ABSTRACT
We have determined the effects of orange juice on calcium bioavailability from CCM (a combination of CaCO3, citric acid, malic acid, 5:1:1, mol/mol/mol) and iron-calcium interaction by using whole body isotope retention techniques in rats. The mean calcium retention values from CCM were 42.8% from orange juice and 33.0% from water, a control. Orange juice significantly (p less than 0.05) improved calcium bioavailability. This enhancement of calcium absorption is independent of orange juice's pH and citric acid. Iron absorption from orange juice with CCM (36.7%) was also significantly higher than that from control (water) plus CCM (12.3%). Ascorbic acid at levels naturally present in orange juice failed to improve iron retention (12.3% vs 12.5%) from water plus CCM. In contrast, citric acid (at orange juice level) significantly (p less than 0.05) promoted iron absorption in the presence of CCM (8.0% vs 23.7%). The benefit of citric acid on iron-calcium interaction is enhanced by ascorbic acid. In the presence of both citric acid and ascorbic acid, at orange juice levels, iron absorption from water plus CCM (37.6%) was comparable to that from water without CCM (34.5%). These results show orange juice can deliver bioavailable calcium from CCM with minimal inhibition of iron absorption. Citric acid and ascorbic acid are likely the major orange juice components that contribute to the alleviation of iron absorption inhibition by CCM.
Subject(s)
Beverages , Calcium/metabolism , Citrus , Iron/metabolism , Absorption , Animals , Biological Availability , Hydrogen-Ion Concentration , Male , Rats , Rats, Inbred StrainsABSTRACT
A small translucent high-pressure chamber is introduced which has been exploited for local irradiation of tumour-bearing mice. The chamber has particularly proven to be valuable for high-pressure oxygen therapy together with simultaneous irradiation but can be used also for normal pressure and for gas other than oxygen. The chamber is shown during operation and a diagram illustrates design and technical data.
Subject(s)
Hyperbaric Oxygenation/instrumentation , Animals , Mice , Neoplasms, Experimental/radiotherapyABSTRACT
The mode of correction of the isodose curves from telecentric electron pendulous technique using a constant patient radius rp = 30 cm (Isodosenatlas, Siemens, 1973) is represented with regard to its application in patients with diverging surface contours. Correction is possible by two different methods: 1st by experimental determination of an air gap factor for the shift of isodoses, and 2nd by two factors depending on the focus-skin distance and on the angle of incidence of the electron beam. Determination of the factors is performed either by means of fixed fields measured by vertical and at oblique incidence of the beam and a depth dose distribution measured at the central axis, with oblique incidence of the electrons.
Subject(s)
Electrons , Radiotherapy, High-Energy/methods , Humans , Mathematics , Radiotherapy Dosage , SkinABSTRACT
The effects of 300 kV X-rays, 60Co gamma-rays, 43 MV X-rays and 43 MeV electrons on total cell RNA and 45 S pre-r RNA were investigated in Novikoff Hepatoma ascites cells. Six hours after local irradiation of the animals with 600 rad, the tumour cells were labelled in vivo for 30 and 60 min. The specific activities of high-molecular-weight RNA were influenced differently. This may be due to divergent effects of the applied radiation qualities at the level of transcription and transformation (processing). In addition, these radiation effects are mediated by the adrenal glands in a rather complex manner. Therefore, the results presented in this study support the suggestion that an in vivo labelling system is unsuitable for the evaluation of quantitative radiation effects on RNA.
