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Biomedical subjects

J R Shipe

Publications and source records attributed to J R Shipe.

25 records · Page 2Linked to original sources
PubMed1979

Plasma polyamines determined by negative-ion chemical ionization/mass spectrometry.

We have developed an accurate and highly sensitive gas-chromatographic/mass-spectrometric procedure for determining di- and polyamines (putrescine, spermidine, and spermine) in plasma and erythrocytes. Deuterium-labeled analogs of putrescine, spermidine, and spermine were synthesized for use as internal standards. Trifluoroacetyl derivatives of the polyamines were formed during the procedure and then detected with negative-ion chemical ionization/mass spectrometry in combination with multiple ion monitoring. Limits of sensitivity ranged from 0.25 to 1.0 pmol of analyte injected into the instrument.

Chromatography, Gas↗
PubMedDate not supplied

Serum and urine polyamines in cancer.

Polyamines in serum and urine have been found to be elevated in patients with cancer. A variety of methods employed for these measurements are discussed. Normal values obtained by the most recent methods are presented, and a survey has been made of polyamine levels in cancer patients.

Chromatography, Gas↗
PubMedDate not supplied

A comprehensive gas chromatography procedure for measurement of drugs in biological materials.

Procedures have been developed for the determination in serum and urine of 21 drugs which include all of the barbiturates, methyprylon, glutethimide, meprobamate, propoxyphene, methaqualone, primidone, diphenylhydantoin, methadone, codeine, morphine, amphetamine and methamphetamine. The method involves pipeting 1.0 ml of serum or urine into an extraction tube, adding an internal standard together with either a pH 4.9 or pH 8.3 buffer and extracting with chloroform. The drugs in the extract are concentrated by exaporation of the organic layer and identified and quantitated by gas-liquid chromatography (GLC) using a column packed with 3 percent OV 17. GLC analysis times are kept below seven minutes by using temperature programming which allows good separations of drugs of widely varying volatilities. All calculations are based on peak areas determined by an electronic integrator. Losses of drugs during extraction, evaporation and chromatography steps are compensated for by the use of internal standards. Actual extraction efficiencies of drugs from serum or urine range from 75 to 100 percent although recoveries, based on standards carried through the entire procedures, are quantitative. Precision (s.d.) based on replicate determinations is approximately plus or minus 0.2 mg per dl.

Alkaloids↗
PubMedDate not supplied

Adaptation of EMIT drug assays to a random-access automated clinical analyzer.

Enzyme multiplied immunoassay technique (EMIT) assays for theophylline, carbamazepine, phenytoin, phenobarbital, valproic acid, acetaminophen, gentamicin and tobramycin, have been adapted to the Technicon RA-1000 random access analyzer. Working reagents are stable for a period of at least one week, and calibration need only be performed when preparing fresh reagents. Between-day precision ranged from 2.2 to 5.5 percent and correlations with similar EMIT assays performed on a centrifugal analyzer were satisfactory. Excellent results were obtained on proficiency testing samples when analyzed for theophylline, phenobarbital, phenytoin and acetaminophen. The procedures have been adapted to emergency testing of these four drugs.

Autoanalysis↗
PubMedDate not supplied

Drug monitoring in the neonate.

Drug monitoring has recently been extended into the neonatal population largely owing to improvements in analytical techniques. This important area of study represents a wide diversity of patients,-from mature infants to low-birth weight infants owing either to premature birth or intrauterine growth retardation. Neonates provide a highly variable population base which undergoes rapid changes in rate of absorption, metabolism, and elimination of drugs during the first weeks of life. Rational drug administration at this time can be very difficult. Drug monitoring in conjunction with effective therapeutic ranges can be of great assistance to the physician.

Drug Interactions↗
PubMedDate not supplied

High performance liquid chromatographic separation and fluorescence detection of polyamines in plasma and erythrocytes.

A high performance liquid chromatography has been adapted to the measurement of putrescine, spermidine and spermine in plasma and erythrocytes. Detection was by fluorimetry using o-phthalaldehyde which formed fluorophores with the polyamines. Sensitivity of the method was better than 10 pmol of each polyamine, and recovery averaged 93.9 percent. The precision of the analysis was two percent (R.S.D.). Good correlation was obtained with a reference chemical ionization gas chromatographic-mass spectrometric procedure. Reference intervals for polyamines in both plasma and erythrocytes were estimated on the basis of 25 normal volunteers.

Adult↗