Cheng S.-C.,Institute of Forensic Medicine |
Huang M.-Z.,National Sun Yat - sen University |
Shiea J.,National Sun Yat - sen University |
Shiea J.,Kaohsiung Medical University
Journal of Chromatography A | Year: 2011
Thin layer chromatography (TLC)-a simple, cost-effective, and easy-to-operate planar chromatographic technique-has been used in general chemistry laboratories for several decades to routinely separate chemical and biochemical compounds. Traditionally, chemical and optical methods are employed to visualize the analyte spots on the TLC plate. Because direct identification and structural characterization of the analytes on the TLC plate through these methods are not possible, there has been long-held interest in the development of interfaces that allow TLC to be combined with mass spectrometry (MS)-one of the most efficient analytical tools for structural elucidation. So far, many different TLC-MS techniques have been reported in the literature; some are commercially available. According to differences in their operational processes, the existing TLC-MS systems can be classified into two categories: (i) indirect mass spectrometric analyses, performed by scraping, extracting, purifying, and concentrating the analyte from the TLC plate and then directing it into the mass spectrometer's ion source for further analysis; (ii) direct mass spectrometric analyses, where the analyte on the TLC plate is characterized directly through mass spectrometry without the need for scraping, extraction, or concentration processes. Conventionally, direct TLC-MS analysis is performed under vacuum, but the development of ambient mass spectrometry has allowed analytes on TLC plates to be characterized under atmospheric pressure. Thus, TLC-MS techniques can also be classified into two other categories according to the working environment of the ion source: vacuum-based TLC-MS or ambient TLC-MS. This review article describes the state of the art of TLC-MS techniques used for indirect and direct characterization of analytes on the surfaces of TLC plates. © 2011 Elsevier B.V.
News Article | December 5, 2016
Syphilis has plagued humankind for over 500 years. After the first reported outbreaks struck Europe in 1495, the disease spread rapidly to other continents and swelled to a global pandemic. When treatment with the antibiotic penicillin became available in the mid-twentieth century, infection rates started to decrease dramatically. Strikingly, however, infection with the bacteria Treponema pallidum subsp. pallidum (TPA) has been re-emerging globally in the last few decades; more than 10 million cases are reported annually. Yet the reason for the resurgence of this sexually transmitted infection remains poorly understood. New techniques to analyze an old disease According to the authors of the paper, little is known about the patterns of genetic diversity in current infections or the evolutionary origins of the disease. Because clinical samples from syphilis patients only contain low quantities of treponemal DNA and the pathogen is difficult to culture in the laboratory, researchers from the University of Zurich decided in 2013 to apply DNA capture and whole-genome sequencing techniques, as used by colleagues at the University of Tübingen, to ancient DNA samples. The team collected 70 clinical and laboratory samples of syphilis, yaws, and bejel infections from 13 countries spread across the globe. Like syphilis bacteria, the closely related subspecies Treponema pallidum subsp. pertenue (TPE) and Treponema pallidum subsp. endemicum (TEN), which cause yaws and bejel, are transmitted through skin contact and show similar clinical manifestations. By using genome-wide data, the researchers were able to reconstruct a phylogenetic tree showing a clear separation between the TPA lineage and the TPE/TEN lineage. "There have been many questions regarding the origin of syphilis since its appearance on the world stage 500 years ago. By combining an evolutionary and an epidemiological approach, we were able to decipher the genetic relation between strains infecting individuals today, and also trace the emergence of a pandemic cluster with high frequency of antibiotic resistance", says Homayoun C. Bagheri, former professor at the UZH Institute for Evolutionary Biology and Environmental Studies. The genomic analyses show the emergence of a pandemic cluster named SS14-Ω, which is present in contemporary infections around the globe and distinct from the cluster comprising the well-studied Nichols reference strain. "Our findings highlight the need to study more extensively the predominant strain type in the contemporary epidemic", states Natasha Arora, researcher at the Zurich Institute of Forensic Medicine and first author of the study published in Nature Microbiology. An evolutionary finding of epidemiological relevance is that the SS14-Ω cluster originated from a strain ancestor in the mid-20th century - after the discovery of antibiotics. The worrying aspect of this pandemic cluster is its high resistance to azithromycin, a second-line drug that is widely used to treat sexually transmitted infections. Natasha Arora adds: "The good news is that, so far, no Treponema strains have been detected that are resistant to penicillin, the first-line antibiotic for syphilis treatment." Co-author Philipp Bosshard from the University Hospital Zurich is continuing to collect Swiss patient samples in order to further study the clinical aspects of the work. The researchers are convinced that this type of analysis will open new opportunities to develop a comprehensive understanding of the epidemiology of syphilis - a devastating disease that persists to this day, despite the availability of treatment.
Musshoff F.,Institute of Forensic Medicine |
Madea B.,Institute of Forensic Medicine
Journal of Forensic Sciences | Year: 2012
Scientific opinions differ whether the use of stimulants causes deterioration in driving skills. In 1857 of 8709 cases of driving under the influence of drugs, amphetamine-like drugs (amphetamine, methamphetamine, and methylendioxyamphetamine) were present either alone or together with other licit or illicit drugs. In 338 cases, amphetamines were the only psychoactive substance group in plasma at mean, median, and highest concentrations of 0.18, 0.12, and 1.05 mg/L, respectively. A widespread opinion is that after the consumption of amphetamines, centrally stimulating effects with corresponding consequences on safe driving are expected. In contrast, many cases were observed that rather suggested an influence of centrally sedating substances when considering the psycho-physical conditions. Relations between concentration and effect could not be established. The apparent sedation is probably the consequence of sleep deprivation during an amphetamine binge and the after-effects of the drug. © 2012 American Academy of Forensic Sciences.
Mai M.,Institute of Forensic Medicine |
Amendt J.,Institute of Forensic Medicine
Forensic Science International | Year: 2012
By estimating the age of the immature stages of flies developing on a corpse, forensic entomologists are able to establish the minimum post-mortem interval. Blowflies, which are the first and most important colonizers, usually leave the cadaver at the end of the last larval stage searching for a pupation site. This period of development is referred as the post-feeding or wandering stage. The characteristics of the ground where the corpse was placed might be of notable importance for the post-feeding dispersal time: For pupariation the larvae prefer an environment protected from light and predators and may have a longer dispersal time in order to reach an appropriate pupation site. Hence, the dispersal time can vary and may influence the total time of development which may lead to an erroneous calculation of the post-mortem interval.This study investigates the effect of various post-feeding time intervals on the development of the blowfly . Lucilia sericata at a temperature of 25. °C. As larvae reached the post-feeding stage a pupariation substrate was offered at 0 and after 12, 24 and 48. h. Only the larvae with a dispersal time of 24. h (total time of development 325.2. h; median) and 48. h (total time of development 347.7. h; median) showed a significantly longer total development time compared to the control group (total time of development 318.4. h; median). The mortality rate did not differ between groups; however the flies that emerged from the group with a dispersal of 48. h were significantly smaller indicating increased energy consumption during dispersal.The results of this study indicate that a prolonged post-feeding stage could increase the total developmental time of . L. sericata which should be taken into consideration when interpreting entomological findings. The need for a serious examination of current rearing practices in forensic entomology laboratories is indicated because reference data sets for the time of development are usually produced by offering the post-feeding stage a substrate for pupariation immediately. © 2012 Elsevier Ireland Ltd.
Randall C.,Institute of Forensic Medicine |
Crane J.,Institute of Forensic Medicine
Journal of Forensic and Legal Medicine | Year: 2014
In the UK tramadol is a frequently prescribed opioid analgesic which is becoming increasingly popular as a drug of misuse. Its use varies worldwide and in the last decade it has been upgraded to a controlled substance in several countries, due to an increased number of deaths associated with its use. A review of all deaths associated with tramadol in Northern Ireland was performed and this highlighted 127 cases from 1996 to the end of 2012. A 10% increase in deaths due to tramadol was noted. In 2001 tramadol deaths represented 9% of all drug misuse deaths rising to 40% in 2011. The majority of the deaths occurred in males (62%), with a median age of 41 years, living in the Belfast city area (36%). Tramadol fatalities were found in combination with other drugs/medicines (49%), alcohol (36%) or alone (23%). Most of those who died did not reach hospital, with only 2% presenting with multi-organ or acute liver failure. In just over half of the deaths tramadol had not been prescribed by a medical practitioner (53%). Depression, addiction and seizures were recognised risk factors. An increase in awareness of tramadol toxicity is needed amongst the public and doctors. © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
Crane J.,Institute of Forensic Medicine
Best Practice and Research: Clinical Obstetrics and Gynaecology | Year: 2013
The accurate description and interpretation of non-genital injuries may be crucial in cases of alleged sexual assault, and may be important in corroborating a victim's statement of events. In many cases of sexual assault, non-genital injuries may be either absent or trivial; nevertheless, even minor injuries may be of significance and need to be recorded. Injuries may be result from attempts to restrain the victim, whereas others (e.g. bite marks) may have a sexual motive or be part of a sado-masochistic ritual. A standard nomenclature for injuries (i.e. using the terms 'bruises', 'abrasions', 'lacerations', 'incisions and 'stab wounds') should avoid ambiguity between medical examiners. © 2012 Elsevier Ltd. All rights reserved.
Cosbey S.H.,Forensic Science Northern Ireland |
Peters K.L.,Forensic Science Northern Ireland |
Quinn A.,Forensic Science Northern Ireland |
Bentley A.,Institute of Forensic Medicine
Journal of Analytical Toxicology | Year: 2013
Mephedrone (4-methylmethcathinone) is the beta-keto analogue of 4-methylmethylamphetamine. Before its control in April 2010, it became popular as a legal high in the United Kingdom, displacing methylenedioxymethylamphetamine as the stimulant drug of choice. The drug has stimulant and psychoactive properties, and therefore has forensic significance in criminal and morbid toxicology. The purpose of this study was to survey casework involving the drug (impaired driving and sudden death). The cases were received in the laboratory for analysis between late 2009 and the end of 2010. Analysis of blood samples for mephedrone was conducted by liquid chromatography-mass spectrometry (LC-MS). Routine screening for alcohol and a range of other pharmaceuticals and drugs of abuse was conducted using a combination of enzymelinked immunoassay, gas chromatography (GC) headspace, GC-MS and high-performance liquid chromatography with diode array detection. Mephedrone was detected in a total of 12 fatal cases. Most of these cases involved death by mechanical means; in two cases, death was attributed directly to mephedrone intoxication (blood concentrations of 2.1 and 1.94 mg/L). Mephedrone was detected in a total of 32 impaired driving cases. Blood concentrations ranged up to 0.74 mg/L (mean 0.21, median 0.10). The casework evidence in this study indicated that recreational use of the drug can produce to blood levels as high as 0.74 mg/L, although the most common value encountered is likely to lie between 0.2 and 0.3 mg/L. © The Author . Published by Oxford University Press. All rights reserved.
Zalan A.,Institute of Forensic Medicine |
Beres J.,National Center for Healthcare Audit and Improvement |
Pamjav H.,Institute of Forensic Medicine
Forensic Science International: Genetics | Year: 2011
Romanies constitute the largest minority group belonging to different subgroups in Hungary. Vlax Romanies are one of these Romani subgroups. The Gypsies came to Hungary from the Balkans in two large migrations. The Carpathian Romanies arrived in the 15th century and the Vlax Romanies came in the 19th century. The Carpathian Gypsies speak Hungarian and the Vlax Romanies speak Hungarian and Romani languages. Only a limited number of genetic studies of Y-chromosomal haplotypes/haplogroups have been done before, moreover most studies did not contain information regarding the investigated Roma populations which subgroups belong to. In the present study, we analyzed a wide set of Y-chromosomal markers to do comparable studies of the Vlax Roma in eastern Hungarian regions. The results can be compared in the context of previously published data on other Romani groups, Indian and Hungarian reference populations. Haplogroups H1a-M82 and J2a2-M67 were most common in the investigated population groups. A median-joining network of haplogroup H1a-M82 has demonstrated the sharing of identical Indian specific Y-chromosomal lineages between all Romani populations including Malaysian Indians as well as the Vlax Romanies. This common lineage of haplogroup H1a-M82 represents a common descent from a single ancestor provides a strong genetic link to the ancestral geographical origin of the proto-Gypsies. The detected haplogroups in the Vlax Romani population groups can be classified into two different Y-chromosomal lineages based on their putative origin. These lineages include ancestral Indian (H1a-M82), present-day Eurasian (J2a2-M67, J2*-M172, E1b1b1a-M78, I1-M253, R1a1-M198 and R1b1-P25) Y-chromosome lineages. Presence of these lineages in the paternal gene pool of the Roma people is illustrative of the Gypsy migration route from India through the Balkan to the Carpathian Basin. © 2010 Elsevier Ireland Ltd.
Lott S.,Institute of Forensic Medicine |
Musshoff F.,Institute of Forensic Medicine |
Madea B.,Institute of Forensic Medicine
Forensic Science International | Year: 2012
There is no toxicological analysis of gamma-hydroxybutyrate (GHB) applied routinely in cases of driving under influence (DUI); therefore the extent of consumption of this drug might be underestimated. Its consumption is described as occurring often concurrently with amphetamine or ecstasy.This study examines 196 serum samples which were collected by police during road side testing for GHB. The samples subject to this study have already been found to be positive for amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and/or 3,4-methylenedioxyethamphetamine (MDEA).Analysis has been performed by LC/MS/MS in the multiple reaction monitoring (MRM) mode. Due to its polarity, chromatographic separation of GHB was achieved by a HILIC column. To differentiate endogenous and exogenous levels of GHB, a cut-off concentration of 4. μg/ml was applied.Of the 196 samples, two have been found to be positive for GHB. Of these samples, one sample was also positive for amphetamine and one for MDMA. Whilst other amphetamine derivates were not detected in these samples, both samples were found to be positive for cannabinoids.These results suggest that co-consumption of GHB with amphetamine or ecstasy is relatively low (1%) for the collective of this study. © 2012 Elsevier Ireland Ltd.
Wohlfarth A.,Institute of Forensic Medicine
Journal of mass spectrometry : JMS | Year: 2012
An assay based on liquid chromatography/tandem mass spectrometry is presented for the fast, precise and sensitive quantitation of Δ9-tetrahydrocannabinolic acid A (THCA) in serum. THCA is the biogenetic precursor of Δ9-tetrahydrocannabinol in cannabis and has aroused interest in the pharmacological and forensic field especially as a potential marker for recent cannabis use. After addition of deuterated THCA, synthesized from D(3)-THC as starting material, and protein precipitation, the analytes were separated using gradient elution on a Luna C18 column (150 × 2.0 mm × 5 μm) with 0.1% formic acid and acetonitrile/0.1% formic acid. Data acquisition was performed on a triple quadrupole linear ion trap mass spectrometer in multiple reaction monitoring mode with negative electrospray ionization. After optimization, the following sample preparation procedure was used: 200 μL serum was spiked with internal standard solution and methanol and then precipitated 'in fractions' with 500 μL ice-cold acetonitrile. After storage and centrifugation, the supernatant was evaporated and the residue redissolved in mobile phase. The assay was fully validated according to international guidelines including, for the first time, the assessment of matrix effects and stability experiments. Limit of detection was 0.1 ng/mL, and limit of quantification was 1.0 ng/mL. The method was found to be selective and proved to be linear over a range of 1.0 to 100 ng/mL using a 1/x weighted calibration model with regression coefficients >0.9996. Accuracy and precision data were within the required limits (RSD ≤ 8.6%, bias: 2.4 to 11.4%), extractive yield was greater than 84%. The analytes were stable in serum samples after three freeze/thaw cycles and storage at -20 °C for one month. Copyright © 2012 John Wiley & Sons, Ltd.