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At least 19 recordsLinked to original sources
PubMed2003

Prevalence of multivessel coronary artery disease in patients with diabetes mellitus plus hypothyroidism, in patients with diabetes mellitus without hypothyroidism, and in patients with no diabetes mellitus or hypothyroidism.

BACKGROUND: We report the prevalence of significant multivessel coronary artery disease (CAD) (>50% stenosis) in patients with diabetes plus hypothyroidism, in patients with diabetes without hypothyroidism, and in patients without diabetes or hypothyroidism who had significant CAD documented by coronary angiography. METHODS: We performed a retrospective analysis in 100 patients selected randomly with significant CAD documented by coronary angiography to investigate the prevalence of significant multivessel CAD in patients with diabetes, in patients with hypothyroidism, and in patients without diabetes or hypothyroidism. RESULTS: Significant 3-4-vessel CAD was present in 9 of 10 patients (90%), mean age 73 +/- 11 years, with diabetes plus hypothyroidism, in 10 of 25 patients (40%), mean age 63 +/- 9 years, with diabetes without hypothyroidism, and in 10 of 65 patients (15%), mean age 68 +/- 12 years, without diabetes or hypothyroidism (p <.001 comparing diabetes plus hypothyroidism with no diabetes or hypothyroidism; p <.01 comparing diabetes plus hypothyroidism with diabetes without hypothyroidism; and p <.02 comparing diabetes without hypothyroidism with no diabetes or hypothyroidism). Significant 2-4-vessel CAD was present in 10 of 10 patients (100%) with diabetes plus hypothyroidism, in 20 of 25 patients (80%) with diabetes without hypothyroidism, and in 37 of 65 patients (57%) with no diabetes or hypothyroidism (p <.01 comparing diabetes plus hypothyroidism with no diabetes or hypothyroidism; and p <.05 comparing diabetes without hypothyroidism with no diabetes or hypothyroidism). CONCLUSIONS: In patients with diabetes mellitus plus hypothyroidism, the prevalence of 3-vessel or 4-vessel CAD was significantly higher than in patients with diabetes mellitus without hypothyroidism or in patients with no diabetes mellitus or hypothyroidism. In patients with diabetes mellitus without hypothyroidism, the prevalence of 3-vessel or 4-vessel CAD was significantly higher than in patients without diabetes mellitus or hypothyroidism.

Age Distribution↗
PubMed2004

Contributions of bone maturation measurements to the differential diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism.

AIM: To a) evaluate the contribution of bone maturation in the diagnosis of neonatal transient hypothyroidism versus dyshormonogenetic congenital hypothyroidism in full-term newborns, and b) use bone maturation to test the hypothesis that neonatal transient hypothyroidism is perinatal in onset. MATERIALS AND METHODS: The study included 20 patients with dyshormonogenetic and 43 with transient hypothyroidism. Thyroid function and measurements of the distal femoral epiphysis area, obtained at the time of first confirmatory diagnosis, were compared between the two groups. The epiphysis area in two control groups with normal thyroid function was also measured and compared with that in patients with transient hypothyroidism, at age 1-3 d (control A), or at the age when normal thyroid function was confirmed (control B). RESULTS: Mean epiphysis area was 0.04 cm2 in patients with dyshormonogenetic versus 0.22 cm2 in patients with transient hypothyroidism (p < 0.0001). An area <0.05 cm2 was limited to patients with dyshormonogenetic hypothyroidism. Conversely, a normal area (>0.2 cm2) was only observed in patients with transient hypothyroidism. Mean epiphysis areas in control A (0.20 cm2) and in patients with transient hypothyroidism were similar (p = 0.37), consistent with perinatal onset of transient hypothyroidism. Mean epiphysis area in control B (0.31 cm2) was significantly greater than in patients with transient hypothyroidism (p < 0.01). CONCLUSIONS: A short duration of hypothyroidism can significantly delay bone maturation. Examination of bone maturation at initial confirmatory evaluation yields important information pertaining to congenital hypothyroidism, not only to predict intellectual development, but also to evaluate the risk of dyshormonogenetic hypothyroidism.

Bone Development↗
PubMed1996

Morphometric study on the uterine horn and thyroid gland in hypothyroid, and thyroxine treated hypothyroid rats.

A wide range of reproductive disorders such as irregular menstruation and frank infertility is found in women with hypothyroidism. Most research done on these patients has focused on steroid and gonadotropin hormone profiles, whilst there has been little work on uterine morphology. Studies on hypothyroid animals have also demonstrated increases in fetal wastage, but there have been few studies of uterine structure in the hypothyroid rat. The present study has used hypothyroid Wistar rats as a model for investigating the effects of hypothyroidism on uterine structure. Three groups of Wistar rats were studied. One was made hypothyroid with methimazole (MMI), the 2nd was also made hypothyroid with methimazole but in addition the rats were simultaneously given daily thyroxine intraperitoneally (MMI + T4), and the 3rd was an untreated euthyroid group (control). Daily vaginal smears were obtained from rats in all 3 groups. All rats were aged 6 wk at the start of treatment and were killed after a further 6 wk. Uterine horns were removed and studied. Systematic random transverse sections were obtained from the proximal, middle, and distal regions of the horn and subjected to morphometric analysis. Difference between regions was assessed using 2-way analysis of variance. Absolute volume of endometrium in the uteri of hypothyroid rats was reduced by 45.1% (P < 0.05), whilst that of the muscle layer was decreased by 33.6% (P < 0.05). The cross-sectional area and absolute volume of the uterine horns were also reduced in hypothyroid animals (P < 0.05). In hypothyroid rats given thyroxine (MMI + T4) all variables increased significantly above those of hypothyroid rats. These changes suggest that hypothyroidism has an effect on uterine structure, which demonstrably improves under exogenous thyroxine administration. The observed structural changes might well play a significant role in the reproductive difficulties observed during hypothyroidism.

Analysis of Variance↗
PubMed1992

Increased arterial and venous plasma noradrenaline levels in patients with primary hypothyroidism during hypothyroid as compared to euthyroid state.

The use of venous plasma noradrenaline levels as a marker of general sympathetic tone has been questioned as changes in local sympathetic activity may influence the venous levels. To compare arterial and venous plasma noradrenaline levels in patients with primary hypothyroidism, arterial and venous blood were sampled during strictly standardized conditions during hypothyroid and euthyroid states. The patients were hospitalized for 5 days at a metabolic ward on a standardized sodium and potassium intake. On the fourth day catheters were positioned in the axillary artery and vein. Blood samples were drawn simultaneously for noradrenaline and adrenaline determinations during resting conditions. The arterial and venous plasma noradrenaline levels did not differ significantly, neither during hypothyroidism nor during euthyroidism. The arteriovenous difference in plasma adrenaline was similar during hypothyroidism compared to euthyroidism, indicating similar peripheral extraction rate of catecholamines during hypothyroidism as compared to euthyroidism. During hypothyroidism venous and arterial noradrenaline were significantly higher as compared to euthyroidism. In conclusion, there is no difference between arterial and venous noradrenaline levels either in the hypothyroid or the euthyroid state, and the peripheral extraction rate of plasma noradrenaline seems to be similar in hypothyroidism and euthyroidism. The local contribution of noradrenaline from the arm, reflecting local sympathetic nervous activity, is limited during resting conditions. In hypothyroid patients plasma noradrenaline levels are increased as compared to the euthyroid state, indicating increased general sympathetic activity in hypothyroidism.

Adult↗
PubMed1982

Secretion of nascent lipoproteins by isolated hepatocytes from hypothyroid and hypothyroid, hypercholesterolemic rats.

The induction of hypothyroidism in the rat is necessary for the development of pronounced dietary-induced hypercholesterolemia. The nature of nascent lipoproteins secreted by isolated hepatocytes from euthyroid, hypothyroid and hypothyroid, cholesterol-fed rats was investigated to distinguish between these hormonal and dietary effects. Serum total lipids, apolipoproteins, B, E and A-I, were greatly elevated in hypercholesterolemia. In hypothyroidism, serum apolipoproteins B and E were elevated, triacylglycerols were reduced by 65% and free cholesterol was increased by 50%. The total lipid, apolipoprotein B and E, secreted by hypercholesterolemic rat hepatocytes was markedly elevated when compared to normal. Triacylglycerol and phospholipid secretion was slightly increased by hypothyroid rat hepatocytes; however, apolipoprotein B, E and A-I secretion rates were unaffected. Gel filtration of the nascent lipoproteins demonstrated that compared to normal, proportionately more apolipoprotein B and E from hypercholesterolemic rat hepatocytes and apolipoprotein E from hypothyroid rat hepatocytes was secreted as larger lipoproteins. Hypercholesterolemic rat hepatocytes secreted abnormal cholesterol-rich particles even after 24 h of incubation in a lipid-deficient medium. Hypothyroidism alone cannot account for this observation, as hypothyroid rat hepatocytes secreted a triacylglycerol-rich, cholesterol-deficient lipoprotein having a normal nascent lipoprotein lipid composition. These observations are consistent with the hypothesis that in hypothyroidism the accumulation of beta-migrating lipoproteins results from impaired removal of lipoprotein catabolites from the serum, a condition which would only promote hypercholesterolemia in cholesterol feeding where direct synthesis of abnormal lipoproteins occurs.

Animals↗
PubMed1994

Quantitative [3H]thymidine autoradiography of neurogenesis in the olfactory epithelium of developing normal, hypothyroid and hypothyroid-rehabilitated rats.

We recently reported that postnatal hypothyroidism results in marked reduction in surface area and cell number in the rat olfactory epithelium (OE) and recovery from this condition is accompanied by compensatory growth and restitution of these parameters. To explore the correlative changes in olfactory neurogenesis, i.e. mitotic activity of basal cells (BCs) and migration and survival of developing olfactory receptor neurons (ORNs), hypothyroid rats at postnatal (P) days of P10, P25 and P75 were injected with [3H]thymidine and OE was examined by quantitative autoradiography to determine the density of labeled nuclei at the BC and ORN zones at days 1, 5 and 15 post-injection. These data were compared with those of age-matched controls as well as young adult rats allowed to recover from hypothyroidism at the end of the suckling period (P25). Hypothyroidism was induced by administration of propylthiouracil (PTU) from birth in the drinking water (1 g/l) for 10, 25 and 90 days; recovery was induced by withdrawal of PTU at P25. The results indicated that the densities of labeled nuclei in the BC and ORN zones were not significantly altered in the suckling hypothyroid rats. In the P75 hypothyroid rats density of labeled BC nuclei was unaffected 1 day after injection but was significantly (36%) more than controls 5 days after injection; the density of neuronal nuclei in the ORN zone of P75 injected rats was markedly and significantly reduced (56% and 37% at 5- and 15-days post-injection). Data indicate that mitotic activity of BCs and their migration into the ORN zone is not affected in the hypothyroid infant rats but migration and/or survival of developing ORNs are markedly reduced in the postweaning growing rats made hypothyroid from birth. In rats allowed to recover from hypothyroidism at P25 and injected with labeled thymidine at P75, the density of labeled BC nuclei were significantly increased (48% and 43% at 1- and 5-days post-injection) compared to normal rats suggesting elevated levels of neurogenesis; density of ORN nuclei, however, were the same as controls. The results indicate critical regulatory influences of thyroid hormones on olfactory neurogenesis in the rat olfactory receptor sheet, in particular during the postweaning period.

Animals↗
PubMed1997

Estimation of tissue hypothyroidism by a new clinical score: evaluation of patients with various grades of hypothyroidism and controls.

The classical signs and symptoms of hypothyroidism were reevaluated in the light of the modern laboratory tests for thyroid function. We analyzed 332 female subjects: 50 overt hypothyroid patients, 93 with subclinical hypothyroidism (SCH), 67 hypothyroid patients treated with T4, and 189 euthyroid subjects. The clinical score was defined as the sum of the 2 best discriminating signs and symptoms. Beside TSH and thyroid hormones, we measured parameters known to reflect tissue manifestations of hypothyroidism, such as ankle reflex relaxation time and total cholesterol. Classical signs of hypothyroidism were present only in patients with severe overt hypothyroidism with low T3, but were rare or absent in patients with normal T3 but low free T4 or in patients with SCH (normal thyroid hormones but elevated basal TSH; mean scores, 7.8 +/- 2.7 vs. 4.4 +/- 2.2 vs. 3.4 +/- 2.0; P < 0.001). Assessment of euthyroid subjects and T4-treated patients revealed very similar results (mean score, 1.6 +/- 1.6 vs. 2.1 +/- 1.5). In overt hypothyroid patients, the new score showed an excellent correlation with ankle reflex relaxation time and total cholesterol (r = 0.76 and r = 0.60; P < 0.0001), but no correlation with TSH (r = 0.01). The correlation with free T4 was r = -0.52 (P < 0.0004), and that with T3 was r = -0.56 (P < 0.0001). In SCH, the best correlation was found between the new score and free T4 (r = -0.41; P < 0.0001) and TSH (r = 0.35; P < 0.0005). Evaluation of symptoms and signs of hypothyroidism with the new score in addition to thyroid function testing is very useful for the individual assessment of thyroid failure and the monitoring of treatment.

Adult↗
PubMed2006

A morphometric study on the endometrium of rat uterus in hypothyroid and thyroxine treated hypothyroid rats.

Hypothyroidism increases the rate of pregnancy loss. Other manifestations include menstrual disorder, and infertility. Serum levels of gonadotropins are low in hypothyroid patients. Though studies of uterine ultrastructure are well established as approaches to investigating the pathophysiology of infertility, they have scarcely been extended to the study of hypothyroid related infertility. The present study investigates the effect of hypothyroidism on the ultrastructure of uterine epithelium. Three groups of Wistar rats were studied. Two groups were initially made hypothyroid using methimazole, and the third group was an untreated control. One hypothyroid group was given daily injections of thyroxine for six weeks. The uteri were removed in all three groups, and processed for transmission electron microscopy and morphometry. It was found that absolute epithelial cell volume was decreased in hypothyroidism. The volume of the nucleus had decreased though its relative volume in the cell had increased. The height of the luminal epithelium in hypothyroid rats also decreased by (33.8%) as compared with controls. Basement membrane thickness was significantly increased in hypothyroidism. The changes were all substantially abrogated by the administration of thyroxine. This study suggests that thyroid hormones might be importantly concerned in the maintenance of the normal structure of uterine epithelial cells.

Animals↗
PubMed1979

Pituitary-thyroid function of fetuses of hypothyroid and growth hormone treated hypothyroid rats.

Maternal hypothyroidism induced by surgical thyroidectomy (Tx) of the rat resulted in significantly higher fetal serum levels of thyroid stimulating hormone (TSH) and thyroxine (T4) on day 22 of gestation. Surprisingly, administration of growth hormone (GH) to hypothyroid mothers increased further the fetal serum T4 and TSH. The in vitro uptake of 131I-T4 by erythrocytes was elevated significantly when incubated with serum from fetuses of both hypothyroid and hypothyroid GH-treated mothers. Although the plasma protein levels of hypothyroid mothers and their fetuses are decreased significantly as compared to controls this is not true of hypothyroid GH-treated mothers and their fetuses. The T4 levels of both groups of Tx mothers were significantly below that of controls. However, as in the case of their fetuses, the serum T4 of GH-treated hypothyroid mothers was elevated from that of Tx only animals. It is concluded that the pituitary-thyroid system of fetuses of hypothyroid mothers is activated excessively during late gestation, that considerable T4 can be transported from the fetus to the mother during this period and that these fetuses are in fact born in a hyperthyroid state which is aggravated by maternal treatment with GH.

Animals↗
PubMed2004

Prolonged P300 latency in thyroid failure: a paradox. P300 latency recovers later in mild hypothyroidism than in severe hypothyroidism.

This study was performed to analyze quantitatively the cognitive functions of patients with mild and severe hypothyroidism by measuring P300 event-related evoked potentials before and after euthyroidism was established. Patients diagnosed as having Hashimato's thyroiditis with thyroid stimulating hormone (TSH) levels between 5 and 10 mU/L (mild thyroid failure; n = 24) and those with severe hypothyroidism (n = 13) were enrolled randomly to the study protocol. P300-event related potentials were recorded during thyroid insufficiency, and in the first and sixth month of euthyroidism. P300 latencies were prolonged in both the mild and severe hypothyroid patients compared to controls (p = 0.042, p < 0.001, respectively). The overt hypothyroid patients showed significant decrease in their P300 latencies after the first month of euthyroidism (p = 0.001). These P300 latency values did not differ in the subsequent 6-month period. The mild hypothyroid group, however, displayed no improvement of P300 latency in the first month but normalized at the sixth month of euthyroidism. In conclusion, both the overt and the mild hypothyroid patients revealed prolonged P300 latencies. Unexpectedly, P300 latencies in the patients with mild thyroid failure required more time to recover compared to the overt hypothyroid patients. This finding indicates different clinical outcomes of various thyroid insufficiency states on the brain.

Adult↗
PubMed1994

Primary hypothyroidism manifested in childhood with special reference to various types of reversible hypothyroidism.

The clinical course of 15 patients with overt primary hypothyroidism manifested in childhood were studied. Nine female patients with goitrous hypothyroidism due to chronic thyroiditis showed almost normal height and became euthyroid spontaneously during iodine restriction. The other 6 nongoitrous patients (3M and 3F) (atrophic thyroiditis in 2, lingual goiter in 2 and probable hypoplastic thyroid in 2) showed physical growth retardation and remained irreversibly hypothyroid requiring replacement therapy. In the reversible group, the characteristic findings were high thyroidal radioactive iodine uptake (58 +/- 19%/24 h, N = 8) and positive perchlorate discharge test. Serum nonhormonal iodine levels were high in 4 of 6 patients measured. During the long-term follow-up period of 6 years in 6 patients, 2 patients remained euthyroid with normal growth and regular menstrual cycle and 4 patients became hypothyroid again (after eating seaweed in 1, despite iodine restriction in 2 and after the episode of painless thyroiditis in 1). Transient retardation of growth was observed during the second episode of hypothyroidism. In the irreversible group, one patient with blocking type TSH binding inhibitor immunoglobulin (TBII) became thyrotoxic 4 years later with the decrease in activity of blocking type TBII. These results suggested that reversible recovery of the thyroid function could be expected in patients with juvenile hypothyroidism due to chronic thyroiditis after (1) iodine restriction, (2) improvement of immunological perturbation, or (3) disappearance of blocking type TBII. However, careful follow-up is necessary, because hypothyroidism would recur again with transient retardation of growth in children.

Adolescent↗
PubMed1987

Hypothyroidism and the heart. Examination of left ventricular function in subclinical hypothyroidism.

For revealing whether cardiac performance is changed in subclinical hypothyroidism, the left ventricular ejection fraction (LVEF), a value characterizing left ventricular function, was studied in this clinical state. The results were compared to those obtained in euthyroid subjects and patients with overt hypothyroidism. In a part of subclinical cases, there is a subnormal resting LVEF, which on isometric exercise, increases, but to a lesser extent than in euthyroid controls. In overt hypothyroidism resting LVEF is considerably lower than in euthyroid and subclinically hypothyroid subjects and its value does not respond to exercise. There has been evidence that heterogeneous subclinical hypothyroidism is an intermediate state between euthyroidism and overt hypothyroidism; the majority of patients are euthyroid, a part of them, however, based on systolic time intervals and LVEF studies, are suspect of developing 'tissue' hypothyroidism, although their serum thyroid hormone level is still within normal limits.

Adult↗
PubMed2002

Hypothalamo-pituitary hypothyroidism detected by neonatal screening for congenital hypothyroidism using measurement of thyroid-stimulating hormone and thyroxine.

UNLABELLED: The optimal strategy in neonatal screening for congenital hypothyroidism is still a subject of controversy. In Kanagawa Prefecture in Japan, simultaneous thyroid-stimulating hormone (TSH) and T4/fT4 determination has been used, while the results of our program may provide valuable information. Cumulative findings were analysed to determine the type and frequency of thyroid disorders in infants detected by simultaneous TSH and T4/fT4 determination, and the TSH and T4/fT4 screening strategy was validated. A total of 1284130 neonates were screened between October 1979 and September 1997 and infants followed because of low T4/fT4 without elevated TSH (T4 < 51.5 nmol/L or fT4 < 9 pmol/L and TSH < 15 mU/L) were retrospectively analysed. The first survey was carried out within 6 mo of birth and the second in 1998; 258 infants were diagnosed with congenital hypothyroidism at the first medical evaluation, 15 of them with hypothalamo-pituitary hypothyroidism. However, in the second survey, only 8 children were confirmed as having hypothalamo-pituitary hypothyroidism, therefore the incidence detected by the present strategy was 1/160516. Of 8 children with hypothalamo-pituitary hypothyroidism, mental retardation was prevented in 3 owing to early treatment. CONCLUSIONS: Simultaneous measurement of TSH and T4/fT4 is a useful strategy for detecting hypothalamo-pituitary hypothyroidism, but more studies are needed to show the cost-benefits of using this strategy.

Congenital Hypothyroidism↗
PubMed2004

Evaluation of experimental methods to induce congenital hypothyroidism in guinea pigs for use in the study of congenital hypothyroidism in horses.

OBJECTIVE: To develop a method to reliably induce congenital hypothyroidism in guinea pigs (Cavia porcellus) and assess similarities between the resultant developmental abnormalities and those described in horses with congenital hypothyroidism. ANIMALS: 35 female guinea pigs and their offspring. PROCEDURE: Guinea pigs were allocated to control groups or groups treated with a low-iodine diet before and throughout gestation; an s.c. injection of 100 or 200 microCi of radioactive iodine 131 (131I) on day 40 of gestation; or 0.1% propylthiouracil (PTU) continuously in the drinking water, beginning day 3 or 40 of gestation. In all groups, assessments included gestation duration, litter size, proportion of stillborn pups, and laboratory analyses in live pups and dams; postmortem examinations were performed on all pups and dams and selected tissues were examined histologically. RESULTS: Compared with control animals, pups from dams receiving a low-iodine diet or 131I s.c. had mild changes in their thyroid glands but no grossly or radiographically detectable lesions of hypothyroidism. Pups from dams receiving PTU were often stillborn (24/27 pups) and had enlarged thyroid glands (characterized by large, variably sized follicles of tall columnar epithelium and little or no colloid), an incomplete coat, and radiographically detectable skeletal dysgenesis. CONCLUSIONS AND CLINICAL RELEVANCE: Many of the lesions detected in guinea pig pups from the experimentally treated dams were similar to those described in foals with congenital hypothyroidism. Experimental induction of congenital hypothyroidism in guinea pigs may be useful for the study of naturally occurring congenital hypothyroidism in horses.

Animals↗
PubMed1990

Influence of hypothyroidism and the reversal of hypothyroidism on hemodynamics and cell size in the adult rat heart.

Hypothyroid-induced atrophy of cardiac myocytes was examined in adult female rats in an effort to correlate hemodynamic and cellular changes associated with this disorder. Additional rats were studied 6 weeks after discontinuing antithyroid treatment to determine if structural and functional changes were completely reversible. To induce hypothyroidism, rats were injected daily with propylthiouracil (PTU) for 4 weeks. Control animals were injected similarly with Tris buffer. At the end of the treatment period, hemodynamic measurements were made prior to obtaining isolated myocytes. Cell volume, length, and cross-sectional area were obtained from the septum, and left and right ventricles of treated and untreated rats. After four weeks treatment with PTU, body weight was unchanged but heart weight was significantly reduced by 24%. Characteristic hemodynamic changes associated with hypothyroidism in the rat were noted (eg. reduced heart rate, cardiac output, dP/dtmax, and ventricular pressure). Cell volume was significantly smaller in hypothyroid rats primarily due to a reduction in myocyte cross-sectional area. The hemodynamic and cellular response to hypothyroidism was similar in the right and left ventricle. Six weeks after discontinuing PTU treatment, cellular and hemodynamics changes had returned to normal. It was concluded that hypothyroidism caused a true cardiac atrophy which was reversible. Reduced myocyte cross-sectional area was responsible for most of the myocyte atrophy.

Animals↗
PubMed1978

Difference in pituitary-thyroid feedback regulation in hypothyroid patients, depending on the severity of hypothyroidism.

In an attempt to study pituitary-thyroid interplay during replacement therapy for hypothyroidism, T4 (75-150 micrograms/day) was administered for at least 3 months. A small dose of T4 (75 micrograms/day) significantly depressed basal and TRH-stimulated TSH levels in normal subjects without significantly elevating serum T4 and T3 concentrations. In patients with severe hypothyroidism and marked enlargement of the sella turcica, T4 (2.53 micrograms/kg BW) normalized the serum T4 and slightly elevated the serum T3 but failed to normalize basal and TRH-stimulated TSH levels. In patients with moderate hypothyroidism and moderate enlargement of the sella turcica, T4 (2.0 micrograms/kg BW) normalized serum T4, T3, and basal TSH concentrations but failed to normalize TRH-stimulated TSH levels. In patients with slight hypothyroidism and slight enlargement of the sella turcica, T4 (1.84 micrograms/kg BW) normalized serum T4, T3, and TSH (both basal and TRH stimulated) concentrations. In five patients, an apparent paradoxical increase of basal serum TSH level was found shortly after starting thyroid hormone treatment. It is suggested that pituitary-thyroid interplay during the first 3-6 months of replacement therapy for hypothyroidism varies greatly depending on the severity of hypothyroidism.

Adult↗
PubMed2003

Congenital hypothyroidism and iodine status in Turkey: a comparison between the data obtained from an epidemiological study in school-aged children and neonatal screening for congenital hypothyroidism in Turkey.

BACKGROUND: Congenital hypothyroidism and endemic iodine deficiency are the most common cause of mental retardation. However in both cases retardation is of nonpreventable nature. OBJECTIVE: The aim of the study was to investigate whether epidemiological study in school-aged children or neonatal screening of congenital hypothyroidism (CH) was useful to assess iodine status and monitor the preventive measures of iodine deficiency disorders (IDD). SUBJECTS: To study the epidemiology, 1046 school children, aged 8 to 12 years from 23 primary schools in rural and urban areas from three cities in Turkey were included. Neonatal screening for congenital hypothyroidism (CH) was carried in. METHODS: Goiter and thyroid volume were assessed by palpation and ultrasound, respectively. Thyroid stimulating hormone (TSH), total thyroxine (T4), and urinary iodine excretion (UIE) were measured. Neonatal screening for CH was adjusted according to the guidelines of Pediatric Endocrinology of the European Society for Pediatric Endocrinology. RESULTS: There was no significant difference between the median TSH in school-aged children and the cities of Bolu and Duzce (p>0.05). Median TSH of Zonguldak was significantly different from the median TSH of Bolu (p=0.046) and Düzce (p=0.028). There was no significant difference between the median T4 levels of Bolu and Duzce (p>0.05). The median T4 of Zonguldak showed a significant difference from the median T4 value of Bolu (p=0.018), but an insignificant difference from the median T4 of Duzce (p>0.05). The overall goiter prevalence in 1046 children was 52%. In two years, 18606 newborns were screened. With a cut-off point at TSH >20 microm U/ml, the recall rate was 1.6% and the incidence of CH 1/2326. There was 26.7% children with TSH >5 microm U/ml. Both data of the epidemiological study in school-aged children and neonatal screening for CH indicated that the West Black Sea Region is affected by mild to moderate iodine deficiency. CONCLUSION: the implementation of neonatal screening for congenital hypothyroidism using TSH measurement has many advantages. It can detect congenital hypothyroidism and transient primary hypothyroidism, and can also be used for monitoring tools of preventive measures of IDD. Countries, such as Turkey, which has not begun national screening for CH yet, should make implementation of neonatal screening for CH using primary TSH measurement a political priority.

Biomarkers↗