Free T4 Concentrations Research Articles

Electrocardiography in euthyroid individuals: a Danish general population study

Thyroid hormones within the euthyroid range have been linked to mortality and differences in heart rate. However, some relations between thyroid hormone concentration and various electrocardiographic measurements remain unassessed. We aimed to investigate the association between thyroid hormone concentrations within the euthyroid range and different electrocardiographic markers in people free of thyroid disease. We obtained electrocardiograms (ECG) and blood samples of free T4, total T3, and thyrotropin (TSH) in 20,852 subjects from the general population (the GESUS study). Relations between concentrations of TSH, free T4, and total T3 and heart rate, QTc, QRS duration, PR interval, P-wave duration and T-wave morphology were assessed in a multivariate adjusted linear model stratified by sex. Roughly half of the 18,046 included participants with thyroid hormone measurements within euthyroid range were men, and the average age was 56 years. Heart rate increased with concentrations of T3 (6.4 bpm/nM, P<0.001 in women and 5.3 bpm/nM, P<0.001 in men) and T4 (3.7 bpm/10pM, P<0.001 in women and 3.1 bpm/10pM, P<0.001 in men). We found no relation between TSH and heart rate. PR interval and QRS duration decreased with higher concentrations of T3 (all P<0.01). QTc increased with higher concentrations of T4 in men (5 ms/10pM), and T waves were flatter, more asymmetric, and more often had notches with higher concentrations of T4 (all P≤0.01). Thyroid hormone concentrations within the euthyroid range in people free of thyroid disease were associated with changes in the electrocardiogram in a general population.

Subclinical thyroid dysfunction in the first trimester of pregnancy: 'Disease' versus physiological (pulsatile) variation in TSH concentrations.

There is no universal consensus regarding cut-off points for TSH in pregnancy, so concentrations of 2.5 or 4.0mIU/L were suggested for first trimester (Endocrine Society [2012] and ATA [2017] guidelines, respectively). Yet, the impact of physiological variation in TSH secretion has not been assessed. We assessed baseline concentrations of free T4, free T3 and TSH at 30-minute intervals (between 7.00 and 9.00hours) in 110 healthy pregnant women, age 30.2±6.0years, 9.9±2.4weeks of gestation, and in 19 female controls, age 28.9±10.7. Mean TSH concentrations in pregnant women were 1.62±1.26 mIU/L and on average varied by 39.5% (dispersion between the highest and the lowest TSH), with no difference in TSH variation between pregnant women and controls. Taking into account the highest TSH out of five consecutive measurements, TSH >2.5mIU/L and TSH above 4.0mIU/L were found in 23 (20.9%) and 10 (9.1%) pregnant women, respectively. In contrast, when the lowest TSH value was considered, then concentrations of TSH >2.5mIU/L and >4.0mIU/L were found in 14 (12.7%) and 4 (3.6%) women, respectively. This discrepancy was even more pronounced in aTPO-negative subjects (21 [21.2%] vs 8 [8.1%] women, for TSH >2.5mIU/L, and six [6.06%] vs one [1.01%], for TSH >4.0 mIU/L). Furthermore, either six (5.4%) or 10 (9.1%) women had TSH concentrations below 0.1mIU/L. In a significant number of patients, diagnosis of subclinical thyroid dysfunction could be erroneously made not as a result of 'disease', but as a result of physiological variation in TSH concentrations.

Subclinical hypothyroidism in childhood, treatment or only follow-up?

BackgroundSubclinical hypothyroidism (SH) is defined as serum levels of thyroid-stimulating hormone (TSH) above the upper limit with normal concentrations of free T4 (fT4). Its management remains challenging. The aim of the study was to evaluate clinical and laboratory findings as well as the clinical course of children with SH followed in a third level hospital. Sixty-five patients aged between 2 and 18 years old were retrospectively studied.MethodsThe patients were followed for a median period of 9 months (range 6 months to 24 months). Those who normalized TSH levels were discharged (Group 1). If TSH persisted mildly elevated (5-10μUI/mL) with normal fT4 and negative TPOAb/TgAb, they were classified as Group 2 and followed semi-annually without treatment. Those patients whose TSH raised ≥10μUI/mL or who maintained TSH 5-10μUI/mL and positive TPOAb/TgAb were considered suitable for thyroxin therapy (Group 3, G3).ResultsIn 89% of our patients, TSH concentrations spontaneously reverted to normality or remained stable without treatment (Groups 1 and 2), whereas less than 11% progressed to clinical hypothyroidism (Group 3). Baseline TSH was significantly lower in group 1 than in group 3. In group 3 the prevalence of female sex (71%) was higher and TPO antibodies were present in 85% of patients. The risk of developing overt hypothyroidism in patients with positive anti-thyroid antibodies respect to those who normalized TSH was 45 (95%CI 6.5–312.5).ConclusionBaseline TSH, female sex and the presence of thyroid autoimmunity were the best predictors of the evolution to SH over time.

MON-081 Mathematical Modeling of Residual Endogenous FT4 Synthesis and Exogenous L-Thyroxine Administration over the First 2 Years of Life in Infants with Congenital Hypothyroidism

L-Thyroxine (L-T4) is the treatment of choice of congenital hypothyroidism (CH). Longitudinal measurements of free T4 (FT4) serum concentrations were collected over the first two years of life with oral L-T4 treatment in infants with CH. Purpose of this study was to develop an integrated mathematical model to characterize the kinetics of exogenous L-Thyroxine (L-T4) after multiple dosing in infants with CH, and the dynamics of residual endogenous FT4 synthesis under treatment in the context of severe, moderate and mild disease.A total of 200 FT4 concentrations from 30 patients were available for analysis. At start of treatment, mean (standard deviation [SD]) postnatal age and weight of the population were 11 (8) days and 3.9 (1.3) kg. Mean (SD) pretreatment FT4 concentration was 11.3 (7.4) pmol/L. Measured FT4 concentrations were modelled as sum of residual endogenous FT4 and exogenously administered FT4 (L-T4). The integrated mathematical model consists of an absorption compartment for the exogenous FT4 administration, and a central compartment for measured FT4 with linear elimination. Hence, for residual endogenous and exogenous FT4 the same elimination rate constant was assumed. For the residual endogenous synthesis, different approaches were tested: a constant production and typical time-dependent production functions. FT4 data were analyzed using nonlinear mixed-effects modeling.The integrated mathematical model with a time-dependent non-linear Emax function describing a decreasing residual endogenous FT4 synthesis for increasing time provided the best data fit in terms of Akaike value and various goodness-of-fit plots. This is in line with the expected progressive suppression of the thyroid stimulating hormone by the exogenous FT4, and the subsequent decrease of residual FT4 endogenous synthesis. The developed mathematical model allows simulation of FT4 pharmacokinetic profiles for different disease severities and different dosing regimens.

SAT-LB86 Improvement In Metabolic Indices Including Thyroid HormonesVia Enhanced Absorption Of Nutrients By Teduglutide In Short Bowel Syndrome

Background: Short bowel syndrome is characterized by maldigestion and malabsrption resulting in deficiencies of multiple nutrients including vitamins and minerals. Most subjects required parental elimination for survival. GLP 2 RA Teduglutide was recently approved for treatment of short-bowel syndrome especially for those requiring parenteral support. Objective: To demonstrate the utility of GLP2 Receptor Agonist Teduglutide in improvising multiple metabolic indices In presence of short bowel syndrome. Case presentation: 66-year-old Caucasian female presented with a history of short bowel syndrome and associated vitamin deficiencies, hypothyroidism requiring large dose of levothyroxine, diarrhea, and liver cirrhosis. Upon starting teduglutide the subject saw improvement in her symptoms. Moreover, daily dose of levothyroxine required reductions from 300 mcg to 150 mcg to maintain desirable serum concentrations of free T4, free T3 and TSH. Finally, serum levels of several vitamins attained greater than therapeutic concentrations requiring dosage reductions. Also notable was the improvement in her liver function tests, remission from ascites and regeneration of liver nodules. Conclusion: Herein, we report an adult subject with short bowel syndrome with concurrent hypothyroidism and multiple vitamin deficiencies who following administration of GLP2 RA therapy demonstrated a marked improvement in her metabolic parameters with some requiring reduction in daily dose along with improvement in manifestations of liver cirrhosis.

Abdominal Obesity Phenotypes and Incidence of Thyroid Autoimmunity: A 9-Year Follow-up

ABSTRACT Purpose The association between obesity and autoimmune diseases has been suggested by several previous studies. The objective of our study was to assess the association of abdominal obesity phenotypes with thyroid autoimmunity. Materials and methods This study was conducted within the framework of a population-based cohort study, Tehran Thyroid Study (TTS) on 4708 subjects without thyroid autoimmunity at baseline. Participants were categorized into four abdominal obesity phenotypes according to waist circumference (WC) and other metabolic syndrome components. Serum concentrations of thyroid peroxidase antibody (TPOAb), free T4 (FT4), thyrotropin (TSH), glucose, and lipid profiles were measured after 3, 6 and 9 years of follow-up. Cox proportional hazard models were used to evaluate associations of different phenotypes with the incidence of thyroid autoimmunity, adjusted for age, sex, FT4, and TSH. Results Highest and lowest incidence rates of TPOAb positivity were observed among metabolically unhealthy, non-abdominally obese (MUNAO) [8.78 (7.31–10.55) per 1000 person-years of follow-up] and metabolically unhealthy abdominally obese (MUAO) [4.98 (3.88–6.41) per 1000 person-years of follow-up] phenotypes. Considering the metabolically healthy non-abdominal obese (MHNAO) individuals as reference, none of metabolically healthy abdominally obese (MHAO), MUNAO, and MUAO phenotypes were associated with increased risk of developing TPOAb positivity. Compared to individuals with high WC, the incidence rate (95%CI) of TPOAb positivity was higher among those with normal WC: 8.44 (7.13–10.0) vs 5.11 (4.01–6.51) per 1000 person-years, respectively. Higher WC was not associated with incident TPOAb positivity. Conclusion There was no significant association between baseline abdominal obesity phenotype status and development of TPOAb positivity over 9 years of follow-up.

A Case of Familial Nonautoimmune Hyperthyroidism During Pregnancy

Familial nonautoimmune hyperthyroidism (FNAH) is a rare disease. To date there are few, if any, reports of pregnancies in women with FNAH. Our objective here is to present such a case. Free thyroxine (free T4), free triiodothyronine (free T3), thyroid-stimulating hormone (TSH), and antibodies related to the thyroid were measured. Fetal thyroid function indicators including thyroid volume and ossification were checked using ultrasound. Thyroid-stimulating hormone receptor (TSHR) gene analyses were performed. The patient was a 30-year-old woman with no past medical history. She was introduced to our hospital in the fifth gestational week for pregnancy care because her family history revealed that her mother had nonautoimmune hyperthyroidism with a TSHR-activating germ-line mutation (Asn406Ser). The serum free T4 was 1.88 ng/dL (normal, 0.62 to 1.19 ng/dL), free T3 was 3.27 pg/mL (normal, 2.55 to 3.88 pg/mL), TSH was 0.02 μIU/mL (normal, 0.007 to 3.619 μIU/mL), and TSHR was negative which were considered to be consistent with mild primary hyperthyroidism. Serum free T4, free T3, and TSH concentrations were monitored every 4 to 6 weeks with a peak free T4 of 2.23 ng/dL noted at gestational week 9. The patient had no signs related to hyperthyroidism throughout pregnancy. The patient delivered a 3,518 g girl at 40 weeks of gestation. Genetic analysis of her TSHR gene showed heterozygous Asn406Ser mutation. The offspring did not show any signs of prenatal hyperthyroidism, and thyroid function at day 6 after delivery revealed a free T4 of 2.41 ng/dL (normal, 1.83 to 2.91 ng/dL) and a TSH of 3.55 μIU/mL (normal, 0.51 to 4.57 μIU/mL). Women with FNAH and mild thyrotoxicosis prior to pregnancy may have continuous hyperthyroidism with additional change due to the series of human chorionic gonadotropin secretion during pregnancy.

Familial dysalbuminemic hyperthyroxinemia confounding management of coexistent autoimmune thyroid disease.

SummaryFamilial dysalbuminemic hyperthyroxinemia (FDH) is a cause of discordant thyroid function tests (TFTs), due to interference in free T4 assays, caused by the mutant albumin. The coexistence of thyroid disease and FDH can further complicate diagnosis and potentially result in inappropriate management. We describe a case of both Hashimoto’s thyroiditis and Graves’ disease occurring on a background of FDH. A 42-year-old lady with longstanding autoimmune hypothyroidism was treated with thyroxine but in varying dosage, because TFTs, showing high Free T4 (FT4) and normal TSH levels, were discordant. Discontinuation of thyroxine led to marked TSH rise but with normal FT4 levels. She then developed Graves’ disease and thyroid ophthalmopathy, with markedly elevated FT4 (62.7 pmol/L), suppressed TSH (<0.03 mU/L) and positive anti-TSH receptor antibody levels. However, propylthiouracil treatment even in low dosage (100 mg daily) resulted in profound hypothyroidism (TSH: 138 mU/L; FT4: 4.8 pmol/L), prompting its discontinuation and recommencement of thyroxine. The presence of discordant thyroid hormone measurements from two different methods suggested analytical interference. Elevated circulating total T4 (TT4), (227 nmol/L; NR: 69–141) but normal thyroxine binding globulin (TBG) (19.2 µg/mL; NR: 14.0–31.0) levels, together with increased binding of patient’s serum to radiolabelled T4, suggested FDH, and ALB sequencing confirmed a causal albumin variant (R218H). This case highlights difficulty ascertaining true thyroid status in patients with autoimmune thyroid disease and coexisting FDH. Early recognition of FDH as a cause for discordant TFTs may improve patient management.Learning points:The typical biochemical features of familial dysalbuminemic hyperthyroxinemia (FDH) are (genuinely) raised total and (spuriously) raised free T4 concentrations due to enhanced binding of the mutant albumin to thyroid hormones, with normal TBG and TSH concentrations.Given the high prevalence of autoimmune thyroid disease, it is not surprising that assay interference from coexisting FDH may lead to discordant thyroid function tests confounding diagnosis and resulting in inappropriate therapy.Discrepant thyroid hormone measurements using two different immunoassay methods should alert to the possibility of laboratory analytical interference. The diagnosis of FDH is suspected if there is a similar abnormal familial pattern of TFTs and increased binding of radiolabelled 125I-T4 to the patient’s serum, and can be confirmed by ALB gene sequencing.When autoimmune thyroid disease coexists with FDH, TSH levels are the most reliable biochemical marker of thyroid status. Measurement of FT4 using equilibrium dialysis or ultrafiltration are more reliable but less readily available.

Glycemic status in patients with primary hypothyroidism and its relation to disease severity

Background: Primary hypothyroidism can be defined as an increase in serum thyroid-stimulating hormone (TSH) level, and the concentration of free T3, free T4, T3, and T4 is low. Hypothyroidism is a prevalent disease mostly affecting middle-aged women. One of the most important determinants of glucose homeostasis is thyroid hormones. Hypothyroid patients have a higher prevalence of insulin resistance and tendency to Type 2 diabetes mellitus than the normal individual. Objective: To investigate the correlation between TSH and hemoglobin A1c (HbA1C) in patients with primary hypothyroidism; so, to study the effects of hypothyroidism on glucose metabolism. Subjects and Methods: Ninety-five Iraqi primary hypothyroidism patients and 40 healthy persons taken as control were selected from Specialized Centre for Endocrinology and Diabetes during the period from June 2017 to January 2018. The patients were diagnosed previously as cases of primary hypothyroidism, and they were on treatment and still on treatment. All patients were sent to investigate TSH, T4, T3, and HbA1c. The patients were subdivided into three main groups: first is uncontrolled nondiabetic primary hypothyroid group (36 patients), second is controlled nondiabetic primary hypothyroid group (43) and third is the diabetic primary hypothyroid group (16 patients). Results: A significant difference (P

The Effects of Zinc Methionine on Reproductive and Thyroid Hormones in Rats with Polycystic Ovarian Syndrome.

Background:Polycystic ovarian syndrome (PCOS) is an endocrine disorder in fertile women, which seems to be adversely affected by associated thyroid dysfunction. Zinc methionine (ZM) has positive effects on PCOS, but its concerted effects on PCOS and thyroid function have not been investigated. We evaluated the effects of ZM on reproductive and thyroid hormones and the number of follicles in rats with PCOS.Materials and Methods:This study was conducted on 45 female rats, using sesame oil as control; PCOS animals administered with 0, 25, 75, and 175 mg/kg BW of ZM. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and thyroid function were investigated. Premature follicles (PMF), primary follicles (PF), preantral follicles (PAF), antral follicles (AF), corpus luteum (CL), and cystic follicles (CF) were assessed.Results:PCOS decreased the concentrations of FSH and free T4, but increased the levels of LH, TSH, and LH/FSH ratio (ALL P < 0.05). ZM at a dose of 75 and 175 mg increased the level of FSH, free T4, and decreased LH, TSH, and LH/FSH ratio (ALL P < 0.05). Induction of PCOS decreased PMF, PF, PAF, AF, and CL, but increased CF (P < 0.05). PCOS treated groups (75 and 175 mg/kg) increased these follicle numbers and decreased CF compared to ZM 25 mg/kg and PCOS groups (Both P < 0.05).Conclusions:Although the induction of PCOS had a negative effect on reproductive and thyroid hormones and follicle numbers, ZM treatment (75 and 175 mg/kg) overcame the negative effects. A high dosage of ZM can alleviate the hormonal and cysts disturbances occurring in PCOS.

Subclinical hyperthyroidism

Subclinical hyperthyroidism (SH) is a relatively common disorder; it is defined as a condition in which the thyroid hormones thyroxine (T4) and triiodothyronine levels (T3) are normal with low or even undetectable thyroid-stimulating hormone (TSH) levels. SH may be caused by exogenous or endogenous factors with TSH suppressive therapy in differentiated thyroid cancer or unintentional over-replacement L-T4 therapy being the most common causes. Frank symptoms of hyperthyroidism is most often absent. Patients often present with goitre or for other symptoms of mild thyroid hormone excess such as headache, reduced feeling of well-being, and inability to concentrate. SH leads to increased risk of cardiovascular morbidity and mortality, it may accelerate the development of osteoporosis, and increase bone vulnerability to trauma, especially in postmenopausal women and elderly. It reduces the quality of life, affecting both the psycho and somatic components of wellbeing. Diagnosis of SH is confirmed by repeated testing of TSH spaced months apart in the presence of normal free T3 and T4 concentrations. Radionuclide uptake scan aids us in the diagnosis of the cause of SH. The treatment of SH is similar to the treatment of overt hyperthyroidism, it should be based on the underlying etiology.

Serum Free T4 Concentration: More Accurate and Reliable than TSH as an Indicator of Thyroid Gland Function

Objective: To compare the accuracy and reliability of Free T4 or TSH determination as the single initial screening test in assessment of thyroid function.

A metabolomic study on the gender-dependent effects of maternal exposure to fenvalerate on neurodevelopment in offspring mice

BackgroundThe general population is widely exposed to fenvalerate. However, the effects of maternal exposure to fenvalerate on neurodevelopment in offspring and the underlying metabolic mechanism are largely unknown. MethodsPregnant mice were exposed to fenvalerate for 11 consecutive days. The forced swimming test (FST) was performed in 35 day-old offspring to investigate the effects of fenvalerate on neurobehavioral responses. Blood serum free T4 and free T3 concentrations were measured using commercial ELISA. Blood and thyroid samples were used for metabolomic analyses with UPLC Q-Exactive. The expression levels of neurotransmitter metaolite receptors were determined in the frontal cortex of offspring using real-time PCR. ResultsThe immobility time, free T4 and free T3, and expression levels of Htr1a and Htr2a were statistically changed in offspring male mice. Metabolomic analysis revealed that the pentose phosphate pathway, starch and sucrose metabolism, glutamic acid metabolism were the key changed pathways in the blood, and thiamine metabolism was the key changed pathway in the thyroid. ConclusionPrenatal exposure to fenvalerate affected neurodevelopment in male offspring mice both via the changed abundances of metabolites involved in glycolysis related metabolism and medium-chain fatty acid metabolism, and the changes in 5-HT receptor expression.

Physician Perception and Patient Input Are Important Influences in the Treatment of Hypothyroidism

Physician Perception and Patient Input Are Important Influences in the Treatment of Hypothyroidism

Short-term biological variation of serum thyroid hormones concentrations in clinically healthy cats

Thyroid disease is common in cats, but little is known about the biologic variability of serum thyroid hormone concentrations and its impact on diagnostic utility in either healthy cats or cats with thyroid disease. The purpose of this study was to determine the biological variation, index of individuality, and reference change values for thyroid hormones and thyroid-stimulating hormone (TSH) in clinically healthy cats. Serum samples for analysis of total thyroxine (T4), triiodothyronine (T3), free T4 by dialysis, and TSH were obtained weekly for 6 wk from 10 healthy cats, then frozen until single-batch analyzed. Data were evaluated for outliers, and we determined the CV within individual cats (CVI) and between individual cats (CVG) for each hormone and the variation between duplicates or analytical variation (CVA). The index of individuality and reference change values for each hormone were then calculated. Serum concentrations of total T4, free T4, T3, and TSH all showed greater variation between cats (CVG) than within cats (CVI). Total and free T4 had an intermediate index of individuality (1.1 and 1.2, respectively), suggesting that these hormones would be best evaluated by a combination of their population-based reference intervals and reference change values. Serum TSH concentrations had high index of individuality (1.8), suggesting this hormone would be best evaluated with reference change values rather than the population-based reference interval. Total T3 also had a high calculated index of individuality (1.8); however, T3 had high ratio of analytical variation (CVA) to within cat variation (CVI), so RCV could not be accurately calculated. This study demonstrates that clinically normal cats show considerable interindividual biological variation in serum thyroid hormone and TSH concentrations, whereas the intraindividual variability in hormone concentrations is much narrower. This suggests that for all serum thyroid hormones, but especially serum TSH and T3 concentrations, comparing individual cat's hormone results to a population-based reference interval may be misleading, especially in those with early or subclinical thyroid disease. Clinicians might improve the diagnosis of feline thyroid disease by establishing baseline concentrations of T4, free T4, T3, and TSH for individual cats (ideally when healthy) and applying reference change values to subsequent measurements.

No association between zinc and thyroid activity in obese women.

Obesity is characterized by changes in the metabolism of zinc and thyroid hormones. Studies have also shown the role of zinc in the function and metabolism of thyroid. The present study aimed to evaluate the relationship between serum concentrations of thyroid hormones, dietary zinc intake and zinc distribution in obese women. A case-control study was conducted enrolling 98 women aged between 20 and 50years old who were divided into case group (BMI≥35kg/m2) and control group (BMI=18.5-24.9kg/m2). Patients underwent anthropometric measurements and analysis of dietary zinc intake, which was performed by a three-day food record. Zinc concentrations in plasma and erythrocytes were determined by inductively coupled plasma optical emission spectrometry. Serum concentrations of thyroid hormones and antibodies were determined by chemiluminescence. Mean values of dietary zinc intake were higher than recommended (10.37±3.12mg/day and 11.37±4.36mg/day for control and obeses, respectively). Obese women had reduced plasma (67.22±5.96μg/dL) and erythrocyte (37.16±3.64μg Zn/gHb) zinc concentrations when compared to the control group (plasma: 89.71±13.33μg/dL; erythrocyte: 42.68±3.73μg Zn/gHb) (p<0.001). Serum TSH (control: 2.62±1.29 μIU/mL; obeses: 3.08±1.13 μIU/mL), Free T3 (control: 2.19±0.63pg/dL; obeses: 2.09±0.34pg/dL), and Free T4 (control: 1.12±0.31ng/dL; obeses: 1.09±0.19ng/dL) concentrations were within the normal range in both groups, without significant difference between them (p>0.05). There was no correlation between thyroid hormone concentrations and zinc parameters (p>0.05). Although obese women presented hypozincemia, they had normal levels of thyroid hormones and no correlation was found between the studied parameters.

Low-Normal Thyroid Function Predicts Incident Anemia in the General Population With Euthyroid Status.

Thyroid hormones (THs) have direct and indirect effects on hematopoiesis. However, few studies have directly evaluated the effect of THs on incident anemia among euthyroid subjects. This cohort study aimed to explore whether THs under physiological conditions can affect the development of anemia in the general population. A total of 12,310 participants were enrolled in the cohort study (∼5-year follow-up period; mean, 3.1 years). A chemiluminescence immunoassay was used to measure free T3 (FT3), free T4 (FT4), and TSH, and anemia was defined according to the World Health Organization recommendation. THs, TSH, and Hb were assessed yearly during follow-up. Multivariable Cox proportional hazards regression models were used to assess the association between THs, TSH, and incident anemia. The fully adjusted hazards ratios (95% CI) of anemia per 1-unit change in FT3, FT4, and TSH concentrations were 0.70 (0.56, 0.87), 0.93 (0.88, 0.98), and 1.19 (0.94, 1.50) (P < 0.01, P < 0.01, and P = 0.14, respectively). Moreover, a significant and positive association between FT3, FT4, and annual changes in Hb (standard regression coefficients of 0.056 and 0.028, respectively; both P < 0.01) was observed. Similar associations were observed when the participants who had thyroid dysfunction upon follow-up were excluded. The current study demonstrated that THs significantly predict future anemia and annual changes in Hb, even in the euthyroid population.

PROGNOSTIC VALUE OF BIOCHEMICAL MARKERS IN PURULENT-CEPTIC COMPLICATIONS OF ACUTE SEVERE PANCREATITIS

One of the most pressing issues of urgent abdominal surgery is acute pancreatitis. The incidence of pancreatitis increases annually by 2.5 - 3.1%, ranging from 15 to 70 cases per 100,000 population in Europe and North America. About 40% of patients die within the first 7 days after hospitalization, most in the first 3 days. Patients with acute severe pancreatitis who are experiencing the first wave of the disease have a high risk of secondary infection of the pancreatic necrosis foci that is an indication for surgical intervention. This article presents the analysis of the treatment results in 22 patients with acute severe pancreatitis, 7 (31.8%) men and 15 (68.2%) women. Age of patients ranged from 22 to 79 years (46,9 ± 1,5 years). 2-7 days was the time from the onset of the disease to hospital admission. Purulent-septic complications developed in 22 (100.0%) patients, the presence of sequestrate was detected in 9 of them (40.9%). The average period of hospital staying for this group of patients was 48.3 ± 4.4 days; the mortality rate was 27.3% (6 patients). Having analyzing the biochemical markers obtained, we can state that the increase in the level of procalcitonin and C-reactive protein indicates the development of purulent-septic complications in patients with acute severe pancreatitis, while the decrease in the free T3 concentration at normal T4 and TSH levels in 6 (27.3%) of patients, suggests the development of their lowT3 syndrome that in turn suggests an unfavourable course of the disease.

Effects of PCB exposure on serum thyroid hormone levels in dogs and cats

Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) might disrupt thyroid function. However, there is no clear evidence of PCB exposure disrupting thyroid hormone (TH) homeostasis in dogs and cats. The present study conducted in vivo experiments to evaluate the effects of a mixture of 12 PCB congeners (CB18, 28, 70, 77, 99, 101, 118, 138, 153, 180, 187 and 202, each congener 0.5 mg/kg BW, i.p. administration) on serum TH levels in male dogs (Canis lupus familiaris) and male cats (Felis silvestris catus). In PCB-exposed dogs, the time courses of higher-chlorinated PCBs and L-thyroxine (T4)-like OH-PCBs (4-OH-CB107 and 4-OH-CB202) concentrations were unchanged or tended to increase, whereas those of lower-chlorinated PCBs and OH-PCBs tended to decrease after 24 h. In PCB-exposed cats, concentrations of PCBs increased until 6 h and then remained unchanged. The levels of lower-chlorinated OH-PCBs including 4′-OH-CB18 increased until 96 h and then decreased. In PCB-exposed dogs, free T4 concentrations were higher than those in the control group at 48 and 96 h after PCB administration and positively correlated with the levels of T4-like OH-PCBs, suggesting competitive binding of T4 and T4-like OH-PCBs to a TH transporter, transthyretin. Serum levels of total T4 and total 3,3′,5-triiodo-L-thyronine (T3) in PCB-exposed dogs were lower than in the control group at 24 and 48 h and negatively correlated with PCB concentrations, implying that PCB exposure enhanced TH excretion by increasing TH uptake and TH conjugation enzyme activities in the dog liver. In contrast, no obvious changes in TH levels were observed in PCB-exposed cats. This could be explained by the lower levels of T4-like OH-PCBs and lower hepatic conjugation enzyme activities in cats compared with dogs. Different effects on serum TH levels in PCB-exposed dogs and cats are likely to be attributable to species-specific PCB and TH metabolism.

Clinical Importance of Free Thyroxine Concentration Decline After Radiotherapy for Pediatric and Adolescent Brain Tumors.

Clinical significance of a decline in free T4 (FT4) concentrations across the reference range in children with brain tumors treated with radiation therapy (RT) is uncertain. To study trends in FT4 in children after RT and risk factors and health outcomes associated with plasma FT4 concentrations. Longitudinal, single-center retrospective cohort study. Low-grade glioma or ependymoma patients (n = 267; age ≤25 years) who received RT (50.4 to 59.4 Gy) at a single institution (1996 to 2016) and followed with serial FT4 measurements. A linear mixed-effects model with a random intercept was used to investigate risk factors for longitudinal changes in FT4 concentrations. A two-stage mixed-effects model examined associations between clinical outcomes and plasma FT4 concentrations. FT4 concentrations declined over time after RT (P < 0.001). Females (P < 0.001) and younger patients (P < 0.001) demonstrated greater declines in FT4 concentrations over time. The rate of weight gain, but not of height loss, increased with a higher FT4 decline rate (P < 0.001). At last follow-up, patients with lower baseline FT4 concentrations had increased risk of glucose disorder (OR, 19.73; P = 0.002) or dyslipidemia (OR, 19.40; P = 0.003) but not high fat mass (P = 0.18). Lower baseline FT4 concentrations were not associated with impaired scores for intelligence, attention, memory, or psychosocial functioning. FT4 concentrations significantly decline in children with brain tumor after RT. Variation and trends in FT4 concentration are associated with physical health outcomes. Future studies should assess whether continuous FT4 concentrations and trends, rather than population-based cut-off values, can distinguish between euthyroid and hypothyroid states.