Is it a good idea to handle reference samples from suspects and victims in the same period and in the same location?
In terms of forensic or clinical laboratory practice or any kind of practice in DNA laboratories, is it a good idea to handle many samples at the same time in a rush?
All right. You've heard the testimony about how Mr. Yamauchi sampled and then proceeded to test on June 14th twenty individual samples?
All right. Does that seem to you, in terms of ordinary laboratory practices--well, in your opinion, what do you think about handling all those samples in the time period he described?
All right. Let's turn to 1159-H. Now, you've heard testimony with respect to the practices of the LAPD crime laboratory personnel, Mr. Fung, Miss Mazzola and Mr. Yamauchi with respect to changing gloves. Are you familiar with that?
All right. Now, as a microbiologist and DNA laboratory director do you believe that analysts handling blood samples should routinely change their gloves between handling each item?
Especially with a technique like PCR. This is such a sensitive technique you might not even notice that you have a small amount of blood or even an aerosol of that blood on your glove, and unless you change the glove you can't eliminate the possibility that you might transfer that to the next sample.
KEY QUOTENow, in terms of laboratory paper, are you familiar with the testimony of Mr. Fung and Miss Mazzola that when the samples were brought into the LAPD laboratory and they were taken out of the plastic bags and put into the test-tubes that they did not change laboratory paper between handling those items?
Are you familiar with their testimony that when they took the swatches out of the tubes the next morning and scraped them out with a pipette on to a bindle that they did not change the laboratory paper between each item?
In your opinion are those sound laboratory practices in terms of the danger of cross-contamination?
That is going to create a shower of an aerosol which is going to fall down on that entire area and can easily be transferring DNA from one item to another.
KEY QUOTEIn terms of aerosols then, since that is one of our little logos, I take it--what was that you were saying about scraping the swatches out of the tubes?
Yes. That is going to flake the DNA and it is going to fall down on that area and it is not going to fall down right down straight onto the bindle. It is going to fall in that entire area.
We've heard some questions being asked in this trial such as you heard them, "Can DNA fly?" Have you heard that?
KEY QUOTEAll right. Now, when aerosols are created of these kind of particles in a laboratory do they just fall right to the ground or how long do they remain ambient in an atmosphere?
Are you familiar with Mr. Yamauchi's testimony that in processing the Rockingham glove and the LAPD items 47, 48, 49, 50 and 52 on the morning of June 14th, that he did not routinely change laboratory paper between those items?
And do you recognize this to be the evidence processing room where--and that table depicted as being the area where Mr. Yamauchi testified he processed the sample on the morning of June 14th?
And that was part of the basis for your testimony about those procedures that we just reviewed?
Now, did you go into the serology laboratory where Mr. Yamauchi and Mr. Matheson work?
Yes. In a laminar flow hood there is a screen along the bottom edge of the hood that draws a curtain of air down across that screen around to the back of the hood and then filters across something called a HEPPA filter and the HEPPA filter filters out microscopic particles, dust, certain bacteria and it cleans the air. So the idea behind the laminar flow hood is that there is--actually would have a window in the front that would lower down all the way down, with the exception of just enough room to stick your hands in about six inches. And then this flow of air flows across your hands and that basically forms a curtain of air that doesn't allow air from the room to get into the hood and it doesn't allow anything from inside the hood to get out and it is a hood that is frequently called a biosafety cabinet and the reason for that is it protects the analyst from being infected with--if there is an infectious agent, so in microbiology or virology we use these to protect an individual from being exposed to a dangerous agent they are working with. The other purpose of it is that it prevents anything from the outside from getting in and so the purpose of that, again from a microbiology standpoint, is you don't want things floating around on dust, such as spores or fungi, bacteria, DNA, things that attach to dust and float around, you don't want those contaminating what you are working with. Now, this hood here, the chemical fume hood, this hood was designed for the purpose of drawing fumes away from a chemist, so if they are working with something that has a noxious smell or something that has--can be toxin in terms of breathing that in, this hood is designed to pull air from the room into a hood and up an exhaust vent that goes out to the outside of the building. So the purpose of this is to draw air out of the room, through the hood and then out of the building and therefore pull the fumes away from the individual who is working.
Now, let me just show you two other pictures that we will mark as 1302 and 1303 of the area around this hood.
This is the work stations that are directed--that are found directly across the room from the hood that we just saw a picture of.
This is looking--you can see those lab coats on the work stations there looking back again across the room and the hood is located about halfway down the room there.
It creates unacceptable risk.
That is going to create a shower of an aerosol which is going to fall down on that entire area and can easily be transferring DNA from one item to another.
Especially with a technique like PCR. This is such a sensitive technique you might not even notice that you have a small amount of blood or even an aerosol of that blood on your glove, and unless you change the glove you can't eliminate the possibility that you might transfer that to the next sample.
We've heard some questions being asked in this trial such as you heard them, 'Can DNA fly?' Have you heard that?