I dag disputerte Svein Are Sirirud Vatnehol, ved Universitet i Oslo, institutt for klinisk medisin.
Disputasen ble gjennomført via videolink på grunn av de eksisterende korona-restriksjonene.
Hovedveileder har vært MR fysiker Trygve Holck Storås, University of Oslo
Professor Matthias J.P van Osch, Leiden University Medical Center
Professor Ingfrid Helene Salvesen Haldorsen, University of Bergen
Leder av evalueringskomiteen
Professor Bjørn Steen Skålhegg, University of Oslo
Ansvarlig for disputasen
Professor II Jonn Terje Geitung, University of Oslo
Oxygen enriched water is currently commercially available and often marketed with weakly or non-substantiated claims on health benefits. Unfortunately the research on such waters are inconclusive and there are, as of yet, no consensus on the possibility of the body to absorb the oxygen, much less if such uptake has a biological effect. The aim of this thesis was therefore to evaluate if Magnetic Resonance Relaxometry (MRr) could be used as a measurement tool to elucidate potential oxygen absorption.
Among the challenges in evaluating oxygen enriched water is where and how to measure a potential uptake or effect. Since the hepatic portal vein (HPV) is the communal vein for the gastro intestinal system this area appears to be a suitable target for analysis. Also since it is known that both dissolved oxygen (DO) and de-saturated hemoglobin (sO2) are weakly paramagnetic the concentration of these should be evident in MRr as a change in the T1 and T2*-relaxation times.
Since the effect of DO and sO2 on relaxation times, are relatively small optimized and quality controlled techniques are required. The first two thirds of this thesis therefore address the optimization of a technique for T1 measurements in the HPV. This technique, in combination with a T2*-measurement, was subsequently used in a randomized, double blinded, crossover trial to evaluate the changes of HPV relaxation times following ingestion of oxygenated and control water in a healthy population.
Regardless of water type, the ingestion of water resulted in relaxometry changes in accordance with water absorption. These changes were, however, increased when the participants drank oxygenated water. This increase cannot readily be attributed to increased DO or sO2 alone. A potential explanation for these findings is that increased levels of oxygen is utilized by the Na+/K+-ATPase pumps in the intestines to increase the rate of water transport across the epithelial tissue.