RIG-I-like receptor-induced IRF3 mediated pathway of apoptosis (RIPA): a new antiviral pathway

The innate immune response is the first line of host defense to eliminate viral infection. Pattern recognition receptors in the cytosol, such as RIG-I-like receptors (RLR) and Nod-like receptors (NLR), and membrane bound Toll like receptors (TLR) detect viral infection and initiate transcription of a cohort of antiviral genes, including interferon (IFN) and interferon stimulated genes (ISGs), which ultimately block viral replication. Another mechanism to reduce viral spread is through RIPA, the RLR-induced IRF3-mediated pathway of apoptosis, which causes infected cells to undergo premature death. The transcription factor IRF3 can mediate cellular antiviral responses by both inducing antiviral genes and triggering apoptosis through the activation of RIPA. The mechanism of IRF3 activation in RIPA is distinct from that of transcriptional activation; it requires linear polyubiquitination of specific lysine residues of IRF3. Using RIPA-active, but transcriptionally inactive, IRF3 mutants, it was shown that RIPA can prevent viral replication and pathogenesis in mice.

Skull fracture and haemorrhage pattern among fatal and nonfatal head injury assault victims - a critical analysis

The global incidence of fatal head injuries as the result of assault is greater than the number of non-fatal cases. The important factors that determine the outcome in terms of survival of such head injury cases include the type of weapon used, type and site of skull fracture, intra cranial hemorrhage and the brain injury. The present study aims to highlight the role of skull fractures as an indirect indicator of force of impact and the intra cranial hemorrhage by a comparative study of assault victims with fatal and nonfatal head injuries. 91 head injury cases resulting from assault were studied in the Department of Forensic Medicine, IMS, BHU Varanasi over a period of 2 years from which 18 patients survived and 73 cases had a lethal outcome. Details of the fatal cases were obtained from the police inquest and an autopsy while examination of the surviving patients was done after obtaining an informed consent. The data so obtained were analyzed and presented in the study. Assault with firearms often led to fatality whereas with assault involving blunt weapons the survival rate was higher. Multiple cranial bones were involved in 69.3% cases while comminuted fracture of the skull was common among the fatal cases. Fracture of the base of the skull was noted only in the fatal cases and a combination of subdural and subarachnoid hemorrhage was found in the majority of the fatal cases. The present study shows skull fractures to be an important indicator of severity of trauma in attacks to the head. Multiple bone fracture, comminuted fracture and base fractures may be considered as high risk factors in attempted homicide cases