Current perspectives of the signaling pathways directing neural crest induction

The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse

Is there any seasonal influence in spontaneous bleeding of intracranial aneurysms and/or arteriovenous malformations in Istanbul? A hospital based study

Principles: Despite many reports investigating the relationship of subarachnoid haemorrhage and seasonal variation in different parts of the world, there is no clear correlation. As far as we know this subject has not been reported from Istanbul yet. The purpose of this study is to determine if there is any correlation between season and spontaneous subarachnoid haemorrhage (SAH) caused by intracranial aneurysms and/or arteriovenous malformations (AVM) in Istanbul

Histopathological effects on epidural tissue of bolus or continuous infusions through an epidural catheter in ewes

P>This study was performed to evaluate the histopathological effects of epidural drug injection given either by intermittent bolus or continuous infusion through a catheter on epidural tissue. Fourteen ewes received intermittent bolus injections of morphine with bupivacaine, or a bolus of the same drugs followed by continuous infusion for 5 days. After 5 days, histopathological examination of the epidural space revealed mild to moderate inflammatory changes, and focal fibrosis surrounding the catheter in all ewes. The similarity of the inflammatory reaction in the control and drug treated groups seems to indicate that neither intermittent bolus or continuous infusion after a bolus dose caused histopathological changes in the epidural space beyond that caused by the catheter itself

The association of genetic polymorphisms of bone formation genes with canine hip dysplasia

Background: Canine hip dysplasia (CHD) is an orthopedic disorder characterized by abnormal laxity of the hip joint. It is considered multifactorial and polygenic and affects predominantly medium and large sized dog breeds. Aims: The aim of this study was to identify CHD associated polymorphisms in chromosomal regions on CFA19, CFA24, CFA26, and CFA34. Methods: Blood samples from 60 dogs of different breeds were collected and genotyped, including 46 cases and 14 controls. After sequencing and single nucleotide polymorphism (SNP) determination of the target regions, an individual SNP analysis with a chi(2) statistic was performed based on the comparison of allele frequencies in cases and controls. Results: A significant association was observed between CHD and a T/C SNP on CFA19, which harbors genes involved in bone metabolism. No other significant association was found in the study and previously identified SNPs cannot be validated as related to CHD. Conclusion: Further research is warranted to identify CHD-associated polymorphisms in order to develop a genotype-based diagnosis and selection approach