Tissue Distribution Of Radioactivity Research Articles

The distribution of radio-iodinated serum albumin and low-density lipoprotein in tissues and the arterial wall

Plasma low-density lipoprotein labelled in the peptide component with radioiodine (RI-LDL) was injected into 11 patients in coma, in whom death was considered inevitable. Injected material was primarily Sf 0–9 LDL. The serum turnover of RI-LDL was followed until death of the patient. Parallel studies were carried out in another 11 subjects using radioiodinated human serum albumin (RI-HSA). Various tissues were recovered at necropsy and their radioactivity measured. The temporal pattern of radioactivity distribution in tissues was studied by comparing results from the individual patients in ascending order of the time elapsing between administration of labelled proteins and recovery of tissue. Results for RI-LDL and RI-HSA tissue to plasma radioactivity ratios were qualitatively similar.Equilibration between plasma and tissue radioactivity was most rapid in liver and spleen. Intima and inner media of aorta and coronary arteries showed rising ratios of tissue to plasma radioactivity over the 14–16-day maximum duration of these studies, and higher levels of radioactivity were reached in the arch and abdominal segments than in the thoracic aorta. Outer medial tissue/plasma ratios were lower and appeared to reach equilibrium earlier. The results show that plasma LDL peptide does enter the inner arterial wall, presumably across the intima, and that the intima may be the site of a slowly exchanging LDL pool.

Scintillation scanning of malignant melanomas with radioiodinated quinoline derivatives

Abstract The relative tissue concentrations of 14 C chloroquine were studied in 32 mice, 16 black and 16 albino, with, melanomas, at 24, 48, 72 and 96 hours after injection. An iodinated analogue of chloroquine, 4-(3-dimethylaminopropylamino)-7-iodoquinoline- 125 I (hereafter called 125 I NM-113), was synthesized, and the tissue distribution of radioactivity was then compared with that of 14 C chloroquine under similar conditions in 12 mice and in 5 hamsters with melanomas. The distribution of the same quantities of 125 I from Na 125 I was studied as a control in 12 pigmented mice with melanomas, and in 2 hamsters with melanomas. Further control animals consisted of 2 hamsters with melanomas given 100 μCi of 131 I in radioiodinated serum albumin (RISA) and in 2 hamsters 100 μCi of 197 Hg in chlormerodrin. Photoscintillation scans were performed on all hamsters with melanomas to demonstrate the location and extent of the malignant melanoma in the intact animal. The data demonstrated that a derivative of chloroquine has been synthesized and labeled with radioactive iodine without destroying the specificity of this quinoline for melanin. Furthermore, the lack of concentration of 125 I in melanin after Na 125 I and the markedly higher thyroidal 125 I concentration after Na 125 I indicate both that deiodination of 125 I NM-113 is insufficient to destroy its specificity and that the concentration of 125 I in melanin is specifically related to the labeled quinoline (NM-113). 131 I from RISA and 197 Hg from chlormerodrin also did not show specific uptake in melanin-containing tissues. The concentration ratio of 125 I from NM-113 in melanoma was sufficient in every instance to delineate the malignant melanoma by scintillation scanning.

Distribution of radioactivity in the tissues of young and adult rats after administration of tritiated Haloperidol

The tissue distribution of radioactivity after the administration of a labelled butyrophenone neuroleptic, Haloperidol- 3H, was studied in rats of various ages (1, 6, 12, 18, 24 day-old and adult). Five animals per age group were used and all were killed 30 min after intraperitoneal injection of the drug. Radioactivity was found in all tissues and was concentrated particularly in the liver, bladder, intestine, lung and kidney. The proportion of the injected radioactivity found in the brain varied with age but never exceeded 3%: it reached a maximum in 18 day-old rats, after which it decreased sharply and was less than 0.5% in the adults.

Tissue distribution and metabolism of newly absorbed vitamin A in the rat

SUMMARY Chylomicrons containing newly absorbed labeled vitamin A were injected intravenously into normal intact rats, and the tissue distribution of radioactivity was observed for several days. Chylomicrons were used so that the vitamin could be administered physiologically, in the form in which it is normally absorbed. ‘The total recovery of lipid-soluble radioactivity in the entire animal varied from 92% after 17 min to 63% after 24 hr to 56% after 6 days. At all times approximately two-thirds of the recovered radioactivity was found in the liver. Substantial amounts of radioactivity were also found in the kidneys and in the total depot fat, and small but significant amounts of labeled vitamin A were found in the plasma, small intestine, lungs, and adrenals. After 8 hr, labeled retinyl esters predominated in all tissues except plasma, with small aniounts of labeled retinol also being present. Quantitatively significant amounts of labeled retinal or retinoic acid were not observed. The composition of labeled retinyl esters was remarkable in showing a consistent predominance of saturated esters in all tissues. Marked differences were, however, seen in the relative amounts of labeled retinyl palmitate and stearate in different tissues. During the first 24 hr 3.7% of the injected radioactivity was excreted as expired COS, 3.5% was excreted as water-soluble compounds in the urine, and 8.7y0 was excreted in the bile. The biliary metabolites apparently consisted of a heterogeneous mixture of polar compounds, some of which were present as glucuronic acid conjugates.

THE METABOLISM OF FATTY ACIDS IN THE RAT. 3. ARACHIDIC ACID.

Abstract1‐C14‐Arachidic acid and 9–10‐H3‐palmitic acid in rat serum were simultaneously injected into fasted and refed male rats and the blood and tissue distribution of radioactivity were studied. The results suggest that, in spite of quantitative differences, arachidic acid enters the same principal pathways as palmitic acid. The labeled arachidic acid disappeared more slowly from the blood than did the palmitic acid. Two minutes after the injection slightly less arachidic than palmitic acid label was recovered from the whole animal. In the liver, more of the esterified arachidic acid than of the palmitic acid radioactivity was present in triglyceride and less in phospholipicl.

RENAL EXCRETION AND TISSUE DISTRIBUTION OF RADIOACTIVITY AFTER ADMINISTRATION OF TRITIUM-LABELED OXYTOCIN TO RATS.

Renal excretion and tissue distribution of radioactivity after injection of oxytocin synthesized from tritium-labeled leucine were studied in anesthetized male rats. When 0.1–15 USP units was injected intravenously during water diuresis, about 30 to 35 % of the total radioactivity was excreted in a 2-hr period with more than half of this in the first 10 min. However, only about 10% of the total avian depressor activity was excreted. Paper chromatography suggested that the urine contained a mixture of unchanged oxytocin and at least 2 metabolic products also containing the tritium label. When 10 units of radioactive oxytocin was injected into normally hydrated rats and the animals were killed 20 min later by exsanguination, kidney, liver, adrenal gland and pituitary gland had a high concentration of radioactivity. The highest concentration was found in the kidney, almost 20 times that in the blood. Radioactivity was also detected in skeletal muscle and cerebral cortex, indicating the deep and generalized p...

The tissue distribution of radioactivity following the injection of varying levels of fatty acid labeled chylomicrons in the rat.

AbstractBelfrage, P., B. Borgström and T. Olivecrona. The tissue distribution of radioactivity following the injection of varying levels of fatty acid labeled chylomicrons in the rat. Acta physiol. scand. 1963. 58. 111–123. — H3‐palmitic acid labeled chylomicrons in doses of 4–124 mg lipid were injected intravenously into rigorously carbohydrate‐fed rats. The radioactivities in blood, liver, adipose tissue, spleen, lungs, kidneys, and muscles were studied. For doses of 4 to 33 mg lipid the disappearance of label from the blood followed an exponential rate which was similar for these doses and corresponded to half‐lives of 2.2 to 3.5 minutes. The maximal radioactivities found in the liver were also similar for these doses and ranged from 40 to 51% of the injected radioactivity. For doses of 64 and 124 mg lipid the disappearance curve was more complex and the label disappeared more slowly from the blood. The maximal radioactivity found in the liver was also decreased. It is concluded that at these doses the system was overloaded. The spleen and the lungs took up significant amounts of chylomicron fatty acids as evidenced by initial peaks in the radioactivity curves for these tissues. The kidneys, the heart, and the muscles showed a slower rise of radioactivity and presumably took up mainly recirculated fatty acids. The adipose tissue also seemed to take up mainly recirculated fatty acids.

The distribution of radioactivity in tissues of the rat following the administration of a nitrogen mustard derivative; p-di-(2-chloroethyl) amino-DL-phenyl[beta-14C] alanine.

The distribution of radioactivity in tissues of the rat following the administration of a nitrogen mustard derivative; p-di-(2-chloroethyl) amino-DL-phenyl[beta-14C] alanine.

Distribution of Radioactivity in Tissues of Normal and Tumor-Bearing Mice Following Intravenous Administration of Radioiodotetrazolium Salt

Distribution of Radioactivity in Tissues of Normal and Tumor-Bearing Mice Following Intravenous Administration of Radioiodotetrazolium Salt