A combination insecticide at sub-lethal dose debilitated the expression pattern of crucial signalling molecules that facilitate craniofacial patterning in domestic chick Gallus domesticus.

Pesticides despite being agents that protect the plants and humans from noxious pests, are infamous for their potential to cause detrimental health issues in nontargeted species. In order to ascertain the latter, a set of experiments were conducted by exposing early chick embryos to a widely used combination insecticide (Ci, 50% chlorpyrifos and 5% cypermethrin). The results revealed a myriad of congenital defects pertaining to craniofacial development such as anophthalmia, microphthalmia, exencephaly as well as deformed beak and cranial structures. These teratological manifestations could be attributed to the Ci induced alteration in the titre of major regulators of neurulation and ossification. Therefore, the mRNA and/or the protein level expression pattern of genes which are reported to be involved in the craniofacial development were studied at selected time points of embryonic development. The analysis of the result showed that there have been significant alternations in the expression patterns of the signalling molecules such as SHH, WNTs, CDH1, CDH2, L1CAM, PAX6, HOX, PCNA, GLI3, BMP7, FGF8, GLIs, SOX9, RUNX2, DLX5, COL10A1, CASPASE3 etc. on embryonic days 2, 4 and/or 10. Concurrently, on day 10, whole-mount skeletal staining and biochemical estimation of hydroxyproline were carried out in the cranial tissues of the embryos. The overall result of the current study indicates that exposure to Ci during early development impede the crucial regulatory signals that orchestrate the morphogenesis of cranial neural crest cells thereby hindering the normal progression of neural tube and endochondral ossification which collectively lead to craniofacial dysmorphism in domestic chicks.

Fetal skeletal dysplasias: sonographic indices associated with adverse outcomes.

OBJECTIVES: To assess the utility of biometric indices and amniotic fluid volume in identifying fetuses with lethal skeletal dysplasia. METHODS: A review of pregnancies with sonographic diagnosis of skeletal dysplasia between January 1997 and March 2012 from a single institution was conducted. Biometric indices and amniotic fluid volumes were reviewed from the initial targeted sonograms and all subsequent examinations. Outcomes were verified in all cases. Pregnancies that resulted in fetal or neonatal death were considered to have lethal dysplasia, and those with survival to hospital discharge were considered to have nonlethal dysplasia. RESULTS: Of 45 fetuses with suspected skeletal dysplasia, 27 (60%) survived to hospital discharge; 9 (20%) died in the immediate neonatal period; 2 (4%) resulted in stillbirth; and in 7 cases (16%), pregnancy termination was elected. Those with lethal dysplasia were more likely to have hydramnios on initial detection than those who survived to hospital discharge (83% versus 27%; P < .01). Pregnancies complicated by lethal skeletal dysplasia had a significantly lower femur length-to-abdominal circumference ratio and were more likely to have a ratio below 0.16 than those with neonatal survival (91% versus 11%; P < 0.01). The lowest femur length-to-abdominal circumference ratio and the proportion with a ratio below 0.16 at any point in gestation were significantly different between those with lethal and nonlethal dysplasia (P< .01). As fetal size increased with advancing gestation, the relationship of sonographic parameters (eg, femur length-to-abdominal circumference ratio) became more pronounced. There was no infant survival when hydramnios was encountered at any point during gestation in the setting of a femur length-to-abdominal circumference ratio below 0.16. CONCLUSIONS: In our series, a femur length-to-abdominal circumference ratio below 0.16 in conjunction with hydramnios effectively identified fetuses with lethal skeletal dysplasia.

FAM111A mutations result in hypoparathyroidism and impaired skeletal development.

Kenny-Caffey syndrome (KCS) and the similar but more severe osteocraniostenosis (OCS) are genetic conditions characterized by impaired skeletal development with small and dense bones, short stature, and primary hypoparathyroidism with hypocalcemia. We studied five individuals with KCS and five with OCS and found that all of them had heterozygous mutations in FAM111A. One mutation was identified in four unrelated individuals with KCS, and another one was identified in two unrelated individuals with OCS; all occurred de novo. Thus, OCS and KCS are allelic disorders of different severity. FAM111A codes for a 611 amino acid protein with homology to trypsin-like peptidases. Although FAM111A has been found to bind to the large T-antigen of SV40 and restrict viral replication, its native function is unknown. Molecular modeling of FAM111A shows that residues affected by KCS and OCS mutations do not map close to the active site but are clustered on a segment of the protein and are at, or close to, its outer surface, suggesting that the pathogenesis involves the interaction with as yet unidentified partner proteins rather than impaired catalysis. FAM111A appears to be crucial to a pathway that governs parathyroid hormone production, calcium homeostasis, and skeletal development and growth.

Frank-ter Haar syndrome protein Tks4 regulates epidermal growth factor-dependent cell migration.

Mutations in the SH3PXD2B gene coding for the Tks4 protein are responsible for the autosomal recessive Frank-ter Haar syndrome. Tks4, a substrate of Src tyrosine kinase, is implicated in the regulation of podosome formation. Here, we report a novel role for Tks4 in the EGF signaling pathway. In EGF-treated cells, Tks4 is tyrosine-phosphorylated and associated with the activated EGF receptor. This association is not direct but requires the presence of Src tyrosine kinase. In addition, treatment of cells with LY294002, an inhibitor of PI 3-kinase, or mutations of the PX domain reduces tyrosine phosphorylation and membrane translocation of Tks4. Furthermore, a PX domain mutant (R43W) Tks4 carrying a reported point mutation in a Frank-ter Haar syndrome patient showed aberrant intracellular expression and reduced phosphoinositide binding. Finally, silencing of Tks4 was shown to markedly inhibit HeLa cell migration in a Boyden chamber assay in response to EGF or serum. Our results therefore reveal a new function for Tks4 in the regulation of growth factor-dependent cell migration.

Neural crest-specific loss of Prkar1a causes perinatal lethality resulting from defects in intramembranous ossification.

The cranial neural crest (CNC) undergoes complex molecular and morphological changes during embryogenesis in order to form the vertebrate skull, and nearly three quarters of all birth defects result from defects in craniofacial development. The molecular events leading to CNC differentiation have been extensively studied; however, the role of the cAMP-dependent protein kinase [protein kinase A (PKA)] during craniofacial development has only been described in palate formation. Here, we provide evidence that strict PKA regulation in postmigratory CNC cells is essential during craniofacial bone development. Selective inactivation of Prkar1a, a regulatory subunit of the PKA holoenzyme, in the CNC results in perinatal lethality caused by dysmorphic craniofacial development and subsequent asphyxiation. Additionally, aberrant differentiation of CNC mesenchymal cells results in anomalous intramembranous ossification characterized by formation of cartilaginous islands in some areas and osteolysis of bony trabeculae with fibrous connective tissue stabilization in others. Genetic interaction studies revealed that genetic reduction of the PKA catalytic subunit C(alpha) was able to rescue the phenotype, whereas reduction in Cbeta had no effect. Overall, these observations provide evidence of the essential role of proper regulation of PKA during the ossification of the bones of the skull. This knowledge may have implications for the understanding and treatment of craniofacial birth defects.

[Advances in the treatment of newborns with congenital malformations]. / Postepy w leczeniu noworodków z wadami wrodzonymi wymagajacymi operacji bezposrednio po urodzeniu.

Authors analyzed the type and the number of treated congenital malformations in 544 newborns operated between 1992-2001 in the Department of Paediatric Surgery in the Institute of Mother and Child. The patients were divided in the following groups: digestive tract defects, abdominal wall and diaphragm defects, neural tube defects, urinary track defects, craniofacial and brain defects and others anomalies occurring rarely. Most of the operations were preformed in the first 48 hours of life. Since 1995 special newborn transport, early cardiac surgery and neonatal intensive care have been introduced. Total mortality of operated newborns and death in particular groups were analyzed. The implemented elements caused a decrease in mortality from 36 to 13 percent. In the authors' opinion improvement in treatment results is due to earlier diagnosis and better understanding of pathophysiology of the defects, introduction of noninvasive pre- and postnatal diagnostics and establishment of centres specialized in neonatal surgery and intensive care.

Linkage of otopalatodigital syndrome type 2 (OPD2) to distal Xq28: evidence for allelism with OPD1.

Otopalatodigital syndrome type 1 (OPD1) is an X-linked semidominant condition characterized by malformations of the skeleton, auditory apparatus, and palate. Previous studies have established linkage to a 16-cM region of Xq27-q28. A proposed allelic variant of OPD1, termed "OPD2," is associated with a more severe, frequently lethal phenotype with visceral and brain anomalies in addition to skeletal, auditory, and palatal defects. We report linkage of the OPD2 phenotype to a 2-cM region of distal Xq28 in a Maori kindred, with a maximum multipoint LOD score of 3.31 between the markers DXS1073 and DXS1108. This provides support for allelism between OPD1 and OPD2 and reduces the size of the disease interval to 1.8-2.1 Mb. We also demonstrate that female carriers of this disorder exhibit skewed inactivation that segregates with the high-risk haplotype and may be inversely related to the severity with which they manifest features of the disorder.

Perinatal lethality and multiple craniofacial malformations in MSX2 transgenic mice.

MSX2 is a homeodomain transcription factor that has been implicated in craniofacial morphogenesis on the basis of its expression pattern during mouse development and the finding of a missense mutation (P148H) in humans affected with Boston-type craniosynostosis. We have generated transgenic mice carrying a 34 kb DNA fragment encompassing a human MSX2 gene encoding either wild-type or mutant (P148H) MSX2. Inheritance of either transgene resulted in perinatal lethality and multiple craniofacial malformations of varying severity, including mandibular hypoplasia, cleft secondary palate, exencephaly, and median facial cleft, which are among the severe craniofacial malformations observed in humans. Transgenic mice also manifested aplasia of the interparietal bone and decreased ossification of the hyoid. Transgene-induced malformations involved cranial neural-crest derivatives, were characterized by a deficiency of tissue, and were similar to malformations associated with embryonic exposure to ethanol or retinoic acid, teratogens that cause increased cell death. Together with previous observations implicating MSX2 expression in developmentally-programmed cell death, these results suggest that wild-type levels of MSX2 activity may establish a balance between survival and apoptosis of neural crest-derived cells required for proper craniofacial morphogenesis.

Prolonged general anesthesia for experimental craniofacial surgery in fetal swine.

A protocol utilizing high preoperative doses of altrenogest (Regu-Mate) and a "balanced" general anesthesia regimen consisting of isoflurane at subanesthetic doses supplemented with intravenous doses of sodium thiopental was developed to prevent preterm labor, minimize intracranial fetal cerebral edema, and decrease postpartum mortality of fetal swine after undergoing complex in utero craniofacial procedures. A total of 20 fetal piglets at 75% gestation were exposed to prolonged (> 3 h) anesthesia conditions of which 7 piglets were randomly selected to undergo experimental craniofacial procedures consisting of periosteal stripping of frontal and parietal bone segments with/without extensive coronal suture fusion procedures. Neither sows nor piglets were lost to anesthetic complications during the initial laparotomy or subsequent cesarean delivery. None of the sows experienced uterine sepsis or underwent preterm labor. The overall survival rate for all piglets exposed to prolonged anesthesia conditions was 95% at 4 weeks and 45% at 11 weeks after surgery. The experimental group's survival was 85.7% at 4 weeks and 28.5% at 11 weeks after surgery.