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Four forms of cytochrome P‐450 were separated and purified to electrophoretic homogeneity from human fetal livers. These forms of cytochrome P‐450, termed P‐450HFLa, P‐450HFLb, P‐450HFLc and P‐450HFLd, were distinguishable from each other in their molecular weights, spectral properties, immunochemical properties and mutagen‐producing activities from promntagens. The molecular weights of P‐450HFLa, b, c and d were estimated to be 51,500, 49,000, 51,500 and 50,000, respectively. Antibodies to P‐450HFLa recognized P‐450HFLc but not P‐450HFLb or d, and antibodies to rat P‐448‐H (P‐450IA2) cross‐reacted with P‐450HFLb but not with other forms of cytochrome P‐450. The N‐terminal amino acid sequence of P‐450HFLc was highly homologous, but not identical, to that of P‐450HFLa. Each form of cytochrome P‐450 catalyzed mutagenic activation of aflatoxin Bl (AFB1), 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ) and 2‐amino‐6‐methyldipyrido‐[l,2‐a:3′,2′‐d]imidazole (Glu‐P‐1) at different rates. P‐450 HFLa showed activities to produce mutagen(s) from AFB1, IQ and to a lesser extent from Glu‐P‐1. P‐450 HFLb activated IQ at a faster rate than did the other forms. P‐450 HFLc produced a mutagen from AFB1 and Glu‐P‐1 but not from IQ. P‐450 HFLd did not activate these promutagens at significant rates.

A 64-year-old male presented with abrupt tetraparesis caused by a minor impact. Diagnostic images obtained on admission showed an aneurysmal bone cyst visible in the cervical spine at the fourth to upper sixth level, although the patient had been wearing a halo brace to diminish the symptoms. The vertebral body from the fourth to the sixth level was dissected, and this space was packed with a titanium cage filled with ceramic bone fragments mixed with fibrin glue. The combination of a titanium cage and an anterior locking plate can be made easily for anterior spinal fusion with enough rigidity to maintain the necessary space during fusion without any major support equipment. Both edges of the titanium mesh cage cut into the vertebral body to hold the cage in place. The other part, the titanium plate, makes it secure until ceramic bone fragments in the cage promote bony ingrowth for fusion.

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