The Pat1 gene is expressed in the immature oocytes of Xenopus, and is reportedly involved in regulating the translation of maternal mRNAs required for oocyte-maturation. However, it is still unknown when Pat1a first appears in the differentiating ovary of amphibians. To address this issue, we isolated the full-length Pat1a cDNA from the frog Rana rugosa and examined its expression in the differentiating ovary of this frog. Among eight different tissues examined, the Pat1a mRNA was detectable in only the ovary. When frozen sections from the ovaries of tadpoles at various stages of development were immunostained for Vasa-a germ cell-specific protein-and Pat1a, Vasa-immunopositive signals were observed in all of the germ cells, whereas Pat1a signals were confined to the growing oocytes (50-200 μm in diameter), and absent from small germ cells (<50 μm in diameter). Forty days after testosterone injection into tadpoles to induce female-to-male sex-reversal, Pat1a-immunoreactive oocytes had disappeared completely from the sex-reversed gonad, but Vasa-positive small germ cells persisted. Thus, Pat1a would be a good marker for identifying the sexual status of the sex-reversing gonad in amphibians. In addition, fluorescence in situ hybridization analysis showed Pat1a to have an autosomal locus, suggesting that Pat1a transcription is probably regulated by a tissue-specific transcription factor in R. rugosa.
Background and study aimsMagnifying endoscopy with narrow-band imaging (ME-NBI) is more reliable than chromoendoscopy (CE) for delineating the horizontal extent of early gastric cancers prior to endoscopic submucosal dissection (ESD). However, the added benefits of ME-NBI over CE in terms of the difference in magnification level have yet to be elucidated. The aim of this study was to investigate the improvement in diagnostic accuracy for tumor delineation obtained with different magnification levels of ME-NBI following CE.Patients and methodsThis was a retrospective study, performed at a single tertiary referral center. A series of 158 consecutive patients with 161 early gastric cancers resected en bloc using ESD was included in the study. The margins of each lesion were examined in their entirety using CE, followed by low power optical magnifying endoscopy with narrow-band imaging (LM-NBI), and finally the highest power optical magnifying endoscopy with narrow-band imaging (HM-NBI). The primary endpoint was the added benefit, as measured using the successful delineation rate, for the delineation of gastric cancer margins using CE + LM-NBI vs CE, and for CE + LM-NBI + HM-NBI vs CE + LM-NBI.ResultsThe successful delineation rates (95 % CI) using CE, CE + LM-NBI and CE + LM-NBI + HM-NBI were 72.7 % (68.5-79.9 %), 88.9 % (84.2-93.8 %), and 98.1 % (95.8-100 %). The diagnostic accuracy improved significantly for CE + LM-NBI compared with CE (P < 0.001), and for HM-NBI compared with LM-NBI (P < 0.001).ConclusionsHM-NBI is useful for improving diagnostic performance for endoscopic delineation of early gastric cancers, following CE and LM-NBI.
The role of anti-Müllerian hormone (AMH) during gonad development has been studied extensively in many species of mammal, bird, reptile, and fish but remains unresolved in amphibians. In male mammalian embryos, Sox9 activates AMH expression, which initiates regression of the Müllerian ducts. However, Sox9 (Sry-related HMG box 9) is unlikely to initiate AMH in chicken, because AMH precedes Sox9 expression in this species. To clarify whether AMH is involved in testicular differentiation in amphibians, we cloned the full-length AMH cDNA from the Japanese wrinkled frog, Rana rugosa. The AMH gene, which appears to be autosomal, is exclusively expressed in the testis of adult frog among 8 different tissues examined; Sertoli cells are probably responsible for its expression. AMH expression was found in the undifferentiated gonad of both male and female tadpoles, increasing in the differentiating testis. Moreover, we observed consensus binding sites for Sox9 in the 5'-flanking region of the AMH gene. Sox9 stimulated statistically significant AMH expression in luciferase reporter assays when coexpressed in Xenopus kidney-derived A6 cells. However, Sox9 expression showed no sexual dimorphism when AMH expression was up-regulated in the developing testis. These results, taken together, suggest that AMH is probably involved in testicular differentiation in R. rugosa, although an additional, perhaps tissue-specific, transcription factor may be required for the regulation of AMH transcription.
A 74-year-old female, who was diagnosed with superficial esophageal cancer, underwent endoscopic submucosal dissection (ESD) at another hospital, but a perforation occurred during the procedure. The perforation was closed with endoscopic clips, and the ESD was halted. The patient was referred to our hospital, and ESD was retried. There was severe fibrosis around the lesion, and injections into the submucosal layer were difficult. In addition, it was not possible to identify the submucosal layer, and making an oral-side incision caused a large perforation along the incision line. As continuing the submucosal dissection with an endoknife was considered difficult, the lesion was finally resected with hybrid ESD using a snare. The perforation was closed using polyglycolic acid (PGA) sheets and fibrin glue. Endoscopy performed 6 days later showed that the defect had been closed, and no contrast leakage was detected. Follow-up endoscopy conducted 3 months after the ESD showed ulcer healing at the dissection site and scar formation, but no residual tumor or esophageal stricture was noted. Our experience suggests that the use of PGA sheets with fibrin glue is a feasible, safe, and effective way of treating large esophageal perforations during ESD.
The shortage of medical doctors is now a serious social problem in Japan. There are 2.1 physicians per 1000 residents in Japan, fewer than most other OECD countries. Tokushima Prefecture has the second highest population of medical doctors in Japan, but the shortage of medical doctors in rural areas was observed by an uneven distribution. Primary care practice was started in the education of clinical clerkship for 5th grade medical students of our university since July, 2008. They round a variety of hospitals, clinics and facilities for nursing-care during one week in Kaihu county where has a severe problem in the shortage of medical doctors in Tokushima Prefecture. In order to research the efficacy of the primary care practice, we have administered a questionnaire for medical students before and after the lecture and practice, and the intensity was estimated in each student by using visual analogue scale. The results showed that the practice was more meaningful in increasing the intensity for interest and passion for community medicine and medicine in remote area than the lecture. Our data indicate that it is important to prepare more courses to learn primary care and general medicine in our clinical practice system to continue the interest and passion in community medicine.
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