Sonographic Development of the Pericallosal Vascularization in the First and Early Second Trimester of Pregnancy.

BACKGROUND AND PURPOSE: Anomalies of the corpus callosum are rare. Routine scanning in midtrimester of the pregnancy often fails to identify defective development. The purpose of the study was to identify the pericallosal artery and all its main branching arteries during early gestation from the first trimester onward, to measure the length of the pericallosal artery during its development, and to establish a normal vascular map for each week of development. MATERIALS AND METHODS: We performed a single-center prospective, longitudinal clinical study in 15 patients between 11 and 22 weeks of gestation. The origin and course of the different blood vessels were identified. RESULTS: There was a linear association among gestational age, the biparietal diameter, and the length of the pericallosal artery. The curvature of the developing pericallosal artery increases linearly with the gestational age and biparietal diameter, and 4 variations of branching of the callosomarginal artery were observed. CONCLUSIONS: The pericallosal artery and its branches can be identified and measured from 11 weeks on, and the pericallosal artery takes its characteristic course. A defective course or an abnormal biometry of the pericallosal artery could be an early sonographic marker of abnormal development of the corpus callosum.

Sonographic detection of central nervous system defects in the first trimester of pregnancy.

The fetal central nervous system can already be examined in the first trimester of pregnancy. Acrania, alobar holoprosencephaly, cephaloceles, and spina bifida can confidently be diagnosed at that stage and should actively be looked for in every fetus undergoing first-trimester ultrasound. For some other conditions, such as vermian anomalies and agenesis of the corpus callosum, markers have been identified, but the diagnosis can only be confirmed in the second trimester of gestation. For these conditions, data on sensitivity and more importantly specificity and false positives are lacking, and one should therefore be aware not to falsely reassure or scare expecting parents based on first-trimester findings. This review summarizes the current knowledge of first-trimester neurosonography in the normal and abnormal fetus and gives an overview of which diseases can be diagnosed.

Outcome of 12 antenatally diagnosed fetal arachnoid cysts: case series and review of the literature.

OBJECTIVES: To investigate the natural history, associated abnormalities and outcome of 12 fetuses with arachnoid cyst diagnosed antenatally by ultrasound and magnetic resonance imaging and to compare the outcome with cases in the literature. METHODS: A retrospective study of all cases of antenatally detected fetal arachnoid cysts was performed in patients referred to a tertiary unit between 2007 and 2013. Associated abnormalities, pregnancy outcome and postnatal follow-up were analyzed. All papers about prenatally diagnosed arachnoid cysts, of the last 30 years, were evaluated (search terms in Pubmed: "prenatal diagnosis", "Arachnoid Cysts"). RESULTS: Fetal arachnoid cysts were diagnosed in 12 fetuses, 9 were females. The mean gestational age of diagnosis was 28 1/7 (range 19 1/7-34 2/7 weeks). A total of 9 cases were supratentorial, 3 were located in the posterior fossa. In 10 cases a fetal MRI was performed which confirmed brain compression in 4 out of 5 supratentorial arachnoid cyst. MRI did not reveal other malformations nor signs of nodular heterotopia. Only one fetus presented with additional major anomalies (bilateral ventricumomegaly of >20 mm and rhombencephalosynapsis) leading to a termination of pregnancy. Two neonates underwent endoscopic fenestration of the arachnoid cyst in the first week of life with no additional intervention in childhood. All but one (10/11) had a favorable postnatal outcome. This child suffered from visual impairment at autism was diagnosed at the age of 5. One child had a surgical correction of strabismus later in childhood. In one child the infratentorial arachnoid cyst regressed spontaneously on ultrasound and MRI in the postnatal period. CONCLUSIONS: The majority of arachnoid cysts in this series are of benign origin and remain stable. Based on the current series and the review of the literature, in the absence of other associated anomalies and when the karyotype is normal, the postnatal overall and neurological outcome is favorable. Large suprasellar arachnoid cysts however, may cause visual impairment and endocrinological disturbances. Rarely associated cerebral or cerebellar malformations are present. Modern postnatal management of suprasellar arachnoid cyst consists of endoscopic cystoventriculostomy.

Sequence evolution and escape from specific immune pressure of an HIV-1 Rev epitope with extensive sequence similarity to human nucleolar protein 6.

Antigen-specific immunity is crucially important for containing viral replication in human immunodeficiency virus (HIV)-1-infected hosts. Several epitopes have been predicted for the early expressed HIV-1 proteins Tat and Rev, but few have been studied in detail. We characterized the human leukocyte antigen (HLA)-B44-restricted Rev epitope EELLKTVRL (EL9) in an HIV-1-infected subject treated with antiretroviral therapy. Interestingly, a high sequence similarity was found between the EL9 epitope and the human nucleolar protein 6 (NOL6). However, this similarity does not seem to impede immunogenicity as CD8(+) T-cells, previously stimulated with EL9-pulsed dendritic cells, were able to specifically recognize the HIV-1 Rev epitope without cross-recognizing the human self-antigen NOL6. After the subject interrupted antiretroviral therapy and virus rebounded, mutations within the EL9 epitope were identified. Although the emerging mutations resulted in decreased or abolished T-cell recognition, they did not impair Rev protein function. Mutations leading to escape from T-cell recognition persisted for up to 124 weeks following treatment interruption. This study shows that the HLA-B44-restricted Rev CD8(+) T-cell epitope EL9 is immunogenic notwithstanding its close resemblance to a human peptide. The epitope mutates as a consequence of dynamic interaction between T-cells and HIV-1. Clinical status, CD4(+) T-cell count and viral load remained stable despite escape from T-cell recognition.

Fighting with the enemy's weapons? the role of costimulatory molecules in HIV.

HIV infection is characterized by a number of abnormalities in several components of the immune system. For example, during HIV infection, a massive decrease of CD4(+) T cells is observed, as well as a progressive depletion of naïve CD8(+) T cells. Furthermore, elevated numbers of apoptotic B and T cells are present in HIV-infected patients, and a systemic immune activation results in T-cell exhaustion. Finally, HIV infection is characterized by the presence of functionally impaired dendritic cells, with decreased expression of maturation markers, decreased secretion of cytokines and defects in antigen processing and presentation. All these characteristics result in the occurrence of non-functional cytotoxic T lymphocytes, that fail to control HIV-replication in most individuals during progressive disease. Costimulatory and co-inhibitory molecules are involved in the activation, differentiation and survival of several cell-types of the immune system. Each costimulatory receptor (generally expressed on effector cells) can conjugate with one or more specific ligands (expressed on antigen-presenting cells), which leads to an activation of intracellular signaling pathways inside the cells on which they are expressed. HIV infection is characterized by an aberrant expression of these molecules on cells of the immune system. Many of the immune deficiencies mentioned in the previous paragraph can be explained by abnormal expression of costimulatory molecules, and could consequently be overcome by interfering with their interactions. In this review, we give an overview of the functions and expression patterns of the receptor/ligand pairs of the tumor necrosis factor and the B7 super-families of costimulatory and co-inhibitory molecules in HIV-infected patients. We will also discuss possibilities for manipulating their signaling as a therapeutic anti-HIV tool.

Imaging the fetal central nervous system.

The low prevalence of fetal central nervous system anomalies results in a restricted level of exposure and limited experience-- for most of the obstetricians involved in prenatal ultrasound. Sonographic guidelines for screening the fetal brain in a systematic way will probably increase the detection rate and enhance a correct referral to a tertiary care center, offering the patient a multidisciplinary approach of the condition. This paper aims to elaborate on prenatal sonographic and magnetic resonance imaging (MRI) diagnosis and outcome of various central nervous system malformations. Detailed neurosonographic investigation has become available through high resolution vaginal ultrasound probes and the development of a variety of 3D ultrasound modalities e.g. ultrasound tomographic imaging. In addition, fetal MRI is particularly helpful in the detection of gyration and neurulation-- anomalies and disorders of the gray and white matter.

Receptor-mediated uptake of Legionella pneumophila by Acanthamoeba castellanii and Naegleria lovaniensis.

AIMS: Investigation of the attachment and uptake of Legionella pneumophila by Acanthamoeba castellanii and Naegleria lovaniensis, as these are two critical steps in the subsequent bacterial survival in both amoeba hosts. METHODS AND RESULTS: Initially, the mode of Legionella uptake was examined using inhibitors of microfilament-dependent and receptor-mediated uptake phagocytosis. Secondly, the minimum saccharide structure to interfere with L. pneumophila uptake was determined by means of selected saccharides. Bacterial attachment and uptake by each of the amoeba species occurred through a receptor-mediated endocytosis, which required de novo synthesis of host proteins. Legionella pneumophila showed a high affinity to the alpha1-3D-mannobiose domain of the mannose-binding receptor located on A. castellanii. In contrast, L. pneumophila bacteria had a high affinity for the GalNAcbeta1-4Gal domain of the N-acetyl-D-galactosamine receptor of N. lovaniensis. CONCLUSIONS: Our data pointed to a remarkable adaptation of L. pneumophila to invade different amoeba hosts, as the uptake by both amoeba species is mediated by two different receptor families. SIGNIFICANCE AND IMPACT OF THE STUDY: The fact that L. pneumophila is taken up by two different amoeba species using different receptor families adds further complexity to the host-parasite interaction process, as 14 amoeba species are known to be appropriate Legionella hosts.

Fetal hydrocephalus and intrauterine cerebral ventriculoscopy: an animal model.

OBJECTIVE: The aim of this study was to create an animal model of obstructive ventriculomegaly in the fetal lamb at 78 days of gestation by injecting maternal blood into the lateral ventricles under ultrasound guidance. METHODS: An endoscope of 1.2 mm housed in a 1.6-mm trocar was introduced into the dilated lateral ventricle. The lambs were sacrificed after delivery. RESULTS: All fetuses diagnosed with ventriculomegaly on ultrasound showed dilatation on the anatomical sections. The ventricles had a dilated aspect when compared to the controls. In 1 fetus the septum between the two ventricles was completely ruptured. Microscopically the ependymal cells were flattened and the cellular lining was disruptured. CONCLUSION: The model proved suitable for ventriculoscopic examination at 128 days of gestation. This should allow to elaborate further on therapeutic studies in this controversial area.

High-intensity focused ultrasound in the treatment of postpartum hemorrhage: an animal model.

OBJECTIVE: To investigate the use of high-intensity focused ultrasound (HIFUS) to reduce uterine artery blood flow in ewes in the postpartum period. METHODS: HIFUS was applied to the uterine arteries of seven ewes in the postpartum period. Arterial flow velocities were measured before and after the procedure at the site of HIFUS application (target), as well as 3 cm upstream and 3 cm downstream from the target. The uterine arteries were then removed for macroscopic and histological examination. RESULTS: Maximum flow velocities in the target area increased after the procedure by 350% and those upstream from the target decreased by 65%. Macroscopically, the vessel diameter was shown to have reduced at the site of HIFUS application. Microscopically, both the endothelium and media showed thermal lesions. Tissues surrounding the arteries were macroscopically and microscopically normal. CONCLUSION: Exposure of uterine arteries to HIFUS reduces the vessel diameter and thus induces a dramatic increase in the maximum flow velocities within the target area. HIFUS may have a role in the treatment of postpartum hemorrhage.

[Ultrasonographic features of orofacial clefts at first trimester of pregnancy: report of two cases]. / Aspects échographiques de fentes labio-palatines au premier trimestre de la grossesse. A propos de deux cas.

Fetal cleft lip and palate are now routinely diagnosed by prenatal ultrasound in the late first and second trimester of pregnancy. We report two cases of bilateral orofacial cleft diagnosed at 10 and 12.5 weeks of gestation by ultrasound. Ultrasound can replace invasive embryoscopy for the early diagnosis of facial cleft, based on specific sonographic signs in high risk patients.

Pregnancy outcome in fetuses with increased nuchal translucency and normal karyotype.

OBJECTIVE: This study was conducted to evaluate pregnancy outcome and mid- and long-term prognosis of cases with nuchal translucency > or =4 mm and normal karyotype. METHODS: Retrospective analysis of 160 cases who presented with a nuchal translucency > or =4 mm when the CRL was between 45 and 84 mm was undertaken. Cystic hygromas were excluded. When the karyotype was normal a detailed anomaly scan was performed at 20 to 24 weeks followed by serial ultrasound examination. Clinical examination of the neonates was performed by a paediatrician. Long-term follow-up was completed through a questionnaire filled in by parents, GPs and paediatricians. RESULTS: 160 fetuses had an NT > or =4 mm. 44.3% had an abnormal karyotype. Of the 55.7% with normal karyotypes, 74 % did not show any abnormalities on follow-up ultrasound scan. Mid- and long-term outcome was known in 91% of the cases. 6.4% had a malformation diagnosed only at birth. Among the normal neonates, 11.1% are considered to have a significant neurological handicap or orthopaedic problems at 12 to 72 months of age. CONCLUSION: In an unselected population, NT > or =4 mm is associated with a high incidence of chromosomal and non chromosomal abnormalities. Even when the fetal karyotype and serial ultrasound examinations are considered to be normal, the risk of fetal malformation and developmental delay should not be underestimated.

Prenatal diagnosis of brain abnormalities in Wolf-Hirschhorn (4p-) syndrome.

OBJECTIVES: Although there have been occasional reports of prenatal diagnosis of this syndrome, most cases are diagnosed postnatally. The objective was to evaluate the presence of brain abnormalities in the prenatal diagnosis of Wolf-Hirschhorn syndrome. METHODS: Prenatal ultrasound and MRI examination of the fetal brain were performed in a case of Wolf-Hirschhorn syndrome. A comprehensive review of Wolf-Hirschhorn syndrome reported between 1960 and 2000 in the literature was carried out. RESULTS: The late diagnosis of a growth-retarded fetus with normal amniotic fluid volume, normal Doppler and negative infection screen calls for a detailed examination of the fetal brain and heart. Multifocal white matter lesions and periventricular cystic changes, which are often attributed to perinatal distress, are possible prenatal features causing suspicion of 4p- syndrome in an IUGR fetus. CONCLUSION: Subtle abnormalities on ultrasound may suggest a chromosomal problem. Standard cytogenetics cannot always demonstrate a microdeletion. High-resolution banding and molecular analysis can help to confirm the diagnosis.

Sonographic diagnosis of spina bifida at 12 weeks: heading towards indirect signs.

Retrospective examination of ultrasound images obtained at 12 weeks of gestation in two fetuses with spina bifida demonstrated retraction of the frontal bones, resulting in an acorn-shaped head, the cerebral peduncles appearing parallel to each other. These craniocerebral signs may improve the accuracy of first-trimester diagnosis of spina bifida by sonography.