PubMed Health⌕ Search

Biomedical subjects

L Ahlgren

Publications and source records attributed to L Ahlgren.

31 records · Page 2Linked to original sources
PubMed1985

Excretion of radionuclides in human breast milk after the administration of radiopharmaceuticals.

The fraction of injected activity that was excreted through the breast milk of nursing mothers at different times after the injection of various radiopharmaceuticals has been measured in 21 patients. For 99mTc-labeled radiopharmaceuticals the total excreted fraction was 10% for pertechnetate and 1.5-3% for MAA, plasmin, diethylenetriaminepentaacetic acid (DTPA), and methylene diphosphonate (MDP). For [125I]hippuran and [131I]hippuran the corresponding value was 3%. For the above mentioned radiopharmaceuticals the activity concentration in the milk decreased exponentially with an effective half-life of approximately 4 hr. For chromium-51 ethylenediaminetetraacetic acid ([51Cr]EDTA) and [99mTc]RBC, much smaller amounts were excreted in the breast milk. The absorbed dose to various organs of the baby has been calculated. We conclude that when [99mTc]pertechnetate, [99mTc]MAA, [99mTc]plasmin, [125I]hippuran, or [131I]hippuran are used the child should be fed just before the administration of the radionuclide to the mother and the next three milk fractions should not be used. For [99mTc]DTPA and [99mTc]MDP as well as [51Cr]EDTA, only the first fraction should not be used. According to our earlier investigations breast feeding has to be stopped for at least 3 wk after investigations with [125I]fibrinogen.

Breast Feeding↗
PubMed1984

Lead in finger-bone analysed in vivo in active and retired lead workers.

In 75 active lead workers the median lead level in finger-bone (bone-Pb), as determined in vivo by an X-ray fluorescence method, was 43 micrograms/g (range less than 20-122). In 32 retired workers the median level was even higher, 59 micrograms/g (range less than 20-135), which indicates a slow turnover rate of lead in finger-bone. This was confirmed in 18 of the "active" workers, in whom bone-Pb was studied in connection with an exposure-free period. In spite of a significant decrease in blood-lead levels (B-Pb), no systematic change of bone-Pb occurred. There was an increase of bone-Pb with time of employment, but with a large interindividual variation. No association was found between bone-Pb and present B-Pb in the active lead workers. However, in the retired ones, B-Pb rose with increasing bone-Pb. The bone-lead pool thus causes an "internal" lead exposure.

Adult↗
PubMed1981

Cadmium in man measured in vivo by x-ray fluorescence analysis.

The sensitivity and detection limit for measurements of the concentration of cadmium in the kidney cortex of man in vivo have been investigated using the technique of X-ray fluorescence. An 11 GB1 241Am source was used to generate the characteristic K alpha X-rays of cadmium. The variation in the sensitivity for the detection of cadmium at various locations in a kidney has been studied. Because of the pronounced variation in sensitivity with depth in tissue, a measurement could be made selectively in the kidney cortex. The minimum detectable Cd concentration varies between 20 and 40 micrograms g-1 for distances between the skin and the kidney surface of 30 to 40 mm; this distance has a measured uncertainty of +/- 3 mm which gives rise to an uncertainty of +/- 30% in the estimated Cd concentration. The mean absorbed dose to the kidney during such a measurement is about 0.6 mGy. The X-ray fluorescence method is more advantageous than the alternative neutron capture gamma ray analysis technique as far as the total irradiation of the patient is concerned. The cadmium concentrations in the kidneys of five exposed persons were found to lie between 30 and 143 micrograms g-1.

Cadmium↗
PubMed1979

An X-ray fluorescence technique for in vivo determination of lead concentration in a bone matrix.

We have previously reported the in vivo detection of lead in the skeleton of man by means of X-ray fluorescence analysis using a 740 MBq 57Co source for excitation and a 1 cm(3) Ge(Li) detector for registration of the Pb Kalpha and Kbeta radiation. The varying geometry, density and atomic composition of the tissues of interest (mainly fingers) introduce several problems in estimation of the true concentration of a given element. A two-component cylindrical finger phantom was therefore constructed from silica paraffin wax and animal bone ash. The diameter of the finger bone was estimated from X-ray examinations in two orthogonal projections. The bone mineral concentration was then estimated from the quotient of the number of coherent and Compton scattered primary photons. The lead concentration in the finger bones was then derived from a measurement on a finger phantom made of silica paraffin wax and bone ash with the same size and bone mineral concentration as the real bone. The minimum detectable lead concentration in a finger bone was 14 microgram g(-1) for 15 min measuring time. The lead concentration measured in workers from a metal industry was found to be in the range of 40-100 microgram g(-1).

Bone Matrix↗
PubMed1977

Thorotrast-induced renal tumours after retrograde pyelogram.

Seven cases of 'thorotrast kidney' after retrograde pyelogram with reflux are dealt with. In five instances cancer of the kidney developed, four of them obvious renal pelvic carcinoma between 14 and 41 years after the thorotrast pyelogram. In some cases the contrast deposits were misinterpreted and in one case the follow-up was also inadequate. There is a high risk of malignancy to connection with 'thorotrast kidneys'. These cases should be follewed up with intravenous pyelogram and exfoliative cytology from renal pelvis. Provided these tests are negative, nephro-ureterectomy should be put off.

Adenocarcinoma↗
PubMed1976

X-ray fluorescence analysis of lead in human skeleton in vivo.

The lead concentration in the skeleton of living man was measured by X-ray fluorescence analysis. Five former workers from a metal industry were studied. The mean lead concentration in their skeletons was estimated to be 62 mug/g with a standard error of +/- 5 mug/g. A comparison with the "normal" skeletal concentrations of lead in people from southern Sweden showed the skeletal concentrations of the men studied to be about three to nine times higher.

Bone and Bones↗
PubMedDate not supplied

Decrease of skeletal lead levels in man after end of occupational exposure.

Lead levels in finger bone were monitored using an in vivo X-ray fluorescence technique in retired lead workers. Eight subjects followed for 2-5 yr directly after end of exposure all displayed a decrease. Their average half-time was 7 (range 3-15) yr. In a second group of six persons, followed from year 7 to year 13 after finishing lead work, a decrease was seen in all but one. The average half-time for this group was 8 (range 2 infinity) yr. The mean value for both groups was 7 yr. The results show that there is a decrease of lead in bone after the end of exposure and that it is considerably faster than estimated earlier from various data on lead metabolism.

Adult↗
PubMedDate not supplied

Lead in vertebral bone biopsies from active and retired lead workers.

Samples of vertebral bone were obtained by skeletal biopsy and lead concentrations were determined by atomic absorption spectroscopy. The median level of lead in bone in 27 active lead workers was 29 micrograms/g wet weight (range 2-155), corresponding to 370 micrograms/g calcium (range 30-1,120). In 9 retired workers, the corresponding levels were 19 micrograms/g (5-76) and 250 micrograms/g calcium (60-700); in 14 reference subjects without occupational exposure, 1.3 micrograms/g (1-4) and 13 micrograms/g calcium (8-40). The bone lead content rose with time of exposure. Comparison of levels in vertebra with those in fingerbone, as measured by in vivo x-ray fluorescence in the same subjects, strongly suggested the presence of lead pools with different kinetics. The accumulation pattern, as well as the relation between levels in vertebra and fingerbone, suggests a much shorter half-time of lead in the mainly trabecular vertebral bone as compared to the mainly cortical fingerbone. Further, there was an association between vertebral and blood lead levels in the retired workers, which shows a considerable endogenous lead exposure from the skeletal pool.

Adult↗