scholarly journals The importance of metabolism in acid–base regulation and acid–base methodology

1989 ◽  
Vol 67 (12) ◽  
pp. 3005-3017 ◽  
Author(s):  
Hans-Otto Pörtner
Keyword(s):  
Integrated Control ◽  
Feedback Regulation ◽  
Urea Synthesis ◽  
Acid Base ◽  
Base Parameters ◽  
Recent Developments ◽  
Acid Base Status ◽  
The Relationship ◽  
Aerobic And Anaerobic

Metabolism not only affects the acid–base status of an animal by means of proton stoichiometries but, by feedback regulation, acid–base parameters (pH, [Formula: see text], bicarbonate) influence metabolic rates and the pathways used. This leads to a significant contribution of metabolism to acid–base regulation under both aerobic and anaerobic conditions. The relationship between amino acid metabolism, urea synthesis, and [Formula: see text] excretion is discussed as an example important for steady-state metabolic acid–base regulation during aerobiosis. Generally, acid–base relevant metabolism may be regulated through the effect of acid–base disturbances on hormonal mediation, allosteric modulation of enzyme proteins, pH optima, and the levels of substrates or products, some of these being acid–base relevant substances like bicarbonate, CO2, inorganic phosphate, and NH3. During functional or environmental anaerobiosis the same relationships prevail. Metabolic proton accumulation is counterbalanced by phosphagen depletion and ammonia accumulation in adenylate catabolism. In addition, in integrated control of metabolic and acid–base status, long-term (mitochondrial) anaerobiosis leads to reductions in metabolic rate and increased removal of acidic groups. The importance of metabolic processes in acid–base methodology is discussed in terms of traditional concepts and recent developments.

Mechanisms of Acid-Base Adjustment in Dogfish (Scyliorhinus Stellaris) Subjected to Long-Term Temperature Acclimation

1980 ◽  
Vol 85 (1) ◽  
pp. 89-98
Author(s):  
N. HEISLER ◽  
P. NEUMANN ◽  
G. F. HOLETON
Keyword(s):  
Temperature Acclimation ◽  
Temperature Adaptation ◽  
Acclimation Temperature ◽  
Acid Base ◽  
Temperature Changes ◽  
Base Parameters ◽  
Intracellular Compartments ◽  
Relationship Of ◽  
The Relationship

Specimens of Larger Spotted Dogfish (Scyliorhinus stellaris) were acclimated to a range of temperatures for 22–28 days. The relationships of pH to acclimation temperature in the extracellular space and in three intracellular compartments were essentially the same as previously observed in 24 h acclimated dogfish (Heisler, Weitz & Weitz, 1976). In dogfish subjected to elevated inspired PCO2 during acclimation to low temperature, there was an inversion in the relationship of acclimation temperature to plasma PCO2, and in that to plasma bicarbonate, whereas the relationships to pH values were unchanged. It is concluded that the temperature adaptation of the acid-base parameters is complete after 24 h of temperature acclimation. At least the following mechanisms are involved in the adjustment of pH with changes of temperature: changes of PCO2, changes of buffer pK values, and transmembrane transfer of bicarbonate. Apparently only one of them, the transmembrane transfer of bicarbonate, can be modulated in a sufficient range and is responsible for the final pH adjustment.

The Effect of Long-Term Aerial Exposure on Heart Rate, Ventilation, Respiratory Gas Exchange and Acid-Base Status in the Crayfish Austropotamobius Pallipes

1981 ◽  
Vol 92 (1) ◽  
pp. 109-124
Author(s):  
E. W. TAYLOR ◽  
MICHÈLE G. WHEATLY
Keyword(s):  
Heart Rate ◽  
Lactic Acid ◽  
O2 Consumption ◽  
Aerial Exposure ◽  
Acid Base ◽  
Bicarbonate Buffer ◽  
Content Difference ◽  
Acid Base Status ◽  
Lactate Levels

1. When first removed into air, crayfish showed transient increases in heart rate (fH) and scaphognathite rate (fR) which rapidly recovered to submerged levels and were unchanged for 24 h. The rate of O2 consumption(Moo2) increased from an initially low level and was then maintained for 24 h in air at the same level as in settled submerged animals. 2. There was an initial acidosis in the haemolymph which was both respiratory and metabolic due to the accumulation of CO2 and lactate. Progressive compensation by elevation of the levels of bicarbonate buffer in the haemolymph and reduction of circulating lactate levels returned pH towards submerged levels after 24 h in air. 3. Exposure to air resulted in a marked internal hypoxia with haemolymph O2, tensions, both postbranchial Pa, oo2 and prebranchial Pv, oo2, remaining low throughout the period of exposure. The oxygen content or the haemolymph was initially reduced, with a - vOO2 content difference close to zero. Within 24 h both Ca, oo2 and Cv, OO2 had returned towards their levels in submerged animals. These changes are explained by the Bohr shift on the haemocyanin consequent upon the measured pH changes. 4. After 48 h in air, MO2 and fH were significantly reduced and ventilation became intermittent. There was a slight secondary acidosis, increase in lactic acid levels and reduction in a - vO2 content difference in the haemolymph. 5. When crayfish were returned to water after 24 h in air, MOO2, fHfR were initially elevated by disturbance and there was a period of hyperventilation. In the haemolymph there was an initial slight alkalosis, and an increase in Ca, OO2 lactic acid. All variables returned to their settled submerged levels within 8 h.

The relationship between twin-to-twin delivery interval and umbilical artery acid-base status in the twin newborns

2005 ◽  
Vol 193 (6) ◽  
pp. S118
Author(s):  
Kyo Hoon Park ◽  
Joon-Seok Hong ◽  
Bo Hyun Yoon ◽  
Jong Kwan Jun ◽  
Joong Shin Park ◽  
...  
Keyword(s):  
Umbilical Artery ◽  
Acid Base ◽  
Acid Base Status ◽  
Twin Delivery ◽  
The Relationship

Long-term Effects of Dietary Anion-Cation Balance on Acid-Base Status and Bone Morphology in Reproducing Ewes

2003 ◽  
Vol 50 (10) ◽  
pp. 488-495 ◽  
Author(s):  
L. Espino ◽  
F. Guerrero ◽  
M. L. Suarez ◽  
G. Santamarina ◽  
A. Goicoa ◽  
...  
Keyword(s):  
Long Term Effects ◽  
Bone Morphology ◽  
Acid Base ◽  
Acid Base Status

scholarly journals Effects of sevoflurane and clonidine on acid base status and long-term emotional and cognitive outcomes in spontaneously breathing rat pups

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0173969 ◽  
Author(s):  
Nicole Almenrader ◽  
Paola Colucci ◽  
Valentina De Castro ◽  
Daniela Valeri ◽  
Maura Palmery ◽  
...  
Keyword(s):  
Cognitive Outcomes ◽  
Acid Base ◽  
Rat Pups ◽  
Acid Base Status ◽  
Spontaneously Breathing

Acid—Base Status in Dogs during Long Term Anaesthesia

1975 ◽  
Vol 80 (2) ◽  
pp. 77-82 ◽  
Author(s):  
B. Danielson ◽  
G. Grängsjö ◽  
B. Karlmark ◽  
H. R. Ulfendahl ◽  
M. Wolgast
Keyword(s):  
Acid Base ◽  
Acid Base Status

scholarly journals Acid-base status and cardiovascular function in mink (Mustela vison) anaesthetized with ketamine/midazolam

1996 ◽  
Vol 30 (1) ◽  
pp. 55-66 ◽  
Author(s):  
S. Wamberg ◽  
P. Svendsen ◽  
B. Johansen
Keyword(s):  
Heart Rate ◽  
Sodium Bicarbonate ◽  
Isotonic Saline ◽  
Cardiovascular Function ◽  
Spontaneous Respiration ◽  
Acid Base ◽  
Arterial Blood ◽  
Intravenous Solution ◽  
Acid Base Status

Heart rate, arterial blood pressure and blood acid-base status were determined in 18 adult female mink (mean (±SEM)body weight 1052±34 g)during long-term anaesthesia with either controlled ventilation ( n=12) or spontaneous respiration ( n=6) Surgical anaesthesia was induced by intramuscular injection of ketamine hydrochloride (Ketaminol Vet®, 40.0±1.7mg/kg) and midazolam hydrochloride (Dormicum® 2.8±0.1 mg/kg) and maintained for at least 5 h by continuous intravenous infusion of this drug combination in 0.9% saline. For all animals, the mean rates of infusion of ketamine and midazolam were 48.4±1.6 and 1.61±0.12 mg/h, respectively. Following continuous infusion of the anaesthetics in isotonic saline, at a rate of 20 ml/h, a moderate 'dilution acidosis' developed, which could be corrected by replacement of part of the saline with sodium bicarbonate to a final concentration of approximately 25 mmol NaHCO3 per litre. However, when the animals were allowed to breathe spontaneously, an increase in heart rate and a combined respiratory and metabolic acidosis occurred, due to severe respiratory depression. Apart from these effects and a few cases of increased salivation, no adverse effects over time were observed on the arterial blood acid-base status and cardiovascular function of the animals during ketamine/midazolam anaesthesia. It is concluded that the procedure described for long-term anaesthesia in mink is convenient and safe for acute physiological experiments in this species, provided normal body temperature and pulmonary gas exchange is sufficiently maintained. Thus, the need for an adequately controlled artificial ventilation is strongly emphasized. Finally, a proposal for the composition of an intravenous solution, containing ketamine and midazolam hydrochloride, and sodium bicarbonate in saline, suitable for long-term anaesthesia in adult mink is presented.

Is urea formation regulated primarily by acid-base balance in vivo?

1986 ◽  
Vol 250 (4) ◽  
pp. F605-F612 ◽  
Author(s):  
M. L. Halperin ◽  
C. B. Chen ◽  
S. Cheema-Dhadli ◽  
M. L. West ◽  
R. L. Jungas
Keyword(s):  
Dietary Protein ◽  
Urea Synthesis ◽  
Acid Base Balance ◽  
Severe Metabolic Acidosis ◽  
Acid Base ◽  
Wide Range ◽  
Base Balance ◽  
Acid Load ◽  
Acid Base Status

Large quantities of ammonium and bicarbonate are produced each day from the metabolism of dietary protein. It has recently been proposed that urea synthesis is regulated by the need to remove this large load of bicarbonate. The purpose of these experiments was to test whether the primary function of ureagenesis in vivo is to remove ammonium or bicarbonate. The first series of rats were given a constant acid load as hydrochloric acid or ammonium chloride; individual rats received a constant nitrogen load at a time when their plasma acid-base status ranged from normal (pH 7.4, 28 mM HCO3) to severe metabolic acidosis (pH 6.9, 6 mM HCO3). Urea plus ammonium excretions and the blood urea, glutamine, and ammonium concentrations were monitored with time. Within the constraints of non-steady-state conditions, the rate of urea synthesis was constant and the plasma glutamine and ammonium concentrations also remained constant; thus it appears that the rate of urea synthesis was not primarily regulated by the acid-base status of the animal in vivo over a wide range of plasma ammonium concentrations. In quantitative terms, the vast bulk of the ammonium load was converted to urea over 80 min; only a small quantity of ammonium appeared as circulating glutamine or urinary ammonium. Urea synthesis was proportional to the nitrogen load. A second series of rats received sodium bicarbonate; urea synthesis was not augmented by a bicarbonate load. We conclude from these studies that the need to dispose of excess bicarbonate does not primarily determine the rate of ureagenesis in vivo. The data support the classical view that ureagenesis is controlled by the quantity of ammonium to be removed.

Discordant Twins: Acid-Base Status

1991 ◽  
Vol 40 (3-4) ◽  
pp. 373-381 ◽  
Author(s):  
S.A. Ordorica ◽  
F.J. Frieden ◽  
I.A. Hoskins ◽  
B.K. Young
Keyword(s):  
Birth Weight ◽  
Acid Base ◽  
Apgar Scores ◽  
Twin Birth ◽  
Umbilical Blood ◽  
Base Parameters ◽  
Acid Base Status ◽  
Discordant Twins ◽  
A Prospective Study ◽  
Paired T Test

AbstractA prospective study was undertaken to determine the effect of twin birth-weight discordancy on Apgar scores and umbilical blood acid-base parameters. Using the paired t-test, small but statistically significant differences were seen in these parameters favoring the heavier twin over its lighter sibling. These differences were also affected by birth order, with the first-born being favored.

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