Fetal Chick Research Articles

Reduced genotoxicity of lignin-derivable replacements to bisphenol A studied using in silico, in vitro, and in vivo methods

Bisguaiacols, lignin‐derivable bisphenols, are considered promising and possibly safer alternatives to bisphenol A (BPA), but comprehensive toxicity investigations are needed to ensure safety. Most toxicity studies of BPA and its analogues have focused on potential estrogenic activity, and only limited toxicological data are available on other toxicity aspects, such as genotoxicity at low exposure levels. In this study, the genotoxicity of six lignin-derivable bisguaiacols with varying regioisomer contents and degrees of methoxy substitution was investigated using a multi-tiered method, consisting of in silico simulations, in vitro Ames tests, and in vivo comet tests. The toxicity estimation software tool, an application that predicts toxicity of chemicals using quantitative structure-activity relationships, calculated that the majority of the lignin-derivable bisguaiacols were non-mutagenic. These results were supported by Ames tests using five tester strains (TA98, TA100, TA102, TA1535, and TA1537) at concentrations ranging from 0.5 pmol/plate to 5 nmol/plate. The potential genotoxicity of bisguaiacols was further evaluated using in vivo comet testing in fetal chicken livers, and in addition to the standard alkaline comet assay, the formamidopyrimidine DNA glycosylase enzyme-modified comet assay was employed to investigate oxidative DNA damage in the liver samples. The oxidative stress analyses indicated that the majority of lignin-derivable analogues showed no signs of mutagenicity (mutagenic index < 1.5) or genotoxicity, in comparison to BPA and bisphenol F, likely due to the methoxy groups on the lignin-derivable aromatics. These findings reinforce the potential of lignin-derivable bisphenols as safer alternatives to BPA.

Differential effect of frequency and duration of mechanical loading on fetal chick cartilage and bone development.

Developmental engineering strategies aim to recapitulate aspects of development in vitro as a means of forming functional engineered tissues, including cartilage and bone, for tissue repair and regeneration. Biophysical stimuli arising from fetal movements are critical for guiding skeletogenesis, but there have been few investigations of the biomechanical parameters which optimally promote cartilage and bone development events in in vitro explants. The effect of applied flexion-extension movement frequencies (0.33 and 0.67 Hz) and durations (2 h periods, 1, 2 or 3 × per day) on knee (stifle) joint cartilage shape, chondrogenesis and diaphyseal mineralisation of fetal chick hindlimbs, cultured in a mechanostimulation bioreactor, were assessed both quantitatively and qualitatively. It was hypothesised that increasing frequency and duration of movements would synergistically promote cartilage and bone formation in a dose-dependent manner. Increasing loading duration promoted cartilage growth, shape development and mineralisation of the femoral condyles and tibiotarsus. While increasing frequency had a significant positive effect on mineralisation, hyaline cartilage growth and joint shape were unaffected by frequency change within the ranges assessed, and there were limited statistical interactions between the effects of movement frequency and duration on cartilage or bone formation. Increased glycosaminoglycan deposition and cell proliferation may have contributed to the accelerated cartilage growth and shape change under increasing loading duration. The results demonstrated that frequencies and durations of applied biomechanical stimulation differentially promoted cartilage and bone formation, with implications for developmentally inspired tissue engineering strategies aiming to modulate tissue construct properties.

Effect of fetal calf serum on propagation of duck hepatitis A virus genotype 3 in duck embryo fibroblast cells

BackgroundDuck viral hepatitis (DVH) is a highly contagious viral disease affecting ducks. It can be caused by five agents, including duck hepatitis A virus genotypes 1 (DHAV-1), 2 (DHAV-2), and 3 (DHAV-3), as well as duck hepatitis virus 2 and duck hepatitis virus 3. Since 2007, DHAV-3 has been known to be the most prevalent in East and South Asia. So far, the information regarding the propagation of DHAV-3 in cultured cells is limited. In this study, we describe the comparative studies on the growth properties of DHAV-3 in primary duck embryo fibroblast (DEF) cells using two different strains: a virulent strain C-GY and an attenuated strain YDF120. The effect of fetal calf serum (FCS) and chick serum (CS) on DHAV-3 replication and the mechanism of the inhibitory effect conferred by FCS were also investigated.ResultsFollowing serial passages, both C-GY and YDF120 failed to produce cytopathic effect and plaques. The combined quantitative real-time PCR and indirect immunofluorescence staining methods showed that the two viruses could be propagated productively in DEF cells. Investigation of the viral growth kinetics revealed that the two viruses replicated in DEF cells with similar efficiencies, while the viral load of the virulent C-GY strain peaked more rapidly when compared with the attenuated YDF120 strain. Neutralization assay and time-of-drug-addition study indicated that FCS displayed inhibitory effect on DHAV-3 replication. Analysis on the mechanism of action of FCS against DHAV-3 demonstrated that the inhibitory effect was reflected at three steps of the DHAV-3 life cycle including adsorption, replication, and release.ConclusionsBoth virulent and attenuated DAHV-3 strains can establish noncytocidal, productive infections in DEF cells. The virulent strain replicates more rapidly than the attenuated strain in early infection period. FCS has an inhibitory effect on DHAV-3 replication, which may be attributed to action of a non-specific inhibitory factor present in FCS directly on the virus. These findings may provide new insights into the development of potential antiviral agents.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P10. Infant positioning impacts neck and back muscle activity: a pilot study exploring implications for spinal development

BACKGROUND CONTEXT Since 1992, pediatricians have recommended that all infants be placed to sleep in the supine or side-lying position to reduce the risk of Sudden Infant Death Syndrome (SIDS). Although this policy successfully reduced the incidence of SIDS by nearly 50%, questions regarding the positional impact on musculoskeletal and motor development have since surfaced. Studies have linked prone positioning to extensor muscle development and motor milestone achievements, and some believe a link can be made between infant positioning and idiopathic infantile scoliosis. Recently, a relationship between muscle forces and spinal curvatures, particularly hyperkyphosis, was found in fetal chicks, leading to more questions regarding the role of the paraspinal muscles in early spinal development/deformity. PURPOSE The purpose of this pilot study is to examine relationships between infant positions and neck or back muscle activity using electromyography (EMG). STUDY DESIGN/SETTING Electromyographic research study. PATIENT SAMPLE Healthy infants aged 2-7 months. OUTCOME MEASURES Normalized mean EMG data. METHODS Seven healthy infants (mean 5.2 months, 5 male) were enrolled in the study. Surface EMG recorded muscle activity of bilateral cervical paraspinal and erector spinae muscles during five 30-second tasks: laying prone, laying supine, held in arms, held in a baby carrier, and in a car seat. EMG data was normalized to the prone task, and paired t-tests were used to compare to the prone position (p RESULTS Infants exhibited significantly more erector spinae activity during prone positioning compared to all other tasks, and twice as much compared to the supine position (p CONCLUSIONS This first look at the muscle activity of healthy infants in common positions supports the importance of prone time in neck and back development. Prone time significantly increases erector spinae activity. As subject enrollment continues, the in-carrier position may show comparable neck muscle activity to the prone position, as the baby must support the weight of the head while upright.

Magnetic ion channel activation of TREK1 in human mesenchymal stem cells using nanoparticles promotes osteogenesis in surrounding cells

Magnetic ion channel activation technology uses superparamagnetic nanoparticles conjugated with targeting antibodies to apply mechanical force directly to stretch-activated ion channels on the cell surface, stimulating mechanotransduction and downstream processes. This technique has been reported to promote differentiation towards musculoskeletal cell types and enhance mineralisation. Previous studies have shown how mesenchymal stem cells injected into a pre-mineralised environment such as a foetal chick epiphysis, results in large-scale osteogenesis at the target site. However, the relative contributions of stem cells and surrounding host tissue has not been resolved, that is, are the mesenchymal stem cells solely responsible for the observed mineralisation or do mechanically stimulated mesenchymal stem cells also promote a host-tissue mineralisation response? To address this, we established a novel two-dimensional co-culture assay, which indicated that magnetic ion channel activation stimulation of human mesenchymal stem cells does not significantly promote migration but does enhance collagen deposition and mineralisation in the surrounding cells. We conclude that one of the important functions of injected human mesenchymal stem cells is to release biological factors (e.g., cytokines and microvesicles) which guide the surrounding tissue response, and that remote control of this signalling process using magnetic ion channel activation technology may be a useful way to both drive and regulate tissue regeneration and healing.

Induction of male germ cell-like lineage from chicken fetal bone marrow stem cells with chicken testis extract

Bone marrow-derived stem cells (BMCs) are able to differentiate into multilineage cells such as muscle, bone, cartilage, fat, and nerve cells. In the present study, we investigated the differentiation capability of chicken BMCs into germ cells by using retinoic acid (RA) and chicken testis extract (chTE). The chicken BMCs were isolated from fetal chicken femurs on post-fertilization day 20, cultured in vitro, and treated with RA and chTE, respectively. The cultured chicken BMCs displayed fibroblast-like morphology and were positive for mesenchymal-specific markers such as CD44, CD90, and CD105 at the mRNA level. RT-PCR and immunocytostaining revealed that both RA and chTE treatments induced the expression of early-germ-cell markers such as Stra8, Dazl and DDX4. The increase of germ cell-specific gene expression after chTE treatment indicates that testicular environment-derived proteins may induce in vitro germ-cells. In addition, we performed a microarray analysis to identify differentially expressed genes (DEGs) in RA and chTE, respectively. A total of 1,629 DEGs were obtained and the chTE treatment showed very lower numbers of DEGs than the RA treatment. Collectively, our results indicate that chicken BMCs have the potential to differentiate to male germ cells in vitro with testis derived proteins.

The Significance of Key Amino Acid Sequences in the Digestibility and Toxicity of Gliadin Peptides in Celiac Disease

The importance of alternative or adjunct treatments to the gluten-free diet in celiac disease is now being recognized. This paper discusses the scientific principles behind the use of caricain for enzyme therapy. Objective: To review the structures of the toxic peptides in A-gliadin that relate to those found by other workers insofar as having key sequences of amino acids or motifs which relate to toxicity, especially in regard to difficulty of digestion or immunogenicity. Methods: Structures of synthetic A-gliadin peptides shown to be toxic in the fetal chick assay were examined before and after digestion with duodenal mucosa from patients in long remission. Synthetic peptides corresponding to the undigested residues were also assayed and the key amino acid sequences compared in order to determine if they could be related to direct toxicity and immunogenicity of the peptides. Results: The results showed that the smallest toxic peptides from celiac mucosal digestion were octa-peptides and that they were obtained in greater yield than similar products from normal digestion. One of those peptides corresponded to residues 12-19 of A-gliadin and contained the key motifs PSQQ and QQQP of De Ritis et al. , whilst the other corresponded to residues 72-79 and contained the key motif PYPQ (extending to PYPQPQ), observed by other workers, especially those who have been investigating immunological activity over the past two decades. Conclusions: The presence of key motifs in undigested residues from celiac mucosal digestion and the greater prevalence of these residues compared with residues from normal digestion justifies our work on enzyme therapy. These studies have also indicated that our use of caricain as an enzyme capable of digesting peptides with two different types of toxicity has a sound scientific basis.

63 THE EFFECT OF A MODIFIED CRYOPRESERVATION METHOD ON THE VIABILITY OF FROZEN–THAWED PRIMORDIAL GERM CELL ON THE KOREAN NATIVE CHICKEN (Ogye)

Cryopreservation of poultry semen has been reported, but preservation of female genetic material has not been possible because of the unique anatomical and physiological characteristics of the avian egg. Thus, conservation of genetic material in chickens was attempted by preserving primordial germ cells (PGC) in LN2. This study established a method for preserving chicken PGC that enables long-term storage in LN2 for preservation of species. The purpose of this study was to clarify the effects of fetal bovine serum (FBS) or chicken serum (CS) treatment on the viability of cryopreserved PGC in the Korean native chicken (Ogye). Primordial germ cells were separated from a germinal gonad using a fine glass micropipette under a microscope and were suspended in a freezing medium containing freezing and protecting agents [e.g. dimethyl sulfoxide (DMSO) and ethylene glycol (EG)]. The PGC were then purified using the magnetic-activated cell sorting (MACS) method. The viability of the PGC in both groups was determined by the trypan blue exclusion method. The values of the 0, 5, 10, and 15% DMSO plus FBS treatment were 21.6, 30.36, 36.42, 50.39, and 48.36%, respectively. The viability of PGC after freeze-thawing was significantly higher for the 10% EG plus FBS treatment than for the 10% EG plus CS treatment (P &lt; 0.05; 64.36 v. 50.66%). This study established a method for preserving chicken PGC that enables systematic storage and labelling of cryopreserved PGC in LN2 at a germplasm repository and ease of entry into a database. In the future, the importance of this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germ line chimeras.

Differential Effects of Hypoxic and Hyperoxic Stress-Induced Hypertrophy in Cultured Chick Fetal Cardiac Myocytes

The adult heart responds to contraction demands by hypertrophy, or enlargement, of cardiac myocytes. Adaptive hypertrophy can occur in response to hyperoxic conditions such as exercise, while pathological factors that result in hypoxia ultimately result in heart failure. The difference in the outcomes produced by pathologically versus physiologically induced hypertrophy suggests that the cellular signaling pathways or conditions of myocytes may be different at the cellular level. The structural and functional changes in myocytes resulting from hyperoxia (simulated using hydrogen peroxide) and hypoxia (using oxygen deprivation) were tested on fetal chick cardiac myocytes grown in vitro. Structural changes were measured using immunostaining for α-sarcomeric actin or MyoD, while functional changes were assessed using immunostaining for calcium/calmodulin-dependent kinase (CaMKII) and by measuring intracellular calcium fluxes using live cell fluorescence imaging. Both hypoxic and hyperoxic stress resulted in an upregulation of actin and MyoD expression. Similarly, voltage-gated channels governing myocyte depolarization and the regulation of CaMK were unchanged by hyperoxic or hypoxic conditions. However, the dynamic features of calcium fluxes elicited by caffeine or epinephrine were different in cells subjected to hypoxia versus hyperoxia, suggesting that these different conditions differentially affect components of ligand-activated signaling pathways that regulate calcium. Our results suggest that changes in signaling pathways, rather than structural organization, may mediate the different outcomes associated with hyperoxia-induced versus hypoxia-induced hypertrophy, and these changes are likely initiated at the cellular level.

Cyclic hydrostatic pressure stimulates enhanced bone development in the foetal chick femur in vitro

Mechanical loading of bone and cartilage in vivo results in the generation of cyclic hydrostatic forces as bone compression is transduced to fluid pressure in the canalicular network and the joint synovium. It has therefore been suggested that hydrostatic pressure is an important stimulus by which osteochondral cells and their progenitors sense and respond to mechanical loading in vivo. In this study, hydrostatic pressure regimes of 0–279kPa at 0.005–2Hz were applied to organotypically cultured ex vivo chick foetal femurs (e11) for 1hour per day in a custom designed bioreactor for 14days and bone formation assessed by X-ray microtomography and qualified by histology. We found that the mineralised portion of the developing femur cultured under any cyclic hydrostatic pressure regime was significantly larger and/or denser than unstimulated controls but that constant (non-cycling) hydrostatic pressure had no effect on bone growth. Further experiments showed that the increase in bone formation was directly proportional to stimulation frequency (R2=0.917), but independent of the magnitude of the pressure applied, whilst even very low frequencies of stimulation (0.005Hz) had significant effects on bone growth. Expression of Type-II collagen in both epiphyses and diaphysis was significantly upregulated (1.48-fold and 1.95-fold respectively), together with osteogenic genes (osteonectin and osteopontin) and the osteocyte maturation marker CD44. This work demonstrates that cyclic hydrostatic pressure promotes bone growth and mineralisation in a developmental model and supports the hypothesis that hydrostatic forces play an important role in regulating bone growth and remodelling in vivo.

Angioneural Crosstalk in Scaffolds with Oriented Microchannels for Regenerative Spinal Cord Injury Repair

The aim of our work is to utilize the crosstalk between the vascular and the neuronal system to enhance directed neuritogenesis in uniaxial guidance scaffolds for the repair of spinal cord injury. In this study, we describe a method for angioneural regenerative engineering, i.e., for generating biodegradable scaffolds, produced by a combination of controlled freezing (freeze-casting) and lyophilization, which contain longitudinally oriented channels, and provide uniaxial directionality to support and guide neuritogenesis from neuronal cells in the presence of endothelial cells. The optimized scaffolds, composed of 2.5 % gelatin and 1 % genipin crosslinked, were characterized by an elastic modulus of ~51 kPa and longitudinal channels of ~50 μm diameter. The scaffolds support the growth of endothelial cells, undifferentiated or NGF-differentiated PC12 cells, and primary cultures of fetal chick forebrain neurons. The angioneural crosstalk, as generated by first forming endothelial cell monolayers in the scaffolds followed by injection of neuronal cells, leads to the outgrowth of long aligned neurites in the PC12/endothelial cell co-cultures also in the absence of exogenously added nerve growth factor. Neuritogenesis was not observed in the scaffolds in the absence of the endothelial cells. This methodology is a promising approach for neural tissue engineering and may be applicable for regenerative spinal cord injury repair.

217 PROTEIN-INDUCED TRANSDIFFERENTIATION INTO MALE GERM CELL-LIKE LINEAGE FROM CHICKEN FETAL BONE MARROW STEM CELLS

Bone marrow (BM)-derived stem cells are capable of transdifferentiation into multilineage cells like muscle, bone, cartilage, fat and nerve cells. In this study, we investigated the capability of mesenchymal stem cells (MSC) derived from BM into germ cell differentiation in the chicken. Chicken MSCs were isolated from BM of day 20 fertilized fetal chicken with Ficoll-Paque Plus. Isolated cells were cultured in advance-DMEM (ADMEM) supplemented with 10% fetal bovine serum and antibiotics. Once confluent, cells were subcultured until five passages. The cultured cells showed fibroblast-like morphology. The cells had positive expressions of Oct4, Sox2 and Nanog. Two induction methods were conducted to examine the ability of transdifferentation into male germ cells. In group 1, MSC were cultured in ADMEM containing retinoic acid and chicken testicular extracts proteins for 10 to 15 days. In group 2, MSC were permeabilized by streptolysin O and treated with chicken testicular protein extracts. In both treatment groups, MSC were cultured in ADMEM containing retinoic acid for 10 to 15 days. We found that chicken MSC had a positive expression of pluripotent proteins such as Oct4, Sox2, Nanog and a small population of chicken MSC seem to transdifferentiate into male germ cell-like cells. These cells expressed early germ cell markers and male germ-cell-specific markers (Dazl, C-kit, Stra8 and DDX4) as analysed by reverse transcription-PCR and immunohistochemistry. These results demonstrated that chicken MSC may differentiate into male germ cells and the same might be used as a potential source of cells for production of transgenic chickens. This study was carried out with the support of Agenda Program (Project No. PJ0064692011), RDA and Republic of Korea.

Use of 2–4 H magnetic resonance spectroscopy (MRS) biomarkers to predict 48 H MRS and histology outcome biomarkers in a piglet model of perinatal asphyxia

Research into treatment of stroke and neonatal hypoxic-ischaemic (HI) insult has been beset by high variability in clinical and histopathology outcome despite similar insult severity, necessitating large groups to produce...

Prdm1 (Blimp-1) and the Expression of Fast and Slow Myosin Heavy Chain Isoforms during Avian Myogenesis In Vitro

BackgroundMultiple types of fast and slow skeletal muscle fibers form during early embryogenesis in vertebrates. In zebrafish, formation of the earliest slow myofibers in fin muscles requires expression of the zinc-finger transcriptional repressor Prdm1 (also known as Blimp1). To further understand how the role of Prdm1 in early myogenesis may vary through evolution and during development, we have now analyzed Prdm1 expression in the diverse types of myotubes that form in culture from somitic, embryonic, and fetal chicken myoblasts.Principal FindingsIn cultures of somitic, embryonic limb, and fetal limb chicken cells, we found that Prdm1 was expressed in all of the differentiated muscle cells that formed, including those that expressed only fast myosin heavy chain isoforms, as well as those that co-expressed both fast and slow myosin heavy chain isoforms. Prdm1 was also expressed in Pax7-positive myoblasts, as well as in non-myogenic cells in the cultures. Furthermore, though all differentiated cells in control somite cultures co-expressed fast and slow myosin heavy chains, antisense knockdown of Prdm1 expression inhibited the formation of these co-expressing cells in somite cultures.ConclusionsIn chicken myogenic cell cultures, Prdm1 was expressed in most Pax7-positive myoblasts and in all differentiated muscle cells, irrespective of the developmental stage of cell donor or the pattern of fast and slow myosin heavy chains expressed in the differentiated cells that were formed. Thus, Prdm1 was expressed in myogenic cells prior to terminal differentiation; and, after differentiation, Prdm1 expression was not limited to cells that expressed slow myosin heavy chain isoforms. In addition, Prdm1 appeared to be required for differentiation of the somitic myocytes, which are the earliest myocytes to form in the avian embryo.

Hypoxia sensing in the fetal chicken femoral artery is mediated by the mitochondrial electron transport chain

Vascular hypoxia sensing is transduced into vasoconstriction in the pulmonary circulation, whereas systemic arteries dilate. Mitochondrial electron transport chain (mETC), reactive O(2) species (ROS), and K(+) channels have been implicated in the sensing/signaling mechanisms of hypoxic relaxation in mammalian systemic arteries. We aimed to investigate their putative roles in hypoxia-induced relaxation in fetal chicken (19 days of incubation) femoral arteries mounted in a wire myograph. Acute hypoxia (Po(2) approximately 2.5 kPa) relaxed the contraction induced by norepinephrine (1 microM). Hypoxia-induced relaxation was abolished or significantly reduced by the mETC inhibitors rotenone (complex I), myxothiazol and antimycin A (complex III), and NaN(3) (complex IV). The complex II inhibitor 3-nitroproprionic acid enhanced the hypoxic relaxation. In contrast, the relaxations mediated by acetylcholine, sodium nitroprusside, or forskolin were not affected by the mETC blockers. Hypoxia induced a slight increase in ROS production (as measured by 2,7-dichlorofluorescein-fluorescence), but hypoxia-induced relaxation was not affected by scavenging of superoxide (polyethylene glycol-superoxide dismutase) or H(2)O(2) (polyethylene glycol-catalase) or by NADPH-oxidase inhibition (apocynin). Also, the K(+) channel inhibitors tetraethylammonium (nonselective), diphenyl phosphine oxide-1 (voltage-gated K(+) channel 1.5), glibenclamide (ATP-sensitive K(+) channel), iberiotoxin (large-conductance Ca(2+)-activated K(+) channel), and BaCl(2) (inward-rectifying K(+) channel), as well as ouabain (Na(+)-K(+)-ATPase inhibitor) did not affect hypoxia-induced relaxation. The relaxation was enhanced in the presence of the voltage-gated K(+) channel blocker 4-aminopyridine. In conclusion, our experiments suggest that the mETC plays a critical role in O(2) sensing in fetal chicken femoral arteries. In contrast, hypoxia-induced relaxation appears not to be mediated by ROS or K(+) channels.

Pulmonary Vascular Endothelial Growth Factor Expression and Disaturated Phospholipid Content in a Chicken Model of Hypoxia-Induced Fetal Growth Restriction

Background: Prenatal hypoxia is an important cause of intrauterine growth retardation that affects fetal lung maturation, although previous studies have rendered conflicting results. The fetal chicken model allows the study of the isolated effects of hypoxia during development. Objectives: We hypothesized that prenatal hypoxia would differentially affect surfactant synthesis, depending on timing and duration of hypoxia. Pulmonary vascular endothelial growth factor (VEGF) expression was analyzed as a possible link between oxygen sensing and surfactant production. Methods: Fertilized White Leghorn eggs were incubated in normoxia, hyperoxia (60% O₂) from day 15 or hypoxia (15% O₂) from either day 6 or day 15 of incubation. Whole lung disaturated phospholipids (DSPL) and mRNA expression of VEGF isoforms were quantified at day 16 and 19. Results: Lung DSPL content increased approximately threefold between day 16 and 19 in control animals. Both hypoxia and hyperoxia from day 15 significantly increased DSPL content at day 19 versus control (103 ± 22 and 116 ± 18 vs. 81 ± 15 µg/mg protein, p < 0.01 and p < 0.001, respectively), while long-term hypoxia tended to decrease DSPL content (65 ± 17 µg/mg protein, p = 0.056). No differences in DSPL content were observed at day 16. Short-term hypoxia transiently up-regulated VEGF146 1.5-fold at day 16 (p < 0.05). A similar trend was observed for VEGF122 (p = 0.058) and VEGF190 (p = 0.08), while no differences were present at day 19. Conclusions: Both prenatal hypoxia and hyperoxia induced during critical windows of lung development differentially modulate surfactant synthesis. Our data support the concept that fetal oxygen tension is a key signal in the regulation of the surfactant system.

Ultrasound exposure of the foetal chick brain: effects on learning and memory

Ultrasound imaging of the brain is routinely used to monitor the development and resolution of brain lesions among premature and compromised newborn human babies. However, animal studies have shown that ultrasound can cause damage to developing foetal and neonatal tissues. In this study we investigated if ultrasound of the chick brain can lead to learning and memory impairment after hatch. We exposed the brains of chicks on day 19 of a 21 day incubation period to 5 or 10min of B-mode, or to 1, 2, 3, 4 or 5min of pulsed Doppler ultrasound in ovo. Learning and memory function were assessed at day 2 post-hatch. Our results show that B-mode exposure at E19 does not affect memory function. On the other hand, 2h after training, significant memory impairment occurred following 4 and 5min of pulsed Doppler exposure at E19. In separate groups of chicks, short-, intermediate- and long-term memory was equally impaired suggesting an inability to learn. Further, the chicks were still unable to learn with a second training session 5min after completion of the initial testing. These results demonstrate that extended exposure to pulsed Doppler ultrasound can adversely affect cognitive function in the chick when exposure occurs close to the time of hatch.

Herzgewebe aus embryonalen Stammzellen

Embryonic stem cells can give rise to all somatic cells, making them an attractive cell source for tissue engineering applications. The propensity of cells to form tissue-like structures in a culture dish has been well documented. We and others made use of this intrinsic property to generate bioartificial heart muscle. First proof-of-concept studies involved immature heart cells mainly from fetal chicken, neonatal rats and mice. They eventually provided evidence that force-generating heart muscle can be engineered in vitro. Recently, the focus shifted to the application of stem cells to eventually enable the generation of human heart muscle and reach following long-term goals: (1) development of a simplified in vitro model of heart muscle development; (2) generation of a human test-bed for drug screening and development; (3) allocation of surrogate heart tissue to myocardial repair applications. This overview will provide the background for cell-based myocardial repair, introduce the main myocardial tissue engineering concepts, discuss the use of embryonic and non-embryonic stem cells, and lays out the potential direct and indirect therapeutic use of human tissue engineered myocardium.

Harvey's and Highmore's Accounts of Chick Generation

AbstractHarvey and Highmore experimented together on chick fetuses at Oxford in the early 1640s, yet in 1651 published significantly different treatises on generation that emphasize their reliance on observations and dissections of fetal chicks at different stages of incubation. The key differences follow from their views on matter and souls. Harvey conceives of living bodies as governed by Aristotelian souls and faculties. Highmore views matter as made of corpuscles and describes organs as involved in chemical procedures. Highmore's treatise is a response to Digby's claim that heat, moisture, and pressure could explain generation. Although Digby's treatment lacks Harvey's and Highmore's attention to detail, it offers a point of comparison that leads to a more nuanced understanding of their explanation. Moreover, Highmore's dedication of his work to Boyle provides a new perspective on both men's intellectual evolution from the latter part of the 1640s to 1651.

Fetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart

HomeCirculation ResearchVol. 101, No. 10Fetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBFetal Atrial Septoplasty Is Performed for Left Atrial Decompression but not for Enhancing Preload to a Hypoplastic Left Heart Thomas Kohl Thomas KohlThomas Kohl German Center for Fetal Surgery & Minimally-Invasive Therapy, University of Bonn, Germany Search for more papers by this author Originally published9 Nov 2007https://doi.org/10.1161/CIRCRESAHA.107.164202Circulation Research. 2007;101:e113To the Editor:I thank Drs de Almeida, McQuinn, and Sedmera for demonstrating that an increase in ventricular preload is compensated by myocyte proliferation in normal and hypoplastic fetal chick left ventricle.1 The results of their study clearly provide further impetus to develop fetal cardiac interventions for hypoplastic left heart syndromes with intrinsically normal or only mildly stenotic mitral and aortic valves.The purpose of my letter is to point out an incorrect concept that the authors put forth in their discussion. Regarding the rationale behind percutaneous ultrasound-guided fetal atrial septoplasty, the authors state from clinical data collected by Marshall et al2 that “despite technical successful septoplasty the transseptal flow to the left atrium was minimal, pointing out the need of an additional procedure to force the blood into the left heart structures.” The opposite is the case: Atrial septoplasty in fetuses with hypoplastic left heart syndrome with intact or highly restrictive atrial septum is performed on one hand to enable pulmonary venous blood to reach the systemic circulation postnatally and on the other hand to alleviate severe pulmonary congestion by left atrial decompression toward the right side of the heart prenatally. The better outcomes in prenatally treated fetuses with this condition support the rationale that alleviation of pulmonary congestion improves abnormal muscularization of pulmonary veins and, by this mechanism, contributes to a lower risk of intractable pulmonary hypertension in these critically ill infants after birth.1 deAlmeida A, McQuinn T, Sedmera D. Increased ventricular preload is compensated by myocyte proliferation in normal and hypoplastic fetal chick left ventricle. Circ Res. 2007; 100: 1363–1370.LinkGoogle Scholar2 Marshall AC, van der Velde ME, Tworetzky W, Gomez CA, Wilkins-Haug L, Benson CB, Jennings RW, Lock JE. Creation of an atrial septal defect in utero for fetuses with hypoplastic left heart syndrome and intact or highly restrictive atrial septum. Circulation. 2004; 110: 253–258.LinkGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails November 9, 2007Vol 101, Issue 10 Advertisement Article InformationMetrics https://doi.org/10.1161/CIRCRESAHA.107.164202PMID: 17991886 Originally publishedNovember 9, 2007 Keywordspulmonary hypertensionpulmonary congestionfetal atrial septoplastyPDF download Advertisement