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Frequent detection of infectious XMLV in human cultures from mouse xenografts

Discussion in 'XMRV Research and Replication Studies' started by Jemal, Jun 30, 2011.

  1. eric_s

    eric_s Senior Member

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    Ruth, come on, you don't know it ;). At this moment nobody really knows something for sure, i think. HTLV (Ruscetti) and Hepatitis C (Alter) were not contaminants either. That does not prove anything about XMRV of course, but these people are no beginners. We are voting in the Vivint contest and donating to the WPI so they can hopefully afford any type of equipment they need. But if i see how other groups fail to find XMRV i think the WPI might have made the right choices as far as the methodology is concerned. I'm also worried about contamination, but i think they can rule this out without having to change the PCR method, by studying blinded samples that were collected and handled in exactly the same way.
  2. RedRuth

    RedRuth Senior Member

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    Of course I don't know, I'm just saying on the evidence, contamination is most probable at the moment. Isn't it true though that the WPI don't think PCR is the best way of detecting XMRV? BTW, your lab is only as good as your post docs/PhD students/research assistants, they're the ones that do the actual work, the big names rarely do any actual lab work anymore, when they say ' ...... we did PCR' they mean the Royal 'we' ie someone else did it.
  3. Bob

    Bob

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    That's only if you are basing your conclusion on a simplistic count of the number of positive and negative studies, and a simplistic evaluation of some of the contamination theory studies.

    If you look deeper into the subject, then you would realise that there are so many reasons why contamination is not the most probable answer, although I do agree that without first hand knowledge of the WPI's methodologies, it is a possible answer.

    There seems to be the massive question of latent viruses, leading to extremelly low copy numbers, which none of the blood tests have been able to resolve.

    Mikovits uses a specific method of culturing to increase the copy numbers.
  4. RedRuth

    RedRuth Senior Member

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    The Singh study used the same method and the Levy study used a very similar culturing method.

    I don't see why, contamination with an infectious virus can account for all the WPI results. The fact that they use cells that have been found to be infected in other labs (LnCAP) and the VP62 construct could account for the findings.
  5. Bob

    Bob

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    But we already know that neither Singh or Levy used the same methodology as the WPI.
    And if they both did culture (can't remember the details) then they didn't culture for anywhere near the same number of days as Judy Mikovits.
    But that doesn't matter anyway, if they didn't replicate all of the other variables.

    Yes, contamination would be a simple answer, but not necessarily the correct answer.
    Anyway, we've already rehearsed all of the arguments, so I'm not going to repeat them again.

    Have you not thought about XMRV infection in all of those substrates, and how XMRV appears to have so easily contaminated so many labs?
    How would they possibly have avoided contamination of vaccine substrates with XMRV? Especially as they don't even seem to have been testing for it up until now.

    And what happens once XMRV is inside the human body?
    It becomes latent. (i.e. very difficult to detect.)

    There's a lot more work to be done.

    Did you say that not many labs have detected XMRV? That's not true. Quite a number of researchers have found XMRV in prostate cancer, including Switzer at the CDC. And in Singh's case, she has also found it in breast cancer samples.
    Dr Singh has also detected XMRV in the healthy population (at the same rate as the WPI) but only in tissue, not blood.
    Switzer could also detect XMRV in tissue but not in blood.
    Does this not lead you to ask questions, with your scientifically curious mind, rather than draw early conclusions?
  6. leela

    leela Slow But Hopeful

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  7. RedRuth

    RedRuth Senior Member

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    The Singh study did, they say ........... with extensive help from Frank Ruscetti and they cultured for at least 6 weeks.

    I think XMRV is interesting and I think it's potentially a health risk which is why I think it's a good idea to screen blood and cell lines used for vaccines. I'd be foolish not to be at least mildly concerned given that I actually work in a lab with cell lines. I've always thought that we may be too blase about cell lines and I'm super safety concious with them.
  8. Mya Symons

    Mya Symons Mya Symons

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    Since XMRV originated from recombination of nude laboratory mouse MuLv's, it had to have started out in a lab FROM lab contamination. Doesn't this mean that it is possible it is both laboratory contamination and an infectious human virus? Why is it often talked about like one is mutually exclusive from the other? Even if the Whittmore Peterson lab is contaminated, this does not necessary mean that people are not infected with XMRV. It has been said that the XMRV antibody tests are picking up another virus; however, as far as I know, no one has adequately explained what virus that would be. What if the antibody tests are correct (true positives), but some of the culture positives were do to contamination? So what. This may not be evidence in itself that people are not infected with this virus.
  9. RedRuth

    RedRuth Senior Member

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    It could be both a cell line 'contaminant' and an infectious Human virus, it's certainly the first and the big question now is, is it the latter, I don't think anyone is arguing that XMRV isn't a real virus. The take home message if you like of this paper is how easy it is to infect cell lines and how many cell lines are infected. If your cell lines are infected or your reagents are contaminated either with Mouse DNA or VP62 plasmid DNA then you will probably get false positives from patient samples.

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