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Biomedical subjects

J C Standefer

Publications and source records attributed to J C Standefer.

31 records · Page 2Linked to original sources
PubMed1979

Death associated with nitrite ingestion: report of a case.

The tissue concentrations of nitrite and nitrate found at autopsy of a case of intentional ingestion of nitrite salts have been reported. The percentage of methemoglobin and the serum nitrite concentrations are consistent with those reported for acute overdoses. We conclude that noth nitrite and nitrate salts may be identified in tissues from persons ingesting only nitrite salts and that a significant conversion to nitrate may result from oxidation of nitrite during the conversion of heme iron to Fe3+.

Adult↗
PubMed1979

Enzymic assay for lecithin in amniotic fluid.

We describe an enzymic method for determining lecithin in amniotic fluid. Phospholipase D from savoy cabbage is used to liberate choline from lecithin, and the liberated choline is oxidized to betaine and hydrogen peroxide by choline oxidase from Arthrobacter globiformis. The hydrogen peroxide forms a colored complex with phenol and 4-aminoantipyrene in the presence of horseradish peroxidase, and this color is measured spectrophotometrically. The method is relatively easy, precise, and accurate, requires less time and sample than other methods, and offers a reliable alternative to the lecithin/sphingomyelin ratio techniques for assessing fetal lung maturity.

Alcohol Oxidoreductases↗
PubMed1978

Enzyme immunoassay for gentamicin.

We describe a gentamicin assay in which a peroxidase-gentamicin conjugate competes with gentamicin for binding to a gentamicin antibody adsorbed to a polystyrene solid phase. The assay can be completed in 30 min and requires 50 microliter of diluted serum. The precision and accuracy are equivalent to that of a radioimmunoassay technique and the reagents are stable for several months.

Gentamicins↗
PubMed1977

Use of tetramethylbenzidine in plasma hemoglobin assay.

Plasma hemoglobin can be assayed by substituting 3,3',5,5'-tetramethylbenzidine for benzidine (a carcinogen) as the chromogenic reducing substance. Sensitivity, precision, and accuracy compare well with methods in which benzidine is used. Plasma inhibition can be accommodated by preincubation with hydrogen peroxide.

Benzidines↗
PubMed1975

Death associated with fluorocarbon inhalation: report of a case.

This case documents postmortem tissue concentrations of fluorocarbons in an individual whose inhalation of cooking spray vapors was well documented. The data presented here should contribute to the information base which will assist the pathologist in determining the cause of death in cases related to inhalation of these fluorocarbons.

Adolescent↗
PubMedDate not supplied

"Normal" insulin secretion: the goal of artificial insulin delivery systems?

Prehepatic insulin production can be determined from analysis of connecting-peptide behavior in the plasma. In the present study, we have determined prehepatic insulin production in six normal men throughout a day that included three typical 750-cal meals. Total insulin secretion for the 24 h was 45.4 U, secreted as 10.6 U with breakfast, 13.4 U with lunch, and 13.8 U with dinner. The remaining 7.6 U was secreted during the 9 h night at a rate of 0.85 U/h. At least 50% of the newly secreted insulin is known to be extracted by the liver during the initial transhepatic passage, so that total peripheral delivery can be estimated as approximately 22 U/day. Consequently, portal vein insulin levels are in excess of those seen in peripheral blood by at least 20 +/- 8 microU/ml in the fasted state, and by as much as 115 +/- 15 microU/ml in the 2-h postabsorptive state. The data suggest that insulinization of the liver, without peripheral hyperinsulinemia, may be a goal of artificial insulin delivery.

Artificial Organs↗