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At least 685 records · Page 38Linked to original sources
PubMed2002

Effects of chlorophyllin on mouse embryonic and fetal development in vivo.

Chlorophyllin (CHL) has proven that there is antimutagenic and anticarcinogenic activity in several organisms without causing lethal effects. However, there is no information about its effects when it is administered in gestation. In the present study, we assessed possible effects of CHL when it was administered to CD-1 mice on the 8th day of gestation using the same doses and administration route used in ours previous antimutagenic and antigenotoxic studies. Females were exposed to a single dose of CHL by i.p. injection (20, 40, 50, or 100mg/kg b.w.). On day 18 all dams were subjected to cesarean section and the fetuses were examined with common teratological methods. Results show that CHL-treatment induced total litter loss and is dose-dependent, probably due to either the interaction between CHL and some general control mechanisms of embryo development or by an impairment of maternal-fetal interactions. The analysis of uterine horns of the CHL-treated females with total litter loss revealed the presence of green rings in the uterus. Results show the inverse relationship between the number of live implants and the frequency of green rings, indicating implantation sites where embryo death and early resorptions occurred. Although CHL was given in a single dose on day 8 in this study, the results indicate that CHL is associated with significant embryo lethality.

Animals↗
PubMed1980

Influence of maternal distress during pregnancy on fetal development and mortality.

The children of 1,263 women whose applications for legal abortion in 1960 had been refused, were compared with the next children born in the same delivery wards. Thus paired, matched controls were obtained and the children were compared with regard to height and weight in relation to gestational age, prematurity, perinatal mortality and mortality up to 12 years of age. There was a significantly lower number of stillbirths in the proband series, which is probably due to an increased number of abortions of less viable fetus. There were no differences in weight and height development, prematurity or neonatal and subsequent mortality.

Adolescent↗
PubMed1992

The influence of thyroxine on the differentiation of adipose tissue and skin during fetal development.

Preobese fetuses have elevated thyroid hormone levels and depressed growth hormone levels relative to lean fetuses. Therefore, we are studying various experimental fetal pig models to explore the relationship between endocrine status and onset of obesity. In the present study, intact and hypophysectomized (d 70) fetuses were implanted with thyroxine (T4) pellets on d 70 of gestation, and blood, adipose tissue, and skin samples were obtained upon removal of d 90 of gestation. Body weights were similar for all groups and T4 treatment reversed myxedema in hypophysectomized fetuses. Serum T4 levels were elevated (p less than 0.05) and skin and hair development were enhanced (p less than 0.05) to a similar degree by T4 treatment in intact and hypophysectomized fetuses. However, T4 did not influence adipose tissue development in intact fetuses, but markedly enhanced development in hypophysectomized fetuses. For instance, fat cell size and lipogenic enzyme activities in hypophysectomized fetuses were increased (p less than 0.05) by 5-mg and 15-mg T4 treatments, with a marked increase (p less than 0.05) in apparent fat cell number with the 15-mg T4 treatment. In contrast, there was no effect of T4 (15 mg) on these parameters in intact fetuses. Therefore, fetal obesity may be directly associated with elevated thyroid hormone levels and suppressed growth hormone levels, but not with elevated T4 levels alone.

Adipose Tissue↗
PubMed1997

[Embryo-fetal development in the early stages of pregnancy].

The introduction of high resolution transvaginal US in obstetrical clinical practice permits earlier and more detailed visualization of embryo-fetal structures in early pregnancy. A transvaginal US examination with a high-resolution probe (5.0-6.0 MHz) was performed in 1246 pregnant patients between 9 and 16 weeks of gestation and known gestational age. Ten embryo-fetal biometric parameters were measured (crown-rump length, biparietal diameter, head circumference, transverse cerebellar diameter, thoracic circumference, mean abdominal diameter, abdominal circumference, femur length, humerus length and foot length). Reference ranges with 5 degrees and 95 degrees percentile intervals were constructed for all biometric parameters in relation to gestational age. Only one scan per patient was considered for this study. All the parameters evaluated demonstrated a high correlation with gestational age at polynomial regression analysis. The mean coefficient of determination (r2) ranged from 97.15 for biparietal diameter to 88.17 for transverse cerebellar diameter. The data are useful as reference range for the assessment of normal embryofetal development by transvaginal US in the early stages of pregnancy.

Embryonic and Fetal Development↗
PubMed1987

Disruption of embryonic and fetal development due to preimplantation chemical insults: a critical review.

Descriptive teratology has developed several fundamental precepts, two of which can now be challenged on the basis of experimental evidence. The first is that prior to implantation the developing embryo is not susceptible to survivable defects from chemical injury. The second is that developmental defects cannot be due to mutational events since rare events seem unlikely to explain alterations in large populations of cells. This review presents current experimental evidence demonstrating that the effects of chemical exposure on blastocyst stage embryos may be manifest long after the time of insult and that subtle nonlethal mutations may have a role in poor fetal performance after early chemical exposures.

Animals↗
PubMed1977

Dietary restriction and fetal development.

The effect of deficient nutrition of pregnant Wistar rats on the fetal weight has been studied. It has been established that the fetal weight of the group of rats fed with a restricted amount of stock diet lags behind the fetal weight of the group receiving unrestricted amounts of the same stock diet. The differences in weight between the 2 groups were, on each day of the observation period, significant at the level of p less than 0.05 and p less than 0.01, respectively.

Animals↗
PubMed1986

Acetyl-CoA carboxylase of sheep adipose tissue: problems of the assay and adaptation during fetal development.

The rate of fatty acid synthesis of perirenal adipose tissue of fetal lambs decreased by 90% during the last month of gestation. There was also a 90% decrease in the activity of fatty acid synthetase during this period, but the activity of this enzyme exceeded lipogenic flux by a factor of 10. The activity of acetyl CoA carboxylase in the active state (initial activity) was very similar to the lipogenic flux in adipose tissue from lambs at 120 d of gestation; although activity decreased towards term, the decline was insufficient to account for the fall in rate of fatty acid synthesis. The study also shows that assay of acetyl CoA carboxylase in the active state of ovine adipose tissue and of caprine mammary gland requires the presence of citrate, thus differing from that for rat adipose tissue. Evidence that pyruvate carboxylase can interfere in the assay of acetyl CoA carboxylase also is presented.

Acetyl-CoA Carboxylase↗
PubMed1998

Hepatocyte growth factor activator: a possible regulator of morphogenesis during fetal development of the rat gastrointestinal tract.

The role played by the hepatocyte growth factor activator (HGFA) during morphogenesis of the gastrointestinal tract was investigated in fetal rats between days 16 and 21 of gestation. By our recently established method using chelation and dissecting microscope, samples could be separated into epithelium and mesenchyme, essentially without cross-contamination. The expression of the gene for HGFA together with those for hepatocyte growth factor (HGF) and its receptor, c-met, was investigated in each tissue element by RT-PCR. In the fetal rat gastrointestinal tract, mRNA signals for the HGFA gene were observed only in epithelia expressing c-met mRNA. In contrast, expression of HGF mRNA was limited to the mesenchymal elements, indicating the presence of a local HGF system in the gastrointestinal tract; an inactive form of HGF (proHGF) is secreted from the mesenchyme and then cleaved into the active form by HGFA secreted by the target epithelia. During the period of morphogenesis and histodifferentiation in the gastrointestinal tract, enhanced expression of the genes for HGF and its receptor/c-met was evident, with elevated HGFA mRNA level observed throughout the gastrointestinal tract except in the forestomach, where mRNA expression was barely detectable. These results strongly suggest the possibility that morphogenesis of the gastrointestinal tract is regulated not only by a local increase in production of HGF, but also by enhanced proteolytic activation of proHGF. Thus, it is probable that locally synthesized HGFA plays a significant role as a regulator of the morphogenic action of HGF during gastrointestinal tract development.

Animals↗
PubMed1993

Myosin expression in semitendinosus muscle during fetal development of cattle: immunocytochemical and electrophoretic analyses.

The pattern of expression of different types of myosin and the development of different muscle cell populations were studied in the semitendinosus muscle of cattle from 39 d of gestation to 30 d of post-natal life. Monoclonal antibodies specific to different myosin heavy chains were used. Two cell generations were identified during myogenesis. They appeared successively and were characterized by different patterns of expression of myosins. The first population, which was present from the first stage studied (39 d of gestation), gave rise to type I fibers, which, in the mature animal, express only slow myosin. A second generation became differentiated at about 120 d of fetal life and then developed into type II fibers (IIa, IIb or IIc). The beginning of differentiation was characterized in all the cell populations by the expression of specific types of embryonic or fetal myosins. A comparison of these results with findings from previous works shows a marked similarity between species in the pattern of myogenesis but great differences in the length of the different stages of development. In this respect, myogenesis in cattle closely resembles that in man.

Animals↗
PubMed1998

Effect of prenatal exposure to diethylstilbestrol on Müllerian duct development in fetal male mice.

The clinical use of diethylstilbestrol (DES) by pregnant women has resulted in an increased incidence of genital carcinoma in the daughters born from these pregnancies. Also, in the so-called DES-sons abnormalities were found, mainly, the presence of Müllerian duct remnants, which indicates that fetal exposure to DES may have an effect on male sex differentiation. Fetal regression of the Müllerian ducts is under testicular control through anti-Müllerian hormone (AMH). In male mice, treated in utero with DES, the Müllerian ducts do not regress completely, although DES-exposed testes do produce AMH. We hypothesized that incomplete regression in DES-exposed males is caused by a diminished sensitivity of the Müllerian ducts to AMH. Therefore, the effect of DES on temporal aspects of Müllerian duct regression and AMH type II receptor (AMHRII) messenger RNA (mRNA) expression in male mouse fetuses was studied. It was observed that Müllerian duct regression was incomplete at E19 (19 days post coitum), upon DES administration during pregnancy from E9 through E16. Furthermore, analysis of earlier time points of fetal development revealed that the DES treatment had clearly delayed the onset of Müllerian duct formation by approximately 2 days; in untreated fetuses, Müllerian duct formation was complete by E13, whereas fully formed Müllerian ducts were not observed in DES-treated male fetuses until E15. Using in situ hybridization, no change in the localization of AMH and AMHRII mRNA expression was observed in DES-exposed male fetuses. The mRNA expression was quantified using ribonuclease protection assay, showing an increased expression level of AMH and AMHRII mRNAs at E 13 in DES-exposed male fetuses. Furthermore, the mRNA expression levels of Hoxa 11 and steroidogenic factor-1 (SF-1) were determined as a marker for fetal development. Prenatal DES exposure had no effect on Hoxa 11 mRNA expression, indicating that DES did not exert an overall effect on the rate of fetal development. In DES-exposed male fetuses, SF-1 showed a similar increase in mRNA expression as AMH, in agreement with the observations that the AMH gene promoter requires an intact SF-1 DNA binding site for time- and cell-specific expression, although an effect of DES on SF-1 expression in other tissues, such as the adrenal and pituitary gland, cannot be excluded. However, the increased expression levels of AMH and AMHRII mRNAs do not directly explain the decreased sensitivity of the Müllerian ducts to AMH. Therefore, it is concluded that prenatal DES exposure of male mice delays the onset of Müllerian duct development, which may result in an asynchrony in the timing of Müllerian duct formation, with respect to the critical period of Müllerian duct regression, leading to persistence of Müllerian duct remnants in male mice.

Animals↗
PubMed1981

Hepatocyte differentiation during early fetal development in the rat.

Rat hepatocyte differentiation between day 12 and 19 of fetal life was studied by electron microscopy. The cytoplasmic structures involved in synthetic and secretory function, i.e., rough endoplasmic reticulum and Golgi apparatus, appear to be the first to differentiate, and their development is probably related to the secretion of different kinds of plasma proteins. The cytoplasmic organelles involved in other hepatic functions develop later: lysosomes from day 15, peroxysomes, glycogen rosettes and smooth endoplasmic reticulum still later. However, the morphological differentiation of bile canaliculi begins from day 12.

Animals↗
PubMed1988

Immunocytochemical localization of gamma-glutamyltranspeptidase during fetal development of mouse kidney.

In the fully developed kidney, gamma-glutamyltranspeptidase is localized predominantly to the apical plasma membrane of the proximal tubules. The appearance of this activity during murine fetal nephrogenesis was quantitated using a sensitive fluorometric assay, and development of membrane polarity was assessed by immunocytochemistry. Specific activity of the transpeptidase in 13-day fetal kidney was approximately 1 mU/mg protein. Between 13-21 days of gestation, total transpeptidase activity increased 7500-fold, whereas specific activity increased 50-fold. At 13 days of gestation, gamma-glutamyltranspeptidase immunoreactivity is localized to the apical surfaces of developing renal vesicles and the proximal segment of the S-shaped tubules. The organized cell structures have tight tubular junctions but lack a well-defined brush-border membrane. By 15 days of gestation, immunostaining of the apical surface of developing proximal segments is more prominent, and slight reactivity of the basolateral membrane is evident. By 17 days of gestation, the kidney is organized into discrete zones. The large increase in gamma-glutamyltranspeptidase activity correlates with the appearance of increased immunostaining of the developing brush-border membranes of the proximal tubules contained in the inner cortex. A very similar although somewhat delayed pattern of appearance of transpeptidase activity and immunostaining was observed in metanephric organ culture. Induction of proximal tubular cyst formation had no effect on the increase in transpeptidase activity that occurred during organotypic nephrogenesis.

Animals↗
PubMedDate not supplied

Oxonic acid and fetal development: I. Embryotoxicity in mice.

Feeding the uricase inhibitor potassium oxonate (K Ox) as 3( of the diet to pregnant mice during days 8-10 postconception caused a 95-98% incidence of embryonic mortality with resorption. The same treatment during days 10-13 of gestation caused no changes in litter size and fetal weight; however, if in addition to feeding K Ox, three concurrent i.v. injections of 2.5 mg/day of Na urate (Na UR) were given then 47% of the mouse fetuses were killed and resorbed. Intravenous Na urate alone during the same stages of early and middle pregnancy had no effect on fetal survival or development. A 3.6% incidence of cleft palate was caused in mice treated with the combination of K Ox and Na UR during middle pregnancy. In groups of mature nonpregnant female mice exposed to the same treatment regimens, serum uric acid, potassium and sodium were elevated in a treatment-related manner. Serum urea levels were unchanged. K Ox is lethal to mouse fetuses during early embryonic development. Hyperuricemia, hyperkalemia or hypernatremia are maternal alterations which may be responsible for, or contribute to this effect.

Animals↗
PubMed1998

The generation of human gammadelta T cell repertoires during fetal development.

The nature of how human gammadelta T cells are normally generated is not clear. We have used an RT-PCR assay and DNA sequencing to identify and compare delta-encoded TCRs (TCRDs) that are generated de novo in the fetal gut, liver, and thymus and to determine when, where, and how the TCRD repertoire is established during normal embryonic development. Rearranged TCRDV genes are first expressed outside of the thymus in the liver and primitive gut between 6 and 9 wk gestation. Although DV1Rs and/or DV2Rs predominated, differences in the pattern of TCRDV gene rearrangement and transcription in each tissue during ontogeny were identified. Specific, DV2-encoded TCRs are highly conserved throughout ontogeny in the tissues from the same and between genetically distinct donors. Although the thymic and intestinal gammadelta T cell repertoires partially overlap early in development, they diverge and become nonoverlapping during the second trimester, and the generation of the intestinal gammadelta T cell repertoire is characterized by differences in the processing of DV1Rs and DV2Rs. Whereas the structural diversity of DV1Rs progressively increases during gut development up to birth, DV2Rs have limited structural diversity throughout ontogeny. Together, our findings provide evidence for the ability of different fetal tissues to support the development of gammadelta T cells.

Animals↗