Congenital atresia of left main coronary artery.

We report a rare case of congenital atresia of left main coronary artery in an elderly male presenting with angina and positive stress thallium test. Coronary angiogram showed absence of left main coronary artery in the left aortic sinus. Collaterals from right coronary artery supplied left anterior descending artery and left circumflex artery territories. Despite collaterals, the left anterior descending and left circumflex arteries were rudimentary. Poor size of left-sided arteries precluded any surgical revascularization which is the treatment of choice in this rare entity.

Alterations in brain tumor DNA detected by a fingerprinting probe.

We used a novel DNA fingerprinting probe O-chi-1 (ref. 1) to detect differences in the hybridization pattern of brain tumor DNA and paired normal tissue of a given individual. Representatives of meningiomas (two), glioblastoma multeforme (three) and astrocytoma (one) were studied. Alterations, which included amplification as well as the loss of a normal band in tumor DNA, were observed in four of the six tumours. While the increased intensity of a band can be taken to imply increased copy number, the disappearance of bands could either be due to loss of DNA sequence or rearrangement resulting in different sized bands.