Stability of toluene and reduction of acetone to 2-propanol in homogenates of the human liver, brain and lungs

The homogenates of the livers, lungs and brains collected from five different cadavers were placed in the desiccator filled with vapours of rubber glue solvents and the concentrations of toluene, acetone and 2-propanol were determined during the 28-day storage at +25, +4 and -20 degrees C. It was demonstrated that only freezing of the material stabilised the initial concentration of these three xenobiotics while cooling to +4 degrees C resulted in limited conversion of acetone to 2-propanol and additionally reduced the biodegradation of toluene in the brain homogenates. Moreover, it was showed that at +25 degrees C the loss of acetone was almost equimolarly balanced by the 2-propanol increase, which allowed to estimate the initial concentration of acetone with the mean error of about 10%.     

STR typing of human DNA from fly larvae fed on decomposing bodies

In homicides with entomological evidence, it may be important to prove the presumed association of fly larvae to a corpse, especially if it is in doubt whether all maggots used for entomological expertise developed and fed on it. The present study demonstrates for the first time the possibility of analyzing human microsatellite DNA present in the digestive tract of necrophagous larvae that fed on decomposed bodies with a postmortem interval up to four months. The obtained human STR profiles support the association of a maggot to a specific corpse. In addition, the identification of the host species (e.g., animal source like pig) can be achieved by analysis of the cytochrome b gene. Maggots were collected from 13 corpses after various postmortem intervals and STR typing and HVR amplifications were performed using their crop contents. In seven cases, a complete STR profile was established, in two cases, an incomplete set of alleles was obtained, and in four cases, STR typing was not successful. HVR analysis was successful in all cases except one. The time of storage of the maggots and the length of the postmortem interval up to 16 weeks appeared to have no particular influence on the quality of the results.     

Causes and circumstances of fatal falls downstairs

Reports of 9156 autopsies performed at the Centre of Legal Medicine of the J.W. Goethe-University Frankfurt over a period of 10 years were reviewed for fatal accidents of falls downstairs, age, gender, drinking behaviour and alcohol influence, the locality and the time of the accident. Among 43 cases (0.47% of all autopsies) were 31 males (72.1%, average age 63.9 years) and 12 women (27.9%, average age 65.8 years). Twenty-nine accidents (67.4%) occurred at home, in six cases (14.0%) in a public building or area. Twenty-three victims (53.5%) were under the influence of alcohol (average blood alcohol concentrations (BAC): 2.56 per thousand), in 19 persons autopsy revealed severe internal disease which may explain the cause of the fall (severe coronary artery disease, myocardial hypertrophy, myocardial infarction, apoplexy, brain tumour). This study indicates that a fatal fall downstairs without an underlying severe disease or alcohol influence is a rare phenomenon.     

Quasi-experimental designs for community-level public health violence reduction interventions: a case study in the challenges of selecting the counterfactual

Objectives

We highlight the importance of documenting the step-by-step processes used for the selection of comparison areas when evaluating a community-level intervention that targets a large-scale community.

Methods

We demonstrate the proposed method using a propensity score matching framework for an impact analysis of the Cure Violence Public Health Model in Philadelphia. To select comparison communities, propensity score models are run using different levels of aggregation to define the intervention site. We discuss the trade-offs made.

Results

We find wide variation in documentation and explanation in the extant literature of the methods used to select comparison communities. The size of the unit of analysis at which a community is measured complicates the decision processes, and in turn, can affect the validity of the counterfactual.

Conclusions

It is important to carefully consider the unit of analysis for measurement of comparison communities. Assessing the geographic clustering of matched communities to mirror that of the treated community holds conceptual appeal and represents a strategy to consider when evaluating community-level interventions taking place at a large scale. Regardless of the final decisions made in the selection of the counterfactual, the field could benefit from more systematic diagnostic tools that document and guide the steps and decisions along the way, and ask: “could there have been another way of doing each step, and what difference would this have made?” Overall, across community-level evaluations that utilize quasi-experimental designs, documentation of the counterfactual selection process will provide a more fine-grained understanding of causal inference.