大鼠死后脑、心肌和肾组织β-actin mRNA的降解与早期死亡时间的关系

目的 研究SD大鼠脑、心肌和肾组织细胞内β-actin mRNA的降解与早期死亡时间的关系,为早期死亡时间的推断寻找新的指标.方法 大鼠处死后置于20℃的环境中,分别于死后不同时间点提取脑、心肌、肾的总RNA,采用实时荧光定量RT-PCR方法检测总RNA中β-actin mRNA的水平(Ct值),分析死后经过时间与Ct...     

Does a Draft Really Influence Postmortem Body Cooling?*

Estimation of the time of death (TOD) is a very important task of forensic pathologist, and measurement of body temperature is a method deemed to be most precise during the initial postmortem period. The study aimed at verification of the significance of airflow present in the room where a corpse is found on body cooling process and hence on determination of the TOD. The experiment was performed in pigs during which the postmortem temperature of the eye, muscles, and rectum was recorded--in still air and with generated draft in the room. The results showed that the moderate airflow present in the experimental conditions did not significantly affect the course of cooling of the investigated body sites. Despite moderate wind generated in the room, the air movement close to pigs' bodies was actually minimal. This allowed to conclude that to evaluate the TOD most precisely, one should first have reliable data on the actual velocity of air in the direct vicinity of the body rather than relying on subjective sensation of the draft and using various unnecessary corrective coefficients for TOD calculation.     

Radiographic comparison of a fractured clavicle exhibiting a pseudo-arthrosis

Bone remodeling is a natural process that is potentially problematic for radiographic comparisons because it can occur after antemortem (AM) imaging, thus interfering with the comparability of AM and postmortem (PM) radiographs from the same individual. While the effects of age-related remodeling have been studied, limited attention has been given to trauma-related remodeling with respect to radiographic comparisons. This report adds to the latter topic by presenting a case of AM clavicle fracture that developed into a pseudo-arthrosis over a 12-month period prior to the individual's death. Even though remodeling was discernable along the fracture margins, adjacent skeletal features on the PM radiograph remained unaltered and constituted compelling evidence for the identification. This case illustrates the potential of using both normal and pathological anatomy concurrently to maximize the surety of findings from radiographic comparisons.     

Postmortem vitreous Beta-hydroxybutyrate: interpretation in a forensic setting*

Abstract: Vitreous beta‐hydroxybutyrate (BHB) was retrospectively analyzed in 1795 forensic cases using the Pointe Scientific method. Comparison of vitreous BHB with vitreous glucose in 1781 of the cases showed moderately good correlation r = 0.731. Comparison with blood alcohol levels in 1561 of the cases showed no correlation r = ?0.053. Vitreous BHB was a marker of diabetic ketoacidosis when above 6.0 mM with a vitreous glucose over 200 mg/dL. It was an indicator (>50%) for alcoholic ketoacidosis when above 6.0 mM with a vitreous glucose below 200 mg/dL. Recommendations for interpretation of vitreous BHB: <0.4 mM normal; 0.41–1.2 mM slightly elevated, rarely (<1%) of concern; 1.21–2.0 mM moderately elevated, less rarely (2.5%) of concern; 2.01–6.0 mM significantly elevated, frequently of concern (12–48%); >6.0 mM usually (100% in this study) indicated life‐threatening conditions. Vitreous BHB was helpful evaluating cases with ketogenic conditions, especially diabetes and alcoholism.     

Variation in Developmental Time for Geographically Distinct Populations of the Common Green Bottle Fly,Lucilia sericata (Meigen)*

Abstract: Time between death and discovery of remains, or postmortem interval (PMI), can be assessed using blow fly maggot age. Forensic entomologists rely on published, often nonlocal, species‐specific developmental tables to determine maggot age. In a series of common garden experiments, we investigated the developmental rate variation between populations of Lucilia sericata collected from Sacramento, CA, San Diego, CA, and Easton, MA at 16°C, 26°C, and 36°C. For the 16°C trial the time measurement started at egg hatch, while for the higher temperatures the experiment began at oviposition; the wandering stage signified the endpoint for all experiments. The distribution of developmental times differed significantly (ANOVA, p < 0.001) between the three populations within each temperature treatment. We discovered that regional variation of developmental times within a blow fly species exists. This study demonstrates the importance of assembling local population‐specific developmental tables when estimating larval age to determine PMI.     

Assessment of Wear‐Related Features of the Kerf Wall from Saw Marks in Bone*†

Abstract: Analyses of saw marks in bone may yield important information about the class characteristics of saws used in postmortem dismemberments, yet little research has been directed at identifying saws’ individualizing characteristics. This study adds to existing saw mark analysis methodologies by examining wear‐related features of kerf walls using light‐ and environmental scanning electron microscopy. A crosscut saw and hacksaw were used to create sequences of 30 cuts in bone; these sequences reveal patterns of progressive loss of fine details of kerf wall morphology with increasing saw blade wear, because of the rounding of sharp points and edges. Nevertheless, diagnostic kerf wall features used to establish class characteristics persist despite these wear‐related changes. Unsuccessful attempts at statistical analysis of wear‐related changes, based on striae width and density, suggest these patterns are not readily quantifiable. Additionally, despite the scanning electron microscope’s superior imaging capabilities, it provided few practical, methodological gains over traditional light microscopy.     

Identification of the Edentulous Individual: An Investigation into the Accuracy of Radiographic Identifications*

Abstract: The dental identification of edentulous individuals can be challenging based on the lack of antemortem materials and unique features visible on radiographs. The constant resorption of the alveolar ridges further complicates the process. The purpose of this study was to quantify the error rate and reliability of dental identifications based on a comparison of synthesized antemortem and postmortem radiographs of edentulous individuals. Ten observers examined ten cases on two occasions and reported dichotomous and conclusion level decisions. These were analyzed using Kappa and Receiver Operator Characteristics. The mean area under the curve was 0.75 and the mean sensitivity was 0.57 and specificity was 0.83. These results suggest that dental identifications of edentulous individuals using radiographs alone have a high error rate and should be dual reported. These data add further weight to the argument that all dental prostheses should be labeled.     

Growth of Chrysomya megacephala (Fabricius) Maggots in a Morgue Cooler*

Abstract: In estimating the postmortem interval (PMI) using maggots obtained during autopsy, the forensic entomologist makes decisions regarding the effects of low‐temperature storage of the body on the insects. In this case report, a corpse was found in an abandoned house in the residential area of Bukit Mertajam, Penang, Malaysia. The maggots were found to be alive inside the mouth of the deceased although the corpse had been in the morgue cooler for 12 days. The maggots were reared and identified as Chrysomya megacephala (Fabricius). The emerged adult flies were kept as a stock colony, and the duration of development under the indoor fluctuating temperature regime was studied. The total duration of developmental process of this species was 9.5 ± 0.5 days, and the PMI estimated was 3.2 ± 0.6 days. This case report demonstrates the survival of Ch. megacephala maggots for 12 days and their growth inside the morgue cooler.     

Bupropion Overdose Resulted in a Pharmacobezoar in a Fatal Bupropion (Wellbutrin®) Sustained‐release Overdose: Postmortem Distribution of Bupropion and its Major Metabolites

Bupropion (BUP) overdose commonly causes generalized seizures and central nervous system depression. The case of a 28‐year‐old woman who died from a massive lethal overdose with sustained‐release bupropion (Wellbutrin^® 300 mg) is herein presented. The autopsy revealed the presence of a pharmacobezoar consisting of at least 40 tablets in the stomach. Determination of bupropion and its active metabolites (hydroxybupropion, threobupropion, erythrobupropion) was achieved by a liquid chromatographic mass spectrometry (LC‐MS/MS) method. Postmortem concentrations for bupropion, hydroxybupropion, threobupropion, and erythrobupropion were obtained in intracranial blood, urine, bile, liver, kidney, and vitreous humor. In this case, intracranial blood level of the parent drug was 1.9 mg/L. Threobupropion was the most abundant metabolite in both blood and urine, 59.3 and 890.6 mg/L. Tissue distribution showed the highest concentration in the liver, 12.3 mg/kg. The 0.8 bupropion concentration ratio vitreous/blood suggested that vitreous could be a valuable specimen for toxicological analysis should postmortem blood be unavailable.     

An Examination of the Transition of Fracture Characteristics in Long Bones from Fresh to Dry in Central Florida: Evaluating the Timing of Injury

It is important to conduct timing of injury research analyzing fracture characteristics at known postmortem intervals (PMI) because bone can retain fresh characteristics throughout the PMI. Defleshed pig (Sus scrofa) long bones were fractured weekly in two environments (full sun and shade) over 14 weeks in Central Florida and fracture characteristics were categorized (N = 136) for analysis. Results of analysis of variance (ANOVA) using time in weeks (PMI) as a dependent variable indicate significant relationships between PMI and Fracture Angle (p < 0.001), Fracture Surface (p < 0.001), and Fracture Outline (p < 0.001). Fracture characteristics associated with perimortem trauma (smooth Fracture Surfaces and curved or V‐shaped Fracture Outlines) were commonly observed. Analysis of fracture characteristics for each environment demonstrated similar patterns. Overall, the loss of only fresh fracture characteristics for each bone was noted earlier in the PMI for the Central Florida region than previously reported.