User:Z3332863

From Embryology

Lab Attendance

Lab 1 --Z3332863 11:47, 25 July 2012 (EST)

Lab 2 --Z3332863 10:20, 1 August 2012 (EST)

Lab 3 --Z3332863 10:05, 8 August 2012 (EST)

Lab 4 --Z3332863 10:18, 15 August 2012 (EST)

Lab 5 --Z3332863 10:01, 22 August 2012 (EST)

lab 6 --Z3332863 10:04, 29 August 2012 (EST)

Lab 7--Z3332863 09:59, 12 September 2012 (EST)

Lab 8 --Z3332863 10:10, 19 September 2012 (EST)

Individual Assessments and Practical work

Lab1

Assessment:


Origin of Nobel Prize & Discoverer

In 2010, Robert G. Edwards won the Nobel Prize for developing In vitro Fertilisation. IVF originated in 1950s when Edwards began fertilizing human eggs in cell culture dishes as a way of treating infertility. In 1978, Edward's IVF technology gave the world's first IVF baby. Over the next few years, Edwards and his team fine-tuned the technique of IVF.

[1]


Research paper on fertilisation:

<pubmed>22317970</pubmed>


What does this paper tell us about fertilisation?

This article looks at the rise of aneuploidies in IVF embryos from women around 40yrs of age. To do this Handyside et al, used 'microarray comparative genomic hybridisation' technology to study the chromosome copy number in the zygote, the 1st and 2nd polar bodies in older women receiving IVF treatment. Handyside et al found that:

  • Most of the aneuploidies of IVF embryos arose from the 2nd meiotic division of the oocyte. This is surprising because most aneuploidies in naturally fertilized embryos arise from Meiosis I of the oocyte.
  • Aneuploidies in IVF zygotes were not due to non-disjunction of chromosomes in the oocyte. Instead, these Aneuploidies were due to predivision of the chromatids in the oocyte.
  • In IVF zygotes made from aged oocytes, often there were multiple aneuploidies in 1 zygote.

By looking at the origin of aneuploidies in IVF zygotes, these scientists are trying to find a way to reduce these aneuploidies.


Lab 2 Prac work

Prac class work (not the assessment - see section after this for assessment

Genes that display significant strain by stage variation fall into four main categories

Genes that display strain variation.png

Genes that display significant strain by stage variation fall into four main categories. The genes that show significant variation due to strain by stage interaction were clustered hierarchically. Four distinct patterns appear in the clustered data, identified by the letters A–D. CB4856 (H) are on the left, from the egg to the young adult, while N2 (N) are on the right, from the egg to the young adult. Missing values were imputed using KNN-impute and expression values represent the average from four replicates.


Further Description

Capra et al were studying the variation in gene expression during the different stages of Development of different isolates of C. elegans. This image is a microarray result, showing genes that are expressed in different amounts in different strains of C. elegans during development. This Micrarray shows allow these differentially expressed genes to be classified into 4 groups. It’s likely the genes in the same cluster are regulated in the same way.


Reference <pubmed>19116648</pubmed>

Copyright 2008 Capra et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.



lab 2 Assessment

Q1. Paper & Image Related to Fertilization


Detection and Localisation of HPV in Sperms

Detection and Localisation of HPV in Sperms.png Detection and localization of HPV in human sperm.

a. Fluorescence in situ hybridization (fluorescence microscope) for HPV DNA on sperm from a patient with HPV16 in semen. Infected and noninfected sperm are shown. Red: HPV DNA (Texas red); blue: nuclear staining (DAPI). b. Immunofluorescence (confocal fluorescence microscope) for HPV16 capsid protein L1 on sperm from a control (left) and a patient with HPV16 in semen (right). Upper panel, L1 antibody; central panel, L1 antibody and Pisum Sativum (acrosome); lower panel, L1 antibody and Pisum Sativum after induction of the acrosome reaction. Red: HPV16 L1; green: Pisum Sativum; blue: nuclear staining (DAPI). c. PCR for HPV E7 gene from sperm DNA. Lane M: DNA marker (100 bp); 1: negative control (no template); 2: positive control (sperm transfected with recombinant plasmid pIRES2-AcGFP1-E6E7); 3: sperm from a patient with HPV16 in semen; 4: sperm from a control subject.


Outline of the Research:

The results of Foresta et al show that Human Papilloma Virus (HPV) can infect sperm through interactions between the virus’ capsid proteins and Syndecan-1 of the sperm. They also found these infected sperm can fertilize the egg and pass the virus into the oocyte


Reference:

<Pubmed>21408100</pubmed>


Copyright

2011 Carlo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Note - This image was originally uploaded as part of an undergraduate science student project and may contain inaccuracies in either description or acknowledgements. Students have been advised in writing concerning the reuse of content and may accidentally have misunderstood the original terms of use. If image reuse on this non-commercial educational site infringes your existing copyright, please contact the site editor for immediate removal.



'Q2. Protein Involved in Implantation'


Protein: WNT4

Franco et al discovered that WNT4 plays a crucial role inregulating uterine development, Progesterone signalling and decidualization during Embryo Implantation. They used a WNT4 deficient mouse model to show that without WNT4, there were:

  • Defects in Endometrial stromal cell survival
  • reduction in uterine glands
  • reduced responsiveness of endometrial cells to progesterone.

Franco et al used a mouse with fully functional Wnt4 as a control and these abnormalities were not seen in the Wnt4 expressing mouse. These researchers studied the Implantation sites of WNT4 deficient versus the control mice. They discovered, while all of the control mice showed implantation sites, only 25% of the WNT4 deficient mice had evidence of implantation. This means without WNT4, implantation cannot take place in most mice. The area of the implantation site in WNT4 deficient mice was smaller than control.

In WNT4 deficient mice, there was also a reduction in Decidualization. Franco et al induced an artificial decidualization in these mice and found the WNT4 deficient mice had a smaller decidual horn (uterine horn) than the control mice with functional WNT4. They found Wnt4 drives decidualization by enhancing the survival and differentiation of the stromal cells in the endometrium.

They noticed that in the WNT4 deficient mouse, another protein Foxa2 was reduced, in comparison to WNT4 expressing mouse. Foxa2 is expressed in uterine glands and is important in their development. Furthermore, leukemia inhibitory factor (Lif), a protein secreted by uterine glands, was also reduced in WNT4 deficient mice but not the control.


<pubmed>21163860</pubmed>


Lab 3 Assessment

Q1. Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development.

  • Gestational age is the age of the Conceptus or Pregnancy. Gestational age is timed from the first day of the woman's last Menstrual Cycle. However, Post-fertilisation age is the time lapsed since fertilisation of the oocyte.
  • Gestational age is used clinically because it is hard to pinpoint the exact day of Fertilisation. Ostetricians can ask the woman when was the first day of her last menstruation to work out the gestation age.

Reference:

[2]

Q2. Identify using histological descriptions at least 3 different types of tissues formed from somites.

  • Skeletal Muscle - Formed from the Myotome of the somites. Skeletal muscle is made up of contractile units called Sarcomeres. Components of sarcomeres can be seen using electron microscopes. The sarcomere has a Lightly coloured H band in the middle. This H band consists of actin filaments and myosin tails. The myosin heads interact with actin in the A band (just beside the H band). This gives the Dark band seen under the miscroscope. On the sides of each sarcomere is the Z disc where actin filaments of adjacent sarcomeres are attached.
  • Dermis - formed from the Dermatome of the somites. dermis is the deep layer of skin, under the epidermis. Dermis is divided into 2 layers - Papillary layer and Reticular layer. Papillary layer has very fine collagen fibres and lots of cells and blood vessels. It is made up of loose connective tissue. Reticular layer is a dense connective tissue layer, made up of bundles of interlacing collagen fibres.


  • Bone - Vertebral body and Intervertebral disc are formed from the Sclerotome of the Somites. Histologically, bone form 2 types of organisations - Compact bone and Trabecular bone. Vertebrae are made up of mainly trabecular bone. Trabecular bone is deposited in the form of lamellae but the lamellae do not form Haversian systems. Trabecular bone is made up of tiny bony bars with intervening spaces. A fully developed vertebral column is made up of 7 cervical, 12 thoracic, 5 lumbar, 5 (fused together) sacral and 1 coccygeal vertebrae. The Invertebral discs are made up of a gelatinous nucleus pulposus, enclosed in a fibrous annulus fibrosis. The annulus is made up of concentric rings of collagen fibres. These fibres fuse with the longitudinal ligaments. reference: <pubmed>16595436</pubmed>


Reference: Blue Histology [3]


Lab 4 Assessment

1. Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques.


Chorionic Villus Sampling (CVS)

Catheter is passed into the uterus to collect cells from the placental Chorionic Villi. Ultrasound is used to guide the catheter to the chorionic villi. CVS identifies the karyotype of fetus. CVS identifies chromosomal diseases like:

  • Down’s Syndrome
  • Tay-Sachs
  • Cystic Fibrosis
  • sickle cell anaemia

Reference: [4]

Cordocentesis:

Fetal blood is taken from the Umbilical vein, at the placental end of the vein. Ultrasound imaging is used to guide the needle to the umbilical vein. Blood cells are analyzed in the lab. Cordocentesis looks for the following abnormalities:

  • Infections like toxoplasmosis, Cytomeglovirus and rubella
  • fetal Anaemia
  • isoimmunisation
  • Down's Syndrome

Reference: [5]


2. Identify a paper that uses cord stem cells therapeutically and write a brief (2-3 paragraph) description of the paper's findings.

<pubmed>16223852</pubmed>

This paper investigates the therapeutic value of Umbilical Matrix Stem Cells (UMSC) which is found in Wharton’s Jelly of the umbilical cord. UMSC may be used to treat Parkinson’s disease. Rats with Parkinson’s disease (PD model rats) were given human UMSC as a transplant. One of their preliminary experiments showed there is no rejection of the transplanted cells. Severity of Parkinson’s disease in rats is measured by rotational behaviour of the rats – the more rotations, the worse the disease. Rats with UMSC implant showed a significant reduction in the number of rotations compared to those without UMSC transplant.

Weiss et al also found an increase in the number of Dopaminergic (DA) neurons in PD model rats that were given the UMSC transplant. Weiss et al found UMSC secrete large amounts of GDNF that can stimulate DA neuron growth and fibroblast growth factor 20 which can increase the survival of DA neurons. These factors secreted by UMSC may be responsible for the increased number of DA neurons seen in the rat’s brains after UMSC transplant. Low DA neurons, especially in the ventral tegmental area, are responsible for Parkinson’s disease. Thus by increasing the number of DA neurons UMSC may treat Parkinson’s disease in people.

Lab 7 Assessment

1. (a) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated ?

  • A muscle satellite cell is stem cell located in skeletal muscle that promotes regeneration, growth and repair of skeletal muscle fibers. [6]
  • Satellite cells can be activated after extreme exercise. A study was done by Darr et al where mice were vigorously exercised and the level of activated satellite cells were measured before and after their exercise. [1] This study showed exercise can increase the level of satellite cell proliferation which is needed to repair necrotic muscle fibers as a result of extreme exercise. [1] Exercising skeletal muscles may release mitogenic factors that increase satellite cell activation and proliferation. [1] Insulin-like Growth Factor I (IGF-1) can induce skeletal muscle hypertrophy. [2] This hypertrophy may be caused by activation satellite cells. [2] Activated satellite cells increases protein synthesis in muscle fibers to cause muscle hypertrophy. [2] Thus another example of satellite cell action is in IGF-1 induced muscle hypertrophy. [2] Satellite cells are aslo activated in Duchene's Muscular Dystrophy (DMD). [3] In DMD, fibres are lost due to a deficiency in Dystrophin which causes tearing in the cell membrane and activated satellite cells proliferate to replace these lost cells. [3] as the age of the DMD patients increase, the replicative potential of the satellite cells reduce, more so than the control (children without DMD). [3]


2. In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?

In mice, cutting the spinal cord results in severe atrophy of the muscle fibers. [4] This is where muscle fibers reduce their size and cross-sectional fiber area. [4] Muscle fibers also seem to switch to a 'fast' phenotype, instead of slow fibers. [4]Sustained motor neuron injury also increases the amount of Myosin Heavy chain 2b in skeletal muscle fibers. [4]


Reference:

[1] <pubmed>3693217</pubmed>

[2] <pubmed>10632630</pubmed>

[3] <pubmed>2267630</pubmed>

[4] <pubmed>9755066</pubmed>


Peer Assessment

Abnormal Vision

Pro:

  • Succinct normal function section. It gives enough background info so we can understand the abnormalities.
  • great images - increases people's interest in such disorders.

Con

  • Can you put in a glossary? What is Anterior Segment Dysgenesis? Is that just anterior segment of eye not forming at all?
  • With the setting out, it's probably better to have the following layout:
    • Gene Mutation
    • All diseases resulting from this mutation
    • details about the disease
  • It's just I thought you talk about Px6 and FOX in the beginning but it's not until the very end that we know about the diseases (anophthalmia and microphthalmia) that orginate from such mutation


Vision:

Great eye image at the start to capture attention. It's nice to see that it has the correct referencing and copyright.

The introduction is very clear and simple to read. Overall the written content is easy to understand and provides sufficient detail to cover the developmental stages of the eye and associated structures like the optic nerve and lacrimal glands.

The images throughout the project were very useful because they complement the text nicely. The student drawn diagrams made the optic vesicle formation easier to understand. However, I think the labels are a bit small - you can really only read them if you click on them and see the larger version. If you can put some labels on the orientation (such as the ventral side, posterior side, etc), that would be great too. Can you also put a reference as to where you got the information to draw these images from?

The images you got from the 'Atlas of development of man volume 2', can you put the copyright up? Not many textbooks allow using their images but if it is allowed for this book, you should definitely include the copyright there.

Sections that seemed incomplete are history and current research. with the current research information you uploaded, can you add a bit more text just to summarize what the study found out? There's a picture there with some description but it would be good if you can put into dot points what the significant findings are.

It would also be good if you can write something on the visual cortex of the brain. I think it links in with the section on Optic nerve. Maybe mention some of the genes related to the various stages of eye development. It doesn't have to be a lot of detail - just suggest what stage of development the genes are responsible for.

It would be good if you used more research papers instead of using the textbooks. If you are using the textbooks, it's good to track down the references the textbook used. This means you can put the relevant research papers as reference instead.

--Z3332863 16:09, 23 September 2012 (EST)


Taste Development

The introduction seemed to go into a lot of detail. for example, the information on Type II receptors should be placed in the same section as neural pathways, not the introduction. Can you also include in your introduction, an overview of what you are going to talk about in your project? That would give your project more structure.

With the neural pathway section, can you draw or find a diagram for that section? I find it hard to understand without one. The taste map section goes into a lot of detail which I think is unnecessary because this is a development project.

Current research section is very interesting. I don't think you need to add any more content on that section - that section to me looks complete, besides a few formatting and referencing issues with the images.

Overall, I felt there wasn't enough written on the development of taste, either the receptors (taste buds) or the neural pathways. Your project seem to focus on the anatomy and physiology or function of the taste system. This is alright to keep but the focus should be on development. You do have a Time-line of taste development that summarizes the development of the Gustatory system which is great to see. I think use that as a starting point and expand on each stage in text form, below the table. In week 12 development in this time-line, you mention 'epithelial types I and II', what are they? Are they similar to skin cells?

Overall, the balance between images and text is great. The colourful images work wonders in breaking up the text. Having said that, Many of your images did not have the correct PMID referencing. These images include:

  • images of taste being revoked by visualizing ATP release
  • CVP of WT and DKO mouse with H & E and SEM
  • histology - can you give a more relevant title for this image? We know it's histology; we can see that. What is this image about?
  • Abnormal of Tongue - it should say abnormality of tongue

The history section is excellent because it spans over such a long time - 350BC to 2010. The layout of a coloured table for history is beautiful, clear and concise.

--Z3332863 16:35, 23 September 2012 (EST)


Group Project notes and Articles

Article on Pain Development:

<pubmed>16446141</pubmed>