Abstract: A method for treating the vascular passage of a patient, damaged by procedures such as an endarterectomy which denude portions of the vascular passages of their endothelial cell linings, is disclosed. In this method, endothelial cells are isolated from the patient's own microvessels, the flow of blood through the patient's damaged vascular passage is interrupted, the endothelial cells isolated from the patient's microvessels are applied to the surface of the denuded portion of the patient's vascular passage in a density sufficient to provide covereage of at least about 50% of said denuded portion, and interruption of blood flow through the vascular passage is maintained for a period of time sufficient to allow the sodded cells to form an attachment to the vascular lining sufficient to withstand the shear created by resumed blood flow through the vascular passage.

Abstract: The invention provides restriction endonuclease Mf1 I capable of recognizing the base sequence as shown below on a double-stranded DNA molecule and cleaving the DNA chain at the arrow-marked positions, but has no such action when A is methylated5'--Pu.dwnarw.GATC Py--3'3'--Py CTAG.uparw.Pu--5'(wherein A represents adenosine, G guanosine, T thymidine, C cytidine, Pu adenosine or guanosine, and Py thymidine or cytidine). The restriction endonuclease is produced by culturing Microbacterium flavum IAM 1642, FERM BP-938 in a culture medium and recovering it from the culture.