China
Africa
Explore chapters and articles related to this topic
Central Nervous System and Facial Development
Published in Mary C. Peavey, Sarah K. Dotters-Katz, Ultrasound of Mouse Fetal Development and Human Correlates, 2021
Mary C. Peavey, Sarah K. Dotters-Katz
Central nervous system malformations are common abnormalities detected prenatally. Measurement of the lateral cerebral ventricles is attainable in mouse and human species, and can detect ranges of ventriculomegaly. To date, mouse models have provided important insights into the pathogenesis of numerous human anomalies, including congenital and neonatal hydrocephalus (32,33), ventriculomegaly (34,35), cephalocele (36), holoprosencephaly (37), and Dandy-Walker malformation (38). See Figs. 4.13–4.22.
Neural Control of Adenohypophysis
Published in Paul V. Malven, Mammalian Neuroendocrinology, 2019
The median eminence is just one of several unique structures in the brain known as circumventricular organs (CVO). These organs, which are also called neurohemal structures, share a common vascular and ependymal organization, which is different from the rest of the brain. As the name denotes, these organs are all located adjacent to some part of a cerebral ventricle. The capillaries in circumventricular organs have a characteristic fenestrated endothelium that probably accounts for the blood-brain barrier being less restrictive in these organs than in most brain tissue. Circumventricular organs are also unique in that their ependymal cells are non-ciliated, whereas ependymal cells in most other regions are ciliated. The diagram in Figure 4-4 shows the location of four different circumventricular organs including the median eminence. The organum vasculosum of the lamina terminalis (OVLT) is located around the rostral projection of the third ventricle above the optic chiasma. The subfornical organ is located on the midline beneath the descending fornix and in contact with the choroid plexus of the third ventricle. The subcommissural organ lines the roof of the third ventricle beneath the posterior commissure and habenula. The three circumventricular organs not illustrated in Figure 4-4 are pars nervosa, pineal gland, and area postrema. The first two of these are covered in detail in Chapters 3 and 10, respectively. The area postrema is located in the roof of the fourth ventricle caudal to the cerebellum.
Spinal Defects
Published in Asim Kurjak, CRC Handbook of Ultrasound in Obstetrics and Gynecology, 2019
The fetal vertebral column should lie directly against the placenta or uterine wall. If there is a defect such as meningomyelocele, a sonolucent space-occupying mass is seen pushing the fetal vertebral column away from the wall of the uterus or placenta. Limb structures below the defect may be visualized with real time to see whether or not activity occurs. Theoretically, if there is a minor neural herniation, limb motion may occur, but where there is a greater degree of neural involvement, limb motion distal to the defect may be decreased.2 However, Campbell and Pearce3 observed fetuses with major dorsolumbar lesions to have apparently normal limb movements and have only observed one case of urinary retention in a fetus with spina bifida. Thus, the assessment has to be made on the extent of the structural defect and the presence or absence of large cerebral ventricles.
SCN1A as a therapeutic target for Dravet syndrome
Published in Expert Opinion on Therapeutic Targets, 2023
Another potential barrier to human trials is administration, given that in animal testing, these agents have been given via a single injection into the cerebral ventricles. Intrathecal injection is reasonably straightforward to arrange in humans but can become problematic if injections must be repeated frequently. Each lumbar puncture carries with it risks for headache, infection, bleeding, and persistent cerebrospinal fluid leak which could require treatment with blood patch, an invasive, painful procedure. Additionally, when comparing to spinal muscular atrophy, the prototypic neurological disease treated with ASOs, Dravet syndrome has some unique challenges. Spinal muscular atrophy patients typically have normal intelligence so older individuals can undergo intrathecal injection with only local anesthetic; however, because of the significant cognitive impairment, even adult Dravet patients would require sedation, which has associated risks.
Jing-an oral liquid alleviates Tourette syndrome via the NMDAR/MAPK/CREB pathway in vivo and in vitro
Published in Pharmaceutical Biology, 2022
Leying Xi, Xixi Ji, Wenxiu Ji, Yue’e Yang, Yajie Zhang, Hongyan Long
The pathogenesis of TS is associated with abnormal levels of excitatory amino acid neurotransmitters such as Glu, ASP, and GABA within the CSTC loop. An increase in the ratio of excitatory to inhibitory amino acids has been proposed to underlie the pathogenesis of neuropsychiatric disorders such as TS, autism spectrum disorder, and OCD (Aida et al. 2015). GABA is the main inhibitory amino acid neurotransmitter, therefore, an imbalance in the Glu/GABA ratio in the CSTC loop can lead to tic-like behaviour (Kanaan et al. 2017). However, reports on GABA levels in TS are inconsistent. It has been reported that GABA concentrations in the primary sensorimotor cortex is lower in TS patients than in healthy children (Puts et al. 2015). However, our previous results indicated that the levels of Glu and GABA in striatum were significantly higher in rats with TS than in control rats (Long et al. 2019b). CSF is a colourless and transparent liquid that fills in each cerebral ventricle. When lesions form in the CNS and the metabolism of nerve cells is disturbed, changes occur in the properties and composition of CSF. However, it is not clear if changes in the levels of amino acid neurotransmitters in the brain are consistent with changes in the levels of amino acid neurotransmitters in the CSF. To clarify this, we evaluated the levels of Glu, ASP, and GABA in both CSF and BV2 cells in this research.
B4GAT1 Gene Associated Congenital Muscular Dystrophy Presenting with Recurrent Severe Ventriculomegaly: Case Report and Review of Literature
Published in Fetal and Pediatric Pathology, 2022
Meenakshi Lallar, Ladbans Kaur, Meetan Preet, U. P. Singh
Ultrasound at 24 weeks showed diamniotic dichorionic twin pregnancy with severe ventriculomegaly. The lateral atrial width measured 30 mm, transcerebellar diameter measures 1.6 cm with the vermis length of 0.8 cm. The main landmarks of the fetal cerebral cortex seen radiologically at 24 weeks of gestation are represented by the Sylvian fissure and parietooccipital fissure [6]. In our case, there was non visualization of the Sylvian or parieto-occipital fissures (Figure 1(a,b)). Ultrasound-based diagnosis of severe ventriculomegaly, cerebellar and vermian hypoplasia with non-visualization of cerebral fissures and smooth brain (probably neuronal migration defects) was made. Given the above findings, the couple was counseled regarding possible etiology and poor prognosis and they decided to terminate the pregnancy. Both fetal autopsies were performed after informed consent. In both the twin male fetuses, the head circumference was increased (26 cm; >3SD). There were no other external anomalies or dysmorphism. There were no contractures or pterygia. On internal brain examination, the brain cortical surfaces were smooth with absent Sylvian and parieto-occipital fissures. The cerebral ventricles were dilated with lateral atrial width of 30 mm. The cerebellum measured 2 cm (transcerebellar diameter) which is less than the 3rd percentile for 24 weeks gestation; the vermian length along the sagittal plane was 1 cm (<3rd percentile for 24 weeks) (Figure 2). Histopathology was not done.