Human thanatomicrobiome studies have established that an abundant number of putrefactive bacteria within internal organs of decaying bodies are obligate anaerobes, Clostridium spp. These microorganisms have been implicated as etiological agents in potentially life-threatening infections; notwithstanding, the scale and trajectory of these microbes after death have not been elucidated. We performed phylogenetic surveys of thanatomicrobiome signatures of cadavers’ internal organs to compare the microbial diversity between the 16S rRNA gene V4 hypervariable region and V3-4 conjoined regions from livers and spleens of 45 cadavers undergoing forensic microbiological studies. Phylogenetic analyses of 16S rRNA gene sequences revealed that the V4 region had a significantly higher mean Chao1 richness within the total microbiome data. Permutational multivariate analysis of variance statistical tests, based on unweighted UniFrac distances, demonstrated that taxa compositions were significantly different between V4 and V3-4 hypervariable regions (p < 0.001). Of note, we present the first study, using the largest cohort of criminal cases to date, that two hypervariable regions show discriminatory power for human postmortem microbial diversity. In conclusion, here we propose the impact of hypervariable region selection for the 16S rRNA gene in differentiating thanatomicrobiomic profiles to provide empirical data to explain a unique concept, the Postmortem Clostridium Effect.

BackgroundC1q represents the initiating protein of the classical complement cascade, however recent findings indicate pathway independent roles such as developmental pruning of retinal ganglion cell (RGC) axons. Furthermore, chronic neuroinflammation, including increased expression of C1q and activation of microglia and astrocytes, appears to be a common finding among many neurodegenerative disease models. Here we compare the effects of a retinal ischemia/reperfusion (I/R) injury on glial activation and neurodegeneration in wild type (WT) and C1qa-deficient mice in the retina and superior colliculus (SC). Retinal I/R was induced in mice through elevation of intraocular pressure to 120 mmHg for 60 min followed by reperfusion. Glial cell activation and population changes were assessed using immunofluorescence. Neuroprotection was determined using histological measurements of retinal layer thickness, RGC counts, and visual function by flash electroretinography (ERG).ResultsRetinal I/R injury significantly upregulated C1q expression in the retina as early as 72 h and within 7 days in the superficial SC, and was sustained as long as 28 days. Accompanying increased C1q expression was activation of microglia and astrocytes as well as a significantly increased glial population density observed in the retina and SC. Microglial activation and changes in density were completely ablated in C1qa-deficient mice, interestingly however there was no effect on astrocytes. Furthermore, loss of C1qa significantly rescued I/R-induced loss of RGCs and protected against retinal layer thinning in comparison to WT mice. ERG assessment revealed early preservation of b-wave amplitude deficits from retinal I/R injury due to C1qa-deficiency that was lost by day 28.ConclusionsOur results for the first time demonstrate the spatiotemporal changes in the neuroinflammatory response following retinal I/R injury at both local and distal sites of injury. In addition, we have shown a role for C1q as a primary mediator of microglial activation and pathological damage. This suggests developmental mechanisms of C1q may be re-engaged during injury response, modulation of which may be beneficial for neuroprotection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13024-016-0089-0) contains supplementary material, which is available to authorized users.

Estrogen is known to produce changes in cardiac electrophysiology specifically in premenopausal women, increasing the risk of arrhythmias. We report a case of Torsades de Pointes (TdP) in a young premenopausal female. A 25-year-old female with a history of anxiety presented to the emergency room (ED) with several days of vomiting. While in the ED, she had an unwitnessed syncopal event, and was found to be in pulseless ventricular fibrillation (V-Fib) . She required one defibrillation to obtain return of spontaneous circulation (ROSC). Initial work up showed calcium 7.6 mg/dl, phosphorous 1.1 mg/dl, magnesium 2.4 mg/dl, potassium 4.0 mg/dl. Remainder of electrolytes were normal. Toxicology screen was positive for cannabinoids. Post ROSC EKG showed sinus tachycardia at a rate of 103bpm with a prolonged QTc of 531ms. Patient was not on any medications outpatient. On further discussion, patient reported no prior history of syncopal episodes, palpitations, and denied any family history of sudden cardiac death. She did report she was presently on her menses. Shortly after admission, she had recurrent polymorphic ventricular tachycardia which degenerated to TdP. She was loaded with magnesium. Echocardiogram showed an ejection fraction (EF) of 35-39% and global hypokinesis. Diagnostic left heart catheterization was performed revealing clean coronaries. Cardiac MRI revealed EF of 43% without any late gadolinium enhancement. Her QTc remained prolonged even with electrolyte normalization. She underwent successful ICD placement and remained event free during the remainder of the hospital course. She will undergo genetic work up for long QT syndrome. Female sex hormones, specifically estrogen, have been described in literature as pro-arrhythmic given its effects on QT prolongation and ion gated channels. Prior cases of menstruation dependent arrhythmias have speculated that the abrupt reduction in estradiol prior to menstruation is associated with increased cyclic adenosine monophosphate dependent arrhythmogenicity. This case highlights the multifactorial etiology of sudden V-Fib arrest in a young female, and the importance of understanding the role that sex hormones play in the underlying pathogenesis.