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At least 19 recordsLinked to original sources
PubMed1975

Postmortem changes in brain catecholamine enzymes.

Postmortem changes in the activities of tyrosine hydroxylase, dopa decarboxylase, and dopamine-beta-hydroxylase were examined in various areas of rat brain. Tyrosine hydroxylase activity decreased in an exponential fashion with a half-time of two to four hours in caudate-putamen, substantia nigra, and locus ceruleus. Dopa decarboxylase activity remained within 20% of control values at five hours in these areas, but then decreased precipitously. Dopamine-beta-hydroxylase activity remained within 20% of control for at least 20 hours after death.

Animals↗
PubMed1992

Postmortem changes of triazolam concentrations in body tissues.

Postmortem changes of triazolam concentrations in body tissues were examined using rats, in order to find the most suitable tissue samples for toxicological analysis. Triazolam was orally given to rats (5 mg/kg), and then the rats were sacrificed 1 hour after administration. Tissue samples were collected 0, 1 and 2 days after storage at 22-24 degrees C, and the triazolam concentration in each sample was measured using gas chromatography with a nitrogen phosphorus detector. Triazolam concentrations were markedly increased in the spleen, the abdominal muscle, the liver and the kidney, and were slightly increased in the blood and the lung. On the other hand, no changes were observed in the thigh muscle or the brain, and the value in the thigh muscle was similar to those in the blood samples collected immediately after death. The results indicate that triazolam diffuses into the surrounding tissues through the stomach wall after death, so that the thigh muscle and the brain have to be analyzed as well as the blood for a correct diagnosis of triazolam ingestion.

Administration, Oral↗
PubMed1992

Postmortem changes in electrical resistance of the gastric wall during the early postmortem period in rats.

A simple and reliable technique was employed for measurement of (dc) electrical resistance of the gastric wall of rats. Tissue resistance decreased linearly (r = -0.87; P less than 0.001) from 66.1 +/- 12.1 kOhm/cm2 immediately following death to 23.3 +/- 3.5 kOhm/cm2 at a postmortem interval of 24 h. These changes are believed to reflect progressive postmortem changes in the physical dimensions of the intercellular space and/or changes in electrical conductivity of the intercellular/extracellular fluids.

Animals↗
PubMed1992

Postmortem changes and pharmacokinetics: review of the literature and case report.

OBJECTIVE: To review the mechanisms and sequence of events that occur during ischemia and cell death and following death of the human body. The impact of these postmortem events on the distribution and pharmacokinetic behavior of drugs is described. The case study presented illustrates a possible situation where such postmortem changes could have affected the pharmacokinetics of procainamide. DATA SOURCES: English-language journal articles and reference texts identified from pertinent data sources. DATA SYNTHESIS: Postmortem changes in the human body begin at the cellular level with the onset of ischemia. As the length of time of ischemia increases and death ensues, more changes occur and lead to deterioration in tissue and organ function. These changes may affect the pharmacokinetic and distribution behavior of certain drugs. Drugs particularly affected are those whose distribution is dependent on molecular size, lipophilicity, pH, energy-dependent transport, and tissue binding. Such drugs include the tricyclic antidepressants, digoxin, and cimetidine. Other drugs with similar characteristics, such as procainamide, may also demonstrate like changes in distribution and pharmacokinetics. CONCLUSIONS: When measuring drug concentrations after death, it is important to consider the phenomenon of postmortem redistribution. Postmortem drug concentrations may not be a true reflection of antemortem concentrations and as a result, wrong conclusions could be made about the cause of death. More studies characterizing the postmortem distribution and pharmacokinetic characteristics of specific drugs are necessary.

Antidepressive Agents, Tricyclic↗
PubMed1977

[Postmortem changes in skin color].

By the employment of the colorimetric method statistically significant objective data on postmortem changes in the colour of different parts of the skin have first been obtained. Histological and spectrophotometric studies were carried out in order to elucidate the causes of these changes. The colour of the cadavar skin as well as the colour of the human skin in life depends on primary pigments: hemoglobin, melanin, carotene and melanoid. A certain role is likely to be played by the main structural proteins of the derma and epidermis: collagen and keratin. The cadavar skin colour differs in variations of the dominant wave length and reflectance which are associated with postmortem redistribution of the blood under the effect of the gravity and qualitative transformation of oxyhaemoglobin into reduced haemoglobin. The distribution of melanin, carotene, and melanoid does not differ from that in life. The most specific index of the amount of melanin is the purity of colour and not reflectance.

Adult↗
PubMed1976

[Postmortem changes in the endothelial contour of the surface of large human arteries].

Changes in the relief of the endothelial surface of the common carotid artery common iliac artery in man in the postmortem period were studied by the method of scanning electron microscopy. It is established that the normal relief of the inner surface of the vessels could be studied only during the first few hours after death. Rapidly developing postmortem changes lead to drastic distortion of the stratified endothelial surface and to desquamation of the endothelial lining. On the 2nd and 3rd day of the postmortem period the relief of the inner surface of the vessel is determined by the elements which are incorporated into the composition of the subendothelial layer of the intima.

Carotid Arteries↗
PubMed1991

Site-dependent postmortem changes in blood cocaine concentrations.

When a forensic toxicologist interprets postmortem blood cocaine findings he usually must make assumptions regarding perimortem drug concentrations. In-vitro studies have shown that cocaine rapidly hydrolyzes in unpreserved blood, particularly at elevated temperatures. However, other studies have demonstrated site-dependent postmortem release of some drugs from tissue stores accompanied by increases in drug concentrations in the blood. This study was undertaken to investigate whether blood cocaine concentrations change in the body during the postmortem interval and, if so, to measure the direction and magnitude of the changes. In medical examiner cases in which scene investigation suggested that the decreased was a cocaine user, blood samples were collected as soon after death as possible. At autopsy, a second set of samples was collected. Analysis of paired samples by gas chromatography/mass spectrometry (GC/MS) revealed dramatic differences in the cocaine concentration. The magnitude and direction of the change appears to be site dependent. Usually, but not invariably, cocaine concentration in subclavian vein blood decreases while that in heart, aorta, and femoral vein blood increases during the interval between death and autopsy. The findings emphasize the danger inherent in attempting to estimate the concentration of cocaine in blood at the time of death from postmortem data.

Adolescent↗
PubMed1977

Postmortem changes in stereological parameters of cerebral capillaries.

The present study investigated the influence of different postmortem times on stereological parameters of capillaries in the cerebral cortex. For the human investigation different brain regions of two 77 and 79 year-old subjects were examined. The animal experiment, carried out on 10 male cats, allowed a comparison between intravitam deep-frozen cerebral cortex and tissue obtained after decapitation. The parameters were diameter Di, volume fraction VVi, surface-to-volume ratio Si/Vi, mean minimal distance between capillary centers of gravity deltaAB, length per unit cortex volume LVi, and number of fragments per measuring field Ni, AT. Neither the cat experiment nor the human investigation yielded a noteworthy change of the capillary diameter in the postmortem cortical tissue. Nevertheless, a significantly enlarged mean minimal distance between capillaries in the cat cerebral cortex shortly after decapitation (30 sec) suggests the formation of edema which then regresses. Furthermore the experiment revealed that 22 hours after death there is a significantly (p less than 0.01) diminished volume fraction and length per unit cortex volume with an augmented surface-to-volume ratio. These changes are thought to be a consequence of water loss. In contrast to the animal experiment the human cerebral capillaries showed no changes in stereological parameters at two different postmortem times. These results encourage continuation of further stereological investigations on human brains obtained at autopsy and may contribute to the understanding of the aging process in the human cerebral cortex.

Aged↗