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Biomedical subjects

C D Pfaffenberger

Publications and source records attributed to C D Pfaffenberger.

At least 19 recordsLinked to original sources
PubMed1986

Analysis of 5-fluoro-2'-deoxycytidine and 5-trifluoromethyl-2'-deoxycytidine and their related antimetabolites by high-performance liquid chromatography.

An isocratic, ion-paired, reversed-phase high-performance liquid chromatography technique for the quantitative determination of 5-fluoro-2'-deoxycytidine (FdCyd) and 5-trifluoromethyl-2'-deoxycytidine (F3methyldCyd) and their related antimetabolites is described. Extraction and purification of these compounds from DNA, RNA, and free pools is reviewed diagrammatically. Total analysis time including quantitation of DNA and RNA primary constituents is 45 min. Average combined recoveries for prodrugs and antimetabolites is above 90% with standard deviations of 0.07 and 0.58 and average precisions of 5.51 and 8.30% for FdCyd and F3methyldCyd, respectively. Average coefficients of variation were 3.8 +/- 0.5% for FdCyd and 7.7 +/- 1.0% for F3methyldCyd. Limits of detection were approximately 1 pmol for unlabelled prodrugs and antimetabolites. FdCyd, when generally tritiated with a specific activity of 18 Ci/mmol, was detected in the 5 X 10(-15)-20 X 10(-15) mol (fmol) range depending on sample condition.

Buffers↗
PubMed1983

Death and injury caused by methyl bromide, an insecticide fumigant.

Methyl bromide (MeBr) is used as an insecticide fumigant. Four deaths and three recent hospitalizations have resulted from exposures to MeBr in Dade County, FL. Six cases occurred during burglaries of tented houses over a nine-month period. In four lethal exposures, the symptoms of nausea, vomiting, and malaise preceded fulminant respiratory failure. Two of these also had seizures, delirium, and agitation. Serum or plasma bromide ion levels ranged from 40 to 583 mg/L. Pulmonary edema, hyaline membranes, and hemorrhagic alveolitis were present at autopsy along with varying degrees of cerebral edema. The nonlethal exposures resulted in symptoms of conjunctival irritation, headache, or nausea. Plasma bromide concentrations varied between 17.5 and 321 mg/L. Methyl bromide characteristics, use, morbidity, and mortality in Florida during the past 25 years are reviewed. Remedies for illegal entry are proposed.

Adolescent↗
PubMed1982

Long-term variation study of blood plasma levels of chloroform and related purgeable compounds.

Values for circulating plasma chloroform of 25 white adult females were monitored for 6 months during the first phase of a four-phase long-term variation study. The data suggested four major exposure categories. Category I (20%) had average chloroform levels less than 10 ppb and variation ranges less than or equal to 10 ppb. Category II (24%) had average levels of 10-25 ppb and ranges of less than or equal to 10 ppb. Category III (20%) had average levels of 10-25 ppb and ranges greater than 20 ppb. Category IV (28%) had average chloroform levels of greater than 25 ppb and variation ranges greater than 20 ppb. Although the participants had been carefully screened to exclude incidents of occupational and recreational exposure, three subjects in category IV experienced obvious incidences of acute exposure to either chloroform or a chloroform precursor. In these situations circulating plasma chloroform levels were between 1655 ppb and 4000 ppb.

Adult↗
PubMed1981

High performance liquid chromatographic determination of cyanuric acid in human urine and pool water.

A reverse phase high performance liquid chromatographic (HPLC) assay for the quantitative determination of cyanuric acid (CA) in urine and water is described. For purification, samples are passed through a pre-activated reverse phase C18 column. The effluent is dried by lyophilization, and the residue is reconstituted in hexane-washed water and then passed through a prewashed Dowex-1 column. The effluent is again dried by lyophilization, and the dry residue is extracted with hot dioxane. The solution is cooled to ambient temperature and centrifuged. The supernatant liquid is removed, dried under a nitrogen steam, and dissolved in water for final extraction by reverse phase chromatography. This effluent is dried, dissolved in the sodium phosphate monohydrate in methanol (pH 7.0) mobile phase, and injected into a pre-equilibrated chromatographic system. An external standard is used for quantification by peak height comparison. A sample of HPLC column effluent is collected, dried, dissolved in methanol, and used for mass spectrometric confirmation by a solid probe insert procedure. Average combined recovery determined at 1.0, 5.0 and 10.0 micrograms CA/mL is 103 +/- 3% with an average coefficient of variation of 8.6%. Standard deviations for the 3 concentration levels are 0.04, 0.58, and 0.76, respectively, with average precisions of 4.28, 10.92, and 7.61%. The limits of detection are approximately 0.05 micrograms/mL for urine and 0.1 micrograms/mL for swimming pool water. Recorder response to CA is linear over the concentration range 1-10 microgram/mL.

Chromatography, High Pressure Liquid↗
PubMed1980

Distribution of volatile halogenated organic compounds between rat blood serum and adipose tissue.

A 31-day rat-dosing sequence was used to study some aspects of the physiological distribution, metabolism, storage and rate of elimination of chloroform, trichloroethylene, carbon tetrachloride and bromodichloromethane from rat adipose tissue and blood serum. Data points were collected nine times during the dosing period and twice after dosing had ceased. Purge/trap/desorb methodology was employed using a liquid sample concentrator, a gas-liquid chromatograph and a Hall electrolytic conductivity detector in series. Compound identities were confirmed using a GC/MS analytical system. For these volatile compounds, tissue levels fluctuated but did not indicate increased storage with time. Adipose tissue to blood serum levels never differed by more than a factor of three. Within 3-6 days after dosing was terminated, practically all of the halogenated compounds had left the examined tissues. Metabolic conversion of trichloroethylene and carbon tetrachloride into chloroform and/or a chloroform precursor was observed; bromodichloromethane-dosed animals did not have serum chloroform levels exceeding those observed for the control animals.

Adipose Tissue↗
PubMed1976

Gas chromatographic study of free polyols and aldoses in cataractous human lens tissue.

An analytical procedure for the qualitative and quantitative analysis of human lens tissue for polyol and aldose content is described. Profile samples are obtained by direct derivatization of lyophilized lenses. The components are analyzed as per-O-acetylpolyols (from the polyols) and per-O-acetylaldononitriles (from the aldoses). This procedure converts each component into a single derivative and terminal dissymmetry for each aldose is retained. The derivatives form in quantitative yield, give good chromatographic peaks, are thermally stable and readily volatilized. They are not subject to adsorption on gas chromatographic columns and are suitable for both qualitative and quantitative analytical studies. Six non-cataractous lenses and fourteen lenses from patients with senile cataract (in seven instances complicated by diabetic pathology) were analyzed. Thermostable borosilicate glass open-tubular capillary columns, coated with the nonpolar phase SE-30, and containing dispersed particles of silanized silicic acid, were used for the gas chromatographic separations. The results are discussed in relation to what is known from earlier studies of human and animal cataracts. A gas chromatographic method for determining the polyol and aldose excretion levels of controlled diabetics is also reported along with a typical metabolic profile.

Cataract↗
PubMed1975

High-resolution biomedical gas chromatography. Determination of human urinary steroid metabolites using glass open tubular capillary columns.

Recently developed analytical procedures for the qualitative and quantitative analysis of human urine for major and minor steroid metabolites are described. Steroid profile samples were obtained by enzymic hydrolysis with beta-glucuronidase and sulfatase. Methoxime-trimethylsilyl ether derivatives of steroid metabolites were prepared; the recommended procedure converts all ketone groups (except the 11-one group) into methoxime groups and all hydroxyl groups into trimethylsily ether groups. These derivatives are thermally stable, readily volatilized, not subject to dehydration or adsorption on gas chromatographic columns, and suitable for both quanlitative and quantitative analytical studies. Thermostable glass open tubular capillary columns, coated with the non-polar phase SE-30, and containing dispersed particles of silanized silicic acid, were used for the gas chromatographic separation. Illustrations of profiles for normal female and male subjects, and patients with a testosterone-secreting ovarian tumor, congenital adrenal insufficiency and a dehydroepiandrosterone-secreting adrenal tumor are included.

Adrenal Gland Neoplasms↗