Biomedical subjects

W Lee Hearn

Publications and source records attributed to W Lee Hearn.

4 recordsLinked to original sources

PubMed2003

Stability of ethanol in postmortem blood and vitreous humor in long-term refrigerated storage.

Ethanol concentrations in postmortem blood and vitreous humor samples collected at the Miami-Dade Medical Examiner Department over 5-6 years ago were reexamined to assess whether vitreous humor is a more reliable specimen for the analysis of ethanol in samples stored long term. The average change in 50-mL polypropylene tubes containing blood was 0.06 gm/dL (35% loss). On the other hand, vitreous humor samples collected in 10-mL gray-top Vacutainer tubes yielded an average change of 0.01 gm/dL (6.1% loss). This study demonstrates that vitreous humor may be a reliable matrix for ethanol analysis following prolonged refrigerated storage of the samples.

Chromatography, Gas↗

PubMed2003

Fatal cold medication intoxication in an infant.

The case history and toxicological findings of an infant fatality involving pseudoephedrine, brompheniramine, and dextromethorphan are presented. Concentrations of brompheniramine and dextromethorphan were measured in both postmortem blood and liver specimens using a gas chromatograph equipped with a nitrogen-phosphorus detector. Brompheniramine and dextromethorphan were 0.40 mg/L and 0.50 mg/L, respectively, in the blood sample and 0.16 mg/kg and 0.57 mg/kg in the liver sample. The concentration of pseudoephedrine in blood and liver specimens was measured using gas chromatography-mass spectrometry and was determined to be 14.4 mg/L in the blood and 16 mg/kg in the liver. Additionally, a baby bottle allegedly administered to the infant was collected as evidence and sent to the Medical Examiner's Office for evaluation. The amounts of total brompheniramine, dextromethorphan, and pseudoephedrine remaining in the baby bottle were 1.4 mg, 9.4 mg, and 40 mg, respectively.

Brompheniramine↗

PubMed2002

Dopamine transport function is elevated in cocaine users.

Dopaminergic transmission has been suggested to be a primary mechanism mediating reinforcement, withdrawal and craving associated with psychostimulant addiction. Pyscho-stimulants attenuate dopamine transporter (DAT) clearance efficiency, resulting in a net increase in synaptic dopamine levels. Re-uptake rate is determined by the number of functional DAT molecules at the membrane surface. Previous in vivo imaging studies in humans and in vitro studies in post-mortem human brain have demonstrated that chronic cocaine abuse results in a neuroadaptive increase in DAT-binding site density in the limbic striatum. Whether this increase in DAT availability represents an increase in the functional activity of the transporter is unknown. Here, we present evidence that DAT function is elevated by chronic cocaine abuse. The effect of increasing post-mortem interval on the functional viability of synaptosomes was modeled in the baboon brain. Baboon brains sampled under conditions similar to human brain autopsies yielded synaptosomal preparations that were viable up to 24 h post-mortem. Dopamine (DA) uptake was elevated twofold in the ventral striatum from cocaine users as compared to age-matched drug-free control subjects. The levels of [3H]DA uptake were not elevated in victims of excited cocaine delirium, who experienced paranoia and marked agitation prior to death. In keeping with the increase in DAT function, [3H]WIN 35,428 binding was increased in the cocaine users, but not in the victims of excited delirium. These results demonstrate that DA uptake function assayed in cryopreserved human brain synaptosomes is a suitable approach for testing hypotheses of the mechanisms underlying human brain disorders and for studying the actions of addictive drugs in man.

Adult↗

PubMedDate not supplied

Fatality due to acute alpha-methyltryptamine intoxication.

In February 2003, the Miami-Dade County Medical Examiner Department reported the first known death in the country related to alpha-methyltryptamine (AMT). AMT is an indole analogue of amphetamine investigated in the 1960s as an antidepressant, stimulant, and monoamine oxidase inhibitor. Today, AMT is recognized as a powerful psychedelic drug among high school and college-aged men and women. Its popularity is partly due to the multitude of anecdotal websites discussing AMT as well as its legality and availability for purchase via the Internet prior to April 2003. Emergency designation of AMT as a Schedule 1 controlled substance by the Drug Enforcement Administration occurred shortly after the death in Miami-Dade County. The case in Miami involved a young college student who, prior to death, advised his roommate that he was "taking hallucinating drugs" and as a result had "discovered the secret of the universe". Approximately 12 h later, the roommate discovered the deceased lying in bed unresponsive. An empty 1-g vial of AMT was recovered from the scene and sent to the toxicology laboratory. Initial screening of urine by enzyme-multiplied immunoassay technique was positive for amphetamines, and the basic drug blood screen detected a small peak later identified by mass spectrometry as AMT. For quantitation, AMT was isolated using solid-phase extraction, derivatized with pentafluoropropionic anhydride, and analyzed using gas chromatography-mass spectrometry. Quantitative analysis was based upon m/z 276, 303, and 466 for AMT and m/z 306, 333, and 496 for the internal standard, 5-methoxy-alpha-methyltryptamine. A linear calibration curve from 50 to 500 ng/mL was used to calculate the concentration of AMT in the samples and controls. Blood, tissue, and gastric specimens were diluted to bring the observed concentration within the limits of the standard curve. Matrix matched controls were extracted and analyzed with each run. Postmortem iliac vein blood revealed 2.0 mg/L, gastric contents (48 g collected at autopsy) contained 9.6 mg total of AMT, liver contained 24.7 mg/kg, and the brain contained 7.8 mg/kg. An additional Medical Examiner case from another jurisdiction revealed 1.5 mg/L in antemortem serum.

Adult↗