Nucleoside diphosphatase and 5'-nucleotidase activities of soybean root nodules and other tissues.

Nucleoside diphosphatase and 5'-nucleotidase activities were both found to be very high in extracts of soybean (Glycine max L.) root nodules. Both activities increased early in soybean nodule development, prior to the rise in leghemoglobin, and both were found at equivalent levels in nitrogenfixing and nonfixing nodules. Based on a survey of other tissues, these activities were both highest in soybean nodules (1300 nanomoles per milligram protein per minute, nucleoside diphosphatase and 500 nanomoles per milligram protein per minute, 5'-nucleotidase), but they were not always associated with each other; in some tissues one was high and the other low. Neither activity correlated well with ureide production; both seem, rather, to be primarily involved in some other metabolic function. Both the nucleoside diphosphatase and 5'-nucleotidase of soybean nodules were soluble proteins, and neither appeared to be associated with plastids, mitochondria, or bacteroids.

Purification and characterization of a specific nucleoside diphosphatase from soybean root nodules.

A specific nucleoside diphosphatase was purified from the plant portion of soybean (Glycine max L.) root nodules. This enzyme is highly specific for nucleotide diphosphates; it is unable to hydrolyze nucleotide tri- and monophosphates or a variety of other phosphorylated compounds. It will, however, hydrolyze any nucleotide disphosphate tested. The pH optimum of the enzyme is about 7.5; it requires a divalent cation for activity; and it is neither inhibited nor activated by any of the metabolites tested. It appears that in vivo this enzyme would be very active, but its function is not clear.

Standard planning for new programs.

Health-care executives need to eliminate "gut feel" decisions with a standardized approach to business planning, such as Baxter Healthcare Corp.'s Healthcare Business Planner. The author illustrates how University Hospitals of Cleveland used this model to determine the feasibility of an ambulatory center dedicated to systemic lupus erythematosus.

Site of Synthesis of the Enzymes of the Pyrimidine Biosynthetic Pathway in Oat (Avena sativa L.) Leaves.

Heat-bleached oat (Avena sativa L. cv Porter) leaves lacking 70S chloroplast ribosomes have been used to demonstrate that four chloroplast-localized enzymes of pyrimidine nucleotide biosynthesis: aspartate carbamoyl-transferase, dihydroorotase, orotidine phosphoribosyl-transferase, and orotidine-5'-phosphate decarboxylase, are synthesized on cytoplasmic ribosomes. Two other chloroplast enzymes, carbamoyl phosphate synthetase, involved in both pyrimidine and arginine biosynthesis, and ornithine carbamoyltransferase, an enzyme of arginine biosynthesis, were also shown to be made on 80S ribosomes.

Organization of the pathway of de novo pyrimidine nucleotide biosynthesis in pea (Pisum sativum L. cv Progress No. 9) leaves.

The organization of the enzymes of de novo pyrimidine nucleotide biosynthesis in pea (Pisum sativum L. cv Progress No. 9) has been studied. The first three enzymes of the pathway, carbamoyl-phosphate synthetase, aspartate carbamoyltransferase, and dihydroorotase, are readily separable from one another; they are not part of a multifunctional complex. The final two activities of the pathway, orotate phosphoribosyltransferase and orotidylate decarboxylase, copurify and appear to be complexed in vivo. This organizational pattern is distinct from those reported for bacteria, yeast, and mammals. The differences in organization, in a pathway which is present in all organisms, make the pyrimidine biosynthetic pathway a very interesting candidate for evolutionary studies.

Subcellular localization of the pathway of de novo pyrimidine nucleotide biosynthesis in pea leaves.

The subcellular distribution of the enzymes of de novo pyrimidine nucleotide biosynthesis was investigated in pea (Pisum sativum L. cv Progress No. 9) leaves. Aspartate carbamoyltransferase, the committed step of the pathway, was found to be strictly confined to the chloroplasts. Dihydro-orotase, orotate phosphoribosyl transferase, and orotidine decarboxylase activities were also found only in the plastids. The remaining enzyme of the pathway, dihydroorotate dehydrogenase, was shown to be mitochondrial.

Health care 2000.

During the past two decades, the health care industry has become an economic giant growing from 6.1% ($42.0 billion) of the gross national product in 1965 to an estimated 10.7% ($354.6 billion) in 1983. The industry is now the nation's third largest. The underlying causes of this remarkable growth include an open-ended reimbursement system, insatiable demand, and the lack of traditional market forces that encourage efficiency. Unfortunately, the nation cannot continue to allocate an increasing share of its gross national product to health care, for to do so would mean that other important sectors of the economy would experience either retarded growth or a decline in real terms. By the 2000, fundamental elements of the health care system will have undergone a major metamorphosis which hopefully will result in a more efficient and effective allocation of the health care dollar. This article will offer an overview of the changes likely to occur in sections of the health care environment of major concern to the health care planner.

Data quality. An illustration of its potential impact upon a diagnosis-related group's case mix index and reimbursement.

The Health Care Finance Administration has developed a Medicare reimbursement methodology that will include an adjustment factor for hospital case mix. The patient classification scheme proposed for use in determining a hospital's case mix is the AUTOGRP Diagnosis-Related Groups (DRG) methodology developed at Yale University. The reliability of a case mix measure calculated using the DRG methodology is dependent on complete and accurate diagnostic and surgical data. The source of this data for the HCFA data base (MEDPAR) is the Medicare billing form, which is based on the patient medical record. Data from the MEDPAR file, the original medical record discharge order, and a reabstracted record are compared and analyzed for their effect upon DRG classification and the resultant Medicare reimbursement ceiling for one large teaching hospital. The study results show widely divergent diagnostic and surgical data that results in a significant variation in DRG classification and reimbursement ceilings.

DRGs may be raising false expectations.

The development of diagnosis related groups has fed what may be unrealistic hopes for their wide application.