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Revision as of 10:30, 17 October 2012 by Z3330986 (talk | contribs) (Lab Attendance)

Lab Attendance

Lab 1 --Z3330986 11:49, 25 July 2012 (EST)

Lab 2 --Z3330986 10:25, 1 August 2012 (EST)

Lab 3 --Z3330986 10:33, 8 August 2012 (EST)

Lab 4 --Z3330986 10:21, 15 August 2012 (EST)

Lab 5 --Z3330986 10:27, 22 August 2012 (EST)

Lab 6 --Z3330986 11:55, 29 August 2012 (EST)

Lab 7 --Z3330986 10:54, 12 September 2012 (EST)

Lab 8 --Z3330986 10:31, 19 September 2012 (EST)

Lab 9 --Z3330986 10:10, 26 September 2012 (EST)

Lab 11 --Z3330986 10:10, 10 October 2012 (EST)

Lab 12 --Z3330986 10:24, 17 October 2012 (EST)

Individual Assessment

Lab 1

1) As with many medical terms, in vitro is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to in vivo, inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[1]]

2) Sperm counts and sperm sex ratio in male infertility patients[[2]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

Lab 2

Mouse oocytes in vitro

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

Reference

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2 Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

Lab 3

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

Histology

  • Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:
  • Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for slow twitch contractile movements.
  • White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers
  • Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.
  • Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.
  • Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.
  • Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.

Lab 4

There are two main types of invasive prenatal diagnostic techniques

  • Amniocentesis - Amniotic fluid is taken and analysed between 14th and 18th week of pregnancy. It is used primarily to test for chromosomal defects such as Down Syndrome or fetal infections. It may be used to test for maternal hypertension (preeclampsia) by looking for protein biomarkers.
  • Chorionic villi sampling - Cells from the chorionic villus are taken between 10th and 12th week gestational age. It is used to test for chromosomal abnormalities such as Down syndrome or cystic fibrosis.

2) Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury

Traditionally when liver hepatocytes are damaged during end-stage liver disease, the only option has been transplantation. New research conducted by Burra et al (2011) however has focused upon using human umbilical cord mesenchymal stem cells (UCMSCs) as a form of regenerative treatment. In this study, UCMSCs were induced to form hepatic cell types through the use of growth factors in vitro, whilst ECM components derived from surgical specimens were used as a basis of support for these cells. These cells were then transplanted into carbon tetrachloride infected mouse livers which had undergone more than 40% necrosis of its total parenchymal tissue.

When UCMSCs were recruited within liver tissue, it was found that inflammation had been reduced through the regulation of pro-inflammatory cytokines and reduction of infiltrate. Furthermore there was a higher proportion of Kupffer cells (liver macrophages) identified through histological analysis compared to untreated liver tissue. This finding lends weight to the idea that UCMSCs accelerate liver cell recovery by attenuating the inflammation process.

Another therapeutic advantage of UCMSCs was the increase of catalase activity. The amount of catalase enzyme present in UCMSC treated liver tissue was markedly increased around Day 5, resulting in enhanced elimination of reactive oxygen species (ROS) which would otherwise cause oxidative damage to hepatocytes.

Lab 7

1a) A satellite cell, also referred to as a muscle stem cell, is a quiescent cell which functions to repair and or form new muscle fibres.

b) Activation of satellite cells occurs primarily during muscle injury. When a muscle fibre is damaged through physical injury, the satellite cells become mytotically active and fuse with the existing muscle fibres to repair the damaged tissue. Similarly in chronic diseases such as Duchenne’s muscular dystrophy, satellite cells are activated and differentiate into new myotubes in order to replace dying muscle fibres.

2) Damage to the motor nerve, classified as a motor neuron lesion, manifests in flaccid paralysis in the affected individual. This is a result of the loss of electrical signalling from the motor nuclei of the spinal cord to the muscle spindle. Consequently the individual presents with reduced muscle tone (hypotonia) and muscle wasting (atrophy). On a cellular level, muscle fibre size decreases whilst there is a fibre type shift from type I to type II fibres. This represents a down regulation of the slow myosin heavy chain (MHC) isoform and up regulation of fast MHC isoforms. [1]


References

1. Scelsi, R (2001). Skeletal Muscle Pathology after Spinal Cord Injury: Our 20 YearExperience and Results on Skeletal Muscle Changes in Paraplegics,Related to Functional Rehabilitation. Basic Appl Myol 11 (2): 75-85,

Peer assessment

Vision

Use of historic images was good. This is a main point of difference between this project and the rest. They are however not very well integrated into the project page, they feel as if they have simply been pasted there for the sake of inclusion. Perhaps an explanation of their significance could be included as well as how these drawings have lead to more refined understandings of specific structures. The Research History section is also quite interesting although it is very brief and could be improved if it were presented in a more visually appealing manner such as in a colour table.


The development structure and function section is excellent. The text is easy to follow and the student drawn images demonstrate a clear understanding of the processes as well as giving the reader the opportunity to better visualise the different stages of development. Another image which could be included would perhaps be a histological picture (as opposed to a diagram) of the different cell layers of the retina ie. The photoreceptor layer, inner nuclear layer etc. The current research section needs further refinement. I see no reason to simply list some current research articles except for point of reference. What needs to be done is explain how current research has changed or challenged traditional views/concepts. A brief summary of each article listed in this section is also warranted.


All images and relevant ideas appear to be appropriately cited and referenced. Image formatting on the whole is quite good although I think those included in the introduction need to be altered as they skew the text, making the section look awkward and a bit difficult to read.

Somatosensory

The introduction is ok, there is an imbalance between text and pictures. Particularly there is a sentence which reads “The following picture shows the general organization of the somatosensory system” however there is no picture. Also in terms of sentence structure, there are four sentences in a row which begin with “the somatosensory system...” or “the system...” Try to alternate how different ideas are expressed as at the moment the paragraph reads as a disjunct of ideas.


As a whole the page’s visual appeal needs ameliorating. There is far too much text and only two pictures, one of which is very large and appears to be compensating for a lack of smaller relevant diagrams within the body of each section. Having said this, the neural development section was very well done. It was detailed without being verbose and showed it was well researched. The hand drawn diagram is excellent. The cell biology part was also very well written and well structured however again, it simply need some visuals to aid in some descriptions of molecular processes. There appears not to be a continuous referencing style on the page. The introduction has in-text referencing whilst the rest of the page contains endnotes. A minor problem which could be fixed easily, though quite important nonetheless.

Olfaction

The project page was exceptional, there is a fine combination of text and images and the images are well integrated with the presented information. I particularly like the inclusion of a hand drawn histological section embedded within the table of historical findings. Perhaps this could also be done in the next table about the developmental timeline. As it stands, this table, while detailed in its wording may be difficult to understand as there are no diagrams to show the differentiation in visual terms, from week to week.


The clinical features, anatomy, and pathohophysiology were excellent. There is not much more to say. All of the diagrams were properly cited with correct copyright information. The CT scan was also interesting to look at.


One aspect that hasn’t been touched on is future research. The current research section was very detailed and explained the significance of each new finding however as is the nature of research, there are always gaps left in our understanding or further questions that need to be resolved as a result of new information. A brief section on this would give the project more depth as it would show a level of critique rather than simply the presentation of fact.

Abnormal vision

From the outset the page presents as well structured, particularly the introduction which provides the reader with a clear understanding of the purpose and content of the page. The following content is detailed and well researched with equal emphasis place upon each section. It appears that the page was contributed to equally by each member.


The image comparing the fundus between albinism and a normal eye is too small. The formatting is easily fixed by including the pixel size in the image insert directory. To find out how to do this refer to the wiki reference card we were given, or online. One minor structuring problem comes from the “ocular manifestations” sections. When it says “Major ocular disorders can be split into two separate sections based on the way in which they originated,” please list the two separate classifications immediately in bullet form. i.e.

  • Genetic
  • Environmental


By the time the section about the environmental origins arises, I forgot what it was referring back to and thus I had to scroll back up to deduce it was the second part of the ocular manifestations heading. Apart from this there are no other major faults of the project. All images are cited and copyright information clearly recognisable.

Hearing

I liked the tone of the introduction, it was light hearted and enjoyable to read, especially the image of the dog in the beginning which I thought was great. It also instructed the reader about the content of the page, thereby having a good balance between being engaging and informative.


The development section is extremely detailed, which is good in terms of showing a breadth of research and understanding however this needs to be offset with a greater deal of visual information. The subsections detailing the middle and outer ear are in need of some images showing the pharyngeal arches and their morphological changes from week to week. It would also be nice to see either some hand drawn images or computer drawn diagrams included somewhere in the page just for some variation. Towards the end of the page in the Abnormal hearing and the technological sections it tends to become very text heavy and need some image content. For example a photo of a cochlear implant would be useful.


There is some variation in the referencing style in Technology section with references appearing at the end of the section. It would be better to incorporate these references into the text as endnotes as they appear in the other sections of the project. Furthermore some of the tables are incomplete and require the addition of images. The image column in the structural malformations of the ear is empty. I’m not sure if there was a formatting problem or otherwise, though this need to be rectified.


Overall the page is very well written with an appropriate style aimed at students of the same level or higher. The glossary is extensive as is the reference list, showing an obvious depth of research.