A COMPARISON BETWEEN THE UPTAKES OF RADIOACTIVE PERCHLORATE AND IODIDE BY RAT AND GUINEA-PIG THYROID GLANDS

1969 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. Y. CHOW ◽  
L. R. CHANG ◽  
M. S. YEN
Keyword(s):  
Plasma Concentration ◽  
Marked Effect ◽  
Specific Activity ◽  
Chronic Administration ◽  
Anion Transport ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Glands ◽  
Stable Anion ◽  
Dose Levels ◽  
Concentration Ratios

SUMMARY Previous studies indicated that 36Cl-labelled perchlorate is concentrated by rat and rabbit thyroid gland. However, the extent of concentration of radioactive perchlorate in the gland was much less than that of iodide. Since perchlorate itself has a marked effect on anion transport in the thyroid and the specific activity of available [36C]perchlorate is very low, the stable anion as a carrier present in the injected radioactive perchlorate solution may affect the uptake of this radioactive compound by the gland. In this study, radioactive solutions of perchlorate and iodide containing different amounts of stable perchlorate or iodide (dosages ranged from 0·005 to 5 m-equiv./kg. body weight) were injected into groups of rats and guineapigs, and the thyroid: plasma concentration ratios of radioactive perchlorate and iodide were calculated and compared. These experiments were also repeated in animals pretreated with thyroid-stimulating hormone (TSH), after chronic administration of propylthiouracil (PTU), as well as in hypophysectomized animals. At the same dose levels of perchlorate, there was no difference in thyroid: plasma concentration ratios of radioactive perchlorate and iodide in control rats and guinea-pigs or in treated ones.

Solute concentrations of the pulmonary epithelial lining fluid of anesthetized rats

1990 ◽  
Vol 68 (1) ◽  
pp. 275-281 ◽  
Author(s):  
R. M. Effros ◽  
N. H. Feng ◽  
G. Mason ◽  
K. Sietsema ◽  
P. Silverman ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Bronchoalveolar Lavage ◽  
Rat Model ◽  
Total Protein ◽  
Specific Activity ◽  
Epithelial Lining ◽  
Plasma Urea ◽  
Epithelial Lining Fluid ◽  
Plasma Urea Concentration ◽  
Concentration Ratios

Uncertainty persists concerning the best method of estimating the volume and solute concentrations of the pulmonary epithelial lining fluid (ELF) recovered during bronchoalveolar lavage (BAL). In the present study, measurements were made of the BAL-to-plasma concentration ratios of a variety of solutes in an anesthetized rat model. One minute after an intravenous injection of labeled Na+ and urea, 5 ml of isotonic mannitol, saline, or glucose were injected into the trachea and an initial aliquot of the BAL was immediately removed. Initial BAL-to-plasma concentration ratios of urea, Na+, Cl-, Ca2+, and total protein were similar (ranging from 0.013 to 0.017) after BAL with mannitol, but albumin and transferrin ratios were approximately 60% lower and K+ ratios were five times greater. Lavage with saline yielded BAL-to-plasma urea concentration ratios similar to those obtained with mannitol lavage. The BAL-to-plasma specific activity of urea was about twice that of Na+, indicating that urea diffused into the ELF more rapidly than Na+ during the 70 s that elapsed between the time the radioactive urea and Na+ were injected into the circulation and the time when lavage was complete. Subsequent lavage samples also indicated that urea rapidly diffuses into the fluid-filled lungs. These experiments suggest that isotonic mannitol may be a useful solution for lavage, because it allows use of Na+ and perhaps Cl- as additional indicators of ELF dilution by BAL.(ABSTRACT TRUNCATED AT 250 WORDS)

The Natural Radioactivity in Food: A Comparison Between Different Feeding Regimes

2019 ◽  
Vol 15 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Francesco Caridi ◽  
Santina Marguccio ◽  
Alberto Belvedere ◽  
Maurizio D`Agostino ◽  
Giovanna Belmusto
Keyword(s):  
Vegetable Oils ◽  
Natural Radioactivity ◽  
Specific Activity ◽  
Mean Value ◽  
Vegetable Food ◽  
Fish Samples ◽  
Feeding Regimes ◽  
Italian Origin ◽  
Dose Levels

Background: In this article a comprehensive study was carried out for the determination of natural radioactivity in animal and vegetable food (meat, fish, milk and derivates, legumes, cereals and derivates, fruit, hortalizas, vegetables, vegetable oils) typical of different feeding regimes, for the age category higher than 17 years. Methods: A total of eighty-five samples of Italian origin, coming from large retailers during the years 2014, 2015 and 2016, were analyzed through HPGe gamma spectrometry. Results: The specific activity of 40K was investigated and its mean value was found to be: (106.3 ± 6.9) Bq/kg for bovine, swine and sheep meat; (116.5 ± 9.7) Bq/kg for fish; (52.9 ± 3.1) Bq/kg for milk and derivates; (271.9 ± 16.7) Bq/kg for legumes; (67.2 ± 4.7) Bq/kg for cereals and derivates; (52.7 ± 4.4) Bq/kg for fruit; (72.9 ± 5.6) Bq/kg for hortalizas; (83.9 ± 6.5) Bq/kg for vegetables; lower than the minimum detectable activity for vegetable oils. For animal food the highest mean 40K activity concentration was found in fish samples; for vegetable food the highest one was detected in legumes. Conclusion: The evaluation of dose levels due to the food ingestion typical of Mediterranean, Vegetarian and Vegan diets was performed. The annual effective dose was found to be 0.16 mSv/y, 0.41 mSv/y and 0.54 mSv/y, respectively.

Infants Diagnosed with Athyreosis on Scintigraphy May Have a Gland Present on Ultrasound and Have Transient Congenital Hypothyroidism

2021 ◽  
pp. 1-8
Author(s):  
Niamh McGrath ◽  
Colin Patrick Hawkes ◽  
Stephanie Ryan ◽  
Philip Mayne ◽  
Nuala Murphy
Keyword(s):  
Thyroid Gland ◽  
Congenital Hypothyroidism ◽  
Thyroid Tissue ◽  
Thyroid Stimulating Hormone ◽  
Thyroid Ultrasound ◽  
Free T4 ◽  
Median Serum ◽  
Thyroid Glands ◽  
Rule Out

Scintigraphy using technetium-99m (<sup>99m</sup>Tc) is the gold standard for imaging the thyroid gland in infants with congenital hypothyroidism (CHT) and is the most reliable method of diagnosing an ectopic thyroid gland. One of the limitations of scintigraphy is the possibility that no uptake is detected despite the presence of thyroid tissue, leading to the spurious diagnosis of athyreosis. Thyroid ultrasound is a useful adjunct to detect thyroid tissue in the absence of <sup>99m</sup>Tc uptake. <b><i>Aims:</i></b> We aimed to describe the incidence of sonographically detectable in situ thyroid glands in infants scintigraphically diagnosed with athyreosis using <sup>99m</sup>Tc and to describe the clinical characteristics and natural history in these infants. <b><i>Methods:</i></b> The newborn screening records of all infants diagnosed with CHT between 2007 and 2016 were reviewed. Those diagnosed with CHT and athyreosis confirmed on scintigraphy were invited to attend a thyroid ultrasound. <b><i>Results:</i></b> Of the 488 infants diagnosed with CHT during the study period, 18/73 (24.6%) infants with absent uptake on scintigraphy had thyroid tissue visualised on ultrasound (3 hypoplastic thyroid glands and 15 eutopic glands). The median serum thyroid-stimulating hormone (TSH) concentration at diagnosis was significantly lower than that in infants with confirmed athyreosis (no gland on ultrasound and no uptake on scintigraphy) (74 vs. 270 mU/L), and median free T4 concentration at diagnosis was higher (11.9 vs. 3.9 pmol/L). Six of 10 (60%) infants with no uptake on scintigraphy but a eutopic gland on ultrasound had transient CHT. <b><i>Conclusion:</i></b> Absent uptake on scintigraphy in infants with CHT does not rule out a eutopic gland, especially in infants with less elevated TSH concentrations. Clinically, adding thyroid ultrasound to the diagnostic evaluation of infants who have athyreosis on scintigraphy may avoid committing some infants with presumed athyreosis to lifelong levothyroxine treatment.

Safety, Tolerability and Pharmacokinetics of BIBN 4096 BS, the First Selective Small Molecule Calcitonin Gene-Related Peptide Receptor Antagonist, Following Single Intravenous Administration in Healthy Volunteers

Cephalalgia ◽  
2004 ◽  
Vol 24 (8) ◽  
pp. 645-656 ◽  
Author(s):  
M Iovino ◽  
U Feifel ◽  
C-L Yong ◽  
J-M Wolters ◽  
G Wallenstein
Keyword(s):  
Plasma Concentration ◽  
Receptor Antagonist ◽  
Small Molecule ◽  
Intravenous Administration ◽  
Calcitonin Gene Related Peptide ◽  
Related Peptide ◽  
Concentration Time ◽  
Calcitonin Gene ◽  
Dose Levels ◽  
Single Intravenous Administration

BIBN 4096 BS ([R-(R∗,S∗)]-N-[2-[[5-amino-1-[[4-(4-pyridinyl)-1-piperazinyl]carbonyl] pentyl]amino]-1-[(3,5-dibromo-4-hydroxyphenyl)methyl]-2-oxoethyl]-4-(1,4-dihydro-2-oxo-3(2H)-quinazolinyl)-,1-piperidinecarboxamide) is the first selective, highly potent, small molecule, nonpeptide calcitonin gene-related peptide (CGRP) receptor antagonist, which has been developed for the treatment of acute migraine. The objective of this study was to obtain information on the safety, tolerability and pharmacokinetics of BIBN 4096 BS following single intravenous administration of rising doses (0.1, 0.25, 0.5, 1, 2.5, 5 and 10 mg) in 55 healthy male and female volunteers. The study was of single-centre, double-blind (within dose levels), placebo-controlled, randomized, single rising dose design. Blood pressure, pulse rate, respiratory rate, ECG, laboratory tests and forearm blood flow did not reveal any clinically relevant, drug-induced changes. Sixteen adverse events (AEs) were reported by eight of 41 volunteers after BIBN 4096 BS compared to five AEs reported by four of 14 volunteers after placebo. Approximately two-thirds of all AEs related to active treatment occurred at the highest dose of 10 mg. At this dose level, all AEs were confined to the three BIBN 4096 BS-treated females, and consisted mainly of transient and mild paresthesias. Paresthesias were the single most frequent AE, whereas fatigue was the AE which occurred in the highest number of subjects. Only two AEs were of moderate intensity, all remaining AEs were of mild intensity. No serious AEs were reported. The local tolerability after intravenous administration was good. In summary, intravenously administered BIBN 4096 BS revealed a very favourable safety profile over the dose range tested in both genders. Generally well tolerated at all dose levels, it was of satisfactory tolerability in female subjects at the highest dose of 10 mg. The plasma concentration-time courses of BIBN 4096 BS showed multicompartmental disposition characteristics. Mean maximum concentration (Cmax) values appeared to be dose-proportional. Based on the results from the two high dose levels (5 and 10 mg) with sufficient individual subject data, BIBN 4096 BS exhibited a total plasma clearance (CL) of approximately 12 l/h and an apparent volume of distribution at steady state (Vss) of approximately 20 l, resulting in a terminal half-life (t1/2) of approximately 2.5 h. Inter-individual variability was moderate with a coefficient of variation of approximately 45% based on the area under the plasma concentration-time curve (AUC) values. The mean renal clearance (CLR) was approximately 2 l/h, suggesting that renal excretion plays only a minor role in the elimination of unchanged BIBN 4096 BS.

scholarly journals Low Dose Ketoconazole Therapy and Thyroid Functions in Rats

2002 ◽  
Vol 45 (4) ◽  
pp. 177-179 ◽  
Author(s):  
Hüseyin Çaksen ◽  
Ahmet Tutuş ◽  
Selim Kurtoğlu ◽  
Figen Öztürk ◽  
Yüksel Okumuş ◽  
...  
Keyword(s):  
Thyroid Gland ◽  
Epithelial Cells ◽  
Low Dose ◽  
Thyroid Stimulating Hormone ◽  
Control Group ◽  
Histopathological Analysis ◽  
Study Group ◽  
Thyroid Function Tests ◽  
End Of Treatment ◽  
Thyroid Glands

To determine whether low dose ketoconazole (KTZ) has antithyroid action, we studied thyroid function tests in the 13 rats treated with KTZ (20 mg/kg twice daily) for thirty days. Serum triiodothyronine and thyroxine levels were decreased (P <0.05) and serum thyroid-stimulating hormone levels were mildly increased (P >0.05) at the end of treatment. Histopathological analysis of the thyroid glands demonstrated an increase in cylindrical cells in study group, but the epithelial cells were mainly cubical in control group. These findings showed that low dose KTZ had antithyroid effect in rats. The responsible mechanisms may be direct effect of the drug on thyroid gland.

Clinical and Morphologic Findings of Familial Goiter in Bongo Antelope (Tragelaphus eurycerus)

1995 ◽  
Vol 32 (3) ◽  
pp. 242-249 ◽  
Author(s):  
C. A. Schiller ◽  
R. J. Montali ◽  
S. Doi ◽  
E. F. Grollman
Keyword(s):  
Thyroid Stimulating Hormone ◽  
Normal Serum ◽  
Follicular Epithelium ◽  
Adult Onset ◽  
Human Beings ◽  
Cyclic Activity ◽  
Congenital Goiter ◽  
Thyroid Glands ◽  
Serum T3 ◽  
Familial Goiter

Inherited defects of thyroglobulin synthesis resulting in congenital goiter are well described in certain breeds of domestic ungulates and in human beings. Goiter associated with synthesis of an abnormal thyroglobulin and the presence of thyroidal albumin was identified in five closely related bongo antelopes ( Tragelaphus eurycerus). The goiter had an adult onset, and the affected bongos appeared to remain euthyroid with normal serum T3 and T4 values, normal serum cholesterol concentrations, and nonelevated concentrations of circulating thyroid stimulating hormone (TSH). Goitrous bongos had significant reproductive difficulties, including reduced cyclic activity and prolonged gestations, but were otherwise normal. Over the course of the disease, the thyroid glands greatly enlarged (up to 10 × 20 cm) and became polycystic. Microscopically, there was an admixture of giant colloid-filled follicles and follicles of normal size lined with variable follicular epithelium ranging from squamoid to mildly to moderately hyperplastic. The pathogenesis of goiter in the bongo may reflect a mixture of genetic predisposition coupled with environmental factors, including a period of exposure to a goitrogen.

DRUG INTERACTIONS—PART III

PEDIATRICS ◽  
1972 ◽  
Vol 50 (3) ◽  
pp. 489-490
Author(s):  
Lester F. Soyka
Keyword(s):  
Enzyme Induction ◽  
Specific Activity ◽  
Smooth Endoplasmic Reticulum ◽  
Chronic Administration ◽  
Concurrent Administration ◽  
Protein Mass ◽  
Carcinogenic Potential ◽  
Activity Of Enzymes ◽  
Practice Activity ◽  
Cellular Components

ENZYME induction is defined as an increase in the specific activity of enzymes which metabolize foreign substances (e.g., drugs, chemicals, and insecticides) and certain endogenous compounds (e.g., steroids and fatty acids). In practice, activity, rather than actual enzyme protein mass relative to structural cellular components, is usually determined. Most of the drug-metabolizing (microsomal) enzymes are in the liver; however, lesser activity is found in the skin, placenta, kidney, lung, etc., and induction in these organs has been demonstrated. In 1956 Conney et al.1 observed that chronic administration of 3-methylcholanthrene (3-MC) caused an increase in its own rate of metabolism, thereby decreasing its carcinogenic potential. Remmer and Merker2 found that the tolerance of animals to chronic barbiturate administration was partly due to an increased rate of metabolic inactivation, and that hypertrophy of the smooth endoplasmic reticulum of hepatocytes resulted from such treatment. Subsequent investigations have shown that more than 200 drugs and chemicals cause enzyme induction in animals3 and several of these are known to be active in man. Inducers are of three types: small organic molecules, e.g., phenobarbital; chlorinated hydrocarbons, e.g., DDT; and polycydic hydrocarbons, e.g., the environmental polycyclic carcinogens 3-MC and 3,4 benzpyrene. Many clinical reports indicate that important modifications of a drug's effectiveness and safety may arise through induction during continued administration, or through concurrent administration of other drugs. These modifications are: (1) a decrease in effectiveness from acceleration of the rate of inactivation and excretion, (2) an increase in effectiveness from an increase in the rate of biotransformation to an active metabolite, or (3) either of these arising from the action of a previously or concurrently administered inducing drug.

Renal excretion of radiofluoride in the dog

1960 ◽  
Vol 198 (4) ◽  
pp. 829-832 ◽  
Author(s):  
Curtis H. Carlson ◽  
W. D. Armstrong ◽  
Leon Singer ◽  
Lerner B. Hinshaw
Keyword(s):  
Plasma Concentration ◽  
Glomerular Filtration ◽  
Renal Excretion ◽  
Urine Volume ◽  
Urine Concentration ◽  
Tubular Reabsorption ◽  
Carrier Free ◽  
Renal Clearances ◽  
Concentration Ratios

Renal clearances of continuously infused radiofluoride were measured in 10 dogs in which a large part of the skeleton had been excluded from the system in order to produce a more constant plasma radiofluoride concentration. The results were evaluated to describe the factors of glomerular filtration and tubular reabsorption of fluoride under several conditions. The animals that received carrier-free radiofluoride infusions excreted urine with a mean radiofluoride concentration 3.4–14.5 times that of the plasma. The urine-to-plasma concentration ratios obtained with animals given a load of stable fluoride was 13.5–29.6. An increased urine volume resulted in a decreased tubular reabsorption of fluoride and the clearance was increased. Chlorothiazide increased radiofluoride excretion but decreased the urine concentration. The radiofluoride clearances were always less than the creatinine clearances but were 7.8–179 times the chloride clearances. The effect of chlorothiazide was to decrease the ratio of fluoride to chloride clearance by increasing chloride clearance more than fluoride clearance.

Augmentation of mouse thyroid iodide pump activity after withdrawal of propylthiouracil

1959 ◽  
Vol 196 (5) ◽  
pp. 981-982 ◽  
Author(s):  
H. J. Lipner ◽  
Billie P. Wagner ◽  
Harold P. Morris
Keyword(s):  
Thyroid Function ◽  
Specific Activity ◽  
Chronic Administration ◽  
Total Activity ◽  
Pump Activity ◽  
Mouse Thyroid

The chronic administration of propylthiouracil for 16–30 days to mice resulted in either no increase or depression in the specific activity of the thyroid iodide pump. Within 24 hours after the withdrawal of propylthiouracil from the diet there occurred an augmentation of the specific activity of the iodide pump. The total activity of the thyroid pump behaved in a similar manner. The disassociation of pump activity from growth suggests that in the mouse these parameters of thyroid function are independent processes.

Sign in / Sign up

Export Citation Format

Share Document