TRIIODOTHYRONINE—Clinical Effects in Patients with Suboptimal Response to Other Thyroid Preparations

Thirty patients with evidence of hypometabolism or a clinically related condition were given triiodothyronine after suboptimal response to thyroxin or desiccated thyroid. DL- and L-isomers of triiodothyronine were used and compared. Thirteen patients (43.3 per cent) were improved and 17 (56.6 per cent) were unimproved or became worse. Side effects occurred in 9 of 34 trials (26 per cent), and could not always be eliminated by decreasing the dosage. The highest percentage of good response occurred in a small group (four of five) who received a combination of desiccated thyroid or thyroxin with supplemental triiodothyronine. Despite careful analysis of the data, no basis was found on which to predict which patients would receive benefit from the triiodothyronine. However, the occasional improvement, sometimes dramatic, suggested that a therapeutic trial with triiodothyronine in difficult or unresponsive cases of hypometabolism or hypothyroidism is justified.     

MEASUREMENT OF THYROXIN SYNTHESIS WITH I131—A Test for Evaluation of Thyroid Function in Equivocal States

As the function of the thyroid gland is the synthesis and secretion of thyroxin, a test which correctly measures this process is best for diagnosis of thyroid disorder and for determining the success of therapy. The rate of secretion can be measured with a Geiger counter which indicates what proportion of radioactive iodine in a serum specimen is in the form of thyroxin. The normal proportion is 2 to 10 per cent; in hyperthyroidism the proportion is 50 to 70 per cent, and in hypothyroidism less than 1 per cent.The same test has served to detect metastases of thyroid carcinoma following total thyroidectomy.     

Measurement of thyroxin synthesis with I131; a test for evaluation of thyroid function in equivocal states

As the function of the thyroid gland is the synthesis and secretion of thyroxin, a test which correctly measures this process is best for diagnosis of thyroid disorder and for determining the success of therapy. The rate of secretion can be measured with a Geiger counter which indicates what proportion of radioactive iodine in a serum specimen is in the form of thyroxin. The normal proportion is 2 to 10 per cent; in hyperthyroidism the proportion is 50 to 70 per cent, and in hypothyroidism less than 1 per cent. The same test has served to detect metastases of thyroid carcinoma following total thyroidectomy.     

Hormones and metabolites of arctic foxes (Alopex lagopus) in response to season, starvation and re-feeding

Svalbard's arctic foxes experience large seasonal variations in light, temperature and food supply throughout the year, which may result in periods of starvation. The aim of this work is to investigate if there are seasonal variations in post-absorptive plasma thyroid hormones (free thyroxin (fT(4)), free triiodothyronine (fT(3)) and reverse triiodothyronine (rT(3))) and metabolites (free fatty-acids (FFA) and beta-hydroxybutyrate (beta-OHB)) with season and their response to starvation and re-feeding. The concentrations of post-absorptive free triiodothyronine were significantly higher in November than May, while those of thyroxin, reverse triiodothyronine, free fatty-acids and beta-hydroxybutyrate remained unchanged. Possible explanations for the seasonal variations in free triiodothyronine are discussed. There were no significant changes from post-absorptive concentrations of thyroxin and reverse triiodothyronine in starved and re-fed foxes. However, free triiodothyronine concentrations decreased during starvation and increased again with re-feeding both in May and November. Starvation induced high levels of free fatty acids in both May and November, indicating increased lipolysis. There was a significant increase in beta-hydroxybutyrate in November only, indicating that arctic foxes are capable of protein conservation during starvation.     

Severe euthyroid cardiac disease; technique for treatment with radioiodine

It is possible to safely lower the basal metabolism of patients suffering from severe cardiac disease by administering multiple small doses of radioiodine in order to achieve symptomatic relief. From the present study, multiple small doses of I(131) appeared to be as effective as single or multiple large doses of this material and complications such as thyroiditis, temporary thyrotoxicosis and bone marrow depression were almost always avoided. No damage to the parathyroid glands or the recurrent laryngeal nerve was observed. No radiation sickness developed after therapy.A scintigram of the thyroid gland was useful in determining the size, shape and function of the thyroid gland before and during radioiodine treatment and helped to determine the need for additional treatment. In order to prevent the distressing symptoms of the myxedema state, desiccated thyroid was administered when necessary. In the series of 278 euthyroid patients with severe cardiac disease who were treated with radioactive iodine, results were excellent in 35 per cent of cases and good in 44 per cent. In 21 per cent there was no improvement.     

SEVERE EUTHYROID CARDIAC DISEASE—Technique for Treatment with Radioiodine

It is possible to safely lower the basal metabolism of patients suffering from severe cardiac disease by administering multiple small doses of radioiodine in order to achieve symptomatic relief.From the present study, multiple small doses of I¹³¹ appeared to be as effective as single or multiple large doses of this material and complications such as thyroiditis, temporary thyrotoxicosis and bone marrow depression were almost always avoided. No damage to the parathyroid glands or the recurrent laryngeal nerve was observed. No radiation sickness developed after therapy.A scintigram of the thyroid gland was useful in determining the size, shape and function of the thyroid gland before and during radioiodine treatment and helped to determine the need for additional treatment. In order to prevent the distressing symptoms of the myxedema state, desiccated thyroid was administered when necessary.In the series of 278 euthyroid patients with severe cardiac disease who were treated with radioactive iodine, results were excellent in 35 per cent of cases and good in 44 per cent. In 21 per cent there was no improvement.     

The effect of microwave irradiation on the status of the thyroid gland

Multiple irradiation of rats with microwaves of continuous generation (2450 MHz, 1 mW/cm2) increased and of pulsed generation (3000 MHz, 0.1 to 2.5 mW/cm2) decreased the functional activity of the thyroid gland with no changes in the triiodothyronine and thyroxin in blood serum. The role of the thyroid gland in inducing behaviour effects of microwaves was demonstrated by the method of extirpation.     

Treatment of hypothyroidism with L-thyroxin]

To compare an efficacy of the galenic form of desiccated thyroid gland--Thyreoideum "Polfa" with the synthetic L-thyroxine (Eltroxin Glaxo) in the treatment of hypothyroidism 15 patients were investigated. In all 15 cases before and after treatment ECG and the serum concentrations of cholesterol, thyroxine (T4), triiodothyronine (T3) as well as thyrotropin (TSH) in response to TRH were performed. After the treatment with Thyreoideum "Polfa" in doses 0.2 to 0.6 mg/daily there were neither clinical improvement, normalization of ECG, the serum concentrations of cholesterol, T3, T4 nor TSH. However, after the L-thyroxine treatment (Eltroxin Glaxo) in doses 100 to 200 micrograms/daily the clinical signs of hypothyroidism disappeared in all 15 patients. In ECG the statistically significant increase in voltage of the R and T waves after L-thyroxine treatment were observed. Also a significant decrease in the serum concentration of cholesterol and an increase in T4 and T3 were found. The serum concentration of TSH in response to TRH after the L-thyroxine treatment significantly decreased. L-thyroxine appeared to be a very efficacious in the treatment either primary or secondary hypothyroidism.     

A sensitive immunoradiometric assay for serum thyroid stimulating hormone: a replacement for the thyrotrophin releasing hormone test?

The value as a thyroid function test of a new, rapid, and highly sensitive immunoradiometric assay for thyroid stimulating hormone (TSH) was assessed in 188 consecutive new patients with suspected hyperthyroidism. The diagnosis was made on clinical grounds and on the basis of serum total triiodothyronine and thyroxine concentrations and the response of TSH to thyrotrophin releasing hormone (TRH) as measured by radioimmunoassay. In all except one patient the basal TSH concentration by immunoradiometric assay predicted the response of TSH by radioimmunoassay to TRH, an undetectable value being recorded in patients with a subnormal response and a measurable value in those with a normal test result. This clear relation was not observed for basal TSH concentrations as measured by radioimmunoassay. In a series of 39 hospital inpatients with acute or chronic non-thyroidal illness, of whom 11 had low concentrations of total thyroxine or triiodothyronine, or both, basal TSH concentrations were detectable by both radioimmunoassay and immunoradiometric assay in all cases and were associated with normal responses to TRH. The immunoradiometric assay for TSH, which is commercially available, may therefore obviate the need for the more time consuming TRH test and simplify the approach to thyroid function testing in patients with suspected hyperthyroidism.     

Effect of Zinc and Iron Fortification of the Feed on Liver and Thyroid Function in Rats

Changes in plasma glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), triiodothyronine (T3), and thyroxin (T4) of male rats, following 8?weeks of administration of different concentrations of elemental iron (EI), sodium iron ethylenediaminetetraacetate (NaFeEDTA), zinc sulfate (ZnSO(4)), and zinc oxide (ZnO) in whole wheat flour were investigated. Liver enzymes and thyroid hormones were determined using colorimetric methods and enzyme immune assay, respectively. Ingestion of fortified diets by the male rats did not show a marked effect on GOT and GPT, the exception being NaFeEDTA fed alone and EI with ZnO-fortified diets indicating a significant (p?相似文献   

Effect of immunization on functional state of thyroid gland and thyroxine binding in rat organs

A number of modern research methods were used in experiments on 220 white rats to examine thyroid function at varying times after single immunization with typhoid vaccine. It was found that on the 1st and 2nd days of the observation period, only cAMP level of the thyroid parenchyma decreases. Three, four and seven days following immunization, thyroid function is drastically reduced, which manifests by a decrease in 131I uptake by the thyroid gland. Also decreased were the conversion ratio, the levels of thyroxine and triiodothyronine in blood serum and incorporation of labeled thyroxin by the heart, liver and spleen. During the productive phase of the immunogenesis (days 10, 15, 20 and 25), all the test indicators considerably increase. The phases of the reaction obtained seem likely to be a consequence of reciprocal relationship between the thyroid and sympathoadrenal systems (the inductive period), as well as by the feedback effect (the productive period of antibody formation). The reaction of thyroid function to immunization is regarded as a component of non-specific adaptation response of the body to an extreme irritant, that provides for metabolic reconstruction necessary for the synthesis of antibodies and formation of immune lymphocyte populations.     

Determination of thyroxine and triiodothyronine in the thyroid glands of encephalectomized rat fetuses

Concentration of thyroxin and triiodothyronine in the thyroid gland of encephalectomized and intact fetuses of rats with normal and prolonged gestation period was determined by means of isotope methods. Encephalectomy of 19-day old fetuses did not produce any significant effect on the concentration of thyroid hormones in the gland 2 and 4 days after the operation. The results obtained pointed to the absence of the hypothalamic control over the thyroid function in prenatal development of rats.     

The effects of desiccation and rehydration on the lone star tick

This study describes the effects of desiccation and rehydration on the water content, haemolymph volume (per cent), osmolarity, and concentrations of Na, K, Mg, and Ca in the haemolymph of the lone star tick, Amblyomma americanum.The water content percentages of ‘severely desiccated’, ‘moderately’ and ‘fully hydrated’ ticks were 46·0, 52·8, and 60·3 per cent respectively. The lowest and highest of these were near the minimum and maximum possible.The haemolymph volume (per cent) of ‘severely desiccated’ ticks was regulated near the level of ‘moderately hydrated’ ticks despite significant decreases in total body water content and increases in osmolarity and concentration of sodium. Conversely, the change from ‘severely desiccated’ to ‘moderately hydrated’ ticks can be viewed as causing an increase in total body water, decrease in blood osmolarity and sodium, but little change in haemolymph volume (per cent).Most of the water taken up by ‘moderately hydrated’ ticks (while becoming ‘fully hydrated’) was added to the haemolymph. At the same time, there was little change in the blood osmolarity or haemolymph concentration of sodium. Conversely, the change of ‘fully’ to ‘moderately hydrated’ ticks was marked by a substantial loss of haemolymph volume (per cent) but little change in osmolarity and concentration of sodium.The concentration of potassium was regulated over the full range of desiccating and hydrating conditions. The lone star tick appeared less able to regulate its haemolymph concentrations of Ca and Mg; both fluctuated at the same rate, but inversely as the haemolymph volume (per cent).It appears that a carefully controlled movement of solutes (Na the predominant cation) between haemolymph and non-haemolymph tissue is intimately linked with haemolymph volume regulation and movement of water into the haemolymph during hydration.     

Effects of dietary caloric restriction and aging on thyroid hormones of rhesus monkeys.

Plasma levels of thyroid hormones - triiodothyronine (T 3 ), thyroxin (T 4 ), and thyroid-stimulating hormone (TSH) were measured in male and female rhesus monkeys (Macaca mulatta) fed either ad libitum or a 30 % calorie-restricted (CR) diet (males for 11 years; females for 6 years). The same hormones were measured in another group of young male rhesus monkeys during adaptation to the 30 % CR regimen. Both long- and shorter-term CR diet lowered total T 3 in plasma of the monkeys. The effect appeared to be greater in younger monkeys than in older counterparts. No effects of CR diet were detected for either free or total T 4, although unlike T 3, levels of this hormone decreased with age. TSH levels also decreased with age, and were increased by long-term CR diet in older monkeys only. No consistent effects of shorter-term CR diet were observed for TSH. In the light of the effects of the thyroid axis on overall metabolism, these results suggest a possible mechanism by which CR diets may elicit their well-known beneficial 'anti-aging' effects in mammals.     

Insulin versus oral agents in the management of Cystic Fibrosis Related Diabetes: a case based study

Background

Although thyroxin therapy clearly is beneficial to children with frank hypothyroidism there is little data on the effects of thyroxin in children with compensated or subclinical hypothyroidism. The objective of this study was to determine the effect of thyroxin therapy on cognitive function in children with compensated hypothyroidism. The hypothesis was that thyroxin therapy would change neuropsychological function.

Methods

Eleven patients with a history of sub clinical hypothyroidism entered the study. At the start of the study, six out of the 11 were on thyroxin therapy, while 5 were off therapy. All patients underwent a battery of neuropsychological testing and thyroid function tests at the start of study. Based on the results of thyroid function tests, two of the 5 patients who were off thyroxin were started back on thyroxin. All of the 6 patients who were on thyroxin were taken off thyroxin. All patients then underwent repeat neuropsychological testing and thyroid functions after an average of 91 days.

Results

Thyroxin therapy could not be shown to have an effect on neuropsychological function in this short term study. Our patients had attention problems as compared to the normal population. No significant differences were found between our subjects and normal population standards in verbal processing, visual processing, motor speed/coordination and achievement.

Conclusion

In this small, short term study, thyroxin therapy could not be shown to affect neuropsychological function in children with compensated hypothyroidism. These children may have attention problems but appear to have normal verbal and visual processing, motor speed/coordination and achievement.     

Thyroid hormone levels in the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex.

Hypothalamic-pituitary dysfunction and thyroid gland cytomegalovirus inclusions have been described in patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC). We evaluated 80 patients with AIDS or ARC for the frequency of hypothalamic-pituitary or thyroid gland failure and altered serum thyroid hormone levels due to nonthyroidal disorders. One patient had subclinical hypothyroidism. Of these patients, 60% had low free triiodothyronine (T3) index values and 4% had low free thyroxine (T4) indexes; none of the latter had hypothalamic-pituitary or thyroid gland failure, since all serum cortisol values were greater than or equal to 552 nmol per liter (greater than or equal to 20 micrograms per dl) and all thyrotropin levels were less than or equal to 3 mU per liter (less than or equal to 3 microU per ml), respectively. Those who died had lower total T4 and T3, free T3 index, and albumin levels than those discharged from hospital. Serum total T4 and T3 levels correlated with albumin levels and total T3 with serum sodium levels. Serum total T3 levels best predicted the outcome of the hospital stay (accuracy = 82%). Thus, abnormal serum thyroid hormone levels in AIDS or ARC patients are most frequently due to nonthyroidal disorders, but hypothalamic-pituitary or thyroid gland failure may occur.     

Thyroid hypofunction in Down’s syndrome

Oxidative stress affecting the thyroxin biosynthesis might explain the proneness of patients with Down's syndrome (DS) (trisomia 21) to develop hypothyroidism. Thyroideal cells are exposed to endogenous H2O2 that acts as a cofactor for the iodination of thyroxin precursors. The gland has high levels of selenium-containing proteins, including peroxide-detoxicating enzyme proteins. The object of the present study was to explore the hypothesis of a role of an imbalance between toxic oxygen production and protective metalloenzymes during the development of thyroid hypofunction in DS patients. We analyzed serum levels of thyroid hormones and trace metals in 38 institutionalized adults with DS, using mentally retarded subjects matched for age, sex, and behavioral function as controls. The DS patients had significantly lower mean values of free thyroxin (fT4) and increased TSH (thyroid stimulating hormone), as compared to the controls. They had lower serum selenium than the controls. A positive correlation was observed between serum concentrations of fT4 and selenium in the DS patients (r = 0.393, p < 0.05). No significant differences were found between the fT4 or the TSH concentrations in the patients with and without circulating antithyroid autoantibodies. Our results support the suggestion that thyroid hypofunction in patients with Down's syndrome in some way is linked to the low serum levels of selenium found in these patients. It is suggested that selenium-containing proteins are involved in thyroid hormonal synthesis, by protecting biosynthetic processes against the toxicity of free oxygen radicals.     

No Longterm Severe Thyroid Dysfunction Seen In Patients With Preexisting Reduced Serum Tt3 Concentrations After A Single Large Dose Of Iodinated Contrast

Objective: After an intravenous bolus injection of 100 mL of iodinated contrast agent (370 mgI/mL), the amount of iodine atoms entering the blood is tens of thousands of times the daily dose of iodine recommended by the World Health Organization. However, the effect of iodinated contrast in patients with nonthyroidal illness, manifested as reduced serum total triiodothyronine (TT3) concentrations, is unclear. We studied the effect of iodinated contrast on thyroid function and auto-antibodies in patients with reduced TT3 after diagnosis and treatment of coronary heart disease.Methods: This was a prospective cohort study. One hundred and fifty-four stable angina pectoris patients with reduced TT3 and normal thyroid-stimulating hormone (TSH), free thyroxine (FT4), and reverse triiodothyronine (rT3) were enrolled from January, 2017, to June, 2018. All subjects had no history of thyroid dysfunction and had no recent infections, tumors, trauma, or other critical illnesses. Fourty-one patients underwent coronary angiography and 113 patients underwent coronary intervention.Results: There were 6 patients (3.9%) with hypothyroidism and 30 patients (19.5%) developed subclinical hypothyroidism (SCHypo) on the first day after surgery. There were 6 patients (3.9%) with hypothyroidism, 6 patients (3.9%) with SCHypo, and 18 patients (11.7%) with subclinical hyperthyroidism (SCHyper) at the first month postsurgery. There were 23 patients (14.9%) with SCHyper and 6 patients (3.9%) with SCHypo at the sixth month after surgery. No patient with longterm severe thyroid dysfunction occurred during follow-up. The levels of free triiodothyronine, FT4, TT3, total thyroxine, and TSH showed statistically significant changes at 1 day, and 1, 3, and 6 months postoperative (P<.005). The level of rT3 showed no statistically significant change at 1, 3, and 6 months postoperative (P>.05). The levels of thyroglobulin antibody and thyroid peroxidase antibody decreased at 6 months postoperative (P<.001).Conclusion: The risk of subclinical thyroid dysfunction and transient hypothyroidism occurred with a single large dose of iodinated contrast in the diagnosis and treatment of coronary heart disease, but no longterm severe thyroid dysfunction occurred. Patients with preoperative thyroid antibody elevation were more likely to have subclinical thyroid dysfunction after surgery.Abbreviations: FT3 = free triiodothyronine; FT4 = free thyroxine; PCI = percutaneous coronary intervention; rT3 = reverse triiodothyronine; SCHyper = subclinical hyperthyroidism; SCHypo = subclinical hypothyroidism; TGAB = thyroglobulin antibody; TPOAB = thyroid peroxidase antibody; TT3 = total triiodothyronine; TT4 = total thyroxine; TSH = thyroid-stimulating hormone; WHO = World Health Organization     

Desiccation of Pinus foliage induced by conifer sawfly oviposition: effect on egg viability

Abstract 1. Desiccation of needles following oviposition by Neodiprion lecontei in Pinus resinosa caused high egg mortality. Eight-five per cent of pine needles into which sawflies oviposited subsequently desiccated, compared with 2.5% of needles without eggs. No larval emergence occurred from desiccated needles.
2. Within affected shoots, the probability of desiccation increased with the extent of oviposition. In paired comparisons of needles, 41.2% of needle length was occupied by eggs in desiccated needles, compared with 24.0% of needles without desiccation.
3. Both density-dependent and density-independent factors may contribute to desiccation of egg-laden needles. The likelihood that needle vasculature will be severed by ovipositing females probably increases with population density. Drought, which was high during the observations, probably increases the incidence of needle desiccation following mechanical injury caused by oviposition.     

Induction of Ca2+ ion transport in human thrombocytes as affected by thyroid hormone receptors from malignant transformed cells

The effect of thyroid hormone receptors isolated from normal and malignant cells on the induction of Ca2+ transport to platelets was studied. It is established that the receptor isolated from malignant cells by thyroxin (T4) or triiodothyronine (T3) stimulates (three-fold) the induction of Ca2+ transport to platelets. The effect is blocked by verapamil, which is the inhibitor of Ca2+ channels in plasma membranes. It is shown that neither the receptor of cancer cells, nor hormones (T3 or T4) influence the transport of Ca2+ to platelets without preliminary complexing. The hormone-receptor complex failed to affect the concentration of "cytoplasmic" Ca2+ in platelets analogous experimental conditions. It is suggested that the increased Ca2+ content in cancer cells can be partially attributed to the ability of thyroid hormone receptor of cancer cells to induce Ca2+ transport across the plasma membrane.