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Depression is a risk factor for dementia in general, including Alzheimer's disease (AD), its premorbid signs are commonly observed, and the morbidity of depression is higher in dementia patients. Dementia with Lewy bodies (DLB) is considered to have an even higher depression prevalence and premorbid depression rate than other dementias such as AD. This led to depression being listed as a supportive feature in the 2005 criteria for the clinical diagnosis of DLB. However, studies investigating the difference in depression between AD and DLB failed to show consistent results. We examined the Geriatric Depression Scale score, which is designed specifically to rate depression in the elderly, for DLB and AD patients. The scores for DLB patients were twice as high as those for AD patients. There was no correlation between the GDS score and age, sex, or Mini-Mental Sate Examination scores. Depression-specific symptoms were more frequent in the DLB group than non-specific symptoms, while less than one third of DLB patients with very high GDS scores were diagnosed with depression or prescribed antidepressants for depressive symptoms. Other researchers reported that depression of DLB was associated with a higher prevalence of psychiatric symptoms other than major depression, and suggested that depression of DLB might be a part of psychiatric syndrome. There has been no systematic study on the validity or risk of pharmacological therapy, as well as the necessity of intervention, for depression or a high GDS score in DLB. Therefore, intervention must rely on the clinical decision of each doctor. In spite of the paucity of current findings, studies on depression of DLB may play a key role in the elucidation of its neuropathology and psychopathology and offer a new view point on understanding depression itself.

Main concepts and principles of radiation protection system are reviewed. Especially, the concept of LNT model and its background are discussed. Also, the major principles, i.e., (i) justification, (ii) optimization, and (iii) the application of dose limits, are reviewed with emphasis on the existing situation, which is mostly related to the current situation in Fukushima.

"Hormesis" is defined, originally in the field of toxicology, as a phenomenon in which a harmful substance gives stimulating effects to living organisms when the quantity is small. The concept was extended and applied to ionizing radiation, high doses of which are harmful. Although radiation has been thought to be, based on findings in high dose ranges, harmful no matter low the dose is, recent investigation revealed that living organisms possess the ability to respond to low-dose radiation in very sophisticated ways. A good example of such responses is the so-called radiation adaptive response, a process in which acquired radioresistance is induced by low-dose radiation given in advance. The stimulation of certain bioprotective functions, including antioxidative capacity, DNA repair functions, apoptosis, and immune functions are thought to underly the adaptive response. The adaptive response is effective for chromosome induction, acute death, and tumorigenesis induced by high doses of radiation. Radiation hormesis and adaptive response provide a new scope in the risk assessment and medical application of ionizing radiation.

Thrombotic thrombocytopenic purpura(TTP) is a multisystem disorders characterized by thrombocytopenia, microangiopathic hemolytic anemia associated with red cell fragmentation, and neurological and renal symptoms. Plasma of patients with TTP has been shown to contain unusually large von Willebrand factor(vWF) multimers that may cause platelet agglutination in vivo. Recently, a metalloprotease responsible for cleavage of vWF multimers has been isolated from normal human plasma and was found to be deficient in some patients with TTP. We examined the activity of the vWF-cleaving protease(vWF-CP), by modified Furlan's method, in plasma from patients with a familial TTP, 3 acquired TTP, 4 thrombotic microangiopathy(TMA) and 2 veno-occlusive disease(VOD) associated after allo-BMT. Diluted plasma samples of patients were incubated with protease-free vWF purified from normal human plasma, in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in SDS-agarose gels and immunoblotting. Activity of vWF-CP from 12 normal plasma have been shown as 77-180%(average 115%), whereas, no vWF-CP(below 5%) was observed in plasma from familial TTP, before and after plasma exchange, although FFP infusion therapy has been effective for this patient to recover thrombocytopenia. In 3 acquired TTP, 2 patients showed lack of vWF-CP activity in plasma, and inhibitors against vWF-CP have been elucidated by plasma cross-mixing test. After extensive plasma exchange and FFP infusion followed by corticosteroid therapy, normal vWF-CP was recovered in plasma from 2 acquired TTP patients. Among BMT patients, plasma from 4 BMT-TMA showed normal vWF-CP activities as 55-111%, whereas plasma from 2 BMT-VOD revealed low vWF-CP activity, as 24% and 37%, respectively. Thus, measurement of vWF-CP is crucial to predict differentiation of primary forms of TMA to establish the pathogenesis in varied endothelial dysfunction.

Oxidative stress is known to be related to various diseases such as inflammation, carcinogenesis, arteriosclerosis and ischemia-reperfusion injury, and is also a major cause of aging. For the prevention of diseases and control of aging, evaluation and control of oxidative stress in vivo may become essential. We have developed the new Oxidative Stress Profile(OSP), a total diagnostic system which provides information about oxidative stress inside human body. The OSP system consists of a number of biomakers including oxidative damage markers, prooxidant factors, antioxidants and life style-related markers. The result is shown in a two dimensional plot form. We measured a combination of biomarkers for oxidative damage of biological components, serum antioxidants and analyzed oxidative stress. The result show that oxidative stress was elevated in diabetic patients in comparison with normal controls. Oxidative stress is also elevated in smokers in comparison with non-smokers. It is also interesting to find that oxidative stress can be greatly reduced by the improvement of life style such as diet. Oxidative Stress Profile system may become a powerful tool for the evaluation of oxidative stress in vivo, and may be useful in prevention of diseases, "mi-byo"(possible cause of diseases)-diagnosis and the control of aging.