PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Postmortem Changes”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources
PubMed1980

[Possibility of determination of the type of cardiomyocyte death with the aid of ultrastructural analysis].

An attempt was made to determine the ultrastructure of those types of cell death which may occur experimentally only during life and to compare them with the findings obtained from the autopsy materials of the myocardium of persons dying suddenly or from acute myocardial infarction. Three ultrastructural types of cellular death were determined in the experimental and autopsy material: primary-ischemic, primary-calcium, and secondary-calcium types. The ultrastructural pattern of some irreversible changes found in the autopsy material may be used for retrospective judgement on the mechanisms of cell death. The results obtained do not completely solve the problem of interpretation of ultrastructural findings in examinations of human postmortem materials although open some approaches for using electron microscopy in addition to the main sources of information in the study of sudden death.

Acute Disease↗
PubMed2004

Extracellular matrix changes in stented human coronary arteries.

BACKGROUND: Restenosis after stenting occurs secondary to the accumulation of smooth muscle cells (SMCs) and extracellular matrix (ECM), with the ECM accounting for >50% of the neointimal volume. The composition of the in-stent ECM has not been well characterized in humans. METHODS AND RESULTS: Postmortem human coronary arteries (n=45) containing stents underwent histological assessment of neointimal proteoglycans, hyaluronan, collagen (types I and III), SMCs, and CD44 (a cell surface receptor for hyaluronan). The mean duration of stent implantation was 18.7 months; stents in place > or =3 to <9 months (n=17) were assigned to group 1, stents > or =9 to <18 months old (n=19) to group 2, and stents > or =18 months old (n=9) to group 3. In groups 1 and 2, neointimal versican and hyaluronan staining was strongly positive, colocalized with alpha-actin-positive SMCs, and was greater in intensity compared with group 3. Conversely, decorin staining was greatest in group 3. The neointima of both group 1 and 2 stents was rich in type III collagen, with reduced staining in group 3. Type I collagen staining was weakest in group 1 stents, with progressively stronger staining in groups 2 and 3. SMC density and stent stenosis were significantly reduced in group 3 stents compared with groups 1 and 2. CD44 staining colocalized with macrophages and was associated with increased neointimal thickness. CONCLUSIONS: The ECM within human coronary stents resembles a wound that is not fully healed until 18 months after deployment, followed by neointimal retraction. ECM contraction may be a target for therapies aimed at stent restenosis prevention.

Aged↗
PubMed1975

Postmorten changes in the chemistry and histology of normal and edematous brains.

The brains of 18 patients were examined post mortem for histologic criteria of edema, and samples of white and gray matter were analyzed for water, sodium, and potassium content. In a parallel experimental study, brains of cats with unilateral freezing lesions and resulting cerebral edema were similarly examined immediately after death and up to 18 hours post mortem. In both types of material, in gray matter there was a relatively rapid (within less than 4 hours) increase in water and sodium content and fall in potassium content. In normal and edematous white matter, little change was observed post mortem. No correlation could be demonstrated in any of the material studied between water content and histologic grading for cerebral edema. It is concluded that determination of water content in the white matter postmortem could be a useful tool for the neuropathologist. Histologic assessment of cerebral edema is of little value.

Adult↗
PubMed1989

Alterations in adrenergic receptors of frontal cortex and cerebral microvessels in Alzheimer's disease and aging.

Biochemical and pathological abnormalities are evident in the noradrenergic innervation of the cerebral cortex in Alzheimer's Disease (AD), and there is also a decline in aging, which may lead to changes in adrenergic receptors. To assess this question, we analyzed adrenergic receptor subtypes by ligand binding methods in prefrontal cortex and brain microvessels from subjects with AD and aging controls. Ligand binding to adrenoceptors and their subtypes did not change with postmortem delay in obtaining tissues. alpha 1-adrenergic receptors of the frontal cortex did not correlate with age but there was a small (approximately 25%), though significant, reduction in AD subjects. In cerebral microvessels, there were no changes in these receptors. alpha 2-receptors of the cortex significantly declined with age in controls and were also significantly reduced by approximately 50% in AD subjects. However, in cerebral microvessels alpha 2-adrenergic receptors were significantly increased by approximately 60% in AD. We suggest that presynaptic alpha 2-adrenoceptors on noradrenergic synapses may be those that are selectively decreased in the prefrontal cortex in AD. Total beta-receptors in cortex did not correlate with age, nor were they altered in AD. However, beta 1-receptors were decreased but beta 2-receptors were significantly increased in AD, indicating a change in the relative ratio of beta 1/beta 2-receptors. Similarly, beta 2-receptors of cerebral microvessels were significantly increased in AD. These changes suggest receptor "up-regulation" in response to noradrenergic denervation in AD and may reflect functional changes at the blood-brain barrier.

Adult↗
PubMed1994

Effect of delay in cryofixation on the elemental composition of biopsies and post mortem specimens of the thyroid gland.

The time between the excision and cryofixation of a biopsy is most important regarding its elemental composition as demonstrated by an investigation of the thyroid glands of rats and pigs. Biopsies taken and cryofixed immediately served as control specimens. Biopsies that were allowed to stand at room temperature for 20 min before cryofixation and specimens cryofixed at 1 h post mortem were also investigated. Significant changes in the ion concentration of the cells and colloid were apparent in biopsies in which cryofixation was delayed for 20 min and in thyroids cryofixed 1 h post mortem. It was demonstrated that redistribution of electrolytes occurs within 1h post mortem and that similar changes occur in biopsies allowed to stand for 20 min at room temperature before cryofixation. The results stress the importance of immediate cryofixation after surgical excision of a biopsy. This is especially important since numerous elemental changes due to delayed cryofixation resemble those which occur in pathological processes.

Animals↗
PubMed1975

Postmorten glycolysis in ground skeletal muscle as influenced by prerigor freezing and subsequent thawing.

Ground bovine longissimus and rabbit white muscles were frozen (-25 degrees C) in the prerigor state and subsequently thawed(+20 degrees C) to determine the combined effect of grinding and freezing on glycolytic metabolites and enzymes. Frozen ground muscle, when compared to unfrozen ground tissue, showed significantly lower hexose monophosphates and significantly greater levels of all metabolites from fructose diphosphate to phosphoenolpyruvate, indicating activation of phosphofructokinase and inhibition of pyruvate kinase during the freezing process. Thawing caused rapid glycolysis and the metabolites returned to near unfrozen levels by the time glycolysis ceased, due to strong activation of phosphorylase by Ca2+. Both muscle types had a similar pattern of changes.

Animals↗
PubMed1999

A preliminary study of changes in scalp impedance during the early post-mortem period in rats.

An accurate and reproducible technique was used for estimation of scalp impedance (1 kHz) in each of eight rat cadavers, maintained at 9.0 +/- 0.7 degrees C, during the 1 to 144 hour post-mortem period. Scalp impedance increased non-linearly, and in a bimodal manner, between 24 and 144 hours post-mortem. The relationship between scalp impedance and post-mortem interval, and the degree of individual variation in the time course of impedance change, were such that scalp impedance is unlikely to be a suitable tool for estimation of time since death.

Animals↗
PubMed1999

Delimitation of the time of death by immunohistochemical detection of insulin in pancreatic beta-cells.

To improve the possibilities to delimitate the time of death after longer laytime, it was examined if this is possible by immunohistochemical insulin detection. The results show that in our examination material, the pancreatic beta-cells of up to 12-day-old corpses produce a positive immunoreaction towards insulin in all cases, whereas none of the corpses older than 30 days show such a reaction. This means that in case of a negative immunoreaction, the time of death can be assumed to lie more than 12 days before the autopsy. The fact that a negative immunoreaction occurs consistently after 30 days leads to the conclusion that when insulin has been stained in a specimen, the death of the respective person must lie a maximum of 29 days earlier, whereby these time-limits may change in considerably different surrounding conditions.

Autolysis↗
PubMedDate not supplied

[Tattoo pigment in regional lymph nodes--an identifying marker?].

31 of 275 unselected forensic autopsy cases revealed tattoos on one or both sides of the upper extremities, which were nearly always accompanied by pigmentations of the axillary lymph nodes. The deposits of tattoo pigment could already be identified with the naked eye. Their composition reflected the colour ingredients of the tattooed skin. So this easily practicable preparation and examination of the draining lymph nodes makes it possible to establish the identity of unknown corpses by drawing conclusions about former tattoos even if they have been removed or if, owing to postmortal changes of the skin, they cannot be recognized by the forensic pathologist.

Adult↗
PubMed1980

[The electrical resistance and impedance of mammalian muscles during the first days after slaughtering. II: femoral biceps of swine].

The Authors continuing a program of research on the characterization of physical properties of muscular tissues of Mammalia after slaughtering, have performed a new series of observations on the electrical conductance of femoral biceps of swine. Using two groups of specimen (one cut along the axis of the muscular fibers, the other at right angle of them), the AA. checked different values of resistance and of impedance, particularly during the first hours. On the contrary in the final stage of the research the data are quite similar in both the groups of samples. In the comment has taken into account the hypothesis that, on the basis of changes in the tissue structures, electrochemical processes could explain the results.

Animals↗
PubMed2004

Systematic changes in gene expression in postmortem human brains associated with tissue pH and terminal medical conditions.

Studies of gene expression abnormalities in psychiatric or neurological disorders often involve the use of postmortem brain tissue. Compared with single-cell organisms or clonal cell lines, the biological environment and medical history of human subjects cannot be controlled, and are often difficult to document fully. The chance of finding significant and replicable changes depends on the nature and magnitude of the observed variations among the studied subjects. During an analysis of gene expression changes in mood disorders, we observed a remarkable degree of natural variation among 120 samples, which represented three brain regions in 40 subjects. Most of such diversity can be accounted for by two distinct expression patterns, which in turn are strongly correlated with tissue pH. Individuals who suffered prolonged agonal states, such as with respiratory arrest, multi-organ failure or coma, tended to have lower pH in the brain; whereas those who experienced brief deaths, associated with accidents, cardiac events or asphyxia, generally had normal pH. The lower pH samples exhibited a systematic decrease in expression of genes involved in energy metabolism and proteolytic activities, and a consistent increase of genes encoding stress-response proteins and transcription factors. This functional specificity of changed genes suggests that the difference is not merely due to random RNA degradation in low pH samples; rather it reflects a broad and actively coordinated biological response in living cells. These findings shed light on critical molecular mechanisms that are engaged during different forms of terminal stress, and may suggest clinical targets of protection or restoration.

Adult↗
PubMed1999

Controlled atmosphere stunning of poultry.

For more than 20 yr Stork PMT has carried out a lot of research into stunning and killing of poultry with electrical and mechanical methods and by applying gas mixtures. For the past 3 yr, research was carried out under the European umbrellas (AIR and EUREKA) together with BOC, The Spelderholt, CIVO, and Bristol University. This research program involved tests on broiler stunning or killing with various gas mixtures. The effect on meat quality, bleeding, and plucking was studied, as well as the use of gas as a humane way of killing broilers. The study of meat quality was based on tenderness tests conducted on the shear force principle, meat color, and drip and cooking losses. The percentage of blood loss in bleeding, blood spots, and the amount of blood in the veins in relation to the gas mixtures and time of hanging were measured. The effect of gas killing on the plucking characteristics was studied by determining the feather release force and product handling. The behavior of the birds, reflexes, the onset of convulsions, electroencephalograms, and evoked responses were studied in relation to the humanness of gas killing. Anoxia generated through argon or a mixture of argon and carbon dioxide or hypercapnic hypoxia seems to be very promising. The tests revealed that meat tenderness and drip losses will improve. The blood spots, especially those on the thighs and breasts caused by stunning and hanging, disappear altogether. It also appeared that animal welfare will be drastically improved. From a technological point of view, broiler killing in a controlled gas atmosphere is considered to be the optimal process. However, successful introduction of the process requires legislative changes and poultry processors must be made aware of its economic benefits.

Abattoirs↗
PubMed1991

[Significance of intraosseous skull cap hematoma for reconstruction of skull injuries].

Diaphanoscopic postmortal examination of blunt impact injuries to the head sometimes revealed non-diaphanous regions deriving from intraossary haematomata. Precise delimitation of these haematomata in the diploe from haematopoietic foci or neoplastic lesions was possible by means of histological examination. The location of the intraossary skull-cap haematomata coincided with corresponding injuries of the scalp as contusions and lacerations; they were often accompanied by fissural bone lesions and linear fractures. As such a diploetic haemorrhage represents a facultative counterpart of scalp contusion, its demonstration allows conclusions to be drawn as to the area of the impact, even if, owing to postmortal changes, the scalp is no longer assessable.

Adult↗