Biomedical subjects
Publications and source records attributed to K Hoornstra.
The toxic effects of Hytrast were studied on the peritoneum of laboratory rats in order to define the lethal dose and possible causes of toxicity. The results show that Hytrast, due to its toxicity, should not be used in any clinical situation where gastrointestinal tract perforation or leakage is a possibility.
The tissue reaction of seven contrast agents--pure barium sulphate, Micropaque, Hytrast, Dionosil, Gastrografin, Amipaque and Hexabrix-was evaluated on the mediastinum of rats. This work was undertaken to define the most suitable and safe contrast agent for use in the upper gastrointestinal tract in cases where leakage outside the gut into the mediastinum, pleura or peritoneal cavity may be suspected and aspiration may be an accompanying risk. Keeping in mind the danger of aspiration, Hexabrix and Amipaque appear to be the safest contrast media for the mediastinum.
This is an outline of a radiologic assessment of bone mineral measurements for diagnosis that is simple and low in cost. Bone mineral content equivalent values (BMCE) were determined of phalanges. Since phalanges have different dimensions the BMCE values per square millimeter surface area, bone mean mineral equivalent values (BMME) were determined. In normal subjects it was shown that over a period of 9 months a coefficient of variation for BMCE and BMME was found of 8 and 9%, respectively, indicating a change during the investigation period (precision of the technique has a CV for BMCE of 4% and for BMME of 3%). The clinical application of microdensitometry and of the single photon absorption method was tested and compared. Both methods resulted in similar findings, microdensitometry however also provides a qualitative assessment of bone characteristics.
The reactions of seven contrast agents--pure barium sulphate, Micropaque, Gastrografin, Dionosil, Hytrast, Amipaque and Hexabrix--on the bronchi and lungs of rats were studied. This work was undertaken to find a safe gastrointestinal contrast agent for use in post-operative patients where aspiration may be an accompanying risk. Amipaque and Hexabrix produced no significant histological reaction in the lungs and would, therefore, appear to be suitable for use in such cases.
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A method employing a special computer for determining the internal diameters of blood vessels from photofluorographic image is described; in vitro and in vivo experiments are performed with the system. The amount of contrast medium injected is restricted to 4 times 3 ml, and it is possible to determine the diameter (in the range from 2 to 16 mm) at any place where blood vessels can be catheterized. In the in vivo experiments the maximum systematic error is +/-5 percent in the 7 to 8 mm range.