Thursday, April 5, 2007

Two Men in a Sandbox

I met Professor Zhang Zuo-Feng, M.D., Ph.D by pure chance. We met while accompanying our toddler daughters in a sandbox.

Naturally, we struck a casual conversation about our girls. That was when I learned that he came to the U.S. some 11 years ago from Shanghai and he is a professor of epidemiology at the prestigious UCLA School of Medicine (located within walking distance from the park we were at). Having nothing to relate to professionally, and being that he is a medical doctor from China, I shared with him my personal experiences with Chinese hospitals and the stark contrast on the policy of disclosing relevant information to the patients.

We chatted and parted ways shortly thereafter. At home, curious about the kind professor, I looked him up in the UCLA David Geffen School of Medicine’s online faculty directory. He is apparently a professor of molecular epidemiology and thoracic oncology. His profile page contains a long list of medical publications that he had written or co-written in China and in the U.S. Three of the many medical writings, coincidentally, are tea related, and one of them is quite relevant to me as a wine drinker (relevant parts highlighted in maroon).

A coincidence? If I meet him again next time, perhaps I should invite him for some tea. Here is a guy who has reviewed tea in microscopic detail, so to speak.
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Lu QY, Jin YS, Pantuck A, Zhang ZF, Heber D, Belldegrun A, Brooks M, Figlin R, Rao J Green tea extract modulates actin remodeling via Rho activity in an in vitro multistep carcinogenic model.. Clinical cancer research : an official journal of the American Association for Cancer Research. . 2005; 11(4): 1675-83.

Abstract:
Center for Human Nutrition, University of California at Los Angeles, Los Angeles, CA 90095, USA.

Alteration of actin polymerization and loss of actin filaments is a marker of cellular dedifferentiation and early malignant transformation. To study this phenomenon, an in vitro human urothelial model consisting of two cell lines, HUC-PC and MC-T11, were incorporated into the study design. These two cell lines have different malignant transformation potential. The effect of green tea extract (GTE), a potential anticancer agent, on actin remodeling was investigated. Upon exposure to the carcinogen 4-aminobiphenyl (4-ABP), the untransformed HUC-PC undergoes malignant transformation whereas the transformed MC-T11 progresses from noninvasive to invasive tumor. GTE induces actin polymerization in MC-T11 cells in a dose-responsive manner, but this effect is less obvious in the untransformed, more differentiated HUC-PC cells, which natively have higher actin polymerization status. In contrast, GTE antagonizes carcinogen 4-ABP induced actin depolymerization and stress fiber disruption in HUC-PC cells. In MC-T11 cells, GTE inhibits 4-ABP induced motility by increasing cell adhesion and focal adhesion complex formation. The effect of GTE on actin remodeling seems to be mediated by the stimulation of small GTP-binding protein Rho activity, because C3 exoenzyme, a specific inhibitor for Rho, blocks GTE-mediated Rho activation and stress fiber formation in MC-T11 cells. This study shows that GTE exerts an effect on cytoskeletal actin remodeling and provides further support for the use of GTE as a chemopreventive agent.

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Mu LN, Zhou XF, Ding BG, Wang RH, Zhang ZF, Jiang QW, Yu SZ [Study on the protective effect of green tea on gastric, liver and esophageal cancers]. Zhonghua yu fang yi xue za zhi [Chinese journal of preventive medicine]. . 2003; 37(3): 171-3.

Abstract:
School of Public Health, Fudan University, Shanghai 200032, China.

OBJECTIVE: To assess the protective effect of drinking green tea on the development of gastric, liver and esophageal cancers. METHODS: A population based study was conducted in Taixing, Jiangsu province, including 206, 204, 218 cases, respectively, and 415 population controls.

RESULTS: Green tea decreased the development of gastric cancer risk by 40%. Dose-response relationships were observed between the length of time, concentration and quantity of green tea drinking and its protective effects on gastric cancer. For individuals who drink green tea for more than 250 g per month, the risk of gastric cancer reduced about 60%. Green tea might have protective effect on liver cancer. However, no protective effect of green tea was observed on esophageal cancer.

CONCLUSION: Green tea drinking might be a protective factor for gastric cancer. However, the protective effects of green tea on liver and esophageal cancer were not obvious.

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Mu LN, Zhou XF, Ding BG, Wang RH, Zhang ZF, Chen CW, Wei GR, Zhou XM, Jiang QW, Yu SZ [A case-control study on drinking green tea and decreasing risk of cancers in the alimentary canal among cigarette smokers and alcohol drinkers]. Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi. . 2003; 24(3): 192-5.

Abstract:
School of Public Health, Fudan University, Shanghai 200032, China.

OBJECTIVE: To explore the role of green tea in decreasing the risks of gastric cancer, liver cancer, esophageal cancer among alcohol drinkers or cigarette smokers.

METHODS: A population based case-control study was conducted in Taixing, Jiangsu province.

RESULTS: In Taixing city, identified cases of stomach, liver and esophageal cancers were chosen with informed consent. The numbers were 206, 204, 218 respectively. Controls were chosen from normal population having lived in the area for longer than 10 years, also with informed consent. Green tea drinking seemed to have decreased 81%, 78%, 39% risk for the development of gastric cancer, liver cancer and esophageal cancer among alcohol drinkers. It might also have decreased 16%, 43%, 31% on the risks of developing the three kinds of cancers among cigarette smokers. Interaction assessment showed that drinking green tea could significantly decrease the risk of gastric cancer and liver cancer among alcohol drinkers, with ORs of interaction item 0.23 (95% CI: 0.10 - 0.55) and 0.25 (95% CI: 0.11 - 0.57) respectively.

CONCLUSION: Habit of drinking green tea seemed to have significant protective effects on the development of both gastric and liver cancer among alcohol drinkers while, green tea also having some protective effect on esophageal cancer among alcohol drinkers and on three kinds of cancers among cigarette smokers.

10 comments:

Nikhil said...

Now I'm not a doctor or anything, but I can say that my HUC-PC's have been acting a lot more focally adhesive since I started drinking green tea. And my MC-T11's have been inhibiting Rho quite nicely.

Thanks, Dr. Phyll :)

~ Phyll said...

Nikhil -- funny! Proof enough that green tea is also good for our sense of humor.

Hobbes said...

A,

I firmly believe that there's no such thing as coincidence, just things that look like coincidence. :)

Thank you for posting his abstracts. It's far too removed from my field to make much sense, I have to admit!

I am always struck by the sheer number of authors that are attributed to medical papers. The three you showed were 9, 5, and 10 authors!

Furthermore, the professor that you met is credited 5th, 4th, and 5th author, respectively. That suggests he wasn't the primary researcher, nor even the primary researcher's supervisor. I wonder how much he would be able to talk about the papers when next you meet - it would be an interesting test of academic credibility to see if the > 4th author was familiar with something that he allegedly helped "author". :)


Toodlepip,

H

Ido said...

According to hobbes it is almost like:
How many professors does it take to write this sort of paper?
9 to write their names and 1 to make it up.

Is this for real...?
This guys are trying to justify their alcohol drinking habits - and lets face it phyll YOU TOO! :p

SilverNeedles Tea Reviews said...

numbers are easy to play with
and turn them into whatever toots your horn

stomach cancer is a really bad one, high mortality and especially because its detected late(except in japan).

stomach cancer is usually associated with diet: food nitrates, high salt, smoked stuff, and also very important: helicobacter pylori, alcohol, smoking.

on to the numbers:

japan is #1 incidence of stomach cancer in males at almost 77/100,000
(but they have a well developed system to detect and 'treat'=surgery - which really decreases their mortality : 5yr survival = 53%)

china is #3 incidence of stomach cancer in males at 44/100,000
(but their poor healthcare system which probably is not focused on detection like in japan, lowers their survival: 18% survive at 5 years)

usa: 8/100,000 ... (due to the low incidence detection is not top priority like for colon cancer, but still usa survival is 21-34% at 5 years).

from:
http://caonline.amcancersoc.org/cgi/reprint/49/1/33.pdf
observe i only put male gastric cancer rates,
,,

unfortunately in vitro experiments dont always conclude the same in vivo,
and,

cancer is multifactorial, its rarely due to 1 singular cause.

i highly doubt the statement:
"For individuals who drink green tea for more than 250 g per month, the risk of gastric cancer reduced about 60%"
or this which is most likely horridly absurd:
"Green tea drinking seemed to have decreased 81%, 78%, 39% risk for the development of gastric cancer, liver cancer and esophageal cancer among alcohol drinkers."

anyway, cancer is a complicated problem, genes and lifestyle have their say,
its unfortunate that others are trying to capitalize on this subject when not 1 thing will be able to cure all cancer.

im still going to drink my tea for its taste.

~ Phyll said...

Hobbes -- since I'm not a scientist, I don't know what the significance of a 4th or 5th author is on the paper.

Ido -- I don't have an alcohol drinking *hic!* habit.

Silverneedles -- thanks for the information. Look into for my next post shortly.

MarshalN said...

I too agree with Silver Needle here, and take such numbers with large grains of salt. Unless you see the full paper and look into how such numbers are arrived at and the methods chosen to get them, these numbers are almost meaningless. There are so many factors involved (such as, hypothetically, green tea drinkers tend to eat more healthily) that it is impossible to determine with any sort of certainty any sort of cause and effect.

~ Phyll said...

MarshalN -- can't agree more with you and Silverneedles in this discussion. Not going to such length as to look into how the numbers were arrived at et cetera, the first and foremost question that every layman should ask is: who funded the research?

As you may know, recently a UCLA researcher's credibility is under attack for saying that 2nd hand smoke is not as harmful as people think...then it was found out that his research was funded by tobacco industry's money.

Talk about a dashed appearance of impartiality.

There are tea-friendly research opinions out there that are funded by the tea industry as well.

Hobbes said...

I think it's more a case of it being a might big research band-wagon with plenty of room for people to jump on. , rather than actual aggressive marketing/funding.

"Tea in health" has plenty of topics for research, plenty of "low-hanging fruits", plenty of insubstantial, intercorrelated conclusions that are hard to disprove. Do a Google Scholar search on this subject and you'd need a month to read through the first page of hits.


Toodlepip,

H :)

Dr.Gray said...

Just another reason to splurge on some high quality green tea.