Talk:2010 Group Project 3

From Embryology
Revision as of 15:42, 26 August 2010 by Z3292208 (talk | contribs)
Co-ordinator Comments
--This is an area for members of the group to communicate online and to place links and information relevant to the project. Do not forget to sign your additions and always add the newer material to the top of this page.

Projects: 1 | 2 | 3 | 4 | 5 | 6 | Students Page | Help:Editing Basics



--z3292208 03:57, 26 August 2010 (UTC)

Hey Mark I put on the page a picture of trisomy 21, Down sydrome, to slot in the disorders section.


--z3292208 11:10, 25 August 2010 (UTC)

Picture of the procedure:

http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mga&part=A1760&rendertype=figure&id=A1761

http://adam.about.com/encyclopedia/Amniocentesis_1.htm

Picture to put in from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2532964/


--User:Z3129413 08:15, 25 August 2010 (UTC)

Thanks 325.


--z3254753 07:45, 25 August 2010 (UTC)

yea bro, il bring my camera tomo.


--Z3129413 06:06, 25 August 2010 (UTC)z3129413 The page layout is awesome... Anyone have a digi camera at the moment can you bring it thurs/fri.. can get some snapshots for the page... return camera next lab if feasible...

--Mark Hill 04:39, 23 August 2010 (UTC) Ok you guys have been doing some talk here. Now is the time to start thinking how to populate your project page subheadings. Remember that anything you do can always be undone or altered at a later date. I also see an absence here of good visual material for your project.


--z3292208 02:01, 19 August 2010 (UTC)

History

Key scientists:

  • Douglas Bevis
  • Murray Barr and Ewart Bartram
    • 1949 were the first to study if the sex of a fetus can be found using amniocentesis anaylsis, and with that the possibility of sex linked diseases like hemophilia (a disorder of blood clotting).
    • The way the sex could be found = female cells have a cellular body attached, called the Barr body or sex chromatin, and male cells don't. This extra body, the sex chromatin, can be seen under the microscope.
    • Until amniocentesis in the 1950's, the only diagnostic technique used to warn women of having a child with a sex linked disease would be statistics based on family history, which was nothing more than loose probability.
    • Therefore is the sex of the baby could be found out pre-birth (along with the genomes of the mother and father of certain disorders), more reliable statistics could be calculated as to whether their baby might have a sex linked disorder.
    • http://www.ohiostatepress.org/books/Complete%20PDFs/Rothenberg%20Women/05.pdf
  • Dr. Carlo Valenti = 1968 first to use amniocentesis to diagnose a chromosomal/inherited disorder.
  • 1980's ultrasound techniques took out the guess work to guiding the needle during the procedure.


Procedure

Who is eligible for the test?

  • Since the procedure is invasive and therefore not without a number of risks, numerous tests are taken before to decide whether the mother is in the top category of women with a high chance of having a child with chromosomal or neural tube defect disorders.
  • These pre tests include:
    • Checking for abnormal ultrasound features
    • Maternal age is considered (>35 high risk of chromosomal disorders)
    • History of chromosomal disorders in the family, Rh +ve/-ve of the parents.
    • History of previous children born with a genetic defect.

When can the test be taken?

  • Most commonly during 15-16 weeks of gestation (during the second trimester), but can be done between weeks 14-20.
  • Second trimester amniocentesis is between weeks 15-18 (commonly wk 15-16).
  • Early amniocentesis is in the first trimester between weeks 11-14.
    • Has shown to have a rate of 3 times the rate of miscarriage.
    • Early amniocentesis has been conducted since the delay in the tissue analysis of an average of 2 weeks means if abortion is the option taken it is physically harder for the mother at a later stage of pregnancy, and emotionally as well.
    • The more common time is during second trimester since there is less risk of miscarriage and complications, and if an early diagnostic test is requested, CVS is a more recommended option.
  • Tissue culture takes a further 2-3 weeks before a result can be found.

Steps of the procedure

  • Counseling for the mother = review of genetic family history and history of any birth defects in previous children of the mother. Mother is also informed of the risks associated with the procedure, and is able to make a decision to continue based on weighing up the risks with her personal calculated chance of having a fetal abnormality.
  • Area is cleaned before needle insertion with an iodine solution.
  • Local anesthetic may be used but since there is little pain it usually isn't used to avoid having a second needle insertion.
  • Needle inserted and 15ml fluid taken, takes approx 30 seconds to withdraw the fluid.
  • Before the needle is inserted and whilst the needle is inside the uterus ultrasound is used to avoid harm to the baby and placenta.
  • After fluid is taken the baby's heart beat is checked to ensure there was no harm.
  • Fluid is cultured, the chromosomes are mapped = called karyotyping.
  • http://www.nevdgp.org.au/info/melb_us/Amniocentesis_melb.htm
  • http://www.plus-size-pregnancy.org/Prenatal%20Testing/prenataltest-amnios.htm


Note:

  • For diagnostic accuracy, comparing this technique to other techniques, I read that Chorionic Villi Sampling (CVS) can be used earlier on in the pregnancy, but the disadvantage of that is there is a greater risk of miscarriage. So there is a pro and con for amniocentesis against CVS.
    • Also i just thought to include in diagnostic accuracy, what about the occurrence of false positive results?? Are there any statistics relating to false positive cases, if there have been cases what were the outcomes, has there been any incidence of abortion as a result of a false positive for a disorder? (That could be an ethical issue too, are women more wary of the procedure in case it isnt 100% reliable and there is a chance of false positives?).
    • Have a look at this site too for diagnostic accuracy, there's a whole section which looks really useful, it says that even if the results of the test are 'normal' doesn't guarantee a normal baby, it also explains how some chromosomal tests can be ambiguous and an unsure diagnosis can result leaving mothers with uncertainty. http://www.plus-size-pregnancy.org/Prenatal%20Testing/prenataltest-amnios.htm
  • For risks, Evidence supporting the 1% risk of miscarriage statistic in the article http://www.ncbi.nlm.nih.gov/pubmed/18923654



--z3254753 23:17, 18 August 2010 (UTC)

Another point on ethical issues is the ethical decisions to be made if a problem is found. Is it ethical to terminate a pregnancy if it is found the child will have mental retardation? What factors are involved when making these choices? I don't think there is a right answer for everybody, so maybe its important in this section to present ethical arguements for all sides.

So yea, I think you've covered all the ethical issues, nice work!

Mark

--z3292208 23:06, 18 August 2010 (UTC)

For ethical issues i was thinking more along the lines of is the test too invasive for the mother? Not necessarily the risks (thats being covered separately) but would many women be unsure about the procedure because it is invasive and possibly painful, do people believe there are other techniques that could be as effective and more attractive to women. In this we could also do a brief comparison between amniocentesis and other diagnostic techniques, the positives and negatives of the procedure against others.

Also another ethical issue would be the choices the mother would make if a positive test of a disorder was found.

Tegan.


22:54 August 18 Z3129413: Yes tasks outlines are good. Diagnostic accuracy according to NATA guidelines can be accessed quite easily. NATA is the testing accrediting agency in Australia, which monitors pathology labortory testing accuracy in accordance to intesively reviewed set guidlines. Any lab operating wants to have NATA accreditation in order to display the logo on request forms etc. I think that all hospitals outsource genetic and pathology testing to semi or fully private companies which can also be part of the government health service. Those labs that are aligned with hospitals, usualy those located on the hospital campus itself, are all absolutely operating in accordance with NATA guidlines. The further question here is what are the inherant diagnostic inaccuracies associated with amniocentesis itself, if any? I dont know at this stage. Another question is , can amniocentesis be conducted in private rooms by a clinic, GP or other? Therefore are patients attending here protected by some sort of accreditation monitoring agency? I think leaving the diagnostic accuracy to involve only Australia is relavant, as it can be safe to assume that in places where medical proceedures are commonly understood to not generally fall below a certain standard, what happens in Australia applies to them also as the medical information and research is shared between these locations via published research studies from various universities etc. and are used by the various national accrediting agencies as reference material in formatting the guidlines. I will look into accessing the current plus or minus degrees of error and reference ranges used to diagnose the top most test requested for.

In tackling the last two topics,

A). Ethical issues and current research perhaps can tie in together (an option) - as at a glance I do not think there is much controversy surrounding the test per se, other than in terms of potential physical trauma to mother or infant due to accident at time of proceedure or malpractice, possibly instrument sterility issues re bacteria introduced into womb or abdominal wall. In light of the risks associated ( therefore proceedural ethics) in this regards,I will have to weigh it up with investigating if there are simple blood tests that can accurately diagnose the same tests requested from an amniocentesis. But this will be covered by 3. RISKS.

Alternate proceedures for the tests could be covered by 'Diagnostic accuracy' I will have to look into this. Maybe other proceedures (blood tests) are more accurate for some tests. so lets call that safety/ accuracy concerns. Maybe not to bring ethics into this at this point.

Propose '5.Diagnostic accuracy and efficiency'.

Propose '6.Outcomes from results' Of course there is the issue of receiving a positive test result. I can cover this as the 'medical outcomes' of the tests (what it allows the parents to do in light of the knowledge). Here is a major source of ethical debate.

Propose '7.Current research trends and ethical debates' State main streams of current research and the place they are being conducted, in order to highlight the fact that there may be differing laws govering research restrictions. give a brief outline of current laws (probably sourced from UN. I will aim to give specific examples of where public oppinion has opposed proposed research ideas. If it appears that personal related morality versus 'yes it is proceedurally ethical(safe to mother etc)' I will state that opinions differ in this regard. I will outline the purposes of the research and by then aiming to show any alternate methods of approaching the same research, if any, the ethical debate can then be structured in this way. For now I think this is the best way to approach this.

ie, research says yes switch to uranium to alleviate the use of coal,

- immediately build heaps of controversial (public oppinion- wasteful)reactors

- or wait until all alternatives (public oppinion non controversial-cleaner) alternate methods have been investigated fully.

In this way, I wish to show that (eg 'public opinion') has a reasonable (scientific) leg to stand on upto this point, and then if it is shown that there is no other viable option to obtain the required results from investigations, then it is purely a matter of ethics as to proceed or not or benefit from the knowledge gained by those that do, and that this perhaps is the debate as it stands in essence, as medical knowledge once gained by any means is definately going to be used by all in the long run. Thinking about this I might just paint the spectrum of oppinions and how they each believe they are doing the right thing in regards to a particular research topic.

example. (rough draft) 'in contrast to the controversy involved with the use of embryonic stem cells, research (reference information gained from Scientific American.com) has been conducted into stem cells gained from amniocentesis. Political,public and scientific (give examples) oppinion has supported amniotic fluid stemcells (AFS) because no embryo is used in obtaining these pluripotent cells (reference ScietificAmerican.com). The debate continues because researchers believe that AFS can be just as effective (will outline reasons) for research as those obtained from Embryos(ref, ScientificAmerican.com). Dr.(refs) sees this as a positive however Dr.(refs) states that there is no doing without embryonic stemcells because, but it can be seen that AFS research has much to offer according to institute ... (refs)"AFS can provide all etc etc. without the need to clone embryos(refs)". Religious and philosophical groups such as. support AFS for this reason.(refs)

this is an example of how I would structure the arguement..

hope this is all on track. see you in the lab

will post links shortly.


--z3292208 23:45, 15 August 2010 (UTC)

okay so I'll do 1 & 2, mark 3&4, 5,6,? if you think it's too much I don't mind picking up 5, let me know.

Tegan.


--Mark Woods 22:21, 15 August 2010 (UTC) yea, i can do 3 and 4 thats a good split :)

Mark

--z3292208 22:11, 15 August 2010 (UTC)


Im happy to do the first 2? 5 and 6 arent too big so maybe someone can do the last 3? and then someone do 3 and 4 (Mark if you wanted to do that?). Do you think thats a fair split?

Tegan.


--z3254753 13:08, 15 August 2010 (UTC)

hey guys, nice work with the refernces, I think those sub catagories work well. I've been looking for references, Im not sure how to link it but I was on pubmed n found something that could work for current research, its actually an alternative to amniocentesis. I figured we could use it to compare the two, and discuss why they're looking into an alternative.

[and emerging techniques of fetal cell separation from maternal blood]

As for dividing up tasks, we should do that asap. I wouldn't mind getting to sink my teeth into what genetic orders can be detected, and I'm up for any other.

statistics-

[on population-based prenatal screening and diagnosis of Down's syndrome]

[between serum biochemical markers and early amniocentesis in diagnosis of congenital fetal anomalies.]

accuracy - [| Accuracy of real-time polymerase chain reaction for Toxoplasma gondii in amniotic fluid. ].

ethics -

[considerations].


Mark

--z3292208 06:27, 15 August 2010 (UTC)

Here are some links to start off:

Historic background: http://www.ob-ultrasound.net/amniocentesis.html

Procedure: http://www.mjbovo.com/Pregnancy/PregAmnio.htm

Risks: http://www.wisegeek.com/what-are-the-risks-of-amniocentesis.htm

Main risks include 1) Miscarriage or pre-term labor, statistics have reduced in recent years. 2) Infection through the needle to the mother. 3) If the placenta is accidentally pricked mixing of neonatal blood and mothers blood may occur causing a condition where the mothers immune system attacks the fetus as a foreign body. This occurs due to a difference in blood type, one being Rh-positive, one being Rh-negative, although this can be tested before the procedure (checking the parents genotype) and extra care can be taken. 4) Harm to the baby from the needle, but ultrasound reduces this significantly.

Risk of miscarriage is less than 1% according to http://www.genetics.com.au/pdf/factsheets/fs17c.pdf.

Disorders detected: Amniocentesis takes a sample of the amniotic fluid containing fetal skin cells, from these they can look at the baby's chromosomes and detect any chromosomal disorders such as Down syndrome, trisomy 13 and trisomy 18. The sample taken can be tested for neural tube defects by looking at the amount of the protein alpha-fetoprotein (AFP), e.g. spina bifida and anencephaly (disorder where the top end of the neural tube fails to close during week 3-4 of development leading to portions of the brain and skull not being formed, usually leading to death before birth or very soon after). http://downsyndrome.about.com/od/diagnosingdownsyndrome/a/Amnio_ro.htm http://www.anencephaly.net/anencephaly.html


--z3292208 08:46, 12 August 2010 (UTC)

Hey guys so I've rethought the structure a bit and added some detail that we should look into:


1. Historic background:

- When was it first used?

- How was the technique developed?

- The key scientists involved.

- Trends in its use.


2. Procedure

- Who is eligible for the procedure?

- Are there women/couples more suited to the test? (e.g family history in genetic disorders or previous birth with a genetic defect)

- When is the test taken during pregnancy?

- How is the procedure performed? Method, steps involved.


3. Risks

- Side effects, complications, short and long term (short term like infections, long term possible effects to the baby, abortion or induced early birth?)

- Could do an advantages/disadvantages table maybe?

4. Disorders detected

- What components of the amniotic fluid do they isolate and analyse, and what do they test for? (I read that there are a few hundred disorders that they can test for but the parents and doctor only choose certain ones for them to test, and also there are some main ones so maybe we'll just pick the most common ones and do those, e.g. chromosomal disorders like Down syndrome and neural tube defects like spina bifida).

5. Diagnostic accuracy

- How accurate is the testing, statistics.

6. Ethical issues

- Professional and public opinions about the test, is it a more common diagnostic technique?

7. Current research

- Is there any current research being done to improve the procedure? There may not be...


What do you guys think? If there's anything you think we should add post it up top (apparently we're supposed to post new things at the top of the page) if not then we should think how to split up the workload so we can start getting into it.

Tegan.


--z3292208 00:14, 12 August 2010 (UTC)

Areas to look into:

1. Historic Background

2. Procedure, method.

3. Complications

4. Benefits, what disorders can be detected and prevented, option of abortion.

5. Current research on the procedure

Anything else you guys can think of to include?

--z3254753 00:33, 12 August 2010 (UTC)

nice work! i think '4.Benefits, what disorders can be detected and prevented, option of abortion' would be a big one, maybe whoever takes that one just has that point, and the other two ppl take two points each? what do you guys think?

hi everybody!


--Mark Hill 22:56, 11 August 2010 (UTC) Well group 3 where is your work that should have been done before this week's Lab?