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Lutein in Neural Health and Disease
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
The human eye is embryologically derived from surface ectoderm, neural ectoderm, and mesoderm by the end of 3 weeks gestation. The neural ectoderm is the same tissue from which the neural plate and other brain tissues are derived. All the basic structures of the eyes are present by the sixth week of gestation.86 Lutein is present in infant eyes during early gestation and predominates in the macula up to ∼2 years of life.87,88 The developing newborn eye may be vulnerable to damaging blue light and oxidative damage,89,90 partly due to the relatively transparent lens of an infant, which can allow more damaging blue light to reach the retina.91 The central portion of the retina, the fovea, changes dramatically after birth and evidence has shown that the infant retina “ages” rapidly due to increased oxidative stress. For example, the accumulation of lipofuscin is most rapid in the first years of life.92,93 The photoreceptors of the retina, rods and cones, are important for visual transmission and may be particularly vulnerable to damage due to their high concentrations of polyunsaturated fatty acids, particularly docosahexaenoic acid.
Embryology of the Spinal Cord, Peripheral Nerves, and Vertebrae
Published in Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand, Pediatric Regional Anesthesia, 2019
Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand
In stage 9 (1.5- to 2-mm embryos, 19 to 20 d), the neural plate is curled (Figure 1.4). The embryonic disc elongates and the primitive streak and Hensen’s node appear to be carried caudad, since the cephalic area grows more rapidly. The embryo changes its shape, becoming first oval, then pear shaped. At this stage, the neural groove is in close contact with the notochord. Mesenchymatous cells of both sides of the notochord (paraxial mesoderm) show intense mitotic activity and differentiate as paired blocks of cells, the somites. This fundamental aspect of metamerism of the body does not occur in the paraxial mesoderm of the cephalic area.
Skeletal Embryology and Limb Growth
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Rick Brown, Anish Sanghrajka, Deborah Eastwood
The ectoderm forms the neural tube by a process called neurulation. In the midline, ectodermal cells become elongated, causing a relative thickening in that region (the neural plate). The two edges of the neural plate thicken to form the neural groove and neural folds. The neural tube forms by the fusion of the edges of these folds, which begins near the anterior end of the embryo and proceeds in anterior and posterior directions. The neural groove closes by the third week, except at its ends (the anterior and posterior neuropores), which normally close by the end of the fourth week. Failure of the anterior neuropore to close results in anencephaly, whilst neural tube defects (NTDs) are most commonly thought to arise from a failure of the posterior neuropore to close.
Fetal Tethered Spinal Cord: Diagnostic Features and Its Association with Congenital Anomalies
Published in Fetal and Pediatric Pathology, 2023
Xiaomei Yang, Shiyu Sun, Yizheng Ji, Yasong Xu, Li Sun, Qichang Wu
In this study, most TSC cases (22/26, 84.6%) were combined with congenital malformations, of which congenital neural tube defects (NTD) and multisystem complex congenital malformations were the most common. According to embryological development, any developmental disorder of the neural plate in the ectoderm and the notochord in the mesoderm can cause a malformation in the nervous system [15,16]. It is plausible to suggest and widely accepted that the common neural tube malformations associated with TSC, such as spina bifida aperta, spina bifida occulta, and severe hydrocephalus, restrict an upward shift of the spinal cord in the spinal canal, leading to TSC. Evidence suggests that prenatal determination of the conus medullaris position is important in spine-related diseases, contributing to the diagnosis, differential diagnosis, and prognosis [11–14]. Clinical observations demonstrate the association of low-lying conus medullaris and poor prognosis in patients with spina bifida aperta with myelomeningocele; in contrast, in a patient with spina bifida aperta with myelomeningocele and normal conus medullaris position, the developmental defects are completely reversible by surgery. Previous studies report on the important indicative function of abnormal conus medullaris position in the diagnosis of fetal spina bifida occulta with TSC: observing the conus medullaris position significantly reduces the possible misdiagnosis of fetal spina bifida occulta [11–14].
Acupuncture combined with moxibustion promote the recovery of spinal cord injury in correlation with Shh/Gli-1 signaling pathway
Published in The Journal of Spinal Cord Medicine, 2022
Li-Li-Qiang Ding, Song-Feng Hu, Xing-Wei He, Peng Zhang, Fen-Fen Zhao, Ting-Ping Liu, Qin Zhang, Fan He, Ying Yu, Peng Xiong, Chang-Kang Wang
After being anesthetized with ketamine (100 mg/kg body weight) combined with xylazine (25 mg/kg body weight), the rats were fixed on the operating table in a prone position. The skin and muscle of the spinal cord area (T8-T12 vertebral body) were incised and the spinous process and neural plate were exposed. The T10 spinous process and neural plate were removed by micro-rongeur forceps to expose the spinal cord. The spinal cord was set at the bottom of a stainless steel impact rod (diameter, 1.8 mm). A 10 g weight was released 8 cm vertically away from impact rod, the impact rod hit into spinal cord for about 1.5 mm. Then the incision was sutured. A successful SCI model was defined as a spinal cord with hemorrhage and edema, followed by contractions of the lower extremity, acutely swung tail, and flaccid paralysis. Rats of sham surgery group only removed spinous process and neural plate without spinal cord damaged. All SCI rats received assisted urination the bladder was gently pressed three times daily until the rat recovered the spontaneous urination.
Congenital Spinal Lipomatous Malformations. Part 1. Spinal Lipomas, Lipomyeloceles, and Lipomyelomeningoceles
Published in Fetal and Pediatric Pathology, 2020
Very early, the embryonic primitive streak forms the mesoderm and produces notochordal cells in Hensen’s node that probably induce the overlying ectoderm to thicken into the neural plate [17, 31]. The neural plate, covering much of the posterior early embryo, folds medially at its lateral borders with the embryonic ectoderm, possibly by compression from the ectoderm assisted by force generated by the mesoderm [41]. When the lips of the neural folds form at the ectoderm-neural plate borders and move medially to close dorsally and mesially, the primary neural tube is formed. The posterior neuropore at the caudal end of the primary neural tube closes at the level of the future S3–S5 vertebrae (Figure 2). The primary neural tube detaches (disjunction) from the ectoderm to complete primary neurulation. Failure of disjunction or a failure of posterior neuropore closure may cause open neural tube defects, the most common malformations of spinal dysraphism. The most common open neural tube defects over the spine include myelomeningoceles and craniorachischisis totalis [17, 40, 42–44].