A new way of measuring apoptosis by absolute quantitation of inter-nucleosomally fragmented genomic DNA.

Several critical events of apoptosis occur in the cell nucleus, including inter-nucleosomal DNA fragmentation (apoptotic DNA) and eventual chromatin condensation. The generation of apoptotic DNA has become a biochemical hallmark of apoptosis because it is a late 'point of no return' step in both the extrinsic (cell-death receptor) and intrinsic (mitochondrial) apoptotic pathways. Despite investigators observing apoptotic DNA and understanding its decisive role as a marker of apoptosis for over 20 years, measuring it has proved elusive. We have integrated ligation-mediated PCR and qPCR to design a new way of measuring apoptosis, termed ApoqPCR, which generates an absolute value for the amount (picogram) of apoptotic DNA per cell population. ApoqPCR's advances over current methods include a 1000-fold linear dynamic range yet sensitivity to distinguish subtle low-level changes, measurement with a 3- to 4-log improvement in sample economy, and capacity for archival or longitudinal studies combined with high-throughput capability. We demonstrate ApoqPCR's utility in both in vitro and in vivo contexts. Considering the fundamental role apoptosis has in vertebrate and invertebrate health, growth and disease, the reliable measurement of apoptotic nucleic acid by ApoqPCR will be of value in cell biology studies in basic and applied science.

Ubisol-Aqua: coenzyme Q10 prevents antiretroviral toxic neuropathy in an in vitro model.

BACKGROUND: Peripheral neuropathy is the dose-limiting toxicity of stavudine and didanosine (nucleoside analogs used in HIV treatment) and is attributed to mitochondrial toxicity from these drugs. Acetyl L-carnitine (ALC) and co-enzyme Q(10) are proposed as neuropathy treatments, but evidence to support these is limited. METHODS: We examined ALC and a water-soluble formulation of co-enzyme Q(10) (H(Q)O) for the prevention of d4T and ddI neurotoxicity using cultured fetal rat DRG as an in vitro model. RESULTS: DdI (33microM) and d4T (50microM) caused clear toxicity (impaired neurite growth) by day 8 of DRG culture. H(Q)O at concentrations 1-100microM completely prevented the toxicity of 33microM ddI in vitro and ALC at concentrations 1-100 microM substantially (but incompletely) prevented ddI toxicity in this model. In contrast, ALC was ineffective at all concentrations tested for preventing the toxicity of 50microM d4T. H(Q)O showed dose-dependent efficacy for preventing d4T toxicity. H(Q)O (1microM) partially prevented d4T toxicity while 10 and 100microM H(Q)O completely prevented d4T toxicity in this model. CONCLUSIONS: We find H(Q)O is superior to ALC for preventing the neurotoxicity of d4T (the HIV treatment most associated with neuropathy) and ddI in vitro. Further study is needed to clarify any clinical role for co-enzyme Q(10) co-administration with d4T and ddI and to assess whether this compound may have a role in treating established cases of neuropathy.