In situ bypass to the dorsalis pedis and tibial arteries at the ankle.

Over a three-year period (1984-1987), we performed 98 in situ saphenous vein bypasses to the tibial arteries in 89 patients. In 68 of these grafts, the distal anastomoses were above ankle level. All but one of these grafts were performed for limb salvage indications. Seven (10%) of these grafts were done in patients on chronic renal dialysis. In 30 grafts, the distal anastomoses were to the ankle level. Indications for surgery were risk of limb loss in all these patients, with tissue loss in 29 (97%). Six (20%) were done in patients on chronic renal dialysis. Operative mortality was 3% in both groups. Late mortality was 13% in the above-ankle group, and 27% in the ankle level group. Secondary patency for the above-ankle group was 97%, 85%, 81%, and 81% at 30 days, one year, two years, and three years. Primary patency was 91%, 67%, and 58% at 30 days, one year, and two years, after which the standard error is greater than 10%. Secondary patency for the grafts at the ankle level was 100% and 82% at 30 days and one and one-half years. Primary patency rates were 93% and 68% at 30 days and one year. In situ bypass grafts at the ankle level had patency rates equivalent to grafts with distal anastomoses above the ankle. Patients with distal bypasses usually presented with tissue loss and had a higher late mortality rate. Careful follow-up and operative intervention when changes in graft velocities or indices are recognized, markedly improves the durability of the in situ saphenous vein bypass.

Maize stripe virus: characteristics of a member of a new virus class.

An unusual filamentous nucleoprotein about 3 nm in diameter was consistently associated with maize stripe-diseased maize. Antiserum to purified nucleoprotein neutralized the infectivity of extracts from maize stripe-diseased plants suggesting that the nucleoprotein was the maize stripe virus (MStpV). The rate-zonal sedimentation pattern of the nucleoprotein on sucrose gradients was polydisperse between 51 and 70 S. CsCl isopycnic centrifugation of combined nucleoprotein zones from sucrose gradients resulted in a single band of 1.28 g/ml. The nucleoprotein consisted of 5.2% RNA and a single capsid protein of molecular weight 32,700 daltons. Large quantities of a noncapsid protein of molecular weight 16,300 daltons were also found in MStpV-infected tissue. MStpV was transovarially transmitted by its vector, Peregrinus maidis. Other species susceptible to MStpV in addition to Zea mays were Rottboellia exaltata and Sorghum bicolor. The similarities between MStpV and rice stripe virus are discussed. We conclude that these viruses represent a new virus class.