Jim Costello

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The methods used for determination of oxalate in blood are reviewed, and the advantages and disadvantages of the two basic approaches--direct methods and in vivo isotope-dilution techniques--are compared. Possible reasons for the previous discrepancies between direct and isotopic methods are discussed, as are the effects of protein binding, sample handling,(More)
Initial studies had revealed that the bioactivity of nerve growth factor (NGF) in sonicates of adult rat hippocampal formation (HF) is several-fold greater in their pellet than their supernatant fractions. Such observations have prompted an analysis of NGF antigen (NGF-Ag) contents in pellets and supernatants from a variety of adult rat CNS tissues, both in(More)
There have been several recent methods for determining serum oxalate in man (1-8), but reported normal values have ranged from 0.3 to 14 mg/liter. Recently Knowles and Hodgkinson (6) reported an enzymic method for oxalate determination in human serum by use of oxalate decarboxylase (EC with subsequent colorimetric determination of the evolved CO2.(More)
Using D-[1-(14)C]glucose as a tracer, renal glucose utilization and production was measured in chronic metabolic acidosis and alkalosis in dog kidney in vivo. In six experiments in acidosis, mean total renal glucose production was 4.447+/-1.655 SE mumol/min and glucose utilization was 4.187+/-0.576 SE mumol/min. In five alkalotic experiments it was found(More)
Six siblings with Bartter's syndrome were studied. Increased urinary immunoreactive prostaglandin E (iPgE) was corrected by administration of the prostaglandin synthetase inhibitors, indomethacin, ibuprofen and meclofenamate. In addition, plasma potassium rose, plasma renin activity and angiotensin resistance decreased, and the exaggerated natriuresis(More)
Serum and urinary oxalate was determined in 9 normal subjects, ingesting 8 g of ascorbic acid daily. Serum oxalate levels increased to 310% of control values during supplementation. Plasma ascrobate levels reached a mean value of 3.6 mg% far exceeding the previously reported plateau level of 1.8 mg%. Urinary oxalate gradually increased during ascorbate(More)
A simple method is described for the measurement of urinary oxalate. Oxalate decarboxylase is coupled with NAD+ requiring formate dehydrogenase and the result recorded spectrophotometrically. Accurate determination can be carried out either on urine or a citrate extract or urine. Using the citrate extract procedure, the urinary samples can be stored for at(More)
Daily ingestion of 8 g of pure ascorbic acid by 8 normal subjects for 7 days did not, in contrast to previous reports in the literature, significantly alter urinary or plasma oxalate during or after ingestion. When urine with raised ascorbate values was heated at 100 degrees C for 30 min, a significant increase in urinary oxalate concentration was observed.(More)