RESUMEN

Farm animal skeletal muscle, formed through development, growth, and maturation processes, is converted to edible meat during postmortem rigor mortis and aging. Live and postmortem muscle metabolism is the phenotypic determinant of muscle characteristics and meat quality traits such as flavor and color. Meanwhile, animal muscle metabolism, originally programmed by genetic program, is modulated by feeding and environmental conditions through changes in the biosynthetic network. Metabolomics deepens our understanding of metabolisms underlying skeletal muscle growth, maturation, abnormality, and postmortem meat aging. The metabolomics approach is beneficial to explore biomarkers to monitor meat production processes and products, leading to improvements in livestock productivity and meat quality. One of the recent metabolomics findings in animal muscle could be the impact of mitochondrial activity and energy metabolisms on meat quality. The present review overviews the advances in metabolomics studies of farm animal skeletal muscle, to gain an insight into the muscle metabolisms associated with livestock production and meat quality.

Asunto(s)

Animales Domésticos , Músculo Esquelético , Animales , Músculo Esquelético/metabolismo , Rigor Mortis/metabolismo , Carne/análisis , Metabolómica

RESUMEN

BACKGROUND: Rigor mortis occurs when muscle extension vanishes through the irresistible coupling of actin and myosin by the consumption of adenosine triphosphate as energy. To clarify the cause of the differences in the progression of rigor mortis, seven fish species were used as samples. The superprecipitation reaction and Mg2+ -ATPase activity of actomyosin in dorsal ordinary muscle were measured, and the slope of the regression line between these two variables was calculated for each fish specimen. The fiber types of the dorsal ordinary muscle in each sample fish were discriminated by the stability of actomyosin ATPase at acid and alkaline preincubations. RESULT: Positive correlations were found between Mg2+ -ATPase activity and the superprecipitation reaction of actomyosin in all 27 fish specimens. The slopes of the regression lines were different not only between fish species but also in fish specimens within the same species. The area ratios of pink muscle fibers and the IIa and/or IIb subtypes of white muscle fibers in the dorsal ordinary muscle were also different between fish species, as well as in specimens within the same fish species. A positive correlation was found between the area ratios of pink muscle fibers in dorsal ordinary muscle and the slopes of the regression line. CONCLUSION: It was suggested that the differences in characteristics of rigor-mortis-related actomyosin of fish might have been caused by the differences in the interposition ratio of muscle fiber types, especially of the pink muscle fiber type, in the dorsal ordinary muscle. © 2019 Society of Chemical Industry.

Asunto(s)

Actomiosina/metabolismo , Proteínas de Peces/metabolismo , Peces/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Rigor Mortis/metabolismo , Actomiosina/química , Animales , Proteínas de Peces/química , Peces/clasificación , Fibras Musculares Esqueléticas/química

RESUMEN

Protein lysine acetylation is an post-translational modification that regulates gene expression, metabolism, cell signaling, and diseases, but its implication in the postmortem (PM) meat quality development is basically unclear. In the present study, a quantitative proteomic analysis was conducted to profile acetylome in porcine muscle within 24 h PM. In total 595 acetylation sites assigned to 163 proteins were identified in porcine muscle, of which 460 sites distributing to 110 proteins significantly changed in acetylation levels in the conversion of muscle to meat. The dynamic acetylation/deacetylaion of muscle proteins was closely associated with critical chemical-biophysical changes in PM muscle. Bioinformatic analysis revealed that protein lysine acetylation likely regulated postmortem meat quality development by regulating glycolysis and muscle pH, cell stress reponse and apoptosis, muscle contraction and rigor mortis, calcium signaling and proteolysis, IMP synthesis and meat flavor development, and even the stability of pigment proteins and meat color. This study provided the first overview of protein lysine acetylation in PM muscle and revealed its significance in the conversion of muscle to meat. Future exploration of the exact role of protein lysine acetylation at specific sites will further our understanding regarding the underlying mechanisms and be helpful for meat quality control. SIGNIFICANCE: This is the first analysis of acetylome in farm animal and postmortem muscle. Our data showed that the dynamic acetylation/deacetylation of muscle proteins was closely related to the postmortem changes of muscle that affect the final quality of raw meat. Proteins related to glucose metabolism and muscle contraction were the two largest clusters of acetylproteins identified in postmortem porcine muscle. Networks of acetylproteins involved in apoptosis, calcium signaling and IMP synthesis were identified in postmortem porcine muscle at the same time. Our results revealed that protein lysine acetylation regulated the conversion of muscle to meat. It likely regulated meat quality development by regulating postmortem glycolysis, mitochondrion initiated cell apoptosis, calcium signaling, rigor mortis, meat flavor compound sysnthesis and meat tenderization. Our study broadened our understanding of the biochemistry regulating the postmortem conversion of muscle to meat and final meat quality development, which may be helpful for future meat quality control.

Asunto(s)

Acetiltransferasas/metabolismo , Lisina/metabolismo , Proteínas Musculares/metabolismo , Músculos , Carne de Cerdo , Rigor Mortis/metabolismo , Acetilación , Animales , Contracción Muscular/fisiología , Músculos/metabolismo , Músculos/patología , Carne de Cerdo/análisis , Cambios Post Mortem , Procesamiento Proteico-Postraduccional/fisiología , Proteoma/análisis , Proteoma/metabolismo , Proteómica/métodos , Rigor Mortis/veterinaria , Porcinos

RESUMEN

At a resting sarcomere length of approximately 2.2 µm bony fish muscles put into rigor in the presence of BDM (2,3-butanedione monoxime) to reduce rigor tension generation show the normal arrangement of myosin head interactions with actin filaments as monitored by low-angle X-ray diffraction. However, if the muscles are put into rigor using the same protocol but stretched to 2.5 µm sarcomere length, a markedly different structure is observed. The X-ray diffraction pattern is not just a weaker version of the pattern at full overlap, as might be expected, but it is quite different. It is compatible with the actin-attached myosin heads being in a different conformation on actin, with the average centre of cross-bridge mass at a higher radius than in normal rigor and the myosin lever arms conforming less to the actin filament geometry, probably pointing back to their origins on their parent myosin filaments. The possible nature of this new rigor cross-bridge conformation is discussed in terms of other well-known states such as the weak binding state and the 'roll and lock' mechanism; we speculate that we may have trapped most myosin heads in an early attached strong actin-binding state in the cross-bridge cycle on actin.

Asunto(s)

Peces/metabolismo , Músculo Esquelético/metabolismo , Miosinas/química , Rigor Mortis/metabolismo , Sarcómeros/metabolismo , Aletas de Animales/fisiología , Animales , Miosinas/metabolismo , Conformación Proteica , Electricidad Estática , Sincrotrones , Difracción de Rayos X

RESUMEN

This study describes the changes taking place during rigour in springbok (Antidorcas marsupialis) Longissimus thoracis et lumborum (LTL) and Biceps femoris (BF) muscles. Samples from six male and six female springbok were snap-frozen at 2, 3, 5, 8, 12, 18, 24 and 30h post-mortem (PM) and the pH, calpains I, II and calpastatin activities and cathepsins B, BL and H activities were determined. The temperature was also recorded. Significant third-order interactions were found for the pH and temperature, with the female LTL cooling more rapidly and acidifying slower than the other samples. Female muscles were at risk of developing cold-shortening and all the samples cooled more rapidly than recommended for cattle or sheep. Cathepsin BL activity increased PM, likely due to the degradation of the lysosomes. Calpains I, II and calpastatin activity declined during rigour, indicating that the calpains were activated early PM. Gender and muscle had a significant effect on calpain and cathepsin activity.

Asunto(s)

Antílopes/fisiología , Calidad de los Alimentos , Almacenamiento de Alimentos , Carne/análisis , Músculo Esquelético/química , Rigor Mortis/veterinaria , Animales , Proteínas de Unión al Calcio/metabolismo , Calpaína/antagonistas & inhibidores , Calpaína/metabolismo , Catepsinas/metabolismo , Fenómenos Químicos , Femenino , Concentración de Iones de Hidrógeno , Isoenzimas/metabolismo , Masculino , Fenómenos Mecánicos , Músculo Esquelético/enzimología , Músculo Esquelético/metabolismo , Proteolisis , Refrigeración , Rigor Mortis/enzimología , Rigor Mortis/metabolismo , Caracteres Sexuales , Sudáfrica , Estrés Fisiológico , Estrés Psicológico/enzimología , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología

RESUMEN

To investigate the effects of chilling and partial freezing on rigor mortis changes in bighead carp (Aristichthys nobilis), pH, cathepsin B, cathepsin B+L activities, SDS-PAGE of sarcoplasmic and myofibrillar proteins, texture, and changes in microstructure of fillets at 4 °C and -3 °C were determined at 0, 2, 4, 8, 12, 24, 48, and 72 h after slaughter. The results indicated that pH of fillets (6.50 to 6.80) was appropriate for cathepsin function during the rigor mortis. For fillets that were chilled and partially frozen, the cathepsin activity in lysosome increased consistently during the first 12 h, followed by a decrease from the 12 to 24 h, which paralleled an increase in activity in heavy mitochondria, myofibrils and sarcoplasm. There was no significant difference in cathepsin activity in lysosomes between fillets at 4 °C and -3 °C (P > 0.05). Partially frozen fillets had greater cathepsin activity in heavy mitochondria than chilled samples from the 48 to 72 h. In addition, partially frozen fillets showed higher cathepsin activity in sarcoplasm and lower cathepsin activity in myofibrils compared with chilled fillets. Correspondingly, we observed degradation of α-actinin (105 kDa) by cathepsin L in chilled fillets and degradation of creatine kinase (41 kDa) by cathepsin B in partially frozen fillets during the rigor mortis. The decline of hardness for both fillets might be attributed to the accumulation of cathepsin in myofibrils from the 8 to 24 h. The lower cathepsin activity in myofibrils for fillets that were partially frozen might induce a more intact cytoskeletal structure than fillets that were chilled.

Asunto(s)

Carpas , Catepsinas/metabolismo , Frío , Proteínas de Peces/metabolismo , Congelación , Miofibrillas , Alimentos Marinos/análisis , Animales , Electroforesis en Gel de Poliacrilamida , Humanos , Miofibrillas/metabolismo , Miofibrillas/ultraestructura , Proteolisis , Rigor Mortis/metabolismo

RESUMEN

In isolated thick filaments from many types of muscle, the two head domains of each myosin molecule are folded back against the filament backbone in a conformation called the interacting heads motif (IHM) in which actin interaction is inhibited. This conformation is present in resting skeletal muscle, but it is not known how exit from the IHM state is achieved during muscle activation. Here, we investigated this by measuring the in situ conformation of the light chain domain of the myosin heads in relaxed demembranated fibers from rabbit psoas muscle using fluorescence polarization from bifunctional rhodamine probes at four sites on the C-terminal lobe of the myosin regulatory light chain (RLC). The order parameter 〈P2〉 describing probe orientation with respect to the filament axis had a roughly sigmoidal dependence on temperature in relaxing conditions, with a half-maximal change at ∼19°C. Either lattice compression by 5% dextran T500 or addition of 25 µM blebbistatin decreased the transition temperature to ∼14°C. Maximum entropy analysis revealed three preferred orientations of the myosin RLC region at 25°C and above, two with its long axis roughly parallel to the filament axis and one roughly perpendicular. The parallel orientations are similar to those of the so-called blocked and free heads in the IHM and are stabilized by either lattice compression or blebbistatin. In relaxed skeletal muscle at near-physiological temperature and myofilament lattice spacing, the majority of the myosin heads have their light chain domains in IHM-like conformations, with a minority in a distinct conformation with their RLC regions roughly perpendicular to the filament axis. None of these three orientation populations were present during active contraction. These results are consistent with a regulatory transition of the thick filament in skeletal muscle associated with a conformational equilibrium of the myosin heads.

Asunto(s)

Fibras Musculares Esqueléticas/metabolismo , Relajación Muscular/fisiología , Miosinas/metabolismo , Animales , Dextranos/farmacología , Compuestos Heterocíclicos de 4 o más Anillos/farmacología , Contracción Isométrica/fisiología , Fibras Musculares Esqueléticas/efectos de los fármacos , Fármacos Neuromusculares/farmacología , Conejos , Descanso/fisiología , Rigor Mortis/metabolismo , Temperatura de Transición

RESUMEN

Myosin crystal structures have given rise to the swinging lever arm hypothesis, which predicts a large axial tilt of the lever arm domain during the actin-attached working stroke. Previous work imaging the working stroke in actively contracting, fast-frozen Lethocerus muscle confirmed the axial tilt; but strongly bound myosin heads also showed an unexpected azimuthal slew of the lever arm around the thin filament axis, which was not predicted from known crystal structures. We hypothesized that an azimuthal reorientation of the myosin motor domain on actin during the weak-binding to strong-binding transition could explain the lever arm slew provided that myosin's α-helical coiled-coil subfragment 2 (S2) domain emerged from the thick filament backbone at a particular location. However, previous studies did not adequately resolve the S2 domain. Here we used electron tomography of rigor muscle swollen by low ionic strength to pull S2 clear of the thick filament backbone, thereby revealing the azimuth of its point of origin. The results show that the azimuth of S2 origins of those rigor myosin heads, bound to the actin target zone of actively contracting muscle, originate from a restricted region of the thick filament. This requires an azimuthal reorientation of the motor domain on actin during the weak to strong transition.

Asunto(s)

Actinas/metabolismo , Subfragmentos de Miosina/metabolismo , Tomografía con Microscopio Electrónico , Modelos Moleculares , Músculos/metabolismo , Estructura Secundaria de Proteína , Rigor Mortis/metabolismo , Grabación en Video

RESUMEN

Lairage time (short - 8min to 2.7h, n=28 vs. long - 14 to 21.5h, n=72) and pig handling (gentle - no use of stick or electric prod, pig not slipping, falling, nor emitting high-pitched vocalizations vs. rough - where any of these occurred) effects on pig stress and meat quality were measured. Blood lactate and cortisol, plus post-mortem pH (pH60min; pH24h), temperature (T60min), drip loss, sensory and instrumental color and meat quality for the longissimus dorsi, pars lumbalis derived meat were determined. Carcass rigor mortis and skin damages were measured. Lairage time significantly affected blood lactate, carcass rigor mortis, skin damages, drip loss, color and meat quality. Handling procedure influenced blood lactate, pH60min and T60min. Long lairage was more stressful, and was detrimental to carcass quality, but caused better meat quality compared to short lairage. Rough handling was related to higher lactate and lower meat quality.

Asunto(s)

Calidad de los Alimentos , Vivienda para Animales , Carne/análisis , Estrés Fisiológico , Animales , Color , Femenino , Hidrocortisona/sangre , Concentración de Iones de Hidrógeno , Ácido Láctico/sangre , Músculo Esquelético/química , Rigor Mortis/metabolismo , Porcinos , Temperatura

RESUMEN

The global meat industry has seen significant changes in the methods used to harvest and process fresh meat over the past century. Increased use of automation has led to significant increases in line speed for beef, pork, sheep, poultry and fish operations. For example, currently the fastest line observed has been broilers at 13,500/h. Such developments have required in-depth understanding of the pre and post rigor processes to prevent defects. Procedures such as maturation chilling and electrical stimulation are now common in red meat and poultry processing; allowing shorter time to deboning, while harvesting high quality meat. Robots designed to cut meat are also appearing on the market, and replacing traditional manual operations. This is a challenge, because high speed equipment is not necessarily sensitive to variations in size/quality issues, and requires development of unique sensors and control systems. Also, progress in breeding and genetics is contributing to greater product uniformity and quality; helping in operating automated equipment.

Asunto(s)

Automatización , Calidad de los Alimentos , Tecnología de Alimentos/métodos , Carne/análisis , Rigor Mortis/metabolismo , Animales , Bovinos , Frío , Estimulación Eléctrica , Peces , Manipulación de Alimentos/métodos , Concentración de Iones de Hidrógeno , Aves de Corral , Ovinos , Porcinos

RESUMEN

Forty eight lamb carcasses with temperature and pH monitored were obtained from two commercial plants. At 24h post mortem both loins (M. longissimus) from each carcass were randomly allocated to a) unaged frozen at -18°C, (b) aged at -1.5°C for 2weeks before freezing, (c) aged for 3 weeks before freezing and (d) aged for 9 weeks without freezing. Shear force, colour stability and proteolysis were analyzed. Carcasses with a slower temperature and more rapid pH decline had more calpain autolysis, slightly higher shear force and less colour stable compared to that counterpart in general (P<0.05). However, the shear force values of the loins were all acceptable (<6 kgF) regardless of different pre rigor processing and ageing/freezing treatments. Furthermore, the loins aged for 2 weeks-then-frozen/thawed had a similar shear force to the loins aged only for 9 weeks suggesting that ageing-then-freezing would result in equivalent tenderness compared to aged only loins for the long-term storage.

Asunto(s)

Manipulación de Alimentos/métodos , Carne/análisis , Músculos Paraespinales/química , Rigor Mortis/metabolismo , Animales , Calpaína/química , Color , Congelación , Humanos , Concentración de Iones de Hidrógeno , Proteolisis , Oveja Doméstica , Temperatura

RESUMEN

The original theory of postmortem rigidity has been developed and substantiated based on the concept of postmortem muscular contracture. It is postulated that the unrestricted growth of Ca2+ concentration in myoplasm of contractile cells during the immediate postmortal period brings the actin-myosine complex to the force generation state without subsequent relaxation.

Asunto(s)

Patologia Forense/historia , Modelos Teóricos , Rigor Mortis , Calcio/metabolismo , Historia del Siglo XVI , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Oxidación-Reducción , Rigor Mortis/historia , Rigor Mortis/metabolismo , Rigor Mortis/patología

RESUMEN

A gel-based phosphoproteomic study was performed to investigate the postmortem (PM) changes in protein phosphorylation of the myofibrillar proteins in three groups of pigs with different pH decline rates, from PM 1 to 24 h. The global phosphorylation level in the group with a fast pH decline rate was higher than that in the slow and intermediate groups at early PM time, but became the lowest at 24 h. The protein phosphorylation level of seven individual protein bands was only significantly (p<0.05) affected by PM time, and two protein bands were subjected to a synergy effect between PM time and pH decline rate. A total of 35 non-redundant highly abundant proteins were identified from 19 protein bands; most of the identified proteins were sarcomeric function-related proteins. Myosin-binding protein C, troponin T, tropomyosin and myosin regulatory light chain 2 were identified in the highly phosphorylated protein bands with the highest scores. The results indicate that the phosphorylation pattern of myofibrillar proteins in PM muscle is mainly changed with PM time, but only to a minor extent influenced by the rate of pH decline, suggesting that the phosphorylation of myofibrillar proteins may be related to the meat rigor mortis and quality development.

Asunto(s)

Proteínas Musculares/química , Músculo Esquelético/química , Miofibrillas/química , Fosfoproteínas/química , Cambios Post Mortem , Porcinos/metabolismo , Animales , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Miofibrillas/metabolismo , Fosfoproteínas/metabolismo , Fosforilación , Rigor Mortis/metabolismo

RESUMEN

O objetivo do presente trabalho foi caracterizar o desenvolvimento do processo de rigor mortis dos músculos Triceps brachii e Extensor/Flexor, de seis carcaças de javalis, criados semiextensivos, durante o pré-resfriamento industrial e a maciez da carne, utilizando medidas de temperatura de carcaças e da câmara de resfriamento, de pH, de comprimento de sarcômero e da força de cisalhamento, nos intervalos de tempo de 0,5; 3,0; 5,0; 7,0; 9,0; 12,0 e 24,0 horas após a sangria. A temperatura da câmara fria variou de 19,6oC (0,5h) a – 0,5oC (24h) e a temperatura média das carcaças foi de 39,07oC e 0,28oC, respectivamente. O pH médio inicial do músculo Triceps brachii foi de 6,64 e o final 5,52 e nos músculos Extensor/Flexor foi de 6,79 (0,5h) e 5,68 (24h), sendo de maior valor nos músculos Extensor/Flexor. A caracterização da contração máxima de sarcômero durante o processo de rigor mortis ocorreu na 7a hora após sangria no músculo Triceps brachii (1,61mm) e na 9a hora nos músculos Extensor/Flexor (1,63 mm) e o músculo T. brachii apresentou maior tamanho de sarcômero. As perdas por cozimento foram proporcionais à força de cisalhamento onde as amostras de carne da paleta de javali foram consideradas macias, ou seja, inferiores a 5kg.

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The objective of the present work was to characterize the development of the process of rigor mortis of the Triceps brachii and Extensor/Flexor muscles, of 06 wild boars, created semi-extensive, during the industrial pre-chilling and tenderness of the meat, using measures of temperature of carcasses and of the cold room, of pH, of sarcomere length and of the shear force, in the intervals of time of 0.5; 3.0; 5.0; 7.0; 9.0; 12.0 and 24.0 hours after exsanguination. The temperature of the cold room changed from 19.6oC (0.5h) to – 0.5oC (24h) and the mean temperature of the carcasses was from 39.07oC to 0.28oC, respectively. The mean initial pH of the muscle Triceps brachii was of 6.64 and final of 5.52 and Extensor/Flexor muscles was 6.79 (0.5h) and 5.68 (24h), being a bigger value in the muscles . Extensor/Flexor. The characterization of maximum contraction of the sarcomere during the of rigor mortis process took place in the 7th hour after exsanguination in the muscle Triceps brachii and in the 9th hour in the muscles Extensor/Flexor and the muscle Triceps brachii presented bigger sarcomere lenght. The cooking loss was proportional to the shear force where the samples of meat of wild boar shoulder were considered tender, in other words, inferior to 5kg.

Asunto(s)

Rigor Mortis/metabolismo , Sus scrofa/clasificación , Carne/análisis , Sarcómeros , Temperatura

RESUMEN

Unlike processive cellular motors such as myosin V, whose structure has recently been determined in a "rigor-like" conformation, myosin II from contracting muscle filaments necessarily spends most of its time detached from actin. By using squid and sea scallop sources, however, we have now obtained similar rigor-like atomic structures for muscle myosin heads (S1). The significance of the hallmark closed actin-binding cleft in these crystal structures is supported here by actin/S1-binding studies. These structures reveal how different duty ratios, and hence cellular functions, of the myosin isoforms may be accounted for, in part, on the basis of detailed differences in interdomain contacts. Moreover, the rigor-like position of switch II turns out to be unique for myosin V. The overall arrangements of subdomains in the motor are relatively conserved in each of the known contractile states, and we explore qualitatively the energetics of these states.

Asunto(s)

Miosinas/química , Miosinas/fisiología , Rigor Mortis/metabolismo , Transducción de Señal/fisiología , Regulación Alostérica/fisiología , Animales , Cristalografía por Rayos X , Decapodiformes/química , Decapodiformes/metabolismo , Pectinidae/química , Pectinidae/metabolismo , Conformación Proteica

RESUMEN

UNLABELLED: To investigate changes in myosin light chains (MyLCs) during postmortem aging of the bovine longissimus muscle, we performed two-dimensional gel electrophoresis followed by identification with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The results of fluorescent differential gel electrophoresis showed that two spots of the myosin regulatory light chain (MyLC2) at pI values of 4.6 and 4.7 shifted toward those at pI values of 4.5 and 4.6, respectively, by 24 h postmortem when rigor mortis was completed. Meanwhile, the MyLC1 and MyLC3 spots did not change during the 14 days postmortem. Phosphoprotein-specific staining of the gels demonstrated that the MyLC2 proteins at pI values of 4.5 and 4.6 were phosphorylated. Furthermore, possible N-terminal region peptides containing one and two phosphoserine residues were detected in each mass spectrum of the MyLC2 spots at pI values of 4.5 and 4.6, respectively. These results demonstrated that MyLC2 became doubly phosphorylated during rigor formation of the bovine longissimus, suggesting involvement of the MyLC2 phosphorylation in the progress of beef rigor mortis. KEYWORDS: Bovine; myosin regulatory light chain (RLC, MyLC2); phosphorylation; rigor mortis; skeletal muscle.

Asunto(s)

Carne/análisis , Músculo Esquelético/metabolismo , Cadenas Ligeras de Miosina/metabolismo , Rigor Mortis/metabolismo , Animales , Bovinos , Concentración de Iones de Hidrógeno , Focalización Isoeléctrica , Fosfoproteínas/análisis , Fosforilación

RESUMEN

Reddish discoloration of exposed skin areas, called frost erythema, is an important criterion for the diagnosis of fatal hypothermia. In the present study, we used immunohistochemistry in a prospective trial to show that on the molecular level, the correlate of frost erythema is hemoglobin without hemorrhage. Furthermore, we compared routine histological and immunohistochemical features of frost erythema, hematoma and livor mortis and established some criteria for their histological differentiation.

Asunto(s)

Eritema/metabolismo , Hemoglobinas/metabolismo , Hipotermia/diagnóstico , Piel/metabolismo , Anciano , Estudios de Casos y Controles , Eritema/patología , Eritrocitos/metabolismo , Eritrocitos/patología , Femenino , Patologia Forense , Humanos , Inmunohistoquímica , Masculino , Microscopía , Persona de Mediana Edad , Estudios Prospectivos , Rigor Mortis/metabolismo , Rigor Mortis/patología , Piel/patología

RESUMEN

In this study, changes in adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid levels in masseter, triceps, and quadriceps muscles obtained from right and left sides of Spraque-Dawley rats following two different types of death were investigated. The samples were taken immediately and 120 minutes after death occurred either by cervical dislocation or electric shock. ATP concentrations in the muscles of masseter, triceps, and quadriceps were lower in samples obtained 120 minutes after death than that of samples obtained immediately after death. ADP, AMP, and lactic acid concentrations in these muscles were higher in samples obtained 120 minutes after death than those obtained immediately after death. A positive linear correlation was determined between ATP and ADP concentrations in quadriceps muscles of the rats killed with cervical dislocation and in masseter muscles of the rats killed with electric shock. When the rats killed with cervical dislocation and with electric shock were compared, ADP, AMP, and lactic acid concentrations were lower in the former than in the latter for both times (immediately and 120 minutes after death occurred). In the case of electric shock, ATP is consumed faster because of immediate contractions during death, resulting in a faster rigor mortis. This finding was confirmed with higher lactic acid levels in muscles of the rats killed with electric shock than the other group. In the cervical dislocation and electric shock group rats, ATP decreased in different levels in the three different muscle types mentioned above, being much decline in masseter in cervical dislocation and in quadriceps in electric shock group. This may be caused by low mass and less glycogen storage of masseter and by near localisation of electrode to quadriceps. One can conclude that the occurrence of rigor mortis is closely related to the mode of death.

Asunto(s)

Nucleótidos de Adenina/análisis , Ácido Láctico/análisis , Músculo Esquelético/química , Rigor Mortis/metabolismo , Animales , Causas de Muerte , Vértebras Cervicales/lesiones , Electrochoque , Femenino , Masculino , Ratas , Ratas Sprague-Dawley , Traumatismos Vertebrales/metabolismo

RESUMEN

In this study, adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid in the muscles of masseter, triceps, and quadriceps obtained from right and left sides of Spraque-Dawley rats following death were investigated. The samples were taken immediately and 120 minutes after death occurred. The rats were killed either by cervical dislocation or drowning. ATP concentrations in the muscles of masseter, triceps, and quadriceps were lower in samples obtained 120 minutes after death than in those obtained immediately after death. ADP, AMP, and lactic acid concentrations in these muscles were higher in samples obtained 120 minutes after death than those obtained immediately after death. A positive linear correlation was determined between ATP and ADP concentrations in quadriceps muscles of the rats killed with cervical dislocation and in triceps muscles of the rats killed with drowning. When rats killed with cervical dislocation and with drowning were compared, ADP, AMP, and lactic acid concentrations were lower in the former than in the latter for both times (immediately and 120 minutes after death occurred). In the case of drowning, ATP is consumed faster because of hard exercise or severe physical activity, resulting in a faster rigor mortis. Higher lactic acid levels were determined in muscles of the rats killed with drowning than the other group. In the control and electric shock rats, ATP decreased in different levels in the three different muscle types mentioned above in control group, being much decline in masseter and then in quadriceps. This may be caused by lower mass and less glycogen storage of masseter. No different ATP levels were measured in drowning group with respect to the muscle type possibly because of the severe activity of triceps and quadriceps and because of smaller mass of masseter. One can conclude that the occurrence of rigor mortis is closely related to the mode of death.

Asunto(s)

Nucleótidos de Adenina/análisis , Ácido Láctico/análisis , Músculo Esquelético/química , Rigor Mortis/metabolismo , Animales , Causas de Muerte , Vértebras Cervicales/lesiones , Ahogamiento/metabolismo , Femenino , Masculino , Ratas , Ratas Sprague-Dawley , Traumatismos Vertebrales/metabolismo

RESUMEN

We examined the postmortem changes in the levels of ATP, glycogen and lactic acid in two masticatory muscles and three leg muscles of rats. The proportion of fibre types of the muscles was determined with NIH image software. The ATP levels in the white muscles did not decrease up to 1 h after death, and the ATP levels 1 and 2 h after death in the white muscles were higher than those in the red muscles with a single exception. The glycogen level at death and 1 h after death and the lactic acid level 1 h after death in masticatory muscles were lower than in the leg muscles. It is possible that the differences in the proportion of muscle fibre types and in glycogen level in muscles influences the postmortem change in ATP and lactic acid, which would accelerate or retard rigor mortis of the muscles.

Asunto(s)

Glucógeno/análisis , Fibras Musculares Esqueléticas/patología , Músculo Esquelético/química , Rigor Mortis/metabolismo , Rigor Mortis/patología , Adenosina Trifosfato/análisis , Animales , Humanos , Ácido Láctico/análisis , Masculino , Cambios Post Mortem , Ratas , Ratas Sprague-Dawley