Toxicity of Leucaena leucocephala in ruminants: the effect of supplemental thyroxine on goats fed on a sole diet of Leucaena

1983 ◽  
Vol 34 (6) ◽  
pp. 791 ◽  
Author(s):  
RG Megarrity ◽  
RJ Jones
Keyword(s):  
Zinc Deficiency ◽  
Body Condition ◽  
Leucaena Leucocephala ◽  
Normal Serum ◽  
Toxic Effects ◽  
Thyroid Status ◽  
Serum Thyroxine ◽  
Serum T4 ◽  
Thyroid Hyperplasia

Daily injections of thyroxine were ineffective in overcoming the toxic effects of feeding Leucaena to goats. The treated goats did not differ from the controls in liveweight change or body condition over the 15 weeks of feeding Leucaena and both groups of animals developed oesophageal lesions. Treated animals maintained normal serum thyroxine (T4) and triiodothyronine (T3) levels and did not exhibit the thyroid hyperplasia of the controls. An increase in the serum T4 and T3 levels of three of the control animals after 5 weeks of feeding was associated with declining mimosine concentration in the feed and the ability of the hyperplastic thyroids to produce sufficient T4. Serum analyses suggested zinc deficiency in the control animals, associated with their low thyroid status. It was concluded that the goitrogenicity of 3-hydroxy-4(1H)-pyridone (DHP) is only partly responsible for the toxicity of Leucaena to ruminants, and that the low feed intakes and low liveweight gains are related to other effects of DHP. The evidence for extra-ruminal metabolism of DHP is discussed.

scholarly journals Ratio of Thyroxine to Thyroxine-Binding Globulin

1981 ◽  
Vol 18 (2) ◽  
pp. 93-96 ◽  
Author(s):  
C F Cusick
Keyword(s):  
Reference Range ◽  
False Positives ◽  
Patient Data ◽  
Reference Ranges ◽  
Thyroid Status ◽  
False Negatives ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Protein Levels ◽  
Serum T4

The thyroxine:thyroxine-binding globulin ratio in serum (T4:TBG) has been proposed as a measure of thyroid status unaffected by altered binding protein levels. Here 320 apparently euthyroid patients are used to derive euthyroid ranges for serum thyroxine concentrations at specific TBG levels. These ranges are compared with those predicted by a T4:TBG reference range derived from the same patient data. The comparison suggests that the ratio would give false positives for hyperthyroidism at low TBG levels and false negatives at high TBG levels. To overcome this the use of graphical reporting of results or the relation of patient results to empirical reference ranges appropriate to the TBG level is suggested.

EVALUATION OF A SIMPLIFIED METHOD FOR DETERMINING SERUM THYROXINE BY COMPETITIVE PROTEIN BINDING ANALYSIS

1970 ◽  
Vol 64 (4) ◽  
pp. 630-636 ◽  
Author(s):  
Stephen C. Thorson ◽  
Ronald Tsujikawa ◽  
James L. Brown ◽  
Robert T. Morrison ◽  
Hamish W. McIntosh
Keyword(s):  
Protein Binding ◽  
Clinical Application ◽  
Thyroid Status ◽  
Serum Thyroxine ◽  
Binding Analysis ◽  
Simplified Method ◽  
Competitive Protein Binding ◽  
Hypothyroid Patients

ABSTRACT Serum thyroxine concentrations were determined in 66 euthyroid, 30 hyperthyroid and 13 hypothyroid patients using both the established Murphy method and a simplified method of competitive protein binding analysis. A diagnosis compatibility of 96% was found with both methods indicating that the simplified method has comparable clinical application as an initial screen of thyroid status.

TRH (Thyroid-Releasing Hormone) Tests

1984 ◽  
Vol 6 (6) ◽  
pp. 189-190
Keyword(s):  
Binding Proteins ◽  
Elevated Serum ◽  
Graves Disease ◽  
Base Line ◽  
Trh Test ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
Free Thyroxine Index ◽  
Serum T4 ◽  
Line Test

I have read with great interest "Goiter in Children" by Foley (PIR 1984;5:259). The author stated: "In patients with thyromegaly and mild symptoms of hyperthyroidism, a TRH test will help to discriminate hyperthyroxemia secondary to increased or abnormal serum thyroxine binding proteins from early Graves disease, factitious hyperthyroidism, toxic thyroiditis, and TSH-mediated hyperthyroidism." I would suggest the use of a triiodothyronine (T3) resin uptake as a base-line test. An elevated serum thyroxine (T4) value in conjunction with a diminished T3 resin uptake suggests thyroxine-binding globulin (TBG) excess, which can be confirmed by specific quantitation of TBG. Patients with familial dysalbuminemic hyperthyroxinemia (FDH) have elevated levels of serum T4 and free thyroxine index (FT4l) values but normal T3 resin uptake and TBG levels.

Binding of labeled thyroxin analog to serum proteins evaluated after radioimmunoassay of free thyroxin.

1989 ◽  
Vol 35 (3) ◽  
pp. 475-477 ◽  
Author(s):  
G Arevalo
Keyword(s):  
Serum Proteins ◽  
Equilibrium Dialysis ◽  
Normal Serum ◽  
Thyroid Status ◽  
Nonthyroidal Illness ◽  
Serum Pool ◽  
Normal Individuals ◽  
Ambulatory Patients ◽  
One Step

Abstract In ambulatory patients, assay of free thyroxin (FT4) in serum correlates well with thyroid status and with results obtained by equilibrium dialysis. The validity of FT4 results has been questioned mainly in euthyroid patients with altered concentrations of thyroid hormone-binding proteins, as in nonthyroidal illness, hereditary analbuminemia, familial dysalbuminemic hyperthyroxinemia (FDH), and the presence of iodothyronine-binding antibodies. I present here a study of the binding of [125I]T4-derivative to serum proteins in the supernate, which is ordinarily discarded after determination of FT4 by one-step radioimmunoassay with dextran-coated charcoal used to separate the free and bound fractions. The results are expressed as a ratio, with results for a normal serum pool as reference. The average ratio was high in hyperthyroid subjects, 1.26 (SD 0.12, n = 25), and in hypoalbuminemia, 1.20 (SD 0.10, n = 15), and low in FDH, 0.62 (SD 0.11, n = 9), and hypothyroid subjects, 0.90 (SD 0.06, n = 20). In normal individuals it was 0.98 (SD 0.05, n = 30). Determination of the analog-binding rate complements the FT4 result and allows for the recognition of cases with abnormal binding by serum proteins, without recourse to other tests recommended for thyroid-function studies.

scholarly journals Mice with Impaired Extrathyroidal Thyroxine to 3,5,3′-Triiodothyronine Conversion Maintain Normal Serum 3,5,3′-Triiodothyronine Concentrations

Endocrinology ◽  
2007 ◽  
Vol 148 (3) ◽  
pp. 954-960 ◽  
Author(s):  
Marcelo A. Christoffolete ◽  
Rafael Arrojo e Drigo ◽  
Fernanda Gazoni ◽  
Susana M. Tente ◽  
Vanessa Goncalves ◽  
...  
Keyword(s):  
Biological Effects ◽  
Elevated Serum ◽  
Normal Growth ◽  
Normal Serum ◽  
C3h Mice ◽  
Serum T3 ◽  
Serum T4 ◽  
Hormone Homeostasis ◽  
Type 3

For T3 to mediate its biological effects, the prohormone T4 must be activated by removal of an outer-ring iodine by the type 1 or 2 deiodinases (D1 and D2) with approximately 60% of the daily T3 production in rodents being produced extrathyroidally through this pathway. To further define the role of these enzymes in thyroid hormone homeostasis, we backcrossed the targeted disruption of the Dio2 gene into C3H/HeJ (C3H) mice with genetically low D1 expression to create the C3H-D2KO mouse. Remarkably, these mice maintain euthyroid serum T3 levels with normal growth and no decrease in expression of hepatic T3-responsive genes. However, serum T4 is increased 1.2-fold relative to the already elevated C3H levels, and serum TSH is increased 1.4-fold. Despite these increases, thyroidal 125I uptake indicates no difference in thyroidal activity between C3H-D2KO and C3H mice. Although C3H-D2KO hepatic and renal D1 activities were well below those observed in wild-type mice (∼0.1-fold for both), they were 8-fold and 2-fold higher, respectively, relative to C3H mice. Thyroidal D1 and cerebral cortical type 3 deiodinase activity were unchanged between C3H-D2KO and C3H mice. In conclusion, C3H-D2KO mice have notably elevated serum T4 levels, and this, in conjunction with residual D1 activity, is likely an important role in the maintenance of euthyroid serum T3 concentrations.

scholarly journals Accuracy and Standardisation of Serum Thyroxine Assays

1974 ◽  
Vol 11 (1-6) ◽  
pp. 1-7 ◽  
Author(s):  
D. Watson ◽  
S. Lees ◽  
J. E. H. Stafford
Keyword(s):  
Normal Serum ◽  
Secondary Standard ◽  
Extinction Coefficients ◽  
Serum Thyroxine ◽  
Displacement Analysis ◽  
Molar Extinction Coefficients

Serum thyroxine was assayed concurrently by at least two of three different radio-displacement analysis kits—‘Tetralute’ (Ames), ‘Tetrasorb’ (Abbott) and ‘Thyopac-4’ (Radiochemical Centre). Repeated and careful cross checking by each of the methods was carried out on the ‘standard’ sera supplied with the kits and on other commercially available control sera. Differences of −3 to + 32% in apparent T-4 concentration were found. An unacceptable variability in T-4 content amongst batches of the same control sera was also evident which can be explained only by a lack of constancy in the commercial serum T-4 ‘standards’. The molar extinction coefficients, water and tri-iodothyronine contents of commercial ‘pure’ thyroxine preparations indicate purities of 89–99 %. An examination of published ‘euthyroid’ ranges and those found by the ‘kit’ radiometric methods suggests that many normal serum T-4 values are based on the use of an impure primary or doubtful secondary standard. A primary standardisation of the assay with thyroxine of known purity and of known concentration, as determined from its molar extinction at 324 nm is advocated. Using this procedure, the normal euthyroid range for serum T-4 is 55–148 nmol T4/1 (2.8–7.5 μg T-4I/100 ml) or close to it—in agreement with the earlier findings of Howarth and Maclagan (1969) and Ekins et al. (1969). During the period studied, ‘Tetralute’ produced the most accurate results.

scholarly journals Dysgeusia Due to Zinc Deficiency After Pancreaticoduodenectomy Requiring Continuous Intravenous Zinc Supplementation: a Case Report and Literature Review

2021 ◽  
Author(s):  
Hironobu Hata ◽  
Yojiro Ota ◽  
Katsuhiko Uesaka ◽  
Yutaka Yamazaki ◽  
Tsubasa Murata ◽  
...  
Keyword(s):  
Zinc Deficiency ◽  
Oral Surgery ◽  
Oral Care ◽  
Serum Zinc ◽  
Zinc Level ◽  
Normal Serum ◽  
Acrodermatitis Enteropathica ◽  
Proximal Jejunum ◽  
Zinc Levels ◽  
Serum Zinc Levels

Abstract Background: Zinc is mainly absorbed in the duodenum and proximal jejunum, which are removed during pancreaticoduodenectomy (PD). Little is known about the adverse oral events and skin disorders caused by zinc deficiency after PD. Herein, we reviewed studies regarding the development of zinc deficiency after PD and presented the case of a patient with zinc deficiency after PD, who required home intravenous zinc replacement.Case presentation: A 73-year-old woman with glossitis, taste disorder, and acrodermatitis enteropathica-like eruption on her fingers presented to the Division of Dentistry and Oral Surgery 69 days after PD. Her serum zinc level markedly decreased to 30 μg/dL. Oral zinc administration was inadequate to treat hypozincemia after PD; therefore, multi-trace elements were injected intravenously under readmission. Her serum zinc levels recovered, and the lesions gradually improved. Furthermore, a central venous port was implanted to maintain normal serum zinc levels, and she continued self-injecting zinc at home.Conclusion: Zinc deficiency after PD rarely occurs. The clinical oncologist community, including dentists responsible for the oral care of cancer patients, should be aware of dysgeusia associated with zinc deficiency after cancer surgery, as well as that induced by chemotherapy or head and neck radiation therapy.

Effect of propylthiouracil dose on serum thyroxine, growth, and weaning in young rats

1985 ◽  
Vol 248 (5) ◽  
pp. R524-R530 ◽  
Author(s):  
H. H. Blake ◽  
S. J. Henning
Keyword(s):  
Drinking Water ◽  
Antithyroid Drug ◽  
Developmental Studies ◽  
Potent Inducer ◽  
Serum Thyroxine ◽  
Young Rats ◽  
Infant Rats ◽  
Serum T4

The antithyroid drug propylthiouracil (PTU) is a potent inducer of hypothyroidism in the rat. To evaluate the effects of PTU on serum thyroxine (T4) concentration, growth, and weaning progression during development, five doses of PTU (0.0001, 0.0005, 0.001, 0.005, and 0.01 g/100 ml) were administered to infant rats via drinking water of the dam. The highest dose, 0.01%, is commonly used in developmental studies. The results indicate that 0.001% PTU creates hypothyroid pups without the debilitating characteristics of pups raised on 0.01% PTU. A second experiment examined the effects of 0.001% PTU on serum T4 concentration, growth, and weaning progression during the fourth postnatal week. Serum T4 concentration was depressed throughout the study period to 25% of controls. The hypothyroid pups continued to grow, although they were significantly smaller than untreated controls. Weaning was initiated by postnatal day 22 and completed on day 29. For normal untreated pups, weaning is initiated by day 17 and completed by day 26. Thus hypothyroidism delays but does not abolish the weaning process.

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