sfk
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hello everyone. just a quick question.
If loss of both tumour suppressor genes is reqd for disease expression, eg in retinoblastoma, how is it that it is considered to be autosomal dominant? coz as far as i can understand, autosomal dominant disorders can be expressed if only one gene abnormality is present.
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| dr ruman
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yeah thats true that for AD gene inheritance just one gene required ,butr its related to INHERITANCE,but as far gene EXPRESSION i.e signs and symptoms to appear ,2 hit theory is applied,that ok its AD disorder it means pt has gene in his chromosomes for sure but when it will express itself depends on different mechanism including 2 hit theory of both allele supression ,variable expression,penetrance etc
hope i explained ..........
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Living each day as a preparation for the next is an exciting way to live. Looking forward to something is much more fun than looking back at something—so lets do it together
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| hope4dabest
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Hey guys..whats happening???
Well i guess m the first one here in Nov to go for the torture...
M doing FA these days and my biggest problem is retaining things and trust me FA is doing its job pretty good..
Dont forget FA guys, i know some ppl say its pathetic but some even say that they could show theor 80% questions from it...M actually hoping this
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| sfk
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thanks dr ruman. what about mutations in oncogenes??? Sorry for bothering, but we all should be prepared if we have to face the beast in nov.
Good luck hope. when is the D-day?
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| simi
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hello everybody....hope everyone is studying hard in these last days
key: thanks a lot for the advice ...yes ...i also decided that i should not worry too much about 100 qs each day...u n me writing exam on same day
shohreh,cleopatra n fanaye...i understand coz i too study with a baby...he is 16 mths old...its tough but we have to be strong n keep moving....
no internet connection yesterday...so i decided to complete hemato ...still doing it....got the connection now...will start with qs once i finish the whole chapter....soooooo many lectures in hemato...i am left with 2  ...ok then have a productive day everybody
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| simi
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Topics: 53
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hello everybody....hope everyone is studying hard in these last days
key: thanks a lot for the advice ...yes ...i also decided that i should not worry too much about 100 qs each day...u n me writing exam on same day
shohreh,cleopatra n fanaye...i understand coz i too study with a baby...he is 16 mths old...its tough but we have to be strong n keep moving....
no internet connection yesterday...so i decided to complete hemato ...still doing it....got the connection now...will start with qs once i finish the whole chapter....soooooo many lectures in hemato...i am left with 2 ...ok then have a productive day everybody
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| mikky
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shoresh,cleopatra,fanaye n simi
i really appreciate the effort u r putting....
may god bless u nd giv u the strength 2 go ahead...
all the best...
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| fanaye
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how are you all what is your plan for saturday and sunday i mean study wise. Jst wanted to remind you in your revision you might have set a time to revise ct scans and pathology images from webpath please dont forget to see ventilation perfusion scans how to differentiate what you see on the chest scan is due to ventilation or perfusion deffect.
let it be a productive day for all of you
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| dr ruman
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thx fanaye,nice advise i want to add one more thing,yup keep revsing scans ,slides alongwith text of a system as it consolidates all concept and image,but dont forget to keep in ur schedu;e to revise all slides and scans closer to exam ,i mean 2 ,3 dyas before
sfk:hmm i didnt get ur question regarding oncogenes,well all mechanism depends again on mutations,translocations ,mismatch repairs,deletion ,inserttion,inframe,frameshift
but again autosomal dominant or recessive patterns determine presence or hidden state of disease ,or early or late expression of disease,AR will never express disease wether its oncogene involved or other mutation,he will just pass on to next generation and express it unless homozygous.so AD and AR modes of inheritance ,dont confuse them with mechanism of disease production by gene mutations,supression,overexpression etc
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Living each day as a preparation for the next is an exciting way to live. Looking forward to something is much more fun than looking back at something—so lets do it together
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| sfk
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Posts: 300
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fanaye nice advise. googled ventilation perfusion scans. still not clear about ventilation defects. i candiagnose PE, i think.
dr ruman: i got what u are saying. but i had read somewhere in kaplan that both tumour suppressor genes must be lost for disease expression, while abnormality in only one copy of oncogene causes disease. & then there was a mention of AD and AR which confused me. Actually i cant remember where exactly i read that.
BTW, folks does this happen to u as well. i have trouble recalling where i read a particular piece of info and if i need to read it again i have to look for it all over, and when i cant find it, it drives me crazy.
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| cleopatra
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Hello there people how is every1 doing today SFK i think that happens to most of us wont it have been worse if u remember where you read it but never sank in you head what you read so u r on the right path.
anyway as dr_ruman said the expalnation is the Two-Hit theory,single mutations in tumor suppressor genes occur in germ line and inactivates 1 allele of the crucial gene this mutation is passed on to the offspring of affected parent a 2nd mutation occurs in the somatic cell of offspring knocking out the other allele to give a homozygous state and a predisposition of cell to develope cancer.
i hope that helps.
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| shohreh
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hi simi ,cleopatra and fanaya
happy to hear there are some people like me
ATTENTION...
my friends can i asked about your scores in uw until now?and is this the first round?
mine is :
FIRST TIME :42%...21Th..NOT COMPLETED
what about you?
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| cleopatra
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my simple explanation as to why Retinoblastoma is considered AD is the 2nd mutation is the 1 being considered not the inherited 1coz other family members still have 1 defective allele but do not present with the disease unless 2nd 1 is also knocked out u see they do this to us to make our life difficult is all i think
happy reading to all
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| shohreh
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shohreh wrote:hi simi ,cleopatra and fanaya happy to hear there are some people like me ATTENTION... my friends can i asked about your scores in uw until now?and is this the first round? mine is : FIRST TIME :42%...21Th..NOT COMPLETED what about you?
please answer
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| sfk
Forum Elite
Topics: 47
Posts: 300
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cleopatra wrote:my simple explanation as to why Retinoblastoma is considered AD is the 2nd mutation is the 1 being considered not the inherited 1coz other family members still have 1 defective allele but do not present with the disease unless 2nd 1 is also knocked out u see they do this to us to make our life difficult is all i think happy reading to all
1 defective allele in other family members---> however no disease ---> and yet AD????
sorry if i'm making u all mad.
shohreh dont worry about scores as long as u understand why u went wrong. However ur scores SHOULD improve over time. Good luck.
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| cleopatra
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Hey sfk that explanation first of all does not apply to all AD it applies to the inherited form of Rb and secondly single 1st mutaion is in the germ line and thats why i said the mutation is passed on to offspring by the parent .the second mutaion has to occur in the offspring in a somatic cell for theinherited Rb cancer to occur.
the explanation i read is that the Two-hit hypothesis proved correct for Rb as it was shown that a single gene13q14 was inactivated in families that have inherited form of Rb.the initial mutation /loss of functionis inherited in an AR TRAIT and does not initself lead to development of cancer.however, cells in this single allele is inactivated will have a greater probability of developing cancer if another mutation inactivates the 2nd allele to give a homozygous state
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| fanaye
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hi all saturday how did it go mine was fine with UW
AS to the retinoblastoma Dominant as it is already mentioned by
dr ruman since it is inhrited through the germ line patient will develope the tumor bilaterally and wii transmit to his next generation
even if he has only one mutated tumor supressor gen(one hit) it is shure hi is going to have mutation in the other supressor gen (second hit) and develope the tumor
tumor supressor- two hit-loss of function- development of mutation
oncogen- one hit-gain of function -development of mutation
i dont know if this might help
good study time for all
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| fanaye
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the november group how are you doing all ? how is your revision going
in my case a little nervous thinking about the exam still doing UW
may peace will be with every body .
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| sfk
Forum Elite
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Posts: 300
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thanks cleopatra i spent some time with the books as well. its clear now. u guys rad up oncogenes etc too, thats high yield stuff.
fanaye, we are all going to get even more nervous. but hopefully we'll hold on till the end..
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| shohreh
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hi my friends
how was your weekend...mine was nothing ...i have to do my weekend program today and tomorrow,and i know i can do it
i am still reading pharmacology..it seems good but i have to read it again to memorize it
enjoy your time
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| shohreh
Forum Senior
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ATTENTION PLEASE
i think i am the last one who goes to take the exam..please don,t leave me alone..please when you take your exam give your experiance to others in this page...thank you
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| fanaye
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nice to hear from the group, you said your weekend was nothing what about today how is pharma what about UW.My weekend was fine still on UW my score 75% and i dont know what this score means any ways trying to make the best out of the Q bank as i said i am using it as a study tool.
even though you are the last person to take the USMLE from the november group i am shure every body is going to share Exam Expriances dont worry
good and effective day for all
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| shohreh
Forum Senior
Topics: 17
Posts: 308
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hi fanaye
until now my today goes well...reading cns pharmaco..but don't memorize them..now i want to back to my notes and memorize them and at evening am going to do uw
you are doing great in UWis this your first round in uw?
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| fanaye
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yes it is my first round i almost half way of the Q bank i am doing it subject wise. Thank you for your encouraging words i thought my score is not good one, Thank you any ways.
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