Scanning electron microscope study of the lung in drowning

The authors describe the results obtained using the scanning electron microscope (SEM) to study drowned lungs and control lungs. Results are compared with a previous study carried out using laboratory animals. The results from both studies are analogous, in the absence of chronic pulmonary emphysema. The diagnosis of chronic pulmonary emphysema is simple with the SEM even when dealing with autoptic material obtained 24 to 48 h after death, but the diagnosis of drowning becomes difficult in lungs with chronic emphysema.     

微波消解-扫描电镜联用检测脏器内硅藻

目的介绍一种微波消解-扫描电镜联用检测脏器内硅藻的新方法。方法大白兔30只,随机分为生前溺死组（n=15）和死后溺尸组（n=15）。提取兔肺、肝、肾、股骨骨髓和现场珠江水样,采用建立的微波消解-扫描电镜联用法检测脏器组织和水样中的硅藻,并与硝酸乙醇消解-扫描电镜联用的方法进行比较。结果生前溺死组的兔肺、肝、肾、股骨骨髓组织中大多数观测到与现场珠江水样一致的硅藻,微波消解-扫描电镜联用法检测脏器内硅藻的平均含量分别为：2505.2个/2g肺,18.7个/10g肝,6.5个/10g肾,6.3个/0.5g骨髓;肺与肝、肾、骨髓检出硅藻的阳性比例为86.7%,脏器硅藻检出含量和硅藻检验阳性比例均明显高于硝酸乙醇消解-扫描电镜联用法所测值。死后溺尸组的兔脏器组织均未观测到硅藻。结论微波消解-扫描电镜联用法检测脏器内硅藻,高效、安全、环保,硅藻检验灵敏度高,降低了劳动强度,提高了定性定量分析准确度,且能有效避免污染,在法医学溺死鉴定中具有良好的应用价值。     

Scanning electron microscopy of incinerated teeth

The aim of the present scanning electron microscopy study was to document the nature of morphologic changes occurring in human enamel and dentin subjected in vitro to temperatures in the range of 200-1,000 degrees C for variable times. The results of the investigation confirm that human enamel and dentin remain microscopically identifiable after incineration at 1000 degrees C. Furthermore, these tissues remain identifiable after incineration at 1,000 degrees C for periods greater than 3 h. No consistent or reliable differences in morphology could be detected in enamel or mineralized dentin incinerated in the temperature range 200-600 degrees C. Temperature-dependent changes involving the predentin zone were observed. Following incineration at 800 degrees C for over 3 h and at 1,000 degrees C for 3 h, a metamorphosis of enamel and dentin into a globular form was observed.     

微波消解-扫描电镜联用法在溺死诊断中的应用

目的探讨微波消解-扫描电镜联用法在溺死诊断中的应用价值。方法收集已知死因的尸体标本105例,其中水中尸体85例(生前溺死70例,死后抛尸入水15例),陆地自然死亡尸体20例。水中死亡案例同时收集落水处水样。分别用微波消解-扫描电镜联用法(方法 A)和硝酸破机-光镜联用法(方法 B)对上述尸体的离体肺、肝、肾、骨髓组织及水样进行硅藻定性、定量检测。结果①溺死尸体的肺、肝、肾、骨髓中及落水处水样硅藻检出率:A法分别为100%、94.3%、92.9%、82.9%、100%,硅藻检验阳性率为100%;B法分别为90%、62.9%、51.4%、28.6%、92.9%,硅藻检验阳性率为65.7%。②两种方法检出的硅藻种类与落水处水样中硅藻的种类均一致。③两种方法在死后入水尸体离体的肺中也检出少量硅藻(<3个/2g肺组织),但在死后入水尸体的其它脏器及陆地自然死亡尸体脏器中均未检出硅藻。结论微波消解-扫描电镜联用法较硝酸破机-光镜联用法对尸体离体组织脏器中的硅藻检出率高,方法灵敏,定性准确。     

Scanning electron microscopy analysis of experimental bone hacking trauma

The authors report on their macro- and microscopy study of bone lesions made by a sharp force instrument (a single blade knife), and a sharp-blunt instrument classified as a chopping weapon (a hatchet). The aim of this work was to attempt to identify the instrument by analyzing the general class characteristics of the cuts. Each weapon was used on human bones. The results indicate that macroscopic analysis is more problematic. The microscopic analysis assessed that characteristics examined were effective in distinguishing sharp from sharp-blunt injury to the bone. The microscope facilitates analysis unachievable with macroscopic methods, some three-dimensional characteristics not visible to the naked eye being clearly defined with its use. Emphasis has been placed on the value of SEM as an anthropologist's tool in bone lesion injuries.     

Scanning electron microscopy determination of string mozzarella cheese in gastric contents

As part of a suspected homicide investigation, a sampling of the gastric contents from the victim was forwarded to the U.S. Food and Drug Administration's Forensic Chemistry Center (FCC) for analysis of specific, selected components. The victim was known to have consumed string mozzarella cheese, as a snack, less than 24 h before his disappearance and the subsequent discovery of the body. The investigation sought to confirm or dismiss speculation the victim may have been fed a meal or eaten additional food prior to his death. Analysis of the stomach contents involved examination by stereoscopic light microscopy (SLM) and isolation, processing, and analysis of suspect materials by scanning electron microscopy (SEM). Several wax-like, off-white to cream-colored objects were noted by SLM examination and removed from the gastric contents. Through a series of fixation, sectioning, drying, and coating steps, these objects were prepared for analysis by SEM. Comparison of the suspect material with laboratory control string mozzarella cheese showed excellent correlation between the analyzed samples, confirming the suspect material from the stomach contents as string mozzarella cheese.     

Scanning electron microscopy as an auxiliary method in the study of exhumed bones

Scanning electron microscopy (SEM) has been used in forensic science in many ways. The reports of cases in which SEM has been used as an auxiliary method in the investigation of exhumed bones are rare. In this article, we report an exhumation that was made to determine if a seized weapon could have been used in a homicide. We used SEM to analyze a fracture in the interior of the skull of the victim. The findings described in this article showed us that it is possible to develop new researches in this field.     

Scanning electron microscopy analysis of experimental bone hacking trauma of the mandible

The authors report on a macroscopic and microscopic study of human mandible bone lesions achieved by a single-blade knife and a hatchet. The aim of this work was to complete the previous data (scanning electron microscopy analysis of bone lesions made by a single-blade knife and a hatchet, on human femurs) and to compare the lesions of the femur with those of the mandible. The results indicate that the mandible is a more fragile bone, but the features observed on the mandible are quite similar to those previously observed on the femur. This work spells out the main scanning electron microscopy characteristics of sharp (bone cutting) and blunt (exerting a pressure on the bone) mechanisms on human bone. Weapon characteristics serve to explain all of these features.     

溺死鉴定中硅藻检验的应用

在法医学检案中,溺死诊断以及入水地点的判定一直是重点和难点之一,硅藻检验被认为是一种相对可靠的诊断溺死的方法,而根据硅藻的群落特征推断其入水区域具有一定的可信度。对不同水域内硅藻进行研究,可为溺死鉴定及入水区域的判定提供参考。本文就硅藻相关的生物学特性、检验方法等相关的国内外研究进展进行综述,供法医学工作者在相关科研和检案实践中参考。     

Quantitative analysis of sharp-force trauma: an application of scanning electron microscopy in forensic anthropology.

Scanning electron microscopy (SEM) has occasionally been used by anthropologists and forensic scientists to look at morphological characteristics that certain implements leave on bone. However, few studies have addressed techniques or protocols for assessing quantitative differences between tool marks on bone made by different bladed implements. In this study, the statistical variation in cut mark width was examined between control and test samples on bone using a scalpel blade, paring knife, and kitchen utility knife. Statistically significant differences (p < .0005) were found between cut marks made by the same knife under control and test conditions for all three knife types used in the study. When the control sample and test samples were examined individually for differences in mean variation between knife types, significant differences were also found (p < .0005). While significant differences in cut mark width were found, caution should be used in trying to classify individual cut marks as being inflicted by a particular implement, due to the overlap in cut mark width that exists between different knife types. When combined, both quantitative and qualitative analyses of cut marks should prove to be more useful in trying to identify a suspect weapon. Furthermore, the application of SEM can be particularly useful for assessing many of these features.     

Autopsied cases of drowning in Denmark 1987-1989.

In the 3-year period 1987-1989, 219 drowning cases were submitted to medico-legal autopsy in Denmark. The demographic data including the manner of death and the external findings are reported. In 74 accident cases analysis for blood-alcohol concentration was performed. In 53% a concentration of more than 0.1% was found. In 91 drowning cases (age more than 18 years and where the time interval in the water was less than 24 h) the average weight of both lungs was 1.411 g, compared to 994 g in 20 control cases. In 7% of the drowning cases the weight was less than 1.000 g, so called dry lungs. Finally the weight of the lungs and the amount of pleural transsudate in relation to the time interval in the water were registered in 198 cases. For a longer time interval in the water the weight of the lungs decreased, while the amount of pleural transsudate increased. By adding these two parameters, the combined weight was between 1.000 and 2.200 g in more than 75% of the cases as long as the interval in the water was less than 30 days.     

Incised wound margins caused by steel blades. Scanning electron microscopy to determine wound direction

The aim of this paper has been to check the diagnostic ability of Scanning Electron Microscopy (S.E.M.) to determine wound direction. We have studied incised wound margins caused by steel blades in human skin samples from cadavers by S.E.M. It was found that a lateral accessory tail existed in 65% of the entrance edges. This finding was recorded in all the cases when wound direction was perpendicular to Lancer's lines of the skin area in which the wound was located. No similar finding in the exit tails was noticed. The depth and length of the wound margins was less accurate an index of the wound direction than a lateral accessory tail. We think that this finding could be useful in determining the entrance margin in incised wounds.     

Pediatric drowning: a 20-year review of autopsied cases: III. Bathtub drownings

Bathtub drownings are a significant cause of mortality in the pediatric population. Infants and preambulatory children are disproportionately affected, and several studies have suggested that preventative campaigns have been ineffective in the prevention of such deaths. To obtain a better understanding of the factors associated with bathtub drownings, a retrospective review of autopsy records over a 20-year period (1984-2003) was performed. Eighteen consecutive cases of bathtub drownings were identified in 8 males and 10 females (ratio, 0.8; P = 0.6374). The age ranged from 6 months to 70 months (mean, 17 months; median, 11 months), and most cases occurred in infants aged 12 months or less (72%). Males tended to be older than females (mean, 23 months versus 11 months; P = 0.1889). Associated factors included inadequate adult supervision (89%), cobathing (39%), the use of infant bath seats (17%), and coexistent medical disorders predisposing the infant or child to the drowning episode (17%). The pathologic findings included a frothy exudate (28%), pleural effusion (28%), and increased lung weight (61%). All toxicologic samples submitted for analysis were negative. The present study highlights the factors associated with bathtub drownings and may aid in the prevention of such deaths in the pediatric population.     

Prevalence of diatom frustules in non-vegetarian foodstuffs and its implications in interpreting identification of diatom frustules in drowning cases

Detection of diatom frustules in bone marrow (diatom test) is used for diagnosing ante-mortem drowning where the usual signs of drowning are not present in dead bodies recovered from water. However, controversies over the reliability of diatom test results are continuing. There have been indications on the possibilities of diatoms entering into systemic circulation from atmospheric air, food and drink. While diatoms have been demonstrated in the gut content of edible marine forms such as shrimps and clams, the present study, for the first time, provides empirical evidence on the prevalence as well as abundance of diatom frustules in the samples of cooked non-vegetarian foodstuffs that impend human consumption in Kelantan, Malaysia. It is found that 50 g each of cleaned and cooked prawns and of clams impending human consumption contain about 8360 and 29,054 diatom frustules, respectively. A person accustomed to prawn and clam food would be ingesting an estimated 2 million diatoms in a single year. Considering the suggestion that detection of five diatom frustules in 10 g of bone marrow would suffice for concluding drowning as mode of death, and the fact that there is yet no proof that diatom frustules do not enter into the human systemic circulation through the digestive tract, the estimated number of diatom frustules routinely ingested acquires significance since entry of a few of such ingested frustules into the systemic circulation can lead to false positive test results. The findings of this research raise two important issues: first, population based routine food related diatom ingestion requires to be estimated, and, second, studies have to be initiated to categorically prove or disprove the possibility of entry of diatom frustules into the systemic circulation via the digestive tract.     

Pediatric drowning: a 20-year review of autopsied cases: I. Demographic features

Drowning is a significant cause of childhood mortality in the developed world. Males and preschool-aged children are overrepresented in most series of pediatric drowning. To obtain a better understanding of age- and gender-related factors, a retrospective review of autopsy records over a 20-year period (1984-2003) for cases of drowning (exclusive of bathtub drownings) was performed. Sixty-three consecutive cases of drowning were identified in 45 males and 18 females (ratio 2.5; P = 0.0007). The ages ranged from 9 months to 17 years, and most cases occurred in the 0- to 4-year age group (57%). Boys tended to be older than girls (5 years 9 months versus 4 years 4 months; P = 0.2133). Sites of drowning were open water (48%) and pools (44%), with children drowning in open water being significantly older than those drowning in pools (6 years 6 months versus 4 years 6 months; P = 0.0462). Most boys drowned in open water (53%), whereas most girls drowned in pools (50%). Resuscitation was attempted after the drowning episode in 84% of cases, with children aged 4 years or less having significantly higher rates than older children (P = 0.0346). The present study highlights differences in the pattern of drowning according to age and sex and may aid in developing targeted educational and preventative campaigns.     

Pediatric drowning: a 20-year review of autopsied cases: II. Pathologic features

The pathologic findings in autopsies of drowning victims are nonspecific and vary from case to case. However, most reported pathologic series of drowning cases exclude children and do not take into consideration the unique circumstances surrounding bathtub drownings. In addition, the effect of resuscitation on the autopsy findings has not been studied in children. A retrospective review of autopsy records of non-bathtub drownings from a 20-year period (1984-2003) was performed and 63 cases were identified in 45 males and 18 females (age range 9 months to 17 years). The incidence of frothy exudate, pleural effusion, and increased lung weight was 43%, 36%, and 80%, respectively. The incidence of frothy exudate and the combination of all 3 factors was significantly higher in cases with no resuscitation compared with those cases with attempted resuscitation with or without delayed death. As the interval between the drowning episode and autopsy increased, the incidence of frothy exudate decreased significantly. There was no relationship between these findings and the age and sex of the decedent. Other clinical conditions or occult pathologic findings that may have contributed to death were found in 8 cases (13%). The findings highlight the need for thorough clinicopathologic correlation in cases of drowning to accurately interpret the pathologic findings.     

The ultrastructure of the electric burn in man: a transmission electron microscopy-scanning electron microscopy study

The authors describe the ultrastructural aspects of the electric burn observed with the transmission electron microscope (TEM) and the scanning electron microscope (SEM). With the TEM the most apparent feature is the homogenization and arrangement of the filamentous cytoplasmic material in elongated and parallel bundles together with elongation of the nuclei and junctional structures. SEM studies present a three-dimensional vision of the filamentous material that confirms and clarifies the cellular deformation as a whole. An hypothesis is advanced suggesting that the phenomenon is due to the effects produced by the extremely rapid dehydration of the tissue or that the electric current and Joule effect can act upon the filaments and contractile proteins, causing the cell deformation.     

Suicidal drowning in south Florida.

Autopsy protocols at the office of the Chief Medical Examiner were reviewed with respect to suicidal drowning. Between July 1, 1994 and June 30, 1998, there were 267 drownings and 873 people committed suicide in Broward County, Florida. Of those, 25 were suicidal drownings, representing 2.86% of all suicides, and overall the 8th leading cause of suicidal death. When considering suicide in the age group of 65 years and older, (n = 239), which accounts for 19.8% of the population and 27.4%, of all suicides, drowning represents 6.7% of all suicidal deaths, and within females in this group represents the third most common form of suicidal death (13.8%). The presence of alcohol or other drugs is less usual in elderly suicide victims than younger victims. Of the 25 drowning suicides, there was a preference for swimming pools, canals, and lakes as the locations of choice. Additional drowning and suicide related criteria were evaluated including marital status, mental health, clothing worn, previous attempts or threats, suicide notes, and personal effects at the scene; with the intention of establishing a profile for drowning by suicide. Given the relative abundance of water, the suicidal drowning rate appears to be lower than what might otherwise be anticipated.