Leptin concentrations in maternal serum and amniotic fluid during the second trimenon: differential relation to fetal gender and maternal morphometry.

Leptin, a hormone produced by adipocytes, provides information on the availability of fat stores to the hypothalamus and acts as an afferent satiety signal regulating appetite and energy expenditure in both rodents and humans [Zhang Y, Proenca R, Maffei M, Barone M, Leopold L, Friedman JM. Positional cloning of the mouse obese gene and its human homologue. Nature 1994;372:425-432; Sinha MK. Human leptin: the hormone of adipose tissue. Eur J Endocrinol 1997;136:461-4; Campfield LA, Smith FJ, Guisez Y, Devos R, Burn P. Recombinant mouse ob protein: evidence for a peripheral signal linking adiposity and central neural networks. Science 1995;269:546-9; Halaas JL, Gajiwala KS, Maffei M, Cohen SL, Chait BT, Rabinowitz D, Lallone RL, Burley SK, Friedman JM. Weight-reducing effects of the plasma protein encoded by the obese gene. Science 1995;269:543-6; Saladin R, De Vos P, Guerre-Millo M, Leturque A, Girard J, Staels B, Auwern J. Transient increase in obese gene expression after food intake or insulin administration. Nature 1995;377:527-9; Campfield LA, Smith FJ, Burn P. The OB protein (leptin) pathway - a link between adipose tissue mass and central neural networks. Horm Metab Res 1996;28:619-632; Blum WF, Kiess W, Rascher W, editors. Leptin - the voice of the adipose tissue. J&J Edition, JA Barth Verlag, Heidelberg, 1997]. In addition, leptin is thought to play an important role for reproduction and during gestation [Kiess W, Blum WF, Aubert ML. Leptin, puberty and reproductive function: lessons from animal studies and observations in humans. Eur J Endocrinol 1997;138:1-4; Barash IA, Cheung CC, Wigle DS, Ren H, Kabitting EB, Kuijer JL, Clifton DK, Steiner RA. Leptin is a metabolic signal to the reproductive system. Endocrinology 1996;133:3144-47; Chehab F, Lim M, Lu R. Correction of the sterility defect in homozygous obese female mice by treatment with the human recombinant leptin. Nature Genetics 1996;12:318-20; Kiess W, Schubring C, Prohaska F, Englaro P, Rascher W, Attanasio A, Blum WF. Leptin in amniotic fluid at term and at midgestation. In: Blum WF, Kiess W, Rascher W, editors. Leptin - the voice of the adipose tissue. J&J Edition, JA Barth Verlag, Heidelberg, 1997]. The purpose of this study was to gain more insight into a putative role of leptin during midgestation. Therefore we have measured leptin concentrations in maternal serum and amniotic fluid using a specific radioimmunoassay (RIA) employing human recombinant leptin for tracer and standard preparation [Blum WF, Kiess W, Rascher W, editors, Leptin - The voice of the adipose tissue. J&J Edition, JA Barth Verlag, Heidelberg, 1997; Blum WF, Englaro P, Heiman M, Attanasio Am, Kiess W, Rascher W. Clinical studies of serum leptin. In: Blum WF, Kiess W, Rascher W. Leptin - The voice of the adipose tissue. J&J Edition, JA Barth Verlag, Heidelberg, 1997; Blum WF, Englaro P, Heiman M, Attanasio AM, Kiess W, Rascher W. Plasma leptin levels in healthy children and adolescents: dependence on body mass index, body fat mass, gender, pubertal stage and testosterone. J Clin Endocrinol Metab 1997;82:2904-2910]. In addition, estriol, hCG and alphafetoprotein were measured in maternal serum. (ABSTRACT TRUNCATED)

Source density analysis of functional topographical EEG: monitoring of cognitive drug action.

Electrical changes of the brain induced by mental work in the presence or absence of a drug formulation containing dimethylaminoethanolorotrate (DMAE), vitamins and minerals were analysed. Sixty elderly volunteers (30 females and 30 males; aged 40 - 65) who lacked concentration and efficiency during mental exercise according to their own opinions participated in a double-blind, placebo-controlled study. The EEG recordings were carried out before and after 12 weeks medication and were analysed according to the electrical charges at the scalp surface (Laplacian estimate) followed by Fast Fourier Transformation to obtain quantitative data. Whereas no change of electrical charge could be observed after 12 weeks of treatment in the placebo group, the verum group taking 1 capsule per day of an established drug containing a biogenic amine-vitamin combination revealed decreases in theta power during rest and increases in absolute theta power induced by mental demand within the area known to change its electrical activity during mental exercise. In the light of the current hypothesis that high theta resting power and low increases at frontotemporal brain areas during mental work indicate mental impairment, treatment with the drug under investigation was seen to successfully reverse these changes. This drug effect was localized in the frontotemporal cortex in a statistically significant manner during both the memory and the symbol recognition tests. The observed effect is fully consistent with a previous study using Fourier transformed data from conventional EEG voltage recordings. It can be concluded that an analysis of EEG data by means of the charge mode provides an excellent tool to quantify drug effects especially in cognitive research. A second perspective arises from the fact that it should be possible to recognize mental impairments at a very early stage by using this method, thus providing the possibility of an early treatment.

DNA elimination and its relation to quantities in the macronucleus of Tetrahymena.

The macronucleus of Tetrahymena contains a large number of DNA molecules of subchromosomal size. They belong to about 270 species each one occurring at an average number of 45 copies. Macronuclei divide unequally and nothing is known of segregation control. This and the elimination and degradation of DNA during macronuclear amitosis make the clonal stability of macronuclei a problem of qualitative and quantitative control on a subchromosomal level. We studied the contribution of DNA elimination to the quantitative composition of the macronucleus cytophotometrically in single cells of different strains. This was done under standard conditions and under conditions known to influence the amount of macronuclear DNA. The following results were found: Elimination of DNA occurs at almost every division. The size of the elimination body is highly variable but still positively correlated with the macronuclear DNA content. In T. thermophila the amount of eliminated DNA is 2.5% of the G2 content and is not dependent on the growth state. It varies with species, amounting to as much as 8% in T. pigmentosa. During conditions which increase the macronuclear DNA content, very little DNA is eliminated. On the other hand, large amounts are eliminated under other conditions causing the macronuclear DNA content to decrease. DNA to be eliminated at division is synthesized at the same time as bulk DNA. We developed a computer program which helps us study the effects of DNA elimination and unequal divisions upon the copy numbers of subchromosomal DNA classes.(ABSTRACT TRUNCATED AT 250 WORDS)