Journal article: Temporal expression of immediate early gene mRNA during the supravital reaction in mouse brain and lung after mechanical asphyxiation

Ikematsu K, Takahashi H, Kondo T, Tsuda R, Nakasono I. – Forensic Sci Int. 2008 Jul 10. [Epub ahead of print]

Division of Forensic Pathology and Science, Unit of Social Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Nagasaki, 852-8523, Japan.

In forensic pathology, the reactions that occur in the body from somatic death to cell death are commonly termed “supravital reactions”. There are many reports of grossly visible and microscopic supravital reactions; however, few papers are available on the supravital reaction concerning gene expression. The aim of this study was to examine the gene expression of immediate early genes (IEGs) including c-fos, fos-B and c-jun in mechanically asphyxiated mouse brain and lung after somatic death and to identify the IEGs expressed at the point of supravital reaction in the brain and lung. Our results confirm that the expression of IEGs changed after death during supravital reaction and that the alterations differed according to the cause of death and the types of organ examined. In addition, IEG expression significantly increased following mechanical asphyxia. These results suggest that there is a specific pattern of gene expression following asphyxia. It is therefore important to identify the specific genes involved, as this may give significant information to aid in the post-mortem diagnosis of strangulation and hanging.

Note:

This is an interesting paper that actually mirrors slightly my PhD study, I have always suspected that protein expression/ gene is a valuable marker for determining estimation time of death. But, I have never envision that a gene is capable to give an insight on the  cause of death. My reservation of this paper is that, when death occurs all biological components will start to decompose. Based on this understanding, it is also logical to assume that all DNA and RNA will also degrade. If this occurs, the IEGs will never be detected especially in advanced cases of decomposition. What do you thing?

Journal article: Fly artifact documentation of Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) – a forensically important blowfly species in Malaysia

Fly - forensic entomologyZuha RM, Supriyani M, Omar B. ( Trop Biomed. 2008 Apr;25(1):17-22)

Forensic Science Programme, Faculty of Allied Health Science, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.

Analysis on fly artifacts produced by forensically important blowfly, Chrysomya megacephala (Fabricius) (Diptera:Calliphoridae), revealed several unique patterns. They can be divided into fecal spots, regurgitation spots and swiping stains. The characteristics of fecal spots are round with three distinct levels of pigmentation; creamy, brownish and darkly pigmented. Matrix of the spots appears cloudy. The round spots are symmetrical and non-symmetrical, delineated by irregular and darker perimeter which only visible in fairly colored fecal spots. Diameter of these artifacts ranged from 0.5 mm to 4 mm. Vomit or regurgitation spots are determined by the presence of craters due to sucking activity of blowflies and surrounded by thickly raised and darker colored perimeter. The size of these specks ranged from 1 mm to 2 mm. Matrix of the spots displays irregular surface and reflective under auxiliary microscope light. Swiping stains due to defecation by flies consists of two distinguishable segments, the body and tail. It can be seen as a tear drop-like, sperm-like, snake-like and irregular tadpole-like stain. The direction of body and tail is inconsistent and length ranged between 4.8 mm to 9.2 mm. A finding that should be highlighted in this observation is the presence of crater on tadpole-like swiping stain which is apparent by its raised border characteristic and reflective under auxiliary microscope light. The directionality of this darkly brown stain is random. This unique mix of regurgitation and swiping stain has never been reported before. Highlighting the features of artifacts produced by flies would hopefully add our understanding in differentiating them from blood spatters produced from victims at crime scenes.

Note:

This article was produced by my colleague at the Department.

Journal article: Flexible regression models for estimating postmortem interval (PMI) in forensic medicine

Institute of Legal Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain.

Correct determination of time of death is an important goal in forensic medicine. Numerous methods have been described for estimating postmortem interval (PMI), but most are imprecise, poorly reproducible and/or have not been validated with real data. In recent years, however, some progress in PMI estimation has been made, notably through the use of new biochemical methods for quantifying relevant indicator compounds in the vitreous humour. The best, but unverified, results have been obtained with [K(+)] and hypoxanthine [Hx], using simple linear regression (LR) models. The main aim of this paper is to offer more flexible alternatives to LR, such as generalized additive models (GAMs) and support vector machines (SVMs) in order to obtain improved PMI estimates. The present study, based on detailed analysis of [K(+)] and [Hx] in more than 200 vitreous humour samples from subjects with known PMI, compared classical LR methodology with GAM and SVM methodologies. Both proved better than LR for estimation of PMI. SVM showed somewhat greater precision than GAM, but GAM offers a readily interpretable graphical output, facilitating understanding of findings by legal professionals; there are thus arguments for using both types of models. R code for these methods is available from the authors, permitting accurate prediction of PMI from vitreous humour [K(+)], [Hx] and [U], with confidence intervals and graphical output provided. Copyright (c) 2008 John Wiley & Sons, Ltd. [Full text]

Notes:

This paper confirms my initial suspicion that determination time of death is not quite simple to interpret. The utilization of linear regression is unsuitable and if used would only increase error rate. Utilization data mining and various modelling algorithm would allow inclusion of other factors fro example body weight, drugs available in the body, humidity, wind speed etc. This is a very good paper and hopefully should compliment my next paper that I will be submitting at the end of this year. Keep a look out for the paper.

Crime scene construction

I had just completed my marathon lecture on Forensic Imaging. In the last lecture I had my forensic science students (session 2006/7) to take a few images where they live and stitch them together using Photoshop cs2. I had them touch up the pictures to minimize variation in each pictures. Surprisingly, they completed the assignment quite fast and I was impressed. If you are interested please jump to this HYPERLINK to enjoy the various scenery they have created. Can you figure out where they took each picture?

p.s. Could not host the images on my website as it had overwhelm my small server.