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At least 1,099 records · Page 61Linked to original sources
PubMed1980

Embryonal and fetal development of capillaries: microangiographic investigations. II. The telencephalon.

The development of the intracerebral capillaries of the telencephalon was studied by the combined techniques of microangiography and histology in embryos and fetuses of cattle and pigs. In the telencephalic colliculi ganglionares, vascularization starts during the 4th week of gestation and leads to the formation of a peripheral and a central arterial system separated by the internal capsule. Capillary development within the pallium occurs 3 weeks later and consists in the formation of longitudinal arteries, concentrically arranged rings of deviations and bifurcations, and a periventricular capillary network.

Angiography↗
PubMed1987

2-D gel membrane protein patterns during fetal rat hepatocyte development.

Fetal hepatocytes from rats of 13-20 days of gestation were 125I/surface-labelled. Autoradiographs of the plasma membrane proteins, analyzed by 2-D gel electrophoresis, were compared with those from adult hepatocytes and two hepatoma lines. The autoradiographic patterns of membrane proteins from 13 and 15 day fetal hepatocytes were similar. Between days 13 and 20 of gestation, at least 24 new iodinatable proteins appeared in the plasma membrane of fetal hepatocytes. Whilst between day 20 of gestation and adult life, at least 21 new membrane proteins appeared. Two membrane proteins, one acidic (MW 25,000) and a more basic protein (MW 45,000) were present in fetal hepatocytes but absent from adult hepatocytes. The membrane protein patterns from two hepatoma lines were less complex than those of adult hepatocytes.

Animals↗
PubMed2005

Thyroid hormones and fetal brain development.

Thyroid hormones are intricately involved in the developing fetal brain. The fetal central nervous system is sensitive to the maternal thyroid status. Critical amounts of maternal T3 and T4 must be transported across the placenta to the fetus to ensure the correct development of the brain throughout ontogeny. Severe mental retardation of the child can occur due to compromised iodine intake or thyroid disease. This has been reported in areas of the world with iodine insufficiency, New Guinea, and also in mother with thyroid complications such as hypothyroxinaemia and hyperthyroidism. The molecular control of thyroid hormones by deiodinases for the activation of thyroid hormones is critical to ensure the correct amount of active thyroid hormones are temporally supplied to the fetus. These hormones provide timing signals for the induction of programmes for differentiation and maturation at specific stages of development. Understanding these molecular mechanisms further will have profound implications in the clinical management of individuals affected by abnormal maternal of fetal thyroid status.

Animals↗
PubMed1986

[Studies on polyamines in the developing rats tissues].

Polyamines were determined by a rapid and simplified HPLC method, in the tissues of normal developing and experimental IUGR (intrauterine growth retardation) rats. Two types of experimental IUGR were induced by maternal starvation and ligature of uterine vessels. On the 20th day of gestation polyamine levels in tissues were compared with untreated controls. In normal developing fetal liver the levels of putrescine and spermidine were higher than those in adult. In particular, the putrescine level on the 15th day of gestation was about 50 times higher than that in adult. In the neonatal period the increases in putrescine and spermidine were proceeding to those of nucleic acids. On the contrary, the spermine levels in fetal liver was not higher than in adult liver. In fetal brain, the levels of the three polyamines were higher than those in adult brain. In IUGR rats the results were characteristic in liver, namely, the putrescine level was significantly decreased, on the other hand, spermidine and spermine levels significantly increased compared with the untreated control levels. No significant changes in polyamine level were observed in brain. In placenta, only the spermine level was increased compared with the untreated control level. These results suggest that there is a close relationship between polyamine and fetal development, and putrescine may play an important role as the trigger in fetal development.

Animals↗
PubMed1996

Flow cytometric sorting of sperm: influence on fertilization and embryo/fetal development in the rabbit.

Viable, intact rabbit sperm, prepared, processed, and flow cytometrically sorted, were used in this study to determine the influence of flow sorting on fertilization and embryo development. In experiment I, flow-sorted or control (unstained and unsorted) sperm were surgically inseminated into the uterine horn of hormonally primed does (10 to 12 does per time point). At 42 hr postsurgical insemination, flushed embryos were assessed for development. Fetal development was determined at day 7, day 14, and day 21 post-surgical insemination. Embryos resulting from does surgically inseminated with control sperm at 42 hr post-insemination were observed to be at the early morula stage of development (> 16 cell), whereas embryos from does inseminated with flow sorted sperm were at the 8- to 16-cell stage. No difference was observed between treatments at day 7, 14, or 21, however, there was a significant decrease in fetus number per doe inseminated with flow-sorted sperm over time. In experiment II, mature oocytes were flushed from the oviducts of superovulated does and coincubated in vitro (IVF) with flow-sorted or control rabbit sperm. Oocytes observed at 6 hr post-coincubation exhibited swollen sperm heads in the cytoplasm, demonstrating that fertilization had occurred (2 PN + T). There was a higher percentage of fertilized oocytes by 8 hr post-coincubation for both control (31%) and flow-sorted sperm (31%) when used for IVF. By 10 and 12 hr post-coincubation, little difference was observed in the number of fertilized oocytes between sperm treatments (52% and 66% for control vs. 57 and 54% for flow-sorted, respectively). These studies demonstrate that flow-sorted sperm are capable of fertilizing mature oocytes under in vitro conditions. In addition they show that flow sorting may not negatively influence fertilization events, but likely interferes during early embryonic and fetal development.

Animals↗
PubMed1988

Subcellular distribution of disaturated phosphatidylcholine in developing rabbit lung.

To determine the subcellular distribution of disaturated phosphatidylcholine (DSPC) in lung tissue during perinatal development, fetal rabbits at 24, 26, 28 and 31 (term) days gestation and newborns were studied. Following alveolar lavage, fractions enriched in nuclei-cellular debris, mitochondria, microsomes, surfactant (lamellar bodies) and cytosol were prepared from the residual tissue homogenate, and their DSPC content was determined. The DSPC content of the unfractionated residual lung tissue homogenate progressively and significantly increased during fetal development, rising from 9.09 +/- 0.91 to 17.45 +/- 2.88 mg/g dry lung between 24 days gestation, and term. Between 24 and 26 days gestation the overall increase in tissue DSPC was due to a two-fold increase in the mitochondrial, microsomal and cytosolic pools. Lamellar bodies were first isolable at 26 days gestation. The DSPC content of this fraction increased six-fold (from 0.10 +/- 0.02 to 0.67 +/- 0.15 mg/g dry lung) between 26 and 28 days gestation and a further seven-fold (to 4.63 +/- 1.06 mg/g dry lung) by term, accounting for the overall increase in the tissue homogenate value during this time period. By the first postnatal day, microsomal and cytosolic DSPC increased another two-fold, but no significant change occurred in the other subcellular fractions. Alveolar lavage DSPC progressively increased over the time period studied. While there was no change in the lamellar body DSPC/total PC ratio during fetal development, each of the mitochondrial, microsomal and cytosolic ratios decreased between days 26 and 28 of gestation and then increased at term.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Macrophages in the murine pancreas and their involvement in fetal endocrine development in vitro.

Macrophages are a heterogeneous population of cells that belong to the mononuclear phagocyte system. They play an important role in tissue homeostasis and remodeling and are also potent immune regulators. Pancreatic macrophages are critically involved in the development and pathogenesis of autoimmune diabetes. To elucidate the ontogeny of pancreatic macrophages, we characterized in this study the macrophages present in the adult and developing fetal pancreas of normal mice. We additionally examined the presence of local macrophage precursors and the involvement of macrophages in the growth of endocrine tissue in the fetal pancreas. We identified two phenotypically distinct macrophage subsets in the adult pancreas. The majority of macrophages was CD45(+)ER-MP23(+)MOMA-1(+). Under noninflammatory conditions, only a minority ( approximately 5%) of the pancreatic macrophages additionally expressed the macrophage marker F4/80. In contrast, in the fetal pancreas, phenotypically, mature macrophages were identified exclusively by their expression of F4/80 and lacked detectable staining with ER-MP23 and MOMA-1 antibodies. In fetal pancreas organ cultures, we could show that macrophages develop from pre-existing precursors, which are present in the fetal pancreas at embryonic age 12.5. Moreover, the number of macrophages increased significantly when macrophage-colony stimulating factor was added to these cultures. It is important that this increase of F4/80-positive cells was paralleled by an increase in the number of insulin-producing cells, suggesting that macrophages support the growth of these endocrine cells.

Animals↗
PubMed2006

T cells developing in fetal thymus of T-cell receptor alpha-chain transgenic mice colonize gammadelta T-cell-specific epithelial niches but lack long-term reconstituting potential.

The gammadelta T cells generated during mouse fetal development are absolutely dependent on their invariant T-cell receptors (TCRs) for their function. However, there is little information on whether the epithelial homing properties of fetal T cells might also be developmentally induced by factors unrelated to TCR specificity. We have previously described TCR alpha-chain transgenic (2B4 TCR-alpha TG) mice, in which the transgenic TCR alpha-chain is expressed early, already at embryonic day 14 (E14). These mice have a large population of 'gammadelta T-cell-like' CD4- CD8- (double-negative; DN) alphabeta T cells, some of which develop during E14-E18 contemporarily to intraepithelial lymphocytes (IELs) expressing invariant TCR-gammadelta. Using the 2B4 TCR-alpha TG mouse model we have been able to more precisely study the impact of a variant TCR expression on IEL development and homing. In this study we show that TCR-alpha TG and TCR-alpha TG crossed to TCR-delta-deficient mice (TCR-alpha TG x TCR-delta-/-) carry TG TCR-alpha+ dendritic epidermal T cells (DETCs) and TCR-alpha TG+ IELs in the small intestine. The TG+ DETCs develop and seed the epidermis with similar kinetics as Vgamma5+ DETCs of normal mice, in contrast to the TCR-alphabeta+ DETCs found in TCR-delta-/- mice. However, whereas the intestinal TCR-alpha TG+ IELs persist in old mice (> 20 months), the TCR-alpha TG+ DETCs do not. The data in this study indicate that the timing of TCR expression and thereby development during ontogeny regulates the specific homing potential for fetal T cells but not their subsequent functions and properties.

Aging↗
PubMedDate not supplied

Development of fetal sheep pancreas after transplantation into athymic mice.

The capacity of the fetal sheep pancreas to grow and function when transplanted into athymic mice was examined to determine whether this source of tissue might be of potential use in reversing diabetes. For this purpose fetal sheep pancreases were obtained in the period between 50 days of gestation and fullterm (148 days). Explants (1 mm3) in organ culture secreted insulin for at least 7 days, but in steadily diminishing amounts. Acute exposure to arginine (10 mM) and theophylline (10 mM), but not glucose (20 mM), calcium chloride (10 mM), and sodium butyrate (10 mM), caused acute secretion of insulin. Explants survived for many months when grafted beneath the renal capsule of athymic mice, but their growth was less, the epithelial-like component smaller, and the percentage of endocrine cells (31 +/- 5%) fewer than the case of transplanted fetal human pancreas. The beta cell was the predominant endocrine cell in the ungrafted fetal sheep pancreas. In the transplanted fetal sheep pancreas this was not so, the alpha and PP cells being dominant--beta:alpha:delta:PP = 3:14:3:11. This pattern was unchanged when the recipient mice were hyperglycaemic--beta:alpha:delta:PP = 4:13:4:28, with no reduction of blood glucose levels being observed for up to 4 mo after transplantation. Altering the site of transplantation to the spleen or liver did not improve survival of the endocrine cells. Fetal sheep pancreatic explants when transplanted into athymic rats failed to survive. Thus, although the unusual pattern of endocrine differentiation in fetal sheep pancreas transplanted into athymic mice makes it an interesting model for further studies of fetal development, it is not of benefit in normalizing the blood glucose levels of the recipients.

Animals↗
PubMed1979

Effect of nicotine on the development of fetal and suckling rats.

Nicotine, administered at a dose of 100 micrograms/kg/day from day 14 of gestation, did not affect maternal food intake, weight gain, length of gestation, litter size or fetal development; however, a daily dose of 1 mg/kg led to smaller litter size and higher incidence of stillbirth. Continued maternal administration of nicotine (100 micrograms/kg/day) until 12 days post partum did not affect newborn growth (body weight and length and size of heart and lung) during the first week after birth; during the second week, however, the nicotine-treated group lagged behind the controls. The stomachs of pups of nicotine-treated rats contained less food than those of controls; this difference increased with age, becoming more than 40% at 12 days. We suggest that lower milk production of nicotine-treated rats interferes with the normal development of the offspring during periods of rapid growth.

Animals↗
PubMed1987

Water-soluble and insoluble crystallins of the developing human fetal lens, analyzed by agarose/polyacrylamide thin-layer isoelectric focusing.

Eight human fetal lenses, selected on basis of normality, of a gestational age of 119 to 231 days were analyzed by thin-layer isoelectric focusing (IEF) in agarose/polyacrylamide gels. This method was adapted for the separation of lens crystallins into HM-, alpha-, beta- and gamma-crystallins. It is especially suitable for analysis under non-denaturing conditions of high-molecular-weight crystallins and of insoluble crystallins (WI) solubilized in formamide. The latter could be separated into HM-, alpha- and gamma-crystallins. During fetal development, a considerable increase of gamma-crystallin proportion was observed due to new synthesis. This increase was balanced by a decrease of alpha-crystallin proportion.

Acrylic Resins↗