Steady-state kinetics of substrate binding and iron release in tomato ACC oxidase.

1-Aminocyclopropane-1-carboxylate oxidase (ACC oxidase) catalyzes the last step in the biosynthetic pathway of the plant hormone, ethylene. This unusual reaction results in the oxidative ring cleavage of 1-aminocyclopropane carboxylate (ACC) into ethylene, cyanide, and CO2 and requires ferrous ion, ascorbate, and molecular oxygen for catalysis. A new purification procedure and assay method have been developed for tomato ACC oxidase that result in greatly increased enzymatic activity. This method allowed us to determine the rate of iron release from the enzyme and the effect of the activator, CO2, on this rate. Initial velocity studies support an ordered kinetic mechanism where ACC binds first followed by O2; ascorbate can bind after O2 or possibly before ACC. This kinetic mechanism differs from one recently proposed for the ACC oxidase from avocado.

Factors that influence state funding for mental health research.

A 50-state survey was conducted to identify the extent of and the factors associated with states' funding of mental health research. Of the 49 states responding, 28 funded mental health research. Funds for research represented about .3 percent of total state expenditures for mental health. More populous states were more likely to fund mental health research. A moderately high correlation was found between state funding for research and federal research funding, and a modest but statistically significant correlation was found between state funding for research and total state expenditures for mental health. No correlation was found between state mental health research funding and state per capita mental health expenditures. Political environments supportive of mental health research were characterized by budget stability, articulate and committed leaders, and active citizen advocacy.

Intra-aortic balloon pumping in infants and children.

From November 1981 to November 1982, intra-aortic balloon pumping (IABP) was used after surgery in eight patients who were from 6 weeks to 6 years old and who weighed from 4.2 to 16.2 kg. In seven patients, specially constructed intra-aortic balloons with 2.5 and 5.0 ml volumes mounted on No. 5F catheters were used. In the largest and oldest patient, a two-chamber 10 ml balloon was used. The pumping module used was the Datascope System 82. Effective diastolic augmentation of arterial pressure was accomplished in seven of the eight patients and suprasystolic diastolic augmentation was accomplished in four. The two youngest and smallest patients are the only long-term survivors. There were two short-term survivors who died 5 and 10 days after successful IABP. In only one patient was there no appreciable effect of IABP. Miniaturization of the equipment has permitted IABP to be used effectively in pediatric patients.