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PubMed1981

Immunohistochemical characterization of renin-containing cells in the human juxtaglomerular apparatus during embryonal and fetal development.

Thirty kidneys from nine embryos, 20 fetuses, and one full-term baby were examined for their renin content by immunofluorescence and the peroxidase antiperoxidase method, using an antihuman renin antiserum. Renin-containing cells were found in the early metanephros (5-week-old fetuses). Most of them were located in the wall of well-developed renal arteries in the vicinity of the prospective vascular pole of the glomeruli. In the poorly differentiated peripheral renal cortex, intracellular fluorescence was seen in nearby arterioles of pocket-like s-shaped tubules. Rarely, labeled cells were found in the wall of major branches of renal arteries. In all locations, the renin-containing cells appear to be clearly linked to the development of the renal vascular system.

Cell Differentiation↗
PubMed1980

Embryonal and fetal development of capillaries: microangiographic investigations. I. The brain stem.

The prenatal development of the intracerebral capillaries within the brain stem was systematically examined by a special microangiographic technique in 69 embryos and fetuses of cattle and pigs between 4 and 17 weeks of gestation. The microradiograms were compared with the corresponding histological slices. The different developmental stages and morphological patterns of vascularization are related to the local stage of maturation, histological structure and metabolic activity of the nervous tissue.

Angiography↗
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↗
PubMed2005

Spatial and temporal localization during embryonic and fetal human development of the transcription factor SIM2 in brain regions altered in Down syndrome.

Human SIM2 is the ortholog of Drosophila single-minded (sim), a master regulator of neurogenesis and transcriptional factor controlling midline cell fate determination. We previously localized SIM2 in a chromosome 21 critical region for Down syndrome (DS). Here, we studied SIM2 gene using a new approach to provide insights in understanding of its potential role in human development. For the first time, we showed SIM2 spatial and temporal expression pattern during human central nervous system (CNS) development, from embryonic to fetal stages. Additional investigations were performed using a new optic microscopy technology to compare signal intensity and cell density [M. Rachidi, C. Lopes, S. Gassanova, P.M. Sinet, M. Vekemans, T. Attie, A.L. Delezoide, J.M. Delabar, Regional and cellular specificity of the expression of TPRD, the tetratricopeptide Down syndrome gene, during human embryonic development, Mech. Dev. 93 (2000) 189--193]. In embryonic stages, SIM2 was identified predominantly in restricted regions of CNS, in ventral part of D1/D2 diencephalic neuroepithelium, along the neural tube and in a few cell subsets of dorsal root ganglia. In fetal stages, SIM2 showed differential expression in pyramidal and granular cell layers of hippocampal formation, in cortical cells and in cerebellar external granular and Purkinje cell layers. SIM2 expression in embryonic and fetal brain could suggest a potential role in human CNS development, in agreement with Drosophila and mouse Sim mutant phenotypes and with the conservation of the Sim function in CNS development from Drosophila to Human. SIM2 expression in human fetal brain regions, which correspond to key structures for cognitive processes, correlates well with the behavioral phenotypes of Drosophila Sim mutants and transgenic mice overexpressing Sim2. In addition, SIM2-expressing brain regions correspond to the altered structures in DS patients. All together, these findings suggest a potential role of SIM2 in CNS development and indicate that SIM2 overexpression could participate to the pathogenesis of mental retardation in Down syndrome patients.

Basic Helix-Loop-Helix Proteins↗
PubMed1992

Skeletal muscle satellite cells appear during late chicken embryogenesis.

The emergence of avian satellite cells during development has been studied using markers that distinguish adult from fetal cells. Previous studies by us have shown that myogenic cultures from fetal (Embryonic Day 10) and adult 12-16 weeks) chicken pectoralis muscle (PM) each regulate expression of the embryonic isoform of fast myosin heavy chain (MHC) differently. In fetal cultures, embryonic MHC is coexpressed with a ventricular MHC in both myocytes (differentiated myoblasts) and myotubes. In contrast, myocytes and newly formed myotubes in adult cultures express ventricular but not embryonic MHC. In the current study, the appearance of myocytes and myotubes which express ventricular but not embryonic MHC was used to determine when adult myoblasts first emerge during avian development. By examining patterns of MHC expression in mass and clonal cultures prepared from embryonic and posthatch chicken skeletal muscle using double-label immunofluorescence with isoform-specific monoclonal antibodies, we show that a significant number of myocytes and myotubes which stain for ventricular but not embryonic MHC are first seen in cultures derived from PM during fetal development (Embryonic Day 18) and comprise the majority, if not all, of the myoblasts present at hatching and beyond. These results suggest that adult type myoblasts become dominant in late embryogenesis. We also show that satellite cell cultures derived from adult slow muscle give results similar to those of cultures derived from adult fast muscle. Cultures derived from Embryonic Day 10 hindlimb form myocytes and myotubes that coexpress ventricular and embryonic MHCs in a manner similar to cells of the Embryonic Day 10 PM. Thus, adult and fetal expression patterns of ventricular and embryonic MHCs are correlated with developmental age but not muscle fiber type.

Animals↗
PubMed1991

Solitary neuroendocrine cells and neuroepithelial bodies in the lower airways of embryonic, fetal, and postnatal sheep.

The sheep pulmonary intraepithelial APUD system was studied by histochemical, immunocytochemical, and electron microscopy techniques during different periods of lung development: embryonic, fetal (pseudoglandular, canalicular, and alveolar), and postnatal. The cells of the ovine pulmonary intraepithelial APUD system were found randomly distributed throughout the conducting and respiratory or undifferentiated airways. They appeared as isolated cells (solitary neuroendocrine cells) or in groups (neuroepithelial bodies). These cells were argyrophilic and immunoreactive for neuron-specific enolase but were not argentaffin. Ultrastructurally they were characterized by a basal position in the respiratory epithelium and by the presence of neurosecretory granules (dense-core vesicles) ranging between 65 and 230 nm of diametre. Quantitative studies showed that single neuroendocrine cells were more numerous in distal conducting airways and at fetal stages. The earliest identifiable argyrophilic and NSE-immunoreactive neuroendocrine cells in sheep airways appeared at gestational week 5, close to the term of the embryonic period.

APUD Cells↗
PubMed1993

Administration of melanotropic peptides during gestation in the rodent.

A potent analogue of alpha-MSH (alpha-melanocyte stimulating hormone, S-alpha-melanotropin), [Nle4,D-Phe7] alpha-MSH, induces darkening of follicular melanocytes when injected or applied topically to the skin of mice [1]. This analogue also results in increased pigmentation when injected subcutaneously (s.c.) in humans. Toxicological studies have been performed on rodent models with administration topically or by intraperitoneal (i.p.) injection. No toxicity was observed and no pathological or significant biochemical changes were found. However there has been some controversy in the literature revolving around whether or not alpha-MSH is trophic for fetal growth and whether the hormone affects fetal adrenal development. These questions have been addressed in this study. All previous studies on the possible reproductive function of alpha-MSH have involved use of the natural hormone only. This is first to demonstrate the effects of the more potent analogue. The rat was used as the animal model to determine if the potent analogue of alpha-MSH affects events in gestation and embryonic fetal development and to determine if the analogue was a developmental toxicant. This study also examines the effect of a melanotropic peptide delivered directly to the conceptus in utero during organogenesis. No changes were found in the parameters examined (sex ratio, weight, morphology or histology, etc.) between treated and control fetuses. There was no evidence of premature parturition or pigmentation changes in the fetuses. The work reported in this study is of relevance if such a melanotropic peptide is to be used in women of childbearing age to induce pigmentation of the skin. Although the present results cannot necessarily be extrapolated to humans, indications are that, in rodents at least, [Nle4,D-Phe7] alpha-MSH and natural alpha-MSH have no adverse effects when administered during gestation and fetal development.

Animals↗
PubMed2004

Post hatching development: a novel system for extended in vitro culture of bovine embryos.

Although acceptable rates of blastocyst formation are achieved with in vitro production of bovine embryos, several problems still compromise the subsequent development of the fetus and newborn, especially in embryos originating from somatic cell nuclear transfer. Routinely, the potential development of a bovine conceptus is predicted either on blastocyst quality or on various parameters related to the embryonic-fetal development in a foster mother. These methods are either imprecise or costly, highlighting the need for more reliable and practical methods to evaluate early embryonic development and differentiation. Thus, our aim was to improve the in vitro culture of embryos post hatching and to define a stable and repeatable system to monitor the development of bovine embryos. For that, in vitro-derived embryos were cultured in agarose gel tunnels in a modified culture medium (SOFaaci within 10% fetal bovine serum and 27.7 mM glucose). Daily monitoring of embryo length revealed that 56%-67% of the embryos in culture showed rapid growth and elongated until Day 13. Electron microscopy of elongated embryos at Day 14 confirmed successful localization of differentiated cells forming the trophoblast and hypoblast, with the definition of the Rauber layer. In conclusion, a stable culture system of post hatching embryos was first defined and can be used as a model for rapid growth, elongation, and initial differentiation of bovine post hatching embryos produced entirely in vitro.

Animals↗
PubMedDate not supplied

Lack of adverse effects on fertility of female CD-1 mice exposed to repetitive intravaginal gel-microemulsion formulation of a dual-function anti-HIV agent: aryl phosphate derivative of bromo-methoxy-zidovudine (compound WHI-07).

5-bromo-6-methoxy-5,6-dihydro-3(')-azidothymidine-5(')-(p-bromophenyl) methoxyalaninyl phosphate (WHI-07), a novel bromo-methoxy-substituted aryl phosphate derivative of zidovudine (ZDV), is a potent dual-function contraceptive agent with anti-HIV activity. Its potential for reproductive toxicity was assessed in a series of experiments using CD-1 mice under the conditions of its intended use as an intravaginal microbicide. Female CD-1 mice were exposed intravaginally to a gel-microemulsion formulation containing 0%, 0.5%, 1.0% or 2.0% WHI-07 for up to 13 weeks. On a molar basis, these concentrations represent 1400-5700 times its in vitro spermicidal IC(50) and 1.4-5.7(x10(6)) times its in vitro anti-HIV IC(50). We examined the effects of intravaginally administered WHI-07 on: ovulation efficiency; in vivo fertilization and early embryonic, fetal development; and reproductive outcome, including neonatal survival and pup development. Compound WHI-07 was administered intravaginally during superovulation, organogenesis and prior to mating for 5 and 10 consecutive days and for 13 weeks, respectively. Mice were evaluated for ovulation efficiency and fertilization rate and cleavage 14 and 40 h after human chorionic gonadotropin (hCG) injection, respectively. Pregnant mice were administered 2% WHI-07 intravaginally during gestation days (GD) 6-15 and measures of teratogenicity were evaluated on GD 17. For short-term toxicity study, mice were given intravaginal treatment of gel-microemulsion containing 0%, 0.5%, 1.0% and 2.0% WHI-07 for 13 weeks and then mated with untreated males to evaluate potential reproductive and developmental effects. Repeated intravaginal exposure of mice to 2% WHI-07 had no adverse effects on ovulation response, mean number of eggs recovered or the percentage of eggs fertilized or cleaved. No evidence of reproductive toxicity, fetal toxicity or teratogenicity was found following repetitive intravaginal application of 2% WHI-07 during the period of organogenesis. Furthermore, repeated intravaginal exposure of mice to 0.5-2.0% WHI-07 for 13 weeks had no adverse effect on the subsequent reproductive capability, perinatal outcome or growth and development of the offspring. Compound WHI-07 shows unique clinical potential as a safe, dual-function vaginal contraceptive for curbing mucosal and perinatal HIV transmission.

Administration, Intravaginal↗
PubMed1994

The evolution of the chicken sarcomeric myosin heavy chain multigene family.

This manuscript describes the chicken sarcomeric myosin heavy chain (MyHC) multigene family and how it differs from the sarcomeric MyHC multigene families of other vertebrates. Data is discussed that suggests the chicken fast MyHC multigene family has undergone recent expansion subsequent to the divergence of avians and mammals, and has been subjected to multiple gene conversion-like events. Similar to human and rodent MyHC multigene families, the chicken multigene family contains sarcomeric MyHC genes that are differentially regulated in developing embryonic, fetal, and neonatal muscles. However, unlike mammalian genes, chicken fast MyHC genes expressed in developing muscles are also expressed in mature muscle fibers as well. The potential significance of conserved and divergent sequences with the MyHC rod domain of five fast chicken isoforms that have been cloned and sequenced is also discussed.

Animals↗
PubMed1986

Cell surface carbohydrate changes during embryonic and fetal skin development.

Monoclonal antibodies to four type 2 chain carbohydrate antigens were used for immunohistochemical studies of embryonic and fetal skin. The antibodies detected N-acetyllactosamine and 3 fucosyl substitutes of this, blood group antigen H, Lex, and Ley. Periderm consistently stained for N-acetyllactosamine, Lex and Ley. The H antigen showed a variable and weak expression on peridermal cells from day 57 to day 84 estimated gestation age (EGA). After this period the H antigen was no longer expressed at peridermal cells. In the epidermis, N-acetyllactosamine was present on all cells until the age of 15 weeks EGA. After this period N-acetyllactosamine could only be demonstrated on basal cells after treatment with neuraminidase, indicating a masking of N-acetyllactosamine by sialic acid. The H antigen could not be demonstrated in the epithelium before 14 weeks EGA. At this time it appeared on spinous and granular cells in the epithelium. Lex stained both basal cells and intermediate cells positively, until keratinization around week 20 EGA. Ley is never expressed on basal cells. It is weakly expressed by intermediate cells from week 14 EGA. Our study demonstrates that N-acetyllactosamine is maximally expressed at the early stages of development, but may later be modified either by sialylation or fucosylation into blood group H or Lex, or by Ley substances, respectively. The orderly and well-defined changes observed during skin differentiation are in agreement with other studies, which have demonstrated the existence of chemically defined cell surface changes accompanying cell differentiation.

ABO Blood-Group System↗