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Child's Nervous System : ChNS :... Jan 2023Proximal ventricular shunt catheter occlusion remains a problematic cause of shunt malfunction, and there is no consistent in vivo or in vitro model to help clinicians...
PURPOSE
Proximal ventricular shunt catheter occlusion remains a problematic cause of shunt malfunction, and there is no consistent in vivo or in vitro model to help clinicians and researchers study this phenomenon.
METHODS
An in vitro model utilizing standard proximal ventricular catheter and biological occluding agents mimicking choroid plexus was designed, constructed, and calibrated to occlude consistently within a specified timeframe. Hydrostatic pressure differential of 100 cmHO was used as a driving force to generate flow through the catheter. Chalaza and vitelline membranes were harvested from avian eggs and used as occluding agents. Successful occlusion was defined as a greater than 90% reduction in volumetric flow rate through distal outlet. Histological sections of occluded catheters were performed and interpreted by a neuropathologist.
RESULTS
Initial trials demonstrated successful standard catheter occlusion within 24 h using chalaza, vitelline membrane, and combination treatments. Repeat trials demonstrated consistency in successful occlusion within 5 min utilizing only vitelline membrane treatment. Histopathology demonstrated the vitelline membrane to consist of a thin, superficial layer of extraembryonic ectoderm; the chalaza was observed to consist of strands of mucin protein.
CONCLUSIONS
An in vitro model of proximal ventricular shunt catheter occlusion was developed and calibrated for successful occlusion within 5 min. Future studies may utilize this model to rapidly test occlusion-resistant shunt designs and de-obstruction techniques.
Topics: Humans; Cerebrospinal Fluid Shunts; Hydrocephalus; Equipment Design; Choroid Plexus; Catheters; Ventriculoperitoneal Shunt
PubMed: 36169702
DOI: 10.1007/s00381-022-05689-z -
Open Biology Sep 2022During early avian development, only a narrow band of cells (the edge cells, also called 'margin of overgrowth') at the rim of the embryo is responsible for blastoderm...
During early avian development, only a narrow band of cells (the edge cells, also called 'margin of overgrowth') at the rim of the embryo is responsible for blastoderm expansion by crawling over the vitelline membrane (VM) to cover the whole egg yolk in just 4 days (a process called epiboly). Surprisingly, this has not yet been studied in detail. Here we explore the edge cells of the chick embryo using hybridization, immunohistochemistry and live imaging. Morphological and molecular properties reveal that the edge has a distinctive structure, being subdivided into sub-regions, including at least four distinct zones (which we name as leading, trailing, deep and stalk zones). This allows us to study reorganization of the edge region that accompanies reattachment of an explanted blastoderm to the VM. Immunohistochemistry uncovers distinct polarized cellular features resembling the process of collective cell migration described in other systems. Live imaging reveals dynamic lamellipodial and filopodial activity at the leading edge of the outermost cells. Our data provide evidence that edge cells are a distinct tissue. We propose that edge cells may be a useful model system for the study of wound healing and other closure events in epithelial cell sheets.
Topics: Animals; Blastoderm; Cell Movement; Chick Embryo; Epithelial Cells; Vitelline Membrane; Wound Healing
PubMed: 36128719
DOI: 10.1098/rsob.220147 -
International Journal of Molecular... Aug 2022Vitelline membrane proteins (VMPs) are the main proteins that form the inner shell (vitelline membrane layer) of insect eggs and are an integral part of egg formation...
Vitelline membrane proteins (VMPs) are the main proteins that form the inner shell (vitelline membrane layer) of insect eggs and are an integral part of egg formation and embryo development. Here, we characterized the molecular structure and expression patterns of the gene and analyzed its reproductive functions in diamondback moth, (L.), a worldwide migratory pest of cruciferous plants. The gene was shown to be a single exon gene that contained an open reading frame of 852 base pairs (bp) encoding 283 amino acids. Both qPCR and western blot analyses showed that VMP26 was specifically expressed in female adults and was significantly highly expressed in the ovary. Further anatomical analysis indicated that the expression level of in the ovarian tube with an incomplete yolk was significantly higher than that in the ovarian tube with a complete yolk. CRISPR/Cas9-induced knockout successfully created two homozygous strains with 8- and 46-bp frameshift mutations. The expression deficiency of the VMP26 protein was detected in the mutant strains using immunofluorescence and western blot. No significant difference was found in the number of eggs laid within three days between wild and mutant individuals, but there was a lower egg hatchability. The loss of the gene changed the mean egg size, damaged the structure of the vitelline membrane, and increased the proportion of abnormal eggs due to water loss, resulting in egg collapse. This first analysis of the roles of the gene in the oocyte formation and embryonic development of , using CRISPR/Cas9 technology, provides a basis for screening new genetic control targets of .
Topics: Animals; CRISPR-Cas Systems; Egg Proteins; Female; Moths; Mutagenesis; Vitelline Membrane
PubMed: 36076934
DOI: 10.3390/ijms23179538 -
Membranes Jul 2022oocytes are commonly used in many fundamental biological studies. One of the major limitations of oocytes is their short storage lifespan with most defolliculated...
oocytes are commonly used in many fundamental biological studies. One of the major limitations of oocytes is their short storage lifespan with most defolliculated oocytes physically deteriorating in 10 days or less. Herein, we identified a 3D Cultrex-based storage media that incorporates extracellular membrane-based hydrogels to maintain oocyte integrity. Under these treatments, the lifespan of the oocytes increased to more than 20 days compared to standard conditions. The treatment preserved the oocytes membrane integrity and did not interfere with mRNA- or cDNA-derived protein expression.
PubMed: 36005669
DOI: 10.3390/membranes12080754 -
Applied Microscopy Jul 2022We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also...
We examined the morphology of the fertilized egg and the fine structure of fertilized egg envelopes of Poropanchax normani belonging to the family Poeciliidae, also known as Norman's lampeye using light and electron microscopes. The fertilized eggs with narrow perivitelline space were found to be spherical and demersal, additionally containing small oil droplets in the vitelline membrane. Further, a bundle of adhesive filaments was observed to be present on one side of the fertilized egg. These filaments possessed remarkably high elasticity and were approximately 1-3 mm in length. The size of the fertilized egg was determined to be about 1.49 ± 0.07 mm (n = 30). The outer surface appeared smooth, and adhesive filaments originating at different location of the surface of the envelope were found to be distributed around the egg envelope and were joined together to form a single long bundle in scanning electron microscopic observation. A peak-like structure formed of several straight wrinkles was observed around the micropyle. However, the complete structure of the micropyle could not be studied due to the depth at which it was located. Additionally, the total thickness of the egg envelope was ascertained to be approximately12.5-14.5 μm. The egg envelope consisted of two distinct layers, an outer electron dense layer and an inner lamellar layer, further consisting of 10 sublayers of varying thicknesses. Collectively, it was observed that the morphological characteristics of the fertilized egg, fine structures surrounding the micropyle, outer surface, adhesive structure consisting adhesive filaments, and sections of fertilized egg envelope displayed species specificity.
PubMed: 35831688
DOI: 10.1186/s42649-022-00075-0 -
Zygote (Cambridge, England) Oct 2022Ascidians (Urochordate) are hermaphroditic marine invertebrates that release sperm and eggs to the surrounding seawater. However, several ascidians, including and show...
Ascidians (Urochordate) are hermaphroditic marine invertebrates that release sperm and eggs to the surrounding seawater. However, several ascidians, including and show strict self-sterility due to a self/nonself-recognition mechanism in the interaction between sperm and the vitelline coat (VC) of the eggs. We have previously reported that sperm intracellular Ca level drastically increased immediately after sperm binding to the VC of self eggs but not nonself eggs in type A, which was potently inhibited by lowering the external Ca concentration, suggesting that sperm Ca influx occurs after sperm self-recognition on the VC. Here, we investigated whether self-sterility was abolished by lowering the external Ca concentration in The results showed that the block to self-fertilization was removed by low-Ca (∼1 mM) seawater without decreasing the fertilization rate. Such an effect was not observed with Mg or K. These results led us to conclude that a low-Ca environment is sufficient to block the self-recognition signal upon fertilization. As low-Ca seawater showed no effect on self-sterility, we propose that the mechanism of self-sterility in must be distinctive from that in .
Topics: Animals; Calcium; Ciona intestinalis; Fertilization; Infertility; Male; Seawater; Self-Fertilization; Semen; Spermatozoa; Urochordata; Vitelline Membrane
PubMed: 35686329
DOI: 10.1017/S0967199422000144 -
Cells Apr 2022In sea urchin, the immediate contact of the acrosome-reacted sperm with the egg surface triggers a series of structural and ionic changes in the egg cortex. Within one...
In sea urchin, the immediate contact of the acrosome-reacted sperm with the egg surface triggers a series of structural and ionic changes in the egg cortex. Within one minute after sperm fuses with the egg plasma membrane, the cell membrane potential changes with the concurrent increases in intracellular Ca levels. The consequent exocytosis of the cortical granules induces separation of the vitelline layer from the egg plasma membrane. While these cortical changes are presumed to prevent the fusion of additional sperm, the subsequent late phase (between 1 and 4 min after fertilization) is characterized by reorganization of the egg cortex and microvilli (elongation) and by the metabolic shift to activate de novo protein and DNA syntheses. The latter biosynthetic events are crucial for embryonic development. Previous studies suggested that the early phase of fertilization was not a prerequisite for these changes in the second phase since the increase in the intracellular pH induced by the exposure of unfertilized sea urchin eggs to ammonia seawater could start metabolic egg activation in the absence of the cortical granule exocytosis. In the present study, we have demonstrated that the incubation of unfertilized eggs in ammonia seawater induced considerable elongations of microvilli (containing actin filaments) as a consequence of the intracellular pH increase, which increased the egg's receptivity to sperm and made the eggs polyspermic at fertilization despite the elevation of the fertilization envelope (FE). These eggs also displayed compromised Ca signals at fertilization, as the amplitude of the cortical flash was significantly reduced and the elevated intracellular Ca level declined much faster. These results have also highlighted the importance of the increased internal pH in regulating Ca signaling and the microvillar actin cytoskeleton during the late phase of the fertilization process.
Topics: Actin Cytoskeleton; Ammonia; Animals; Hydrogen-Ion Concentration; Male; Sea Urchins; Zygote
PubMed: 35563801
DOI: 10.3390/cells11091496 -
Journal of Food Science May 2022Herein, the water and lipid migration of salted duck eggs during storage were systematically explored in three different packaging conditions of long-term salting, no...
Herein, the water and lipid migration of salted duck eggs during storage were systematically explored in three different packaging conditions of long-term salting, no packaging, and vacuum packaging. Bound water, multilayer bound water, lipid, and bulk water were observed in the whole duck egg by low-field nuclear magnetic resonance (LF-NMR) relaxation. Five weeks of salting process led to the redistribution of water and lipid due to the watery state of egg white and the gelation of egg yolk due to the permeation of salt, and boiling mainly caused an obvious decrease in the mobility of bulk water due to the gelation of egg white. Among these three conditions, long-term salting with 6 months storage caused the most serious redistribution of water and lipid as well as the rupture of the vitelline membrane, but could prevent the oxidation of egg yolk. Vacuum packaging had the least influence on the water and lipid distribution, mass change, and water content but led to lipid oxidation with high degree in egg yolk. However, the most obvious mass loss was observed in the salted duck eggs during the storage without packaging. In addition, principal component analysis of Carr-Purcell-Meiboom-Gill data suggested that LF-NMR could distinguish the salted duck eggs with different storage times during the early stage of the storage. Practical Application Water and lipid migration of salted duck eggs during storage with three packaging conditions were explored by using low-field nuclear magnetic resonance and magnetic resonance imaging. Understanding the impacts of packaging conditions on water and lipid migration of salted duck eggs during storage could provide a new method for the quality identification.
Topics: Animals; Ducks; Egg Yolk; Eggs; Lipids; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Sodium Chloride; Water
PubMed: 35411557
DOI: 10.1111/1750-3841.16139 -
Journal of the Science of Food and... Oct 2022Egg yolk is recognized for its excellent nutritional benefit and economic value; however, egg is a perishable food, potentially losing quality if not handled properly...
BACKGROUND
Egg yolk is recognized for its excellent nutritional benefit and economic value; however, egg is a perishable food, potentially losing quality if not handled properly between the time from farm production to consumption. Knowledge of the changes of yolk lipid composition under an extreme storage condition close to vitelline membrane breaking, which results in an inedible condition for shelf-eggs, remains incomplete. Considering the complexity of yolk lipids, the architectural features of yolk lipids at high-temperature storage (30°C for 10 days versus fresh) were classified through lipidomics.
RESULTS
This strategy yielded 1508 features within the lipid database coupled with 74 significantly different lipids (P < 0.05, fold change > 1.2 or < 0.83), mainly triglycerides, phospholipids, and sphingolipids. Most of them were decreased after storage; for example, triglycerides were assumed to play a role as a 'buffer' to maintain the system stability during storage by balancing fatty acid saturation, which strongly reduces the egg edible value for humans. Furthermore, phospholipids, especially the highly unsaturated phosphatidylcholine, decreased significantly and were suggested to be the primary cause for the variation in yolk emulsifying properties and flavor.
CONCLUSION
Altogether, these results deriving from oxidation and lipolysis reactions enhance our understanding of lipid transformation and the biochemical mechanisms, at the molecular level, of the deteriorative process of the egg yolk. These findings may lay the foundation for identifying processes, including some modifications of the lipid composition of rations fed to laying hens, aiming to improve the long-term shelf-stability of shell eggs and egg products. © 2022 Society of Chemical Industry.
Topics: Animal Feed; Animals; Chickens; Chromatography, High Pressure Liquid; Egg Yolk; Eggs; Fatty Acids; Female; Humans; Lipidomics; Phospholipids; Triglycerides
PubMed: 35411552
DOI: 10.1002/jsfa.11916 -
Foods (Basel, Switzerland) Apr 2022The proteomic profiles of Silky fowl egg yolk (SFEY) and Leghorn egg yolk (LEY) were analyzed by bottom-up label-free liquid chromatography-tandem mass spectrometry...
The proteomic profiles of Silky fowl egg yolk (SFEY) and Leghorn egg yolk (LEY) were analyzed by bottom-up label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). From a total of 186 identified proteins, 26 proteins were found significantly differentially abundant between two yolks, of which, 19 were up-regulated and 7 were down-regulated in SFEY, particularly, vitelline membrane outer layer protein 1, transthyretin and ovoinhibitor were up-regulated by 26, 25, and 16 times, respectively. In addition, there were 57 and 6 unique proteins in SFEY and LEY, respectively. Gene Ontology (GO) revealed SFEY contained relatively more abundant protease inhibitors and coagulation-related proteins. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed differentially abundant proteins in SFEY may be actively involved in the regulation of the neuroactive ligand-receptor interaction pathway. This study provides a theoretical basis for the understanding of proteomic and biological differences between these two yolks and can guide for further exploration of nutritional and biomedical use of Silky fowl egg.
PubMed: 35407122
DOI: 10.3390/foods11071035