Showing posts with label Development. Show all posts
Showing posts with label Development. Show all posts

Thursday, August 8, 2013

Embryo development discovery

Barx Expression of the Barx1 gene (red) in early tooth development

Researchers have uncovered a novel mechanism they have termed ‘developmental stalling’, that might explain how errors in the development of human embryos are naturally corrected to prevent birth defects. 

In a study published in the journal, Proceedings of the National Academy of Sciences (PNAS), researchers from King’s College London’s Dental Institute demonstrate how a key developmental pathway, known as the ‘BMP pathway’ is responsible for ensuring organs correct themselves when growing abnormally in the womb. 

Humans are created from a fertilised egg, which develops into an embryo in a process called embryogenesis. The multitude of processes involved in this transition is extremely complex and prone to error. Errors in embryogenesis can lead to birth defects which occur in three to five percent of human births but, given the complexity of embryogenesis, this low figure is in fact surprising. 

To explore how potential defects are avoided, the team at King’s looked at different shaped teeth in developing mice embryos. They generated a mutation in a gene called Barx1 that is expressed during the development of molar teeth. However, the loss of Barx1 function did not result in abnormal molars as expected,  but rather molar development was ‘stalled’ by 24 hours during embryogenesis. 

This stalling was caused by a reduction in the BMP signalling pathway – a pathway that is already well-established as central to the developing embryo. During this stalling period, the BMP activity then steadily rose to eventually reach levels above the normal threshold, and molar development subsequently accelerated to catch up with the rest of the embryo. 

The researchers suggest that this organ autonomous stalling of development is a way for the embryo to correct errors in cell signalling that might otherwise lead to abnormal development. 

Professor Paul Sharpe from the Department of Craniofacial Development at King’s Dental Institute, said: ‘Developmental stalling may turn out to be a universal mechanism that allows developing tissues and organs to self-correct for any small errors in the complex signalling interactions that drive all developmental processes.

‘We now want to explore and understand the molecular mechanisms behind this process to enable us to see if this happens in the development of other organs. If we can understand how it works, it will give us vital insight into the development of birth defects in humans.’ 


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Sunday, August 4, 2013

Key gene in breast cancer development identified

Breast-cancer---istock1

Researchers at King’s College London have identified a gene involved in the development of breast cancer, which could lead to the earlier detection and treatment of the disease.

A new study, in collaboration with Institut d'Investigació Biomédica de Bellvitge (IDIBELL), has found that gene changes occur up to five years before the detection of breast cancer, paving the way for treatments aimed specifically at reversing changes in susceptible genes before cancer occurs.

Breast cancer is the most common cancer in the UK with around 50,000 people diagnosed each year.

Published today in Carcinogenesis, the study was based on a group of 36 identical twin pairs from TwinsUK, based at King’s, the biggest adult twin registry in the UK, where one twin had developed breast cancer and the other had not. Comparing DNA samples from each twin, collected before and after the diagnosis of breast cancer, as well as samples from breast tumours and breast cancer cell lines, the research team found significant chemical changes in around 400 sites in the affected twin. Of these, scientists identified the DOK7 gene was identified as most likely to be directly involved in the development of breast cancer. On average, these chemical changes took place five years prior to the diagnosis of breast cancer.

Identical twins such as those at TwinsUK are ideal for studies of this nature as theyshare 100 per cent of their genes. Therefore, any difference between twins is attributable to environmental factors or chemical changes to their genes. These chemicalchanges in the way genes are expressed is called epigenetics.

Crucially, the DOK7 gene identified in this study can be switched on and off epigenetically, says Professor Tim Spector from the Department of Twin Research & Genetic Epidemiology at King’s, who co-authored the research paper.

Professor Spector said: ‘The identification of the DOK7 gene offers possibilities for the prediction and treatment of breast cancer and other common illnesses such as diabetes, Alzheimer’s disease and arthritis. In the future screening of epigenetic changes in key genes followed by drug treatments could be commonplace. Our twin studies are a great way of detecting these small but important differences between sisters and we hope to explore many other diseases.’

Dr Manel Esteller, Head of Epigenetics at IDIBELL, said: ‘An epigenetic alteration associated with an increased risk of breast cancer can be detected in the sick twin before theclinical diagnosis.’ The next step for researchers will be identifying the exact function of the DOK7 gene.

Dr Esteller added: ‘We believe the DOK7 gene is a regulator of tyrosine kinases, an antitumor drug target already used for the treatment of breast cancer. If DOK7 performs this function, new studies to test drugs for tumours resistant to chemotherapy could take place in the future.’

Notes to editors

Professor Tim Spector is available for interview.

Please contact Jack Stonebridge, PR Coordinator at King’s College London, on 0207 848 3238 or email jack.stonebridge@kcl.ac.uk

View the Carcinogenesis paper.

For further information on King’s visit our ‘King’s in Brief’ page.

For more information on the Epitwin project visit the website.


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Saturday, June 29, 2013

Financial Development, Fixed Costs, and International Trade

Financial Development, Fixed Costs, and International Trade Skip Navigation

Contact Us My Basket My Account Review of Corporate Finance Studies About This Journal Contact This Journal Subscriptions View Current Issue (Volume 2 Issue 1 March 2013) Archive Search Oxford Journals EconomicsSocial Sciences Review of Corporate Finance Studies Volume 2 Issue 1 Pp. 1-28. Financial Development, Fixed Costs, and International Trade Bo Becker
Harvard Business School and NBER Jinzhu Chen
Chinese Academy of Social Sciences David Greenberg
BlackRock, Inc. Send correspondence to Bo Becker, Harvard Business School, Boston, MA 02163, USA; telephone: 617-496-5335. E-mail: bbecker{at}hbs.edu. Abstract Exports require significant up-front costs in product design, marketing, and distribution. These are intangible, firm-specific investments that are likely difficult to finance externally. We argue that a developed financial system can therefore facilitate exports. We test this prediction and find support for it. First, financial development is associated with more exports in industries in which fixed costs are high as well as to importers that require high costs. Second, trade dynamics are affected by financial development. In countries with better finance, exports are more sensitive to exchange rates. Finally, we predict and document that countries with more developed finance experience more volatile exports. (JEL F14, F36, G20, G30)

© The Author 2012. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com. « Previous | Next Article » Table of Contents This Article Review of Corporate Finance Studies (2013) 2 (1): 1-28. doi: 10.1093/rcfs/cfs005 First published online: November 28, 2012 » Abstract Full Text (HTML) Full Text (PDF) All Versions of this Article: cfs005v1 2/1/1 most recent Classifications Articles Services Alert me when cited Alert me if corrected Find similar articles Similar articles in Web of Science Add to my archive Download citation Request Permissions Citing Articles Load citing article information Citing articles via CrossRef Citing articles via Scopus Citing articles via Web of Science Google Scholar Articles by Becker, B. Articles by Greenberg, D. Search for related content Related Content Load related web page information Share Email this article Add to CiteULikeCiteULike Add to DeliciousDelicious Add to FacebookFacebook Add to Google+Google+ Add to MendeleyMendeley Add to TwitterTwitter What's this?

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