Post-Mortem Interval and Microbiome Analysis through 16S rRNA Analysis: A Systematic Review.

The determination of the Post-Mortem Interval (PMI) is an issue that has always represented a challenge in the field of forensic science. Different innovative approaches, compared to the more traditional ones, have been tried over the years, without succeeding in being validated as successful methods for PMI estimation. In the last two decades, innovations in sequencing technologies have made it possible to generate large volumes of data, allowing all members of a bacterial community to be sequenced. The aim of this manuscript is to provide a review regarding new advances in PMI estimation through cadaveric microbiota identification using 16S rRNA sequencing, in order to correlate specific microbiome profiles obtained from different body sites to PMI. The systematic review was performed according to PRISMA guidelines. For this purpose, 800 studies were identified through database searching (Pubmed). Articles that dealt with PMI estimation in correlation with microbiome composition and contained data about species, body site of sampling, monitoring time and sequencing method were selected and ultimately a total of 25 studies were considered. The selected studies evaluated the contribution of the various body sites to determine PMI, based on microbiome sequencing, in human and animal models. The results of this systematic review highlighted that studies conducted on both animals and humans yielded results that were promising. In order to fully exploit the potential of the microbiome in the estimation of PMI, it would be desirable to identify standardized body sampling sites and specific sampling methods in order to align data obtained by different research groups.

Pathology of callosal damage in ALS: An ex-vivo, 7 T diffusion tensor MRI study.

OBJECTIVES: The goal of this study was to better understand the changes in tissue microstructure that underlie white matter diffusion changes in ALS patients. METHODS: Diffusion tensor imaging was carried out in postmortem brains of 4 ALS patients and two subjects without neurological disease on a 7 T MRI scanner using steady-state free precession sequences. Fractional anisotropy (FA) was measured in the genu, body, and splenium of the corpus callosum in formalin-fixed hemispheres. FA of the body and genu was expressed as ratio to FA of the splenium, a region unaffected in ALS. After imaging, tissue sections of the same segments of the callosum were stained for markers of different tissue components. Coded image fields were rated for pathological changes by blinded raters. RESULTS: The FA body/FA splenium ratio was reduced in ALS patients compared to controls. Patchy areas of myelin pallor and cells immunostained for CD68, a microglial-macrophage marker, were only observed in the body of the callosum of ALS patients. Blinded ratings showed increased CD68 + microglial cells in the body of the corpus callosum in ALS patients, especially those with C9orf72 mutations, and increased reactive astrocytes throughout the callosum. CONCLUSION: Reduced FA of the corpus callosum in ALS results from complex changes in tissue microstructure. Callosal segments with reduced FA had large numbers of microglia-macrophages in addition to loss of myelinated axons and astrogliosis. Microglial inflammation contributed to reduced FA in ALS, and may contribute to a pro-inflammatory state, but further work is needed to determine their role.

Insectos de importancia forense en cadáveres de cerdo (sus scrofa ) en La Paz Bolivia / Forensic insects in pig carcasses (sus scrofa) in La Paz Bolivia

Resumen:La Entomología Forense es una ciencia que implica el estudio de las especies antropofágicas que practican un ciclo vital en el cadáver. Contribuye en la determinación del Intervalo posmortem. Los insectos de importancia forense que se estudiaron pertenecen a la orden Dípteros y Coleópteros. En el estudio realizado en el municipio de Pucarani, ubicado en la provinciaLos Andes del Departamento La Paz a 3852 m.s.n.m. entre otoño e invierno, se obtuvo dos ejemplares de cerdo S. scrofa, en dos ambientes: abierto (cerdo A) y cerrado: (cerdo B). Se identificó 339 especímenes entre dípteros y coleópteros. No se encontraron diferencias significativas en la sucesión de entomofauna entre ambos ambientes, sin embargo predominó la familia Fannide sp. en el lugar cerrado por ser un ambiente húmedo. Los dípteros de mayor importancia son: Sarconesia Chlorogaster, Clorobrachycoma splendida, que pertenecen a la familia Calliphoridae, que se mantuvo en constante actividaden su estadio larval y su forma adulta en los cuatro estados de descomposición a temperaturas de 14 - 16°C, humedad relativa de 30%; no se encontró a Calliphora nigribasis en la descomposición avanzada; Sarconesiopsis magellánica solo se presenta en la etapa Fresco. Entre los Coleópteros: Oxelitrum apicale apareció desde la etapa hinchado. La sucesión de entomofauna cadavérica y su particularidad en cada etapa de descomposición, es el elemento que nos ayudaría a determinar el IPM, que dependerá de las condiciones climáticas a gran altitud como Bolivia.

Abstract:Forensic entomology is a science that involves the study of the cannibalistic species that plays a vital cycle in the body. It helps to determinate the postmortem interval. Insects with forensic importance that were studied belong to the order Diptera and Coleoptera. In the study conducted in the Municipality of Pucarani, located in the province of Los Andes La Paz Department at 3852 meters between autumn and winter, two copies of pork S. scrofa was obtained in two environments: open (pork A), closed (pig B). 339 specimens between Diptera and Coleoptera were identified. No significant differences were found in the entomofauna sequence between the two environments, however the Fannide sp. In the place closed for being a humid environment. The most important dipterans are: Sarconesia Chlorogaster, Clorobrachycoma splendida, belonging to the family Calliphoridae, which remained in constant activity in its larval stage and its adult form in the four decaying states at temperatures of 14 - 16 ° C, humidity Relative to 30%; Calliphora nigribasis was not found in advanced decomposition; Magellanic sarconesiopsis only occurs in the Fresco stage. Among the Coleoptera: Oxelitrum apicale appeared from the swollen stage. The succession of cadaveric entomofauna and its particularity in each stage of decomposition is the element that would help us determine the MPI, which will depend on high altitude climatic conditions like Bolivia.