Expression and localization of aquaporin 1b during oocyte development in the Japanese eel (Anguilla japonica)

To elucidate the molecular mechanisms underling hydration during oocyte maturation, we characterized the structure of Japanese eel (Anguilla japonica) novel-water selective aquaporin 1 (AQP1b) that thought to be involved in oocyte hydration. The aqp1b cDNA encodes a 263 amino acid protein that includes the six potential transmembrane domains and two Asn-Pro-Ala motifs. Reverse transcription-polymerase chain reaction showed transcription of Japanese eel aqp1b in ovary and testis but not in the other tissues. In situ hybridization studies with the eel aqp1b cRNA probe revealed intense eel aqp1b signal in the oocytes at the perinucleolus stage and the signals became faint during the process of oocyte development. Light microscopic immunocytochemical analysis of ovary revealed that the Japanese eel AQP1b was expressed in the cytoplasm around the yolk globules which were located in the peripheral region of oocytes during the primary yolk globule stage; thereafter, the immunoreactivity was observed throughout the cytoplasm of oocyte as vitellogenesis progressed. The immunoreactivity became localized around the large membrane-limited yolk masses which were formed by the fusion of yolk globules during the oocyte maturation phase. These results together indicate that AQP1b, which is synthesized in the oocyte during the process of oocyte growth, is essential for mediating water uptake into eel oocytes

Effect of tank shape on survival and growth of Pacific bluefin tuna Thunnus orientalis larvae

We examined the effect of rearing tank shape on survival and growth of Pacific bluefin tuna Thunnus orientalis larvae. Cylindrical (1.7 × 103 cm2 water surface area; 30 cm deep) and rectangular (1.8 × 103 cm2 water surface area; 28 cm deep) tanks (n = 3 each) were filled with 50 l of seawater. One air stone with a 100 ml/min aeration rate was set at the bottom center of each tank. Light intensity at the water surface was 2000 lx with a photoperiod of 24 L:0D. Larvae were introduced into each tank at a rate of 10 individuals/l at 2 days post-hatching (dph). Rotifers were fed at 10 individuals/ml and their distribution in tanks was measured. Survival of larvae in cylindrical tanks (CT; 52.7 ± 5.1%) at 8 dph was higher than that in rectangular tanks (RT; 0.8 ± 0.7%, p < .01). Meanwhile, larvae growth was not significantly different between tank shapes either in body length (CT: 4.23?±?0.26?mm; RT: 4.09 ± 0.20 mm) or dry weights (CT: 95.1 ± 17.6 μg; RT: 67.7 ± 10.9 μg). The swimbladder inflation rate of larvae also did not differ significantly between tank shapes (CT: 16.5 ± 14.5%; RT: 56.9 ± 3.47%). Rotifer distribution was higher at tank bottom in both shapes (p < .05). Two-phase bubbly flow simulations in the tanks revealed that the low-flow area was larger in the RT. The low-flow area at tank bottom varied by tank shape, occurring at the edge of the tank wall on the bottom in the CT, and from the center of the tank (air stone) to the tank wall in the RT. These low-flow areas at tank bottom coincided with areas of higher rotifer distribution, which may be a cause of sinking syndrome in fish larvae. Our results indicate that small-scale (50-l) PBT larviculture experiments can be conducted using a CT with the present aeration system, and that an RT requires an improved aerator in place of the single air stone

Significant impact of biochemical recurrence on overall mortality in patients with high-risk prostate cancer after carbon-ion radiotherapy combined with androgen deprivation therapy

BACKGROUNDWhether biochemical recurrence (BR) is a significant predictive factor of mortality after definitive radiation therapy for prostate cancer remains unknown. The aim of the current study was to investigate the relation between BR and overall mortality (OAM) in high-risk prostate cancer patients who were treated with carbon-ion radiotherapy (CIRT) and had long-term follow-up in 2 prospective trials.METHODSIn the 2 phase 2 clinical trials, which involved 466 prostate cancer patients who received 63.0 to 66.0 Gy of CIRT (relative biological effect) in 20 fractions between 2000 and 2007, 324 patients who were deemed to be at high risk on the basis of the modified D\u27Amico classification criteria and received CIRT along with androgen-deprivation therapy (ADT) were examined. The OAM rate was adjusted for the ADT duration, and multivariate analyses using a Cox proportional hazards model were performed for OAM with BR as a time-dependent covariate.RESULTSThe median follow-up period was 107.4 months, and the 5- and 10-year OAM rates after adjustments for the ADT duration were 7.0% (95% confidence interval [CI], 4.0%-9.4%) and 23.9% (95% CI, 16.4%-26.2%), respectively. A multivariate analysis revealed that the presence of BR (hazard ratio, 2.82; 95% Cl, 1.57-5.08; P = .001) was one of the predictive factors for OAM. On the other hand, the duration of ADT had no impact on OAM.CONCLUSIONSBR after CIRT combined with ADT is an independent predictive factor for OAM in high-risk prostate cancer patients. The results of this study could be applied to other high-dose radiation therapies

Quantitative comparisons of maternal transcripts related to cell division between good and poor quality eggs from artificially matured Japanese eel Anguilla japonica

The current method of artificial egg production in Japanese eel does not always yield good quality eggs, but the molecular basis for the decrease in egg quality remains unclear. In this study, we compared the levels of 74 maternal transcripts related to cell division among good quality eggs, developing poor quality eggs (i.e., those producing a viable morula embryo without hatching), and non-developing poor quality eggs (i.e., developmentally incompetent eggs) to determine the molecular characteristics of poor quality eggs produced by artificially matured Japanese eel. Only one transcript (lsm7) had a lower level in developing poor quality than in good quality eggs, with the others being present at similar levels between the two types of egg. The levels of 11 transcripts (e.g., cdc26, psma7) were lower in non-developing poor quality than in good quality eggs. These results suggest that insufficient or reduced levels of maternal mRNA related to cell division are associated with the loss of egg quality in artificially matured Japanese eel, and that maternal characteristics other than quantity may affect the developmental competence of poor quality eggs

Real‐world risk of lower‐limb amputation associated with sodium–glucose cotransporter 2 inhibitors versus metformin: A propensity score‐matched model analysis in Japan

ABSTRACT Aims/Introduction We aimed to clarify the real‐world risk of lower‐limb amputation and identify factors related to increased risk in Japanese patients with type 2 diabetes using sodium–glucose cotransporter 2 inhibitors (SGLT2is). Materials and Methods We carried out a retrospective observational cohort study utilizing the Japanese Medical Data Vision, a diagnosis procedure combination database. We identified 107,296 patients with type 2 diabetes who were initiated on SGLT2is or metformin (control; n = 53,648 per group) using 1:1 propensity score matching from April 2014 to October 2019. The hazard ratio (HR) for the risk of lower‐limb amputation was analyzed using a Cox proportional hazards model adjusted for patients' baseline characteristics and use of concomitant medical agents. Results Of the 107,296 patients, 66 (0.06%); that is, 41 (0.08%) in the SGLT2is group and 25 (0.05%) in the metformin group, underwent amputation, with no significant difference in the proportions between the groups. There was no significant difference in the risk of amputation between the SGLT2is and metformin groups (HR 1.34, 95% confidence interval [CI] 0.80–2.24). However, female sex (HR 2.78, 95% CI 1.12–6.94) and use of strong statins (HR 2.68; 95% CI 1.18–8.20) were significantly associated with a higher risk of amputation in the SGLT2is group than in the metformin group. Conclusions SGLT2is might not be related to an increased risk of lower‐limb amputation in patients with type 2 diabetes in real‐world clinical practice. The possible increased risk of SGLT2is‐associated amputation in female patients with type 2 diabetes and patients with type 2 diabetes requiring strong statins is notable

Maternal transcripts in good and poor quality eggs from Japanese eel, Anguilla japonica—their identification by large‐scale quantitative analysis

Our understanding of maternal control of development in vertebrates remains incomplete. In this study, we investigated levels of maternal transcripts in good and poor quality eggs from artificially matured Japanese eel, using RNA-Seq and quantitative polymerase chain reaction (qPCR), to identify candidate maternal transcripts related to development. De novo assembly or mapping of reads to the eel draft genome yielded 619,029 contigs and 85,906 transcripts, respectively; normalized read counts to these assemblies were calculated using reads (RPKM) or fragments (FPKM) per kilobase of transcript per million mapped reads. In silico screening identified 1,594 contigs and 150 transcripts with lower RPKM or FPKM in poor than in good quality eggs, 245 contigs, and 85 transcripts of which could be annotated by BLASTx, respectively. From selected contigs or transcripts, six genes (dnajb4, gnpat, card14, pdp1, fcgbp, ttn) had significantly lower messenger RNA levels in poor than in good quality eggs by qPCR. Multiple regression analysis showed that five genes (gnpat, b4galnt1, acsl6, rtkn, trim24) significantly correlated with hatchability. Taken together, 10 genes were identified as candidate maternal transcripts, regulating development in Japanese eel. Our results contribute to understanding the molecular basis for maternal control of development in vertebrates

Transcriptome characterization of gonadal sex differentiation in Pacific bluefin tuna, Thunnus orientalis (Temminck et Schlegel)

Abstract Tunas (genus Thunnus) are one of the most ecologically and commercially important fish worldwide. To establish a biological basis for reproduction in this globally essential species, we have recently studied crucial reproductive aspects of the Pacific bluefin tuna (T. orientalis; PBT), as a model of tuna species, based on our closed-cycle aquaculture technology. In this study, we clarified the global expression profile of the genes regulating gonadal sex differentiation in PBT, as this developmental process is vital to sexual reproduction. Based on the results of our comparative (RNA-sequencing) and temporal (qRT-PCR) transcriptome analyses using the updated genome dataset, we propose the molecular mechanisms of gonadal sex differentiation in PBT. In female gonads, foxl2 and cyp19a1a (coding aromatase) are expressed at the onset of sex differentiation. Active aromatase-mediated estrogen biosynthesis, which includes positive regulation of cyp19a1a expression by Foxl2, induces ovarian differentiation. By contrast, dmrt1 and gsdf are upregulated in differentiating male gonads lacking active estrogen synthesis. Dmrt1 and Gsdf would mainly promote testicular differentiation. Furthermore, androgen biosynthesis is upregulated in differentiating male gonad. Endogenous androgens may also be vital to testicular differentiation. This study provides the first comprehensive data clarifying the molecular basis for gonadal sex differentiation in tunas