Parallel changes between the percentage of fetal pituitary cells immunoreactive to oestrogen receptor α and the concentration of 17β-oestradiol in fetal and maternal plasma during gestation in sheep

2004 ◽  
Vol 16 (6) ◽  
pp. 611 ◽  
Author(s):  
Sheng Cui ◽  
Jia li Liu ◽  
Yu jing Shao ◽  
Jian Chao Zhang

The present study was designed to investigate the relationship between fetal sheep pituitary oestrogen receptor (ER) α expression and changes in fetal and maternal plasma 17β-oestradiol (E2) concentrations during gestation. The results revealed that immunoreactivity for ERα was located in the nuclei and distributed throughout the fetal pituitary gland during gestation. The percentage of ERα-positive cells was approximately 2% of the total cell population in female fetuses at Day 60 of gestation, increased to approximately 7% and 13% of the total cell population at Days 90 and 120 of gestation, respectively, and then declined to approximately 10% at birth. The fetal plasma E2 concentrations were approximately 19 and 71 pg mL−1 at Days 90 and 120 of gestation, respectively, and decreased to 22 pg mL−1 after birth. In male fetuses, plasma E2 concentrations and the percentage of ERα-positive cells were similar to values in female fetuses throughout gestation, except on Day 120 when the plasma E2 level in female fetuses was significantly higher than in male fetuses. These data demonstrate that changes in the percentage of fetal pituitary ERα-positive cells parallel fetal plasma E2 concentrations throughout gestation.

Blood ◽  
1959 ◽  
Vol 14 (4) ◽  
pp. 409-414 ◽  
Author(s):  
WILLIAM T. BURKE ◽  
CHARLES HARRIS

Abstract A method is described by which the total nucleated cell count of femoral bone marrow of the rat can be estimated and cell population expressed in terms of differential counts. Normal values of total nucleated cell counts and the cellular distributions are given for seven age groups. These data indicate considerable change in bone marrow total cell population in rats one to 10 weeks of age.


1997 ◽  
Vol 152 (3) ◽  
pp. 379-386 ◽  
Author(s):  
M B Nicol ◽  
J J Hirst ◽  
D Walker ◽  
G D Thorburn

Placental progesterone synthesis exposes the fetus to high levels of progesterone and progesterone metabolites during late gestation which may influence fetal behaviour. To determine the role of maternal progesterone synthesis in the control of fetal arousal state and fetal breathing movements (FBM), the effect of raising and lowering maternal progesterone concentrations was examined in chronically catheterised fetal sheep. Fetal and maternal vascular catheters, fetal tracheal and amniotic fluid catheters as well as electrodes for recording fetal electrocortical (ECoG), electro-ocular (EOG) and nuchal muscle electromyographic (EMG) activity were implanted between 118 and 122 days gestational age (GA). Progesterone, 100 mg, administered twice daily i.m. for 3 days (130–133 days GA) resulted in a marked elevation in maternal plasma progesterone concentrations (370 ± 121%, n=5, P<0·05), but had no effect on fetal plasma concentrations. Fetal EOG episodes and the duration of fetal behavioural arousal were significantly suppressed throughout the progesterone treatment period (74·4–81·1% and 58–65% respectively, P<0·05, n=5). Four ewes received Trilostane (25 mg i.v.), a 3β-hydroxysteroid dehydrogenase inhibitor, between 136 and 140 days GA. Maternal and fetal progesterone concentrations were significantly lowered by 60 min after treatment (19·8 ± 8·0% and 39·5 ± 24·3% respectively, P<0·05). The incidence of fetal EOG activity increased from a pretreatment level of 26·8 ± 1·5 min/h to 30·3 ± 2·8 min/h at 1–6 h and to 35·0 ± 1·7 min/h (P<0·05) during the 7–12 h after Trilostane treatment. The duration of FBM episodes was significantly higher at 1–6 h and 7–12 h after Trilostane treatment (19·5 ± 3·0 and 23·6 ± 5·5 min/h respectively, P<0·05) compared with pretreatment levels (11·2 ± 1·2 min/h). We conclude that increasing maternal progesterone levels suppresses fetal EOG activity and behavioural arousal, whereas reducing maternal progesterone synthesis leads to an elevation of EOG activity and FBM. Journal of Endocrinology (1997) 152, 379–386


1987 ◽  
Vol 252 (2) ◽  
pp. E279-E282 ◽  
Author(s):  
C. Y. Cheung ◽  
D. M. Gibbs ◽  
R. A. Brace

To determine atrial natriuretic factor (ANF) concentrations in the circulation and body fluids of adult pregnant sheep and their fetuses, pregnant ewes were anesthetized with pentobarbital sodium, and the fetuses were exteriorized for sampling. ANF concentration, as measured by radioimmunoassay, was 47 +/- 6 (SE) pg/ml in maternal plasma, which was significantly higher than the 15 +/- 3 pg/ml in maternal urine. In the fetus, plasma ANF concentration was 265 +/- 49 pg/ml, 5.6 times that in maternal plasma. No umbilical arterial and venous difference in ANF concentration was observed. Fetal urine ANF concentration (13 +/- 2 pg/ml) was significantly lower than that in fetal plasma, and was similar to that measured in amniotic and allantoic fluid. In chronically catheterized maternal and fetal sheep, fetal plasma ANF was again 5.1 times that in maternal plasma, and these levels were not different from those measured in acutely anesthetized animals. These results demonstrate that immunoreactive ANF is present in the fetal circulation at levels higher than those found in the mother. The low concentration of ANF in fetal urine suggests that ANF is probably metabolized and/or reabsorbed by the fetal kidney.


1988 ◽  
Vol 255 (3) ◽  
pp. R412-R417 ◽  
Author(s):  
C. E. Wood

Previous studies from this laboratory have demonstrated that intravenous infusions of hydrocortisone (cortisol) into fetal sheep at rates that produce plasma concentrations achieved during fetal stress inhibit fetal adrenocorticotropic hormone (ACTH) and renin secretion. The present study was designed to test for inhibition of fetal renin and ACTH after maternal adrenal secretion of cortisol. ACTH-(1-24) or saline infusion into 12 pregnant ewes (120-132 days gestation) at rates of 0, 1, 5, or 20 ng ACTH.kg-1.min-1 for 5 h produced dose-related increases in maternal plasma ACTH and cortisol concentrations and fetal plasma cortisol concentration. In the 20-ng.kg-1.min-1 group, increases in fetal plasma cortisol of 8.0 ng/ml (to 24.3 +/- 3.7 ng/ml) did not suppress basal fetal plasma renin activity. One hour after the end of the maternal vehicle or ACTH infusion, fetal ACTH secretion was stimulated by fetal intravenous infusion of sodium nitroprusside. In the 0-, 1-, and 5-ng.kg-1.min-1 groups, fetal ACTH responses to nitroprusside were suppressed in animals infused with ACTH. Together, these results indicate that the maternal adrenal secretion of cortisol inhibits stimulated secretion of ACTH but not renin in 120- to 132-day-gestation fetal sheep.


1970 ◽  
Vol 48 (2) ◽  
pp. 209-212 ◽  
Author(s):  
Vibeke E. Engelbert ◽  
Ann Dorothy Young

Erythropoiesis in peripheral blood of domestic birds was shown earlier to arise directly from the nucleus of mature erythrocytes as nuclear protuberations that later broke free. Three to seven percent of new red cells originated in this way from clone cells.Investigations of peripheral blood in reptiles has further demonstrated formation of nucleated red cells as clones from nuclear buds of mature erythrocytes. Clone cells plus new immature red cells constitute, in Sphenodon punctatus, 8–18% and, in turtle, Malaclemys terrapin, 18–25% of the total cell population. Some lymphocytes and granulocytes appear also to arise from nuclear buds. Thrombocytes were present in some animals, absent in others, but were not counted in the present work.


1966 ◽  
Vol 12 (2) ◽  
pp. 255-261 ◽  
Author(s):  
H. Sato ◽  
B. B. Diena ◽  
L. Greenberg

Spheroplast induction and lysis of 6 BCG strains of Mycobacterium tuberculosis by glycine and lysozyme was studied in various media. Spheroplast production was noted in only three strains involving 20% of cell populations. Lysis, as distinct from spheroplast induction, occurred in Dubos medium containing 1.5% glycine and 0.01% lysozyme after 24–48 hours of incubation. Estimation from a standard curve indicated 40 to 70% lysis of the total cell population after 7–10 days of incubation.Similarly, lysis of BCG cells occurred when the inducers, glycine, lysozyme, and lithium chloride, were added to nitrogen-starved cultures grown in Aldridge synthetic medium for 7 to 8 days.


2011 ◽  
Vol 19 (1) ◽  
pp. 35 ◽  
Author(s):  
Grethe Badsberg Samuelsen ◽  
Nenad Bogdanović ◽  
Henning Laursen ◽  
Niels Graem ◽  
Jørgen Falck Larsen ◽  
...  

In this study the material comprises brains from three aborted fetuses and two fullterm infants who died at birth.The gestational ages ranged from the 22nd week to term. All cases were without malformations, known chromosomal abnormality, hydrops, and systemic infections, and all had normal birth weights with fetal growth indices (observed birth weight/expected mean birth weight) between 0.9 - 1.05. The preliminary results show a five fold increase in the total cell population in the marginal zone/cortical plate, MZ/CP (future neocortex), from week 22 until term. In the transient subplate zone, SP, the total cell number was more than doubled from week 22 to week 30-35, and then decreased towards term. In the intermediate zone, IZ (future white matter), the total cell population was doubled from week 22 until term. The total cell number in the entricular/subventricular zone, VZ/SZ (germinal matrix), was reduced by a factor of five from week 22 until term. A histological differentiation between neurons and glial cells was not possible. The optical fractionator was used to estimate the total cell population in four characteristic developmental zones in the human fetal brain. Fetal brain tissue undergoes considerable and rather unpredictable shrinkage during fixation. However, using the fractionator principle it is possible to eliminate this problem, provided that the structure of interest (one brain hemisphere) is fully intact.


Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 215-228
Author(s):  
D. Forman ◽  
D. R. Garrod

Immunofluorescent staining of the prespore cells of the cellular slime mould Dictyostelium discoideum was carried out using a heterologous spore antibody. The highly specific staining of the prespore vesicles (PSVs) within the prespore cells enabled quantitative determinations to be made of the rate and extent of development of these cells throughout the life cycle. The results showed that PSVs first appeared in a large proportion of the cells shortly after the cells had chemotactically aggregated into multicellular masses. During the later phases of the life cycle, the proportion of cells containing PSV increased, as did the fluorescent intensity of their PSVs, until the early culmination stage of development when 85–90 % of the total cell population contained PSVs. Lowering the temperature of development delayed the onset of vesicle formation and decreased the proportion of prespore cells in the total cell population. Changing the growth conditions of the cells prior to multicellular development also had a significant effect on the proportions of prespore cells, as did the use of a mutant known to give rise to fruiting bodies with a reduced number of spores. The comparability between these estimates of prespore cell proportions at culmination and previously reported spore:stalk ratios within fruiting bodies confirms the view that PSVs are reliable indicators of prespore cells. The finding that temperature and growth conditions and the use of mutants all of which are known to affect spore:stalk ratios, also all affected prespore proportions in the expected direction, adds further weight to this argument. The fact that prespore cells are beginning to differentiate early in the multicellular phase of the life cycle and the related finding that such differentiation always precedes formation of the grex tip are results of considerable importance to the development of a model for pattern formation in D. discoideum.


1957 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
JOYCE E. SANTLER

SUMMARY The thyroid gland of adult male albino rats enlarged during a period of 30 days of thiouracil treatment. During 75 days after cessation of this treatment there was a regression of the enlarged gland, but not to normal values of weight, volume or total cell population. The regression did not, however, involve any appreciable drop in the numbers of follicular cells. Decrease in the volume of follicular tissue was therefore due to shrinkage of individual follicular cells. The stromal cell population decreased, especially during the first 7 days after the withdrawal of thiouracil, and at the end of the experiment the proportion of stromal cells to follicular cells had returned to normal. The first 7 days was also the time of greatest regression in weight, volume and blood vessel space in the thyroid, these values showing only slight further reduction in the groups killed 30 and 75 days after the withdrawal of goitrogen.


2009 ◽  
Vol 41 (6) ◽  
pp. 408-413 ◽  
Author(s):  
P. Manolakou ◽  
R. Angelopoulou ◽  
C. Bakoyiannis ◽  
E. Psathas ◽  
E. Bastounis ◽  
...  

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