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At least 631 records · Page 35Linked to original sources
PubMed1978

[Antibiotic action on the embryonic development of the fetuses of amphibians].

The effect on the embrionic development of Tr. cristatus of 16 antibiotics (keflin, penicillin, benzazillin, ampicillin, nystatin, kanamycin, streptomycin, novobiocin, brunomycin, erythran, oleandomycin, tetracyclin, chlornytromycin, gentamycin, rimactan, and capreomycin) administered in 3 concentrations was studied. It was established that except kanamycin, keflin and rimactan all the rest damage the embryonic development showing certain phase specifity. Gastrulation turned to be the most sensitive embryonic period.

Amphibians↗
PubMed1992

Studies on the biology of Argas (A.) reflexus (Fabricius, 1794) (Acari: Ixodida: Argasidae). 2. Effect of alternating temperatures on embryonic development and egg hatch.

The paper presents the results of observations on the effect of temperature alterations between 9 degrees C and 30 degrees C every 6 and 12 hours, respectively, on the embryonic development and egg hatch of Argas (A.) reflexus. No effect of the frequency of temperature changes on the percentage of egg mortality, embryo mortality, abnormal egg hatching, or egg hatching into morphologically normal larvae was observed. The experiments showed that in changes temperature have a particularly detrimental effect on the eggs prior to blastulation.

Animals↗
PubMedDate not supplied

Vibration analysis on incubating eggs and its relation to embryonic development.

Coucke (1998) was the first to use acoustic resonance analysis to monitor embryo development in chicken eggs. He remarked that at around 100 hours of incubation, the course of the resonant frequency and damping changed abruptly in the case of fertile eggs. He also showed that these changes were related to a physiologic event during early embryonic development. The objective of our study is to monitor the course of the vibration parameters during the early incubation of chicken eggs and to relate these changes to egg and embryo characteristics. A total of 72 Hybro eggs were incubated vertically in a small incubator at standard conditions. Several egg parameters were measured before incubation. During the early stages of incubation the vibration behavior of these eggs was monitored. The time at which the damping of the vibration suddenly changed, the diameter of the eggs and their interaction were found to be significant explanatory variables in order to predict hatching time. A correlation coefficient r of 0.72 was obtained.

Animals↗
PubMed1995

Common molecular pathways for patterning of the body axis, limbs, central nervous system, and face during embryonic development.

Many congenital anomalies affecting the face are known to appear as syndromes or associations, in combination with other defects. Often, these involve the limbs, eyes, central nervous system, and body axis. A general, and understandable, tendency among clinical researchers has been to seek a single cell type or definable embryologic process on which to ascribe the etiologic basis for such associations. The possibility of a gene, or group of genes, under coordinate control has not received much attention until recently. With the advent of recombinant DNA technology and the current explosion in basic research on the molecular bases of embryonic development, however, several possibilities are beginning to emerge. Here, I will list a few genes whose expression during development suggests that the molecules they encode are used as part of a coordinate molecular pathway, and that they play a role in the development of systems that often appear together in congenital associations or syndromes.

Abnormalities, Multiple↗
PubMed1977

The effect of heterologous antisera on embryonic development. XIII. Lack of effect of antisera to alpha fetoprotein.

This investigation was carried out to determine whether heterologous antisera to alpha fetoprotein (AFP) are embryotoxic to developing rat embryos. Homogeneous rat AFP was isolated and antisera directed against this glycoprotein were produced in rabbits, horse and goat. The effect of the antisera on embryonic development was examined by injecting the antisera intraperitoneally into pregnant rats on the ninth, eleventh and thirteenth days of gestation. The results demonstrated that there was no evidence of increased incidence of fetal abnormalities in 472 surviving fetuses of 42 injected rats. There was no evidence of increase embryonic death or retardation of intrauterine growth following administration of the antisera on the ninth, eleventh and thirteenth days of gestation. The localization of the injected antisera was examined by the indirect immunofluorescent method. The results showed that the heterologous AFP antibodies localized specifically in the visceral yolk sac placenta. No antibody localization was observed in the embryo proper or the chorioallantoic placenta. It is speculated that the localization of AFP antibodies in the visceral yolk sac does not interfere with the embryotrophic function of the visceral yolk sac placenta.

Animals↗
PubMed1989

Absence of a direct effect of recombinant interleukins and cultured peritoneal macrophages on early embryonic development in the mouse.

On the basis of their recent studies, several researchers have suggested that the infertility associated with mild endometriosis is due to the alteration of peritoneal fluid, resulting in impairment of the viability of gametes or embryos. Elevated numbers of macrophages and lymphocytes have been reported in the peritoneal fluid of patients with endometriosis. Interleukin-1 (IL-1) a major product of activated macrophages and Interleukin-2 (IL-2), a product of most activated T-cells, have been postulated to play a role in the infertility associated with this disease, possibly by acting as direct embryotoxic agents. We have examined the effect of purified recombinant IL-1 and IL-2, which are not species-specific, on in vitro development of mouse embryos. Both interleukins had no effect on development to the blastocyst stage or on early stages of implantation, as measured in vitro by attachment and outgrowth of blastocysts to fibronectin-coated dishes. Moreover, co-culture of mouse embryos with activated human peritoneal macrophages had no effect on embryogenesis. We conclude that neither IL-1, nor other products of human macrophages activated by lipopolysaccharide, nor IL-2 are directly toxic to early mouse embryonic development.

Animals↗
PubMed2002

Adult murine neurons: their chromatin and chromosome changes and failure to support embryonic development as revealed by nuclear transfer.

Fully differentiated neurons in adult mammalian brains do not divide; consequently, their metaphase chromosomes have never been examined. Here we report metaphase chromosome constitutions of cortical neurons in adult mice visualized by a nuclear transfer technique. We found that although some reconstructed oocytes cloned from neuronal nuclei have an apparently normal karyotype, the majority do not. Regardless of chromosome morphology, nuclei of adult neurons totally lack the ability to support embryonic development. These findings support the hypothesis that fully differentiated neurons in adult mammalian brains are genomically altered.

Animals↗
PubMed2006

Sema3D and Sema7A have distinct expression patterns in chick embryonic development.

By RT-PCR, we isolated a partial cDNA clone for the chick Semaphorin7A (Sema7A) gene. We further analyzed its expression patterns and compared them with those of the Sema3D gene, in chick embryonic development. Sema3D and Sema7A appeared to be expressed in distinct cell populations. In mesoderm-derived structures, Sema7A expression was detected in the newly formed somites, whereas Sema3D expression was found in the notochord. In ectoderm-derived tissues, Sema3D is expressed broadly in the surface ectoderm, lens and nasal placodes. Sema3D is also expressed in the developing nervous system including diencephalon, dorsal neural tube, optical and otic vesicles. In the limb bud, Sema3D expression was found throughout the ectoderm excluding the apical ectoderm ridge (AER), where Sema7A is concentrated. Although both genes appeared to be expressed in the migrating neural crest cells, Sema3D expression is limited to neural crest cells migrating out of the midbrain/hindbrain regions, while Sema7A expression is widespread in both cranial and trunk neural crest cells.

Amino Acid Sequence↗
PubMed1997

Sperm head decondensation, pronuclear formation, cleavage and embryonic development following intracytoplasmic injection of mitochondria-damaged sperm in mammals.

The objective of this study was to investigate the influence of sperm mitochondrial destruction on sperm head decondensation, male pronuclear formation, cleavage and embryonic development. In the study two models were used: heterologous (hamster ICSI assay: human sperm injected into a hamster oocyte) for evaluation of sperm head decondensation and pronuclear formation, and homologous (mouse model) for the study of fertilisation and development. Destruction of mitochondria of the sperm was achieved by exposure to cyanide, a respiratory poison. Rhodamine 123 was used to evaluate the functional integrity of mitochondria. Sperm head decondensation was found to be not statistically significantly affected by mitochondrial damage (p = 0.8), with 62.8% and 67.9% condensation in the experimental and control groups respectively. Male pronucleus formation was seen in 40.2% and 44.4% of the injected oocytes in the experimental and control groups respectively. In the mouse experiments 45.5% and 49.7% of the injected oocytes were fertilised in the mitochondria-damaged and live-intact sperm groups respectively (p = 0.53). Development to blastocyst was achieved in 53.5% and 59.4% of the experimental and control groups respectively; the difference was not significant (p = 0.71). Inner cell mass (ICM) cell number were 15.7 +/- 4.12 and 43.1 +/- 11.3 respectively in the mitochondria-damaged group; the equivalent numbers were 14.12 +/- 4.02 and 39.3 +/- 12.6 in the control group. However, the differences in ICM and total cell counts between these two groups were not significant. Of the blastocysts transferred to pseudopregnant mice, 51.3% (20/36) implanted and 33.4% (12/36) developed to live fetuses in the mitochondria-damaged group. These rates were 60.5% (23/38) and 39.5% (15/38) in the control group. In conclusion, this study shows that functional integrity of the sperm mitochondria is not necessary in the process of fertilisation and development when the sperm is deposited into the ooplasm. Fertilisation and development can be achieved by injection of sperm at the very early stage of necrosis in which only the mitochondria have been destroyed and the rest of the cell including the plasma membrane is still intact.

Animals↗
PubMed1996

Modelling of purine nucleoside metabolism during mouse embryonic development: relative routes of adenosine, deoxyadenosine, and deoxyguanosine metabolism.

The individual activities for adenosine kinase, deoxyadenosine kinase, adenosine deaminase, deoxyguanosine kinase, and purine nucleoside phosphorylase were determined during days 7 to 13 of mouse embryonic development. Adenosine deaminase increased 74-fold between days 7 and 9; deoxyadenosine kinase increased 5.4-fold during the same interval. Adenosine kinase, deoxyguanosine kinase, and purine nucleoside phosphorylase exhibited less than 2-fold changes in activity between days 7 and 13. Using Michaelis constants for each enzyme and the maximal velocities determined from enzyme assay, the relative routes of adenosine and deoxyadenosine metabolism via phosphorylation or deamination were modeled as a function of nucleoside concentration for days 7 through 13. For days 7 and 8, phosphorylation of adenosine is the principle route of metabolism at physiological concentrations. A switch occurred at day 9 and following where deamination is at least 5-fold greater than phosphorylation at all substrate concentrations. Deoxyadenosine phosphorylation was at most 10% of deamination at day 7 and then declined to less than 1% for days 9 to 13. Phosphorolysis was the principle route of deoxyguanosine metabolism through the 7 to 13 day period. Thus catabolism rather than phosphorylation was the principle pathway for purine deoxynucleoside metabolism during this period.

Adenosine↗
PubMed1996

[Apropos of the studies of Lewis, Nusslein-Volhard and Wieschaus, 1995 Nobel prize winners, on the genetic mechanisms of embryonic development of drosophila. A model for human cancer progression].

EB Lewis, C Nusslein-Volhard and E Wieschaus were the winners of the Nobel prize in 1995 for the discovery of genes controling the embryonic development in drosophila. Drosophila development is dependent on sequential activities of three types of genes: the maternal genes, the segmentation genes, and the homeotic genes which are responsible for the segment identity and finally for the building of the body. Mutations of these genes are spectacular because they affect the body structure formed from individual segments. Therefore, the molecular processes regulating the development of inferior organisms such as yeast or more complex as the vertebrates were elucidated by these three researchers. These early biological mechanisms regulate the cell life through interactions with neighbouring cells. We speculate that any alteration of these processes might be implicated in cancer. Understanding of these molecular mechanisms which control cell interactions in cancer constitutes a basis for definition of new prognostic markers and putatively novel therapeutic approaches.

Animals↗
PubMed2004

Effect of chronic hypoxia during embryonic development on physiological functioning and on hatching and post-hatching parameters related to ascites syndrome in broiler chickens.

The present study was designed to investigate the effect of different atmospheric pressure on the endogenous functions of broiler chickens during embryonic, hatching and growing periods related to ascites. Eggs from a commercial broiler line were incubated in two similar commercial incubators at high and low altitudes. The effect on embryonic development and physiological functions including hatching parameters, incidence of ascites and growth performance were examined. Embryos incubated at high altitude had higher plasma tri-iodothyronine, thyroxine, corticosteroid and lactic acid levels, and hatched earlier than those incubated at low altitude. Embryonic mortality was higher at high altitude. Chickens that had been incubated at high altitude showed less right ventricular hypertrophy and ascites mortality than those incubated at low altitude. It was concluded that different atmospheric pressure during incubation interacts with the endocrine functions of the embryo and hence affects hatching parameters, thereby influencing ascites susceptibility.

Altitude↗
PubMed2004

Normal and abnormal embryonic development of the anorectum in rats.

BACKGROUND: The embryologic and pathologic aspect of anorectal malformation (ARM) remains poorly understood. There is no universally accepted theory to explain anorectal embryology and the abnormal development that produces ARM. The aim of this study was to observe the developmental processes of anorectum in rats and to explore the abnormal embryonic development that leads to ARM. METHODS: Rat embryos with ARM were obtained by treating pregnant rats with administration of ethylenethiourea (ETU). Normal rat embryos and embryos with ARM from gestational days 12.5 to 20 were sectioned serially and sagittally and stained with H & E. The relevant structure including cloaca and urorectal septum (URS) were examined in a temporospatial sequence. RESULTS: Characteristics of anorectum development in ARM rat embryos treated by ETU were as follows: (1) URS never fused with cloaca membrane. (2) Dorsal cloacal membrane was maldeveloped. (3) Cloacal configuration was abnormal. (4) Tail groove never appeared. All type of ARM was the rectourethal fistula and common cloaca in ETU-treated rat embryos and was discernible on gestation day 16. CONCLUSIONS: Absence of the tail groove and maldevelopment of the dorsal cloacal membrane, cloacal configuration, and urorectal septum are likely to be responsible for the formation of ARM. Failure of fusion of the URS with cloacal membrane is the immediate reason for rectourethral fistula or common cloaca in ETU-treated rats.

Abnormalities, Drug-Induced↗
PubMed1996

Lack of effect of sex on pig embryonic development in vivo.

The effect of sex on pig conceptus development to day 12 of gestation was investigated. On day 2 of gestation, reciprocal embryo transfers were performed resulting in four groups (Yorkshire-Yorkshire, Yorkshire-Meishan, Meishan-Yorkshire and Meishan-Meishan). Conceptuses at day 12 were recovered from each recipient and diameter, as well as DNA, protein and oestradiol content were determined for individual conceptuses. The sex of individual conceptuses at day 12 was determined by amplification of a fragment of the pig SRY gene, using the polymerase chain reaction. Embryos developed more rapidly to day 12 in Yorkshire recipients, but there was no detectable effect of sex on the diameter, DNA, protein or oestradiol content of conceptuses from any transfer group. Thus, no sex effect was apparent under conditions either promoting or retarding the rate of early pig blastocyst growth. These results provide strong evidence that pig embryonic development occurs at a rate determined by uterine environment and not by sex of the conceptus.

Animals↗