Spontaneous well-differentiated pancreatic islet cell carcinoma with vascular invasion in a male F344 rat     

Shiori Fujiwara  Yuko Yamaguchi  Tsubasa Saito  Tomomi Nakazawa  Kazutoshi Tamura 《Journal of toxicologic pathology》2022,35(1):99

This case report describes a case of spontaneous pancreatic islet cell carcinoma with vascular invasion in a 110-week-old male F344 rat. Histologically, a pancreatic nodule consisting of tumor cells and many blood-rich vessels, and covered with a fibrous capsule showed local invasion in the capsule and adjacent acinar tissues, encircling a large duct-like structure (DS). The tumor was composed of well-differentiated tumor cells resembling normal pancreatic islet cells, which had small round nuclei and eosinophilic cytoplasm. Mitotic figures were rare. Immunohistochemistry revealed that the tumor cells were positive for insulin. Although endothelial cells were not detected, the DS wall showed cells positive for α-smooth muscle actin and elastic fibers, suggesting that the DS is the pancreatic artery. This is a rare case of islet cell carcinoma consisting of well-differentiated tumor cells with invasion of the pancreatic artery in a rat.  相似文献   

Recreational fishery as a conservation tool for endemic Dolly Varden <Emphasis Type="Italic">Salvelinus malma miyabei</Emphasis> in Lake Shikaribetsu,Japan     

Taku Yoshiyama  Jun-ichi Tsuboi  Takashi Matsuishi 《Fisheries Science》2017,83(2):171-180

Recreational angling is a popular leisure activity globally and can be a threat or useful conservation tool depending on the management strategy. Miyabe charr Salvelinus malma miyabei is an endemic fish that inhabits Lake Shikaribetsu, and a management program was established to harmonise recreational fishery and conservation. To examine the suitability of this program, population assessment was conducted with the cooperation of anglers. The population size in 2014 as assessed by tag-and-release angling was estimated to be 105,300 [95% confidence interval (CI) 37,300–178,600], much higher than the reported estimate in 1995. Further, angling mortality was estimated to be quite low. Moreover, no decreasing population trend was detected on analysing 8 years of anglers’ catch data. Consequently, angling has facilitated stock assessments of Miyabe charr under the current program. This case is a good example of recreational angling acting as a conservation tool under appropriate management.  相似文献   

Reproductive season and female maturity size of coconut crab <Emphasis Type="Italic">Birgus latro</Emphasis> on Hatoma Island,southern Japan     

Taku Sato  Kenzo Yoseda 《Fisheries Science》2008,74(6):1277-1282

Information about reproductive season, size at sexual maturity and size-dependent reproductive potentials is important for efficient resource management. Such information is necessary to determine seasonal closures and minimum legal size limits. To conserve resources of coconut crab Birgus latro, which are in danger of extinction due to excessive exploitation, their reproductive season, female size at functional maturity and relationship between female size and reproductive potentials were investigated. The reproductive season started in early June and ended late August, and females with higher reproductive potentials showed a tendency to spawn early in the reproductive season. The prohibition of exploiting the resources during the reproductive season, especially early in the season, would be appropriate for sustainability of high reproductive outputs. Fifty percent of investigated females matured functionally at 24.5-mm thoracic length (TL). However, the size at which all females reached functional maturity was 32.3 mm TL, and there was a wide variation in the size of functional maturity among individuals. We must determine minimum legal size by taking the variation into account to allow all individuals to mate at least once before they are caught, which may prevent serious depression in reproductive rate and genetic diversity.  相似文献   

Cadmium transport and tolerance in rice: perspectives for reducing grain cadmium accumulation   总被引：10，自引：0，他引：10  

Shimpei Uraguchi  Toru Fujiwara 《Rice》2011,5(1):1-8

In recent decades, numerous studies have attempted to project the impact of hypothesised anthropogenic climate change on rice production. In this study, we offer a comprehensive review of our current understanding related to temperature, CO₂, and water-demand parameters in rice growth models. As to future rice yield, night time temperature should be focused in the models as well as day time temperature owing to the contribution of temperature on the night time respiration. Furthermore, although CO₂-enhanced photosynthesis is critical for the accurate prediction of rice production in a higher CO₂ atmosphere, we found that recent well-developed photosynthesis-stomatal model cannot realize the variation of CO₂ stomatal sensitivity with humidity conditions. To estimate water stress under projected climate-change conditions, rice growth model should be required to link with water resource model, which includes natural processes and anthropogenic regulations. The understanding of abilities and limitations in the models is important not only to improve the schemes that models employ, but to also critically review the simulated results.  相似文献   

Improvement in recruitment of Japanese sardine with delays of the spring phytoplankton bloom in the Sea of Japan          下载免费PDF全文

Taketoshi Kodama  Taku Wagawa  Seiji Ohshimo  Haruyuki Morimoto  Naoki Iguchi  Ken‐Ichi Fukudome  Tsuneo Goto  Motomitsu Takahashi  Tohya Yasuda 《Fisheries Oceanography》2018,27(4):289-301

To evaluate the impact of temporal variation of primary productivity on the recruitment of Japanese sardine (Sardinops melanostictus) in the Sea of Japan, the phenology of sea surface phytoplankton abundance was estimated from 8 day multiple satellite (SeaWiFS, MODIS‐Aqua, MERIS, and VIIRS) derived sea surface chlorophyll (SSChl) a concentrations from January 1998 to December 2015. Because relationships between SSChl a and in situ chlorophyll a concentrations were significantly different among periods based on the satellite combinations used, maximum and minimum SSChl a concentrations of 1 year were relativized as 1 and 0, respectively. Spatio‐temporal variation of relativized SSChl a concentrations was determined by using empirical orthogonal function (EOF) analysis. Scores in the first EOF mode denoted the basin‐scale variations of SSChl a concentrations in the Sea of Japan, and the major peak from the end of February to the end of May displayed the spring bloom. The logarithm of recruitment per spawner (LNRPS) for sardine was positively affected by delays in the start and end dates of the spring phytoplankton bloom. The delay of the date of the lowest sea surface temperature contributed to the delay of the end of the spring bloom during the period 1998–2015 and elevated the LNRPS during the period 1982–2015. Sardine spawns in the southern Sea of Japan from April to May, hence, delays of the spring bloom prolonged its overlap with sardine larval periods, and thus improved the recruitment of Japanese sardine in the Sea of Japan.  相似文献   

Pelvic fin removal modifies escape trajectory in a teleost fish     

Yuuki Kawabata  Hideaki Yamada  Taku Sato  Masato Kobayashi  Koichi Okuzawa  Kimio Asami 《Fisheries Science》2016,82(1):85-93

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Nephroblastoma with liver and lung metastases in an adult dog     

H Nakayama  T Hayashi  R Takahashi  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1984,46(6):897-900

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Pathological observations of feline mast cell tumor   总被引：1，自引：0，他引：1  

N Goto  M Ozasa  R Takahashi  K Ishida  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1974,36(6):483-494

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Induction of autoimmune tubulo-interstitial nephritis in guinea pigs immunized with the canine renal basement membranes     

K Shirota  K Fujiwara 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1985,47(6):1018-1021

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The effects of within-species and between-species variation in wood density on the photodegradation depth profiles of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa)     

Yutaka Kataoka  Makoto Kiguchi  Takeshi Fujiwara  Philip D. Evans 《Journal of Wood Science》2005,51(5):531-536

Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight emitted by a xenon lamp (375 W/m² within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation. The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally, why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural weathering. Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004  相似文献