The descriptive epidemiology of cancer in the Asian Pacific region of the world is now well-established due to the activities of cancer registries. Major differences in the most prevalent cancers continue to be observed, both within and between individual countries, gastric cancer being a prime example with high incidences in Japan, China and Korea but very low burdens in Thailand and Indonesia. Hepatocellular carcinomas are particularly prevalent in Mongolia while cancers of the oral cavity predominate in South Asia and are also relatively common in Taiwan, with a common link to betel chewing. Both ethnicity and specific dietary habits retain importance, for example with nasopharyngeal cancer in southern Chinese and cholangiocarcinoma in the north-east of Thailand. However, there are consistent trends affecting all countries, and cancer of the lung in males and lung and breast in females appear to be on the increase across the region. Of particular concern is the increase in adenocarcinoma of the female lung in non-smokers. Regarding mortality, there is major variation depending on the facilities available, level of awareness and socioeconomic background. For risk and beneficial factor analysis, great advances have recently been made due to the establishment of the Hospital-Based Epidemiologic Research Program at Aichi Cancer Center (HERPACC) and the Korean Multi-center Cancer Cohort Study including a Biological Materials Bank (KMCC-I). These are providing valuable clues as to potential preventive measures, generally in line with the literature for other regions of the globe. Included in HERPACC is a comprehensive approach to analysis of gene-environment interactions and influence of polymorphisms. The future should see greater emphasis on education and practical efforts by epidemiologists across the Asian Pacific to counter the growing threat of cancers due to tobacco smoking and the change to a high fat western diet. In addition to the focus on diet and physical exercise as preventive agents, for example now being tested for efficacy in the colon, further development of primary prevention approaches focusing on vaccines and chemopreventive agents await clinical trials.

(Communicated by Takashi SUGIMURA, M. J. A., Feb. 12, 2003)

抄録全体を表示

To capture the potentially enormous and vital opportunity in the post sequence era of human genome research, the Japanese government on December 19, 1999 drew up the basic outlines of the 5-year Millennium Genome Project (MGP). The “Disease Gene” Team of MGP aims to establish genome-based personalized medical care and to seed a revolutionary drug development inspired by the new information and technology, which the genome research provides. Five disease categories have been chosen as project targets: dementia, cancer, diabetes, hypertension and asthma, which are manifesting a major impact on the health and welfare of the rapidly graying Japanese society. These so-called “common diseases” are etiologically multifactorial, and the genetic components, if any, are considered polygenic with relatively high disease allele frequencies in the population. In the first year, 2000, a consortium or “Subteam” was established for each disease category, and several hypothesis-driven candidate gene approaches were launched. In 2001, a complementary strategy of disease gene hunting, a statistics-based genome-wide approach, was initiated. The Disease Gene Team decided to employ a genome-wide, gene-based SNP scan through close collaboration with another arm of MGP, the “Human Genome Variation” Team, which discovered 194, 393 SNPs as of December 25, 2002 from genome of the Japanese people. Each Subteam reached a consensus regarding eligibility criteria and research protocols, which were reviewed by the institutional review boards in accordance with the new Ethics Guidelines For Human Genome/Genetic Analysis Research promulgated by the government on April 1, 2001. The Subteams organized a multi-institutional consortium, which in 2001 collaborated in the collection of quality germline DNA samples and clinical and life-style related information. In 2002, the third year of MGP, the genome scan started at two typing centers using the high-throughput SNP typing system established by RIKEN. The premise and prospect of the approach will be discussed.

(Communicated by Takashi SUGIMURA, M. J. A., Feb. 12, 2003)

抄録全体を表示

Off Urakawa, Hokkaido district landward of a junction of Chishima trench and Japan trench, there is a large negative gravity anomaly of about 200 mgals. Off Miyazaki, Kyushu district landward of a junction of Ryukyu trench and Nankai trough, there is also large negative gravity anomaly.
If the oceanic plate uniformly moves, an excess mass is produced at the trench junction and the excess mass should be observed as a positive gravity anomaly. However, on the contrary, large negative anomaly is actually observed. The idea presented in this paper is that, the excess mass falls in the mantle, and this causes a depression of earth surface (free surface), and lack of mass at the surface produces negative free air gravity anomaly.
The problems of surface deformation due to falling ball which is rigid and denser than the surround viscous material, were discussed by Morgan in 1965, ^{1), 2)} and excellent papers were published. The deformations of the surface due to a rigid falling ball are divided into two parts. The one is due to direct attraction of the ball and gravity does not change though the surface sink in. The other is due to a current within the viscous fluid and the surface sink in and gravity changes. The amount of the change in gravity is roughly twice as large as gravity due to descending ball, with opposite sign.
The water contained in sediment on the ocean floor is transported to a deeper part of the mantle by a descending plate. The water is released into a mantle of continent at the depth of about 150 km and, lowers melting temperature there and negative buoyancy of the plate changes to buoyancy. Therefore the depth is a limit of negative buoyancy of the plate. According to the idea, the excess mass at trench junction off Urakawa and off Miyazaki were estimated and tried to explain origin of negative gravity anomaly landward of trench junction.

(Contributed by Yoshibumi TOMODA, M. J. A., Feb. 12, 2003)

抄録全体を表示

A new synthesis method for the silica-gel activator involving the hydrolysis of silicic acid ester was examined. Tetraethoxysilane (TEOS) was used as silicic acid ester. The silica-gel was obtained in mixed solvents of water (6.415 ml) and ethanol (0.230 ml) by hydrolysis of 0.230 ml of TEOS, using 0.125 ml of ammonia solution (20 wt.%) as a catalyst.
An ion beam current (²⁰⁸Pb) of 4.0×10^-11 A or more can be obtained with 200 ng of lead samples (NIST SRM 981) using our new synthesized silica-gel activator. Moreover, the ion beam current decayed less than 40% over the course of about 30 min. No significant change of isotopic composition was observed within a single run. The uncertainties for the ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁶Pb/²⁰⁴Pb ratios of NIST SRM 981 (100-200 ng) over 16 separate experiments were 0.027%, 0.020% and 0.015% (1σ%), respectively.
These observations suggest that the silica-gel synthesized from silicic acid ester can be applied to the lead isotope analyses. It is well known that the size, size distribution and specific surface of silica can be controlled during the synthesizing silica-gel from silicic acid ester. Therefore, the present research makes it possible to investigate the relation between the capability of silica-gel as an activator for the lead isotope analyses, and the physicochemical properties of the silica-gel.

(Communicated by Ikuo KUSHIRO, M. J. A., Feb. 12, 2003)

抄録全体を表示

We have crystallized the protein pot0434017 from the archaeon Pyrococcus sp. OT3. In the crystals dimers of this protein are arranged into helical cylinders, continuing through the crystals by crossing over asymmetric units; 6 sets of dimers forming each helical turn. While, formation of disks in crystals by 4 sets of dimers was reported for similar proteins (pot1216151 from P. OT3 and LrpA from Pyrococcus furiosus). These archaeal proteins and E. coli transcription factors, Lrp (leucine-responsible regulatory protein) and AsnC (aspargine synthesis C gene product), together with a large number of other archaeal and eubacterial proteins, form a large protein family; for which the classification feast/famine regulatory proteins (FFRPs) is proposed. On the basis of an analysis of the assembly forms of FFRPs, and on the basis of identification of numbers and types of ffrp genes coded in various bacterial genomes, possible biological roles of FFRPs are discussed.

(Communicated by Masanori OTSUKA, M. J. A., Feb. 12, 2003)

抄録全体を表示