Type II iodothyronine 5'-deiodinase and uncoupling protein in brown adipose tissue of human newborns.

Brown adipose tissue (BAT) is the major thermogenic organ of the human neonate. To determine whether it is also active in the peripheral conversion of T4 to T3, as shown in several animal species, interscapular BAT from 13 newborns of 25-40 weeks gestational age who survived 4 days, at most, was investigated. BAT was found to contain significant amounts of the mitochondrial uncoupling protein (UCP), the rate-limiting component of heat production. The specific content of UCP increased from 29.4 +/- 3.3 to 62.5 +/- 10.2 pmol/mg protein between 25 and 40 weeks of gestation, respectively, and the UCP/F1-ATPase molar ratio, a sensitive marker of brown fat differentiation, increased similarly. BAT was also found to contain iodothyronine 5'-deiodinase (5'D), which appears to be a type II enzyme, based on high affinity for T4 (Km, 2.9 nmol/L) and insensitivity to propylthiouracil (10% inhibition by 1 nmol/L). 5'D was active by 25 weeks gestation, and the specific activity increased from 116 +/- 15 to 417 +/- 46 fmol/h.mg protein during the period examined. The development of 5'D activity was similar to the changes in UCP content; both exhibited a major increase before 32 weeks gestation. The results indicate that thermogenic function and 5'D activity develop in human BAT rather early, during the first half of the last trimester of gestation. The activities of 5'D in human BAT are comparable with 5'D activities found in animal BAT stimulated during the perinatal period, by cold exposure, or by increased cAMP levels.

[Practical results of monitoring pregnancy in women with systemic lupus erythematosus]. / Praktické výsledky sledování tehotenství u zen se systémovým lupus erythematodes.

BACKGROUND: The authors dealt with the urgent problem under what conditions it is possible to achieve in a woman with systemic lupus erythematosus (SLE) or another collagenosis, or secondary antiphospholipid syndrome (APS) a favourable outcome of pregnancy and the delivery of a healthy infant. METHODS AND RESULTS: The investigation comprised 23 women incl. 20 with SLE, two with the mixed form of a diffuse connective tissue disease (MCTD) and one with Sjögren's syndrome of the primary type. From the total number of 20 pregnancies six were consulted in advance with a doctor (group I-s-called planned pregnancies) and all terminated by a successful delivery. Of 11 pregnancies which were not consulted with a doctor in advance (group II-so-called unplanned pregnancies) 9 were terminated in term, however, only 5 with a successful delivery (55.5%), two women are still pregnant. Exacerbation of the basic disease during pregnancy was recorded only once and did not lead to discontinuation of the pregnancy. CONCLUSIONS: The authors provide evidence that desired pregnancy of informed women suffering from SLE or another collagenosis when assisted by a specialized medical team can lead to a successful delivery of an infant.

[Fatty acids in the serum of hypotrophic neonates]. / Mastné kyseliny v séru hypotrofických novorozencu.

Using gas chromatography, Carlo Erba 2531 measurements were performed and the composition of serum fatty acids in 9 hypotrophic human newborns (the mean birth = 2184 g, the mean gestation age = 39 weeks) was evaluated. Fatty acids were detected as methylesters and their levels were compared with fatty acids levels of control healthy neonates born at term (n = 32). In the hypotrophic newborns the content of saturated fatty acids (short and medium-chain in particular) significantly increased, the total amount of polyunsaturated fatty acids (PUFA) series n-3 and n-6 significantly decreased and the proportion of arachidonic acid remained unchanged in comparison with the control group.

Lipolytic effect of TSH, glucagon and hydrocortisone on the adipose tissue of newborns and adults in vitro.

In an in vitro study, TSH stimulated glycerol release from the subcutaneous adipose tissue of newborns, but had no effect on its release from the adipose tissue of adults. Hydrocortisone stimulated only NEFA release in newborns. Glucagone had no effect on either neonatal or adult adipose tissue.

Effect of human chorionic gonadotropin on blood free fatty acids, glucose and on the release of free fatty acids from subcutaneous adipose tissue in various groups of newborn and adults.

After administration of human chorionic gonadotropin (HCG; 500 IU/kg intramuscularly), the blood concentration of free fatty acids increases within 30 min in 1-day-old full-term, premature and small-for-data newborns. This effect does not appear in 1-day-old newborns of diabetic mothers with insulin-dependent diabetes, in 7-day-old newborns nor in adults. Glucose concentration rises in all groups of newborns, and no effect is observed in adults. In the in vitro study, HCG increases lipolysis in newborns' adipose tissue. This effect was not observed in adults.

Activity of some enzymes of carbohydrate metabolism in human subcutaneous adipose tissue in newborns, infants and adults. I. Activity of pyruvate kinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase.

The activity of glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, pyruvate kinase (PK) and lactate dehydrogenase (LDH) was measured in human adipose tissue (AT) of newborns aged 0-2 and 2-48 h, of 3- to 5-month-old infants and of adults. AT was sampled by means of a special needle from the gluteal region without anesthesia. We observed significantly higher activity of the two pentose phosphate shunt enzymes when calculated on protein content and wet weight basis in newborns as compared to infants and adults. There were no differences for PK and LDH between newborns and adults when the values were calculated for the soluble protein. The protein concentration of the AT decreased significantly during the development.

[Serum fatty acids in premature neonates]. / Mastné kyseliny v séru predcasne narozených novorozencu.

In the past we have published several papers concerning the evolution of large spectrum of fatty acids in the brain or in the blood-serum in rats or in human newborns (and their mothers just after the delivery). Therefore we realized this study: the blood-serum spectrum of fatty acids in the healthy human newborns (n = 32) was compared with the spectrum of fatty acids detected in the blood-serum of human premature neonates (n = 22). The birth-weight in the control group was 3,882, in the premature neonates 2,137 g only. Fatty acids were measured as methylesters (FAME) using the method of gas chromatography and absolutely the same methodological approach as in our previous studies (33, 22, 23). The results were computed by biocybernet. dep. of Physiological institute and the statistics were evaluated by Mann-Whitney U test. It was established that the premature neonates show a distinct greater content (expressed in percentage) of saturated fatty acids and a smaller share of polyenoic FA (PUFA). A further marked difference consists in a significant lower of the n-3 FA and consequently a higher n-6/n-3 index. In premature neonates a significant increase of caprylic acid and arachidonic acid in the blood-serum was detected. The significance of described changes in the participation of single fatty acids in the premature neonates for their maturation, structural evolution especially of the brain cells and for therapy, is discussed.

Fatty acid values in the plasma of neonates, umbilical cord and maternal blood.

The proportion of a wide range of fatty acids was studied in the plasma of 15 healthy newborn infants following a physiological pregnancy and delivery. The same measurements were done in seven healthy mothers (immediately after parturition) and the proportion of fatty acids was analysed in mixed umbilical cord blood (n = 7). The fatty acids were identified by gas chromatography as their methyl esters (FAME). In newborn infants the proportion of saturated fatty acids was found to be 42.3%, of monoene fatty acids 31.3% and of polyene fatty acids 25.4%; type n-6 fatty acids formed 13.9% and n-3 11.1%. The proportion of the various fatty acids in healthy maternal plasma was 37.9% (saturated), 34.4% (monoene) and 25.0% (polyene) respectively; type n-6 fatty acids formed 21.6% and type n-3 only 3.6%. The values in mixed cord blood were 44% (saturated FA), 34.8% (monoene FA) and 20% (polyene FA); group n-6 FA accounted for 17.4% and n-3 for only 2.1%. In the above three series we also described the sequence of the fatty acids present in the largest amounts. This is part of an extensive study, in a large series, of the commonest perinatal risks. We particularly draw attention to the high proportion of long-chain fatty acids (C 22 - C 26) in the plasma of healthy newborn infants.