The Spanish flu as a worst case scenario?

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Geography may explain adult mortality from the 1918-20 influenza pandemic

Seasonal influenza takes its most pronounced toll on children and the elderly, giving the crude age-specific mortality rates a U-shape. In contrast, A(H1N1) 1918-20 pandemic mortality was W-shaped. When adjusting for the seasonal baseline, young adults had higher but the elderly lower than expected mortality. The lower than expected mortality for the elderly is one reason why total mortality in urban societies were relatively low in 1918-20 (<1%). Why mortality peaked at age 30 but declined into old age is still not clear. It has been suggested that cohorts >30 years was protected because they were exposed to H1-like viruses prior to 1889. This hypothesis assumes that people lived within the reach of the urban disease pools. Here I analyze mortality after age 30 in aboriginal populations assumed to be infrequently exposed to influenza due to their geographic isolation. Results show that Arctic and Pacific peoples also experienced a decline in relative mortality after age 30. However, the remotely living elderly did not have lower than expected mortality, suggesting that they had less prior exposure to influenza than their urban counterpart. Crude total mortality and mortality for all adults >30 years was nevertheless extremely high in the remote populations. Parish records quantitatively confirmed the anecdotes that children 5-14 years were the only survivors in some Arctic communities. Low exposure to H1-like viruses in adults could not alone explain the high total mortality in remote populations (up to 90%). A high concurrent disease load, crowding, low genetic variability, a lack of basic care, and infrequent exposure to other forms of influenza virus 1890-1917 may have played a role as well. This form of immunological cross-protection from previous exposure to A-type influenza viruses other than H1N1 can only be explained as a consequence of cellular immunity against internal proteins that show less inter-strain variation than the surface proteins.