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At least 487 records · Page 27Linked to original sources
PubMed2004

Combined high-field 13C CP MAS NMR and low-field NMR relaxation measurements on post mortem porcine muscles.

Changes in postmortem muscle characteristics are investigated in muscles from eight pigs exposed to different combinations of preslaughter stress (exercise on treadmill) and stunning method (CO(2) vs electrical stunning). Solid-state (13)C cross-polarization (CP) magic-angle spinning (MAS) NMR experiments are carried out on a total of 16 rapidly frozen M. longissimus muscle biopsies taken in vivo the day before slaughter and at 45 min postmortem. Simultaneously, low-field NMR T(2) relaxation time measurements are carried out on samples from M. longissimus. Glycogen and lactate are estimated from the (13)C CP MAS spectra, and correlations of r = 0.89 and r = 0.70, respectively, to subsequent biochemical determinations using partial least squares regression (PLSR) are established. Moreover, PLSR reveals that, besides the 72 ppm signal (carbons in glycogen), a signal around 38 ppm, which increases concomitantly with lactate, is also significantly correlated to changes in glycogen/lactate. With the assumption that the 38 ppm signal reflects CH(2) in phosphocreatine/creatine, altered mobility of creatine as a result of dephosphorylation is indicated. Finally, PLSR on the 45 min (13)C CP MAS spectra also reveals correlation (r = 0.54) to the slowest relaxing T(2) population (50 min postmortem), known to reflect extra-myofibrillar water. Subsequently, evaluation of the loading plot in the PLSR analysis reveals that the correlation exclusively is associated to the 52 ppm resonance intensity. With the assumption that this resonance reflects methyl groups in choline/phosphatidyl choline, the intensity changes in the 52 ppm resonance imply alterations in membrane properties. Accordingly, the data indicate a relationship between membrane properties and the amount of water being expelled from muscle cells postmortem, which supports the hypothesis that disruption of membranes is implicated in the postmortem mobilization of muscle water.

Animals↗
PubMed1995

Heat-shock cognate 70 messenger RNA expression in postmortem human hippocampus: regional differences and age-related changes.

In situ hybridization of postmortem human brain tissue showed that constitutive heat-shock cognate 70 (hsc 70) mRNA was expressed in more than 50% of the pyramidal neurons in the hippocampal subfields. The ratio (%) of the hsc 70 mRNA-expressing neurons to the total neurons was significantly greater in CA3 and the hilus than in CA1 and CA2. The lower ratio in CA1 may be related to its vulnerability to various stresses. The ratio of hsc 70 mRNA-expressing neurons in CA1 was significantly greater in the older subjects than in the younger ones. This may reflect the up-regulated hsc 70 mRNA induction in response to a reduction in free hsc 70 because the binding of hsc 70 to aberrant proteins may be increased in aged persons.

Adult↗
PubMed1994

Photometric measurement of pressure-induced blanching of livor mortis as an aid to estimating time of death. Application of a new system for quantifying pressure-induced blanching in lividity.

A newly developed digital system employs photometric measurement of pressure-induced blanching of livor mortis to estimate time of death. The conventional method of applying pressure with thumb or forceps relies largely on subjective interpretation. Our system improves on this method by photometric quantification of color changes produced by defined magnitudes of pressure. We tested the new system by applying increasing levels of pressure to lividity in 50 cadavers with known time of death. Characteristics courses for pressure-induced changes were found for the brightness component of livor mortis, revealing distinct differences between the respective postmortem intervals. The surface areas under these curves were then calculated and distributed into 10-hour postmortem time categories. Variance analysis of these surface values revealed clear differences between the time categories, especially in the medians. Distinct differences between the various postmortem time categories were also evident for the chroma component of livor mortis. The new system offers a further method--in addition to body temperature, rigor mortis, and the electrical responsiveness of skeletal muscles--for estimating time of death, especially after long postmortem intervals.

Equipment Design↗
PubMedDate not supplied

[Forensic medical assessment of late cadaveric changes in examination of dismembered corpses].

The investigation was made of dismembered corpses parts in time aspect. Various conventional features of the late postmortem period were under consideration: corpse potherb, emphysema, maceration of the skin. The time of manifestation of rotten transformation of a corpse was specified for each dismembered part: the head, the upper and lower parts of the body, the extremities. The results allow the investigator to define time of death by each fragment of a dismembered corpse.

Body Temperature↗
PubMed1988

Human trabecular meshwork organ culture: morphology and glycosaminoglycan synthesis.

Human corneoscleral explants were maintained for several weeks in defined, serum-free media. Trabecular cell vitality, as judged by vital stain exclusion, is high for at least one month. Trabecular ultrastructure, as compared to that of fresh eyes, first shows minor cellular and extracellular matrix degradation after 3 weeks in culture. The biosynthetic profiles of trabecular glycosaminoglycans (GAGs) change significantly by 3 weeks in culture. Eyes that are stored at 5 degrees C for up to 48 hr postmortem exhibit changes in trabecular ultrastructure and in GAG profiles; both characteristics return to normal by 7 days in culture. The incorporation pattern of 35S-sulfate and 3H-glucosamine into the GAGs of the trabecular meshwork (TM) is distinct from corneal or scleral incorporation. The relative incorporation of 3H-glucosamine into trabecular GAGs, as determined by sequential enzymatic degradation, is: 22.3% hyaluronic acid (HA), 27.9% chondroitin sulfate (CS), 21.3% dermatan sulfate (DS), 5.9% keratan sulfate (KS), 17.7% heparan sulfate (HS) and 4.9% unidentified material. The relative incorporation of 35S-sulfate into trabecular GAGs is: 0% HA, 32.9% CS, 34.8% DS, 7.7% KS, 13.8% HS and 11.1% into unidentified material. This profile is in good agreement with the profile that was previously obtained for human and nonhuman primate meshworks prior to culture. We conclude that corneoscleral explant organ culture is a useful tool for extracellular matrix studies within a time window from 7 to at least 14 days in culture.

Aged↗