Wednesday, August 20, 2008


Finally on last Thursday I gave my thesis a push and the lab work has started since then. After I finally talked to my thesis supervisor face-to-face and talked to some lab technicians for their advice, I decided I can't delay it any longer and got it moving right away. I got the things I needed ready and went out to collect water sample from hawkers at Chow Kit.

If you were wondering why am I using water and soil sample instead of rat's brain and cat's feces as mentioned earlier (Did I mention it here?), the reason being - my supervisor wanted it. I know it's a poor excuse, but if you were me, you'll understand how difficult it is to go against what your supervisor insisted. Yes, she insisted on water and soil sample from Chow Kit since the beginning of our discussion, even if both of us didn't know how to do that, not even the method to collect the sample.

Hence as I talked to the lab technicians as suggested by my supervisor, all of them responded:"Oh, this is a difficult topic!" or "Hmm..the method is very difficult.."

It's not the point of difficulty in conducting this research that troubles me, but the fact that none of the lab technicians in Parasitology Department of Medical Faculty who worked there for 20 or 30 years know about the methods for those samples. We discussed and decided to use some of the basic method to screen the samples. When you talk about "basic" methods, it's always less sensitive and specific.

And till now I still don't understand why use water and soil sample by right cat is the definitive host for this parasite and only cat can defeacate this parasite in oocysts (egg) form in its feces. If we were to check for the prevalence of this parasite in Chow Kit, isn't it suppose to check for its presence from cat feces found in Chow Kit? The probability of getting a positive result would be higher. Of course, it's not wrong to get a negative result which means Chow Kit is free of Toxoplasma gondii, but will the result be reliable coming from water and soil sample? Water and soil sample will only be contaminated and positive for this parasite only if it's contacted with cat feces. Hence isn't checking out cat feces is more logical?

Anyway, I have collected 3 bottles (Schott, 250 mL) of water sample from 3 different hawkers in Chow Kit and am in the process of screening the water. It has become my routine everyday since then:

1. Wake up and convince myself that I'd rather sleep less to catch the last bus than to walk to campus.
2. Reach campus and have a quick breakfast then go to lab.
3. Pipette the water sample from Schott bottle into 4 centrifugation tubes and centrifuge them at 1500 rpm for 5 minutes.
4. Get rid of the supernatant and pipette the sediment to perform direct smear on microscopic slides and cover with cover slips.
5. Screen under light microscope.

The last step can take up to 2 hours, just for 4 tubes (2 drops of sediment each, hence 8 slides to screen within 2 hours). I'm trying to increase my screening speed so that I can screen more slides and finish of the water sample I've collected since last week to collect new water sample again. There are loads of hawkers in Chow Kit! And I haven't started with the soil sample yet!

Well, after the 5th steps, usually it'll be lunch time. So I usually go to campus cafe for a quick lunch then head back lab.

Afternoon (right after lunch):
1. If the centrifugation tubes are running out or the disposal tank is kinda full, I'll wash the equipments before starting off my afternoon screening session. I have to thank Jun Hoe for his post which created awareness in me on why new people in the lab should volunteer to help up with the management of the lab, or at least, clean up our own mess.

2. After putting the washed equipment in the oven, I'll start the water-sample screening procedure again. Usually it lasts till around 5pm or slightly before that because the lab technicians are getting ready to close the lab and call it a day.

Everyday I walked out of the lab, feeling relieved that at least my lab work is progressing and I know what to do next. My work is indeed very easy. It is no doubt tiring my eyes because all I do most of the time in lab is to look into microscope and screen the slide up-down, next roll, up-down, next roll... for that mysterious oocysts. You got the picture. But it isn't that tiring because I've learnt how to look into the microscope using both eyes. Gosh it took me this long to find my "spot" for perfect vision, haha ;-)

Like Wey Wen said, looking into microscope to observe microorganisms is fun. It is true. But at least, let's hope that the parasite will show up fast, OK? I've found nothing after 60 slides! Most of them are plain dirt. Anyway, I'm still keeping myself optimistic about my lab work. That's a way to enjoy one's lab work, no? =)


pris said...

wow...i really admire one who can just bear the sanity-gripping-at-the-edge-of-my-big-hair scenario of looking for stuff under the microscope.. little micro stuff...and like for hours...???!!!for me, even 1 slide is hardly bearable...thumbs up for u then... keep it sane..=D

all da best 4 ur thesis..

Cher Linn Tang said...

Haha, thanks Prisca. But really, if you have a well-prepared slides, observing it under microscope is fun and the art is amazing. God can be that delicate in His every creation, you know ;-)