Author Archives: churchc

American Journal of Forensic Medicine and Pathology

Table of Contents  |  Vol 36 No 4 December 2015

Selected Articles:

A Decline in 2 Consecutive Postmortem Serum Tryptase Levels in an Anaphylactic Death

Homemade Firearm Suicide With Dumbbell Pipe Triggering by an Air-Compressed Gun: Case Report and Review of Literature



A simplified determination of total concentrations of Ca, Fe, Mg and Mn in addition to their bioaccessible fraction in popular instant coffee brews

Food Chemistry Volume 197, Part A, 15 April 2016, Pages 388–394;  doi:10.1016/j.foodchem.2015.10.138

A direct analysis of instant coffee brews with HR-CS-FAAS spectrometry to determine the total Ca, Fe, Mg and Mn content has been developed and validated. The proposed method is simple and fast; it delivers good analytical performance; its accuracy being within −3% to 3%, its precision – 2–3% and detection limits – 0.03, 0.04, 0.004 and 0.01 mg l−1 for Ca, Fe, Mg and Mn, respectively. In addition, Ca, Fe, Mg and Mn bioaccessibility in instant coffee brews was measured by means of the in vitro gastrointestinal digestion with the use of simulated gastric and intestinal juice solutions. Absorption of metals in intestinal villi was simulated by means of ultrafiltration over semi-permeable membrane with a molecular weight cut-off of 5 kDa. Ca, Fe, Mg and Mn concentrations in permeates of instant coffee gastrointestinal incubates were measured with HR-CS-FAA spectrometry.

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A comparison of sorptive extraction techniques coupled to a new quantitative, sensitive, high throughput GC–MS/MS method for methoxypyrazine analysis in wine

Talanta Volume 148, 1 February 2016, Pages 336–345;   doi:10.1016/j.talanta.2015.10.086

Methoxypyrazines are volatile compounds found in plants, microbes, and insects that have potent vegetal and earthy aromas. With sensory detection thresholds in the low ng L−1 range, modest concentrations of these compounds can profoundly impact the aroma quality of foods and beverages, and high levels can lead to consumer rejection. The wine industry routinely analyzes the most prevalent methoxypyrazine, 2-isobutyl-3-methoxypyrazine (IBMP), to aid in harvest decisions, since concentrations decrease during berry ripening. In addition to IBMP, three other methoxypyrazines IPMP (2-isopropyl-3-methoxypyrazine), SBMP (2-sec-butyl-3-methoxypyrazine), and EMP (2-ethyl-3-methoxypyrazine) have been identified in grapes and/or wine and can impact aroma quality. Despite their routine analysis in the wine industry (mostly IBMP), accurate methoxypyrazine quantitation is hindered by two major challenges: sensitivity and resolution. With extremely low sensory detection thresholds (~8–15 ng L−1 in wine for IBMP), highly sensitive analytical methods to quantify methoxypyrazines at trace levels are necessary. Here we were able to achieve resolution of IBMP as well as IPMP, EMP, and SBMP from co-eluting compounds using one-dimensional chromatography coupled to positive chemical ionization tandem mass spectrometry. Three extraction techniques HS-SPME (headspace-solid phase microextraction), SBSE (stirbar sorptive extraction), and HSSE (headspace sorptive extraction) were validated and compared. A 30 min extraction time was used for HS-SPME and SBSE extraction techniques, while 120 min was necessary to achieve sufficient sensitivity for HSSE extractions. All extraction methods have limits of quantitation (LOQ) at or below 1 ng L−1 for all four methoxypyrazines analyzed, i.e., LOQ’s at or below reported sensory detection limits in wine. The method is high throughput, with resolution of all compounds possible with a relatively rapid 27 min GC oven program.

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Salmonella typhimurium detection using a surface-enhanced Raman scattering-based aptasensor

International Journal of Food Microbiology Volume 218, 2 February 2016, Pages 38–43;  doi:10.1016/j.ijfoodmicro.2015.11.006

Surface-enhanced Raman spectroscopy (SERS) has been used in a variety of biological applications due to its high sensitivity and specificity. Here, we report a SERS-based aptasensor approach for quantitative detection of pathogenic bacteria. A SERS substrate bearing Au@Ag core/shell nanoparticles (NPs) is functionalized with aptamer 1 (apt 1) for the capture of target molecules. X-rhodamine (ROX)-modified aptamer 2 (apt 2) is used as recognition element and Raman reporter. Salmonella typhimurium specifically interacted with the aptamers to form Au@Ag-apt 1-target-apt 2-ROX sandwich-like complexes. As a result, the concentration of S. typhimurium was determined using this developed aptasensor structure, and a calibration curve is obtained in the range of 15 to 1.5 × 106 cfu/mL with a limit of detection of 15 cfu/mL. Our method was successfully applied to real food samples, and the results are consistent with the results obtained using plate counting methods. We believe that the developed method shows potential for the rapid and sensitive detection of pathogenic bacteria in food safety assurance.

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A rapid method for the nonselective enumeration of Yersinia enterocolitica, a foodborne pathogen associated with pork

Meat Science Volume 113, March 2016, Pages 59–61;   doi:10.1016/j.meatsci.2015.11.005

An impedance method was developed as a rapid, convenient method to enumerate pure culture of Yersinia enterocolitica. Cultures were incubated in trypticase soy broth (TSB) at 30 °C. The BacTrac™ 4000 microorganism growth analyser was used to detect impedance change of TSB representing bacteria cell numbers in the samples. Good correlations with standard plate counts were obtained (r2 > 0.95). This method is also reliable to enumerate Y. enterocolitica growing in biofilms attached to stainless steel. Compared with a standard plate count which involves dislodging biofilms from surfaces, this method is more convenient saving both time and effort. Therefore, it will be useful to study the conditions required for the biofilm growth and control of Y. enterocolitica that could be applied to the pork industry.

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The importance of post-mortem computed tomography (PMCT) in confrontation with conventional forensic autopsy of victims of motorcycle accidents

Legal Medicine Available online 23 November 2015;  doi:10.1016/j.legalmed.2015.11.005

Since traffic accidents are an important problem in forensic medicine, there is a constant search for new solutions to help with an investigation process in such cases. In recent years there was a rapid development of post-mortem imaging techniques, especially post-mortem computed tomography (PMCT). In our work we concentrated on a potential advantage of PMCT in cases of motorcycle accident fatalities. The results of forensic autopsy were compared with combined results of the autopsy and PMCT to check in which areas use of these two techniques gives statistically important increase in number of findings. The hypothesis was confirmed in case of pneumothorax and fractures of skull, spine, clavicle, scapula, lower leg bones. As for majority of other bone fractures locations and brain injures there were single cases with pathologies visible only in PMCT, but too few to reach expected level of p-value. In case of injuries of solid organs and soft tissues statistical analysis didn’t confirmed any advantage of unenhanced PMCT use. On the whole it has been shown that PMCT used as an adjunct to forensic autopsy can cause an increase in information about vitally important regions in case of motorcycle accident fatalities.

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The Changing Epidemiology of Meningococcal Disease

Infectious Disease Clinics of North America Volume 29, Issue 4, December 2015, Pages 667–677;    doi:10.1016/j.idc.2015.08.002

Neisseria meningitidis is a gram-negative, encapsulated diplococcus that exclusively infects humans. Twelve distinct serogroups have been identified based on their capsular polysaccharide, with serogroups A, B, C, W, and Y accounting for nearly all disease. In the United States, serogroup B accounts for approximately 65% of infant meningococcal disease, while serogroups C and Y caused the majority of disease
in adolescents prior to routine vaccination, and serogroup Y  predominates in the elderly.

* The incidence of meningococcal disease is currently at an historic low in the United States, but prevention remains a priority because of the devastating outcomes and risk for outbreaks.
  * Vaccines are available to protect against all major serogroups of Neisseria meningitidis circulating in the United States. These vaccines are recommended routinely for persons at increased risk for disease. In addition, adolescents are routinely recommended to receive quadrivalent meningococcal conjugate vaccine (MenACWY) starting at age 11 years.
  * Although vaccination has virtually eliminated serogroup A meningococcal outbreaks from the Meningitis Belt of Africa and reduced the incidence of serogroup C disease around the world, eradication of N meningitidis will unlikely be achieved by currently available vaccines because of the continued carriage and transmission of nonencapsulated organisms, which is not affected by the use of polysaccharide vaccines.

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