Effects of pregnancy and lactation on the serum selenium content of rats

The serum selenium content of rats was measured by means of neutron activation analysis. It was found to drop between the 12th day of pregnancy and term and to return to its original level within 2 days after delivery. Hysterectomy on the 10th day of gestation prevented this decrease. Nursing had no influence on the element level. The findings suggest that placental secretions might be involved in the control of the serum selenium content of rats during pregnancy.     

Effects of pregnancy and lactation on the serum selenium content of rats

Summary The serum selenium content of rats was measured by means of neutron activation analysis. It was found to drop between the 12th day of pregnancy and term and to return to its original level within 2 days after delivery. Hysterectomy on the 10th day of gestation prevented this decrease. Nursing had no influence on the element level. The findings suggest that placental secretions might be involved in the control of the serum selenium content of rats during pregnancy.     

Autoradiographic study of proliferative activity and cell migration in the adrenal cortex in fetal and neonatal rats]

On the 20th day of fetal life the cell proliferation is higher in the zona glomerulosa. The fate of marked cells in each cell compartment shows centripetal migration. Their displacement, from the 20th day of pregnancy up to five days post-partum, while at that time the adrenal growth is slowered down, suggests a real migration.     

Influence of N-methylformamide on the development, the NAD synthesis, and the activity of the ADPR transferase of rat embryos

When N-methylformamide is administered to rats on the 11th day of pregnancy approximately 50% of the fetuses are resorbed and a reduced weight of the developed animals is found in comparison to the controls on the 21th day (delivery by Caesarian section). The toxic effect is increased by using nicotinamide and methionine. If a combination of these substances is employed practically all fetuses are resorbed. Tryptophan, however, has a considerably protective influence. N-Methylformamide has no influence on the NAD-synthesis induced by nicotinamide or tryptophan. It does, however, inhibits the activity of the ADPR transferase.     

Glutathione peroxidase in erythrocytes and plasma of rats during pregnancy and lactation

Summary The glutathione peroxidase activity in the plasma of rats on the 20th day of pregnancy was found to be 50% lower than in nulliparous control animals. During lactation, the level rose again but was still significantly different from that of the control rats on the 20th day post partum. The erythrocyte enzyme activity remained unchanged.Acknowledgments. We should like to thank Dr A. Wendel, Physiologisches Institut der Universität Tübingen, for his advice on carrying out the glutathione peroxidase assay.     

Bacterial endotoxin and impaired fetal development

Summary Small doses ofE. coli endotoxin given to pregnant mice on the 13th day of pregnancy caused only a mild maternal illness but induced resorption of approximately half the number of fetuses in each mouse. The remaining live fetuses developed normally and showed no evidence of retarded growth or malformations. The weights of their placentas and maternal spleens increased significantly. Endotoxin given on the 6th day of pregnancy caused a small reduction in fetal weights.Acknowledgments. I am indebted to Mrs.Heather Sandison for technical assistance and to Mr.M. J. R. Healy for statistical examination of the results. Dr.A. B. G. Lansdown kindly advized on the interpretation of histological findings.     

Effect of methyl ester of aristolic acid fromAristolochia indica Linn. on fertility of female mice

Summary Methyl ester of aristolic acid, a pure compound isolated from the roots ofAristolochia indica (Linn.), was found to exert 100% abortifacient activity at a single oral dose of 60 mg/kg b. wt when administered on 6th or 7th day of pregnancy; 20 and 25% abortifacient effect were observed at the same dose on day 10 and 12, respectively.The authors wish to thank Dr S.C. Pakrashi and his associate Mr P.P. Ghosh Dastidar for the compound. Thanks are also due to the Director General of Indian Council of Medical Research for granting a fellowship to one of them (C.S.).     

Effect of antiblastokinin on rabbit pregnancy

On different days following coitus, i.e., during the first stages of pregnancy, adult female rabbits were treated with antiblastokinin obtained from a chicken. A high prenatal mortality was observed and a reduction of the weight in the stillborn of the rabbits treated. The antiblastokinin produces evident biological effect about the 4th day following coitus, during the period of maximum production of blastokinin by the endometrium in vivo.     

Serotoninergic innervation of the paraventricular organ in chick embryo and chick; histofluorescence and autoradiography study optic and electron microscopy]

Fluorescence microscopy (Falck and Hillarp technique) of 11th day old chick embryo shows aminergic neurons and processes in the paraventricular organ area. Administration of tritiated amines permits us to observe uptake and storage of serotonin only as early as the 10th day; this suggests a very early hypothalamic serotoninergic nervous system differentiation.     

Electrophoretic profiles of proteins and glycoproteins of chick embryo fibroblasts during development]

The variations of proteins and glycoproteins of Chick embryo fibroblasts are studied during development. This investigation is carried out using polyacrylamide disc gel electrophoresis in SDS. Two glycoproteins of high apparent molecular weight (250,000 and 200,000) undergo quantitative modification: they increase from the 8th to 12th day of development and then remain unchanged to the 16th day. They are cell surface components as suggested by fluorescamine labelling and trypsin sensitivity. The results are discussed in terms of relationship between tumor- and embryo cells.     

Sexual differences in the development of plasma thyroxine levels in the embryo and young chick]

Plasma thyroxine (T4) levels were separately ascertained in male and female embryo and young chicken from the 12th day of incubation till the 4th day after hatching by the thyroxine binding globulin technique. In both sexes, plasma T4 reach a peak the 20th day of incubation, but values are significantly higher in females. A sharp decrease occurred thereafter, plasma T4 tending toward adult values the 4th day after hatching.     

Luteolytic action of LHRH in women]

Several subcutaneous administrations of 250 microgram of LHRH (4 or 5 adminstrations at 4-hourly intervals per day) between the 2nd and 7th day post-ovulation in 4 normal women led to early luteolysis as demonstrated by a fall in serum progesterone concentration and early onset (2 to 3 days earlier) of menstruation.     

Blood histamine and response of spleen cells to phytohemagglutinins during moderate magnesium deficiency in the rat]

Blood histamine and spleen cell stimulation index by PHA were determined in either magnesium deficient or control Rats. Between the 10th and 17th days of diet (hyperemia and dermatosis period), histaminemia was significantly higher in deficient animals (485 ng/ml) than in control ones (112 ng/ml), but at the 32nd day it came back to normal values. The mean spleen cell stimulation index by PHA was depressed in deficient animals mainly between the 10th and 17th day of the deficiency; 33% of control mean value. A negative correlation is found between histamine level and stimulation index.     

Developmental nicotine exposure induced alterations in behavior and glutamate receptor function in hippocampus

In the developing brain, nicotinic acetylcholine receptors (nAChRs) are involved in cell survival, targeting, formation of neural and sensory circuits, and development and maturation of other neurotransmitter systems. This regulatory role is disrupted when the developing brain is exposed to nicotine, which occurs with tobacco use during pregnancy. Prenatal nicotine exposure has been shown to be a strong risk factor for memory deficits and other behavioral aberrations in the offspring. The molecular mechanisms underlying these neurobehavioral outcomes are not clearly elucidated. We used a rodent model to assess behavioral, neurophysiological, and neurochemical consequences of prenatal nicotine exposure in rat offspring with specific emphasis on the hippocampal glutamatergic system. Pregnant dams were infused with nicotine (6 mg/kg/day) subcutaneously from the third day of pregnancy until birth. Results indicate that prenatal nicotine exposure leads to increased anxiety and depressive-like effects and impaired spatial memory. Synaptic plasticity in the form of long-term potentiation (LTP), basal synaptic transmission, and AMPA receptor-mediated synaptic currents were reduced. The deficit in synaptic plasticity was paralleled by declines in protein levels of vesicular glutamate transporter 1 (VGLUT1), synaptophysin, AMPA receptor subunit GluR1, phospho(Ser845) GluR1, and postsynaptic density 95 (PSD-95). These results suggest that prenatal nicotine exposure by maternal smoking could result in alterations in the glutamatergic system in the hippocampus contributing to the abnormal neurobehavioral outcomes.     

A novel uterine lipocalin supporting pregnancy in equids

Horses, donkeys, and therefore, probably all equids, secrete a nonglycosylated, progesterone-dependent, 19-kDa protein (P19) into the uterine lumen during early pregnancy, and significant quantities of it are taken up by the developing conceptus. Sequence analysis and structural modelling have identified P19 as a lipocalin with greatest similarity to the murine major urinary protein lipocalins. However, lack of strong identity with any particular group of lipocalins and several unusual structural features, including a unique amino acid triplet within one of the invariant domains and an unusual external tryptophan residue, classify it as a new member of the lipocalin family. P19 is therefore likely to be a transport protein involved in supporting early embryonic development. Preliminary evidence using recombinant-derived P19 and fluorescently tagged ligands suggests that it may transport a fatty acid or retinol-like molecule. Although an initial search failed to identify homologues of P19 in other mammals, they may nevertheless exist but are synthesised and secreted in much smaller quantities, making them difficult to detect. Equids appear to need particularly large quantities of the protein during early pregnancy because of the unusually late implantation in this species and the presence of a capsule surrounding the conceptus until about day 23 of gestation.     

Quantitative Bestimmung von RNS-Fraktionen im Gehirn frisch geschlüpfter Bienen (Apis mellifica)

Summary In the brain of the honeybee (Apis mellifica), it was found that the rRNA content decreases rapidly during the first 2 days of adult life. An increase is observed from days 3 to 5, followed by another decrease to a level inferior to that of day 2 to 3. Except for a rise on the 5th day, 4s RNA remains constant. An unidentified RNA fraction of low molecular weight (D) sharply decreases on day 5. The possibility is discussed that these results reflect changes in RNA metabolism that can be related to the sequences of activity observed in the bees during the first 9 days after hatching.     

Ontogenetic analysis of the theta rhythm during paradoxical sleep in rats]

In the rat, an ontogenetic study of theta rhythm during paradoxical sleep shows a clear evolution between the 14th and the 30th postnatal day. During this period, its mean frequency increases from 5 to 7 cycles per second, and its spectrum shows significant changes. These parameters (mean frequency and spectral components) of the theta rhythm could be a useful index of brain maturation in the rat.     

Effect of Corynebacterium parvum on serum lysozyme (muramidase) levels (author's transl)]

An i.v. injection of 548 microgram of killed Corynebacterium parvum into C57B1 mice leads to significant changes in serum lysozyme (muramidase) levels. After an initial fall at 24 h, the activity of the enzyme increased progressively, reached a peak on the 9th day and returned to control range after the 15th day.     

Demonstration of a basal lamina in cocultures of thyroid cells and embryonal swine skin cells]

Porcine thyroid and embryo skin cells were isolated and cultured. Cultures from each kind of cells, as well as cocultures were fixed twice a week for electron microscopy. On day 8th a basal lamina like material appears only in the cocultures, along the basal plasmalemma of the reassociated thyroid cells. This amorphous material increases up to day 17th.