0000000000017140
AUTHOR
Jürgen Grote
Oxygen Diffusion Constants D and K of Tumor Tissue (DS-Carcinosarcoma) and Their Temperature Dependence
To understand more thoroughly the tumor O2 supply conditions, knowledge of O2 diffusivity in tumor tissue is required. Since exact measurements of the O2 diffusion constants of tumor tissue have not been carried out to date, previous investigations of tumor O2 supply had to employ estimated values (6 – 8, 10). The results of these studies are in part contradictory.
The Interdependence of Respiratory Gas Values and pH as a Function of Base Excess in Human Blood at 37°C
The accurate estimation of the transport function of human blood for respiratory gases as well as the respiratory gas exchange in human body requires detailed knowledge of the respiratory gas partial pressures and the acid-base status in the blood. Because there is an interdependence between the different respiratory gas parameters described as Bohr and Haldane effect (3,4), it is possible to obtain a general picture of the whole transport system, if these interrelations are known.
Die Bestimmung der Sauerstoffbindungskurve von hochverd�nnten H�moglobinl�sungen
Mit Hilfe einer von Thews (1960) fur Untersuchungen der O2-Diffusion in biologischen Medien angegebenen Versuchsanordnung werden Sauerstoffverbindungskurven von verdunnten Hamoglobinlosungen aufgenommen. Die Anwendbarkeit des Verfahrens fur die direkte und genaue Bestimmung von Sauerstoffbindungskurven wird theoretisch und praktisch uberpruft. Untersuchungen an hochverdunnten Losungen menschlichen Hamoglobins einer Konzentration von 16,4·10−3 g/100 ml und 16,4·10−4 g/100 ml fuhren zu folgenden Ergebnissen: Bei den Temperaturen 20, 30 und 37°C und dem pH-Wert 8,0 haben die Sauerstoffbindungskurven der untersuchten Hamoglobinlosungen typisch S-formige Verlaufsformen. Die Sauerstoffaffinitat d…
Respiratory Gas Transport in Blood during Pregnancy with Hemoglobin Concentrations Below 12g/100ml
During pregnancy the conditions for respiratory gas transport in blood and respiratory gas exchange differ from that of non-pregnant healthy women. The hemoglobin concentration and, consequently, the O2 capacity of blood decreases. The arterial CO2 tension falls between the 10th and the 40th week of gestation to values of about 30 mmHg, while the pH of the arterial blood during the same period was found to be nearly constant at an elevated level (7). Investigations of blood O2 affinity during pregnancy led to non-uniform results. Several investigators found no significant change whereas others described a significant decrease of blood O2 affinity in pregnant women and a mean P50 value of ab…
Respiratory Gas Transport in Heart
The purpose of this paper is to describe an attempt to obtain a better understanding of the dynamics of the oxygen supply of the myocardium under physiological and pathophysiological conditions by examining the oxygen diffusion in the heart muscle tissue during systole and diastole. In comparison to other organs the oxygen supply of the myocardium is characterized by a number of specific features. The most important one is that the gas exchange in the myocardium is a nonsteady-state diffusion process.
TISSUE OXYGENATION AND TISSUE METABOLISM IN THE BRAIN CORTEX DURING PRONOUNCED ARTERIAL HYPOCAPNIA
Publisher Summary This chapter describes the tissue oxygenation and tissue metabolism in the brain cortex during pronounced arterial hypocapnia. Acute arterial hypocapnia induced by hyperventilation leads to typical reactions in the circulation and the metabolism of the brain tissue. With a lowering of arterial CO2 tension, the cerebro-vascular resistance (CVR) increases resulting in a decrease of cerebral blood flow. The changes in CVR are a consequence of decreasing hydrogen ion and potassium ion concentrations in the perivascular space of the brain arterioles. The corresponding changes in the brain metabolism are characterized by elevated concentrations of lactate and pyruvate and an inc…
Die Messung der Leberdurchblutung mit der Kr-85 Clearance bei Ratten im Entblutungsschock
An Ratten mit normalem Blutdruck sowie bei stufenweiser Entblutung und stufenweiser Reinfusion wurde die Kr-85 Aktivitat der Leberoberflache nach intraportaler Injektion des in physiologischer Kochsalzlosung gelosten Isotops registriert. Aktivitatskurven in der Leberoberflache nach intraportaler Injektion von Kr-85 bei normalem und herabgesetztem Blutdruck von Ratten zeigen einen Abfall, der weitgehend einer Exponentialfunktion folgt. 50 Messungen der regionalen Leberdurchblutung von 15 Versuchstieren mit normalem Blutdruck ergaben bei der Auswertung nach Ingvar u. Lassen (1962) im Mittel eine Durchblutung von 1,4±0,54 ml/g · min und nach Zierler (1965) 0,95±0,32 ml/g · min. Die nach Zierle…
Cerebral Oxygen Supply in Brain Edema and During Ventriculo-Cisternal Perfusion
Numerous brain injuries and brain tumors lead to edema in brain tissue which can have consequences for the oxygen supply to the damaged tissue as well as to adjacent tissue areas. In studies made of the blood flow and oxygen supply in perifocal edematous tissue of brain tumors and lesions in patients undergoing various brain operations a direct relationship between the regional blood flow and the water content could be demonstrated (3). As the water content of the tissue increased, the blood flow through it diminished. In many cases, the reduction of the blood flow in the brain tissue induced an insufficient oxygen supply. In the tissue samples under investigation, the CrP and ATP concentra…
Effects of severe arterial hypocapnia on regional blood flow regulation, tissuePO2 and metabolism in the brain cortex of cats
The effect of a stepwise decrease in PaCO2 from 3.9-1.6 kPa on rCBF, rCMRO2, tissue PO2 and concentrations of glucose, lactate, pyruvate, ATP, ADP, AMP and phosphocreatine in the brain cortex was studied in cats lightly anaesthetized with sodium pentobarbital. 1. Moderate lowering of PaCO2 to 2.5 kPa induced in all animals a homogeneous decrease of rCBF in corresponding areas of the right and left hemisphere. Mean rCBF fell from 129.2 to 103.1 ml X 100 g-1 X min-1, while rCMRO2 remained unchanged (12.7-12.9 ml X 100 g-1 X min-1). The tissue PO2 frequency histograms showed a shift to lower values without indicating the presence of brain tissue hypoxia. 2. Severe arterial hypocapnia (PaCO2 = …
Oxygen diffusivity in tumor tissue (DS-Carcinosarcoma) under temperature conditions within the range of 20?40�C
The O2 diffusion constants D and K of tumor tissue (DS-Carcinosarcoma in the rat kidney) were determined at temperatures of 20, 30, 37, and 40 degrees C. The following mean values were obtained for the conditions of 37 degrees C: D = 1.75-10(-5) cm2/s and K = 1.9-10(-5) mlO2/cm-min-atm. Within the range of 20-40 degrees C, temperature variations in tumor tissue cause changes in the O2 diffusion coefficient D of 2.0-2.5%/C and in the Krogh O2 diffusion constant K of 0.5-1.5%/C. The measured O2 diffusion constants for tumor tissue correspond to values of normal tissue with similar water content. This indicates that the insufficient O2 supply in DS-Carcinosarcoma is due not to unfavorable O2 d…
Die Sauerstoffdiffusionskonstanten im Lungengewebe und Wasser und ihre Temperaturabhängigkeit
Es werden der O2-DiffusionskoeffizientD, die O2-LeitfahigkeitK (Kroghscher Diffusionskoeffizient) und der O2-Loslichkeitskoeffizient α im Lungengewebe und Wasser und ihre Temperaturabhangigkeit im Bereich zwischen 20 und 37° C bestimmt. Fur 37° C ergeben sich die oben aufgefuhrten Werte.
Corneal Oxygen Supply Conditions
Pronounced cornea hypoxia induces swelling and a loss of transparency. Hypoxia of longer duration causes necrosis, particularly of the corneal endothelium. These findings were observed after ligation of the cilial arteries and the arteria carotis interna, after reduction of oxygen tension on the anterior corneal surface as well as after prolonged wearing of ill-fitted contact lenses (11, 15, 18, 22, 23). Because the normal function of the corneal endothelium plays a central role in maintaining transparency, an insufficient endothelial oxygen supply can directly influence vision (3, 17).