Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society.

(Communicated by Kiyoshi HORIKAWA, M.J.A.)

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Through glycosphingolipid biochemical research, we developed two types of transcription technologies. One is a biochemical transfer of glycosphingolipids to peptides. The other is a physicochemical transfer of glycosphingolipids in silica gel to the surface of a plastic membrane. Using the first technology, we could prepare peptides which mimic the shapes of glycosphingolipid molecules by biopanning with a phage-displayed peptide library and anti-glycosphingolipid antibodies as templates. The peptides thus obtained showed biological properties and functions similar to those of the original glycosphingolipids, such as lectin binding, glycosidase modulation, inhibition of tumor metastasis and immune response against the original antigen glycosphingolipid, and we named them glyco-replica peptides. The results showed that the newly prepared peptides could be used effectively as a bio-recognition system and suggest that the glyco-replica peptides can be widely applied to therapeutic fields. Using the second technology, we could establish a functional lipidomics with a thin-layer chromatography-blot/matrix-assisted laser desorption ionization-time of flight mass spectrometry (TLC-Blot/MALDI-TOF MS) system. By transferring glycosphingolipids on a plastic membrane surface from a TLC plate, innovative biochemical approaches such as simple purification of individual glycosphingolipids, binding studies, and enzyme reactions could be developed. The combinations of these biochemical approaches and MALDI-TOF MS on the plastic membrane could provide new strategies for glycosphingolipid science and the field of lipidomics. In this review, typical applications of these two transfer technologies are introduced.

(Communicated by Kunihiko SUZUKI, M.J.A.)

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The conversion of what has been interpreted as “normal brain aging” to Alzheimer’s disease (AD) via transition states, i.e., preclinical AD and mild cognitive impairment, appears to be a continuous process caused primarily by aging-dependent accumulation of amyloid β peptide (Aβ) in the brain. This notion however gives us a hope that, by manipulating the Aβ levels in the brain, we may be able not only to prevent and cure the disease but also to partially control some very significant aspects of brain aging. Aβ is constantly produced from its precursor and immediately catabolized under normal conditions, whereas dysmetabolism of Aβ seems to lead to pathological deposition upon aging. We have focused our attention on elucidation of the unresolved mechanism of Aβ catabolism in the brain. In this review, I describe a new approach to prevent AD development by reducing Aβ burdens in aging brains through up-regulation of the catabolic mechanism involving neprilysin that can degrade both monomeric and oligomeric forms of Aβ. The strategy of combining presymptomatic diagnosis with preventive medicine seems to be the most pragmatic in both medical and socioeconomical terms.

(Communicated by Kunihiko SUZUKI, M.J.A.)

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Using ovariectomized rats as a model of postmenopausal women, we studied the effects of estrogen (Es) deficiency and in combination with cadmium (Cd) exposure on the calcified hard tissues related to the development of itai-itai disease. Es deficiency suppressed the synthesis of carbonic anhydrase required for the crystal nucleation process, causing the crystal structure defects in the tooth enamel. Regarding the combined effects of Es deficiency and Cd exposure on the bone, in which rats were given drinking water containing Cd ions, soft X-ray radiography revealed a development of labyrinthine pattern in the calvaria, and micro-computed tomography demonstrated the declining trabecular architecture of the tibia, suggesting Cd–induced osteoporotic change. Further, electron microscopy showed the increase of amorphous minerals in the calvaria. In conclusion, the combined effects of Es deficiency and Cd exposure can be responsible for accelerating the declining bone strength together with the crystal structure defects resulting in the preferential occurrence of itai-itai disease in postmenopausal women.

(Communicated by Tatsuo SUDA, M.J.A.)

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