O. Munck

The Fat Content of Leg Muscles and its Influence on the 133Xenon Clearance Method of Blood-Flow Measurement

The inert gas xenon, which is widely employed for organ blood-flow measurement, is highly soluble in lipids. The removal rate of xenon from an organ is therefore largely influenced by the fat content of the tissue.

Decomposition of iodine-labelled antipyrine.

The radiochemical stability of 4-iodoantipyrine-123 and 4-iodo-antipyrine-123I was examined under different circumstances by paper chromatography. The essential conclusions were (1) Use preferably the 123I-labelled compound. (2) Dilute the compound with water and not with saline. (3) Analyse each batch for radiochemical purity. (4) Although temperature is not a major factor in the decomposition of 4-iodoantipyrine storage at the lowest convenient temperature is advisable. (5) Purify the 131I-labelled compound before use.

[131I]Hippuran renography in normal subjects and in patients with essential hypertension.

Seventeen normal subjects and 21 patients with essential hypertension were examined by [131I]hippuran renography. Both groups were studied twice on the same day, first in a state of moderate dehydration and then after rehydration. From these data, four sets of reference intervals were established for several renographic parameters. Differences between the two groups were defined. The most impressive observation was a greater functional disparity between the two kidneys of one individual in the group of hypertensive patients, particularly when in a state of moderate volume depletion. This was reflected in a greater variance of certain kidney-to-kidney ratios derived from the renographic tracings. This article presents basic data to be utilized in clinical renography, as described in an accompanying article.

Fractional Intestinal Absorption and Retention of Calcium Measured by Whole-Body Counting. Application of a Power Function Model

By application of a power function model, fractional intestinal calcium absorption was investigated with a new technique involving whole-body counting after successive oral and intravenous administration of standard doses of 47Ca. The fractional calcium retention 7 days after the oral load of 47Ca was also measured. Fractional calcium retention averaged 30.3% in normal subjects and 11.5% in 11 patients with intestinal malabsorption. In the same groups fractional calcium absorption averaged 46.6% and 16.4%, respectively. Fractional calcium retention and intestinal calcium absorption were significantly correlated to body surface area, and there was a well-defined relation between fractional retention and absorption of calcium...

Diagnostic Value of Renography for Detection of Unilateral Renal or Renovascular Disease in Hypertensive Patients

In an effort to find an optimal set of renographic reference parameters for the study of hypertensive patients, the renographic data from 50 hypertensive patients with unilateral renal or renovascular disease were assessed against 95% confidence intervals obtained in normal subjects and in patients with essential hypertension in two different states of hydration. The highest all-over nosographic sensitivity and specificity were obtained by using the data from hydrated normal subjects as reference parameters. The nosographic sensitivity and specificity found in the selected series of hypertensive patients were converted to the clinically relevant predictive values of a positive and a negative test by assuming the prevalence of unilateral renal or renovascular disease in hospital populations of hypertensive patients to be 5% or 10%. In these model populations the predictive value of a postive was 33% and 51%, respectively. The predictive value of a negative test was higher than 99% for both populations. We find that predictive values of that order of magnitude are satisfactory for a test to be used in the initial phase of a diagnostic process.

Calcium metabolism in patients with chronic non-dialytic renal disease

Calcium metabolism was evaluated in 81 patients with chronic non-dialytic renal disease. Bone mineral content measured by photon absorptiometry was significantly lower than in normals, and serum alkaline phosphatase levels higher than in normals. However, the differences were small indicating that the calcium-metabolic disturbance was moderate. None of the patients suffered from overt osteomalacia.The mean serum level of 25-hydroxy-cholecalciferol (25-OH-D3) was slightly, but significantly higher than in normals studied at the same time of the year, but some patients and subnormal 25-OH-D3 levels. One such patient was given a daily dose of 1200 U of vitamin D3 by mouth for 3 weeks. Hereafter, the serum 25-OH-D3 concentration rose progressively to high normal values. These two observations would suggest that the hepatic 25-hydroxylation in such patients is unimpaired.The results are in accordance with the existence of a subclinical vitamin D deficiency in patients with non-dialytic renal disease, due to an impaired production of 1,25-(OH)2D3. It is an open question whether such patients should be given (prophylactic) treatment with 1α-hydroxycholecalciferol.

The function of a continuous medication system in subatmospheric pressure environment

The pumping rate of Alzet mini-osmotic pumps was examined in different environments by use of 125J-hippuran. There was a marked increase in pumping rate under hypobaric conditions (PB = 360 mmHg = 48kPa).

Treatment of Osteoporosis with Calcium Infusions an Osteodensitometric Study

It has recently been suggested that osteoporosis results from an imbalance between the secretion of parathyroid hormone and thyrocalcitonin, resulting in a net loss of calcium, and that intermittent hypercalcaemia might reverse this imbalance. This hypothesis was tested in five women with postmenopausal osteoporosis by giving 12 calcium infusions on 12 consecutive days. The bone mineral content was measured by means of osteodensitometry, which was performed at regular intervals before, during, and after the infusions. The treatment did not result in any significant alteration in bone mineral content.