Diagnosing death 50 years after the Harvard brain death report

More than 50 years after the publication of the Harvard Committee Report that sought to define death according to whole-brain function criteria, this document continues to generate a diversity of opinions regarding how death should be defined. The various perspectives show that doubts linger regarding when brain death should be diagnosed, the criteria to pinpoint the occurrence of death, and the alignment of medical practices seeking to establish human death with these criteria. This study reviews and assesses three perspectives that have made significant contributions to the debate. Attention is also given to definitions of death that depart from the recommendations of the Harvard Report. Appraisals of various arguments lead to the conclusion that changes in the definition of death have resulted from advances in knowledge of human biology, medical technology and diagnostic techniques. A commentary is included on expediting the time of death with the view of organ donation

Heat shock protein 60 in rostral ventrolateral medulla reduces cardiovascular fatality during endotoxaemia in the rat

The rostral ventrolateral medulla (RVLM) is the origin of a ‘life-and-death’ signal that reflects central cardiovascular regulatory failure during brain stem death. Using an experimental endotoxaemia model, we evaluated the hypothesis that the 60 kDa heat shock protein 60 (HSP60) reduces cardiovascular fatality during brain stem death via an anti-apoptotic action in the RVLM. In Sprague-Dawley rats maintained under propofol anaesthesia, proteomic or Western blot analysis revealed a progressive augmentation of HSP60 expression in the RVLM after intravenous administration of Escherichia coli lipopolysaccharide (30 mg kg(−1)). Pretreatment with a microinjection of actinomycin D or cycloheximide into bilateral RVLM significantly blunted this HSP60 increase, whereas real-time PCR showed progressive augmentation of hsp60 mRNA. Intriguingly, superimposed on the augmented expression was a progressive decline in mitochondrial, or elevation in cytosolic, HSP60 in ventrolateral medulla. Loss-of-function manipulations in the RVLM using anti-HSP60 antiserum or antisense hsp60 oligonucleotide exacerbated mortality by potentiating the cardiovascular depression during experimental endotoxaemia, alongside intensified nucleosomal DNA fragmentation, elevated cytoplasmic histone-associated DNA fragments or augmented cytochrome c–caspase-3 cascade of apoptotic signalling in the RVLM. Immunoprecipitation coupled with immunoblot analysis further revealed a progressive increase in the complex formed between HSP60 and mitochondrial or cytosolic Bax or mitochondrial Bcl-2 during endotoxaemia, alongside a dissociation of the cytosolic HSP60–Bcl-2 complex. We conclude that HSP60 redistributed from mitochondrion to cytosol in the RVLM confers neuroprotection against fatal cardiovascular depression during endotoxaemia via reduced activation of the cytochrome c–caspase-3 cascade of apoptotic signalling through enhanced interactions with mitochondrial or cytosolic Bax or Bcl-2