User:Z3333429

From Embryology

Lab Attendance

Lab 1: --Z3333429 (talk) 12:52, 6 August 2014 (EST)

http://www.ncbi.nlm.nih.gov/pubmed

PubMed

Lab 2: --Z3333429 (talk) 11:03, 13 August 2014 (EST)

Lab 3: --Z3333429 (talk) 11:12, 20 August 2014 (EST)

Lab 4: --Z3333429 (talk) 11:09, 27 August 2014 (EST)

Lab 5: --Z3333429 (talk) 11:32, 3 September 2014 (EST)

Lab 6: --Z3333429 (talk) 11:26, 10 September 2014 (EST)

Lab 7: Absent

Lab 8: --Z3333429 (talk) 11:29, 8 October 2014 (EST) (forgot to add signature for this lab, 24 September 2014)

Lab 9: --Z3333429 (talk) 11:26, 8 October 2014 (EST)

Lab 10: --Z3333429 (talk) 11:26, 15 October 2014 (EST)

Lab 11: --Z3333429 (talk) 11:51, 22 October 2014 (EST)

Lab 12: --Z3333429 (talk) 11:06, 29 October 2014 (EST)

Lab 1 Assessment

Article 1

Effect of vitamin D status on clinical pregnancy rates following in vitro fertilization[1]

Summary

Research was carried out to investigate the possible effect of vitamin D on human reproduction. The goal was to detect whether vitamin D levels Recent studies suggest that vitamin D may play a role in human reproduction. Our goal was to investigate whether there is a correlation between vitamin D levels and implantation and clinical pregnancy rates in infertile women following IVF.

Method

  • Participants in this investigation were 173 women undergoing IVF at Mount Sinai Hospital, Toronto, Ontatrio.
  • Serum 25(OH)D samples were collected within a week of oocyte retrieval from the patients.
  • The vitamin D levels of the participants were measured according to serum 25-hydroxy-vitamin D (25[OH]D) levels
  • Patients were classified in two categories according to serum levels of 25(OH)D: sufficient (≥ 75 nmol/L) or insufficient (< 75 nmol/L). Of the 173 patients, 54.9% presented with insufficient 25(OH)D levels and 45.1% has sufficient levels.
  • A comparison was made between patient demographics and IVF cycle parameters between sufficient and insufficient groups.
  • Clinical pregnancy, as identified by ultrasound following 4-5 weeks after embryo transfer; was the primary outcome measurement.

Findings

The research found that women who presented with sufficient 25(OH)D levels had significantly higher rates of clinical pregnancy per IVF cycle (52.5%) as compared to women with insufficient levels (34.7%). A higher rate of implantation was detected in the sufficient 25(OH)D group, however the results were not statistically significant. The research calls for further investigation the findings showed that vitamin D levels might be a predictor of clinical pregnancy and vitamin D supplementation could provide a simple and economical method of improving clinical pregnancy rates, not only in women undergoing IVF, but also across the board.

Reference

Kimberley Garbedian, Miranda Boggild, Joel Moody, Kimberly E Liu Effect of vitamin D status on clinical pregnancy rates following in vitro fertilization. CMAJ Open: 2013, 1(2);E77-82 PubMed 25077107

Alcohol consumption and quality of embryos obtained in programmes of in vitro fertilization

Article 2

Alcohol consumption and quality of embryos obtained in programmes of in vitro fertilization[2]

Summary

Alcohol consumption has been identified as one of the main stimulants that negatively affect the reproductive systems of both sexes. An investigation was carried out to analyse the effect of alcohol consumption of female participants on the quality of embryos obtained through IVF programmes.

Method

  • The study covered 54 women who received treatment due to infertility.
  • Of the 54 women who participated, 42.59% consumed alcohol. Records were examined of the class of embryos (A, B and C) that each woman presented in during treatment.
  • The database and statistical analyses were performed using computer software STATISTICA 7.1.

Findings

A statistically significant correlation was found between the occurrences of class B embryo in patients who consumed more than 25 grams of ethyl alcohol daily (72.72%). Women who consumed alcohol sporadically or those who abstained entirely from alcohol presented with 44.44% and 30% rates of class B embryos respectively. It was concluded that alcohol consumption (over 25 grams of ethyl alcohol) increases the likelihood of developing pooper quality embryos. More research should be carried out to investigate this further and it was suggested that active campaigns should be established to inform women of the negative affects of alcohol consumption on embryonic development.

Reference

Artur Wdowiak, Magdalena Sulima, Monika Sadowska, Bakalczuk Grzegorz, Iwona Bojar Alcohol consumption and quality of embryos obtained in programmes of in vitro fertilization. Ann Agric Environ Med: 2014, 21(2);450-3 PubMed 24959808

Effect of vitamin D status on clinical pregnancy rates following in vitro fertilization


References

  1. Kimberley Garbedian, Miranda Boggild, Joel Moody, Kimberly E Liu Effect of vitamin D status on clinical pregnancy rates following in vitro fertilization. CMAJ Open: 2013, 1(2);E77-82 PubMed 25077107
  2. Artur Wdowiak, Magdalena Sulima, Monika Sadowska, Bakalczuk Grzegorz, Iwona Bojar Alcohol consumption and quality of embryos obtained in programmes of in vitro fertilization. Ann Agric Environ Med: 2014, 21(2);450-3 PubMed 24959808


--Mark Hill These are good articles and well written summaries (5/5).

Lab 2 Assessment

Microscopic Field Image of GAD and GABA in Fetal Rat Lung Tissue.

Location of glutamic acid decarboxylase (GAD) and γ-aminobutyric acid (GABA) in fetal lungs of rats: Detection of antigens was used to identify the location of GAD and GABA on fetal lung tissue sections.[1]

Reference

  1. Narendranath Reddy Chintagari, Nili Jin, Li Gao, Yang Wang, Dong Xi, Lin Liu Role of GABA receptors in fetal lung development in rats. PLoS ONE: 2010, 5(11);e14171 PubMed 21152393

--Mark Hill This image and associated information meet the assessment criteria. I have fixed a few formatting issues with the figure referencing information. See the file history for changes. (4/5)

Lab 3 Assessment

Nicolas Leboulanger, Eréa-Noël Garabédian Laryngo-tracheo-oesophageal clefts. Orphanet J Rare Dis: 2011, 6;81 PubMed 22151899

Juan A Tovar Congenital diaphragmatic hernia. Orphanet J Rare Dis: 2012, 7;1 PubMed 22214468

Sharon Unger, Ian Copland, Dick Tibboel, Martin Post Down-regulation of sonic hedgehog expression in pulmonary hypoplasia is associated with congenital diaphragmatic hernia. Am. J. Pathol.: 2003, 162(2);547-55 PubMed 12547712


Congenital Diaphragmatic Hernia

Laryngo-tracheo-oesophageal clefts



--Mark Hill These are all good references, I would have also liked some explanation as to why they were relevant. (4/5)

Lab 4 Assessment

Cord Stem Cell Therapeutics

Human umbilical cord blood-derived mesenchymal stem cell transplantation for the treatment of spinal cord injury[1]

Summary

The aim of this study was to find investigate if the transplantation of Human Umbilical Cord Blood Mesenchymal Stem Cells (HUCB-MSC’s) can offer an effective therapeutic treatment of Spinal Cord Injuries (SCI) and provide evidence for clinical applications. Recent studies have shown that there are possible treatments for SCI. These studies have shown that changing the local environment following after SCI (through transplantation of umbilical cord blood stem cells and other various cells and tissues) can aid in regenerating injured nerve axons and lead to functional restoration of SCI. In this study, HUCB-MSC’s were transplanted into rat models for the treatment of SCI and the therapeutic effects were evaluated through the observed behaviour and histological changes shown in the rats.

Method

  1. HUCB was retrieved from consenting donors from the Departments of Gynaecology and Obstetrics at the First and Third Affiliated Hospitals of Zhengzhou University and Zhengzhou People’s Hospital (Zhengzhou, China). The HUCB samples were screened against the hepatitis B virus.
  2. 46 adult female Wistar rats were used from the Experimental Animal Center of Henan (Zhengzhou, China). The rats were kept in a pathogen-free room at 25°C and humidity of 45% humidity and were 250-280g in weight.
  3. The Allen’s method (laminectomy of the spinous process and vertebral plates of T8-T10, exposing the dorsum of the spinal cord) was used to create the SCI rat models. After the exposing of the spinal cord at T-8-T10 a weight was dropped to simulate SCI and then the rats were separated into three groups: the injury group (received no treatment following injury), the control group (treated with saline) and the transplantation group (treated with HUCB-MSC suspension).
  4. The HUCB cells were isolated and screen for viability then cultured.
  5. The cultured HUCB-MSC’s were collected and diluted then the suspension was injected at the SCI site of the rat models. The same procedure was carried out on the control group using physiological saline.
  6. Following transplantation, locomotor ratings were obtained from the control and transplant groups at two and four weeks. Histological changes were observed via samples collected at week one and four. These samples were then underwent statistical analysis.

Findings

Following treatment, the transplantation group displayed recovery of spinal nerve function and immunohistochemistry identified that there was production of novel nerve cells at wee four. These findings suggest that transplanting HUCB-MSCs help the functional recovery of the damaged of spinal cord nerves in rats with SCI.

Reference

  1. Bingzhou Cui, En Li, Bo Yang, Bo Wang Human umbilical cord blood-derived mesenchymal stem cell transplantation for the treatment of spinal cord injury. Exp Ther Med: 2014, 7(5);1233-1236 PubMed 24940417

Vascular Shunts

Foramen Ovale: located in the interatrial septum of the heart, allows blood to travel from the right atrium to the left atrium. Becomes fossa ovalis postnatally.

Ductus Venosus: located within the liver, becomes ligamentum venosum postnatally and allows blood from the umbilical vein to bypasses the liver and enter directly into the IVC.

Ductus Arteriosus: located within the aortich arch, allows blood to pass from the pulmonary artery into the descending aorta allowing blood from the right ventricle to bypass the non-functional lungs of the fetus. Postnatally it becomes the ligamentum arteriosum.

--Mark Hill Good (5/5)

Lab 5 Assessment

Newborn Respiratory Distress Syndrome (Hyaline Membrane Disease)

Newborn Respiratory Distress Syndrome (NRDS), also known as Hyaline Membrane Disease is characterised by the lack of or inability to synthesise surfactant in the premature lung of neonates.

The incidence of NRDS occurs in babies suffering form immature lung development, usually from premature birth with increased severity and incidence in correlation to decreased gestational age [1]. Preterm births do not allow for full lung maturation of the preterm infant due to process in which the respiratory system forms (from upper respiratory tree to lower). Type II Pneumocytes secrete surfactant into the alveoli, reducing surface tension and thus preventing the collapse of the alveolus – they are the last respiratory cells to differentiate. Preterm infants usually lack Type II Pneumocytes in their lung tissue causing the instability of their alveoli, oedema from immature alveolar capillaries and hyaline membrane formation[2].

NRDS mostly occurs in preterm neonates but can occur in post-term and term babies for a variety of reasons including:[3]

  • Intrauterine Asphyxia – commonly caused by wrapping umbilical cord around the neck of the neonate, impairing development[1]
  • Maternal diabetes – high levels of insulin can delay surfactant synthesis[4]
  • Multiple pregnancy (twins, triplets etc) – associated with high rates of preterm births and resulting lung immaturity [4]
  • Rapid labour, fetal distress, placenta previa, preeclampsia, placental abruption – that impair lung maturation in final stages of pregnancy [4]
  • Preterm Caesarean delivery – not allowing for lung maturation[5]
  • Genetic abnormalities that impair surfactant synthesis (ABCA3)[6]
  • Meconium Aspiration Syndrome (MAS) - damage to lower respiratory epithelium after aspiration of Meconium in amniotic fluid [7]

References

  1. 1.0 1.1 M C Hart Current concepts on respiratory distress syndrome in the newborn (hyaline membrane disease). Can Fam Physician: 1970, 16(11);64-7 PubMed 20468585
  2. Hyaline membrane disease. Br Med J: 1967, 1(5531);1-2 PubMed 6071188
  3. A Kumar, B V Bhat Epidemiology of respiratory distress of newborns. Indian J Pediatr: 1996, 63(1);93-8 PubMed 10829971
  4. 4.0 4.1 4.2 Rui Deng, Bin-Zhi Tang, Hua Liu, Yi Qu, De-Zhi My [Risk factors on the occurrence and prognosis of neonatal hyaline membrane disease]. Sichuan Da Xue Xue Bao Yi Xue Ban: 2010, 41(4);688-91 PubMed 20848797 Cite error: Invalid <ref> tag; name "PMID20848797" defined multiple times with different content Cite error: Invalid <ref> tag; name "PMID20848797" defined multiple times with different content
  5. Hind Beydoun, Khalid A Yunis, Mustapha Khogali, Ihab Usta, Hala Tamim, National Collaborative Perinatal Neonatal Network Caesarean route of delivery and hyaline membrane disease: a hospital-based case-control study in Greater Beirut. Paediatr Perinat Epidemiol: 2003, 17(4);363-8 PubMed 14629318
  6. Sergey Shulenin, Lawrence M Nogee, Tarmo Annilo, Susan E Wert, Jeffrey A Whitsett, Michael Dean ABCA3 gene mutations in newborns with fatal surfactant deficiency. N. Engl. J. Med.: 2004, 350(13);1296-303 PubMed 15044640
  7. M C Klingner, J Kruse Meconium aspiration syndrome: pathophysiology and prevention. J Am Board Fam Pract: 1999, 12(6);450-66 PubMed 10612363

--Mark Hill Very Good (5/5)

Lab 7 Assessment

Endocrine Development

The signalling of Gonadotropin-releasing hormone (GnRH) is responsible for regulating the actions of the gonads. The experiments in this study show that luteinising hormone expressing gonadotropes express the GnRHR and that increases in the secretion of luteinising hormone encourages gonadotropes expressed through follicle-stimulating hormone to develop. A functional role of GnHRH was suggested because removal of GnRHR cells increased the number of GnRH neurons in the hypothalamus meaning that it played a role in defining the amount of GnRH neurons present.[1]


This study was carried out on mice models where GnRHR cells were ablated to reveal the functional role in the embryonic development of the reproductive axis. The study suggests that luteinising gonadotropes acts as target cells for GnRH neurons in the forebrain and that maturation of follicle-stimulating hormone gonadotropes is dependent on the increased secretion of luteinising hormone. The method in which gonadotropes in the anterior pituitary gland mature was revealed as GnRH neurons migrate to the forebrain in the first step, secreting GnRH at this point. This is followed by the expression of GnHRH by the luteinising hormone gonadotropes. [1]


Tooth Development

The following embryonic layers and tissues contribute to the development of the teeth: The ectoderm of the first pharyngeal arch and neural crest, and ectomesenchymal cells.


  1. Odontoblasts - mesenchymal cells derived from the neural crest responsible for the secretion of predentin which calcifies to form the dentin if the teeth.
  2. Ameloblasts - cells derived from the differentiation of pre-ameloblasts from inner enamel epithelium. Responsible for he production if enamel.

--Mark Hill Good endocrine, tooth could have been clearer (4/5)

References

  1. 1.0 1.1 Shuping Wen, Wei Ai, Zahara Alim, Ulrich Boehm Embryonic gonadotropin-releasing hormone signaling is necessary for maturation of the male reproductive axis. Proc. Natl. Acad. Sci. U.S.A.: 2010, 107(37);16372-7 PubMed 20805495

Lab 8 Assessment

Embryonic Development of Testes

The gonads are derived from three sources during embryonic development:

  • Mesothelium
  • Underlying mesenchyme
  • Primordial germ cells: undifferentiated germ cells

Week 3: During week 3, the primordial germ cells migrate towards the primitive streak.

Week 5: Proliferation of the mesothelium and underlying mesenchyme occurs during week 5 of development and the gonadal ridge begins to form as a bulge on the medial region of the mesonephros. At this stage of development the gonadal cords begin to grow into the underlying mesenchyme. The gonadal structure at this stage of development is sexually indifferent.

  • Testes will form in the development of an XY embryo.

Week 6: Further migration of the primordial germ cells to the junction of the hindgut and yolk sac and then onto the gonadal ridge occurs at week 6. The differentiation of the primordial germ cells then begins at gametogenesis. Supporting cells are differentiated into Sertoli cells via the presence of sex-determining region Y gene – a protein-coding gene of the Y chromosome. Sertoli cells:

  • Involved in the differentiation of the male gonad
  • Secrete anti-Mullerian hormones – involved in the differentiation of the internal genital organs, ducts and gonads.
  • Differentiate sex-hormone-secreting cells into Leydig cells - release testosterone.
Transverse section of pig testicle revealing seminiferous tubules (derived from testis cords) and rete testis (derived from mesonephric tubules)

The gonadal cords begin differentiate into seminiferous cords or testis cords and this is controlled by the Y chromosome via testis-determining factor (TDF).

Week 7: At week 7 the testes begin to develop. Mullerian duct inhibitory factor is responsible for the obliteration of the paramesonephric duct and the mesonephric duct (Wolffian duct) begins to differentiate when acted upon by testosterone produced by the Leydig cells.

In these final stages of embryonic development, the male gonads have differentiated into two main parts:

  • Mesonephric duct: differentiates into the epididymis with the portion of the mesonephric duct lying outside of the gonad becoming the ductus deferens. The rete teste are formed from the mesonephric tubules growing towards the medullary sex cords.
  • Testis cords: containing the Sertoli cells and germ cells. In fetal development this will further differentiate into the seminiferous tubules – the area responsible for the production of spermatozoa during puberty in males.

References

Image of transverse section of pig testicle:

Keith, A. (1902) Human Embryology and Morphology. London: Edward Arnold.

Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic Textbook" and "Historic Embryology" appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms and interpretations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

--Mark Hill Where are the sources for your testis development summary. (4/5)

Lab Assessment 9

Renal Group

This page was well done and the introduction gave a clear insight into what the page was going to present. The strong point of this page was the descriptions of the developments the organs of the renal system. There were plenty of images to support the information in this section of your page that complimented the text and made it easier to read. The ‘Current Research’ section was another strong point and made the page really interesting because of the relevance to the rest of the text. I think this section in particular could spark the audience’s interest in this page. There seems to be plenty of references for each section and I think this is another real strong point of your page.

The weak point in terms of information was the ‘Historic Findings’ section. The individual in my group in charge of the ‘Historic Findings’ section found information in ‘Historic Embryo’ tab and if your group is unaware of this resource it may help. The ‘Abnormalities’ section does not yet seem to be completed and I think some of the abnormalities need to text written under their titles and some more images would make this section more interesting.

In terms of the organisation of this page, the strong point is the breaking up of the development into organs. It was a wise mood because it broke the text up into easy to understand segments with a good level of detail. The references still need to be organised particularly in the ‘Abnormalities’ section but I am sure this is something that will be handled during the finishing stages of the project. Overall, the page has its strong points and there are only some small issues that need to be rectified to make this page perfect.

Gastrointestinal Group

I think that the ‘Deformities’ section should be renamed to ‘Abnormalities’ and I am not sure if that is because it is the correct term but every lecture and similar page on the Embryology wiki uses the term ‘abnormality’ to describe abnormal developments. The page also needs to be more referenced more in some areas (e.g. the possible causes of Gastroschisis section) so as to allow your audience to read more into the text you have presented and give some citations to your information. Some sections are also suffering from a lack of information (e.g. ‘Recent Findings’ – more articles and ‘Abnormalities’ – more abnormalities) and I think some more research would definitely rectify these weak points.

I really liked the use of your own drawings in some of the sections and I think this demonstrates that you understand the concepts. My only criticism is that the images are a bit difficult to interpret because the colours are really hard to see against a white background. It would be good if you included some images from scientific literature as well to give more links to scientific papers.

Overall the page needs some more work and I think some more research and referencing will definitely go a long way in making this page better. You have the basic scaffold for you page and you only really need to develop some more detail in these areas.

Genital Group

The definite strengths of this page are the ‘Historic Findings’, ‘Current Models and Findings’ and ‘Abnormalities’ sections. They have plenty of detail and are well referenced but could benefit further with the addition of more images (some historic images would really make the ‘Historic Findings’ section even better). The ‘Historic Findings’ section would also be easier to follow if it were broken up (perhaps by using dot points or tables). Some of the uploaded images need captions to help explain them to the audience.

The attempt to tabulate the information in the ‘Development’ section of this page is a good way of presenting the text and makes it easier to understand. It needs to be completed and supported by more images. The inclusion of the video is also a great addition to this page but it does suffer from a lack of explanation. A brief explanation of the video or some time links in your table would make it easier for the audience to understand.

Overall your page has some great detail and it is apparent that a lot of research has been carried out to give plenty of citations to your text. An introduction to your page would be a great asset as it would introduce your page to the audience and give a general overview of what this page is presenting.

Integumentary Group

The introduction to this page offers a brief insight into the information presented in this wiki and is a good way to start your page. In the ‘Developmental Overview, the use of dot points to break up the text is a great way of presenting the information in conjunction with the table. The table is a really good piece of work and the images make it really interesting addition to the page.

The ‘Recent Findings’ section contains a good selection of articles but I think it could benefit from a brief description of each paper to reveal the relevance of the studies. The ‘Historic Findings’ section is well written but could also be improved by including some historic images to make it more interesting.

Overall this page is really well written with plenty of detailed text. The strong point of this page is the ‘Abnormalities’ section - it has great information and really good images to support it. It could be made even better if some more abnormalities were included. This page also benefits from its neat presentation and plenty of references.

Endocrine Group

The breaking down of this system into organs is a real strong point of this page and there is plenty of information under each of these subheadings. The page could benefit from a ‘Current Findings’ section or perhaps by including relevant articles under each organ.

The text in this page is great but it could really benefit from the inclusion of some more images to support the information. I can see that your group did plenty of research but in text citations need to be included with your text with a ‘References’ section at the bottom of the page to stop the reference lists scattered along the page from interrupting the flow of your page.

Overall the page is definitely well resourced and has plenty of detailed text. Along with the inclusion of images and some minor improvements with the organisation of your text, this page will become a very good finished product.

Neural Group

The page had plenty of detail in some of the sections especially in the ‘Abnormalities’ section. This section in particular could benefit from the use of in text citation to support the text and some images to give a visual representation of the information. It is clear that it is not yet finished so it when the rest of the abnormalities are completed I think that this could be a strong point of your page.

The ‘Current Research Models and Findings’ section has a good selection of articles but some subheadings need to be explained (e.g. ‘Future Research’). If possible, it might be beneficial to include some images break up this section but the summaries of most subheadings were very good. I think this page needs a ‘Historic Findings’ heading with the relevant information. A good place to start is to look under the ‘Historic Embryo’ tab for information.

Overall this page contained some good information but still needs some work. Focus on including a ‘Historic Findings’ subheading and in text citations to support your text.

Musculoskeletal Group

I think this page needs a lot of work in improving the overall layout. First, I think the page would benefit from a more formal introduction that introduces the content of the page in a way that is helpful to your audience. The age could also be improved by breaking it up into ‘Development’, ‘Historic Findings’, ‘Current Research Models and Findings’ as well as the Abnormalities section already included to make it flow better.

The text in under the ‘Molecular and Cellular Reputation of Fetal Myogenesis’ is really good but it is appears as a large slab of information that would be better presented with dot points to break it up and images to make it more interesting. The Abnormalities section is well written but is very brief. This section could be improved by including more abnormalities and the appropriate images.

Overall there is a lot of work to be carried out for this page but I understand that this is a smaller group. Perhaps breaking the work up into those smaller headings mentioned will help you split the work evenly. When all the text is uploaded, make sure that there is an effort to include in text citations to support all your information and images to make the page interesting. Try to avoid writing big slabs of information – tabulate or use dot points to break up large portions of text.

--Mark Hill Good peer feedback (8/10)

Lab Assessment 10

Genes and signalling networks regulated during zebrafish optic vesicle morphogenesis.[1]

SUMMARY: Mutant zebrafish models were used to find the Rx3-regulated gene sequence involved in the patterning of the early eye. It is understood that a single family of genes is vital in the programming of the DNA sequence responsible for retinal (Rx) transcription factors. The exact gene cascades that vertebrate eye morphogenesis rely on are poorly defined and mutations in the human retinal homeobox gene (RAX) have obvious clinical relevance due to their significance in the occurrence of abnormalities such as anophthalmia and microphthalmia.

METHOD:

  • AB Zebrafish were screened for heterozygous Rx3 mutations and were subsequently mated.
  • These embryos produced from these matings were grown to the 8-somite stage of development.
  • A dissecting light microscope was used to distinguish the embryos based on their morphologies. They were separated into eyeless mutants and eyed specimens labelled “normal’ and “wild-type” phenotypes respectively.
  • Three normal replicates and one wild-type replicate were collected and stored until processing.
  • The RNA was isolated with the use of a RNA extraction kit and a nanodrop spectrophotometer was used to measure the levels of RNA in the samples. The RNA integrity number was kept constant (at between 8 and 8.8 units) with the use of a Bioanalyser.
  • The RNA samples were organised in cDNA libraries using RNA sequencing kits.
  • The RNA sequences were mapped to the zebrafish genome and this data was used to predict the function of novel genes.
  • Gene counts were performed and compared to human homologs and human diseases with a known aetiology were linked to the zebrafish homologs.
  • In Rx3 mutants, the genes hmxl and six7 were analysed and in situ hybridisation was carried out on these wild-type zebrafish embryos.

RESULTS: Rx3-regulated genes were recognised using RNA sequencing and were found to play a role in optic vesicle morphogenesis within the wild-type phenotype. It was found that gene communication had occurred during the early eye development and hub genes (genes strongly connected via cross-talk) were found to express more changes between Rx3 mutants and normal phenotypes. The down regulation of hub genes in Rx3 mutants show the precursors for eye development and human eye disorders: homeodomain transcription factors and retinoid signalling mediators.

CONCLUSION: The zebrafish models displaying Rx3-regulated genes showed that Rx3 was responsible for optic vesicle morphogenesis as well as the expression of homeodomain transcription factors and retinoid signalling genes.

REFERENCES

  1. Jun Yin, Maria E Morrissey, Lisa Shine, Ciarán Kennedy, Desmond G Higgins, Breandán N Kennedy Genes and signaling networks regulated during zebrafish optic vesicle morphogenesis. BMC Genomics: 2014, 15(1);825 PubMed 25266257

--Mark Hill Excellent (5/5)

Lab 11 Assessment

Efficient Generation of Myelinating Oligodendrocytes from Primary Progressive Multiple Sclerosis Patients by Induced Pluripotent Stem Cell[1]

This study attempted to develop an affective and efficient method of deriving oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes from induced pluripotent stem cells (iPSCs). There is hope that this method will pave the way for treatment of progressive Multiple Sclerosis (MS) using neuroprotective and remyelinating techniques. Adherent cultures of Human Embryonic Stem Cells (hESC) and Induced Pluripotent Stem Cells (hiPSC) were induced to neural differentiation using dual SMAD and treated with retinoids from the onset of differentiation, produced an increase in OLIG2 progenitors and oligodendrocyte progenitor cell (OPC) yields. The strategies used in this study were also able to produce oligodendrocytes differentiation from neural iPSCs at significantly faster rate than previous studies had demonstrated.

The study also revealed that he methods used were capable of producing iPSCs from progressive MS patients that were viral and integration free and that differentiates efficiently into oligodendrocytes. These OPCs were shown to be fully functional and free of abnormalities when incorporated into mouse models where OPCs differentiated into mature oligodendrocytes and remyelinate axons. These findings in particular demonstrate a proof of concept for transplantation of iPSC derived neural cells into patients for the development of future cell-replacement therapies. This technology may also provide a valuable insight into the disease pathogenesis of neurodegenerative diseases and offer the platform to study drug treatments for diseases such as MS and Amyotrophic Lateral Sclerosis in the hope that they can produce attenuated rates of decline in these patients. There is a need for future studies that compare the potential differences between iPSCs derived from patients suffering from MS and from healthy controls.

Reference

  1. Panagiotis Douvaras, Jing Wang, Matthew Zimmer, Stephanie Hanchuk, Melanie A O'Bara, Saud Sadiq, Fraser J Sim, James Goldman, Valentina Fossati Efficient generation of myelinating oligodendrocytes from primary progressive multiple sclerosis patients by induced pluripotent stem cells. Stem Cell Reports: 2014, 3(2);250-9 PubMed 25254339

--Mark Hill (4/5)