Early Postmortem Period Research Articles

Differential expression of calcium-regulating genes in heat-stressed turkey breast muscle is associated with meat quality

Aberrant postmortem Ca(2+)-regulation in the early postmortem period is associated with the occurrence of inferior meat quality in turkeys, described as pale, soft, and exudative (PSE). The objective of the current study was to quantify expression of 4 candidate genes responsible for maintaining Ca(2+) homeostasis in turkey skeletal muscle as a function of heat stress: α and β ryanodine receptors (RYR; Ca(2+)-release channels), the sarco/endoplasmic reticulum Ca(2+)-ATPase 1 (SERCA1), and the sarcoplasmic reticulum, Ca(2+)-storage protein calsequestrin (CASQ1). Two genetic lines of turkeys were used: a growth-selected commercial line and a randombred control line. Market-age birds were subjected to one of 5 heat stress treatments: no heat, 1 d, 3 d, 5 d, or 7 d of heat followed by 7 d of ambient temperature. Breast muscle samples were harvested and classified as normal or PSE using the meat quality parameters percentage of marinade uptake and percentage of cook loss. These parameters differed significantly by line, heat stress treatment, and meat quality status. Expression of candidate genes was measured using TaqMan quantitative PCR. Heat treatment was associated with significantly enhanced expression of αRYR, βRYR, and CASQ1 in normal muscle from both lines. Conversely, mRNA abundance of these genes was reduced in PSE muscle from both lines and recovered or increased by 7 d + 7 d of rest. Genetic line differences were observed at several time points. Expression of SERCA1 in both normal and PSE samples from both lines was unchanged or trended downward with heat stress. Taken together, genetic line and heat-stress treatment affected the expression of important Ca(2+)-regulating genes in association with meat quality status. The data suggest that birds whose meat leads to PSE may fail to respond to heat stress appropriately due to a delay in the upregulation of the important calcium-regulating genes: αRYR, βRYR, and CASQ1.

High post-mortem temperature combined with rapid glycolysis induces phosphorylase denaturation and produces pale and exudative characteristics in broiler Pectoralis major muscles

This study investigated the effect of early post-mortem temperature on broiler protein characteristics and meat quality. Muscles were kept at different temperatures (0, 20 and 40 °C) until 4 h post-mortem and then stored at 4 °C. Rapid degradation of ATP and glycogen, thus inducing a high rate of lactate formation and pH drop, were found in the 40 °C group during incubation. When extracting proteins, a lower protein content of the sarcoplasmic fraction and a higher protein content of the myofibrillar fraction were found in the 40 °C group at 24 h post-mortem; SDS-PAGE and western-blotting results revealed that phosphorylase was associated with the myofibrillar fraction. Furthermore, the 40 °C group had paler surfaces, higher drip loss and lower processing properties. These data suggest that elevated temperature during early post-mortem period, resulting in rapid glycolysis, induced phosphorylase denaturation and association with myofibrillar proteins thus generating pale and exudative characteristics.

Effects of genetic markers and implant strategy on longissimus and gluteus muscle tenderness of calf-fed steers and heifers1

Effects of genotype (GEN) and implant program (IMP) on LM and gluteus muscle (GM) tenderization were investigated using crossbred steer (n = 185) and heifer (n = 158) calves. The 3-marker GeneSTAR Tenderness panel [CAST (calpastatin), CAPN1 316 (µ-calpain), and CAPN1 4751 (µ-calpain)] was used to determine the GEN of each animal (reported as total number of favorable alleles, 0 through 6). Calves were randomly assigned to 1 of 2 IMP, conventional (CNV) or delayed. Cattle in the CNV group were implanted at the beginning of the finishing period with Revalor-IS or Revalor-IH (Intervet Inc., Millsboro, DE), and then reimplanted 59 d later with Revalor-S or Revalor-H (Intervet Inc.). Calves in the delayed group received a single terminal implant (Revalor-S or Revalor-H) administered 45 d after initiation of the finishing period. Warner-Bratzler shear force (WBSF) was measured on LM and GM steaks at 3, 7, 14, 21, and 28 d postmortem. No interactions between the main effects of sex, IMP, or GEN were detected (P > 0.05) for WBSF. An IMP × postmortem aging (age) interaction was detected (P < 0.05) for LM and GM WBSF. For both muscles, steaks from CNV cattle had WBSF values that were approximately 0.2 kg greater (P < 0.05) than the values for steaks from delayed animals, but only during the early postmortem period (3 to 7 d). A linear effect of GEN on WBSF was detected (P < 0.05) for LM and GM steaks. Within each muscle, steaks from cattle with 6 favorable alleles had WBSF values 0.33 kg less than the values for steaks from cattle with 1 favorable allele. The GEN × age interaction was not significant for LM (P = 0.14) or GM (P = 0.20), but a numerical trend was observed for the effect of GEN on WBSF to diminish as age increased. To investigate how genetic markers could be interfaced with current beef carcass quality grading, cattle were sorted into 2 gene marker groups (GMG), ≤3 vs. ≥4 favorable alleles. For both muscles, GMG was effective only at identifying tenderness differences within the Select grade. When aged ≤14 d, Select LM steaks from cattle with ≥4 alleles had smaller (P < 0.05) WBSF values than did LM steaks from animals with ≤3 alleles. Preslaughter factors (sex, IMP, and GMG) controlled in the present study each accounted for less than 7% of the explained variation in tenderness of the test population. Results from this study suggest that the 3 GeneSTAR Tenderness markers were associated with small differences (0.33 kg) in WBSF and may be useful for increasing the consistency of Select beef, but these specific markers accounted for only a minor amount of variation in beef tenderness.

Effects of camptothecin, etoposide and Ca 2+ on caspase-3 activity and myofibrillar disruption of chicken during postmortem ageing

Recently, a novel consideration has focused on the potential relationship of apoptosis and the protease caspases and the underlying mechanism for meat postmortem tenderization. In this study, apoptosis inducers, camptothecin and etoposide as well as Ca 2+ were used to treat chicken muscle immediately after slaughter and follow the changes in caspase-3 activities and changes in the myofibrillar structures during 7 days of ageing. All three treatments resulted in significantly higher caspase-3 activities during storage (p < 0.05), with the natural substrates, whereas Western blotting analysis of the α-spectrin cleavage product, 120 kDa peptide (SBDP 120), showed that Ca 2+ was more effective than either camptothecin or etopside, and all were most active up to day 3 (p < 0.01). According to SDS-PAGE, each treatment enhanced the accumulation of the 30 kD Troponin-T degradation product, especially during the first 3 days (p < 0.05), and this was supported by the degradation of myofibrils observed by electron microscopy (TEM). TEM images showed the treatments resulted in enlargement of the I-bands and shrinkage of A-bands; however Z-lines were only slightly affected, even at day 7. The findings revealed that the three apoptosis inducers could increase myofibrillar dissociation and proteolysis during the first 3 days of chicken meat ageing. Because of the high activity of caspase-3 during the early postmortem period, it is possible that caspase-3 contributes to the conversion of muscle into meat.

The Potential Use of the Eye Temperature Decrease in Determining the Time of Death in the Early Postmortem Period

The experiment was performed in pigs during which the postmortem body temperature was continuously measured. The study was focused on a period of time starting 0.5 hours after the animals' termination and consisted in computer recording of the cooling process of the eyeball (vitreous humor), orbit soft tissues, muscles, and the rectum. The experiment revealed the absence of a plateau phase of temperature decrease in eyeball and orbit soft tissues contrary to muscles and rectum, what demonstrates that temperature measurements in the eye could become an alternative method of determining the time of death during the initial phase of postmortem cooling. During this early postmortem period determination of the time of death based on measurements of the rectum or muscles temperatures due to existing plateau is not possible.

Elevated Body Core Temperature in Medico-Legal Investigation of Violent Death

Pathologically elevated body core temperature, measured at the death scene, is an important finding in medico-legal investigation of violent deaths. An abnormally high rectal temperature at any death scene may point to an underlying pathology, the influence of certain drugs or a hidden cerebral traumatism, and death by suffocation which would remain undetected without further medico-legal investigations. Furthermore, hyperthermia and fever, if unrecognized, may result in an erroneous forensic estimation of time since death in the early postmortem period by the "Henssge method." By a retrospective study of 744 cases, the authors demonstrate that hyperthermia is a finding with an incidence of 10% of all cases of violent death. The main causes are: influence of drugs, malignant tumors, cerebral hypoxia as a result of suffocation, infections, and systemic inflammatory disorders. As a consequence it must be stated, that hyperthermia must be excluded in every medico-legal death scene investigation by a correct measurement of body core temperature and a comparison between the cooling rate of the body and the behavior of early postmortem changes, notably livor and rigor mortis.

Evaluation of postmortem S100B levels in the cerebrospinal fluid with regard to the cause of death in medicolegal autopsy

Previous studies have suggested the usefulness of the postmortem serum S100B level as a marker of the severity of brain damage. In this study, we investigated the S100B level in the cerebrospinal fluid (CSF) in serial autopsy cases ( n = 216, within 3 days postmortem), including those of blunt injury ( n = 34: fatal head injury, n = 20; others, n = 14), sharp instrument injury ( n = 9), mechanical asphyxiation ( n = 19), drowning ( n = 11), fire fatality ( n = 26), intoxication ( n = 20), hypothermia (cold exposure, n = 16), hyperthermia (heat stroke, n = 9), acute cardiac death ( n = 52) and pneumonia ( n = 20). The CSF S100B level showed a moderate postmortem time-dependent increase for acute cardiac death ( r = 0.58, p < 0.0001) and asphyxia ( r = 0.741, p < 0.001). In cases of survival time within 48 h, drowning and hypothermia usually showed a lower CSF S100B level (around 500 ng/ml), and the level was higher for delayed head injury death, asphyxia, intoxication, and hyperthermia (around 1500 ng/ml) ( p < 0.05). In fatal head injury cases, however, CSF S100B did not correlate with the survival time or postmortem interval. A CSF S100B level of >2000 ng/ml in the early postmortem period might be considered a biochemical sign of fatally severe brain damage.

Mechanisms of γ-hydroxybutyric acid production during the early postmortem period

Although postmortem production of γ-hydroxybutyric acid (GHB) has been confirmed, its production pathways and substrates have not been sufficiently clarified. To confirm that the residual enzymes are involved in GHB production during the early postmortem period, endogenous GHB concentrations in the postmortem blood and liver samples obtained from charred cadavers were compared with those from noncharred cadavers within 50 h after death. The endogenous GHB concentrations in blood and the livers of charred cadavers were significantly lower than those of noncharred cadavers, showing that heat denaturation of enzyme proteins had prevented the postmortem GHB production. In addition, in vitro experiments with rabbit liver homogenates were carried out for inhibition of postmortem GHB production by specific enzyme inhibitors; N-formylglycine (succinic semialdehyde dehydrogenase inhibitor), valproic acid [γ-aminobutyric acid (GABA) aminotransferase inhibitor], pyrazole (alcohol dehydrogenase inhibitor), or N,N-diethyldithiocarbamic acid (aldehyde dehydrogenase inhibitor) was added and incubated, and the inhibition of GHB production was then measured. The results showed that the inhibition ratios by N-formylglycine, valproic acid, and pyrazole were 74.0%, 10.4%, and 17.7%, respectively. This suggests that the contribution ratios of the GHB-producing pathways originating from succinic acid, GABA/putrescine, and 1,4-butanediol are about 70%, 10%, and 20%, respectively.

Postmortem Artifacts Made by Ants and the Effect of Ant Activity on Decompositional Rates

Ants belong to the family Formicidae of the order Hymenoptera and they are one of the world's dominant insect groups. Ants can be present at all stages of carrion decomposition as they are typically observed shortly after death or during the early postmortem period, but even later once the fly maggots had left the body. Their role in the faunal succession varies from predator on the eggs and larvae of other insects (mainly Diptera), thus reducing significantly the rate of decomposition, to scavenger on the flesh or exudates from the corpse itself. As they can deeply affect the occurrence of cadaver entomofauna, the presence or absence of ants should be taken into account in every case involving postmortem interval estimates based on entomological evidence. In fact, the effects of ants on carrion reduction seem to be mainly dependent on species, on their amount or abundance, and on geographic area. The feeding action of ants can cause many irregular, serpiginous, scalloped areas of superficial skin loss, and small punctate and scratch-type lesions may be often observed on the body, which are the result of postmortem ant bites. Usually ant injuries are orange-pink to yellow in color and diffusely scattered over the skin surface. These injuries consist of small and rather shallow gnawed holes that can be easily misinterpreted as antemortem abrasions or resulting from strong acids. No bleeding is associated with such skin lesions but sometimes considerable hemorrhage can take place, especially where removal of superficial layers of skin occurs in congested parts of the body. As ants attack the uncovered areas of the body, ant bites can frequently give rise to suspicion especially if located on the neck mimicking antemortem injuries. They are also occasionally misinterpreted as patterned abrasion due to the imprinted effect of a blunt or offending object. On closer inspection, artifacts made by ants can be immediately apparent especially when the ants are identified upon the body, but final diagnosis can be only confirmed at the autopsy by gross and microscopic analysis. The features of such lesions will be illustrated in detail by reviewing some interesting forensic cases.

Postmortem identification of hyperglycemia

The detection of diabetic coma postmortem requires accurate biochemical analysis. Due to continuous consumption of glucose by surviving cells postmortem, blood glucose levels decrease rapidly. Therefore, vitreous fluid has been used as a substitute in forensic practice, since it has a very low cell count. It has been repeatedly reported that the sum value of vitreous glucose and lactate should be used to estimate the original antemortem blood glucose level, based on the assumption that pre-existing glucose is gradually converted to lactate under anaerobic conditions during agonal phase and the early postmortem period. In this study, we applied a strategy including consistent sampling of vitreous fluid from the centre of both eyes of deceased subjects as soon as possible after arrival at the morgue, and immediate bedside analysis using a blood gas instrument. In total, 3076 cases were included during 2004–2006. We found that, after an initial drop of vitreous glucose during the very early postmortem period, the levels stayed stable for appreciable time postmortem. Analysis of a second sample collected at autopsy 1–3 days later gave similar results ( R 2 = 0.90). In contrast, the vitreous lactate levels showed a steady increase. This implies that the sum value of glucose and lactate increases with postmortem time, as reflected by vitreous potassium level. In fact, a statistically significant difference in the sum value was seen between subjects with potassium below 10 mmol/L ( n = 1086) and above 20 mmol/L ( n = 531), p < .001. In addition, in this large material, we did not identify a single case with circumstantial indication of hyperglycemia that only showed high vitreous lactate. We therefore suggest that vitreous glucose alone should be used to diagnose hyperglycemia postmortem and that the limit of 10 mmol/L should have a good specificity for diabetic coma, which theoretically would equal an original blood glucose value of about 26 mmol/L. As to the methodology, we found that sonication, centrifugation and addition of fluoride to the samples are unnecessary procedures when using a blood gas instrument. The strategy resulted in a doubling of the number of diabetic coma identified at our department compared to preceding period when analysis only was performed on selected cases.

Criminal Investigations

Determination of the time since death in the early postmortem period is one of the most critical issues to be faced by criminal investigators. One of the techniques is the evaluation of the pupil pharmacological reactivity. In the present work, we aim at identifying whether an objective and single method, based on pharmacological pupil reaction, is feasible or not. Between 2002 and 2003 calendar years, we observed 309 bodies, whose eyes have been each instilled apart, within 26 hours since death, with either a myotic substance or a mydriatic solution. Our results show that the real effectiveness of pupil pharmacological reactivity as method for assessing the time since death in early postmortem period is not only questionable but even highly misleading if not replaced by alternative objective physiological tests and appropriate professional judgments by the investigators.

Aldehyde fixation is not necessary for the formation of “dark” neurons

Kherani and Auer [6] recently reported a study in Acta Neuropathologica relating to the mechanism of the formation of “dark” neurons. Their observations led them to suggest that (1) both in vivo and during the early postmortem period, glutamate release and transmembrane ion Xuxes cause some perturbation in a proportion of neurons, which become shrunken, hyperchromatic under the light microscope, and condensed, hyperelectron-dense at the ultrastructural level, but only while aldehyde Wxation is underway, (2) the shrinkage/condensation is executed by transmembrane ion Xuxes or by actin Wlaments, and (3) everything considered, the formation of “dark” neurons is a biotic process. This idea was logically deduced in part from the results of an experiment dealing with the formation of the artefactual “dark” neurons of Cammermeyer (i.e., neurons formed even in normal brain tissue when removed from the skull without previous transcardial aldehyde Wxation followed by a 24-h delay [1]), and in part from the earlier experience of neuropathologists that artefactual “dark” neurons are generally not encountered either in autopsy materials when the postmortem period is long or after nonaldehyde Wxation. Furthermore, they assumed that this idea also applies to the nonartefactual “dark” neurons produced in vivo by ischemia, hypoglycemia, or epilepsy. In a number of communications (reviewed by [3]), our team have postulated another mechanism, which unfortunately is not mentioned in their study. This mechanism postulates that, in each neuron, the intracellular spaces among the ultrastructural elements of conventional transmission electron microscopy are Wlled with a continuous trabecular gel consisting of proteins, ions and water; this gel stores noncovalent (mechanical) free energy, at the expense of which a volume-shrinking phase transition can spread throughout its whole soma-dendrite domain in response to a chemical or a physical noxa (for the existence and importance of such gels in cell biology, see [10]). The pivotal observations supporting this mechanism were as follows: (1) if initiated by physical (nonbiotic) noxae, the formation of “dark”-neurons took place even under conditions that were extremely unfavorable for enzyme-mediated (biotic) processes [4, 7, 9], (2) independently of the nature (physical or chemical) of the initiating noxa and of the circumstances (favorable or unfavorable for enzymatic processes) of the “dark”-neuron formation, the excess water appeared in neighboring astrocytic elements, but not in the surrounding extracellular space [2–9] (the “destination” of transmembrane ion Xuxes), and (3) in each in-vivo case we investigated [2, 5, 8], both the recovering and the dying “dark” neurons displayed ultrastructural signs proving indisputably that they had been compact and electron-dense even long before aldehyde Wxation. To obtain direct evidence against the role of aldehyde Wxation in the formation of the nonartefactual “dark” neurons, we produced “dark” granule neurons in the hippocampal dentate gyrus of four anesthetized living rats via a single condenser discharge, and in the neocortex of four other anesthetized living rats via a pin puncture head injury (for the methodological details and the animal care, see [2]). In each group, two rats were immediately Wxed by the transcardial perfusion of 500 ml of a 3:1 mixture of methanol and chloroform, while the cut-oV heads of the other rats were subjected to Wxation by microwave irradiation (continuous 750 W, controlled 80°C, 1 min). The brains were removed from the skull 1 day later [1] and processed (without aldehyde postWxation) for electron microscopy as usual. P. Bukovics · J. Pal · F. Gallyas (&) Department of Neurosurgery, University of Pecs, 7623 Ret utca 2, Pecs, Hungary e-mail: ferenc.gallyas.sen@aok.pte.hu

Tissue-specific differences in mRNA quantification of glucose transporter 1 and vascular endothelial growth factor with special regard to death investigations of fatal injuries

Glucose transporter 1 (GLUT1) and vascular endothelial growth factor (VEGF) have been established as being responsible for cellular adaptation to oxygen deficiency in tissue ischemia and hypoxia mediated by hypoxia-inducible factor 1. We hypothesized that mRNA quantification of these factors in autopsy tissue specimens could have diagnostic significance for investigating the pathology of death, especially after injury. Various cases (total, n = 119; less than 48 h postmortem) were examined, including fatal blunt injury ( n = 71) and sharp instrument injury ( n = 18), as well as asphyxia (strangulation/hanging, n = 12) and acute myocardial infarction/ischemia ( n = 18) as controls. Quantification of mRNA by TaqMan real-time RT-PCR and immunostaining were performed for GLUT1 and VEGF in lung, kidney, and skeletal muscle specimens. The postmortem interval showed no significant influence on the relative quantification of mRNA during the early postmortem period. Characteristic results were found in blunt injury cases: both GLUT1 and VEGF mRNAs decreased in the lung but increased in the skeletal muscle depending on survival time. In the kidney, subacute deaths showed higher GLUT1 mRNA levels compared with acute deaths from blunt injury, but no significant change was found for VEGF mRNA. Immunohistochemistry showed visually predominant GLUT1 immunoreactivity in the renal cortex for cases with a longer survival time, coincident with the results at the mRNA level. Tissue-specific differences in mRNA quantification of GLUT1 and VEGF shed light on tissue ischemia/hypoxia and subsequent tissue-dependent pathophysiological changes leading to death after injury.

Postmortem serum nitrogen compounds and C-reactive protein levels with special regard to investigation of fatal hyperthermia

The present study analyzed serum levels of urea nitrogen (UN), creatinine (Cr), and C-reactive protein (CRP), which are very stable during the early postmortem period, for investigation of the cause of death with special regard to hyperthermia (heat stroke) in serial medico-legal autopsy cases (n = 429), excluding fatal injury, intoxication, and fire fatality. In this series, mechanical asphyxiation, drowning, and sudden cardiac death cases (n = 56, n = 43, and n = 212, respectively) usually showed low levels within postmortem reference ranges for these serum markers, although UN and CRP levels were mildly elevated in cases of sudden cardiac death and cerebrovascular stroke. There were concomitant significant elevations in serum levels of UN (>50 mg/dL), Cr (>2 mg/dL), and CRP (>2 mg/dL) for chronic renal failure, gastrointestinal bleeding, pneumonia, and hypothermia (cold exposure). UN and CRP were especially high for chronic renal failure and pneumonia, respectively. However, hyperthermia cases showed an isolated elevation in the serum Cr level, suggesting an influence of systemic skeletal muscle damage. These serum markers may be practically useful for postmortem investigation of death due to hyperthermia (heat stroke), for which specific pathological and toxicological evidence may not be available.

Expression Levels of mRNAs for Catecholamine Biosynthetic Enzymes as Markers of Acute Response to Contusion Stress during the Early Postmortem Period

Various stresses can be followed by sudden unexpected deaths, and autopsies sometimes fail to identify pathological findings that determine the cause of death. Pathologists occasionally explain such deaths as being due to overstimulation of sympathoadrenal systems, but postmortem assessment of antemortem sympathoadrenal activity has not been established. An animal model of weight injuries was used to quantify sympathoadrenal response to contusion stress, which is common in forensic fields. A weight was dropped from a given height onto the right dorsal limb of each anesthetized rat, with a control group and three stress groups (n = 4, each): 1000 g-80 cm, 1000 g-40 cm, and 500 g-40 cm. To explore the postmortem changes, we also included ten groups comprised of control and 1000 g-80 cm groups, whose tissues were harvested during 12 hours after euthanasia. Real-time quantitative polymerase-chain reaction was performed to quantify relative expression levels of mRNAs for catecholamine biosynthetic enzymes in the adrenals and the anterocervical ganglia: tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). The expression levels of all target mRNAs in the adrenals increased with the intensity of impact (TH, p < 0.0005; DBH and PNMT, p < 0.005), and particularly, TH mRNA level exhibited near-stepwise elevation (p < 0.05). In contrast, no significant differences were detected in the anterocervical ganglia. Moreover, these mRNA levels in the adrenals decreased with increasing postmortem interval length. Thus, TH mRNA level may be a good marker of sympathoadrenal response to contusion stress during the early postmortem period.

Effects of Dehairing Methods and Sex on Pork Quality and Boar Taint Compound Levels in Tissues

The objective of this study was to investigate the effects of dehairing methods and sex on various traits of pork quality, as well as on tissue levels of the boar taint compounds androstenone and skatole. At the early postmortem period, dehided pigs showed higher muscle pH levels (p<0.05), lower temperatures (p<0.05) and lower drip loss (p<0.001) than scalded pigs. Thus, the dehairing method can affect the early postmortem glycolytic rate and water-holding capacity. Moreover, the differences in meat quality traits between the genders were small, and not considered to have practical importance. The scalding method had only a limited effect on the androstenone content. On the other hand, the scalded entire males exhibited a lower content of skatole than the dehided entire males (p<0.01). These results appear to indicate that the heating treatment from the scalding process influenced the reduction of skatole content

Influence of myosin heavy- and light chain isoforms on early postmortem glycolytic rate and pork quality

This study addressed the influence of the content of myosin heavy- (MHC) and light chain (MLC) isoforms on early postmortem glycolytic rate and meat quality traits in the porcine longissimus muscle. The fast-glycolysing group showed lower contents of MHC slow and MLC 1s isoforms ( P < 0.05), and higher MHC fast isoform contents than the normal-glycolysing group ( P < 0.05). The MHC fast/slow ratio was correlated with lactate content ( r = 0.41) and early postmortem muscle pH ( r = −0.51), and the content of the MLC 1s isoform was negatively correlated with lactate content and glycolytic potential ( r = −0.38 and −0.36, respectively). Hence, both the MHC and MLC isoforms did influence metabolite contents, thus also affecting glycolytic rate, and suggested that the myosin isoforms, in particular the MHC isoforms, might also have some bearing on the extent of protein denaturation and pork quality during the early postmortem period.

Predicting longissimus dorsi texture characteristics in beef based on early post-mortem colour measurements

Sixty young bulls of Pirenaica breed that were representative of the beef production and marketing systems in Northern Spain were studied. The following parameters were determined with the aim of predicting beef texture characteristics of the longissimus dorsi based on the objective measurements taken on the carcass at the early post-mortem period: colour measurement (CIE L ∗ a ∗ b ∗) readings were taken on the latissimus dorsi (LTD), rectus abdominis (RA), and longissimus dorsi (LD) muscles. In this study, it was observed that more information on beef tenderness is obtained with colour measurements taken on the carcass LTD and RA, and LD at 24 h post-mortem. However, the regression analysis showed that beef TI from Pireanica young bulls can be predicted quite accurately by C ∗ measured on the RA muscle just 45 min after slaughter.

Postmortem cardiac troponin T levels in the blood and pericardial fluid. Part 2: Analysis for application in the diagnosis of sudden cardiac death with regard to pathology

Although previous forensic pathological studies have suggested the possible application of cardiac troponins in the diagnosis of myocardial infarction, there appears to be insufficient data with regard to its cardiac pathology. The present study analyzed the heart blood, peripheral blood and pericardial fluid levels of cardiac troponin T (cTnT) in sudden cardiac deaths ( n=96) within 48 h postmortem in relation to pathological findings of acute myocardial infarction (AMI, n=34), recurrent myocardial infarction (RMI, n=23), ischemic heart disease without any pathological evidence of infarction (IHD, n=24) and other heart diseases (OHD, n=15). Control groups ( n=75, survival time <24 h) within 48 h postmortem consisted of asphyxiation ( n=35), drowning ( n=27) and cerebrovascular diseases ( n=13). There was a marked correlation in the cTnT levels between right and left heart blood samples. The pericardial level was usually higher than either heart blood level, and the external iliac venous blood level was the lowest. Although postmortem time-dependent increases in heart and pericardial blood cTnT levels were observed in most groups, they were most evident for AMI and asphyxiation. In the early postmortem period (<12 h) there was no significant difference between AMI or RMI and the other groups except for drowning. After 12 h postmortem, significantly elevated heart blood and pericardial cTnT levels were observed for AMI and RMI showing multiple interstitial hemorrhages and necrosis compared to those with localized eosinophilic changes or patchy interstitial hemorrhages, IHD and OHD. These differences were the smallest for peripheral blood. For sudden cardiac death cases, the difference in cTnT level at each site among the causes of death was independent of gender, age, heart or lung weight and pathologies of affected coronary artery and severity of coronary stenosis. These observations suggest that the elevation in postmortem blood and pericardial cTnT levels in sudden cardiac death may depend on the severity of ischemic myocardial damage including the size and intensity of myocardial lesions involving multiple interstitial hemorrhages and necrosis, and also the postmortem period for heart and pericardial levels.

Precision of estimating the time since death using different criteria of supravital muscular excitability.

Supravital electrical excitability of skeletal muscle is an important method of estimating the time since death in the early postmortem period, which further narrows down the limits of death-time estimation resulting from body cooling. Compared with the subjective grading of muscular excitability, the precision of death-time estimation could already be raised by objectifying the muscular contraction. Criteria for extrapolation of the time since death by objectified muscular contraction are decrease of the maximum force using definite stimuli, increase of the relaxation time, and increase of the galvanic threshold.In an original investigation comprising 71 cases, the first 50 served as reference, whereas the remainder served as the control sample.To re-evaluate the data on the precision of death-time estimation the data was remodeled and matched reference and control samples regarding beginning of the investigation and duration of electrical excitability, age, and so on, were formed. Twenty-eight cases were available for matched reference and control samples. For the reference group, calculations on the accuracy of death-time estimation were carried out and were checked with the independent control group. The following questions were examined on these remodeled reference and control samples: 1. Would death-time estimation be more precise when using the postmortem interval as a dependent or independent variable? 2. Are there any differences between contralateral muscle groups? 3. Are there differences between muscles in the duration of electrical excitability? 4. Can the original data on the precision of death-time estimation be confirmed on the remodeled reference and control sample? The most relevant new result is that when using the postmortem interval as a dependent variable, a much higher precision of death-time estimation can be achieved. There are no differences between contralateral muscles as far as the criteria for extrapolation of the time since death are concerned and the thenar and hypothenar muscles are excitable over a much longer period of time than the biceps bracchii muscle.