Teresa Magalhães

Iron levels in the human brain: a post-mortem study of anatomical region differences and age-related changes.

The link between brain iron homeostasis and neurodegenerative disease has been the subject of extensive research. There is increasing evidence of iron accumulation during ageing, and altered iron levels in some specific brain regions in neurodegenerative disease patients have been reported. Using graphite furnace atomic absorption spectrometry after microwave-assisted acid digestion of the samples, iron levels were determined in 14 different areas of the human brain [frontal cortex, superior and middle temporal, caudate nucleus, putamen, globus pallidus, cingulated gyrus, hippocampus, inferior parietal lobule, visual cortex of the occipital lobe, midbrain, pons (locus coeruleus), medulla and cerebellum (dentate nucleus)] of n=42 adult individuals (71±12 years old, range: 53-101 years old) with no known history or evidence of neurodegenerative, neurological or psychiatric disorders. It was found that the iron distribution in the adult human brain is quite heterogeneous. The highest levels were found in the putamen (mean±SD, range: 855±295μg/g, 304-1628μg/g) and globus pallidus (739±390μg/g, 225-1870μg/g), and the lowest levels were observed in the pons (98±43μg/g, 11-253μg/g) and medulla (56±25μg/g, 13-115μg/g). Globally, iron levels proved to be age-related. The positive correlation between iron levels and age was most significant in the basal ganglia (caudate nucleus, putamen and globus pallidus). Compared with the age-matched control group, altered iron levels were observed in specific brain areas of one Parkinsons disease patient (the basal ganglia) and two Alzheimers disease patients (the hippocampus).

Profiling of RNA Degradation for Estimation of Post Morterm Interval

An estimation of the post mortem interval (PMI) is frequently touted as the Holy Grail of forensic pathology. During the first hours after death, PMI estimation is dependent on the rate of physical observable modifications including algor, rigor and livor mortis. However, these assessment methods are still largely unreliable and inaccurate. Alternatively, RNA has been put forward as a valuable tool in forensic pathology, namely to identify body fluids, estimate the age of biological stains and to study the mechanism of death. Nevertheless, the attempts to find correlation between RNA degradation and PMI have been unsuccessful. The aim of this study was to characterize the RNA degradation in different post mortem tissues in order to develop a mathematical model that can be used as coadjuvant method for a more accurate PMI determination. For this purpose, we performed an eleven-hour kinetic analysis of total extracted RNA from murines visceral and muscle tissues. The degradation profile of total RNA and the expression levels of several reference genes were analyzed by quantitative real-time PCR. A quantitative analysis of normalized transcript levels on the former tissues allowed the identification of four quadriceps muscle genes (Actb, Gapdh, Ppia and Srp72) that were found to significantly correlate with PMI. These results allowed us to develop a mathematical model with predictive value for estimation of the PMI (confidence interval of ±51 minutes at 95%) that can become an important complementary tool for traditional methods.

Postmortem Analyses Unveil the Poor Efficacy of Decontamination, Anti-Inflammatory and Immunosuppressive Therapies in Paraquat Human Intoxications

Background Fatalities resulting from paraquat (PQ) self-poisonings represent a major burden of this herbicide. Specific therapeutic approaches have been followed to interrupt its toxic pathway, namely decontamination measures to prevent PQ absorption and to increase its excretion from organism, as well as the administration of anti-inflammatory and immunosuppressive drugs. Until now, none of the postmortem studies resulting from human PQ poisonings have assessed the relationship of these therapeutic measures with PQ toxicokinetics and related histopathological lesions, these being the aims of the present study. Methodology/Principal Findings For that purpose, during 2008, we collected human fluids and tissues from five forensic autopsies following fatal PQ poisonings. PQ levels were measured by gas chromatography-ion trap mass spectrometry. Structural inflammatory lesions were evaluated by histological and immunohistochemistry analysis. The samples of cardiac blood, urine, gastric and duodenal wall, liver, lung, kidney, heart and diaphragm, showed quantifiable levels of PQ even at 6 days post-intoxication. Structural analysis showed diffused necrotic areas, intense macrophage activation and leukocyte infiltration in all analyzed tissues. By immunohistochemistry it was possible to observe a strong nuclear factor kappa-B (NF-κB) activation and excessive collagen deposition. Conclusions/Significance Considering the observed PQ levels in all analyzed tissues and the expressive inflammatory reaction that ultimately leads to fibrosis, we conclude that the therapeutic protocol usually performed needs to be reviewed, in order to increase the efficacy of PQ elimination from the body as well as to diminish the inflammatory process.

DNA typing of Diptera collected from human corpses in Portugal

Medico-legal entomology, one area in the broad field of entomology, is routinely used in forensic applications. Insects are often collected from a corpse during criminal information related to the body, but requires the fast and accurate identification of the species attracted to the remains. The local entomofauna in most cases is important for explaining entomological evidence. The survey of the local entomofauna has become a fundamental first step in forensic entomological studies, because different geographical distributions, seasonal and environmental factors may influence the decomposition process and the occurrence of different species on corpses. A morphological and DNA-based methods for species identification were used in this study. Thirty-two cases are reported from indoors and outdoors conditions. Specimens were collected from corpses during autopsy procedures in the National Institute of Legal Medicine, Portugal, and cases were summarized by sex, death local, month of discovery, probable cause of death, species found and number of analyzed specimens. Just eight species, mainly Calliphoridae together with one Sarcophagidae were reported from corpses. The DNA sequencing was performed to study the mitochondrial encoded subunit I of the cytochrome oxidase gene. The aim of this work was the beginning of a database of the cadaveric entomofauna in Portugal.

Sexual abuse of children. A comparative study of intra and extra-familial cases

The existing data suggest that individuals experiencing intra-familial abuse are affected more significantly than those experiencing extra-familial abuse. This study aims to identify possible differences between these types of abuse. A retrospective study was performed based on medico-legal reports related to children suspected of being sexually abused (n=1054). The results revealed that 40.2% of the suspected abuses were intra-familial and were significantly different than extra-familial cases with respect to the following: (a) the complainants were younger; (b) their relationship to the alleged abuser was closer; (c) the alleged abusers had higher rates of previous sexual abuse; (d) the suspected abuses were less intrusive physically; (e) there was less physical but more psychological violence; (f) the delay between the last abuse and the medico-legal examination was greater; and (g) there were fewer physical signs and DNA evidence (none in the great majority of cases). These results highlight aspects of intra-familial abuse that have been identified as factors influencing the severity of its consequences - physically, these instances of abuse were less intrusive but psychologically they were more intrusive than extra-familial abuse. This justifies the use of different strategies in the diagnosis and support for victims within the family.

Firing Distance Estimation Through the Analysis of the Gunshot Residue Deposit Pattern Around the Bullet Entrance Hole by Inductively Coupled Plasma–mass Spectrometry: An Experimental Study

The use of inductively coupled plasma–mass spectrometry (ICP-MS) in the study of gunshot residues (GSR) is relatively recent, and only a few studies have been published on the subject. In the present paper, this instrumental technique has been used to study the deposit pattern of the GSR around the bullet entrance hole, through the analysis of antimony (Sb), barium (Ba), and lead (Pb). The data obtained were used to establish a mathematical model for estimating the firing distance. Test shots using a 6.35-mm pistol were made against a target of cotton tissue, and the amounts of Sb, Ba, and Pb deposited in quadrangular pieces of the target, cut from 4 radial positions, were determined by ICP-MS. In these experimental conditions, it was possible to estimate the firing distance on the interval [20–80] cm. The best linear correlation between ln m and d, where m is the mass of Sb, Ba, or Pb in the samples, expressed in μg/g of target tissue, and d the firing distance, was obtained at radial distances between 3.5 cm and 4.5 cm from the entrance hole. The best regression curve which adjusted to the data was a linear multiple regression between the firing distance and the logarithm of the mass of each element: d = a + b1X1 + b2X2 + b3X3, where X1 = ln m (Sb), X2 = ln m(Ba) and X3 = ln m (Pb). The accuracy of firing distance estimation using only 1 or 2 elements was not significantly different from the one obtained with the 3 elements.

Forensic toxicology in drug-facilitated sexual assault

Abstract The low rates of reporting, prosecution and conviction that characterize sexual assault, is likely even more evident in drug-facilitated cases. Typically, in these crimes, victims are incapacitated and left unable to resist sexual advances, unconscious, unable to fight off the abuser or to say “no” and unable to clearly remember the circumstances surrounding the events due to anterograde amnesia. The consequence is the delay in performing toxicological analysis aggravated by the reluctance of the victim to disclose the crime. Moreover since “date rape drugs” are often consumed with ethanol and exhibit similar toxicodynamic effects, the diagnosis is erroneously performed as being classical ethanol intoxication. Therefore, it is imperative to rapidly consider toxicological analysis in drug-facilitated sexual assaults. The major focus of this review is to harmonize practical approaches and guidelines to rapidly uncover drug-facilitated sexual assault, namely issues related to when to perform toxicological analysis, toxicological requests, samples to be collected, storage, preservation and transport precautions and xenobiotics or endobiotics to be analyzed.

No Cash No Whiplash?: Influence of the Legal System on the Incidence of Whiplash Injury

Whiplash injury has been a continuous source of controversy due to its association with litigation. We studied the incidence of whiplash associated disorder (WAD) in two similar socioeconomic areas and carried out a retrospective study based on the hypothesis that the Spanish law 30/1995 might have an affect on the incidence and duration of cervical symptoms and the persistence of impairment. More than 10,000 patients injured in traffic accidents were studied over a period three years. Of these, only patients with an initial diagnosis of whiplash injury were included in the study. Patients with other injuries were excluded. The patients were classified into two groups: Galicia-Spain and North-Central Portugal (depending on where the accident took place and the medico-legal evaluation procedure in force). Statistical analysis was made using SPSS 13.0 and Statistix 8.0. We found a statistically significant difference between Spain and Portugal in the incidence of WAD and in the duration of symptoms. The incongruities caused by the compulsory application of Spanish law arise from the fact that evaluation on a points scale of impairment does not always reflect the functional state of the injured person.

The consequences of orofacial trauma resulting from violence: a study in Porto

Orofacial injuries resulting from violence are a fairly common event. In Portugal, however, the impact of these injuries remains to be elucidated. This study aims to analyze the injuries and permanent consequences of orofacial trauma (in a three-dimensional perspective: organic, functional and situational), resulting from violence. To do so, a retrospective analysis of all violence-related forensic reports performed in the North Branch of the National Institute of Legal Medicine, during 2007, was carried out (n = 513). It was found that most victims were men with a mean age of 35.4 (SD = 15.1). Most aggressions were due to punches and/or kicks. The most frequent orofacial injuries were lip injuries (57.7%), followed by extra-oral soft tissue injuries (35.9%), gingival and oral mucosa injuries (29.2%), and teeth and/or periodontal injuries (17.5%). The most frequent long-term consequences concerned the teeth and periodontal area (14.0%), followed by the lip area (7.4%), and gingival and oral mucosa tissues (3.9%). In terms of the effect on functions and life situations, it was found that chewing and embarrassment in social life events were the most prevalent (43.6% and 83.6%, respectively). These results showed that orofacial trauma from violence-related events can damage a persons quality of life, especially those concerning the teeth area, as a result of their implications in normal function and in life situations.

“Foam Cone” exuding from the mouth and nostrils following heroin overdose

A “foam cone” exuding the mouth and nostrils is a recognized consequence of anoxia following pulmonary edema. In this report, we illustrate and explain this phenomenon in victims of heroin overdose.