[Thyroid functional activity and hemodynamic parameters in upper-class schoolchildren presenting with endemic goiter]

We studied the relationship between iodine deficiency, blood cortisol levels, andhemodynamicparameters in 536schoolchildren of Vladikavkaz aged 13-17 years. Urine iodine was measured using cerium arsenite reaction, thyroid function was evaluated from thyrotropin, T3, and free T4 levels, blood cortisol was determined by the immonoenzyme assay using Alcor Bio kits. The study group included 24 subjects with endemic goiter, control group was comprised of 14 healthy adolescents. Hemodynamic parameters were studied using a Vivid 7 Dimension scanner.

Iconography of goiter: four refined examples in the Sacred Mountain of Varese, Italy

BACKGROUND

Four goiter representations observed by the authors in the sculptures of the Sacred Mountain of Varese, Italy, are described here.

SUMMARY

They should be regarded as a typical and proper example of the iconography of "real goiter," where the artists had the definite intention to depict persons with goiter.

CONCLUSIONS

Studies of representations of individuals with goiter are not that rare, even though most of the observations reported in the literature deal with images that should be considered occasional swelling of the anterior neck, "thick neck," or "pseudogoiter" because the artists probably did not have any intention to illustrate the pathological condition.

[Brain bioelectric activity forming in adolescents living in different endemic goiter area of European North]

Northern European regions are goiter endemic and iodine-deficient areas, and also differ in the degree of extreme weather conditions in the Polar and Subpolar latitudes. The age formation of the nervous system in adolescents depends on these discomfort climatic factors.

AIM

The study of functional brain activity depending on the thyroid profile in adolescents living in the European North.

PATIENTS AND METHODS

211 adolescents (male and female) aged 15-16 years living in the Subpolar (64 degrees 30' N) and Polar (67 degrees 40' N) Russian regions were observed. An electroencephalogram in a state of quiet wakefulness with eyes closed monopolar 16 standard leads was recorded. Electroencephalogram characteristic were performed by the values: of the wave amplitudes, index and absolute spectral power in each frequency band: 4-7 Hz, 8-12 Hz and 13-24 Hz. In serum samples by immune-enzyme assay thyrotropin, triiodothyronine and thyroxine levels were determined. All the described changes were statistically significant at p < 0.05-0.001.

RESULTS

A higher activity of diencephalic subcortical brain structures, expressed in the form of increased -activity and photic driver reactions were determined in adolescents living in Polar region. Background thyroid status determines the age formation of brain activity. In adolescents living in the Polar region a high concentration of thyrotropin in the blood and the availability of significant relations with thyroid hormones levels with a brain theta-activity were detected. In adolescents living in Subpolar region is more intense age optimization of neural processes, as well as the greatest number of neuro-endocrine relationships.

[Peculiarities of formation, clinical presentations and therapy of diffuse nontoxic goiter of children]

The paper deals with the peculiarities of formation, clinical presentations and therapy of diffuse nontoxic goiter of children. The paper highlights the connection of the disease with the genetic predisposition, the impact of natural and anthropogenic strumagenes, immune processes. The clinical presentations of the diffuse nontoxic goiter are diffuse enlargement of thyroid gland, normal or high level of thyrotropichypophysis hormone when the content of thyroxin and triiodothyronine is normal, which is treated as the subclinic hypothyroidism syndrome. The variety of the disease pathogenesis theories leads to testing of different therapeutic methods, the principal ones among them are the use of iodine preparation and replacement therapy.

[Neuroendocrine, neorophysiological and neuropsychological changes in children form the iodine deficient population with endemic goiter]

The study was performed in Chokhatauri region, on students of age 13-14 in village Meria in 36 schools. There is discovered mild iodine deficiency with median variation from 78 to 96 %. After clinical and ultrasound studies, it was identified endemic goiter (83.33%). There was performed multi-profile clinical studies on young people by neurologists, neurophysicians, endocrinologists, pediatricians. Electroencephalographic study was performed by digital equipment by visual and computer analysis of the results. There were identified brain functional changes of diffuse character in EG writings. It was identified multineurological complains, especially in children with endemic goiter. With neurophysiologist's tests was estimated neurocognistic functional studies, as in people with endemic goiter also with healthy ones. According to test scores, was estimated perception of visual-space construction, speed of intellectual task performing, quality of functional recognition. According to the results, was estimated visual space memory. The scores in children with endemic goiter was lower then in healthy children. The results are giving possibility to estimate in children with endemic goiter mild neuro-endocrinology, neuro-physiology and neuro-physiology changes coursed by iodine deficiency, before infringement in their clinical appearance. In time prevention of this infringement will give us possibility to avoid future pretended infringement in intellect development.

The adaptation of TSH secretion to autonomy in non-toxic goiter may be based-on active regulation of set-point and sensitivity of central TSH-receptors, perhaps by the microRNA (MIR) gene

The hypothalamic-pituitary-thyroid (HPT) feedback system is one of the most complex regulatory systems and it has intrigued researchers for more than 50 years. One of the unsolved problems of this regulation in humans is the hypothalamic and pituitary adaption to autonomous function of the thyroid gland in non-toxic goiter (NTG). A new hypothesis, that TSH secretion is actively regulated in NTG in response to changes in thyroid autonomy in order to keep the patient euthyroid, was discussed in the present study on basis of previous experimental data in NTG patients with different degree of autonomous function. The patients were submaximally suppressed for one month with a fixed daily dose of T3. Group data suggested an inverse correlation between TSH suppression and suppression of thyroid function. Group data also suggested that TSH suppression was significantly correlated to basal TSH. This means that a NTG patient with a low normal TSH in blood before suppression (basal TSH) and a high degree of autonomous function may exhibit a relatively high TSH suppression. This ensures a minimal stimulation of the thyroid gland thereby protecting the gland from developing hyperthyroidism. A patient with a high normal TSH in blood before suppression (basal TSH) and a low degree of autonomous function, may exhibit a relatively low TSH suppression, indicating a high stimulation of the thyroid gland thereby protecting the patient from developing hypothyroidism. It is hypothesized that this adaption of TSH secretion to autonomy in NTG patients may be based on active regulation of both the set- point of the central TSH-receptors and the sensitivity of these receptors as well. Such an active regulation of the HPT axis may be controlled by one of the newly found post-transcriptional genes called MIR (microRNA).

[Current views on the etiopathogenesis of goiter in children]

The most frequent cause of goiter in children is a deficit of iodine, leading to endemia of goiter in the regions with insufficient supplementation of this element. Goiter occurs also in the course of autoimmunological diseases of the thyroid gland (Hashimoto disease, Graves' disease), genetically-related disorders of thyroid hormones, biosynthesis/impaired biosynthesis of thyroid hormones. According to the theory of goiter pathogenesis, excessive enlargement of the thyroid gland is due to adaptation of follicle cells of the gland aiming at neutralizing the impaired synthesis of the thyroid hormones caused by various intrathyroid, environmental and genetic factors/agents. The mechanisms stimulating thyrocytes to hyperplasia or hypertrophy are very complex and still unknown in spite of having identified many physiological and pathogenetic factors connected with goiter.

Development of a dried whole-blood spot thyroglobulin assay and its evaluation as an indicator of thyroid status in goitrous children receiving iodized salt

BACKGROUND

Serum thyroglobulin appears to be a sensitive marker of thyroid dysfunction in endemic goiter. However, its value as an indicator of thyroid status in children after the introduction of iodized salt has not been tested.

OBJECTIVE

The objective was to optimize and validate a thyroglobulin assay on dried whole blood spots and to evaluate thyroglobulin as an indicator of thyroid response to iodized salt.

DESIGN

A standardized, commercially available, sandwich fluoroimmunometric serum thyroglobulin assay was adapted for use on blood spots and validated in Swiss children. In a 1-y prospective study in 377 goitrous Moroccan children aged 6-15 y, the assay was used to measure thyroglobulin before and after the introduction of iodized salt. Urinary iodine, thyroid volume, thyrotropin, and thyroxine were measured, and regression was done with thyroglobulin as the dependent variable.

RESULTS

Correlation between the blood spot and serum assays was excellent (r = 0.98). The SD of the difference between the blood spot and serum assays was 3.8 micro g/L; the median CVs for the blood spot assay in controls and samples were 6.3% and 14.4%, respectively. Median thyroglobulin was 24.5 (range: 0-328.8) micro g/L at baseline and fell significantly after the introduction of iodized salt to 6.2 (0-83.1) and 4.4 (0-47.1) micro g/L at 5 and 12 mo, respectively (P < 0.0001). Regression of urinary iodine and thyroid volume on thyroglobulin was highly significant at baseline and at 5 mo (P < 0.001).

CONCLUSION

Thyroglobulin, measured in dried whole blood spots, may be a valuable indicator of improving thyroid function in children after supplementation with iodized salt.

Endothelin-1 levels in patients with disorders of the thyroid gland

The endothelium derived peptide endothelin-1 (ET-1) is the major isoform of the endothelin peptide family, which is produced and secreted in the endothelial cell system. We measured plasma levels in patients with thyroid diseases and investigated associations between laboratory and clinical markers of thyroid metabolism and ET-1 plasma levels. ET-1 plasma levels were determined in patients with Graves' disease (n = 54), endemic goiter (n = 26), patients with Hashimoto's thyroiditis (n = 21) and compared to healthy controls (n = 60). ET-1 plasma levels were significantly elevated in patients with Hashimoto's thyroiditis (p < 0.0001) and in patients with Graves' disease (p = 0.003), when compared to healthy controls. In patients with endemic goiter, no significant differences were found compared to healthy controls (p = 0.298) and when compared to patients with Graves' disease (p = 0.16). We did not observe an association between ET-1 plasma levels and parameters of thyroid disease (e.g. thyroidea-stimulating hormone, thyroxine, volume of the thyroid). Furthermore, patients with and without endocrine thyroid disease showed no significantly different ET-1 plasma levels (p = 0.78). These data suggest that the autoimmunologically induced inflammatory response of the thyroid gland in Hashimoto's thyroiditis and Graves' disease is responsible for increased ET-1 plasma levels. Furthermore, our data do not support a role for ET-1 as a valid quantitative indicator for stage or progression in endemic goiter, Graves' disease or Hashimoto's thyroiditis.

Clinically evident thyroid gland disorders in Lublin Region

The authors tried to assess the prevalence of thyroid gland pathology in Lublin and the Lublin Region population over 35 years old. The study was performed a few years after introduction of iodine prophylaxis in Poland. In our study we still found high prevalence of goitre--about 12% in town and rural population. A very low rate of diagnosed and treated patients with clinically evident thyroid gland pathology was observed in countryside area. Our data confirm the known phenomenon of considerably higher prevalence of thyroid gland diseases in females. Decrease of prevalence of hyperthyroidism in recent years but still low prevalence of overt hypothyroidism are characteristic of a temporary period from moderate iodine deficiency to sufficient iodine intake.

[Autonomic system disorders in endemic goiter]

Vegetative tonicity, reactivity and provision were studied in 88 patients with endemic goiter (EG) aged 18 to 40 years. Vegetative dystonia syndrome (VDS) in EG develops as parasympathicotonia. Subjective symptoms of vegetative dysregulation are more pronounced in high reactive and personality anxiety, in neurotism, they do not depend on extra- or introversion. VDS in EG deteriorates mental and physical performance, attention. Vegetative reactivity in EG becomes hypersympathicotonic. Vegetative dystonia affects reaction to the disease. Prolapse of heart valves often seen in EG patients results rather from hypothyroid edema of the myocardium than from VDS. Therefore, treatment of such patients with beta-adrenoblockers is not grounded. Vegetative dysregulation gradually attenuates in response to replacement hormone therapy with thyroxine.

[Natural deficiency of trace elements and ways of its prevention]

Eighty female adolescents living in the area where goiter is endemic were examined. The rates of increases in height and weight under 10 years were found to lag behind and, on the contrary, to excel their standard values in adolescence. The accelerated increases in height and weight in girls aged 11 to 15 years were attended by rises in morbidity rates. The number of children with normal sexual development in the area of goiter endemics was reduced to 28.8% and the prevalence of menstrual dysfunction increased up to 54.8%. Impaired menstrual function was most frequently recorded in girls with changed levels of follicle-stimulating and interstitial cell-stimulating hormones.

Assessment of goiter in an area of endemic iodine deficiency

Urinary iodone (UI) excretion and sonographically measured thyroid volume were investigated in 195 subjects living in 6 separate villages in the Casamance region of southeastern Senegal, West Africa. A comparison of goiter prevalence using thyroid palpation and volume measurement and of iodine excretion expressed as micrograms per gram (microg/g) creatinine or micrograms per deciliter (microg/dl) urine was undertaken, and possible pathogenetic factors were investigated. Ultrasound measured thyroid volumes were above the recommended upper limit of the reference range for an area replete in iodine in 83.1% or females, 52.3% of males, and 80.0% of children aged 13 years or younger. Overall sensitivity and specificity for palpation compared to sonographically demonstrated thyroid enlargement was 51.7% and 91.5%, respectively. Thyroid enlargement was not associated with ethnic origin, thiocyanate ingestion, HLA DR/DQ phenotype frequency, or thyroid growth-stimulating immunoglobulin (TGI) positivity. Median UI was 32 microg/g creatinine with 65.0% having values consistent with iodine deficiency (< 50 microg/g). When results were expressed as micrograms per deciliter, the percentage having values consistent with iodine deficiency (< 5.0 microg/dl) increased to 95.7%. The findings suggest a primary role for iodine deficiency in goitrogenesis in the study population. They demonstrate that classification of the severity of the endemia in this or other study populations in areas of iodine deficiency is dependent on the methods used to determine goiter prevalence (palpation or ultrasound measured thyroid enlargement), or dietary iodine status (iodine excretion expressed as micrograms per gram creatinine or micrograms per deciliter urine).

[Surgery of the goiter]

Surgery of the goiter has been greatly influenced by Theodor Kocher all over the world. Dedicated to his understanding of goiterogenesis he is considered the father of the prevention and elimination of the wide spread iodine deficiency goiter disease in Switzerland by introducing the iodinesation of salt. Therefore Switzerland is the only country in Europe, which is no longer an iodine deficiency region but remains an endemic goiter region. The traditional conservative Kocher type of surgical resection of the multinodular goiter showed to harbour the problem of a high recurrence rate. The analysis of our Bernese data (3193 thyroid operations with 4395 nerves at risk) brought us to the point to question this traditional surgical strategy. In order to lower the recurrence rate and in addition to lower surgical morbidity we started from 1990 to resect much more thyroid tissue in order to resect all pathologic thyroid tissue. This meant as a minimal surgical procedure, a thyroidectomy on one side followed by a subtotal resection on the contralateral side in case of bilateral disease. The surgical concept in parallel was supported by the novel molecular biological concept of goiterogenesis presented by our Bernese research team, which could demonstrate that the potential for goiterogenesis and clonal growth of functional and morphological independent cluster is distributed all over the whole thyroid gland. Therefore a more radical resection at the first operation will resect much more potential clones at risk to become recurrent goiters than the 'old' conservative resection type. With the more radical initial resection combined with a routine demonstration of the recurrent laryngeal nerve and the parathyroid glands we could reduce the recurrent laryngeal nerve palsy from 2.7% (nerves at risk) in the early period (1972-1990) to 0.7% with the more radical resection (1991-1996, p < 0.05). In parallel the postoperative hypoparathyroidism of the early period of 3.6% could be lowered to 1% in the actual series (p < 0.05). Theodor Kocher's conservative thyroid gland surgical concept has now one century later found a correction by a Bernese team again, which could significantly reduce the morbidity of thyroid gland surgery and as well, will greatly reduce the incidence of recurrent goiter disease after initial surgery in our endemic region.

[Endemic goiter: clinical picture and evolution]

The goiter is the most frequent clinical manifestation of the nutritional deficiency of iodine. If present in more than 5% of the general population or more than 10% of the children in school of a defined geographic area, goiter is defined endemic. Endemic goiter is an adaptive disease produced by the persistent stimulation of the thyroid gland as consequence of the thyrotropin increased secretion due to the iodine deficiency. If iodine deficiency is severe or persistent, other manifestations can be observed in the clinical picture of the iodine deficiency disorders (IDD), such as cretinism. In general goiter is not associated to other manifestations during the initial state of the disease, but nodular and toxic evolution are frequent complication of long standing disease.

Autonomy in endemic goiter

The occurrence of hyperthyroidism in many individuals after introduction of iodine prophylaxis in endemic goiter areas can have dramatic consequences for the affected individuals. It indicates that in such individuals the increase of serum thyroid hormone level in response to iodine supplementation does not exert its normal negative feedback on thyroid activity, ie, that in such individuals some thyroid tissue has become autonomous. In this short review we summarize what is known about the possible mechanisms, cause, diagnosis, and consequences of thyroid autonomy.

Effects of low level radiation from the Chernobyl accident in a population with iodine deficiency

To determine the effects of low dose radiation from 131I and 137Cs resulting from the Chernobyl disaster on the expression of endemic goiter in children, we studied children in regions with and without evidence of radiocontamination but comparable iodine insufficiency. We included 89 children in the study (radiocontaminated) region (SR) and 116 in the control region (CR) because they were either fetuses, infants, or pre-adolescents at the time of exposure. We evaluated thyroid dimensions by clinical examination and ultrasound; thyroid function by hormonal levels, and thyroglobulin measurement; histology of the thyroid by fine needle aspiration; and thyroid autoimmunity. SR subjects had 5 times the frequency of thyroid enlargement as those from CR, greatest in the younger patients. There were no instances of clinically apparent thyroid dysfunction. Antithyroid microsomal and antithyroglobulin antibodies were present in a markedly greater percentage of SR subjects. Fine needle biopsy demonstrated greater cellular proliferation in samples from SR.

CONCLUSIONS

We have demonstrated findings of autoimmune thyroid disease at markedly increased frequency in a population of children with poor iodine nutriture who were exposed to low level radiation, compared to a more iodine deficient population not so exposed. These results suggest that low level radiation may induce thyroid gland changes in children who have inadequate iodine intake nutriture and reinforce the importance of adequate dietary iodine.

[Iodine deficiency disorders]

Iodine is an important micronutrient for humans. This element is a necessary component of thyroid hormones. An insufficient dietary supply of iodine results, in the development of a variety of disorders grouped under the general heading of Iodine Deficiency Disorders (IDD), a worldwide health problem. The multifactorial nature and complex interactions of environmental conditions with host factors in the pathogenesis of endemic goiter constitutes a major challenge to the understanding and control of the problem in endemic areas. Endemic goiters constitute the most spectacular disorder from the clinical and epidemiological points of view. The control mechanism of thyroid gland, pathophysiology and epidemiology of the endemic goiter and strategies toward eradication of iodine deficiency at the end of this century, is described.

[Physiopathology of maternal and feto-neonatal thyroid in pregnant women with endemic goiter]

Endemic goitre is a socially important disease in many regions of Italy. In conditions of euthyroidism, the course of pregnancy and perinatal outcome are not burdened by significant complications. It is useful to control thyroid function and to start L-thyroxine therapy in order to avoid any further increase in thyroid size owing to the goitrogenic effect of pregnancy and to avoid transient hypothyroidism and the nodular evolution of goitre. Recent studies appear to indicate a possible physiological role for thyroid hormones in the development of the fetal CNS as early as conception, an additional motive for the administration of thyroxine in order to prevent pathologies caused by thyroid hormone deficiency in utero.

[General pathology of trace element deficiency]

According to the authors' concept, different forms of trace element deficiency show some general rules of development. All of them are followed by a decrease of immune resistance. Trace element deficiency is never isolated, it is always characterized by trace element unbalance and is followed by a considerable disturbance of metabolism (mineral, lipid, carbohydrate and protein) with relevant manifestations. Reduced immune resistance and pluriglandular endocrinopathy create the conditions for various malignancies.

Disorders of thyroid gland in India

The profile of thyroid disorders encountered in pediatric and adolescent age groups in India is similar to that seen in most parts of the world except for the prevalence of iodine deficiency disorders in certain endemic regions of this country. Clinical presentation is most commonly for hypothyroidism and goiters and infrequently for hyperthyroidism. Of nearly 800 children referred for thyroid problems, 79% had hypothyroidism (goitrous as well as nongoitrous), 19% had euthyroid goiters and 2% had hyperthyroidism. Hypothyroidism was due to thyroid dysgenesis in 75% (aplasia/hypoplasia--50% and ectopic thyroid gland 25%), thyroiditis in nearly 5% and dyshormonogenes is in 20%. The incidence of congenital hypothyroidism in our experience of screening nearly 40,000 newborns is about 1 in 2,640, which is much higher than the worldwide average of 1 in 3,800. Diagnostic delay in hypothyroidism is common and is related to lack of awareness amongst primary healthy care practitioners and family physicians as well as the cost and availability of laboratory investigations. This delay, compounded with inadequate therapeutic surveillance is responsible for the poor outcome in affected children. High incidence of dyshormonogenesis, inherited as autosomal recessive trait also calls for genetic counselling and routine sibling examination. Our results of family studies on first degree relatives of children with thyroiditis revealed presence of antimicrosomal antibodies in 43% and thyroid disease in 26%. Many etiologic factors cause goiters which may be functionally euthyroid or hypothyroid with almost equal frequency in our series. In nearly 200 schools children surveyed for goiter prevalence, 8% in high socioeconomic groups and about 21% in the low income group, had goiters. Female predominance was marked. However, iodine deficiency was not the sole cause as revealed by dietary survey and urinary iodine estimations. Hyperthyroidism is infrequent, less severe and in our experience responded well to long-term administration of antithyroid drugs. A high index of clinical awareness and education of primary health workers will help a great deal in improving the ultimate outcome in children with thyroid disorders/hypothyroidism.

Levels of thyroxine, TSH, thyroid volume and mental performance among Orang Asli in selected settlements in Malaysia

A significant difference in the levels of thyroxine (T4), thyroid stimulating hormone (TSH) and thyroid volume among settlements at various selected Orang Asli locations is reported. The levels improved according to the level of socio-economic development. No significant difference was found in mental performance by location.

[Euthyroid goiter in puberty--a harmless illness?]

An investigation was carried out in to thyroid hormones (TSH, T3, T4) and lipid parameters (total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride) in 136 adolescents (94 femals, average age 13 years). An iodine deficiency (grade II-II) with respect to the daily urine excretion per 1,73 m2 BSA was found in 75%. With few exceptions the serum levels of TSH and T4 were in the normal range. In 36% of the patients we noticed compensatory elevated T3 levels. Correlations between thyroid hormones TSH, T4, renal iodine excretion and the volume of thyroid glands were not detectable, only T3 showed a dignificant positive correlation to the thyroid gland volume. The average values of lipids in patients were found to be higher than in normals. We consider the changed lipids as a sign of a disturbed efficacy of thyroid hormones. The regional insufficient iodine supply causes goiters and to a high degree the observed hyperchole-sterolemia, too. Our results underline the necessity of a common iodine salt prophylaxis as well as the treatment of "harmless" goiters in puberty.

Thyroid function in a goitre endemia

A study was conducted to determine the thyroid function in a goitre endemia. Sadam is small village in the south district of Sikkim. Severe iodine deficiency exist in this village (prevalence of goitre 73.5%, cretinism prevalence 4%; mean urinary iodine exeretion 4.13 ng/dl - SD 3.1). Total of 72 out pf 142 households were randomly selected. All the inmates of the households above 14 years of age were examined for goitre and blood samples were collected from them for estimation of concentration of thyroid stimulating hormones (triiodothyroine T-3, thyroixe T-4) and thyroid stimulating hormone (TSH). Total of 244 subjects were examined, (137 males and 107 females). Goitre was detected in 149 (61.1%) individuals. The mean T-3, T-4 and TSH concentrations in the non-goitrous groups were (SD in parenthesis) 110.13 ng/dl (26.19), 10.12 ug/dl (2.38) and 1.01 uu/ml (0.52). The corresponding values for the goitrous group were, 132.22 ng/dl (46.25), 9.06 ug/dl (2.04) and 1.33 uu/ml (1.19). The differences in the mean concentrations between the goitrous and non-goitrous groups were statistically significant. An inverse correlation between the goitre size and T-4 on the one hand, and TSH and T-4 on the other hand was noticed. The result of the study show that functional decompensation of the thyroid occur in the majority of goitrous subjects.

[Etiopathogenesis and therapy of iodine deficiency goiter]

The main cause of endemic goiter is iodine deficiency. For the last four decades, it has been thought that the reason for goiter development is the increased action of thyreotropin (TSH) on thyroid cell proliferation. During the last years, however, it became evident that local growth factors may be more directly involved in goiter formation and, furthermore, iodinated derivatives of membrane lipids are modulators of this growth factor's actions. TSH modulates both, the growth factor and growth factor receptor expression as well as the iodine content of the thyroid gland. In addition, most of the effects of TSH on thyroid volume seems to be the induction of thyroid hypertrophy, but not hyperplasia which is related to the action of local growth factors. These new insights in the pathophysiology of goiter development are important for the regimen of endemic goiter therapy. The current concept of goiter treatment by a TSH suppressive therapy has been derived from the previous hypothesis that TSH alone is more effective in causal goiter treatment than the TSH suppressive therapy.

[Thyroid status in anemic pregnant women under conditions of endemic goiter]

Anemia is a highly prevalent condition among pregnant women in the Republic of Kazakhstan. The causes of this anemia are not quite clear, as is the problem of resistance of this type of anemia to therapy with iron preparations. The authors propose that this may be explained by the fact that many regions of the Republic are foci of endemic goiter, because tentative studies indicate a relationship between endemic goiter and hypothyrosis. The present study was aimed at examination of the thyroid status in pregnant women suffering from anemia in the town of Alma-Ata, a region endemic for goiter. Altogether 120 anemic pregnant women were examined, 60 of these with goiter and 60 without it. Control group consisted of 20 healthy pregnant women. Clinical and ultrasonic examinations, puncture biopsy of the thyroid, measurements of blood levels of TTH, total and free triiodothyronine and thyroxin, thyroxin-binding globulin, as well as of peripheral blood red cell counts, levels of hemoglobin, serum iron, assessment of total iron-binding capacity of the serum and saturation coefficient, were carried out. Healthy pregnant women from a focus of endemic goiter were found to represent a group at risk of anemia in the third pregnancy trimester. In anemic pregnant women endemic goiter aggravated anemia. Chronic iodine deficiency is conductive to formation in pregnant women of subclinical hypothyrosis whose severity increased in the presence of anemia, more so if anemia is paralleled by goiter.

[Features of adaptation of newborns born to mothers with endemic goiter]

Relationships between chronic iodine deficiency and, among other things, endemic goiter in women and adaptation of their babies in the early neonatal period were studied. A total of 125 women with endemic goiter of the Ist-IInd degrees and their newborns were examined. The diagnosis of endemic goiter was verified by the findings of an objective examination, ultrasonic examination, and puncture biopsy of the thyroid. Blood levels of triiodothyronine and thyroxin were measured in the women on days 3-4 postpartum. In the newborns Apgar score, body mass and length at birth, degree of maturity, physiologic body mass loss, duration of the icteric syndrome, time of umbilical cord drop off, and immunity status from the data of NBT test were assessed. Forty-five women without goiter and their newborns were controls. Postpartum measurements of triiodothyronine and thyroxin levels in the blood of patients with endemic goiter brought the authors to a conclusion that subclinical hypothyrosis was characteristic of them. Adaptation processes in the early neonatal period were found disordered in the newborns of mothers with endemic goiter. This manifested by a higher, vs. controls, incidence of asphyxia, hypotrophy, signs of the CNS involvement, and respiratory distress syndrome. Initial body mass recovery, disappearance of the icteric syndrome, umbilical cord loss were delayed in these newborns in comparison with the controls, and statistically reliable deviations in their immune status were revealed.

[Iodine deficiency diseases and pregnancy]

Iodine is a fundamental element of diet since it is important in thyroid hormone biosynthesis. Dietary iodine deficiency can provoke not only thyroid enlargement, but also symptoms and signs of hypothyroidism of various degree, known as "iodine deficiency disorders" (IDD). Thus, the iodine supplementation is mandatory. It can be obtained, in our regions, where subendemic deficiency is frequent, by adding iodine to salt. This is the only way to avoid anatomo-functional lesions, that are dramatic in pregnancy and childhood.

Endemic goiter in Calabria: etiopathogenesis and thyroid function

An endemic goiter study was carried out in a vast territory of the Calabria region, including the provinces of Catanzaro and Cosenza. About 50% of 7231 school-children, aged between 6 and 12 years, examined in 34 villages, presented a thyroid enlargement. The high prevalence of goiter seems to be related to a moderate iodine deficiency intake indicated by a mild urinary iodine excretion (lower than 100 micrograms/g creatinine). In a few villages, in which a two year voluntary iodine prophylaxis was carried out, an increase in the urinary iodine excretion with a decreased goiter prevalence was observed. A slight increase in TT3, FT3 and TSH in one endemic area studied, compared to the control area, was also observed. These data suggest that an effective program of iodoprophylaxis is fundamental in this region as well.

The disorders induced by iodine deficiency

This paper reviews present knowledge on the etiology, pathophysiology, complications, prevention, and therapy of the disorders induced by iodine deficiency. The recommended dietary allowances of iodine are 100 micrograms/day for adults and adolescents, 60-100 micrograms/day for children aged 1 to 10 years, and 35-40 micrograms/day in infants aged less than 1 year. When the physiological requirements of iodine are not met in a given population, a series of functional and developmental abnormalities occur including thyroid function abnormalities and, when iodine deficiency is severe, endemic goiter and cretinism, endemic mental retardation, decreased fertility rate, increased perinatal death, and infant mortality. These complications, which constitute a hindrance to the development of the affected populations, are grouped under the general heading of iodine deficiency disorders (IDD). At least one billion people are at risk of IDD. Iodine deficiency, therefore, constitutes one of the most common preventable causes of mental deficiency in the world today. Most of the affected populations live in mountainous areas in preindustrialized countries, but 50 to 100 million people are still at risk in Europe. The most important target groups to the effects of iodine deficiency from a public health point of view are pregnant mothers, fetuses, neonates, and young infants because the main complication of IDD, i.e., brain damage resulting in irreversible mental retardation, is the consequence of thyroid failure occurring during pregnancy, fetal, and early postnatal life. The main cause of endemic goiter and cretinism is an insufficient dietary supply of iodine. The additional role of naturally occurring goitrogens has been documented in the case of certain foods (milk, cassava, millet, nuts) and bacterial and chemical water pollutants. The mechanism by which the thyroid gland adapts to an insufficient iodine supply is to increase the trapping of iodide as well as the subsequent steps of the intrathyroidal metabolism of iodine leading to preferential synthesis and secretion of triiodotyronine (T3). They are triggered and maintained by increased secretion of TSH, which is ultimately responsible for the development of goiter. The acceleration of the main steps of iodine kinetics and the degree of hyperstimulation by TSH are much more marked in the pediatric age groups, including neonates, than in adults, and the development of goiter appears as an unfavorable side effect in the process of adaptation to iodine deficiency during growth. The most serious complication of iodine deficiency is endemic cretinism, a syndrome characterized by irreversible mental retardation together with either a predominant neurological syndrome or predominant hypothyroidism, or a combination of both syndromes.(ABSTRACT TRUNCATED AT 400 WORDS)

Transport of thyroid hormones to target tissues

Endemic iodine deficiency is associated with maternal hypothyroxinemia and a relatively high incidence of neurological disorders in the offspring. The previous assumption that the placenta is impermeable to maternal thyroid hormone, has resulted in the erroneous suggestion that iodine per se has an essential role in brain development. Furthermore, the observed factorial rise in thyroxine-binding globulin (TBG) in pregnancy has often been misinterpreted as preventing thyroid hormone loss to either the fetal compartment or excretory systems. However, physiochemical analysis of the role of specific binding proteins in hormone delivery, combined with epidemiological evidence and evolutionary considerations has led us to postulate that a) maternal thyroxine (T4) is transported to the fetus, and is of crucial importance in early fetal development, and b) TBG forms part of a control system specifically designed to maintain at an optimal level the T4 environment to which the developing fetus is exposed. Placental transfer of maternal T4 in a variety of mammalian species (including humans) is now well established. Further experimental studies in rats have shown that perturbation of the intrauterine thyroid hormone environment during critical phases of brain development results in a spectrum of biochemical dysgenesis. For example, in fetal brains deriving from hypothyroxinemic (Tx) rat dams, severe disruption of phosphate metabolism is observed and the ontogenesis of two enzyme activities associated with growth control, protein kinase C and ornithine decarboxylase, are compromised. Development of brain function is also impaired, as evidenced by the dysgenesis of certain neurotransmitter metabolic activities (choline acetyltransferase and DOPA decarboxylase).(ABSTRACT TRUNCATED AT 250 WORDS)

Aberrations in serum proteins and thyroid size in Nigerians on the Jos Plateau and their relation to thyrometabolic function

Controlled serum protein and thyroid function studies were carried out among 208 African patients with endemic goitre. The changes seen in the serum protein constituents were studied and evaluated in relation to thyroid hormone levels, goitre grade and the clinical state of the patient. Mean serum TBG and thyroglobulin values rose sharply in the early phase of goitre, and remained elevated throughout. Although the mean serum total T4 was statistically and significantly higher in endemic goitre compared with the normal subjects (t = 3.72. P = 0.005), the free thyroxine index was significantly lower and serum T4 fell progressively (r = 0.975) with increasing thyroid grade. In contrast, mean serum T3 rose continuously (r = 0.910) but appeared inflated due to a proportionate increase in TBG in several cases, giving a misleading picture of T3--thyrotoxicosis in otherwise clinically normal subjects. An increase in T3/T4 ratio and consequently in thyroid function, therefore occurs with advancing thyroid size. Inconsistent binding of T4 to TBG causes wide variations in thyroxine index. Mean serum albumin and betalipoprotein appeared inversely related to thyroid function. These changes imply that in order to evaluate a patient with endemic goitre accurately a detailed biochemical investigated of the thyroid may be necessary.

Growth of children in a iodine-deficient area in northern Zaïre

In a case-control study all preschool children of 50 villages in an iodine-deficient area in northern Zaïre were examined for the absence or presence of a goitre. Children with goitre but without obvious signs of cretinism (cases) were maximally matched with a goitre-free child of the same ethnic group, village, sex and age (controls). Anthropometry of cases and controls was compared in order to investigate if endemic goitre is associated with any growth impairment. Surprisingly, between ages 2 and 4 years, children with goitre are taller and heavier, and have a smaller triceps skinfold thickness. Arm circumferences did not differ between cases and controls. Stunting is more prevalent in controls. If manifest cretinism is excluded, goitre is not associated with growth retardation. The higher anthropometric figures in goitrous children remain unexplained. In the absence of any data on the hormonal status of these two groups of children, it can only be surmised that, in iodine-deficient areas, some degree of hypothyroidism negatively influencing growth might be more frequent in non-goitrous children than in goitrous ones.

Endemic goitre in Senegal--thyroid function etiological factors and treatment with oral iodized oil

Endemic goitre and its response to orally administered iodized oil has been studied in seven villages 25-30 km south of Velingara, Eastern Casamance, Senegal. In 502 adults aged greater than 15 years goitre prevalence was 62% with 18.2% having goitre grade 2 or 3. Mean free T4 (FT4) was 11.9 +/- 3.5 (SD) pmol/l and iodine deficiency was confirmed by noting median urinary I of 0.079 mumol/l (14.9 mumol I/mol creatinine) with elevated free T3 (FT3)/FT4 ratios. Serum selenium concentrations were normal. The response to 480 mg of oral iodized oil assessed at 6 and 12 months was characterized by a 35.8% increase in FT4, a 25% decrease in FT3 and a 50% decrease in TSH (all p less than 0.01) at 12 months associated with a significant decrease in goitre size measured in 70 persons when compared to 65 controls not receiving iodine. Urinary iodine rose from 0.071 mumol/l to 0.189 mumol/l (p less than 0.01) during this time and no adverse effects on thyroid antibodies (anti-thyroid peroxidase and anti-thyroglobulin) were observed. A variation in goitre prevalence between villages was noted which, in such a small geographical area, suggests that etiological factors in addition to iodine deficiency may be important in goitre pathogenesis. Oral iodized oil administration is an effective treatment for iodine deficiency goitre in the short term.

[Changes in laboratory parameters of thyroid function in children with simple goiter from the Mazovia region]

Endocrinological Out-Patients Clinic at Children's Hospital in Dziekanów Leśny takes care of the children from Mazovia region. Hormonal findings in children with simple goiter were analyzed in several groups of patients. In all those patients preferential T3-secretion and decreased T4 production was found. These findings allow to conclude, that in Mazovia region there is iodine deficiency, which is probably the main cause of goiter development.

Thyroid function in newborn infants from goitrous and non goitrous mothers

Endemic goiter is one of the health effects of iodine deficiency. Enlargement of the thyroid is often seen during pregnancy especially in the endemic iodine deficiency disorders (IDD) areas. Thyroid hormones have a vital role in the fetal development and maturation of the brain. The lack of these hormones may result in neurological damage. We measured thyroid hormones and TSH in cord blood and TSH in newborn's blood from dry blood spots on filter paper in 5-14 th days, from 58 non goitrous and 61 goitrous mothers. T4, T3 and TSH concentrations in cord blood were measured by enzymeimmunoassay (EIA) using enzymum test Boehringer and TSH from dry blood spots on filter paper were measured by radioimmunoassay (RIA). Goiter size was graded as follows: O, I, II and III. There were significant differences in cord serum T3 concentrations between non goitrous and goitrous mothers with grade I, II and III. TSH concentration in newborn's blood from goitrous mothers of grade III were significantly higher than those from non goitrous mothers and from goitrous mothers of grade I. T4 concentration in cord blood from non goitrous mothers in IDD area was significantly lower than those from non IDD area and those from goitrous mothers in the IDD area. There were significant differences also between TSH concentration in newborn's blood spots from goitrous mothers in IDD area and those from goitrous mothers in non IDD area and from non goitrous mothers in IDD area. Two cases of congenital hypothyroidism were found in infants from goitrous mothers.(ABSTRACT TRUNCATED AT 250 WORDS)

Unaltered pulsatile and circadian TSH release in euthyroid patients with endemic goitre

To evaluate the pathophysiological role of TSH in goitrogenesis we investigated pulsatile TSH secretion in 11 patients with a non-toxic goitre and in 11 healthy controls. Thyroid volume was 40 +/- 10 ml in the goitre group and 15 +/- 4 ml in the controls as measured by ultrasound. Blood was sampled continuously via an indwelling venous catheter at 10-min intervals over 24 h. Neither the mean 24-h serum TSH levels (goitre 1.1 +/- 0.5 vs controls 0.9 +/- 0.4 mU/l) nor the nocturnal surge of TSH were significantly different between the two groups. The average of the TSH pulse frequency (goitre 10.8 +/- 3.7 vs controls 9.6 +/- 3.5 pulses/24-h) and of the TSH pulse amplitude (goitre 0.4 +/- 0.2 vs controls 0.3 +/- 0.1 mU TSH/l) as analysed by DESADE programme (detection of secretory activity by discrete deconvolution) did not differ in the two groups. Furthermore, there was no correlation between the volume of the thyroid gland and the dynamics of the TSH secretion. We conclude that our data do not suggest a relevant pathophysiological role of TSH secretion in the development of non-toxic goitre in man.

[Audiological and neuropsychological development study in a sample of school children from a low-iodine area of the Central Apennines that is endemic for cretinism]

We have evaluated neuropsychic development in 70 normal schoolchildren in an area of severe endemic goitre and cretinism in the Central Apennines (Montefeltro). In each subject we have studied auxological, psychometric and audiometric parameters, together with tympanograms and stapedial reflexograms. Auxological data were in the normal range, as were the stapedial reflexograms and tympanograms. On the contrary, 54.8% of the sample performed below the 25th percentile in psychometric tests (Raven test PM-47), being also 22.8% below the 5th percentile. Audiometric data showed a neurological hearing impairment in 3.1% of the children tested, as compared with 0.28% in the area of Pisa. These data point out that an impairment of central nervous system function still persists in this area of severe endemic goitre.

Endemic goitre and iodine deficiency disorders--aetiology, epidemiology and treatment

Disorders caused by iodine deficiency continue to be a major health problem in many underdeveloped areas of the world. The most significant is the impaired mental and physical development which occurs as a result of iodine deprivation early in life. Individuals in affected communities show a spectrum of abnormalities which can be attributed to two interacting pathological processes. Fetal hypothyroidism in the first and early second trimester predominantly affects the developing nervous system causing deaf-mutism and mental retardation. If hypothyroidism occurs in the early postnatal period the main abnormalities are growth stunting and related somatic abnormalities. Subclinical deficits of intellectual and motor development may also be found in apparently normal individuals living in affected areas. Although dietary iodine deficiency is clearly the major aetiological factor in both endemic goitre and cretinism, cofactors such as goitrogens, other trace element deficiencies and immunological mechanisms may greatly modify the expression of these disorders. Iodine supplementation programmes form the basis of the public health strategy in combatting these disorders. Where the iodization of foodstuffs is not feasible, an alternative is the use of iodine containing oil which can be given orally or intramuscularly to provide a long-lasting supply of iodine.

Thyroid function of subjects with goitre and cretinism in an endemic goitre area of rural China after use of iodized salt

Endemic goitre and cretinism are still a public health problem in China. An epidemiological survey showed that about 5% of the inhabitants in Daxin village, Henan province, had goitre or cretinism after an iodized salt prevention programme had been carried out for two decades. The main food for the inhabitants of this area has an iodine content less than 30 nmol/kg and the water for cooking and drinking has an iodine concentration between 7-12 nmol/l. We studied thyroid function in subjects of this village. There were 42 with grade 0 goitre (males 29, females 13), 42 grade I (males 23, females 19), 27 grade II (males 9, females 18), 31 grade III (males 14, females 17) and 34 cretinism patients (males 30, females 4) diagnosed and classified according to WHO criteria. Serum T4, free T4, T3, free T3, T3 uptake, TSH and thyroglobulin were measured in these subjects. The patients with goitre or cretinism had significantly decreased serum free T4 and increased serum T3 and free T3 levels compared with those of controls. Thyroid size was positively correlated with age and serum thyroglobulin concentrations. Serum thyroglobulin was significantly increased even in the grade 0 goitre subjects. The percentages of subjects with serum free T4 less than 12 nmol/l, T3 greater than 2.5 nmol/l, free T3 greater than 5.2 pmol/l, TSH greater than 3.5 mU/l, T3/T4 ratio greater than 0.03 and free T3/free T4 ratio greater than 0.36 were significantly higher among goitre and cretinism patients than among controls. The data suggest that there is partial compensation for a marginal deficiency of iodine in the inhabitants of this village.