1.   So it appeared obvious that in the absence of a known cause, any rational prevention strategy must involve partner reduction.

2.   Chlorine monoxide, a known cause of ozone depletion in the stratosphere above polar regions, has been discovered in the upper atmosphere over temperate latitudes.

3.   According to Laurie Richardson of Florida International University in Miami, only three of these coral ailments have a known cause.

4.   But most of the time, specialists said, there is no known cause.

5.   Despite years of research into things like the possibility of hormonal imbalances or vitamin and mineral deficiencies, there is no known cause or physical test for PMS.

6.   Gambetti ruled out most known causes of CJD.

7.   Hypertension is a known cause of diabetes.

8.   Instead of distant cures, why not dramatize the known causes of cancer?

9.   It also found that people who are depressed are more likely to smoke, a known cause of heart disease.

10.   It varies in severity and has no known cause and no cure.