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Assessment of fetal brain abnormalities
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Cranium bifidum is classified into four types of encephaloschisis (including anencephaly and exencephaly), meningocele, encephalomeningocele, encephalocystocele, and cranium bifidum occultum. Encephalocele occurs in the occipital region in 70% to 80%. Acrania, exencephaly, and anencephaly are not independent anomalies. It is considered that dysraphia (absent cranial vault, acrania) occurs in very early stage and disintegration of the exposed brain (exencephaly) during the fetal period results in anencephaly. Encephalocele (Fig. 3) is often observed in the median section and in the parieto-occipital part. ABS should be differentiated from acrania during early pregnancy, because ABS has completely different pathogenesis from acrania/exencephaly. In cases of ABS, cranial destruction occurs secondary to an amniotic band; similar appearance is often observed.
Late-Gestation and Third Trimester
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
Multiple transgenic and mutant mouse models have been identified with these anomalies including open spina bifida, exencephaly, anencephaly and brain herniation (46), while ultrasounds of the human fetus have long allowed for prenatal diagnosis of these defects, with recent advances in in utero correction of anomalies, prior to birth (47). Consequently, applying ultrasound techniques to mice will allow for continued mouse models of diagnosis and intervention of these defects in utero. See Figs. 5.16–5.18.
Cocaine and the Fetus: Methodological Issues and Neurological Correlates
Published in Richard J. Konkol, George D. Olsen, Prenatal Cocaine Exposure, 2020
Cocaine has been implicated in the genesis of brain and eye malformations. Early in the epidemic, Bingol et al. reported skull defects, exencephaly, encephaloceles, and delayed ossification.72 Others noted a 12% rate of cerebral malformations among cocaine-exposed infants, comprised mostly of encephaloceles and skull defects.99 In a referral sample to a neurophthalmologist, Dominguez et al. described high rates of strabismus, nystagmus, and hypoplastic discs.100 Most infants also had cerebral malformations, strokes, or porencephaly. Many were exposed to illicit substances other than cocaine; only two infants with malformations were exposed exclusively to cocaine: one case of agenesis of the corpus callosum and one of septo-optic dysplasia. Other ocular anomalies noted among cocaine-exposed infants are delayed visual maturation, optic nerve hypoplasia, and persistent eyelid edema.'°’ Tortuous abnormally dilated iris vessels102 and a persistent hyperplastic primary vitreous with retinopathy of prematurity-like findings103 have also been linked to fetal cocaine exposure. Finally, other investigators in comparisons of 40 cocaine-positive infants with controls have found no differences in rates of congenital anomalies, optic disc and nerve abnormalities, or scleral and retinal hemorrhage.104 However, their small sample might have provided insufficient power to detect such an association.
Craniorachischisis with Exencephaly
Published in Fetal and Pediatric Pathology, 2021
Jessenia Guerrero, Debra S. Heller, Ada Baisre de Leon
Fetuses with craniorachischisis are characterized by anencephaly, however, occasionally exencephaly, which is recognized by the protruding brain tissue and absence of a calvarium [4], can be seen. The majority of cases of severe open neural tube defects present as anencephaly, with only a small fraction presenting with a disorganized, malformed brain tissue, which is exposed. They are both thought to be opposite ends of the most severe open neural tube defect, with most cases starting as exencephaly and the brain tissue dissolving while exposed to the amniotic fluid, resulting in the most common presentation of anencephaly [5]. Our case is very well preserved with both craniorachischisis and exencephaly, which was diagnosed as anencephaly by sonogram, with the classic microscopic appereance of exencephalic brain, showing ependymoplastomatous rosettes and haphazardly arranged inmature neural tissue [6].
Efficacy of Prenatal Ultrasound in Craniospinal Malformations According to Fetopathological and Postnatal Neonatological, Pathological Results
Published in Fetal and Pediatric Pathology, 2018
Fanni Rebeka Eros, Atene Simonyi, Zsolt Tidrenczel, Istvan Szabo, Janos Rigo, Artur Beke
Prenatal ultrasound was able to detect three quarter of craniospinal malformations before birth or abortion. Our results have confirmed that ultrasound tests play an important role in diagnosing CNS malformations but they do not always allow the detection of all brain and spine abnormalities. It has been concluded that anencephaly/exencephaly, spina bifida, hydranencephaly, ventriculomegaly, and sacrococcygealis teratome can be detected with great certainty in the fetus prenatally. In contrast, other CNS malformations, microcephaly and Arnold-Chiari malformation are found at a low rate. Being aware of the above is important for experts performing ultrasound tests, health professionals in providing genetic counselling and prenatal care and, also, neonatologists and paediatricians seeing newborns. During prenatal care, the expectant mother should be given adequate information about the efficacy of the examinations. If a malformation is detected postnatally, the couple should also be informed how reliably the specific malformation is detectable by prenatal sonography. It is recommended to use alternative test method (eg MRI) for certain disorders (eg agenesis / dysgenesis of corpus callosum). In postnatal and post abortion diagnostics the use of combined modalities (US and/or MRI and/or X-ray and/or pathology) is best utilized for confirmation.
Assessment of squalene eligibility in bettering some maternal and fetal disorders instigated by gamma irradiation of rats at mid gestation
Published in International Journal of Radiation Biology, 2018
Maha Fawzy Ibrahim, Nahed Abdelaziz
Noticeably, the embryonic lethality recorded in the present work was most obvious in the group of rats irradiated on the 10th day of gestation (Table 2), since it has been proved that the post-implantation death, during early organogenesis, reaches a maximum after acute radiation exposure on days 7–8 post-conception in mice and one day later in rats corresponding with day 16 post-conception in humans (Valentin 2003). This has been explained by various experimental studies showing that, during gastrulation, the mouse embryo becomes hypersensitive to DNA damage induced by irradiation. Accordingly, two major pathways can be activated in response to DNA damage namely, cell cycle arrest (which allows the cell to repair DNA damage before it becomes fixed as a mutation) or apoptosis (Heyer et al. 2000). Moreover, the prevalence of exencephaly as the most prominent neural defect among the surviving embryos (Group 3) (Table 2, Figure 2) might have resulted from the radiation-induced alteration in cholesterol level (Table 1) that affected the development of the nervous system (Tozawa et al. 1999). Similarly, a previous study has shown the prevalence of rat fetal macrocephaly following maternal (3Gy) whole-body gamma irradiation on the 10th gestational day (Rezk and Ibrahim 2006).