balance, laryngeal cancer, se, prognosis.


2014 ◽  
Vol 83 (1) ◽  
pp. 29-36
Author(s):  
Jędrzej Przystanowicz ◽  
Barbara Zielińska-Psuja ◽  
Joanna Kowalówka-Zawieja ◽  
Karina Sommerfeld

Introduction. Ethylene glycol (EG) is relatively nontoxic but undergoes a multi-step oxidation to toxic metabolites, aldehydes and acids. The accumulation of organic acids, mainly glycolates, leads to the development of profound, life-threatening metabolic acidosis. A key therapy is an antidotal treatment with fomepizole (4-MP), the inhibitor of the first step of EG biotransformation enzyme, alcohol dehydrogenase.Aim. The aim of the study was to demonstrate the efficacy of fomepizole in the prevention of acid-base balance disorders in acute ethylene glycol poisonings in rats.Material and methods. Adult male Wistar rats were given EG (p.o.) with single (i.p.) or multiple (p.o.) doses of 4-MP (EG 3830 and 5745 mg/kg, respectively, 4-MP in single dose of 10 mg/kg or 15 mg/kg followed by 10 mg/kg every 12 hours). Blood gas analysis was performed and blood pH, bicarbonate concentration and base excess were evaluated.Results and conclusions. The single dose of 4-MP was effective in preventing a decrease in blood pH, bicarbonate concentration and base excess during the entire experimental period (pH 7.35 vs 7.21 at hour 12, bicarbonate concentration 27.2 vs 18.3 mmol/dm3 at hour 8, base excess 1.8 vs -8.2 mmol/dm3 at hour 18). The multiple administration of 4-MP started 2 hours after EG poisoning resulted in rapid restoration of proper values of acid- -base balance parameters. Fomepizole is highly efficacious in restraining the acid-base balance disorders which are concomitant with acute ethylene glycol poisonings.


1989 ◽  
Vol 67 (8) ◽  
pp. 2065-2073 ◽  
Author(s):  
George K. Iwama ◽  
James C. McGeer ◽  
Mark P. Pawluk

Some physiological aspects of five fish anaesthetics in rainbow trout were investigated. The effects of benzocaine, 2-phenoxyethanol, MS-222 (Sandoz), metomidate, and carbon dioxide gas (CO2) on acid–base regulation, hematocrit, blood gases, and cortisol and adrenaline concentrations were determined in resting rainbow trout fitted with chronic catheters in the dorsal aorta. A severe hypoxia developed with the cessation of breathing in deep anaesthesia. This was accompanied by a rise in blood [Formula: see text] and adrenaline concentration, and a fall in blood pH. Blood bicarbonate concentrations remained unchanged and cortisol concentrations declined with time. There was a transient increase in hematocrit coinciding with the increase in adrenaline concentrations.


1987 ◽  
Vol 65 (4) ◽  
pp. 489-498 ◽  
Author(s):  
J. T. Brosnan ◽  
M. Lowry ◽  
P. Vinay ◽  
A. Gougoux ◽  
M. L. Halperin

The purpose of this review is to examine the factors regulating ammonium production in the kidney and to place these factors in the perspective of acid–base balance. Renal ammonium production and excretion are required to maintain acid–base balance. However, only a portion of renal ammonium production is specifically stimulated by metabolic acidosis. One should examine urinary ammonium excretion at three levels: distribution of ammonium between blood and urine, augmented glutamine metabolism, and an energy constraint due to ATP balance considerations. With respect to the biochemical regulation of acid–base renal ammonium production, an acute stimulation of α-ketoglutarate dehydrogenase by a fall in pH seems to be important but this may not be the entire story. In chronic metabolic acidosis augmented glutamine entry into mitochondria (dog) or increased phosphate-dependent glutaminase activity (rat) become critical to support a high flux rate. Metabolic alterations, which diminish the rate of oxidation of alternate fuels, might also be important. The above principles are discussed in the ketoacidosis of fasting, the clinically important situation of high rates of renal ammonium production.


2015 ◽  
Vol 18 (1) ◽  
pp. 207-215 ◽  
Author(s):  
M. Bednarski ◽  
R. Kupczyński ◽  
P. Sobiech

AbstractThe aim of this study was to analyze disorders of acid-base balance in calves with chronic diarrhea caused by mixed, viral, bacterial andCryptosporydium parvuminfection. We compared results obtained with the classic model (Henderson-Hasselbalch) and strong ion approach (the Steward model). The study included 36 calves aged between 14 and 21 days. The calves were allocated to three groups: I – (control) non-diarrheic calves, group II – animals with compensated acid-base imbalance and group III calves with compensated acid-base disorders and hypoalbuminemia. Plasma concentrations of Na+, K+, Cl−, Cl2+, Mg2+, P, albumin and lactate were measured. In the classic model, acid-base balance was determined on the basis of blood pH, pCO2, HCO3−, BE and anion gap. In the strong ion model, strong ion difference (SID), effective strong anion difference, total plasma concentration of nonvolatile buffers (ATot) and strong ion gap (SIG) were measured.The control calves and the animals from groups II and III did not differ significantly in terms of their blood pH. The plasma concentration of HCO3−, BE and partial pressure of CO2 in animals from the two groups with chronic diarrhea were significantly higher than those found in the controls. The highest BE (6.03 mmol/l) was documented in calves from group II. The animals from this group presented compensation resulted from activation of metabolic mechanisms. The calves with hypoalbuminemia (group III) showed lower plasma concentrations of albumin (15.37 g/L), Cl−(74.94 mmol/L), Mg2+(0.53 mmol/L), P (1.41 mmol/L) and higher value of anion gap (39.03 mmol/L). This group III presented significantly higher SID3(71.89 mmol/L), SID7(72.92 mmol/L) and SIG (43.53 mmol/L) values than animals from the remaining groups (P<0.01), whereas ATot(6.82 mmol/L) were significantly lower. The main finding of the correlation study was the excellent relationship between the AGcorrand SID3, SID7, SIG. In conclusion, chronic diarrhea leads to numerous water-electrolyte disorders. Characterization of acid-base disturbance in these cases suggests that classic model have some limitations. This model can not be recommended for use whenever serum albumin or phosphate concentrations are markedly abnormal.


1995 ◽  
Vol 75 (1) ◽  
pp. 145-151 ◽  
Author(s):  
C. Fauchon ◽  
J. R. Seoane ◽  
J. F. Bernier

Twenty-four castrated lambs (32.4 ± 4.1 kg BW) were used to study the effect of varying dietary cation–anion concentration [C–A] on performance and acid–base balance. The diets contained approximately 100, 300, 500 and 700 mequiv Na + K − Cl kg−1 of feed. Each group of six lambs was fed one of the diets ad libitum during a 6-wk test. Increasing the [C–A] of the diets resulted in higher feed intake and higher daily gains (P < 0.01) without affecting feed efficiency. Apparent digestibility of nutrients was not affected by the dietary treatments but a negative relationship was found between intake and energy digestibility (P < 0.01). Blood pH was lower in lambs receiving the 100 [C–A] diet (P < 0.05). Blood bicarbonate and base excess increased as [C–A] in the diet increased from 300 to 700 mequiv (P < 0.05). Plasma Mg concentration decreased with increasing dietary [C–A] (P < 0.01). Urinary pH and urine volume increased as [C–A] in the diet increased (P < 0.01). The results indicate that diets containing between 500 and 700 mequiv Na + K − Cl kg−1 stimulated growth by allowing greater feed intake and greater daily gains with little effect on nutrient digestibility. Blood profile showed a systemic response to dietary changes in [C–A], but indicated that lambs were able to adapt to cation loads since the values obtained for acid–base balance were within physiological range for lambs. Key words: Cation–anion, acid–base, lambs


2021 ◽  
Vol 12 (1) ◽  
pp. 20-39
Author(s):  
Hassan Bahrami ◽  
Ted Greiner

The changing diets accompanying our modern life style have increased the content of foods that form acidic metabolic waste residues in the body. Wastes from these metabolic processes are released into the interstitial fluids and the blood, slightly changing their pH temporarily. This link may in turn have an impact on the incidence of non-communicable diseases (NCDs). According to Warburg effect theory, an acidic cellular and circulatory environment may cause various specific health problems such as hypoxia and cancer, whereas an oxygen-rich optimum-alkaline environment could retain healthy cells. However, the mechanisms by which the diet may be influential on blood pH-related parameters and on health have remained largely unknown. This paper begins with a detailed presentation of the concepts, issues and the existing evidence regarding alkaline and acid forming diets, and summarizes the three main mechanisms by which the diet influences the acid-base balance in the body. It then presents the findings of a small exploratory study in which one author (HB) followed diets traditionally thought to produce alkaline or acidic residues. After each diet period of one month (with a two-month wash out period), pH, oxygen saturation, and carbon dioxide partial pressure were measured for arterial and for venous blood.   The resulting data indicated that the diets followed changed blood pH-related parameters in the expected directions according to the acid-base theory of health. Increased intake of acid-forming foods resulted in a slightly lower pH level, but a significant reduction of oxygen saturation in the blood, whereas increased consumption of alkaline forming foods maintained the high oxygen saturation in the blood that, according to Warburg effect theory, may, if maintained, reduce the incidence of NCDs. Further cross-over research of this kind is needed, utilizing large samples and testing various dietary modifications.


Author(s):  
Michael M. Tymko ◽  
Christopher K. Willie ◽  
Connor A. Howe ◽  
Ryan L. Hoiland ◽  
Rachel Stone ◽  
...  

High-altitude exposure results in a hyperventilatory-induced respiratory alkalosis followed by renal compensation (bicarbonaturia) to return arterial blood pH(a) toward sea-level values. However, acid-base balance has not been comprehensively examined in both lowlanders and indigenous populations - where the latter are thought to be fully adapted to high-altitude. The purpose of this investigation was to compare acid-base balance between acclimatizing lowlanders, and Andean and Sherpa highlanders at various altitudes (~3,800, ~4,300, and ~5,000 m). We compiled data collected across five independent high-altitude expeditions and report the following novel findings: 1) at 3,800 m, Andeans (n=7) had elevated pHa compared to Sherpas (n=12; P<0.01), but not to lowlanders (n=16; nine days acclimatized; P=0.09); 2) at 4,300 m, lowlanders (n=16; 21 days acclimatized) had elevated pHa compared to Andeans (n=32) and Sherpas (n=11; both P<0.01), and Andeans had elevated pHa compared to Sherpas (P=0.01); and 3) at 5,000 m, lowlanders (n=16; 14 days acclimatized) had higher pHa compared to both Andeans (n=66) and Sherpas (n=18; P<0.01, and P=0.03, respectively), and Andean and Sherpa highlanders had similar blood pHa (P=0.65). These novel data characterize acid-base balance acclimatization and adaptation to various altitudes in lowlanders and indigenous highlanders.


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