Assessment of Thyroid Functions in Late Preterm Infants of Mothers on Antenatal Steroids

Purpose: The study examined the effect of antenatal steroids on thyroid functions in late preterm infants on the third to the seventh day of life. Patients and Methods: A comparative Cross-Sectional study was conducted on 75 neonates admitted to NICU in the first week of life. They were divided according to exposure to antenatal steroids into three groups. First group: exposed to complete course of ANS. Second group: exposed to partial course of ANS. The third group: not exposed to ANS. Serum samples were obtained from selected cases free T3, Free T4, and TSH levels in the third day of life, compared to the cut of levels currently available (the TSH reference range is (1.7 to 9.1 mU per L), T4 should be greater than( 10 mcg per dL). Using Eleusis and Cubase analyzers kits (Roche Diagnostics, Indianapolis, IN, USA) by ELISA (enzyme-linked immune sorbent assay) technique. Results: The study showed that there were significantly higher serum T4 levels in group 1 that was exposed to a complete course compared to group 2 (partial course) and 3 (Third group). There were no significant differences in serum TSH, T3 levels between groups. The current study found a decreased incidence of the ROP, NEC and BPD among group 1 as compared to the other two groups although was non statistically significant. In addition, the complete course of ANS had delayed the date of delivery (P=0.04) as compared to the partial course in the current study. Conclusion: Antenatal corticosteroids can influence thyroid function in late preterm infants as serum T4 was significantly higher in infants exposed to complete course compared to those who were exposed to partial course or did not receive antenatal corticosteroids.

EVALUATION OF THYROID PROFILE OF TERM AND PRETERM NEONATES AT 1ST AND 4TH WEEK AFTER BIRTH: A HOSPITAL BASED OBSERVATIONAL STUDY.

Objective: st th To evaluate the thyroid prole(T4,FT4 and TSH) in term and preterm neonates at 1 week after birth and during follow up at 4 week. Material and Method: This prospective observational hospital based study was conducted with 30 term(>37 completed week) and 30 preterm neonates(from 28 to 36 week 6days) with exclusion criteria of maternal thyroid disease or neonates with co-morbidity or signicant congenital st th anomalies. Serum T4,FT4 and TSH level were measured at 1 week and 4 week of postnatal age and results are analysed statistically. Results: st th We found TSH was elevated more in preterm than in term neonates in the 1 week, which decreased in both the groups at the 4 week . T4 st th and FT4 were signicantly higher in the term neonates than in preterm in the 1 week. During follow up in the 4 week, T4 and FT4 decreases in st term and increases in preterm so that the FT4 level almost matches in both the group at the end of 1 month. Conclusion: Our study shows that T4, FT4 and TSH has a signicant relationship with gestational age. Premature infants are born with higher th levels of TSH and lower levels of FT4 and T4 than term, which almost normalizes at 4 week.

Thyroid Function in Preterm/Low Birth Weight Infants: Impact on Diagnosis and Management of Thyroid Dysfunction

Maternal thyroid hormone crosses the placenta to the fetus beginning in the first trimester, likely playing an important role in fetal development. The fetal thyroid gland begins to produce thyroid hormone in the second trimester, with fetal serum T4 levels gradually rising to term. Full maturation of the hypothalamic-pituitary-thyroid (HPT) axis does not occur until term gestation or the early neonatal period. Postnatal thyroid function in preterm babies is qualitatively similar to term infants, but the TSH surge is reduced, with a corresponding decrease in the rise in T4 and T3 levels. Serum T4 levels are reduced in proportion to the degree of prematurity, representing both loss of the maternal contribution and immaturity of the HPT axis. Other factors, such as neonatal drugs, e.g., dopamine, and non-thyroidal illness syndrome (NTIS) related to co-morbidities contribute to the “hypothyroxinemia of prematurity”. Iodine, both deficiency and excess, may impact thyroid function in infants born preterm. Overall, the incidence of permanent congenital hypothyroidism in preterm infants appears to be similar to term infants. However, in newborn screening (NBS) that employ a total T4-reflex TSH test approach, a higher proportion of preterm babies will have a T4 below the cutoff, associated with a non-elevated TSH level. In NBS programs with a primary TSH test combined with serial testing, there is a relatively high incidence of “delayed TSH elevation” in preterm neonates. On follow-up, the majority of these cases have transient hypothyroidism. Preterm/LBW infants have many clinical manifestations that might be ascribed to hypothyroidism. The question then arises whether the hypothyroxinemia of prematurity, with thyroid function tests compatible with either non-thyroidal illness syndrome or central hypothyroidism, is a physiologic or pathologic process. In particular, does hypothyroxinemia contribute to the neurodevelopmental impairment common to preterm infants? Results from multiple studies are mixed, with some randomized controlled trials in the most preterm infants born <28 weeks gestation appearing to show benefit. This review will summarize fetal and neonatal thyroid physiology, thyroid disorders specific to preterm/LBW infants and their impact on NBS for congenital hypothyroidism, examine treatment studies, and finish with comments on unresolved questions and areas of controversy.

Prenatal Phthalates Exposure and Cord Thyroid Hormones: A Birth Cohort Study in Southern Taiwan

Background: The regulation of thyroid hormones in the early stages of gestation plays a crucial role in the outcome of a pregnancy. Furthermore, thyroid hormones are fundamental for the fetal development of all organs, including endocrine hormone changes in uterus. Endocrine disrupting chemicals have been shown to have an effect on thyroid hormone homeostasis in newborns, which affects their later development. Few studies have proposed how phthalates could alter thyroid function through several mechanisms and the possible effects on thyroid hormone homeostasis of phthalates on pregnant women. However, the effects of cord blood phthalates and prenatal phthalate exposure on thyroid hormones in newborns remain unclear. Objectives: We aim to follow up on our previous established subjects and determine the correlation between phthalate exposure and thyroid hormones in pregnant women and newborns. Materials and methods: We recruited 61 pregnant women from the Obstetrics and Gynecology Department of a medical hospital in southern Taiwan and followed up. High performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was used to analyze urine samples for five phthalate metabolites. Serum levels of thyroid hormones were analyzed using electrochemoluminescence immunoassay (ECLIA) method. We used Spearman and Pearson correlation coefficients to evaluate the correlation between each phthalate metabolites in serum and the thyroid hormone levels in fetus and parturient. Finally, multiple logistic regression was used to explore the relationship between hormones and their corresponding phthalate metabolites in cord blood. Results: High MBP in cord blood was correlated with negative cord serum TSH in newborns (r = −0.25, p < 0.06). By using multiple linear regression after adjusting for potential confounders (gestational and maternal age), cord serum MBP levels showed a negative association with cord serum TSH (β = 0.217, p < 0.05), cord serum T4 (β = 1.71, p < 0.05) and cord serum T4 × TSH (β = 42.8, p < 0.05), respectively. Conclusion: We found that levels of cord serum TSH and T4 in newborns was significantly negatively associated with cord serum MBP levels after adjusting for significant covariate. The fall in TSH in newborns may potentially be delaying their development.

Combined Effect of Monieziosis and Hypomicroelementosis on Some Hematological, Biochemical and Hormonal Parameters in Merino Sheep

This study was done to determine the impact of monieziosis infection combined with hypomicroelementosis on some hematological, biochemical and hormonal parameters of Soviet Merino sheep in the Astrakhan region. 20 sheep, aging 3 years old and average 43±1.6 kg body weight were used. Sheep were divided into two groups. First group contained 10 sheep and these sheep were naturally infected with monieziosis and clinically were suffered from hypomicroelementosis, emaciation, reduced growth rate, anemia, diarrhea and pale mucosa. Second group contained 10 sheep were apparently healthy and free from internal parasites and they were used as a control group. The first group was given Praziver (praziquantel and ivermectin) for treatment monieziosis, while they intramuscularly injected with Sedimin (selenium, iodine and iron) and were introduced daily into the feed with CoCl2. Faecal and blood samples from both groups were collected, before and 30 days after treatment, and analyzed for some hematological, biochemical and hormonal parameters. Our results revealed that there was a significant decrease in Hb and RBCs values, while total WBCs and eosinophils were significantly increased in the diseased group than in healthy one. Biochemical analysis showed a significant decrease in serum antioxidant enzymes (CAT, SOD and GSH-Px) and a significant increase in serum DC and MDA in the diseased group as compared with the control group. Hormonal analysis showed a significant increase in ACTH, TSH, Cortisol and a significant decrease in serum T4 and T3. After treatment with Praziver, Sedemin and CoCl2, there was a significant effectiveness to maintain blood parameters within normal levels in the experimental group and increase reproductive outcome from these sheep

Biological variation of total thyroxine (T4), free T4 and thyroid-stimulating hormone in 11 clinically healthy cats

Objectives The aim of this study was to investigate the biological variation of total thyroxine (T4), free T4 (fT4) and thyroid-stimulating hormone (TSH) in 11 clinically healthy cats aged between 3 and 15 years old, in Sydney, Australia. Methods Blood was collected weekly for up to 6 weeks and serum T4, fT4 and TSH concentrations were analysed using canine-specific reagents. Restricted maximum likelihood was used to estimate within-subject, between-subject and analytical variance components, which were recorded in terms of the related coefficients of variation. The index of individuality and reference change values were then calculated for each analyte. Results T4 and TSH had intermediate individuality, indicating both subject-based and population-based reference intervals (RIs) could be used, with the knowledge that population-based RIs are suboptimally sensitive. fT4 had high individuality, indicating subject-based RIs are more appropriate than population-based RIs. Conclusions and relevance This study has demonstrated that subject-based RIs could be more sensitive than population-based RIs for the diagnosis of thyroid dysfunction in cats.

Associations of multiple serum biomarkers and the risk of cardiovascular disease in China

Background Previous studies focus on one or several serum biomarkers and the risk of cardiovascular disease (CVD). This study aims to investigate the association of multiple serum biomarkers and the risk of CVD and evaluate the dose-relationship between a single serum metabolite and CVD. Methods Our case-control study included 161 CVD and 160 non-CVD patients who had a physical examination in the same hospital. We used stratified analysis and cubic restricted analysis to investigate the dose-response relationship of individual serum biomarkers and the CVD incident. Moreover, to investigate serum biomarkers and CVD, we used elastic net regression and logistic regression to build a multi-biomarker model. Results In a single serum biomarker model, we found serum FT4, T4. GLU, CREA, TG and LDL-c were positively associated with CVD. In the male group, serum T4, GLU and LDL-c were positively associated with CVD; and serum TG was positively associated with CVD in the female group. When patients ≤63 years old, serum T4, GLU, CREA and TG were positively associated with CVD, and serum TG and LDL-c were positively associated with CVD when patients > 63 years old. Moreover, serum GLU had nonlinearity relationship with CVD and serum TG and LDL-c had linearity association with CVD. Furthermore, we used elastic regression selecting 5 serum biomarkers (GLU, FT4, TG, HDL-c, LDL-c) which were independently associated with CVD incident and built multi-biomarker model. And the multi-biomarker model had much better sensitivity than single biomarker model. Conclusion The multi-biomarker model had much higher sensitivity than a single biomarker model for the prediction of CVD. Serum FT4, TG and LDL-c were positively associated with the risk of CVD in single and multiple serum biomarkers models, and serum TG and LDL-c had linearity relationship with CVD.

The study of correlation between thyroid function and blood pressure in hypertensive patients attending out patient department in tertiary care centre

Background: Hypertension may be the initial clinical presentation for at least 15 endocrine disorders, including overt and subclinical hyperthyroidism and hypothyroidism. The correction of thyroid dysfunction may normalize Blood Pressure (BP) in most cases, therefore checking thyroid function is essential during the workup for hypertension. The present study was conducted to find out the association between hypertension and thyroid dysfunction.Methods: It was a retrospective, observational study conducted among patients having hypertension visiting the outpatient department of Medicine in KIMS Karad, during the period of 2 months.Results: The mean values of various thyroid function parameters among hypertensive cases was assessed in the current study, Authors found that the mean Serum T3 level was 93.5917±32.82, Mean Serum T4 level was 6.72±1.64 and the mean Serum TSH level was 2.52±2.71. Among all the cases about 52% cases had deranged thyroid function reports.Conclusions: The results of this study suggest an association between subclinical hypothyroidism and increased blood pressure levels.

Extrapolating In Vitro Screening Assay Data for Thyroperoxidase Inhibition to Predict Serum Thyroid Hormones in the Rat

Thyroperoxidase (TPO) is an enzyme essential for thyroid hormone (TH) synthesis and a target site for a number of xenobiotics that disrupt TH homeostasis. An in vitro high-throughput screening assay for TPO inhibition, the Amplex UltraRed-TPO (AUR-TPO), has been used to screen the ToxCast chemical libraries for this action. Output from this assay would be most useful if it could be readily translated into an in vivo response, namely a reduction of TH in serum. To this end, the relationship between TPO inhibition in vitro and serum TH decreases was examined in rats exposed to 2 classic TPO inhibitors, propylthiouracil (PTU) and methimazole (MMI). Serum and gland PTU, MMI, and TH levels were quantified using tandem liquid chromatography mass spectrometry. Thyroperoxidase activity was determined in thyroid gland microsomes treated with PTU or MMI in vitro and ex vivo from thyroid gland microsomes prepared from exposed animals. A quantitative model was constructed by contrasting in vitro and ex vivo AUR-TPO results and the in vivo time-course and dose-response analysis. In vitro:ex vivo correlations of AUR-TPO outputs indicated that less than 30% inhibition of TPO in vitro was sufficient to reduce serum T4 by 20%, a degree of regulatory significance. Although further testing of model estimates using other TPO inhibitors is essential for verification of these initial findings, the results of this study provide a means to translate in vitro screening assay results into predictions of in vivo serum T4 changes to inform risk assessment.