Recent aspects of uranium toxicology in medical geology

Uranium (U) is a chemo-toxic, radiotoxic and even a carcinogenic element. Due to its radioactivity, the effects of U on humans health have been extensively investigated. Prolonged U exposure may cause kidney disease and cancer. The geological distribution of U radionuclides is still a great concern for human health. Uranium in groundwater, frequently used as drinking water, and general environmental pollution with U raise concerns about the potential public health problem in several areas of Asia. The particular paleo-geological hallmark of India and other Southern Asiatic regions enhances the risk of U pollution in rural and urban communities. This paper highlights different health and environmental aspects of U as well as uptake and intake. It discusses levels of U in soil and water and the related health issues. Also described are different issues of U pollution, such as U and fertilizers, occupational exposure in miners, use and hazards of U in weapons (depleted U), U and plutonium as catalysts in the reaction between DNA and H₂O_2, and recycling of U from groundwater to surface soils in irrigation. For use in medical geology and U research, large databases and data warehouses are currently available in Europe and the United States.

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.

Should autism be considered a canary bird telling that Homo sapiens may be on its way to extinction?

There has been a dramatic enhancement of the reported incidence of autism in different parts of the world over the last 30 years. This can apparently not be explained only as a result of improved diagnosis and reporting, but may also reflect a real change. The causes of this change are unknown, but if we shall follow T.C. Chamberlin's principle of multiple working hypotheses, we need to take into consideration the possibility that it partly may reflect an enhancement of the average frequency of responsible alleles in large populations. If this hypothesis is correct, it means that the average germline mutation rate must now be much higher in the populations concerned, compared with the natural mutation rate in hominid ancestors before the agricultural and industrial revolutions. This is compatible with the high prevalence of impaired human semen quality in several countries and also with what is known about high levels of total exposure to several different unnatural chemical mutagens, plus some natural ones at unnaturally high levels. Moreover, dietary deficiency conditions that may lead to enhancement of mutation rates are also very widespread, affecting billions of people. However, the natural mutation rate in hominids has been found to be so high that there is apparently no tolerance for further enhancement of the germline mutation rate before the Eigen error threshold will be exceeded and our species will go extinct because of mutational meltdown. This threat, if real, should be considered far more serious than any disease causing the death only of individual patients. It should therefore be considered the first and highest priority of the best biomedical scientists in the world, of research-funding agencies and of all medical doctors to try to stop the express train carrying all humankind as passengers on board before it arrives at the end station of our civilization.

Drug-related mortality: methods and trends

Drug-related deaths attract widespread concern and public interest and this is reflected in the number of queries ONS receives on this topic. This article sets out the processes involved in the collection and compilation of data on drug-related deaths in England and Wales to serve as a point of reference for users of ONS mortality data. It also documents recent trends in drug-related deaths, revealing considerable variation in mortality by age, sex and region.

Mortality during the 1996/7 winter

There was a sharp peak in mortality during the 1996/7 winter, resulting in an estimated 49 thousand excess deaths. This article describes the timing of the winter peak, the population affected and the main causes of death. The relationship between excess winter mortality, temperature and influenza is also explored. The peak in the number of deaths in December 1996 and January 1997 coincided with a peak in the number of deaths attributed to influenza and with low temperatures. However, the excess winter mortality was higher than expected, based on the experience of previous winters.

[Milk and health]

BACKGROUND

Milk has been an important part of Norwegian nutrition for generations. The article is a review of literature concerning research on milk and health.

MATERIAL AND METHODS

Relevant literature with results that were confirmed by others were chosen from acknowledged journals from Pubmed in the period 1977-2006, by using the search words milk, fat, atherosclerosis, omega-3, omega-6, cancer, allergy, trace elements, iodine and selenium.

RESULTS AND INTERPRETATION

Milk and milk products contain many essential nutrients. The content of oleic acid, conjugated linoleic acid, omega-3 fatty acids, short- and medium chain fatty acids, vitamins, minerals and bioactive compounds may promote positive health effects. Certain studies indicate that a moderate intake of milk fat reduces the risk of cardiovascular disease, possibly through reduced formation of small dense LDL-particles, despite of its inherent tendency to increase total cholesterol. For individuals with genetic metabolic defects, milk proteins, fat and milk sugar may cause health problems. The low pH in fermented milk and the formation of substances during the fermentation process may have a beneficial effect. Full-fat milk and fermented milk lead to delayed gastric emptying, and thereby to reduced glycaemia and reduced appetite. Harmful substances may be formed when proteins react with sugar, especially at a high temperature; a fact that should be considered with an increasing use of sweetened milk products. The cow's diet affects the milk's content of many nutrients as for example fatty acids, iodine and selenium. The composition of milk for commercial use should be investigated.