Black porgy, Acanthopagrus schlegeli Bleeker, a marine protandrous hermaphrodite, is functional male for the first two years of life but begins to sexually change to female after the third year. Testicular tissue and ovarian tissue was separated by connective tissue in the bisexual gonad. This sex pattern provides a very good model to study the endocrine mechanism of sex change in fish. The annual profiles of plasma estradiol, vitellogenin and 11-ketotestosterone concentrations in males were significantly different from those in the three-year-old females. Significantly high levels of plasma estradiol during the prespawning/spawning season and low levels of plasma 11-ketotestosterone during the spawning season were observed in the inversing females. No difference of plasma testosterone levels was observed in males and females. Oral administration of estradiol stimulated high levels of gonadal aromatase activity, plasma gonadotropin II levels and sex change in the two-year-old fish. Exogenous estradiol administered for 5-6 months induced a reversible sex change in one- and two-year-old fish. The sensitive period for estradiol treatment of sex change is from early prespawning to spawning season. Implantation with testosterone for more than a year could not block the natural sex change in three-year-old fish. Exogenous aromatase inhibitors (1,4,6-androstatriene-3,17-dione or fadrozole) suppressed aromatase activity in the brain. Oral administration with aromatase inhibitors for a year further inhibited the natural sex change in three-year-old black porgy and all fish became functional male with spermiation. Estrogen receptor alpha gene in the ovarian tissue of bisexual gonad is significantly less expressed than that in the vitellogenic ovary of female on the basis of reverse-transcription polymerase-chain reaction. There was no difference in the annual profiles of the plasma gonadotropin II levels in the males and natural inversing females. Plasma gonadotropin II levels were significantly higher in estradiol-treated group than those in the control. It is concluded that estradiol, aromatase activity and estrogen receptor in the ovarian tissue play an important role in the natural and controlled sex change in black porgy. The association of gonadotropin and sex change in black porgy is not clear.

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BackgroundTo retrospectively review the efficacy and organ preservation experience for muscle-invasive bladder cancer by trimodality therapy at our institution.MethodsBetween July 2004 and February 2012, seventy patients (M/F = 55/15; median age = 69 years) of lymph node negative localized muscle-invasive bladder cancer were treated primarily with trimodality approach including transurethral resection of bladder tumor (TURBT) prior to combined chemotherapy and radiotherapy (CCRT). Radiotherapy consisted of initial large field size irradiation with 3D conformal technique (3D-CRT), followed by cone-down tumor bed boost with intensity modulated radiotherapy (IMRT) technique. The median total doses delivered to bladder tumor bed and whole bladder were 59.4Gy and 40.0Gy, respectively. No patient received neoadjuvant chemotherapy (NAC). Weekly cisplatin was administered during radiotherapy. Toxicity was scored according to the RTOG criteria. Tumor response was evaluated both cystoscopically and radiographically 3 months after treatment.ResultsThe numbers of patients with T2, T3 and T4 lesions were 41, 16 and 13, respectively. Overall survival (OS) and progression-free survival (PFS) at 2 and 5 year were 65.7%, 51.9% and 50.8%, 39.9%, respectively, after a median follow-up time of 24 months. Local-regional control and distant metastasis free survival at 2 year were 69.8% and 73.5%, respectively. Complete response (CR) rate assessed three month after CCRT was 78.1%. Ten patients (20%) had local recurrence after initial CR (n = 50), 3 of them were superficial recurrence. One patient underwent radical cystectomy after recurrence. The overall 5-year bladder intact survival was 49.0% (95% CI, 35.5% to 62.5%). Acute toxicities were limited to grade 1-2. One patient developed late grade 3 GU toxicity.ConclusionsOur result suggested that trimodality bladder-sparing approach without NAC or dose-intensification could be well-tolerated with a high CR rate and bladder preserving rate for muscle-invasive bladder cancer.

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