{"type": "FeatureCollection", "features": [{"id": "11454/87069", "type": "Feature", "geometry": null, "properties": {"updated": "2026-07-25T16:25:03Z", "type": "Report", "title": "Civciv embriyolar\u0131nda sekonder n\u00f6rulasyon evrelerinin histolojik olarak incelenmesi", "description": "Embargo90 SUMMARY Neurulation is the process of the neural tube formation. It can be investigated in two categories as primary and secondary neurulation. Primary neurulation takes place by formation of neural plate that starts with the proliferation of ectoderm, folding of the neural plate lateral edges, and raising of these folds and approaching and joining of them in the middle zone. Secondary neurulation, on the other hand, takes place in the caudal of the embryo and starts with the formation of medullar cord via grouping and densification of mesenchyme cells in the tail bud. Earlier investigations have usually covered the primary neurulation. In this study, however, process of secondary neurulation that forms through canalization of a massive group of cells is investigated. Secondary neurulation is studied in stage 15 of 55-hour chick embryo based on the Hamburger-Hamilton stages. After the removal of embryos from the eggs, they were dissected from their membranes and put into proper fixatives. Paraffin procedure was applied to a group of embryos for the purpose of light microscopy and histochemical studies. P.A.S. and Hematoksilen Eozin staining were done to some 2- micron sections taken from the paraffin blocks. In order to achieve a better resolution under the light microscopy, some chick embryos were prepared according to the electron microscopy sample preparation procedures, and epon blocks were prepared accordingly. Some 1 -micron sections taken from the epon blocks were stained by toulin blue. Finally, embryos were studied under the light microscopy, and their photos were taken. It was found out that secondary neurulation was formed via cavitation of the medullar cord that developed from the tail bud in the caudal of the chick embryo. Different from the primary neurulation, secondary neurulation in chick embryos has four stages: First, formation of a massive group of cells identified as medullar cord91 via joining of dorsal cells of the tail bud. Second, appearance of the edges of the area of the cells grouped and differentiation of the cells as central and peripheral cells. Third, cavitation between the central and peripheral cells. Fourth, joining of all lumens and formation of one central canal. Apoptotic cells were identified according to the histologic criteria in the secondary neural tube and tail mesenchyme formed during the time period investigated. It was thought that these apoptotic cells were used in the normal development and control of the cell number. Neural tube defects still stay an important health problem, even though the understanding of the neurulation has advanced in the last years. Neural tube closure defects in humans may give rise to neural tube defects known as spina bifida, vertebrate defects, and in the extreme cases paralysis. In addition, defects that come to existence during the secondary neurulation are observed in clinical cases as terminal miyelosistosel and thick filum terminale syndrome. Although, mechanisms in the molecular and cellular level are now understood better, understanding of the cell behavior is important in preventing the congenital malformations. Finally, It was declared that secondary neurulation is very important in the process of neural tube formation as neural tube formation is very important in the development of a normal human. Molecular level studies can help cure neurulation pathologies.", "keywords": ["Morphology", "Veterinary Medicine", "Veteriner Hekimli\u011fi", "Eggs", "Croquet", "fatty acids", "Pearl mullet", "kroket", "Kroket", "eggs", "chemical composition", "Fatty acids", "Morfoloji", "croquets.", "amino acids", "Su \u00dcr\u00fcnleri", "Fishes", "ya\u011f asitleri", "\u0130nci kefali", "yumurta", "kimyasal kompozisyon", "Yumurtalar", "Aquatic Products", "Amino acids", "Amino asitler", "Bal\u0131klar", "amino asitler", "Ya\u011f asitleri", "Chalcalburnus tarichi"], "contacts": [{"organization": "Duyar, H\u00fcnkar Avni", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/11454/87069"}, {"rel": "self", "type": "application/geo+json", "title": "11454/87069", "name": "item", "description": "11454/87069", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/11454/87069"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2020-12-29T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Croquet&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Croquet&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Croquet&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Croquet&offset=1", "hreflang": "en-US"}], "numberMatched": 1, "numberReturned": 1, "distributedFeatures": [], "timeStamp": "2026-07-26T10:09:21.360182Z"}