Sven Ullberg

Whole-Body Autoradiography

Ever since its introduction in the early 1950s whole-body autoradiography has been used quite extensively for mapping the fate of various substances in the body, especially in the fields of pharmacology and toxicology. A detailed description of the whole-body autoradiographic technique is given. Some factors of general interest are dealt with—such as radionuclides and labeled substances, followed by a number of illustrations providing details and specific references.

Distribution of an 125I-labelled chloroquine analogue in a pregnant macaca monkey

Whole body autoradiography of a pregnant monkey (Macaca irus) of late gestation was performed 72 h after an intravenous injection of the 125I-labelled chloroquine analogue 4-(3-dimethylaminopropylamino)-7-iodoquinoline (DAPQ). The overall distribution pattern in the monkey was similar to that which was earlier observed in rodents. A few species differences, however, were found in the monkey as compared to the rodents: a high accumulation in the inner part of the adrenal cortex, a high level in the central nervous system, and generally a higher retention in the tissues. The accumulation in the adrenal cortex may be of significance for the cortisone-like effects of the 4-aminoquinolines in rheumatoid arthritis and allied conditions. The fact that no accumulation was found in the adrenal cortex of mice and rats indicates that these species may not be appropriate in studies on the mechanisms involved in the anti-inflammatory action of the 4-aminoquinolines. As was earlier observed in small rodents the melanin containing structures accumulated the drug. In both the mother and the fetus a high concentration was thus seen in the uveal tract of the eye, in the inner ear (in the stria vascularis of the cochlea and the planum semilunatum of the ampullae) and in the hair follicles. This accumulation can be related to reported disturbances--also transplacentally induced--in vision and hearing.

COMPUTER-ASSISTED QUANTIFICATION AND IMAGE PROCESSING OF WHOLE-BODY AUTORADIOGRAMS

A computerized image-processing system especially adapted for analysis of whole-body autoradiograms has been developed. It consists of commercially available standard components, including a black-and-white video camera, a microcomputer, and graphics equipment. The lower performance of the hardware has been compensated for by more flexible software. When the system was calibrated, special attention was paid to local variations in the measuring system in different parts of the picture. Utility programs for the manipulation of contrast, pseudocoloring, and image enhancement, etc., are available. Some programs have been especially designed to comply with specific problems and demands related to different autoradiographic applications. A program displaying the density histogram for an area of interest is particularly useful for the quantitation of whole-body autoradiograms. It allows the operator to select interactively a range of densities. Image elements (pixels) corresponding to the densities in this range are shown in red on the monitor, and their average true density is calculated. This procedure permits the marking and analysis of delicate structures on autoradiograms. Other programs allow a picture, stored in memory, to be rotated or translated, and two pictures to be superimposed for comparison. Various applications of using image analyses in whole-body autoradiography are presented and illustrated.

Mechanism of drug-induced chronic otic lesions. Role of drug accumulation on the melanin of the inner ear

Nachweis einer Melanin-Affinität ototoxischer Medikamente im Zusammenhang mit histopathologischen Änderungen in der Stria pigmentierter Tiere, nicht aber bei Albinos, durch Kanamycin.

The in vivo uptake of tritiated thymidine as a potential short-term test of toxic effects of polycyclic aromatic hydrocarbons in different organs

A rapid in vivo test for toxicity is described where the test substance is allowed to distribute and metabolize in the intact mouse. Quantitative data are provided on the effect of 3 different polycyclic aromatic hydrocarbons on the DNA turnover in various organs, measured as the incorporation of tritiated thymidine. In accordance with previously reported carcinogenic potencies, 7,12-dimethylbenz[alpha]anthracene (DMBA) was more potent in inhibiting the thymidine incorporation than benzo[alpha]pyrene (B[alpha]P). The inhibitory effect was most pronounced in spleen, lung, pancreas, small intestine and kidney, resulting in a decrease of incorporated activity with up to 80%. There was no evidence for the existence of specific target organs for DMBAs effects on thymidine incorporation as indicated by an inhibitory action in all organs studied. A decreased thymidine incorporation after administration of DMBA could also be demonstrated with whole-body autoradiography. The inhibitory effect of B[alpha]P was most pronounced in thymus, spleen, small intestine and testis, the average decrease of incorporated activity being more than 40% after 48 h. Contrary to the wide action of the above mentioned polycyclic aromatic hydrocarbons, an equimolar dose of anthracene lacked significant effects on the various organs.

Incorporation of [14C] nicotine into growing melanin

Abstract Foetal eye melanin in pigmented mice showed much greater accumulation of injected [ N -methyl- 14 C] nicotine- d -bitartrate than maternal eye melanin (ratio ca. 5:1). Nicotine seems to be accepted as a precursor in the formation of new melanin, due possibly to a structural resemblance to the main precursor of melanin, indole-5,6-quinone.

[10] Whole-body autoradiography

Publisher Summary The whole-body autoradiographic technique involves a series of animals, such as mice, which are injected intravenously with the same dose of a labeled compound. At intervals, the animals are rapidly frozen and sagittal sections are taken at the different levels of interest with a cryostat microtome. The sections are freeze-dried and pressed against a photographic film. After suitable exposure, section and film are separated and the film is developed. The distribution pattern of the substance and its metabolites appear on the films—the autoradiograms. The sections may be stained and mounted under a cover glass, or they may be used in their unstained state as references for the interpretation of the autoradiograms. Quantitative data concerning the radioactivity in different tissues can be obtained by impulse counting of pieces taken from the sections collected on tape, or by densitometry using an isotope scale as a reference source. Tissue pieces may also be punched out from the sections for the microseparation of metabolites. By the use of different survival times, the variation in distribution can be followed as a function of time.

Rate of Incorporation of R3hlthymidine In Various Tissues of the Mouse A basis for the evaluation of genotoxic effects of chemicals

Abstract. [3H]Thymidine has been extensively used as a selective precursor to DNA in studies on the kinetics of cell proliferation. We have become interested in measuring early inhibition of the DNA synthesis in various organs of intact animals for detecting genotoxic properties of chemicals. Such experiments should, for convenience and to achieve a large capacity, be performed in the simplest way possible.

A whole body autoradiographic study on the distribution of 14C-labelled Di-(2-ethylhexyl)phthalate in mice

Di-(2-ethylhexyl)phthalate (DEHP), a plasticizer used for polyvinylchloride polymers, has been reported to leach from blood transfusion bags and the plastic material in hemodialysis units into the blood. Phthalate esters are known to be hepatotoxic and teratogenic in experimental animals. Reports on the distribution and metabolism of DEHP indicate that the compound in largely excreted from the body within a few days. In the present investigation the distribution and tissue retention after administration of [14C]DEHP (carbonyl-14C or 2-ethylhexyl-1-14c) was studied in pregnant and non-pregnant mice with whole body autoradiography. Initially a high activity was observed in the brown fat, liver, gall bladder, intestinal contents, kidney and urinary bladder. Pretreatment with DEHP, phenobarbital sodium or 3-methylcholanthrene caused a relative increase of the activity in the brown fat, indicating that induced metabolic conversion of DEHP leads to an increased deposition of radioactivity in brown fat. After administration of DEHP (carbonyl-14C), but not DEHP (2-ethylhexyl-1-14C),marked retention was observed in the skin, cartilage and tendons. The mechanism responsible for the slow accumulation in these connective tissues is not known. In the early embryo a high concentration was observed in the neuroepithelium. This pronounced uptake may be correlated to the DEHP-induced malformations exencephaly and spina bifida observed in mice.

Differential distribution and placental transport of 2- and 3-t-[methyl-14C]butyl-4-hydroxyanisole(BHA) in pregnant mice

The placental transport and localization in fetal and maternal tissues of 14C-BHA isomers, 2-t-[methyl-14C]butyl-4-hydroxyanisole (2-BHA) and 3-t-[methyl-14C]butyl-4-hydroxyanisole (3-BHA), were studied in pregnant mice by whole-body autoradiography techniques. BHA isomers were given (iv 50 microCi/100 g as a tracer dose) to pregnant mice at Day 11 (organogenesis) and Day 18 (postorganogenesis) of gestation. Peak levels of radioactivity occurred in various tissues 1-4 hr after iv administration of both isomers. 3-BHA and its metabolites have a higher affinity to fatty tissues and livers of pregnant mice. The concentration of radiocarbon in maternal liver and brown fat following treatment with 14C-3-BHA was much higher than the radioactivity concentration in the corresponding tissues of mothers treated with 2-BHA. On the other hand, the fetal concentration of radioactivity was higher in animals treated with 2-BHA than in those treated with 3-BHA. The radioactivity derived from both isomers accumulated in the fetal gastrointestinal tract. In both groups the radioactivity accumulated in the maternal nasal cavity and mucosa and the gastrointestinal contents. At 24 hr after treatment, retention of radioactivity in maternal lungs, amniotic fluid, and fetal gastrointestinal tissues was observed. Results from this study indicate that there are differences in the magnitude and extent of placental transport of 3-BHA and 2-BHA. Differences also exist in maternal organ uptake and radioactivity distribution of both isomers. Findings from this study are consistent with pharmacological differences existing between the isomers.