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[Computer experience and further developments in the respiratory function laboratory (author's transl)].

Reported is on satisfactory results obtained with a small-size computer consisting of punching and scanning device, as well as plain writing machine in the respiratory function laboratory. Developed in on- as well as off-line processing by an own technical staff, a diagnostic and teaching program was established for all respiratory function routine methods with the advantages of a large number of cases examined, elimination of sources of error, considerable supply of data and information, automatic documentation and filing, plain writing, interpretation and evaluation of findings. In continuation of such works also the blood gas analysis has been included. These values as the total of disturbances of the pathophysiological acid-base status are considered and interpreted. Clinical correction is forced in this man-machine dialogue by automatic stops of the whole machinery before going on. Subsequently and in addition are computer alveolar-arterial oxygen pressure gradient, venous shunt and oxygen saturation and expressed utilizing the capacity of the small-size computer. Further developments in the respiratory function diagnostic- and teaching program for small-size computers--not too expensive in the building block principle - are intended.

Acid-Base Equilibrium↗

[Effect of 1,4-benzodiazepine derivatives on the toxic action of oxygen under increased pressure].

The 1,4-benzodiazepine derivatives (diazepam, nitrazepm, lorazepam, clonazepam and two newly synthetized compounds of this series) increase the resistance of albino rats and rabbits to the toxic effect of oxygen under high pressure (7 and 5.5 atm respectively). The compounds under study are apt to avert over a long period the development of metabolic acidosis which appears following the action of high-pressure oxygen on the body.

Acid-Base Equilibrium↗

[Ionization of the acid-base groups of polyene antibiotics in aqueous solutions].

The acid-base characteristics of polyenic antibiotics, such as nystatin, mycoheptin and levorin in aqueous solutions were studied. A special procedure provided the use of potentiometric titration for investigation of ionization of the groups of vater-insoluble substances. The ionization constants of the carboxylic and amine groups of the antibiotics at several temperatures were determined. It was found that ionization of the acid group did not practically depend on the temperature. At the same time the heat effect of the amine group ionization was significant and amounted to about 10 kcal/mole. Thermodynamic analysis of the ionization process of the polyenic antibiotics in aqueous solutions was performed. Integral components defining the process energetics were calculated.

Acid-Base Equilibrium↗

Acid-base measurements of arterial, venous and capillary blood in the dog.

A method of arterial blood sampling acceptable for clinical purposes for acid-base estimations in dogs is described. A comparison of acid-base variables from fourteen canine arterial, venous and capillary blood samples revealed in most cases that venous and capillary blood samples showed unsatisfactory agreement with corresponding arterial blood samples. Two commercial automatic pH and blood-gas analysing systems are compared.

Acid-Base Equilibrium↗

Acid-base parameters in the dehydrated camel.

The effect of prolonged (10 days) dehydration on acid-base parameters of camel blood was examined. The pH and PCO2 levels rose significantly in the course of dehydration. This state was comparable with compensated non-respiratory alkalosis found in other animals. The plasma sodium, and magnesium levels rose significantly also. The plasma oxygen and calcium levels declined significantly. There were no significant changes in potassium and phosphate levels. It is concluded that the changes found in acid-base status following dehydration are further evidence of water preservation mechanisms in the dehydrated camel.

Acid-Base Equilibrium↗

[Changes in partial pressures of gases and of pH in the arterial blood of hypocapnic and hypercapnic subjects subjected to oxygen therapy].

The behaviour of partial tensions of respiratory gases and pH in the arterial blood was evaluated in anoxiaemic and hypercapnic (1st group) and hypo-eucapnic (IInd group) subjects undergoing oxygen therapy. The following phenomena were observed: 1) normalization in paO2 values in both groups; 2) statistically significant diminution in paCO2, especially as regards hypercapnic subjects; 3) statistically significant diminution in blood pH; 4) statistically significant diminution in bicarbonates. In the light of these findings, it is considered that other variables, such as the electrolytes, might play an important role in pH diminution during oxygen therapy and that further research should be carried out to look into the possibility.

Acid-Base Equilibrium↗

Acid-base balance and plasma composition in the aestivating lungfish (Protopterus).

Upon entering into aestivation, Protopterus aethiopicus develops a respiratory acidosis. A slow compensatory increase in plasma bicarbonate suffices only to partially restore arterial pH toward normal. The cessation of water intake from the start of aestivation results in hemoconcentration and marked oliguria. The concentrations of most plasma constituents continue to increase progressively, and the electrolyte ratios change. The increase in urea concentration is disproportionately high for the degree of dehydration and constitutes an increasing fraction of total plasma osmolality. Acid-base and electrolyte balance do not reach a new equilibrium within 1 yr in the cocoon.

Acclimatization↗

H in cortical peritubular capillaries of rat kidney.

The pH of peritubular capillaries was measured by means of antimony microelectrodes, during their perfusion with mammalian Ringer's solutions at different pH, in control and acetazolamide infused rats. In capillaries perfused with a solution more acid than blood, significant alkalinization was observed at increasing distances from the point of perfusion, while during perfusions with more alkaline solutions, acidification was observed. Plotting the pH change observed per micrometer of distance from the perfusion point against the pH of the perfusing solution, the pH in equilibrium with tubular cells was interpolated. A value of 7.51 +/- 0.01 was found for control rats, significantly higher than the mean arterial blood pH of this group, of 7.39. In acetazolamide infused rats an equilibrium pH of 7.44 +/- 0.02 was found, still higher than the blood pH of 7.34. The slope of these lines was significantly greater in control than in acetazolamide treated rats. This slope was shown to evaluate permeability to the ions responsible for acid-base balance. The present data suggest that peritubular alkalinization is reduced after carbonic anhydrase inhibition due to decreased peritubular permeability to the involved ions, which represents a further site of action of these inhibitors.

Acetazolamide↗

Lactate content and pH in muscle obtained after dynamic exercise.

Analyzes were made on muscle samples taken from the lateral part of the m. quadriceps femoris of man (lactate, pyruvate, and pH) on venous blood (lactate, pyruvate) and on capillary blood (pH). Samples were taken at rest, immediately after termination of dynamic exercise and during 20 min recovery from exhaustive dynamic exercise. Muscle pH decreases from 7.08 atrest to 6.60 at exhaustion. Decrease in muscle pH was linearly related to muscle content of lactate + pyruvate. The relationship was slightly different from what has been obtained after isometric exercise and this difference was ascribed to acid-base exchange with the blood during dynamic exercise. Lactate content was highly elevated in muscle after exercise and the concentration was 2-3 times higher than in blood. Pyruvate content was, however, only slightly higher than that at rest. During recovery, lactate content of muscle decreased exponentially with respect to time, whereas pyruvate content increased. The half-time of lactate decrease was 9.5 min. From the lactate dehydrogenase equilibrium relative values on NADH/NAD ratio could be calculated. It was found that NADH/NAD was highly increased after exercise and that it had not returned to the basal value after 20 min recovery.

Adult↗