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Biomedical subjects

B D Andresen

Publications and source records attributed to B D Andresen.

At least 19 recordsLinked to original sources
PubMed2000

Restoration tactics for seriously corroded Cu and Cu-alloy firearms evidence.

A cleaning procedure for seriously weathered or corroded bullets and cartridge casings was developed and implemented for evidence specimens from a multiple homicide. The restoration protocol entailed successive treatments with increasingly aggressive chemical solvents and cleaning solutions while monitoring the progress of the method by optical microscopy. Treatment of worst-case, Cu-alloy jacketed bullets and casings resulted in reconditioned specimens that subsequently underwent successful firearms examinations.

Journal Article↗
PubMed1997

A possible chemical explanation for the events associated with the death of Gloria Ramirez at Riverside General Hospital.

The events associated with the death of Gloria Ramirez at Riverside General Hospital on 19 February 1994 have been portrayed as a major medical mystery. A potential chemical explanation for this incident has been developed. The hypothetical scenario depends upon the oxidation of a common solvent, dimethyl sulfoxide, through dimethyl sulfone to dimethyl sulfate. The latter compound is a volatile and highly toxic agent that can be quite hazardous to humans in small amounts. It is also environmentally nonpersistent. Much of the mystery surrounding the circumstances at the hospital may be explainable if this postulated metabolic pathway took place at the time of the emergency room incident. Although dimethyl sulfate was not detected in any analyses pertinent to this event, there are plausible scientific explanations to account for that fact. The sulfate anion, a hydrolysis product of dimethyl sulfate, was measured at an appreciably elevated concentration in Ramirez' blood. The descriptions of the symptoms of the hospital-staff victims appear quite consistent with dimethyl sulfate exposures. This paper attempts to make some sense of the reported data and eyewitness accounts, and perhaps provide new insight for any future research that could further explain this reported occurrence of toxic exposure.

Blood Chemical Analysis↗
PubMed1995

Comprehensive forensic analyses of debris from the fatal explosion of a "cold fusion" electrochemical cell.

Selected components of explosion debris from the SRI International incident of January 2, 1992 were subjected to forensic analyses to elucidate potential causes of, or contributing factors to, the explosion. Interrogation of the debris encompassed nuclear, chemical, physical, and materials investigations. Nuclear studies for the determination of tritium and neutron-activation products in stainless steel and brass were conducted. No evidence for signature species indicative of orthodox nuclear events was detected. The inorganic and particulate analyses were likewise negative with respect to residues of unexpected chemical species. Such target compounds included conventional explosives, accelerants, propellants, or any exceptional industrial chemicals. Materials characterization identified the type of stainless steel used in the manufacture of the electrolytic cell as one relatively high in Mo concentration, probably type 316. Metallurgical analyses of the cell vessel wall and its detached base provided no evidence of corrosion or hydrogen embrittlement, leaving only ductile failure of the weld as contributing to the incident. The weld was found to have missed the center-line of the step joint, and the average penetration of the weld was measured to be 54%. The GC-MS analyses of trace organic components in the explosion debris provided a most interesting result. Although no evidence of organic explosives, oxidizers, or other unusual compounds was detected, the presence of an organic oil in the interior of the electrochemical cell was established. It is likely that the source of this oil was lubricating fluid from machining the metal cell components.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Occupational↗
PubMed1986

Reye's syndrome. Salicylate metabolism, viral antibody levels, and other factors in surviving patients and unaffected family members.

To investigate possible etiologic factors for Reye's syndrome (RS), five survivors and their unaffected family members were studied. This study showed low salicylate levels among the patients with RS compared with siblings and parents when challenged with three doses of aspirin. Thus, the patients with RS, three to ten years after having had RS, exhibited normal or increased ability to metabolize aspirin. We found significantly higher antibody levels to influenza A and varicella among the patients with RS, further supporting the importance of these viral infections in the etiology of the syndrome.

Adolescent↗
PubMed1986

The isolation and identification of a new mutagen from fried ground beef: 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP).

A new mutagenic compound has been isolated from ground beef which was fried at 300 degrees C for 5.5 min on each side. The new mutagen was purified using an aqueous acid extraction, XAD-2 adsorption-solvent elution, a series of preparative and analytical h.p.l.c. purification steps, and monitored with the Ames/Salmonella assay. This study reveals a new mutagen member of the amino-imidazoazaarene class of aromatic amines, having a mol. w of 224, and a formula of C13H12N4 as determined by high-resolution mass spectrometry. N.m.r. spectrometry supports the structure, 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP), for the new mutagen. The 1-methyl and 3-methyl synthesized isomers of PhIP were compared to the purified mutagen. The two isomers had identical mass spectra to the purified compound, but only the 1-methyl isomer showed similar u.v. and n.m.r. spectra. The two synthetic isomers were separable by h.p.l.c. and the beef derived component co-eluted with the 1-methyl-PhIP isomer. PhIP has a specific activity in the Ames/Salmonella assay of 1950 revertants/microgram. Although it is not as mutagenic as other compounds isolated from fried beef (e.g. MeIQx, 58 000 revertants/microgram) it is the most abundant mutagenic compound by mass in fried beef. PhIP is present at approximately 15 p.p.b. of the original weight of uncooked beef (accounting for 75% of the mass of genotoxic material) and contributes 18% of the total mutagenicity of the fried beef.

Animals↗
PubMed1986

Identification of the mutagens in cooked beef.

The purification of cooking mutagens depends on the extraordinary sensitivity of the Ames/Salmonella mutagenicity test and its usefulness for tracking the mutagens during the purification steps. Following aqueous/acid (pH 2) extraction of fried ground beef (cooked at 200, 250, or 300 degrees C), XAD-2 column adsorption and elution with acetone, and acidic and basic liquid/liquid extractions, the samples are separated into six distinct peaks with preparative reverse-phase HPLC. A total of nine distinct mutagens can be separated after two additional HPLC steps. These compounds fall into a class of compounds called aminoimidazoazaarenes (AIAs). The majority of the mutagenic activity is made up of MeIQx1 (m/z 213, C11H11N5), DiMeIQx (m/z 227, C12H13N5), trimethylimidazopyridine (TMIP) (m/z 176, C9H12N4) and phenylimidazopyridine (PhIP) (m/z 224, C13H12N4). Smaller contributions are from IQ (m/z 198, C11H10N4), MeIQ (m/z 213, C12H12N4), a nonpolar peak containing oxygen and two unidentified trace polar mutagens. Mass estimates (per kilogram uncooked beef) include: 15 micrograms for PhIP, 1.0 micrograms for MeIQx, 0.5 microgram for DiMeIQx, and 0.02 microgram for IQ. Because of the uncoupling of mutagenic and carcinogenic potencies of these aromatic amines, the PhIP, which contributes the highest mass content to the cooked meat, but has the lowest mutagenic potency, might ultimately make a significant contribution to the carcinogenicity.

Animals↗
PubMed1985

Interspecies variation in ritodrine metabolism.

The metabolism of ritodrine has been studied in the rat, both in vitro and in vivo, and in the in vivo pregnant baboon, with the use of tritium-labeled drug as a probe. Combined enzymatic degradation and radiochromatography of the radioactive components of bile and urine show that ritodrine undergoes significant Phase l metabolism in addition to conjugation to both sulfate and glucuronide, as previously reported. The presence of more than one conjugate is shown, and evidence for major interspecies variation in patterns of metabolism and conjugation is presented, with comments on the applicability of results to human clinical use.

Animals↗
PubMed1985

Metabolism and disposition of ritodrine in a pregnant baboon.

Relatively little is known about the detailed metabolism of ritodrine. The aim of this study was to examine ritodrine metabolism and pharmacokinetics in the maternal and fetal baboon. A fetal-maternal model was made with use of Papio anubis at 144 days of gestation. Tritiated ritodrine was injected as an intravenous bolus into the mother. Maternal and fetal blood samples, amniotic fluid, and maternal urine were collected at time intervals. Samples were analyzed by a combination of high-pressure liquid chromatography and radiochromatography. Conjugated metabolites were recovered and characterized by cleavage studies with use of beta-glucuronidase and sulfatase. The distribution half-life of ritodrine in the mother was 6 minutes and the elimination half-life was 61 minutes. Metabolites were found in both fetal serum and amniotic fluid. The concentrations of ritodrine and its metabolites in fetal serum were at or above the concentrations in maternal serum at 2 hours after maternal intravenous injection. The principal metabolite identified was the sulfate conjugate. The fetus appears to accumulate metabolites. These data indicate that ritodrine crosses the placenta and, in the baboon, achieves levels in the fetus equal to or higher than those in the mother.

Amniotic Fluid↗
PubMed1985

Effects of temperature, patty thickness and fat content on the production of mutagens in fried ground beef.

The high-pressure liquid chromatography (HPLC) profiles of mutagenic components were compared for extracts of ground beef patties fried at 200, 250 and 300 degrees C for 6 min/side. The HPLC profiles of the mutagenic samples were similar, although total mutagenic activity in Salmonella typhimurium TA1538 was roughly four times as high after the 300 degrees C than after the 200 degrees C frying. Six mutagenic peaks were analysed quantitatively at different temperatures and meat thicknesses. Two major components, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-aminotrimethylimidazo[4,5-f]quinoxaline, and a minor component, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), were all present at the three different temperatures. Thus, in general, cooking temperature seems to have a major effect on the quantities of mutagens produced but not on their HPLC profiles. The thickness of the meat patty did not affect the total yield of mutagens except at longer cooking times (8-10 min/side) and, in general, neither did it affect the HPLC profiles of the mutagenic components. Total mutagenic activity increased with increasing cooking times. Increasing the fat content lowered the total mutagenicity, with 150,000 revertants/kg of fresh beef at 30% fat compared with 230,000 revertants/kg at 15%, but had little effect on the mutagenicity due to IQ.

Animals↗
PubMed1983

Identification of long chain dicarboxylic acids in the serum of two patients with Reye's syndrome.

Sera from two patients with Reye's Syndrome were analysed by computerized capillary gas chromatography--mass spectrometry profiling techniques. The most striking abnormalities were the accumulation of long chain dicarboxylic acids. Four saturated dicarboxylic acids (dodecanedioic, tetradecanedioic, hexadecanedioic, and octadecanedioic), and six unsaturated long chain dicarboxylic acids (dodecenedioic, tetradecenedioic, tetradecadienedioic, hexadecenedioic, octadecadienedioic, and octadecenedioic) were identified. The C16 and C13 dicarboxylic acids have never been reported for Reye's Syndrome or any other dicarboxylic acidemias. The data might reflect marked increase of extramitochondrial omega-oxidation of long chain fatty acids or impaired metabolism of omega-dicarboxylic acids formed in Reye's patients.

Child↗
PubMed1983

Oxygen fixation into hydroxyproline in etiolated maize seedlings : verification by tandem mass spectrometry.

Etiolated maize (Zea mays L.) seedlings were grown in the dark for 5 days in an atmosphere enriched with 10.0 atom% (18)O(2). Hydroxyproline was isolated from root and shoot tissues, purified, and methylated. It was not possible to determine (18)O incorporation into hydroxyproline by conventional mass spectrometry because the final product was not sufficiently pure. The final product was analyzed successfully by tandem mass spectrometry. The (18)O content of the hydroxyl oxygen atom was 10 +/- 0.7 atom%. This result demonstrates that the hydroxyl oxygen atom in hydroxyproline was derived exclusively from molecular oxygen.

Journal Article↗
PubMed1983

Identification and characterization of the glucuronide metabolite of diethyldithiocarbamic acid in the bile from the isolated perfused rat liver by gas chromatography and mass spectrometry.

The glucuronide metabolite of diethyldithiocarbamic acid has been identified in bile from the isolated perfused rat liver. The bile was chromatographed on XAD-2 resin, pertrimethylsilylated with BSTAF + 1% TMCS, identified and characterized by combined gas chromatography and mass spectrometry. The glucuronide characterized as the silylated derivative showed no molecular ion but a small fragment ion at M-15(598).

Animals↗
PubMed1982

Capillary gas chromatographic-mass spectrometric profiles of trimethylsilyl derivatives of organic acids from amniotic fluids of different gestational age.

Amniotic fluid from different gestational age patients was partitioned into neutral, acidic and basic fractions. The organic acids were trimethylsilylated and analyzed by glass capillary gas chromatography-mass spectrometry. A marked difference in the level of hippuric acid was observed between samples from early (15-22 weeks) and late (30-38.5 weeks) pregnancy. This difference probably reflects the degree of maturity in the fetal liver and kidney. The procedures establish amniotic fluid profiles of substances of varying gestational age and should be useful in determining alterations caused by diseases.

Amniotic Fluid↗