User:Z3331264

From Embryology

Lab Attendance

Lab 1--Z3331264 11:49, 25 July 2012 (EST)

Lab 2--Z3331264 10:02, 1 August 2012 (EST)

Lab 3--Z3331264 10:02, 8 August 2012 (EST)

Lab 4--Z3331264 11:08, 15 August 2012 (EST)

Lab 5--Z3331264 10:33, 22 August 2012 (EST)

Lab 6--Z3331264 10:29, 29 August 2012 (EST)

Lab 7--Z3331264 10:12, 12 September 2012 (EST)

--Z3331264 10:45, 26 September 2012 (EST)

--Z3331264 10:08, 3 October 2012 (EST)

--Z3331264 11:07, 10 October 2012 (EST)

--Z3331264 10:13, 17 October 2012 (EST)


Lab attendance logged for 11 practicals. --Mark Hill 07:50, 18 October 2012 (EST)

Lab 1: Fertilisation

2010 Nobel Prize Winner in Physiology or Medicine

Robert G. Edwards, For the development of in vitro fertilisation

For more Information

Recent Article on Fertilisation

Adiponectin and its receptors modulate granulosa cell and cumulus cell functions, fertility, and early embryo development in the mouse and human.

The expression of Adiponectin in mouse and human follicle cells was studied. Additionally, the function of this hormone in regulating fertilisation and early embryo development was observed. Adiponectin has been demonstrated to be secreted by adipocytes as well as ovarian cells. Their role in modulating metabolic homeostasis in granulosa and cumulus oophorus cells has also been studied. This study took into consideration, the impact of changing metabolic homeostasis on not only granulosa but also cumulus cells and thus the quality of the oocyte, pre-fertilisation. Adiponectin was shown to function as a cytokine and the levels of its receptors ADIPOR1 and ADIPOR2 were shown to be statistically significantly related to fertility outcome.

Consequently, adiponectin can enhance the quality of the oocyte pre-fertilisation as well as positively impact on embryonic development. While the particular genes involved in the response to adiponectin require further study, the applications of these results are promising. The addition of adiponectin to the maturation media of oocytes in human infertility care may improve the developmental competence of mature oocytes and enhance the possibility of successful in vitro fertilisation.

Interestingly, women with Polycystic Ovary Syndrome have lower levels of adiponectin which in turn alter the metabolic, steridogenic and apoptiotic activities of these cells. Such impacts have been hypothesised to be correlated with the lack of fertility in this cohort. Consequently, adjustments of adiponectin levels in treatment of this syndrome is a promising future research area.

Article on PubMed

<pubmed>22633650</pubmed>


Mark Hill - Excellent answers 10/10

Lab 2:Embryo Development

Protein required for Fertilisation













Implantation

The transcription factor CCAAT enhancer-binding protein β (C/EBPβ) plays a major role during decidualisation of the uterine stromal cells. Silencing of this protein suppressed the expression of Lamc1 which encodes for laminin. This protein is secreted by decidual cells as a constituent of the extracellular matrix (ECM). The loss of laminin impaired the ECM architecture and stromal cell differentiation. As a result of the impaired formation of a basal lamina-like matrix, trophoblast outgrowth is reduced and the progression of embryo implantation is prevented.

<pubmed>21471197</pubmed>


Mark Hill - Excellent answers 10/10

Lab 3

Gestational Age vs. post-fertilisation Age

The post-fertilization age is the age since fertilization of the egg while gestational age is age since the first day of the mother's last menstrual cycle before fertilisation has occurred. Gestational age is approximately two weeks greater than post-fertilization age. Gestational age is used clinically because its start date can be clearly determined from the mothers account and so is more accurate. On the other hand, the moment of fertilization must be inferred by adding 14 days, a variable time frame.

Fishton, P.M (2011) Embryo Fetus Development Stages [Internet]. Available from: http://www.livestrong.com/article/92683-embryo-fetus-development-stages/ [Last accessed 13/8/2012]

Tissue derived from somites

Initially the paraxial mesoderm undergoes segmentation to form the sclerotome and dermomyotome. Subsequent differentiation of the sclerotome results in the development of the vertebrae and Intervertebral discs. Additionally, the dermomyotome divides into the dermatome, which contributes to the dermis of the skin throughout the trunk and the myotome which forms the epaxial(dorsal) and hypaxial(ventrolateral) skeletal muscles of the body wall.

Dermis

The dermis is the connective tissue that supports the epidermis and binds it to the hypodermis. It consists of two indistinct layers, the superficial papillary layer and deeper reticular layer. The thin papillary layer is composed of loose connective tissue with populations of fibroblasts, mast cells, macrophages and often leucocytes that have been extravasated. This layer interdigitates with the epidermis, the external layer of skin separated from the dermis by a basement membrane. The reticular layer is a thicker layer composed of irregular dense connective tissue. In comparison with the papillary layer it has more fibers and fewer cells. The presence of elastic fibres allows for the elasticity of the skin. A rich supply of sympathetic effector nerves, hair follicles and gland structures are derived from the dermis.

Vertebrae

The vertebral column consists of a series of small bones. Each vertebra is lined by a thin outer layer of periosteum, a vascular fibrous layer surrounding bone, except over articular surfaces. It has an outer layer of collagen with elastic fibers. It provides vascular and nerve supply to bone. The medullary cavity of bone is lined with endosteum, a thin CT of osteoprogenitor cells and osteoblasts. The cortical region of vertbrae is composed of compact lamella. The unit of compact bone is the osteon, which are concentric layers of mineralised matrix surrounding a central vertical blood vessel and nerve carrying canal. This canal is lined by endosteum. Each osteon also has concentrically arranged osteocytes with radiating canaliculi allowing for communication with other osteocytes.Volkman's canals are horizontal canals which allow a connection between osteons. Spongy bone is an interconnected network of trabecular and many intertrabecular spaces which fill up the medullary cavity. The laminated structure is due to the arrangement of the collagen fibres within the trabeculae giving the bone its strength. The trabecular spaces are filled with bone marrow and is the site of hematopoiesis.

Muscle

Skeletal muscle consists of long, cylindrical multinucleated cells, forming muscle fibers. The oval nuclei are located at the periphery of the cell, just under the membrane. These multinucleated fibers create the endomysium, a delicate connective tissue to surround the fiber in conjunction with fibroblasts and reticular fibers. These individual fibers form fascicles that are surrounded by the perimysium, a thin septa of dense connective tissue extending inwards from the epimysium, which surrounds the collection of fascicles that make up the skeletal muscle. Blood vessels form a rich capillary network in the endomysium, while larger blood vessels and lymphatic vessels are found in the other layers. The epimysium is known to taper off and show continuity with the tendons. Motor nerves branch out within the perimysium connective tissue to give rise to several terminal nerves which may innervate a single muscle fibre or multiple at once (motor unit).

Mescher, L.A. (2010) Junqueira's Basic Histology. McGraw Hill, Singapore. Chapters 5,7,8.

Mark Hill - Good answers to both question. I find it interesting that your answer was from a Histology textbook and not an embryology text and appears asa direct quotation rather than your own work 8/10


Lab 4

Invasive Prenatal Diagnostics

Amniocentesis

This procedure is performed at a gestational age between 15 and 18 weeks. The amniotic fluid is sampled by inserting a needle through the mother's anterior abdominal and uterine walls to pierce the chorion and amnion. Approximately 15 to 20ml can be safely withdrawn. Real time ultrasonography is used as guidance for the physician by outlining the position of the fetus and placenta. Fetal cells can be separated from the amniotic fluid and karyotyped in order to detect for genetic abnormalities such as Trisomy 21 (Down Syndrome). Additionally, analysis of the alpha-fetoprotein levels can indicate neural-tube defects such as anencephaly and spina bifida.

Chorionic Villus Sampling

This procedure is performed at a much earlier gestational age of 10 weeks compared to Amniocentesis although has a 1% higher risk of miscarriage. Biopsies of 5-20mg of trophoblastic tissue are obtained by either a transabdominal needle insertion or transcervically, by passing a polyethylene catheter through the cervix guided by real-time ultrasonography. Chorionic Villus sampling tests for genetic abnormalities such as Trisomy 21, and X-linked disorders as well as inborn errors of metabolism.

Moore, K. L., Persaud, T. V. N. & Torchia, M. G. (2013). The Developing Human (9th ed.). Philadelphia, PA: Elsevier Saunders.

Cord Stem Cells Therapy

A study was conducted on mesenchymal cells with stem cell potential from Wharton's Jelly of the umbilical cord(HUMSCs). In this study, HUMSCs were isolated and transformed into dopaminergic neurons in vitro. These neuron-like cells were able to express neurofilament, functional mRNAs responsible for the syntheses of subunits of receptors capable of generating an inward current in response to neurotransmitters such as glutamate, an abnormality seen in patients with Parkinson's disease. These dopaminergic neurons were then transplanted into the striatum of rats that were previously made parkinsonian by the unilateral striatal lesioning with a neurotoxin(6-hydroxydopamine HCl).

The success rate of transplantation was characterised by positive staining for tyrosine hydroxylase (TH), the rate-limiting catecholaminergic synthesising enzyme, and the release of dopamine into the culture medium. The success rate of the transplantation was 12.7% and of these, the therapeutic outcome was indicated by a partially corrected lesion-induced amphetamine-evoked rotation. Rats with unilateral lesions to the substantia nigra rotate in response to amphetamine, and other dopaminergic receptor agonists where the number of rotations is directly proportional to the degree of denervation. Therefore, the cohort with the highest rotations benefited the least from therapy. The transplantation of invitro-differentiated HUMSCs alleviated the lesion-induced amphetamine-evoked rotation in the Parkinsonian rats, demonstrating potential therapeutic values. Additonally, a four month follow up after transplantation identified the prolonged viability of the transplanted cells and thus have the potential to treat human parkinson's patients.

The study's findings may have a significant impact on the study of Parkinson's disease and potentially help to circumvent worrying ethical issues. However before human studies, the success rate of transplantation must be improved as well as observation of the effects and side-effects for transplantations beyond 1 year. Such effects include behavioral effects, secretion of transmitters, activation of microglia, release of cytokines (such as tumor necrosis factor-α and interleukin-1β), and possible development of brain tumor. Finally, the toxicity of the growth factor (SHH and FGF8) and medium used should be examined.

<pubmed>16099997</pubmed>

Mark Hill - Good answers 10/10

Lab 7

Myosatellite cells

Myosatellite cells are mononuclear quiescent progenitor cells found sandwiched between the sarcolemma and basal lamina of a myofibre that become activated durin mechanical strain to augment existing or form new muscle fibres. <pubmed>PMC1571137</pubmed>

Satellite cell activation

Two instances where satellite cells are activated include muscle mechanical strain during exercise and muscle damage. During intense exercise, the forces generated by activation combined with stretch mean that the sarcomeres may be pulled out to such a degree that there is no longer any overlap of the actin and myosin filaments, thus causing damage. Following damage, it is believed that initial and pulsar release of mechanosensitive growth factor(MGF), results in activation of satellite cells. Alternatively, at the injured site, recruitment of inflammatory cells results, and the subsequent release of cytokines as well as Fibroblast Growth Factor (FGF) have been shown to activate myosatellite cells. Once satellite cells are activated, the release of cyclins allows the cells to come out of the G0 phase of growth, increase mRNA expression and so protein synthesis. This allows for microfiber replacement, regeneration or hypertrophy.

<pubmed>PMC1571137</pubmed>

Effects of long term motor nerve damage on Skeletal Muscle

After long term damage to motor nerves that innervate skeletal muscle, such as spinal cord injury(SCI),changes in fiber type and fiber size have been reported. Studies have shown that a progressive decrease in fiber diameter is observed with the extent of atrophy being directly proportional with the age of the injury. Studies have also shown that change in muscle fiber type to fast fibers accompanies muscle atrophy following SCI. A study of the paretic soleus muscle of a SCI patient cohort, that normally is predominantly composed of slow type 1 fibres, showed a shift to type 2b fibres 7-10 months post SCI. These changes have been observed as commencing four months after initial injury when there is a reported decrease of mitochondria, and build up lipid vacuoles within the fibre.The loss of mitochondria has been attributed to the immobilised, disused and so atrophic muscle of patients. The impairment of the mitochondrial oxidative enzyme activities accompanies morphological changes and also explains the build up of lipid vacuoles, the common energy source for mitochondria. Changes in to fast fibres has also been used to explain the fatigability encountered during muscle rehab exercises.


Scelsi R,2001, 'Skeletal Muscle Pathology after Spinal Cord Injury' Basic Appl Myol, 11(2):75-85.

Mark Hill - Good answers 10/10

Peer Assessment

VISION:

Overall, the key points relating to Vision and it’s development are being addressed at this stage by the page. There are some interesting descriptions that are easy to follow. However, in it’s entirety, the descriptions has to be sieved through in order to extract specific information. For example, the functions of each structure has been included in the development of each structure. While this provides a nice way for information to flow, it can be better received if function was separated from development and put under a separate sub-heading before development.

The history section, being in it’s early stages is off to a good start including some important contributions that date back to ancient times, which I find amazing. However, I would suggest, placing this information in the form of a table because full sentences are not necessary to achieve an understanding. It would also be important to include the specific advancements achieved from each moment, with relation to the eye. For example, what contribution did Aristotle’s dissection of the embryo, make to our understanding of the eye and it’s development? Does the age of the embryo tell us something?

Heading suggestions for the history:

1.TIME/PERIOD

2. HISTORIAN/SCIENTIST

3. EVENT

4. CONTRIBUTION TO OUR UNDERSTANDING OF THE EYE.

Moreover, the inclusion of the historic images are unique to the other groups and hence will spark an interest in readers. In saying this, the use of descriptions and appropriate titles will aid the readers in appreciating them from a contextual point of view.

Additionally, the scattered placement of images on the page makes it difficult to follow certain sections and properly use the images to aid my understanding. I suggest revising the method used and possibly having clear distinctions between images belonging to different sections. I.e. Some run over two sections.

I like how each component of the eye’s development is described separately giving us time to appreciated each one individually. However, the timeline of development is also important and sometimes, two components are dependent on each other for growth and development. This maybe something to consider when editing this section, so that an understanding that the entire process of growth and development overlaps amongst structures. A video might suffice here in place of text. Also, the importance of genes in patterning is not clear.

Current research section needs to built upon, maybe with some simple descriptions of the types of research taking place, their potential applications and limitations as well as the use of images that might help explain the conclusions of the project. Finally, the glossary needs to be expanded upon but so far the definitions are nice and simple for anyone to understand.

Good luck!

SOMATOSENSORY:

Overall, the key points relating to the topic area are being addressed. The use of current research to develop ideas and provide detail to the separate sub-headings is helpful. However, I would suggest better collaboration amongst team members about what is going to be addressed under each sub-heading because some repetition has taken place, particularly between touch and pressure where overlaps are expected occur. Additionally, there is clear imbalance between text and images and there are some areas where dot points, tables, images or videos will be better received by the audience than paragraphs of information.

More specifically, the history of discoveries can be tabulated and should include more historic events that may have taken place before Weber and possibly led to his research. In the section on pain, the bulk of the information can look more easy to read if the different fibres are bolded and put on separate lines with their accompanied descriptions or images or videos are used to replace the text.

A diagram or flow chart may be used in the hot/cold section accompanying or replacing the description on the sensation of temperature.

The section on pressure has all information cramped up in one paragraph which presents different ideas. I suggest each idea being put under a different heading or paragraph. For example, a paragraph on development, one on different structures and their functions (if needed since already addressed), one on research and applications. Images could be helpful!

So far current research looks promising and with the inclusions of more projects, would be interesting. I would suggest only including images in the research section when they can be simply understood and impact on the reader’s understanding or interpretation of the project.

The student diagram used in describing the somatosensory pathway is well done and makes a big difference to the page. The layout of this section is also organised and easy to follow and comprehend.

The references, although extremely extensive, is inconsistent between sections and a consensus should be met amongst team members, additionally, the glossary needs to be built upon. The inclusions of more definitions may help in limiting the text in each section.

Overall, there is no critique on the information presented on the page, it is all very interesting and current, however, a change in organisation of information will help bring this to the attention of the reader. Good luck!

TASTE:

The layout and balance between text and figures, tables, and diagrams is extremely well accomplished. All the information of the page is really intriguing and easy to follow on the majority. I would suggest placing the history of discoveries immediately after the introduction so that readers may appreciate all the research that would have had to take place in order to put all the information on this page. As well, this would help in having a separation between the two tables used.

When it comes to images, make sure that everything in the image is relevant to the accompanying text and important to the reader. One image where you might fall short of this criteria, is the very first image on the page about the five basic tastes, the names of the protein structures is more distracting and confusing than enlightening and overall would not aid in informing the reader.

I believe the introduction is very important in assisting the reader in gaining an overall understanding of the page and it’s aims. Hence I believe it is important to include a more succinct introduction with such aims. In this case, the introduction to the gustatory system begins defining structures and functions which are better off used elsewhere. Instead try giving an overview of the system and maybe give the reader a reason to read on.

The images used in the abnormality section are scattered and make it hard for the reader to determine which image corresponds to which idea, I would suggest ensuring that each image is detrimental to aiding the reader’s thoughts. This was an extremely interesting section.

Current research is clear, concise and easy to follow with a pleasant arrangement of ideas, text, and images. It was interesting to read. Additionally, the references and glossary are extensive and well done. I would suggest having a link to the glossary from within the text.

Well done on your project, and good luck with the rest.

ABNORMAL VISION:

As shown by your choice of sub-headings and research, the key points of your area of research are being addressed well! Your introduction flows well and gives a great overview of your page to the readers. Due to the focus of your page being on abnormal vision, a more succinct effort should be made to introducing normal eye development. I suggest the use of a student made flow diagram in order to clearly present the information as well as satisfy the criteria of this task.

The approach to the abnormalities section is so far on a great track. I particularly like the separation between genetic and environmental abnormalities as well as the use of a lot of research to introduce interesting concepts and clarify the reader’s understanding. In saying this, it would be beneficial to organise images in this section in a consistent manner, to mimic the image ‘appearance of cornea due to CHED’.

Be sure not to include too much detail on the molecular pathways and proteins if not entirely necessary in informing the audience about the abnormality in development. This would help eliminate any concepts that are too complex to understand.

The placement of the timeline before the new research was a good idea as it gives the reader good background knowledge. I would consider condensing this into a table so that it is more easy to read.

Overall, a great page but it could be more easier to read if the information was organised in a more succinct manner such as in tables, dot points and flow charts. The referencing style is consistent and correct and there is a good balance between old and current research.


HEARING:

What drew me into reading this page, was the humerous image at the beginning together with the perfect introduction that encourages people to read on. The sub-headings, headings, figures and tables make it really simple for the reader to take in all the key points of the research area. I particularly like the inclusion of technologies to detect abnormalities. However, this great balance is not met in the development section where there is too much text and not enough images or diagrams to guide the thinking. I would suggest trying to simplify the information into key points by eliminating any information that would not necessarily contribute to a sound understanding of the topic. This could possibly be achieved further by having a separation or different sub-heading for the description of the development process and the description of the cellular structure.

What stands out the most about this page, is the amount of research you have put in to the genetics and molecular processes of development and abnormalities. Whilst it is very interesting and shows the amount of time you've put into having a clear understanding, at times it seems the naming of genes and their proteins do not contribute to a sound understanding but rather adds confusion. For example, your reference to FGF and Sox are important but you have further included the different types of FGF and Sox proteins without offering much of an explanation about what distinguishes them from eachother. Generalising in these cases (to just FGF not FGF1,2,3..) would not limit the extent to which a student may learn from your information but will avoid any confusion.

Another way you could further improve the page is with the inclusion of student-drawn images or learning aids to accompany the text. This way you can avoid the inclusion of unnecessary information on borrowed images, for example, the wild-type inner ear morphology image. The referencing system is consistent and well set-out on the page and the long list of references and interesting discoveries is impressive. Overall I would just encourage condensing the information into dot points that help simplify the reader’s understanding.

Good luck!

Mark Hill - You have made a very good peer assessment of the group projects, in sufficient detail that provides useful information for other students. 10/10

Lab 9 Assessment

Current Research on Thyroid development

A recent paper discovered that an initially perceived kidney-specific adhesion molecule, expressed by CDH16, was found to also be expressed in the developing thyroid gland. In cell cultures, the cadherin protein has been found localised on the basolateral plasma membrane of the thyrocytes and is dependent on Thyroid Stimulating Hormone(TSH). Interestingly, this gene has been found to be enormously down-regulated in in papillary, follicular, and anaplastic thyroid carcinomas. This down-regulation results in an epithelial to mesenchymal transition of cancerous cells and so indicates in roles in development.

<pubmed>22028439</pubmed>

Embryonic layers and tissues that contribute to the developing teeth

The ectoderm, mesenchyme and neural crest ectomesenchyme all contribute to the development of the tooth. Additionally, local ectoderm thickening of the enamel epithelium signals the underlying mesenchyme of the odonotblasts to condense and differentiate.

<pubmed>12640730</pubmed>

Mark Hill - You have identified a protein OMIM CDH16 that is expressed in developing thyroid gland. You have also identified the germ cell layer contribution to teeth, perhaps you could have also identified what each formed within the tooth. 10/10

Lab 11 Assessment

A study by Koichi Oki et. al focused on examining the long-term changes after transplantation of human iPSC-derived cells in the stroke-damaged brain.[1] The use of embryonic or fetal stem cell-derived neural stem cells in treating Ischemic stroke in a rodent brain have been somewhat successful.[2] Studies have observed their differentation into neurons and the improvement of some impaired functions.[2] [3]These transplanted neural stem cells have also been shown to promote recovery even if differentiation into neurons does not occur. Such recovery is believed to be through the transplanted cells ability to modulate inflammation, stimulate angiogenesis and enhance brain plasticity.


Previous studies have also shown that autologous transplantation of neurons generated from iPSCs seems more favourable since they can differentaite into specific neuronal subtypes such as dopamingeric or motor neurons.[4] Recent studies have reported that implanted mouse iPSCs into the rodent brain generate large numbers of neuroblasts whereby a few differentiate but form tumours.[4] Human Fibroblast derived iPSCs implanted into the striatum of stroke-damaged rats improved short-term sensorimotor recovery. [5]


This current study transplanted long-term expandable neuro-epithelial-like stem cells (lt-NES) cells generated from adult human fibroblast-derived iPSCs, into stroke damaged mouse and rat brain[1]. It was shown that the iPSC-derived grafts survived long- term and contained a high proportion of cells with morphological and electrophysiological properties of neurons. These neurons received afferent inputs from the host brain and extended their axons to an appropriate target area. They were then able to send axonal projections throughout the host brain, receive synaptic input from surrounding host neurons, and improve motor recovery in behavioral tests relevant for human stroke.

References

  1. 1.0 1.1 <pubmed>22495829</pubmed>
  2. 2.0 2.1 <pubmed>20877642</pubmed>
  3. <pubmed>18286199</pubmed>
  4. 4.0 4.1 <pubmed> 20216552</pubmed> Cite error: Invalid <ref> tag; name "PMID20216552" defined multiple times with different content
  5. <pubmed>21465238</pubmed>

Mark Hill - Excellent 10/10