Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroids

Tribulus terrestris is a nutritional supplement highly debated regarding its physiological and actual effects on the organism. The main claimed effect is an increase of testosterone anabolic and androgenic action through the activation of endogenous testosterone production. Even if this biological pathway is not entirely proven, T. terrestris is regularly used by athletes. Recently, the analysis of two female urine samples by GC/C/IRMS (gas chromatography/combustion/isotope-ratio-mass-spectrometry) conclusively revealed the administration of exogenous testosterone or its precursors, even if the testosterone glucuronide/epitestosterone glucuronide (T/E) ratio and steroid marker concentrations were below the cut-off values defined by World Anti-Doping Agency (WADA). To argue against this adverse analytical finding, the athletes recognized having used T. terrestris in their diet. In order to test this hypothesis, two female volunteers ingested 500 mg of T. terrestris, three times a day and for two consecutive days. All spot urines were collected during 48 h after the first intake. The (13)C/(12)C ratio of ketosteroids was determined by GC/C/IRMS, the T/E ratio and DHEA concentrations were measured by GC/MS and LH concentrations by radioimmunoassay. None of these parameters revealed a significant variation or increased above the WADA cut-off limits. Hence, the short-term treatment with T. terrestris showed no impact on the endogenous testosterone metabolism of the two subjects.     

Vitreous Humor: Biochemical Constituents in Estimation of Postmortem Interval*,†

Abstract: Analysis of biochemical constituents of the vitreous humor can be useful in determining the postmortem interval as there is proportionate postmortem rise of potassium and fall in sodium concentration. We studied 120 autopsy cases to determine the utility of potassium, sodium, calcium, and chloride levels, and sodium/potassium ratio in estimating the postmortem interval. There was a linear relationship between vitreous potassium concentration and postmortem interval, whereas an inverse relationship between vitreous sodium/potassium ratio and postmortem interval was noted. Other factors like age, sex, cause of death, season of death, and refrigeration of sample did not influence the vitreous humor potassium values. Using the statistical tools, a new formula was derived to determine the postmortem interval based on the potassium concentration and a review of previous literature is presented. Hence, the findings of this study supported a central role of vitreous humor biochemistry in many postmortem forensic and pathological evaluations.     

Study of poroscopy among South Indian population

Poroscopy is the term applied to a specialized study of pore structure found on papillary ridges of skin as a means of identification. It comes under level 3 detail of identification and hence is more reliable and accurate. The goal of this study is to estimate the importance of poroscopy for identification of individuals and to determine the gender based on frequency, type, and shape of pores. Left plain thumb prints of 200 individuals (100 men and 100 women) aged between 18 and 60 belonging to South Indian population were observed. The results have shown that women tend to have a significantly higher frequency of pores than men. Number of pores ≤ 8 pores/25 mm(2) is more likely to be of male origin and ≥9 pores/25 mm(2) is more likely to be of female origin. There was no significant sex difference based on type and shape of pores.     

ISFG: Recommendations on biostatistics in paternity testing

The Paternity Testing Commission (PTC) of the International Society for Forensic Genetics has taken up the task of establishing the biostatistical recommendations in accordance with the ISO 17025 standards and a previous set of ISFG recommendations specific to the genetic investigations in paternity cases. In the initial set, the PTC recommended that biostatistical evaluations of paternity are based on a likelihood ratio principle – yielding the paternity index, PI. Here, we have made five supplementary biostatistical recommendations. The first recommendation clarifies and defines basic concepts of genetic hypotheses and calculation concerns needed to produce valid PIs. The second and third recommendations address issues associated with population genetics (allele probabilities, Y-chromosome markers, mtDNA, and population substructuring) and special circumstances (deficiency/reconstruction and immigration cases), respectively. The fourth recommendation considers strategies regarding genetic evidence against paternity. The fifth recommendation covers necessary documentation, reporting details and assumptions underlying calculations. The PTC strongly suggests that these recommendations should be adopted by all laboratories involved in paternity testing as the basis for their biostatistical analysis.     

高效液相色谱法相对保留时间和峰高比在毒物筛选中的应用

本文用高效液相色谱法相对保留时间、２３０ｎｍ和２５０ｎｍ两个紫外检测的峰高比、荧光和２５０ｎｍ紫外检测的峰高比三个指标相结合对毒物进行筛选，３７种毒物区分率由单用保留时间区分的２４．３％提高到９４．６％，文中还考察了各种因素对相对保留时间和峰高比的影响。     

An initial evaluation of stable isotopic characterisation of post-blast plastic debris from improvised explosive devices

A number of two-way radios, similar to those which have been employed to initiate Improvised Explosive Devices (IEDs), were acquired from a commercial supplier and grouped into four pairs. Samples of plastic material were collected from five distinct regions of each radio and analysed by Infrared and Raman spectroscopy to identify the nature of the material. One radio of each pair was then subjected to detonation with a commercially available plastic explosive. The combination of radio and explosive was considered to be representative of the components of an IED. Following detonation, fragments were recovered and, where possible, identified as specific sampling points of the radio.A combination of δ²H and δ¹³C stable isotopic analysis of material from each of the five sampling points was found to provide a pattern which was characteristic of a given radio and provided a means to associate pairs of radios. When few fragments were recovered, no positive association could be made between the fragments and the paired, undamaged radio. This was attributed, in part, to manufacturing variation in the radios. However, when three or more post-blast fragments were recovered it was possible to associate these with the paired, undamaged radio with a high degree of certainty.     

A X-chromosome STR hexaplex as a powerful tool in deficiency paternity cases

The X-chromosome short tandem repeat (STR) markers have been described as very adequate tools for solving deficiency paternity cases and kinship tests when women are involved. In the absence of the alleged father, presumed paternal relationship can be more efficiently investigated by using a set of six to ten X-STR markers compared to fifteen autosomal STR. For this study, we compared the usefulness of a X-STR hexaplex developed in our laboratory (DXS7133, DXS7424, DXS8378, DXS6807, DXS7423 and DXS8377) and the commercial kit Identifiler in solving deficiency paternities. We have worked on distinct groups of caseworks involving daughters, their mothers and presumed paternal grandmothers or putative half sisters and their respective mothers. The PCR products were separated by capillary electrophoresis and detected in an ABI Prism 3100. In the majority of the caseworks (>90%), the likelihood ratio (LR) obtained by using the X-STR hexaplex was higher than the LR value observed when the Identifiler kit was used for genotyping. The combination of the two STR typing systems was able to solve all the cases.     

Classification of Glass Fragments Based on Elemental Composition and Refractive Index*

Abstract: The aim of this study was to assess the efficiency of likelihood ratio (LR)‐based measures when they are applied to solving various classification problems for glass objects which are described by elemental composition, and refractive index (RI) values, and compare LR‐based methods to other classification methods such as support vector machines (SVM) and naïve Bayes classifiers (NBC). One hundred and fifty‐three glass objects (23 building windows, 25 bulbs, 32 car windows, 57 containers, and 16 headlamps) were analyzed by scanning electron microscopy coupled with an energy dispersive X‐ray spectrometer. Refractive indices for building and car windows were measured before (RI_b), and after (RI_a) an annealing process. The proposed scheme for glass fragment(s) classification demonstrates some efficiency, although the classification of car windows (c) and building windows (w) must be treated carefully. This is because of their very similar elemental content. However, a combination of elemental content and information on the change in RI during annealing (ΔRI = RI_a?RI_b) gave very promising results. A LR model for the classification of glass fragments into use‐type categories for forensic purposes gives slightly higher misclassification rates than SVM and NBC. However, the observed differences between results obtained by all three approaches were very similar, especially when applied to the car window and building window classification problem. Therefore, the LR model can be recommended because of the ease of interpretation of LR‐based measures of certainty.     

实验性急性心肌梗死心肌K~+/Na~+、Mg~(2+)/Ca/~(2+)Zn~(2+)/Cu~(2+)比值变化的研究

用结扎家免左冠状动脉建立急性心肌梗死区的模型,探讨梗死区心肌中K~+/Na~+、Mg~(2+)/Ca/~(2+)、Zn~(2+)/Cu~(2+)比值的变化与急性心肌梗死发生时间的规律。结果提示:(1)K~+/Na~+、Mg~(2+)/Ca/~(2+)比值随心肌缺血时间延长呈进行性下降。K~+/Na~+比值在60min、120min实验组与对照组比较有显著性差异(P<0.01);(2)Zn~(2+)/Cu~(2+)比值各实验组与对照组比较无显著性差异(P>0.05),但实验组随缺血时间延长,Zn~(2+)/Cu~(2+)比值呈下降趋势,120min组比15min、30min、60min组降低约1/2(PC<0.01)。测定心肌梗死区K~+/Na~+、Mg~(2+)/Ca/~(2+)比值可以作为显示和判定急性心肌梗死的重要指标。     

海洛因来源鉴定的新方法

毒品来源的鉴定是指对毒品样品中包含的来源信息进行提取拜分析,这有助于打击毒品犯罪.海洛因是危害我国的主要毒品,它的来源鉴定更引起人们的关注.本文介绍了国际上研究海洛因来源的三种方法,即研究海洛因样品中的各种有机杂质及其相对比例;研究海洛因样品中的痕量无机元素;研究海洛因及吗啡的稳定同位素相对比值.第三种方法能够反映样品的地域性特点,因而在来源鉴定方面有突出的优势.气相色谱-燃烧-同位素比值质谱法是同位素比值测定方法中用于海洛因来源鉴定的最佳手段.这一技术还可用于其他微量物证(如炸药、药品、油品等)的来源鉴别,因而在法庭科学领域内显示了广阔的应用前景.