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Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. We previously visualized the PGCs of several teleostean embryos by injecting RNA synthesized from constructs encoding green fluorescent protein (GFP) fused to the 3'UTR of the zebrafish (Danio rerio) nanos1 gene (nos1). However, this technique was not always suitable for visualizing PGCs in embryos from all teleost species. In this study, we compared the visualization of PGCs in common carp (Cyprinus carpio) embryos using two artificial constructs containing GFP fused to the 3'UTR of nanos from either common carp or zebrafish. Visualization was better using GFP fused to the 3'UTR of the nanos gene from common carp, compared with that from zebrafish. The visualized PGCs successfully migrated toward the gonadal ridge after transplantation into goldfish host embryos, suggesting that they maintained normal migratory motility. These techniques could be useful for the production of inter-specific germline chimeras using common carp donor PGCs.

【Objective】The purposes of this study were to classify the lesions of dialysis-associated spondylosis and evaluate the results of surgical treatment. 【Subjects and methods】The subjects were 87 patients (43 men and 44 women) who underwent surgery. These patients were studied in terms of lesion classification, surgical method, duration of dialysis, duration of surgery, intraoperative blood loss, and postoperative complications. 【Results】Among patients with cervical spine involvement, 13 had destructive spondyloarthropathy (DSA), 29 had amyloid deposition, and 8 had a dens axis lesion. Among patients with lumbar spine involvement, 20 had DSA, and 17 had amyloid deposition. With regard to 6 patients with a dens axis lesion involving atlantoaxial subluxation, each had posterior fusion (PF) of the occiput to the upper cervical spine. With regard to the patients with lumbar DSA, 10 patients had posterolateral fusion (PLF), 8 patients had posterior lumbar interbody fusion (PLIF) and 2 patients had laminectomy. The duration of dialysis in cases of a dens axis lesion varied between 25 and 35 years, with the mean duration being 28.9 years. 【Conclusions】All patients who underwent surgery for dens axis lesions were long-term dialysis patients who had been on dialysis for 25 years. Lumbar spine DSA was treated with PLIF in patients with lateral slipping and marked instability, with laminectomy in patients with a narrowed intervertebral disk space and no instability., Acta Medica Nagasakiensia, 56(1), pp.5-11; 2011

The Japanese eel, Anguilla japonica, is one of the most important species of the aquaculture industry of East Asia. Supply of glass eels for aquaculture is completely dependent on wild catch. However, glass-eel catches in Japan declined linearly from over 200 tons in the early 1960s to 20 tons at present. In recent years an unstable situation has occurred with glass-eel catches not meeting the demand of aquaculture farms. In order to address this rapid decline, a challenging research project for artificial production of glass eels was commenced in the late 1960s. Since then, through a continuing process of trial and error, the production of second-generation larvae was finally achieved in 2010. Throughout the research, a new application of several substances has caused breakthroughs in artificial induction of sexual maturation and larvae rearing. This article reports on a study of controlled eel reproduction focusing on the finding of substances that accelerated progress. In addition, guideline research on eel reproduction in the wild was conducted aiming at overcoming current bottlenecks that impeded the establishment of largescale glass-eel production in captivity, by investigating maturing eels and eggs collected in their spawning area in the vicinity of the West Mariana Ridge.

Feminized 2-year-old eels were reared in freshwater at 26℃ until October, then the water temperature was gradually decreased to 16℃ to December, and gradually increased to 26℃ from February to April. They received weekly injections of salmon pituitary extract (body weight, 15 or 30 mg/kg) to induce sexual maturation in September, December, or April. The quality of the eggs obtained in each season was evaluated by the resulting fertilization, hatching, and 8-day survival rates. High quality eggs were obtained via high-dose injections in most experimental groups. In the high-dose injection groups, eels were induced to the final maturation phase in all seasons; however, egg quality obtained in April was extremely low in contrast to that obtained in September and December. Histological observation of oocytes just before the process of artificial maturation was commenced indicated that the developmental stages of oocytes varied by season: oil droplet in September, early vitellogenic in December, and regressive from vitellogenesis in April. The extremely low egg quality in April is probably due to the fact that the oocytes had already entered the regressive stage. These results indicated that better quality of eel eggs can be obtained by starting the process of artificial maturation between September and December., 雌化ウナギ2 歳魚を9 月，12月または4 月にサケ脳下垂体注射によって人為催熟し，得られる卵質の差を受精率，孵化率および8 日後生存率で評価した。9 月，12月は比較的良質な卵が得られる傾向が認められたが，4 月では卵は得られるものの，その卵質は極めて悪かった。催熟前の卵母細胞を組織学的に観察すると，12月に卵黄形成開始が観察されが，4 月には退行している様子が観察された。4 月に催熟を開始しても良質な卵が得られない原因として，催熟前に既に卵母細胞が退行しつつあることが考えられた。以上の結果から，雌化ウナギ2 歳魚の人為催熟は9 月から12月の間にかけて開始することが良質な卵を得るために適当であると結論された。

We are concerned with a quasilinear elliptic equation of the form \begin{equation*} -\Delta u+a(x) u-\Delta(|u|^\alpha)|u|^{\alpha-2}u=h(u)\quad \hbox{in }\mathbb R^N, \end{equation*} where $\alpha> 1$ and $N\geq 1$. By using variational approaches, we prove the existence of at least one positive solution of the above equation under suitable conditions on $a(x)$ and $h$. In particular, we are interested in the situation that $a(x)$ is invariant under the finite group action $G$.

Recently, we succeeded in inducing in vitro spermatogenesis in a protogynous hermaphrodite fish, threespotted wrasse (Halichoeres trimaculatus), during organ culture of ovary with a serum-supplemented medium. In the pres- ent study, we further optimized and used this culture system to determine effective steroid doses to induce sex change, and to investigate the importance of apoptosis during sex change in vitro. The results show that the restructuring from ovary to testis in the wrasse could be induced in vitro with a serum-free medium. Gonadal sex change can be triggered during basic in vitro culture due to a lack of endogenous factors (especially, estrogens) for female sexuality, and can be accelerated by androgens. Furthermore, oocyte apoptosis may be an important mechanism effecting gonadal sex change.

Accumulation of oil droplets in previtellogenic oocytes of Japanese eel, Anguilla japonica, could be induced in vitro. Co-treatment with very low-density lipoprotein (VLDL) and 11-ketotestosterone (11-KT) resulted in significant oil droplet accumulation. It is therefore suggested that lipids in oil droplets originate, at least in part, from VLDL, and that 11-KT plays an important role in their transfer and/or accumulation into oocytes.

制度:新 ; 文部省報告番号:甲1497号 ; 学位の種類:博士(理学) ; 授与年月日:2001-03-15 ; 早大学位記番号:新3069 ; 理工学図書館請求番号:2531