User:Z5030311
-- Welcome to the 2014 Embryology Course!
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- Note - Some guest assessments may require completion of a worksheet that will be handed in in class with your student name and ID.
Individual Lab Assessment |
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Lab 12 - Stem Cell Presentation Assessment | More Info | |
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Group | Comment | Mark (10) |
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7 |
2 |
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7.5 |
3 |
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7.5 |
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8.5 |
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8.5 |
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8.5 |
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7.5 |
Z5030311 (talk) 12:45, 6 August 2014 (EST)
Lab Attendance
Lab 1:--Z5030311 (talk) 12:53, 6 August 2014 (EST)
Lab 2:--Z5030311 (talk) 11:21, 13 August 2014 (EST)
Lab 3:--Z5030311 (talk) 11:07, 20 August 2014 (EST)
Lab 4:--Z5030311 (talk) 11:09, 27 August 2014 (EST)
Lab 5:--Z5030311 (talk) 11:12, 3 September 2014 (EST)
Lab 6:--Z5030311 (talk) 11:11, 10 September 2014 (EST)
Lab 7:--Z5030311 (talk) 11:14, 17 September 2014 (EST)
Lab 8:--Z5030311 (talk) 11:07, 24 September 2014 (EST)
Lab 9:--Z5030311 (talk) 11:24, 8 October 2014 (EST)
http://www.ncbi.nlm.nih.gov/pubmed PubMed
Lab 1 Assessment
http://www.ncbi.nlm.nih.gov/pubmed/25036713 <pubmed>25036713</pubmed>
Kisspeptin-54 is essential for human fertility as it is involved in the surge of luteinizing hormone and the maturation of oocytes. Studies have shown that a mutation inactivating the kisspeptin signal leads to infertility in women as there is no surge in the level of luteinizing hormone and so oocytes are not matured and released. In this study 53 women were injected with Kisspeptin-54 following superovulation; it was hoped that the Kisspeptin-54 would cause a surge in LH resulting in oocyte maturation. After 36 hours the oocytes were retrieved transvaginally, their maturation state was assessed and they were fertilized by intracytoplasmic sperm. Embryos were then formed from the fertilized oocyte. It was discovered that an injection of Kisspeptin-54 can increase the mean number of mature eggs produced by each patient and that it can induce oocyte maturation in patients with subfertility who are undergoing in vitro fertilization. In 92% of the patients who were given the Kisspeptin injection the oocyte was fertilized and the subsequent embryo was successfully implanted in the patient’s uterus.
http://www.ncbi.nlm.nih.gov/pubmed/24751928 <pubmed>24751928</pubmed>
One of the stages of IVF is superovulation, this is where multiple oocytes are stimulated to mature by injecting hormones into the patient. This study is proposing to adapt the levels of hormones used in superovulation for each patient so that the optimum number and size of oocytes is achieved. A mathematical model was constructed which predicted the dose of the hormones that would result in the optimum number and size of oocytes. The model was applied to real patients and the resulting oocytes were analyzed to see if the optimum oocytes were produced. The results showed that there were more oocytes and better sized oocytes when the levels of hormones were altered for each patient in comparison to the normal method where the hormone level is the same for each patient. This will improve the success of superovulation cycles and reduce the cost of excess medication.
Lab 2 Assessment
Lab 3 Assessment
Structures that arise from the Ureteric bud
<pubmed>25088264</pubmed> <pubmed>25087982</pubmed>
Structures that arise from the Metanephric mesoderm
<pubmed>18835385</pubmed> <pubmed>19726549</pubmed>
Lab 4 Assessment
1. <pubmed>24144029</pubmed>
An experimental study of preventing and treating acute radioactive enteritis with human umbilical cordmesenchymal stem cells
Human umbilical cord-derived stem mesenchymal cells were investigated on rats to see if they are able to cure radiation sickness in Humans. The rats used in this experiment had acute radioactive enteritis, which is where there is inflammation of the small intestine. The human stem cells used in the experiment were cultured in vitro and the rat models with the actue radioactive enteritis were established. The stems cells were then injected into the rats and the changes to the Visual and histopathological of the rats were observed.
It was found that rats that were treated with the human umbilical cord-derived stem mesenchymal cells had better survival rates compared to the control group. Histopathologically it was found that the treatment group also had more regenerative cells, stronger proliferation activity and there intestinal mucosa had a better structure.
2. The three developmental vascular "shunts" present in the embryo are Ductus arteriosus, Ductus venosus and Foramen ovale; all three close postnatally.
Ductus arteriosus is a blood vessel which connects the pulmonary artery and the proximal descending aorta; it allows blood to bypass the lungs.
Ductus venosus allows blood from the placenta to bypass the liver by shunting blood from the left umbilical vein to the inferior vena cava.
Foramen ovale is located in the heart and it allows blood to flow from the right atrium to the left atrium; this allows blood to bypass the lungs
Lab Assessment 5
Aganglionic colon (Hirschprung's disease)
Hirschprung’s disease is an absence of ganglia in the distal colon causing abnormal function of the gut. The disease is due to an abnormality during the development of the gastrointestinal tract; those individuals with the disease often do not pass meconium in the 24 hours that follow their delivery, patients will also show signs of dysmotility. The disease is diagnosed by histopathological examinations of colon biopsies.
Hirschprung’s disease is caused by the lack of complete migration by neural crest cells during embryonic development, these neural crest cells are precursors of enteric ganglion cells. The lack of enteric ganglion cells in portions of the distal colon result in sections of the colon unable to relax causing obstructions in the colon. As well as intestinal obstructions severe constipation can also occur due to the constant contraction of the gut.
Hirschhprung’s disease can affect different sized portions of the colon, in around 80% of patients only a small portion of the colon is affected and these cases can easily be cured with surgery. However in other patients much larger portions of the colon are affected which makes the cure for the disease harder and can result in death.
<pubmed>24168728</pubmed> <pubmed>25092084</pubmed>
Lab Assessment 7
<pubmed>24227653</pubmed> In this study the effect of the Insm1 gene on the differentiation of endocrine cells in the pituitary gland is investigated. The Insm1 gene encodes a zinc finger transcription factor which is found to be expressed in a variety of endocrine cell types. Mice with an Insm1 mutation were used in this study and it was found that if mice had a mutation in the Insm1 gene then they had an absence or reduced level of a variety of hormones including thyroid-stimulating hormone and growth hormone. The hormones with reduced levels are hormones that are characteristic of the different pituitary cell types. Therefore this study has shown that the Insm1 gene is involved in the differentiation of pituitary cells and that it is vital in embryonic development.
Neural crest-derived mesenchymal cells give rise to the dental papilla as they condense and then invade into the base of the tooth bud. Under the influence of the enamel epithelium the mesenchymal cells also give rise to odontoblasts; the odontoblasts secrete predentin which then calcifies to form dentin.
Another embryonic layer that gives rise to tissues in developing teeth is the ectoderm cells that are present in the oral epithelium, these cells differentiate to become ameloblasts which are cells on the surface of the developing tooth that produce enamel.
In teeth there is a specialised connective tissue that holds the tooth into the bony socket, this structure is called the periodontal ligament.
2. Initial thin ectodermal layer called the dental lamina which overlies the upper and lower jaw bones and this proliferates into two horse-shoe shaped structures which will become the future dental arcades. Enamel organs develop in the dental lamina in the form of rounded swellings and each swelling is the future site of a single tooth. The enamel organ partially encloses the adjacent mesodermal structure known as the dental papilla. Unenclosed mesoderm of the dental papilla surrounds urrounds this and forms a follicular sac. Tooth germ: Enamel organ, dental papilla and follicular sac. Respectively they form the enamel cap of the tooth crown, the dentine and pulp chamber of the tooth and the periodontal membrane.
Lab Assessment 8
There are several embryonic stages in testis development; these include the differentiation of the gonads into gender specific organs and the differentiation of the internal organs. The differentiation of the external organs and the development of secondary sexual characteristics occur during the foetal and postnatal periods.
In week 6 the genital ridge develops from intermediate mesoderm, this is also known as the undifferentiated gonad; in order for the gonad to differentiate into a specific sex organ signals from particular genes on the Y chromosome are released. The SRY gene, discovered in 1990, is a protein coding gene on the Y chromosome which is essential for the differentiation of the gonads into testes. SRY codes for a 204 amino acid protein; this protein initiates the differentiation of the gonad by binding to specific regions of DNA and expressing certain genes.
SRY causes the primordial of the supporting cells to develop into Sertoli cells, these cells control the further differentiation of the gonad by instructing the germ cells and other cells to go down the male route of development. The Sertoli cells surround the germ cells, form the testis cord and cause Leydig cells to differentiate; this occurs at around day 42. Sertoli cells also express anti-Mullerian hormone (AMH) which prevents female reproductive organs to form, the expression of AMH causes the paramesonephric (Mullerian) duct to degenerate. The Leydig cells produce testosterone and this controls mesonephric (Wolffian) duct differentiation; the rete testis form from the mesonephric tubules that grow towards the testis cords and ductus deferens form from the mesonephric duct extending out of the gonads. The testis cord and the germ cells differentiate into seminiferous tubules. At 49 days there is a clear difference between male and female gonads, after this point the internal organs continue to develop and external organs begin to form.
The image shows the positions of the Wolffian and Mullerian ducts in the undifferentiated gonad before the Mullerian duct is degenerated and the Wolffian duct is differentiated.