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PubMed1988

Polyamines and enzymes of polyamines metabolism in the cartilage during embryonic development.

1. In chicken embryo cartilage putrescine levels, maximal at day 8, fall by day 16 to a four-fold lower value, which remains unchanged through hatching and in the 12-day-old chick. 2. Spermine and spermidine, initially higher than putrescine, are almost halved between days 8 and 11, and remain constant afterwards. 3. Ornithine decarboxylase is down to 20% of the day 8 value by day 16, and is further reduced in the newly hatched chick. 4. S-Adenosyl-methionine decarboxylase activity shows a 50% reduction between days 8 and 11, and no further changes. 5. Spermidine acetyltransferase activity at day 11 is 30% lower than at day 8, goes back up to the initial level by day 16, and progressively decreases through hatching and the first 12 days of life.

Acetyltransferases↗
PubMed1990

Autologous immune complex glomerulonephritis induces abnormal embryonic development.

Young female random-bred Wistar rats were immunized with homologous renal brush border membranes. The immunized animals exhibited all the clinical and immunopathological characteristics of chronic autologous immune complex glomerulonephritis (Heymann nephritis) closely resembling the idiopathic membranous glomerulonephritis in humans. The animals were subsequently mated. Congenital malformations and fetal growth retardation were observed in the offspring of the nephritic mothers; high incidence of embryonic/fetal resorptions was also observed. The types of anomalies were microphthalmia, cataractic lens, abnormal retina, micrognathia, cleft palate, lordosis, fetal edema, variable hemorrhage, omphalocele, syndactaly and cryptochidism. The most frequently observed anomaly was associated with the eye. Immunofluorescent studies indicated that no rat IgG was detected in the extraembryonic membranes, embryo or fetuses. Rat complement C3 was also absent around the conceptuses. The pathophysiologic mechanism leading to such deleterious embryonic/fetal effect is not clear.

Animals↗
PubMed1990

[Clinical study results of the embryonic development in gilts and brooding performance of gilts and sows after HCG treatment on the 11th day of pregnancy].

Forty-four pregnant gilts were slaughtered on the 32nd and 33rd days of pregnancy, after 30 of them had received 100 or 400 IU of HCG on the eleventh day of pregnancy. Both doses had resulted in higher number of living embryos. Embryo survival rates of treated sows were up to 14.9 percent higher than those of untreated animals. Higher numbers of embryos had no adverse effect on their mass development. Fertility was measured of 77 HCG-treated and untreated gilts as well as of 54 adult sows. The number of non-pregnant sows which returned to oestrus was higher in the group of gilts and adult sows which had received treatment. The number of pregnant animals in the treated adult sow group was seven percent higher than that in the control group. Increased litter sizes were additionally recordable from those gilts and adult sows that had received HCG injections. Yet, those higher litter sizes were associated with lower weight of live-born piglets. In further studies more attention should be given to possible stimulation of LH secretion in early gravidity.

Animals↗
PubMed2003

Effects of PKC activation on the meiotic maturation, fertilization and early embryonic development of mouse oocytes.

Protein kinase C (PKC) is a family of Ser/Thr protein kinase widely distributed in eukaryotes. There is evidence that PKC plays key roles in the meiotic maturation and activation of mammalian oocytes. However, the mechanism of PKC's actions and the PKC isoforms responsible for these actions are poorly understood. In this study, we reveal in mouse eggs and early embryos: (1) the effects of PKC on the meiotic and mitotic cell cycle progression during oocyte maturation, egg activation and embryonic cleavages; (2) the functional importance of classical PKC subclasses in these processes; and (3) the subcellular localization of the PKC alpha isoform during development from GV stage oocytes to the blastocyst stage embryos. The results indicate that the PKC activator phorbol 12-myristate 13-acetate (PMA) inhibits the meiotic resumption of cumulus-free mouse oocytes by a mechanism dependent not only on classical PKC activity but also on other PKC isoforms. PKC activation after germinal vesicle breakdown leads to the inhibition of mitogen-activated protein kinase phosphorylation and the arrest of cell cycle at MI stage. The second polar body emission and the cleavages of early embryos are blocked after prolonged PKC activation. The subcellular localization of PKC alpha isoform in mouse oocytes and embryos is developmental-stage associated. All these results suggest that PKC has multiple functional roles in the cell cycle progression of mouse oocytes and embryos.

Animals↗
PubMed1994

Hepatocyte growth factor (HGF/SF) is expressed in human epithelial cells during embryonic development; studies by in situ hybridisation and northern blot analysis.

This study reports the tissue distribution of Hepatocyte Growth Factor-Scatter Factor (HGF/SF) in human fetal tissue using Northern analysis and in situ hybridisation techniques. In tissue from fetuses of 9-17 wk gestational age, the 6 kb mRNA transcript for HGF/SF was demonstrated in many tissues but prominently in liver, intestine, gall bladder and spleen. In situ hybridisation demonstrated that HGF/SF expression was not confined to mesenchymal tissues, as suggested by previous studies but was expressed in epithelial tissues, particularly in small intestine, keratinising epithelium of tongue, skin and oesophagus. In the small intestine epithelial expression was strikingly regional, being confined to the crypt region, the site of enterocyte proliferation. Northern analysis of tissues for c-met mRNA, representing expression of the HGF/SF receptor, demonstrated receptor expression in all tissues studied except the thyroid gland.

Blotting, Northern↗
PubMed2000

Role of transforming growth factor-alpha and the epidermal growth factor receptor in embryonic rat testis development.

Embryonic testis development requires the morphogenesis of cords and growth of all cell populations to allow organ formation. It is anticipated that coordination of the growth and differentiation of various cell types involves locally produced growth factors. The current study was an investigation of the hypothesis that transforming growth factor-alpha (TGF-alpha) is involved in regulating embryonic testis growth. TGF-alpha has previously been shown to function in the postnatal testis. TGF-alpha and other members of the epidermal growth factor (EGF) family act through the epidermal growth factor receptor (EGFR) to stimulate cell proliferation and tissue morphogenesis. To understand the potential actions of TGF-alpha in the embryonic testis, general cell proliferation was investigated. Characterization of cell proliferation in the rat testis throughout embryonic and postnatal development indicated that each cell type has a distinct pattern of proliferation. Germ cell growth was transiently suppressed around birth. Interstitial cell growth was high embryonically and decreased to low levels around birth. A low level of Sertoli cell proliferation was observed at the onset of testis cord formation. Sertoli cell proliferation in early embryonic development was low; the levels were high later in embryonic development and remained high until the onset of puberty. Both TGF-alpha and the EGFR were shown to be expressed in the embryonic and postnatal rat and mouse testis. Perturbation of TGF-alpha function using neutralizing antibodies to TGF-alpha on testis organ cultures dramatically inhibited the growth of both embryonic and neonatal testis. TGF-alpha antibodies had no effect on cord formation. The TGF-alpha antibody was found to be specific for TGF-alpha in Western blots when compared to EGF and heregulin. Testis growth was also inhibited by perturbation of EGFR signaling using an EGFR kinase inhibitor. Therefore, TGF-alpha appears to influence embryonic testis growth but not morphogenesis (i.e., cord formation). Treatment of embryonic testis organ cultures with exogenous TGF-alpha also perturbed development, leading to an increased proliferation of unorganized cells. Testis from EGFR and TGF-alpha knockout mice were analyzed for testis morphology. TGF-alpha knockout mice had no alterations in testis phenotype, while EGFR knockout mice had a transient decrease in the relative amount of interstitial cells before birth. Observations suggest that there may be alternate or compensatory factors that allow testis growth to occur in the apparent absence of TGF-alpha actions in the mutant mice. In summary, the results obtained suggest that TGF-alpha is an important factor in the regulation of embryonic testis growth, but other factors will also be involved in the process.

Animals↗
PubMed1997

The solid state environment orchestrates embryonic development and tissue remodeling.

Cell interactions with extracellular matrix and with other cells play critical roles in morphogenesis during development and in tissue homeostasis and remodeling throughout life. Extracellular matrix is information-rich, not only because it is comprised of multifunctional structural ligands for cell surface adhesion receptors, but also because it contains peptide signaling factors, and proteinases and their inhibitors. The functions of these groups of molecules are extensively interrelated. In this review, three primary cell culture models are described that focus on adhesion receptors and their roles in complex aspects of morphogenesis and remodeling: the regulation of proteinase expression by fibronectin and integrins in synovial fibroblasts; the regulation of osteoblast differentiation and survival by fibronectin, and the regulation of trophoblast differentiation and invasion by integrins, cadherins and immunoglobulin family adhesion receptors.

Animals↗
PubMed1978

Embryonic development in consecutive specimens from recurrent spontaneous abortions.

Although habitual abortion occurs in a relatively small number of patients, its successful management is often difficult. Etiologic factors may be either maternal or embryonic or both; there is much information available on maternal factors but little is known of factors related to the embryo. Information obtained from examining and karyotyping the aborted embryo or fetus may be of considerable importance in determining the possible cause of the abortion and subsequent investigation and counseling of the patient. At least two specimens from over 50 women who have had two or more consecutive spontaneous abortions have been examined and the results show that: (1) Patients aborted conceptuses of the same developmental stage, i.e., embryo or fetus, in consecutive pregnancies. This suggests that investigation should be directed to factors which may be important in the stage of pregnancy indicated. (2) Late abortions were associated with normal fetal development and factors related to the uterine environment. (3) The conceptus in an early abortion was significantly more likely to have a cytogenetic abnormality, suggesting a problem at, or prior to, conception/fertilization. A case study is also included.

Abortion, Habitual↗
PubMed1995

Murine Wnt-11 and Wnt-12 have temporally and spatially restricted expression patterns during embryonic development.

The Wnt gene family encodes a set of signalling molecules implicated in the development of a wide range of organisms. We have recently cloned partial cDNA sequences of murine Wnt-11 and Wnt-12. Here, we describe the spatio-temporal expression patterns of both genes during mouse embryogenesis. Wnt-11 expression is first detected within the truncus arteriosus from 8.25 dpc. By 9.5 dpc, Wnt-11 expression is detected in the somites at the medial junction of the dermatome and the myotome. Wnt-11 transcripts are also detected in limb bud mesenchyme from the time the bud is first visible. Wnt-12 is detected in the apical ectodermal ridge from 10.5 dpc. The implications of these expression patterns are discussed.

Amino Acid Sequence↗
PubMedDate not supplied

Fertilization, embryonic development and pregnancy losses with intracytoplasmic sperm injection for surgically-retrieved spermatozoa.

Prior to the development of intracytoplasmic sperm injection (ICSI), azoospermic and severely oligozoospermic men had little to no chance of having a biological child. In this study, ICSI outcome in 454 transfers with ejaculated spermatozoa and 59 transfers with surgically retrieved spermatozoa were evaluated. Normal fertilization rate using ejaculated spermatozoa was 75% of 5995 oocytes, and 73% of 751 oocytes for surgically retrieved spermatozoa; with ongoing pregnancy rates of 53% (242/454) and 61% (36/59) respectively. Surgically retrieved spermatozoa significantly (P < 0.05) impacted 1PN oocytes (6.1%, 46/751), severely fragmented embryos (8.8%, 46/550) and incidence of pregnancy loss (11%, 4/36). When using ejaculated spermatozoa, incidence of 1PN oocytes, severely fragmented embryos and pregnancy loss was 2.9% (177/5995), 4.5% (200/4365), 2.4% (6/242) respectively.

Abortion, Spontaneous↗
PubMed1993

Effect of bredinin on early embryonic development in mice.

Bredinin, an immunosuppressive agent, had a teratogenic effect and a decreasing effect in litter size in mice and in rats. We investigated the direct effect of bredinin on the development of mouse preimplantation embryos in vitro. Bredinin strongly inhibited the first differentiation step from the morula to the blastocyst stage, whereas the steps from the two-cell embryo to the morula stage were not inhibited. At 10(-6) or 10(-5) M of bredinin, only one or none of the morula embryos developed to a blastocyst after a 48 h culture; while approximately 90% of the embryos developed to blastocysts in the absence of bredinin. To determine whether the bredinin inhibition was reversible, the morula embryos were cultured with 10(-5) M of bredinin for 48 h. The embryos were transferred to bredinin-free culture conditions, and their development was observed. The inhibitory effect of bredinin was reversible. The expansion of zona-free blastocyst was also inhibited by bredinin. When blastocyst embryos were cultured in the presence of bredinin (10(-6) M), the mean size of the embryos was reduced to half the initial size. In addition, the steps of hatching from the zona pellucida and attaching to the substratum were significantly inhibited by bredinin. Trophoblast outgrowth was completely inhibited by 10(-6) M bredinin; however, the area of trophoblast outgrowth was expanded to 18-fold the initial size after a 96 h culture in the absence of bredinin. Thus, the decrease in the number of offspring is due to the direct effect of bredinin on mice embryos.

Animals↗
PubMed2001

The copper transporter CTR1 provides an essential function in mammalian embryonic development.

Copper serves as an essential cofactor for a variety of proteins in all living organisms. Previously, we described a human gene (CTR1;SLC31A1) that encodes a high-affinity copper-uptake protein and hypothesized that this protein is required for copper delivery to mammalian cells. Here, we test this hypothesis by inactivating the Ctr1 gene in mice by targeted mutagenesis. We observe early embryonic lethality in homozygous mutant embryos and a deficiency in copper uptake in the brains of heterozygous animals. Ctr1(-/-) embryos can be recovered at E8.5 but are severely developmentally retarded and morphologically abnormal. Histological analysis reveals discontinuities and variable thickness in the basement membrane of the embryonic region and an imperfect Reichert's membrane, features that are likely due to lack of activity in the collagen cross-linking cupro-enzyme lysyl oxidase. A collapsed embryonic cavity, the absence of an allantois, retarded mesodermal migration, and increased cell death are also apparent. In the brains of heterozygous adult mice, which at 16 months are phenotypically normal, copper is reduced to approximately half compared with control littermates, implicating CTR1 as the required port for copper entry into at least this organ. A study of the spatial and temporal expression pattern of Ctr1 during mouse development and adulthood further shows that CTR1 is ubiquitously transcribed with highest expression observed in the specialized epithelia of the choroid plexus and renal tubules and in connective tissues of the eye, ovary, and testes. We conclude that CTR1 is the primary avenue for copper uptake in mammalian cells.

Animals↗
PubMed1997

Azoospermic men with deletion of the DAZ gene cluster are capable of completing spermatogenesis: fertilization, normal embryonic development and pregnancy occur when retrieved testicular spermatozoa are used for intracytoplasmic sperm injection.

Some men with non-obstructive azoospermia harbour fully formed spermatozoa within their testicular tissue that can be used to achieve pregnancy via intracytoplasmic sperm injection (ICSI). Recently, Reijo et al. (1995) provided compelling evidence that the DAZ gene cluster is a strong candidate for one of the elusive azoospermia factors (AZF) located on the long arm of the Y chromosome. The DAZ gene cluster is deleted in 13% of azoospermic men and a small percentage of severely oligozoospermic men. Vertical transmission from father to son of AZF region deletions has also been described. Presumably these fathers were oligozoospermic. This led us to ask whether the azoospermic male with deletions of the AZF/DAZ region can also complete minimal spermatogenesis and whether any spermatozoa found could participate in fertilization, embryo development and pregnancy. Three out of six (50%) of the azoospermic men with AZF/DAZ deletions had spermatozoa identified within their harvested testicular tissue. When these spermatozoa were used for ICSI, fertilization occurred in 36% of injected oocytes. This compared favourably with testicular spermatozoa retrieved from non-obstructive azoospermic men without AZF/DAZ gene deletions. In one case, a twin conception resulted, which represents the first term pregnancy reported using spermatozoa from an AZF/DAZ deleted azoospermic male. Therefore it is necessary to take the possibility of transmission of infertility or sterility to our patients' offspring seriously when utilizing today's reproductive technologies, as spermatogenesis in men with AZF/DAZ deletions is by no means an exceptional occurrence.

Chromosome Mapping↗
PubMed1989

Effect of trypsin in semen on in vivo fertilization and early embryonic development in superovulated heifers.

The effect of trypsin on the fertilizing capacity of bull semen was investigated as part of the evaluation of the addition of trypsin to semen as a method for destroying or inactivating infectious agents. Parts of the ejaculates from four bulls were treated with 0.3% trypsin solution. Both the treated and untreated aliquots of semen were frozen, thawed and used for the artificial insemination of superovulated heifers. Two hundred and thirty ova and embryos were collected from 22 heifers on day 7 after oestrus (insemination). One hundred and ten out of 164 (67%) embryos and ova from 15 heifers inseminated with trypsin-treated semen were classified as of transferable quality compared to 46 out of 66 (70%) in the control group of 7 heifers (p greater than 0.05). There was no difference in the proportion of fertilized ova or degenerated embryos resulting from the control or trypsin-treated samples of frozen-thawed semen, which is consistent with results obtained previously using fresh semen.

Animals↗
PubMedDate not supplied

Ontogeny of activin B and follistatin in developing embryonic mouse pancreas: implications for lineage selection.

Activin, a member of the transforming growth factor-beta superfamily, has been shown to be a critical regulator in exocrine and endocrine pancreas formation. The purpose of our study was to describe the ontogeny of activin B and its inhibitor, follistatin, in developing pancreas and to elucidate potential mechanisms for exocrine and endocrine lineage selection. Mouse embryonic pancreata were dissected at various ages (day 10 [E10.5] to birth [E18.5]), sectioned, and immunostained for activin B (one of two existing isomers, A and B), follistatin, insulin, and glucagon. In addition, reverse transcriptase-polymerase chain reaction was employed to determine the messenger RNA expression of follistatin in isolated pancreatic epithelia and mesenchyme of various ages. Activin B was first detected at E12.5 in epithelial cells coexpressing glucagon. At E16.5 these coexpressors appeared as clusters in close proximity to early ducts. By E18.5 activin B was localized to forming islets where cells coexpressed glucagon and were arranged in the mantle formation characteristic of mature alpha cells. Follistatin was found to be ubiquitous in pancreatic mesenchyme at early ages by immunohistochemical analysis, disappearing sometime after E12.5. Follistatin reappeared in E18.5 islets and remains expressed in adult islets. Follistatin messenger RNA was first detected in epithelium at E11.5, preceding its protein expression in islets later in gestation. We propose that mesenchyme-derived follistatin inhibits epithelium-derived activin at early embryonic ages allowing for unopposed exocrine differentiation and relative suppression of endocrine differentiation. At later ages the decrease in the amount of mesenchyme relative to epithelium and the subsequent drop in follistatin levels liberates epithelial activin to allow differentiation of endocrine cells to form mature islets by the time of birth.

Activins↗
PubMed1999

Stimulation of early embryonic development in cattle by coculture with surfactant.

PURPOSE: Our purpose was to determine the efficacy of Surfacten, a bovine pulmonary surfactant, on the maturation of in vitro bovine ova. METHODS: We used Surfacten as a supplement to the coculture media both at the onset of coculture and after cleavage in bovine ova had been determined. The controls received no Surfacten. RESULTS: The maturation rate in bovine embryos to the blastocyst stage statistically improved (P < 0.05) in the series in which Surfacten was added to the media at the onset of coculture, compared with the controls and the series in which Surfacten was added after cleavage had been determined. CONCLUSIONS: Surfacten, a commercially available surfactant which is a naturally occurring phospholipid that dramatically increases in the cervical mucus and the ampullaris of the oviduct at or near the time of ovulation, improves the maturation of bovine embryos in vitro by making the coculture medium approach the conditions found in the oviducts.

Animals↗
PubMed2004

Expression of the third complement component (C3) and carboxypeptidase N small subunit (CPN1) during mouse embryonic development.

Complement regulatory proteins prevent excessive complement system activation and deposition, which can lead to host tissue damage, including fetal loss during pregnancy. To further understand the regulation of complement during development, we examined the expression of the complement protein, C3, and the active subunit of carboxypeptidase N (CPN1), the complement anaphylatoxin regulator. RNA and protein analyses indicated that CPN1 expression occurred as early as 8.5 days post coitus (dpc) and continued through birth. At 10.5 and 13.5 dpc, in situ hybridization revealed CPN1 RNA in erythroid progenitor cells. At 16.5 dpc, expression of CPN1 was also detected in hepatocytes. In comparison to CPN1, C3 RNA expression occurred later (after 13.5 dpc). Moreover, C3 expression was limited to the liver erythroid progenitor cells at 16.5 dpc. These results demonstrated that mouse embryos contain RNA and protein for both C3 and CPN1, and CPN1 expression precedes that of C3 by several days.

Animals↗