A Slow Component of Iodine Turnover in Athyreotic Individuals

1977 ◽  
Vol 53 (1) ◽  
pp. 81-86
Author(s):  
T. Smith ◽  
C. J. Edmonds
Keyword(s):  
Half Life ◽  
Slow Component ◽  
Biological Significance ◽  
Test Dose ◽  
Whole Body ◽  
131I Treatment ◽  
Body Tissues ◽  
Body Retention ◽  
Extractable Fraction ◽  
Slow Turnover

1. Whole-body retention and plasma values of 131I after a test dose were measured for up to 32 days in patients previously rendered athyreotic by surgery and 131I treatment for thyroid carcinoma, and who were without detectable functioning tissue at the time of study. 2. About 99·8% of the administered 131I was rapidly excreted, consistent with renal iodide excretion. The remainder (about 0·2%) was eliminated slowly, with mean half-life 15 days; we call this the slow-turnover component. 3. By the sixth day after the 131I dose, very little [131I]iodide remained in the plasma. The average protein-bound 131I was only 0·0035% of dose/l, with mean half-life 14·1 days; 90% was non-extractable in butanol. Labelled albumin accounted for about 80% of the non-extractable fraction. 4. The distribution space estimated from the slow-turnover component and protein-bound 131I was 34 1, indicating that most of the slow-turnover component is extravascular. 5. Stable potassium iodide administration, starting 2 days after giving 131I, had no observable effect on the variables measured. 6. Impairment of renal function delayed [131I]iodide excretion and increased both slow-turnover component and plasma protein-bound 131I. 7. A simple model describing iodine kinetics in athyreotic individuals is suggested. It predicts that the slow-turnover component contains only about 4 μg of iodine and, since this is distributed widely in body tissues, it is unlikely to be of biological significance.

scholarly journals Whole-Body Radioiodine Effective Half-Life in Patients with Differentiated Thyroid Cancer

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1740
Author(s):  
Michele Klain ◽  
Carmela Nappi ◽  
Marina De Risi ◽  
Leandra Piscopo ◽  
Fabio Volpe ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Half Life ◽  
Differentiated Thyroid Cancer ◽  
Multivariable Analysis ◽  
Whole Body ◽  
131I Therapy ◽  
Retention Data ◽  
Remnant Ablation ◽  
131I Treatment ◽  
Body Retention

Background: Radioactive 131I (RAI) therapy is used in patients with differentiated thyroid cancer (DTC) after total thyroidectomy for remnant ablation, adjuvant treatment or treatment of persistent disease. 131I retention data, which are used to indicate the time at which a 131I treated DTC patient can be released from the hospital, may bring some insights regarding clinical factors that prolong the length of hospitalization. The aim of this study was to investigate the 131I whole-body retention in DTC patients during 131I therapy. Methods: We monitored 166 DTC patients to follow the 131I whole-body retention during 131I therapy with a radioactivity detector fixed on the ceiling of each protected room. A linear regression fit permitted us to estimate the whole-body 131I effective half-life in each patient, and a relationship was sought between patients’ clinical characteristics and whole-body effective 131I half-life. Results: The effective 131I half-life ranged from 4.08 to 56.4 h. At multivariable analysis, longer effective 131I half-life was related to older age and extensive extra-thyroid disease. Conclusions: 131I effective half-life during 131I treatment in DTC patients is highly variable among patients and is significantly longer in older and in patients with RAI uptake in large thyroid remnants or in extrathyroidal disease that significantly prolongs the whole-body retention of 131I.

123I Scan With Whole-Body Retention Measurement at 48 Hours for Simplified Dosimetry Before 131I Treatment of Metastatic Thyroid Cancer

2020 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Jolanta M. Durski ◽  
Carrie B. Hruska ◽  
Trond V. Bogsrud ◽  
Mabel Ryder ◽  
Geoffrey B. Johnson
Keyword(s):  
Thyroid Cancer ◽  
Whole Body ◽  
131I Treatment ◽  
Body Retention ◽  
Metastatic Thyroid Cancer

Stoffwechselverhalten des anorganischen Kobalts und des in der Vitamin B12- bzw. Vitamin B12-Coenzym-Struktur organisch gebundenen Kobalts im Säugetier-Organismus

1964 ◽  
Vol 19 (11) ◽  
pp. 1032-1042 ◽  
Author(s):  
H. C. Heinrich ◽  
E. E. Gabbe
Keyword(s):  
Vitamin B12 ◽  
Half Life ◽  
Human Liver ◽  
Intramuscular Injection ◽  
Turnover Rate ◽  
Cobalt Content ◽  
Whole Body ◽  
Vitamin B ◽  
Biological Half Life ◽  
Body Retention

Chromatographically pure, vitamin B12-free 60CoCl2 as well as 60Co-vitamin B12 (60Co-cyanocobalamin and 60Co-aquocobalamin) and 60Co-vitamin B12-coenzyme (60Co-5.6-dimethylbenzimidazol-C5′-deoxyadenosyl-cobamid) were given orally and by injection in smallest amounts (10 — 100 pMol = 0.59-5.9 ng Co2®, 100 pMol = 136 ng vitamin B12 and 100 pMol = 158 ng vitamin B12-coenzyme) to female Sprague-Dawley rats.The whole body retention and excretion of the 60Co label was measured in a large volume radioactivity detector with liquid organic scintillators and 4 π-geometry. The biological half life and whole body metabolic turnover rate were calculated for the inorganic and organic cobalt from the kinetics of the 60Co whole body retention.After oral application of 100 pMol 60Co2® nearly all the 60Co is excreted already after 2 days within the faeces (90%), and the urine (15%). Only about 0.9% of the 60Co2⊕ leaves the rats with a biological half life of 18 days. After intramuscular injection of 100 pMol 60Co2⊕ about 91% of the 60Co are excreted in the urine and 10% in the faeces within four weeks. Only 4.6% of the 60Co2⊕ were eliminated with a biological half life of 28 days. The intramuscular injection of only 10 pMol 60Co2⊕ resulted in a faecal excretion of 82%, and an urinary excretion of 21% of the 60Co. A biological half life of 23 days was calculated for 8.6% of the 60Co2⊕. Inorganic cobalt is therefore practically not retained in the body and rapidly excreted mainly with the urine after injection and mainly within the faeces after oral uptake.In contrast to the inorganic cobalt a completely different metabolic behaviour is typical for the cobalt, which is incorporated in the organic structure of the vitamin B12- and vitamin B12-coenzyme molecules. This organic cobalt accumulates in the storage organs and tissues (kidney, liver etc.) after absorption as well as after injection of 100 pMol 60Co-vitamin B12 and 60Co-vitamin B12coenzyme. Only 15% of the 60Co-cyanocobalamin and 9—10% of the 60Co-aquocobalamin and 60°Covitamin B12-coenzyme are excreted within 48 hours after injection. The organ and tissue incorporated 60Co-vitamin B12 and 60Co-vitamin B12-coenzyme is metabolized with a biological half life of about 52 days. From the whole body pool size of 20 μg vitamin B12 and the biological half life a metabolic turnover rate of 0.27 μg vitamin B12/day or 1.34% of the vitamin-B12-pool per days was calculated for the whole body of the rat.The lacking organ and tissue retention of absorbed and injected 60Co2⊕ and its short biological half life in rats (if compared with the organic cobalt in the vitamin B12-structure) as well as the comparison of the total cobalt content of human liver (measured by physical techniques) with the cobalt content calculated from the vitamin B12-content of human liver (measured by microbiological assay) do not support a biological significance and function of inorganic cobalt in mammals. There is no evidence at the moment that any cobalt besides the cobalt in the vitamin B12 and vitamin B12-coenzymes is existing and biochemically active in humans or animals.

Radioimmunszintigraphie mit SPECT: Methodik, Probleme und klinische Erfahrungen

1987 ◽  
Vol 26 (05) ◽  
pp. 202-205 ◽  
Author(s):  
J. Fass ◽  
S. Truong ◽  
U. Büll ◽  
V. Schumpelick ◽  
R. Bares
Keyword(s):  
Clinical Practice ◽  
The Other ◽  
Whole Body ◽  
Blood Clearance ◽  
Planar Scintigraphy ◽  
Gastrointestinal Carcinomas ◽  
Body Regions ◽  
Other Hand ◽  
Body Retention ◽  
Klinische Erfahrungen

Radioimmunoscintigraphy (RIS) with 111ln- and 131 I-labelled monoclonal anti bodies (MAbs) against CEA and/or CA 19-9 was performed in 83 patients with various gastrointestinal carcinomas. A total of 276 body regions could be examined. The results of planar scintigraphy and SPECT were compared intraindividually. Using 111 In-labelled MAbs the sensitivity of RIS was significantly improved by SPECT (88.9 vs. 52.4% with planar scintigraphy, p <0.01). For131 l-labelled MAbs the effect was smaller (83.9 vs. 65.6% with planar scintigraphy, n.s.). This finding can be explained by different kinetics and biodistribution of the used MAb preparations.111 In-labelled MAbs with long whole-body retention and rapid blood clearance reveal ideal qualities for SPECT; on the other hand, the short whole-body retention of131 l-labelled MAbs leads to small count rates and therefore long counting times that make delayed SPECT unsuitable in clinical practice

Clearance and In Vivo Release by Heparin of Human Platelet Factor 4 (PF4) in the Rabbit

1984 ◽  
Vol 52 (02) ◽  
pp. 157-159 ◽  
Author(s):  
M Prosdocimi ◽  
N Scattolo ◽  
A Zatta ◽  
F Fabris ◽  
F Stevanato ◽  
...  
Keyword(s):  
Half Life ◽  
Human Platelet ◽  
Slow Component ◽  
Platelet Factor 4 ◽  
Platelet Factor ◽  
In Vivo Release ◽  
Partial Release ◽  
Different Doses ◽  
New Zealand Rabbits

Summary13 male New Zealand rabbits were injected with two different doses (25 μg/Kg and 100 μg/Kg) of human platelet factor 4 antigen (PF4). The disappearance of the protein was extremely fast with an half-life for the fast component of 1.07 ± 0.16 and 1.76 ± 0.11 min respectively. The half-life for the slow component, detectable only with the highest dosage, was 18.8 min.The administration of 2500 I.U. of heparin 30 min after PF4 administration induced a partial release of the injected protein and its clearance from plasma was slow, with half-life of 23.3 ± 5.9 min and 30.9 ± 2.19 min respectively.

Glucose and fatty acid metabolism in cows producing milk of low fat content

1974 ◽  
Vol 82 (1) ◽  
pp. 87-95 ◽  
Author(s):  
E. F. Annison ◽  
R. Bickerstaffe ◽  
J. L. Linzell
Keyword(s):  
Blood Flow ◽  
Milk Fat ◽  
The Body ◽  
Whole Body ◽  
Acetate Production ◽  
Entry Rate ◽  
Blood Concentrations ◽  
Body Tissues ◽  
High Starch ◽  
Starch Diet

SUMMARYThe effects of changing to a high starch: low roughage diet have been studied in two Friesian and two Jersey cows, surgically prepared for the simultaneous study of udder metabolism (arteriovenous difference x udder blood flow) and whole body turnover of milk precursors (isotope dilution).In the Friesian cows milk fat concentration was lower on the high starch diet but in the Jerseys fell only slightly in one animal. In both Friesians and in the one Jersey these changes were accompanied by an increase in total rumen VFA concentration. Rumen acetate concentration did not change but propionate doubled. Thus this confirms that the usually reported fall in ‘acetate:propionate ratio’ is due to a rise in propionate production rather than due to a fall in acetate production.There were significant falls in the blood concentrations of acetate and β-hydroxy-butyrate. The rate of extraction by the udder of acetate and β-hydroxybutyrate did not change but triglyceride extraction fell. Therefore since udder blood flow did not alter the uptake of all three fat precursors fell.The entry rate of glucose into the circulation and its contribution to total body CO2 increased. The entry rate and contribution to CO2 of acetate decreased but this was probably mainly due to a fall in endogenous acetate production by the body tissues. Plasma FFA concentration showed little change but the entry rate of palmitate fell on the high starch diet. There was also an increased proportion of unsaturated and trans fatty acids in the plasma and milk triglycerides.

scholarly journals Improved zinc and iron absorption from breakfast meals containing malted oats with reduced phytate content

1996 ◽  
Vol 76 (5) ◽  
pp. 677-688 ◽  
Author(s):  
Marie Larsson ◽  
Lena Rossander-Hulthén ◽  
Brittmarie Sandström ◽  
Ann-Sofie Sandberg
Keyword(s):  
Iron Absorption ◽  
Human Subjects ◽  
Vulnerable Groups ◽  
Whole Body ◽  
Absolute Amount ◽  
Average Increase ◽  
Mineral Deficiency ◽  
Breakfast Meal ◽  
Body Retention ◽  
Phytate Content

The absorption of Zn or Fe from breakfast meals containing oat porridge prepared from malted and soaked oats and a control porridge made from untreated oats was measured in human subjects. The effect on Zn and Fe absorption of reducing the phytate content of oat-porridge meals was examined in each subject by extrinsic labelling of porridge with 65Zn and of bread rolls with 55Fe and 59Fe, and measuring whole-body retention and the erythrocyte uptake of isotopes. Each experiment comprised nine to ten subjects. The absorption of Zn from malted-oat porridge with a phytate (inositol hexaphosphate) content of 107 μmol was 18·3%, and significantly higher (P < 0·05) than from the control porridge containing 432 μmol phytate (11·8%). Fe absorption from the meal containing malted-oat porridge with 107 μmol phytate (Expt 2) was also significantly improved (P < 0·05) compared with that from the meal containing control porridge with 437 μmol phytate. The average increase in Fe absorption was 47%, or from 4·4 to 6·0%. In the breakfast meal containing malted porridge with 198 μmol phytate (Expt 3) the increase in Fe absorption was not significantly improved. Even though the phytate content was reduced to a greater extent in Expt 3 than Expt 2, the average increase in Fe absorption in Expt 3 was only 25% more than that from the meal containing control porridge (with 599 μmol phytate), depending on the higher absolute amount of phytate. In conclusion, an improvement in Zn and Fe absorption from oat products can be achieved by practising malting and soaking in the processing of oats. This may be of importance in the prevention of mineral deficiency in vulnerable groups.

Rate of loss of radioiron from mouse and man

1960 ◽  
Vol 198 (4) ◽  
pp. 784-786 ◽  
Author(s):  
John D. Bonnet ◽  
Alan L. Orvis ◽  
Albert B. Hagedorn ◽  
Charles A. Owen
Keyword(s):  
Life Span ◽  
Half Life ◽  
Whole Body ◽  
Entire Body ◽  
Rapid Loss ◽  
Male And Female ◽  
Female Mice ◽  
Steady Rate ◽  
Normal Man ◽  
The Difference

Forty-two male and female mice, 8 weeks old, were given radioiron (Fe59) in doses of 0.006–0.1 µc, containing 0.013–0.17 µg of iron, by intraperitoneal or intravenous routes. Assays of the radioactivity of the whole body revealed an initial rapid loss of Fe59 (15–20%) lasting about 6 days. Thereafter the Fe59 left the mice at a steady rate of 0.39%/day (half-life 180 days). One 34-year-old normal man was given 10.6 µc of Fe59, containing 8.2 µg of iron, intravenously. Based on counts from the entire body, the biologic rate of loss of the Fe59 was about 0.14%/day (half-life 500 days), and there was little or no initial loss such as occurred in the mouse. The Fe59 in the circulating erythrocytes was essentially unchanged for the first 3 months. It then fell to a new level of about 90% of the previous one; the mid-point of the fall was about 120 days after the administration of the radioiron. The difference in the rates of loss of radioiron from mice and man seems to be related primarily to the life span of the circulating red cells.

Gastrointestinal iron and cobalt absorption and iron status in young rats and guinea pigs

1995 ◽  
Vol 14 (12) ◽  
pp. 949-954 ◽  
Author(s):  
Gpl Naylor ◽  
JD Harrison
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
Iron Status ◽  
Age Groups ◽  
Gastrointestinal Absorption ◽  
Whole Body ◽  
Suckling Period ◽  
Young Rats ◽  
Body Retention ◽  
Different Ages

The gastrointestinal absorption of Fe and Co by rats and guinea pigs of different ages was measured by comparing the whole-body retention of 59Fe and 57Co after oral and intraperitoneal administrations. The age-groups studied included newborn, weanlings and adults. The absorption of both Fe and Co decreased markedly with age in both rats and guinea pigs. In the rat, absorption remained ele vated during the suckling period, while in the guinea pig absorption decreased markedly during suckling. In both species, Fe and Co absorption were similar, and remained elevated above adult values for some time after weaning. The generally greater absorption of Fe and Co by rats than by guinea pigs and the longer duration of maximal absorp tion in the rats may have involved differences in Fe status in the two species and differences in the timing of gut mat uration.

Influence of endurance training on muscle [PCr] kinetics during high-intensity exercise

2007 ◽  
Vol 293 (1) ◽  
pp. R392-R401 ◽  
Author(s):  
Andrew M. Jones ◽  
Daryl P. Wilkerson ◽  
Nicolas J. Berger ◽  
Jonathan Fulford
Keyword(s):  
Endurance Training ◽  
High Intensity ◽  
Slow Component ◽  
Knee Extension ◽  
High Intensity Exercise ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Exercise Tests ◽  
Before And After ◽  
Knee Extension Exercise

We hypothesized that a period of endurance training would result in a speeding of muscle phosphocreatine concentration ([PCr]) kinetics over the fundamental phase of the response and a reduction in the amplitude of the [PCr] slow component during high-intensity exercise. Six male subjects (age 26 ± 5 yr) completed 5 wk of single-legged knee-extension exercise training with the alternate leg serving as a control. Before and after the intervention period, the subjects completed incremental and high-intensity step exercise tests of 6-min duration with both legs separately inside the bore of a whole-body magnetic resonance spectrometer. The time-to-exhaustion during incremental exercise was not changed in the control leg [preintervention group (PRE): 19.4 ± 2.3 min vs. postintervention group (POST): 19.4 ± 1.9 min] but was significantly increased in the trained leg (PRE: 19.6 ± 1.6 min vs. POST: 22.0 ± 2.2 min; P < 0.05). During step exercise, there were no significant changes in the control leg, but end-exercise pH and [PCr] were higher after vs. before training. The time constant for the [PCr] kinetics over the fundamental exponential region of the response was not significantly altered in either the control leg (PRE: 40 ± 13 s vs. POST: 43 ± 10 s) or the trained leg (PRE: 38 ± 8 s vs. POST: 40 ± 12 s). However, the amplitude of the [PCr] slow component was significantly reduced in the trained leg (PRE: 15 ± 7 vs. POST: 7 ± 7% change in [PCr]; P < 0.05) with there being no change in the control leg (PRE: 13 ± 8 vs. POST: 12 ± 10% change in [PCr]). The attenuation of the [PCr] slow component might be mechanistically linked with enhanced exercise tolerance following endurance training.

Sign in / Sign up

Export Citation Format

Share Document