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Biomedical subjects

N Etling

Publications and source records attributed to N Etling.

14 recordsLinked to original sources
PubMed1987

[Thyroid hormones in rats receiving increasing doses of lithium].

Thyroid hormones were determined in rat serum, thyroid, liver and kidney tissues; the animals were fed for 40 days an equilibrate diet and various amounts of lithium carbonate were added to drinks. Serum lithium levels were related to their absorption. There was no change in rats drinking 300 mg Li2CO3/l solution for 5 weeks or 600 mg/l for 2 weeks, when compared to control rats. But 600 mg/l solutions for 5 weeks led to hormone increase in thyroid tissue. With 1200 mg/l acute hormonal decrease was seen in serum (thyroxine, T4: 3.2 micrograms/dl and control: 4, triiodothyronine T3: 54.8 ng/dl and control: 64) in liver tissue T3: 2.6 ng/g and control: 3.5), and in kidney tissue (T3: 4.8 ng/g and control: 6.4). In some animals receiving 600 or 1200 mg, lithium concentration was very high, body weights were very much reduced and there was large hormonal decrease in serum (T4: 1.4 micrograms/dl, T3: 48.5 ng/dl) in liver tissue (T4: 10.5 ng/g and control: 20.7; T3: 2.1 ng/g) and in kidney tissue (T4: 6.9 ng/g and control: 13.5 and T3: 3.3 ng/g). Hormonal changes were parallel to tubular kidney damage. These results are similar to those described in patients receiving lithium treatment.

Animals↗
PubMed1986

First-month variations in total iodine content of human breast milks.

In 183 samples of breast milk from 23 young mothers we found the mean total iodine content to be 47 ng/ml, a value that is not dependent on length of gestation. There is a progressive increase in iodine concentration from colostrum to transitional and mature milk. The results show that breast milk sometimes contains an amount of iodine barely necessary to make thyroid hormones, which is around 10 micrograms in the first days of life rising to about 15-20 micrograms after four weeks. Secondly, nursing mothers should be watched, because if their daily breast milk contains more than 50 micrograms iodine for several consecutive days, they may be on a negative balance.

Adult↗
PubMed1986

[Effect of dietary supply of calcium on thyroid function in rats].

To determine if calcium had a goitrogenic effect on the thyroid function in rats, weanling rats were fed, for three weeks, a diet containing either 0.5 microgram or 0.04 microgram iodine per gram of diet, or an adequate (0.47%) or an excessive (2%) amount of calcium. With an adequate iodine diet, the calcium load did not induce an increase in the weight of the thyroid or a decrease in serum thyroid hormone concentration. However, the rats given a calcium load had a lighter body weight and a lower iodine content in the thyroid tissue; they also had a higher thyroxine (T4) content in the liver and kidney tissues than the rats receiving an adequate calcium diet. With a low iodine diet, the calcium load brought out a decrease in growth and a lower serum triiodothyronine (T3) concentration and liver and kidney T3 contents. These changes suggest that the calcium load might have acted on the thyroid function through an inhibition of T4-T3 conversion in the serum as well as in liver and kidney tissues.

Animals↗
PubMed1979

[Iodine overloads in amniotic fluids (author's transl)].

The mean of total iodine levels in amniotic fluid samples is 7.8 ng/ml during the middle of pregnancy and 4.4 ng at the end. On about 200 samples collected at random from high risk pregnant women, 14% fluid contain iodine load. This iodine excess comes from water-soluble iodinated drugs administrated to the pregnant women; most are less than 300 ng/ml but 24 hours after urography the load reaches 80,000 times the mean value. Biochemical analyses have shown the iodine excess was iodide, easely released. In our study no neonatal hypothyroidism was noticed probably because that degradation. However administration of any iodinated drug to pregnant women may be a risk to the fetus.

Amniotic Fluid↗
PubMed1979

The iodine content of amniotic fluid and placental transfer of iodinated drugs.

Determinations of total iodine content, levels of thyroxine (T4) and triiodothyronine (T3), and protein concentrations were made on amniotic fluid. A total of 218 samples obtained at various stages of pregnancy, from both normal and pathological pregnancies, were studied. Normal values for the iodine and hormone concentrations are presented. Several amniotic fluid samples showed greatly elevated iodine levels, thought to be the result of maternal iodine intake. This study demonstrated that such elevated levels can be produced by urography with an iodinated medium, by thyroid extract therapy, and by vaginal therapy with an iodinated agent. Levels of T4 and T3 in amniotic fluid decreased slightly from the second to the third trimester and were unrelated to the total iodine levels. Despite reports in the literature of fetal hypothyroidism produced by amniography with a fat-soluble medium, no thyroid defect was observed in this series in the presence of elevated amniotic fluid iodine levels or when a water-soluble iodinated medium was used for amniography.

Amniotic Fluid↗
PubMed1978

[Levels of triiodothyronine and reverse triiodothyronine in the thyroid glands of man and swine at different stages of development].

3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine (rT3) were measured by radioimmunoassay in saline extracts of neonates and human adult thyroid tissues and of fetuses, Piglets and adult Swine thyroid tissues. In all these extracts, T3 content was higher than rT3 content whatever the period of development. Both triiodoamino acids represent a small percentage of the iodinated protein in thyroid tissues.

Adult↗
PubMed1978

[Fetal and neonatal triiodothyronine (author's transl)].

Thyroid hormones of amniotic fluids give informations about their presence in the fetus. T3 and T4, determined by radioimmunoassay, are found as soon as 12 weeks of gestation. Their amounts are higher at 17 weeks than at 30-40 weeks of gestation. Thyroid tissues of premature and full term neonates were analysed by chromatography after hydrolysis and 127I determined. T3 amount was very low near birth and increased with duration of survival. These results may be related to hormonal serum changes observed in the early neonatal period.

Amniotic Fluid↗
PubMed1977

Concentration of thyroglobulin, iodine contents of thyroglobulin and of iodoaminoacids in human neonates thyroid glands.

The iodine and protein concentrations, the iodoamino acids content of thyroglobulin (TG) were determined in 17 thyroid tissues from human neonates who died from 3 hours to 47 days after birth. Total iodine concentration of neonate tissues increased with life duration. TG concentration was related to the survival duration of the neonates. Increase of the iodine content was associated to the increase of the TG content: mean value was 0.16 mug 127I/100 mug TG in neonates who died within the first 20 hours after birth, 0.25 mug in neonates who survived 26 to 72 hours and 0.43 mug in neonates living more than 10 days. Expressed as iodine content to total iodine ratio, iodoamino acid percentages were not related to the tissue. When the iodoamino acids were expressed in residues per molecule of TG, iodtyrosines, thyroxine and triiodothyronine increased with duration of survival. These variations in iodine content and concentration of thyroglobulin could be related to acute hormonal changes in serum observed in early neonatal period.

Humans↗
PubMed1977

Iodoprotein and iodoamino acid distribution in pig thyroid tissues at different periods of development.

A biochemical study of the thyroid tissue in pigs at various stages of development was undertaken. The iodine and protein concentrations, and the iodoamino acid content of thyroglobulin (TG) were determined. Expressed as mu 127I/100 mg wet tissue, the mean iodine content of pig fetus is 66.4, 89.2 in the piglet and 168 in the adult pig. TG accounts for 95% of total proteins; its content increases with age. Mean iodine content of TG is 0.70 mug 127I/100 microgram in the fetus, 0.78 in the piglet and 0.97 in the adult pig. The average number of molecules of thyroxine residues is 1.6 in the fetus, 2.2 in the piglet and 3.5 in the adult. Average triiodothyronine residues are lower around birth than in the adult. At all stages of development, synthesis of thyroxine is less effective in the pig than in the human, relative to the iodine content of TG. In contrast to the human, iodinated compounds are not found at a very low level near birth, but TG and iodine content regularly increase.

Age Factors↗
PubMed1975

Histological and biochemical changes in neonatal thyroid tissues.

The thyroid tissues of 17 infants who died between 3 hours and 46 days after birth were studied by histological and biochemical techniques. The morphological aspect and the iodine content of these tissues are not related to the gestational age of the neonates, but they are related to the survival time. There are dramatic events early after birth: desquamation of the epithelium and absence of colloid, low iodine content of tissue extract (less than 1 mu g 127I per mg of protein) and low percentage of thryoglobulin (less than 10%). 24 hours after birth, the vesicles fill with colloid and the epithelium is cuboidal; the iodine content of the protein increases (between 1 and 2 mu g 127I per mg protein) as well as the thyroglobulin percentate (around 20%). One week after birth, there is a maximum of colloid and flat epithelium; the iodine content of the protein extract is much higher (more than 2 mu g 127I per mg protein) as is thyroglobulin percentage (up to 40%). Our studies of thyroid tissues of neonates suggest that a leakage of colloid, iodine and thyroglobulin takes place in the perinatal period, this phenomenon being followed by their rapid repletion.

Age Factors↗