User:Z3333427

Lab attendance

Lab 1 --Z3333427 10:31, 25 July 2012 (EST)

Lab 2 --Z3333427 10:05, 1 August 2012 (EST)

Lab 3 --Z3333427 10:09, 8 August 2012 (EST)

Lab 4 --Z3333427 10:08, 15 August 2012 (EST)

Lab exercises

Lab 1

1) Identify the origin of In Vitro Fertilization and the 2010 nobel prize winner associated with this technique and add a correctly formatted link to the Nobel page.

Dating back to 1953, the first intact human fertilized egg was extracted by John Rock reported by the Australian Foxton School researchers to be only a transient biochemical pregnancy. The first pregnancy made possible by in vitro human fertilisation (IVF) was reported in 1973 by the Lancet from Monash University, however the pregnancy itself only lasted a small number of days. It was not until 1978 that the first child (Louise Brown) was born with the help of IVF. The process was carried out by Steptoe and Edward successfully the year before. IVF History

At the Nobel price ceremony in 2010, Robert Edwards, was awarded the price in Physiology or Medicine for his contribution in the field of human infertility and the development of IVF treatment. Nobelprize.org

2)Identify and add a PubMed reference link to a recent paper on fertilisation and describe its key findings (1-2 paragraphs).

<pubmed>22611166</pubmed>

Today's couples are delaying childbirth to later stages in life which in many cases translate into complications with childbirth. The aim of this study is to assess the extent in which factors related with IVF treatments contribute to anxiety levels and mental health a year after childbirth.

The couples included were either of singleton pregnancy (IVF treatment) and subfertile couples (naturally conceived). Parental trait anxiety (Dutch version of the Spielberger State-Trait Anxiety Inventory) and mental health (Dutch version of General Health Questionnaire) were assessed 1 year after childbirth.

A hundred and ninety-six couples participated, in which 93% were eligible. Trait anxiety and mental health were similar in both groups (IVF and naturally conceived). However, fathers who had naturally conceived children more often recorded mental health scores in the clinical range (21%) compared to the fathers who had undergone IVF (9%).

Females risk of having a trait anxiety or mental health score was lowered by having a greater number of IVF treatment cycles, whereas males risk had been lowered by being treated by IVF for a longer time period prior to pregnancy.

Therefore it was concluded that IVF treatment is not associated an increase in clinically relevant Spielberger State-Trait scores in parents 1 year after childbirth. This study also indicated that a higher number of IVF treatment cycles and an extended time to pregnancy were associated with better mental health.

Lab 2 Assessment

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Conjugate Sperm Pairs

Question 1:

Conjugate Sperm Pairs in American Opossums

(A) Paired and single sperm of the short-tailed opossum Monodelphis domestica.

(B) Pairs of conjugate sperm attached by the heads, the top pair starting to separate after capacitation.

(C) Pair of conjugate sperm separating.

(D) Electron microscopy of exquisite sperm head alignment in conjugate sperm pair (credit: Harry Moore). doi:10.1371/journal.pbio.0060130.g003

Citation: Pizzari T, Foster KR (2008) Sperm Sociality: Cooperation, Altruism, and Spite. PLoS Biol 6(5): e130. doi:10.1371/journal.pbio.0060130

Copyright: © 2008 Pizzari and Foster. 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.

Question 2:

L-selectin is a cell adhesion protein that is associated with the implantation process. The protein is found on lymphocytes and belongs to the selectin family of proteins and play an important part in lymphocyte-endothelial cell interactions. It has been discovered that the outer cell of the blastocyst express the protein L-selectin during the time the uterus becomes enriched with carbohydrates. L-selectin is known to briefly bind to carbohydrates and the sticking interaction between the two molecules allow the embryo's progress along the uterine wall to slow down.

A study on L-selectin discovered that during the time of implantation, the trophoblast which are found on the outer layer of the blastocyst are the molecules which expresses L-selectin. The expression of L-selecting by trophoblast occur just in time for the embryo to slow down and for pregnancy to take place.

<pubmed>22717627</pubmed>

Lab 3

question 1

The 'gestational age' is defined as approximately 14 days (2weeks) prior to fertilisation which is a measure of days dating back to the last menstrual cycle. This is clinically significant as the 'gestational age' is easier and more accurately determined before and after birth compared to the 'post fertilisation age' which measures the age since the fertilisation of the egg.

Although 'gestational age' is about 2 weeks greater than 'post fertilisation age' it is still more clinically significant as the exact date of fertilisation is difficult to determine.

Gestational and Post fertilisation age

question 2

3 types of tissues formed from myotomes include bone (sclerotome), dermis (dermatome), skeletal muscle (myotome).

Histological description of:

• Bone (sclerotome)

- Bone is a specialised form of dense connective tissue which gives the skeleton the necessary rigidity. There are two histologically different type of bones:

Trabecular bone (spongy bone) which form a network consisting of branches of bars and sheets of bone. The opposite ends of long bones (epipyses)consist of trabeculae bone. It aids in the distribution of the load across the bone. Compact bone does not contain any macroscopically visible spaces or hollows. Compact bone mainly form the shaft (diaphysis) of long bones, and surrounds the marrow cavity. Compact bone aids in providing rigidity.

• Dermis (dermatome)

-The dermis is a thick layer of connective tissue which is the underlying layer the epidermis is attached to. The deepest part of the dermis is lined by subcutaneous tissue without a clearly defined boundary. The dermis varies in thickness but is about 1-2 mm, and can be divided into two sublayers:

The papillary layer is made up of loose connective tissue, which has a great number of capillaries and tend to fill hollows at the boundary which it shares with the epidermis. The collagen fibres in the papillary layer appear finer relative to the reticular layer. The reticular layer is comparatively more dense and contains less cells than the papillary layer which it underlies.

• skeletal muscle (myotome)

Skeletal muscle develop from mesoderm which occurs by the fusion event of mononucleated myoblast and the formation of mutinucleated myotubes that begin to express proteins which form sarcomeres within myofibers. Skeletal muscle fibres occur in bundles, which make up the muscle. The muscle is then surrounded by the epimysium (connective tissue). The surrounding connective tissue is continuous with the muscle fascia.

of the somites

Lab 4

Chorionic villus sampling (CVS) is one of a number of invasive prenatal diagnostic techniques. The diagnosis involves acquiring a sample of the placenta, which is then used to obtain information for genetic abnormalities through testing in placental tissue. In order to collect a sample of the placenta which contain chorionic villi, a needle is inserted into the placental tissue. A large number of chromosomal abnormalities, including trisomy 13, trisomy 18, down syndrome and Turner syndrome can be detected by CVS. A great number of genetic disorders, such as cystic fibrosis, and sickle cell disease. CVS is only considered to be a safe diagnostic procedure before the 14th week of gestation, and is not used to look for all genetic disorders, but only the diseases which the embryo is at increased risk for based on parental genes. [1] <pubmed>22708335</pubmed>