A congenital ciliated epithelial cyst on the stomach of a B6C3F1 mouse. (1/87)

Congenital anomalies of the alimentary tract are rare lesions in laboratory animals. We describe a congenital cyst attached to the greater curvature of the forestomach in a B6C3F1 mouse. The inner surface of the cyst was mostly covered with cuboidal or pseudostratified ciliated epithelium and was focally covered with the flat cuboidal epithelium. The base of the cyst appeared to be inserted between the layers of the outer longitudinal muscle layer of the forestomach, although no smooth muscle layer was evident in the free surface of the cyst wall. The cyst resembled duplication of the alimentary tract, as it was lined with ciliated epithelium and had developed at the greater curvature of the forestomach. Since the smooth muscle layer did not completely cover the whole wall and the cyst did not communicate with the gastric lumen, the cyst was not thought to be a standard duplication but rather a simple congenital cyst.  (+info)

Congenital malformations of the gallbladder and cystic duct diagnosed by laparoscopy: high surgical risk. (2/87)

Congenital anomalies of the gallbladder are rare and can be accompanied by other malformations of the biliary or vascular tree. Being difficult to diagnose during routine preoperative studies, these anomalies can provide surgeons with an unusual surprise during laparoscopic surgery. The presence of any congenital anomaly or the mere suspicion of its existence demands that we exercise surgical prudence, limit the use of electrocoagulation, and ensure that no structure be divided until a clear picture of the bile ducts and blood vessels is obtained. If necessary, perform intraoperative cholangiography to further define the biliary system. However, if the case remains unclear, or if laparoscopy does not provide enough information, open surgery should be considered before undesirable complications occur.  (+info)

Hedgehog signals regulate multiple aspects of gastrointestinal development. (3/87)

The gastrointestinal tract develops from the embryonic gut, which is composed of an endodermally derived epithelium surrounded by cells of mesodermal origin. Cell signaling between these two tissue layers appears to play a critical role in coordinating patterning and organogenesis of the gut and its derivatives. We have assessed the function of Sonic hedgehog and Indian hedgehog genes, which encode members of the Hedgehog family of cell signals. Both are expressed in gut endoderm, whereas target genes are expressed in discrete layers in the mesenchyme. It was unclear whether functional redundancy between the two genes would preclude a genetic analysis of the roles of Hedgehog signaling in the mouse gut. We show here that the mouse gut has both common and separate requirements for Sonic hedgehog and Indian hedgehog. Both Sonic hedgehog and Indian hedgehog mutant mice show reduced smooth muscle, gut malrotation and annular pancreas. Sonic hedgehog mutants display intestinal transformation of the stomach, duodenal stenosis (obstruction), abnormal innervation of the gut and imperforate anus. Indian hedgehog mutants show reduced epithelial stem cell proliferation and differentiation, together with features typical of Hirschsprung's disease (aganglionic colon). These results show that Hedgehog signals are essential for organogenesis of the mammalian gastrointestinal tract and suggest that mutations in members of this signaling pathway may be involved in human gastrointestinal malformations.  (+info)

The incidence of cardiac lesions in infants born with major gastrointestinal malformations in Northern Ireland. (4/87)

There is a recognised association between major gastrointestinal (GI) malformations and congenital heart disease (CHD). A retrospective study over 10 years involving 240 infants born with gastrointestinal malformations was conducted in the Royal Belfast Hospital For Sick Children (RBHSC). We felt it was important to look at the incidence of CHD diagnosed in the infants presenting to the tertiary referral centre in Belfast. Comparable figures for the incidence of CHD associated with major GI malformations was found in the literature.  (+info)

Multiple functional defects in peripheral autonomic organs in mice lacking muscarinic acetylcholine receptor gene for the M3 subtype. (5/87)

Muscarinic acetylcholine receptors consist of five distinct subtypes and have been important targets for drug development. In the periphery, muscarinic acetylcholine receptors mediate cholinergic signals to autonomic organs, but specific physiological functions of each subtype remain poorly elucidated. Here, we have constructed and analyzed mutant mice lacking the M(3) receptor and have demonstrated that this subtype plays key roles in salivary secretion, pupillary constriction, and bladder detrusor contractions. However, M(3)-mediated signals in digestive and reproductive organs are dispensable, likely because of redundant mechanisms through other muscarinic acetylcholine receptor subtypes or other mediators. In addition, we have found prominent urinary retention only in the male, which indicates a considerable sex difference in the micturition mechanism. Accordingly, this mutant mouse should provide a useful animal model for investigation of human diseases that are affected in the peripheral cholinergic functions.  (+info)

Cooperation of endoderm-derived BMP2 and extraembryonic ectoderm-derived BMP4 in primordial germ cell generation in the mouse. (6/87)

The primordial germ cells (PGCs) of the mouse are derived from proximal epiblast cells that are adjacent to the extraembryonic ectoderm during gastrulation. Previous studies have demonstrated that extraembryonic ectoderm-derived BMP4 and BMP8B are both required for PGC generation. Here we show that Bmp2, a member of the Dpp class of the Bmp superfamily, also plays a role in PGC generation. PGC number is significantly reduced in Bmp2 heterozygous and homozygous embryos at the N2 generation onto C57BL/6 background. Bmp2 homozygous embryos also have a short allantois and about 50% of them do not undergo normal chorioallantoic fusion. Using whole-mount in situ hybridization, we show that Bmp2 is primarily expressed in the endoderm of mouse pregastrula and gastrula embryos. Using a genetic approach, we further show that Bmp2 and Bmp4, but not Bmp2 and Bmp8b, have an additive effect on PGC generation. These results suggest that PGC generation in the mouse embryo is regulated not only by extraembryonic ectoderm-derived BMP4 and BMP8B, but also by endoderm-derived BMP2.  (+info)

Screening for foetal malformations: performance of routine ultrasonography in the population of the Swiss Canton of Vaud. (7/87)

OBJECTIVE: To determine the sensitivity of ultrasonography in screening for foetal malformations in the pregnant women of the Swiss Canton of Vaud. STUDY DESIGN: Retrospective study over a period of five years. METHOD: We focused our study on 512 major or minor clinically relevant malformations detectable by ultrasonography. We analysed the global sensitivity of the screening and compared the performance of the tertiary centre with that of practitioners working in private practice or regional hospitals. RESULTS: Among the 512 malformations, 181 (35%) involved the renal and urinary tract system, 137 (27%) the heart, 71 (14%) the central nervous system, 50 (10%) the digestive system, 42 (8%) the face and 31 (6%) the limbs. Global sensitivity was 54.5%. The lowest detection rate was observed for cardiac anomalies, with only 23% correct diagnoses. The tertiary centre achieved a 75% detection rate in its outpatient clinic and 83% in referred patients. Outside the referral centre, the diagnostic rate attained 47%. CONCLUSIONS: Routine foetal examination by ultrasonography in a low-risk population can detect foetal structural abnormalities. Apart from the diagnosis of cardiac abnormalities, the results in the Canton of Vaud are satisfactory and justify routine screening for malformations in a low-risk population. A prerequisite is continuing improvement in the skills of ultrasonographers through medical education.  (+info)

The Drosophila gap junction channel gene innexin 2 controls foregut development in response to Wingless signalling. (8/87)

In invertebrates, the direct communication of neighbouring cells is mediated by gap junctions, which are composed of oligomers of the innexin family of transmembrane proteins. Studies of the few known innexin mutants in Drosophila and C. elegans have shown that innexin proteins, which are structurally analogous to the connexins in vertebrates, play a major structural role as gap junctional core components in electric signal transmission. We show that Drosophila innexin 2 mutants display a feeding defect that originates from a failure of epithelial cells to migrate and invaginate during proventriculus organogenesis. The proventriculus is a valve-like organ that regulates food passage from the foregut into the midgut. Immunohistological studies indicate that innexin 2 is functionally required to establish a primordial structure of the proventriculus, the keyhole, during the regionalisation of the embryonic foregut tube, which is under the control of Wingless and Hedgehog signalling. Our genetic lack- and gain-of-function studies, and experiments in Dorsophila tissue culture cells provide strong evidence that innexin 2 is a target gene of Wingless signalling in the proventricular cells. This is the first evidence, to our knowledge, that an invertebrate gap junction gene controls epithelial tissue and organ morphogenesis in response to the conserved WNT signalling cascade.  (+info)