Maternal serum screening for Down syndrome: a survey of pregnant women's views.

OBJECTIVES: This study was undertaken to assess women's self-reported awareness of Down syndrome before they became pregnant and after they were supposedly informed about screening. We investigated their understanding of the purpose of screening and what a high statistical risk for Down syndrome means, and if there was a high statistical risk whether they would undergo amniocentesis. METHODS: Pregnant women (n=274) ranging from 17 to 43 years of age, with different educational backgrounds, were surveyed by means of a questionnaire which was given to them immediately before blood samples were taken. RESULTS: Women without a college education were significantly less likely then those with a college education to be aware of Down syndrome prior to pregnancy. Many of them reported being unaware of it even after they had been counseled and tested. Women with a lower level of education were also significantly less likely to have a clear understanding of purpose of screening. Fewer than 0.7% of women who were tested said they were not prepared to undergo amniocentesis, and 47.1% said they would consider amniocentesis only after receiving the screening test result. CONCLUSION: Procedures for education women prior to maternal screening must be provided.

Screening for Down's syndrome and neural tube defect in Croatia. A regional prospective study.

OBJECTIVE: The purpose of this study was to investigate the efficiency of second-trimester maternal serum screening for Down's syndrome and open neural tube defects using alpha-fetoprotein and free beta-human chorionic gonadotropin as serum markers. METHODS: 3, 188 women underwent testing between 14th and 22nd week of pregnancy. Of all tested patients, 25.4% were >/=35 years old. A cut-off risk of >/=1:250 for Down's syndrome and MS-AFP >/=2.0 MoM for open neural tube defect were considered screen-positive. RESULTS: The detection rate for Down's syndrome was 77.8% (7/9) with 8.2% screen-positive rate (7.9% false-positive rate). When evaluated separately, in patients younger than 35 and in those >/=35 years old, the screen-positive rates were 3.1 and 23.3%, respectively. A total of 52 (1.6%) were found screen-positive for open neural tube defect; 2 cases of encephalocela and 1 case of gastroschisis were confirmed prenatally. CONCLUSION: The respectable number of cases with trisomy 21 identified in this study confirms that routine mid-trimester screening for Down's syndrome including MS-AFP, free beta-hCG and maternal age is useful in identifying pregnancies at increased risk.

Exogenous and endogenous suppression of thyroid-stimulating hormone induces similar effects on thyroidal iodothyronines.

Thyroidal concentrations of T4 and T3 and the T4/T3 ratio were analyzed in the nodular and paranodular tissues from two groups of patients with suppressed TSH secretion. The first group consisted of 17 patients with nontoxic nodular goitre (NG), 8 of whom received long-term levothyroxine therapy to suppress TSH, while remaining 9 were untreated. The second group consisted of 10 patients with autonomously functioning thyroid adenoma (AFTA), in whom TSH secretion was suppressed due to the adenoma-induced increase in thyroid hormone concentrations. In nodular tissues of NG patients, thyroidal T4 and the T4/T3 ratio were significantly higher in treated than in untreated patients (0.34 +/- 0.05 vs. 0.15 +/- 0.02 mol T4/mol of thyroglobulin (Tg) and 10.9 +/- 1.2 vs. 5.2 +/- 0.7 respectively). Analysis of paranodular tissues of NG patients also revealed a higher T4/T3 ratio in treated patients (16.0 +/- 2.1 vs. 6.9 +/- 0.9), although thyroidal T3 and T4 concentrations in treated and untreated patients were similar. In AFTA patients, both T3 and T4 concentrations were higher in the adenoma than in paranodular tissues (0.14 +/- 0.04 vs. 0.02 +/- 0.005 mol T3/mol Tg and 1.08 +/- 0.32 vs. 0.26 +/- 0.06 mol T4/mol Tg), whereas the T4/T3 ratio was significantly higher in paranodular tissues (23.2 +/- 5.9 vs. 9.3 +/- 1.8). These results indicate that suppression of TSH induced either exogenously or endogenously results in an increase in the thyroidal T4/T3 ratio that reflects an increase in T4 and/or a decrease in T3 concentrations. These findings also support the notion that TSH preferentially stimulates thyroidal T3 production.

Relationship between T4, T3 and T4/T3 ratio in thyroid tissue, thyroid and peripheral veins in patients with nontoxic nodular goiter.

The relationship between T4, T3 and T4/T3 ratio in thyroid nodules/paranodular tissues, thyroid and peripheral veins has been investigated in 26 patients with nontoxic nodular goiters; eleven of them were treated with l-thyroxine 150 micrograms daily. A significant correlation between iodothyronine concentrations and T4/T3 [corrected] ratio in paranodular thyroid tissues and thyroid effluents was found in both groups of patients. By contrast, the correlation between these parameters in the nodule and thyroid veins was poor, which implies that the thyroid hormone pattern in the thyroid veins on the side of nodular lesion is predominantly controlled by the release of the hormones from paranodular healthy tissue. A close dependence of the serum T4/T3 ratio on the values of iodothyronines and their ratio in thyroid tissues and thyroid veins was observed in nontreated, but not in treated patients. Conversely, in the latter group, the thyroidal T4/T3 ratio in paranodular tissue, but not in the nodule, was found to be dependent on the serum T4/T3 ratio, suggesting that paranodular thyroid tissue more readily responds to 1-thyroxine-inhibited TSH secretion. The results demonstrate that 1. the serum thyroid hormone pattern under physiological conditions is dependent on the intrathyroidal T4/T3 ratio, and 2. minor alterations in the serum thyroid hormones may secondarily change the thyroidal T4/T3 ratio, presumably by their effect on TSH secretion.

Daily iodine intake in healthy children and adults and in goitrous patients in nonendemic Yugoslav area.

Daily iodine intake has been investigated in 52 healthy children (5-14 years), 112 healthy adults and in 39 patients with nontoxic goiter from the area of Zagreb/Yugoslavia. Fourteen goitrous patients received 1-thyroxine 150 micrograms daily for at least three months before the examination. Iodine intake has been estimated on the basis of urinary iodine excretion (microgram I-/g creatinine) in the first morning specimen. Iodine excretion in nontreated goitrous patients (92 +/- 30; Mean +/- SD) was significantly lower than in healthy adults (112 +/- 38), while the value in treated goitrous patients (165 +/- 69) was significantly higher than that in nontreated goitrous and healthy adult subjects. The results suggest that Zagreb area, although classified as nonendemic, has borderline iodine intake, and that relative iodine deficiency is of importance in goiter formation. The authors plead for increased daily iodine intake through increased table salt iodisation from actual amount of 10 to 20 to 25 mg KI/kg salt in order to provide an average daily intake of 250 micrograms of iodine.

Similar concentrations of thyroidal iodothyronines and T3/T4 ratio in normal thyroids from two Yugoslav districts with different iodine intake.

In spite of different daily iodine intake in two yugoslav districts (littoral-Split 297 +/- 76 (Mean +/- SD) and continental-Zagreb 111 +/- 36 micrograms/g creatinine, p less than 0.001), thyroidal iodothyronine concentrations and T4/T3 ratio in normal post mortem thyroids were comparable. T4 was 260.0 +/- 42.6 micrograms/g w.w. (Mean +/- SE) in Split group vrs. 279.9 +/- 59.4 in Zagreb. T3 was 12.8-2.0 vrs. 12.8 +/- 2.2 and T4/T3 ratio 21.6 +/- 1.9 vrs. 21.1 +/- 2.9 in Split and Zagreb, respectively. It has been concluded that relatively small difference in iodine intake has no effect on thyroidal concentrations of iodothyronines and T4/T3 ratio.

The urinary iodide excretion in subjects on different diets.

The urinary iodide excretion in hospital subjects on regular and different restrictive diets was investigated. In subjects on a regular diet the average urinary iodide (microgram I-/g creatinine; mean +/- SD) was 104.7 +/- 36.7. In subjects on a low caloric diet the urinary iodide content was 101.1 +/- 24.2; in subjects starving for weight-reduction the mean value was 63.2 +/- 23.9, significantly different from the controls (p less than 0.005). In subjects on a high-caloric diet the urinary iodide was 145 +/- 45.4, in those on a hepatoprotective diet 96.8 +/- 18.8, respectively. The iodide excretion in subjects on an ulcer-protective diet was on the average 76.4 +/- 22.3 which was significantly different from those on a regular diet (p less than 0.01).

Increased thyroidal T4/T3 ratio in nodular and paranodular tissues of nontoxic goiter following suppressive treatment with thyroid hormones.

The effect of suppressive treatment with thyroid hormones on thyroidal iodothyronines and T4/T3 ratio in nodular and paranodular tissues was investigated in 12 patients with nontoxic goiter. Results were compared to those from 11 nontreated patients. Continuous thyroid hormone administration produced a significant increase in thyroidal T4 and T4/T3 ratio in nodular tissues while T3 remained unchanged. In paranodular tissues a significant rise of T4/T3 ratio, an insignificant increase in T4 and a decrease in T3 were observed following the administration of thyroid hormones. The results are very similar to those obtained in paranodular tissue of autonomously functioning thyroid nodule, and are probably the consequence of suppressed TSH secretion, as TSH predominantly stimulates the synthesis of T3 and/or thyroidal T4 monodeiodination.

Thyroidal thyroxine and triiodothyronine in autonomously functioning thyroid nodule and paranodular tissue.

Thyroidal thyroxine (T4), triiodothyronine (T3), thyroglobulin (Tg) and T4/T3 ratio were investigated in nodular and paranodular tissue from 16 patients with autonomously functioning thyroid adenomas. The concentration of T4 and T3 in the nodule were 97.7 +/- 20.5 (Mean +/- SE) and 10.2 +/- 2.4 micrograms/g wet weight (w.w.). Both iodothyronines were significantly lower in paranodular tissue (22.6 +/- 4.8 and 1.45 +/- 0.32 micrograms/g w.w., respectively), but with disproportionately decreased T3 which resulted in T4/T3 ratio (25.4 +/- 6.4) higher than in adenoma tissue (11.2 +/- 1.6). In patients with high normal or supranormal serum T3 concentration, thyroidal concentration of T3 in adenoma tissue was higher (15.6 +/- 5.0 vs. 6.3 +/- 1.2 micrograms/g w.w.) and T4/T3 ratio lower (8.05 +/- 2.1 vs. 13.2 +/- 1.9) than in patients with normal serum T3. The results suggest that thyroid release of T3 from adenoma is relatively higher than T4 in patients with autonomously functioning thyroid nodules and increased peripheral T3.

Low thyroidal T3 in nodular goitrous tissue.

Six nodular tissues of non-treated and four of treated patients (suppressive treatment with thyroid hormones from three months to two years until the operation) with nodular non-toxic goitre contained low T3 (less than 1 ug/g w.w.). The results of iodothyronines and thyroglobulin (Tg) were compared with respective tissues containing T3 greater than 1 ug/g w.w. In non-treated patients, nodular tissues with low T3 and very high T4/T3 ratio showed T4 and Tg concentrations not different from the tissues with T3 greater than 1 ug/g w.w. In the goitres with low T3 of treated patients, T4 was also reduced but disproportionately to T3. Microscopically, nodular goitres with low T3 were characterized with gross fibrous infiltration and diffuse haemorrhage which was substantially different from histological findings in nodular goitres with T3 greater than 1 ug/g w.w. High T4/T3 ratio in the tissues with low T3 is similar to increased T4/T3 ratio in paranodular tissues of autonomously functioning adenomas. The results suggest that low T3 and high T4/T3 ratio in nodular goitrous tissue could be due to grossly impaired thyroid function or due to suppressed secretion of TSH.

Serum thyroid hormones in two Yugoslav districts with different iodine intake.

Serum thyroid hormones were measured in two areas of Yugoslavia, one with relatively low iodine intake, Zagreb (urinary iodide 111 +/- 36 microgram/g creatinine), and the island of Brac with higher iodine intake (247 +/- 76 microgram/g creatinine). The serum concentration of T4 and T3 in two groups were not different. These data confirm previous findings that iodine intake within accepted normal range, is not a factor in determining serum thyroid hormone levels.

Conversion of thyroxine to triiodothyronine and reverse triiodothyronine in human placenta and fetal membranes.

Conversion of thyroxine (T4) to 3,5,3'-triiodothyronine (T3) and reverse 3,3',5'-triiodothyronine (rT3) was measured in vitro in human placenta and fetal membranes. T4 (5 micrograms/ml) was incubated in 0.15 mol/l phosphate buffer with tissue homogenates for 2 h at 37 degrees C, and the T3 and rT3 generated were determined in ethanol extract using RIA methods. The placenta and chorion homogenates converted more T4 to T3 than to rT3; the placenta was more active than the chorion. In both tissues the highest converting activity was found in microsomal fractions.