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At least 433 records · Page 24Linked to original sources
PubMed2003

Changes of GABA receptors and dopamine turnover in the postmortem brains of parkinsonians with levodopa-induced motor complications.

Brain samples from 14 Parkinson's disease patients, 10 of whom developed motor complications (dyskinesias and/or wearing-off) on dopaminomimetic therapy, and 11 controls were analyzed. Striatal 3beta-(4-(125)I-iodophenyl)tropane-2beta-carboxylic acid isopropyl ester ([(125)I]RTI-121) -specific binding to dopamine transporter and concentration of dopamine were markedly decreased, but no association between level of denervation and development of motor complications was observed. The homovanillic acid/dopamine ratio of concentrations was higher in putamen of patients with wearing-off compared to those without. Striatal (35)S-labeled t-butylbicyclophosphorothionate ([(35)S]TBPS) and [(3)H]flunitrazepam binding to GABA(A) receptors were unchanged in patients with Parkinson's disease, whereas [(125)I]CGP 64213 -specific binding to GABA(B) receptors was decreased in the putamen and external segment of the globus pallidus of parkinsonian patients compared with controls. [(3)H]Flunitrazepam binding was increased in the putamen of patients with wearing-off compared to those without. [(35)S]TBPS-specific binding was increased in the ventral internal globus pallidus of dyskinetic subjects. These data suggest altered dopamine metabolism and increased GABA(A) receptors in the putamen related to the pathophysiology of wearing-off. The present results also suggest that an up-regulation of GABA(A) receptors in the internal globus pallidus is linked to the pathogenesis of levodopa-induced dyskinesias.

Aged↗
PubMed2001

[A study on the relationship between postmortem interval and the changes of DNA content in the kidney cellule of rat].

OBJECTIVE: To study changes of DNA content in the kidney cellule of rats and relationship with the postmortem interval. METHODS: This experiment chose seven parameter of cell nuclear, including the area and integral optical density, determined the changes of DNA content in the kidney cellule of 15 rats at different intervals between 0 and 48 h postmortem with auto-TV-image system. RESULTS: The degradation rate of DNA in nuclear has a certainty relationship to early PMI(in 48 h) of rat, and get binomial regress equation. CONCLUSION: Determining the quantity of DNA in nuclear should be an objective and exact way to estimate the PMI.

Animals↗
PubMed2001

Topographical and quantitative post mortem assessment of the rat skin mast cells.

Rat skin mast cell (MC) number and density change due to the postmortem storage of the material at 6-8 degrees C during a 19-day period. Both the number and the density of the MC in the 200 microm thick subepidermal layer decreased with the square of the time (p > or = 0.99). The count and the density may be used interchangeably in topographic studies of the rat MC.

Animals↗
PubMed1990

Postmortem viability and early changes in organ culture of human and rabbit aortic endothelial cells.

In order to understand the role of the postmortem interval (PMI) on endothelial cell changes both in human and rabbit aortas, we have examined the ultrastructural cytomorphologic alterations of these cells. Human aorta (HA) and rabbit aorta (RA) were maintained in calcium-free, glucose-supplemented Hank's balanced salt solution (HBSS). Rabbit endothelial cells (REC) on the aorta (organ culture) assayed morphologically survive for at least 12 h in culture solution. The predominant morphological change in the RA was the formation of multiple subendothelial vacuoles (SEV). These vacuoles may form as the results of increased permeability of endothelial cells to ions and fluid or cell contraction. Cell to cell connection remained intact. Individual and dispersed endothelial cells were observed 8 h after removal from the animal when incubated in calcium-free HBSS. These necrotic endothelial cells were scattered among viable endothelial cells. Human aortic endothelial cells were also well preserved in the same media for periods of 6-8 h postmortem. Increased extracellular calcium (1.3 mM) in the incubation media caused accelerated cell death. These findings suggest that aortic endothelial cells can be preserved for longer periods of postmortem time than would be expected and that the use of calcium-free HBSS media supplemented with glucose improves endothelial cell viability in vitro.

Adult↗
PubMed2006

[To estimate early postmortem interval by investigating changes of rats' gastrocnemius excitability].

OBJECTIVE: To investigate the changes of excitability of rats' gastrocnemius after rats were died from mechanic asphyxia, so as to make an objective evidence for estimating of the early postmortem interval. METHODS: After rats were sacrificed by mechanic asphyxia, the reaction of rats' gastrocnemius to variable electric stimulation at different period after death were recorded by electricphysiological method. RESULTS: Changes in the properties of excitable tissue to electric stimulate in rats' gastrocnemius after mechanic asphyxia seems to be well correlated with the early postmortem interval and appeared a linear relation in certain period. CONCLUSION: The regular changes of excitability in muscle might be a useful means for estimating of early postmortem interval.

Action Potentials↗
PubMed1998

Changes in the calpains and calpastatin during postmortem storage of bovine muscle.

Changes in activity and protein status of micro-calpain, m-calpain, and calpastatin in bovine semimembranosus muscle during the first 7d of postmortem storage were monitored by using assays of proteolytic activity, SDS-polyacrylamide gel electrophoresis, and Western blot analysis. Extractable m-calpain activity changed slightly during the first 7d after death (decreased to 63% of at-death activity after 7d), whereas extractable calpastatin activity decreased substantially (to 60% of at-death activity after 1d and to 30% of at-death activity after 7d of postmortem storage) during this period. Extractable micro-calpain activity also decreased rapidly (to 20% of at-death activity at 1d and to less than 4% of its at-death activity at 7d after death) during postmortem storage. Western blot analysis showed that the 80-kDa subunit of m-calpain remained undegraded during the first 7d after death but that the 125- to 130-kDa calpastatin polypeptide was gone entirely at 7d after death. Hence, the calpastatin activity remaining at 7d originates from calpastatin polypeptides that are 42 kDa or smaller. The 80-kDa micro-calpain subunit was almost entirely in the 76-kDa autolyzed form at 7d after death; this form is proteolytically active in in vitro systems, and it is unclear why the postmortem, autolyzed micro-calpain is not active. Over 50% of total muscle micro-calpain is tightly bound to myofibrils 7d after death; this micro-calpain is also nearly inactive proteolytically. Unless postmortem muscle contains some factor that enables micro-calpain in this muscle to be proteolytically active, it is not clear whether micro-calpain could be responsible for any appreciable postmortem myofibrillar proteolysis.

Animals↗
PubMed2002

Dietary-induced changes of muscle growth rate in pigs: effects on in vivo and postmortem muscle proteolysis and meat quality.

The effects of various growth rates in pigs induced by four different feeding strategies on the activity of the calpain system and on postmortem (PM) muscle proteolysis and tenderness development were studied. An increased growth rate may be caused by an increased protein turnover, which results in up-regulated levels of proteolytic enzymes in vivo that, in turn, possibly will affect PM tenderness development. It can be hypothesized that increased proteolytic activity pre-slaughter will increase the PM tenderization rate. From postnatal d 28 to d 90 (phase 1) the pigs were divided into two groups, given either ad libitum (A) or restricted (R, 60% of ad libitum) access to feed. The two groups were then divided into two subgroups, given either restricted or ad libitum access to feed from d 91 to slaughter at d 165 (phase 2). Measurements of the activity of mu-calpain, m-calpain, and calpastatin; concentrations of total collagen and the percent of soluble collagen; and RNA, DNA, and elongation factor-2 where made at slaugther. Myofibrillar fragmentation index (MFI) was determined at slaughter and 24 h PM. Warner-Braztler shear force was determined 1 d and 4 d PM. Pigs fed restricted diets in phase 1 and fed ad libitum in phase 2 (RA pigs) had increased growth rates in the last phase compared to pigs fed ad libitum during both phase 1 and phase 2 (AA pigs). The increased growth rate (compensatory growth) was followed by an increased proteolytic potential (mu-calpain:calpastatin ratio), increased MFI values, and higher tenderization rates. There was a positive correlation between the activities of m-calpain and growth rates (r = 0.35, P = 0.03), and between RNA levels and growth rates (r = 0.43, P = 0.006). The proposed hypothesis is largely supported by the results. The activities of both mu- and m-calpain at slaughter were highest in fast-growing pigs. The calpain activity was highest in RA pigs, which in turn also had the fastest growth rates prior tslaughter among the four groups. This implies that the synthesis of these enzymes was up-regulated during the second feeding period to a larger extent in RA pigs. The proteolytic potential and the MFI values indicate that the up-regulated in vivo calpain activity had an effect on PM protein degradation, which also is supported by the higher tenderization rate in RA pigs.

Animal Feed↗
PubMed2004

Ultrastructural changes during in situ early postmortem autolysis in kidney, pancreas, liver, heart and skeletal muscle of rats.

Many morphological studies of the postmortem interval were carried out under conditions in which the tissue was incubated in vitro after extirpation. However, the extirpation affects cell viability. We examined the ultrastructural changes in the kidney, pancreas, liver, heart and skeletal muscle of male Wistar rats occurring postmortem in situ. In each organ, cell edema (cell swelling), appearance of amorphous dense deposits in the mitochondria, loss of glycogen granules, dilation of the endoplasmic reticulum, clumping and margination of nuclear chromatin, and/or condensation of nuclear chromatin were observed, but the duration of the period of ultrastructural change was organ specific. Most of the ultrastructural changes occurred earlier in kidney. In hepatocytes, the morphological degeneration occurred later than in the renal tubule epithelium and earlier than that in the myocardium. Of the five organs we examined, skeletal muscle showed the greatest delay in postmortem change. In the distal tubule epithelium and pancreatic acinar cells, two forms of nuclear change were seen: one resembled necrotic change and the other resembled apoptotic change. The effect of lysosomes and hydrolytic enzymes was not as great as previous findings.

Animals↗
PubMed2003

Double logarithmic, linear relationship between plasma chloride concentration and time since death in humans in Chandigarh Zone of North-West India.

Estimation of time since death with the change in chloride concentration in postmortem blood is the topic of discussion in the study. Querido (Forensic Sci Int 45 (1990) 117) had demonstrated a highly significant double logarithmic linear relationship between the plasma chloride concentration and postmortem interval in Wistar rats. Henceforth, the present study was carried out to substantiate this propensity in humans. Chloride concentration in postmortem blood of 474 subjects revealed a highly significant relationship between logarithm of plasma chloride concentration and logarithm of the time since death during 3-58 h of death. Notwithstanding, time since death can be predicted from plasma chloride concentration with standard error of estimate of 2.1 h but factors like environmental temperature, cause of death, age and gender influences it significantly.

Adolescent↗
PubMed1994

Time-dependent changes in electrical resistance of the intact abdomen during the 1-504 h postmortem period in rats.

Eight rat cadavers, at controlled ambient temperature, were each equipped with electrodes for passing current of constant intensity through the cadaver and for measurement of the potential difference between two points on the anterior abdominal skin. All electrodes were left in situ for the duration of the study, and abdominal resistance was determined at 1, 5 and 24 h post mortem, and at 24-h intervals between 24-504 h post mortem. Abdominal resistance increased during the first 5-24 h and then decreased progressively between 24-480 h (one cadaver) or 24-504 h (seven cadavers) post mortem. These findings are believed to reflect a postmortem decrease in abdominal resistivity per se.

Abdomen↗
PubMed1996

Acetylcholine muscarinic M2 receptor stimulated [35S]GTP gamma S binding shows regional selective changes in Alzheimer's disease postmortem brain.

Oxotremorine-M stimulated [35S]GTP gamma S binding was used to assess acetylcholine muscarinic M2 receptor mediated G-protein function in superior frontal cortical, superior temporal cortical and hippocampal membranes from a series of Alzheimer's disease and matched control subjects. No significant differences were seen in basal [35S]GTP gamma S binding between the groups. The maximal level of oxotremorine-M stimulated [35S]GTP gamma S binding over basal was significantly increased in Alzheimer's disease superior temporal cortex, suggesting an enhanced muscarinic M2 receptor-G-protein coupling efficiency in this region. In contrast, the maximal level of oxotremorine-M stimulated [35S]GTP gamma S binding over basal was unaltered in Alzheimer's disease superior frontal cortex and significantly reduced in Alzheimer's disease hippocampus. Western immunoblotting using antisera towards the alpha-subunits of those G-protein types known to couple muscarinic receptors, revealed that Gq alpha and Gi alpha, but not G(o) alpha, levels were significantly reduced in Alzheimer's disease superior temporal cortex. Neither Gq alpha, Gi alpha, nor G(o) alpha levels were significantly altered in Alzheimer's disease superior frontal cortex or hippocampus. These results suggest that the efficacy of muscarinic M2 receptor G-protein coupling shows regional selective changes in Alzheimer's disease postmortem brain with deficits occurring only in a region that shows severe pathology.

Age Factors↗
PubMedDate not supplied

[Changes in phospholipids in the gray and white matter of the rat brain during postmortem autolysis dynamics].

Content of total phospholipids and their individual fractions, studied in rat brain grey and white substances during postmortal autolysis, was distinctly and dissimilarly altered in these tissues and the rate of alterations depended on time of incubation. Relative content of phosphatidyl serines + sphingomyelins, phosphatidic acids + polyglycerophosphatides in grey substance as well as of phosphatidylinositides, phosphatidic acids + polyglycerophosphatides in white substance were increased, while phosphatidylinosidtides in grey substance and phosphatidyl serines + sphingomyelins in white substance were decreased within later (4 and 24 hrs) periods of autolysis. Content of phosphatidyl cholines, phosphatidyl ethanolamines, glycerophosphates and lysophospholipids was also dissimilarly altered in brain grey and white substances both within early and later periods of autolysis. The schemes of metabolic interrelations between phospholipids of rat brain grey and white substances during autolysis are considered involving hydrolase, transferase and other reactions of lipids biotransformation. This multiple complex of biochemical reactions may be among the reasons responsible for dissimilar and time-dependent deteriorations of individual brain structures after death.

Animals↗
PubMed1997

Transcellular and extracellular impedances of the intact abdomen in putrefying rat cadavers.

Total (Zt) and extracellular (Ze) abdominal impedances of putrefying rat cadavers, stored at 18.0 +/- 0.7 degrees C, were measured at 50 kHz and at 1 kHz, respectively, during the first 7 days of death. Transcellular impedance was calculated from the measured values of Zt and Ze. Total impedance and Ze increased during the first day, and then decreased with increasing postmortem interval, while Zi remained unchanged during the first 3 days before increasing more than 4-fold between 3 and 7 days postmortem. These changes are consistent with net gain of electrolyte by the extracellular fluids and with degeneration of cell membranes which occur postmortem. It is concluded that, during putrefaction, Ze is a potentially more useful index of postmortem interval than Zt or Zi, and that measurement of total abdominal impedance at 50 kHz, rather than at 10 kHz, markedly improves the precision and accuracy of impedance measurement.

Abdomen↗
PubMed1998

Changes in mechanical strength of intramuscular connective tissue during postmortem aging of beef.

We studied changes in mechanical strength during postmortem aging of bovine semitendinosus muscle using intramuscular connective tissue (IMCT) preparations from muscle stored at 4 degrees C. In the preparation, muscle fiber elements were removed, leaving a virtually intact structure of the endomysium and perimysium. The shear-force value of the IMCT preparation remained unchanged up to 10 d postmortem and decreased linearly thereafter. The yield of the perimysial fraction, which was measured as an indicator of mechanical properties of the perimysium, remained almost unchanged up to 14 d postmortem, and decreased gradually thereafter. These results suggest that the mechanical strength of the intramuscular connective tissue changes slowly during postmortem aging of beef; it remains almost unchanged for up to 10 d postmortem and progressively decreases thereafter. Thus, intramuscular connective tissue seems to affect beef tenderization in extended aging.

Animals↗