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Bartels, H.; Bücherl, E. S.; Hertz, C. W.; Rodewald, G.; Schwab, Max

doi:10.1007/978-3-642-52983-2

Cited by 173 publications

(33 citation statements)

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“…Estimation of the olive oil: water partition coefficients of acetic, propionic and butyric acid. -VFA were added singly or in mixture to -1-molar phosphate-buffer solution (KH2PO4 and Na2HPO4 in proportions according to the required pH [Bartels et al, 1959]. This solution was mixed with olive oil (DAB 6) at 39TC.…”

Section: Methodsmentioning

confidence: 99%

Absorption of Volatile Fatty Acids, Tritiated Water and Antipyrine From the Abomasum of Goats

1968

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In conscious goats the abomasum was isolated temporarily from the rest of the gastro-intestinal tract by means of balloons, or a double by-pass or a snare around the pylorus. Abomasal contents, rumen fluid or a saline solution were given into the abomasum. Altogether forty experiments were done on four goats.The absorption of acetic acid, propionic acid, butyric acid, tritiated water (HTO) and antipyrine (AP) from the abomasum was measured. For comparison of the absorption rates, the data were given as clearance of the abomasal fluid and as water (liffusion.At a mean abomasal fluid volume of 606 ± 201 ml., 513 ± 169 ml. water diffused out of the abomasum through the abomasal mucosa per hour. The antipyrine clearance was 214 ± 84 ml./hr. The volatile fatty acids (VFA) were absorbed considerably faster at acid than at neutral pH values; at pH 5-2 -5-6 the VFA clearance was only 320 ml./hr.: at pH 3-5-4-0, however, it increased to 1130 ml./hr.The olive oil: water partition coefficients for acetic, propionic and butyric acid were measured in the pH range of 3-5 -6-2. With decreasing pH values the degree of dissociation of the acids decreases and the lipid solubility increases considerably.The permeability of the abomasal and ruminal mucosa for VFA also increases at lower pH values, but not as much as the olive oil: water partition coefficients of the acids.Absorption of VFA, HTO and AP from the abomasum is discussed in relation to the absorption of these substances from the rumen and the human stomach.

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Section: Methodsmentioning

confidence: 99%

Absorption of Volatile Fatty Acids, Tritiated Water and Antipyrine From the Abomasum of Goats

1968

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“…(15) are plotted against the measured 4P02. The ~~ value was 66.3 mmol/(l RBC • pH), the a f was taken to be 0.0325 mmol/(l fluid • Torr) (BARTELS et al, 1959), and Po, Ht, (HC03 j2(Y), and 4(HC03-)2*(YZ) were cited from the measured values. The regression line was given by 4Pco2(calc.…”

Section: P02 Increased With the 4(hc03-)f(yz) And The Ratio Of Dpco2/mentioning

confidence: 99%

“…where Ht is the fractional hematocrit after the mixing, a~, C02 solubility in the RBC, 0.026 mmol/(l RBC • Torr) ( VAN SLYKE et al, 1928 ;BARTELS et al, 1959). Carbamate content in the oxygenated RBC was estimated to be 1.0 mmol/l RBC according to TAZAWA et al (1983).…”

mentioning

confidence: 99%

Change in PCO2 in red cell suspension following bicarbonate shift.

Shimouchi¹,

Mochizuki²,

Niizeki³

1984

Jpn.J.Physiol

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To reveal the C02 diffusion process into and out of the red blood cell (RBC), changes in Pco2 following the HC03-shift were examined. The RBC suspension was mixed at 37°C with saline solution having different HC03-concentrations. In proportion to the intracellular HC03-change caused by the HC03-shift, the P02 change was increased. The rate of change increased as the hematocrit and the initial intracellular HC03-content decreased. For calculating the above Pco2 change, a theoretical equation was derived from the HendersonHasselbalch equation and the relation between both the changes in buffer base and intracellular pH. The calculated Pco2 change coincided well with the measured value, suggesting the validity of the theoretical equations.Key Words: HC03-shift, Pco2 change, Henderson-Hasselbalch equation, intracellular pH, buffer value.For clarifying C02 exchange rate in vivo, it is necessary to determine the diffusion rates of C02 and HC03-into and out of the red blood cell (RBC) as well as their interactions with oxygen. For estimating the above diffusion rates a simulation method using solutions of the diffusion equations for C02 and HC03-may be the most suitable at the present time. To solve the equations numerically, in turn, such parameters as the diffusion coefficients and the permeabilities of C02 and HC03-across the RBC membrane are indispensable. Recently, NIIZEKI et al. (1984) measured the rate of HC03-shift in the RBC in which carbonic anhydrase was not inhibited. They ascertained that the Pco2 in the RBC was increased due to HC03-influx, causing outward C02 diffusion, and the outflow of HC03-caused a decrease in intracellular Pco2 and subsequently the inward C02 diffusion. In general, the HC03-shift occurs whenever C02 molecules diffuse into or out of the RBC. Therefore, the phenomenon that the HC03-shift causes the secondary C02 diffusion is very important in obtaining the theoretical equations for the C02 and HC03-diffusions.

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“…Assuming that the C02 solubility in the boundary layer surrounding the RBC is equal to that of RBC interior, 0.583 x 10_ 3 ml/(ml. Torr) (BARTELS et al, 1959), the C02 permeability is estimated to be 4.29 x 10_3 cm/sec, being about 60 % of the Forster's value. Taking the approximation used in the computation into account, the ,(C02) of 2.5 x 10-6 cm/(sec .…”

Section: Hc03-profiles Ofmentioning

confidence: 82%

“…C02 solubilities in RBC and saline solution are the values reported by VAN SLYKE et al (1928) andBARTELS et al (1959). The diffusion coefficients for C02 and HC03-, D(C02), and D(HC03-) were cited from UCHIDA et al (1983).…”

Section: Derivation Of Numerical Solutionmentioning

confidence: 89%

Numerical solution of partial differential equations for CO2 diffusion accompanying HCO3- shift in red blood cells.

Kagawa¹,

Mochizuki²

1984

Jpn.J.Physiol

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A computer program for a numerical solution of the C02 diffusion in the red blood cell including the HC03-shift was developed. Comparing the calculated extracellular Pco 2 curve with the experimental data on the primary and secondary C02 diffusions, the permeabilities of C02 and HC03-across the red cell membrane, i2(C02) and i(HC03-), were determined as i2(C02)=2.5 x 10-6 cm/(sec . Torr), Inward i(HC03-) =5 x 10-4 cm/sec , Outward ~(HC03-)=7 x 10-4 cm/sec. The dependencies of the C02 diffusion rate on the hematocrit and initial intraand extracellular HC03-concentrations were examined using the above permeabilities. The half-time of the extracellular PC02 change in a closed RBC suspension was obviously reduced as the hematocrit and initial extracellular HC03-increased, while the effect of the initial intracellular HC03-was not significant. The C02 diffusion in vivo was simulated using pulmonary and tissue capillary models. The half-time of the extracellular HC03-change was about 0.15 sec, while that of the intracellular HC03-change ranged from 40 to 60 msec. Despite the considerable interest in the interaction of CO2 and 02 diffusions into and out of the red blood cells (RBC), the C02 diffusion process into the RBC has not been explained theoretically. Insofar as the two compartment model (HILL et al., 1973;FORSTER and CRANDALL, 1975) was used, the above interaction cannot be calculated. KERNOHAN et al. (1963) reported that the C02 hydration and dehydration reactions occur so fast in the RBC that the chemical equilibrium is established within 1 msec. Therefore, because the intracellular Pco2 change is mainly limited by the C02 and HC03-diffusions, we attempted to solve the differential equations for the diffusion numerically in a disc RBC model. In an effort to obtain a numerical solution, NIIZEKI et al. (1983) measured the diffusion rate of C02 in the RBC in a closed RBC suspension. In their experiment on the

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Cited by 173 publications

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Absorption of Volatile Fatty Acids, Tritiated Water and Antipyrine From the Abomasum of Goats

Absorption of Volatile Fatty Acids, Tritiated Water and Antipyrine From the Abomasum of Goats

Change in PCO2 in red cell suspension following bicarbonate shift.

Numerical solution of partial differential equations for CO2 diffusion accompanying HCO3- shift in red blood cells.

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