Prevalence and risk factors of zygotic splitting after 937 848 single embryo transfer cycles.

STUDY QUESTION: What is the prevalence of multiple pregnancy with zygotic splitting after single embryo transfer (SET)? SUMMARY ANSWER: The prevalence of multiple pregnancy with zygotic splitting after SET was 1.36%. WHAT IS KNOWN ALREADY: In 2008, the Japan Society of Obstetrics and Gynaecology (JSOG) recommended the adoption of SET to reduce multiple births. Since then, to improve the clinical pregnancy rate, elective SET using blastocyst transfer and frozen-warmed ET has increased. Blastocyst culture and zona pellucida manipulation, including ICSI and AH, have been widely reported as risk factors for monozygotic twinning. However, all these studies may have included cases with dizygotic pregnancies produced by a transferred embryo and a spontaneous conception. STUDY DESIGN, SIZE, DURATION: A retrospective observational study was performed, based on 937 848 SET cycles in registered ART data from the JSOG between 2007 and 2014. The study was approved by the Registration and Research Subcommittee of the JSOG and Juntendo University Ethics Committee. PARTICIPANTS/MATERIALS, SETTING, METHODS: To identify possible factors affecting the prevalence of zygotic splitting, we identified pregnancies, in which the number of foetuses exceeded the number of gestational sacs (GSs), to restrict our analysis to 'true' zygotic splitting. Multiple logistic regression analysis was performed using singleton pregnancy after SET, as control. P < 0.05 was considered statistically significant. MAIN RESULTS AND THE ROLE OF CHANCE: Fresh and frozen-warmed SET produced 276 934 clinical pregnancies (29.5%/SET), including 4310 twins (1.56% of pregnancies) and 109 triplets (0.04% of pregnancies). Based on sex analysis of dichorionic twins after SET, the prevalence of multiple pregnancy with zygotic splitting was 1.36%. Statistical analysis revealed that compared to singleton pregnancies zygotic splitting pregnancies were associated with frozen-warmed ET cycles (odds ratio [OR] = 1.34; 95% CI: 1.16-1.55), blastocyst culture (OR = 1.79; 95% CI: 1.54-2.09) or AH (OR = 1.21; 95% CI: 1.08-1.35). In fresh ET cycles, the prevalence rate of zygotic splitting pregnancy after single blastocyst transfer was significantly higher than that after SET cycles with cleavage embryos (OR = 2.20; 95% CI: 1.83-2.66). However, no significant difference in ovarian stimulation and fertilization methods was recognized. LIMITATIONS, REASONS FOR CAUTION: In the current Japanese ART registry system, data regarding frozen-warmed ET do not include information about ovarian stimulation and fertilization methods. Registration for AH only began in 2010. There is no way of validating if data submitted by clinics is correct. WIDER IMPLICATIONS OF THE FINDINGS: Clinicians should consider whether to counsel couples about the small increase in the risk of zygotic splitting associated with some embryo manipulations. STUDY FUNDING/COMPETING INTEREST(S): No external funds were used for the study. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: None.

[Changes in the management of urolithiasis: endourologic treatment of calculi in the upper urinary tract].

Three hundred seventy cases with calculi in upper urinary tract were treated by endourology, 210 cases were subjects of percutaneous nephrolithotripsy (PNL) and 160 cases of transurethral ureterolithotripsy (TUL), in Nara Medical University Hospital and 13 affiliated hospitals. Of the PNL cases, PNL was completed in 184 cases (87.6%) and not completed in 16 cases (12.4%). 168 cases (80.0%) had successful results by PNL alone, stone-free or stone fragments less than 5 mm, in spite of the stone location and size. No serious adverse effect was experienced throughout the study. However, changes like a scar formation or fibrosis around the nephrostomy tract were revealed as a late complication by excretory urography, computed tomography and renal scanning. Of the 160 TUL cases, TUL was successful in 132 cases (82.5%) and unsuccessful in 28 cases (17.5%). The results of TUL for the calculi above the upper iliac cresta were not favorable, success rate for stone 6-10 mm in diameter was 70.3% and that for stones larger than 11 mm 37.5%. However, the results of TUL for the calculi below the upper ileac cresta were favorable, the success rate for the 6-10 mm calculi was 91.5% and for the calculi larger than 11 mm 88.4%. Of 28 TUL failures, 7 cases underwent PNL and 21 cases received open surgery. Throughout our endourologic treatments, the most problematic stone was calculi impact in the ureter. The indication of endourology for the calculi in upper urinary tract is discussed with consideration of ESWL which is becoming the main stream of stone treatment.

Decrease in the c-myb gene transcript during differentiation of mouse teratocarcinoma stem cells.

Transcript of the c-myb gene, one of the proto-oncogenes, was clearly detected in undifferentiated mouse F9 teratocarcinoma stem cells, but not in terminally differentiated mouse parietal endoderm PYS-2 cells. As F9 cells can be induced to differentiate into parietal endoderm-like cells by the addition of retinoic acid and dibutyryl cAMP, we examined levels of the c-myb transcript under this experimental condition and found that the c-myb transcript was decreased significantly. Thus, a decrease in the c-myb transcript is probably related to early differentiation of mammalian cells.

[Clinical analysis of primary vesicoureteral reflux in children].

The retrospective analysis of 64 patients between 1 month and 14 years old with 87 primary vesicoureteral units with reflux was reviewed. They were followed-up for a period of 3 to 60 months. Thirty one patients were managed conservatively by chemotherapy (group A) and 28 patients were treated surgically. As the anti-reflux operation the Politano-Leadbetter procedure was used in 27 patients and the modified Politano-Leadbetter procedure in 1 patient (group B). Five patients were not treated (group C). In 13 of the 30 renal units of group A, the vesico-ureteral reflux disappeared spontaneously and in group B the post-operative cystourethrography revealed cure of reflux in all the renal units. In 2 of the 21 renal units of group A excretory urography (IVP) revealed improvement and in 3 deterioration. Post-operative IVP revealed improvement in 13 of 39 renal units of group B and in 2 deterioration. In 3 of the 22 renal units of group A the renogram revealed improvement and in 3 deterioration. The post-operative renogram revealed improvement in 8 of the 28 renal units of group B and deterioration in renal units. Analysis was also made according to the vesicoureteral reflux grade.

Isolation and characterization of the cDNAs corresponding to mRNAs abundant in undifferentiated mouse embryonal teratocarcinoma stem cells, but not in differentiated mouse parietal endoderm cells.

As retinoic acid (RA) and dibutyryl cAMP (cAMP) treatment induces differentiation of mouse teratocarcinoma F9 cells into parietal endoderm cells in vitro, we initiated studies on the molecular mechanisms underlying early mammalian cell differentiation in this system. We constructed cDNA libraries on the poly(A)+RNAs extracted from the undifferentiated F9 cells, and screened for cDNA sequences expressed abundantly in F9 cells, but not in terminally differentiated mouse parietal endoderm PYS-2 cells. Six different cDNA clones were isolated and characterized. The levels of RNAs hybridizable to these clones were at most 5 to 24% in the PYS-2 cells when compared with those in the undifferentiated F9 cells. The six clones were classified into two groups on the basis of their responses to the RA and cAMP treatment. In F9 cells, the levels of RNAs hybridizable to the first group, which contained four clones, were decreased within 72 h after the addition of RA and cAMP, while those of the second group, which contained the remaining two clones, did not decrease significantly. One of the first group clones, named pF9-1, corresponded to the mouse "early transposon-like elements" and another, named pF9-4, hybridized to multi-size RNAs extracted from the undifferentiated F9 cells. The mouse genomic DNA sequences hybridizable to pF9-4 were repeated approximately 5,000 times, and comprise a new gene family, the expression of which is developmentally regulated in mouse F9 cells.

Urinary bladder tumors induced by N-butyl-N-(4-hydroxybutyl)nitrosamine in dogs.

Clinicopathological, radiological, and histological studies were performed on urinary bladder neoplasia induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in five adult beagle dogs and in ten adult mongrel dogs. Tumors of the urinary bladder developed in dogs given various daily doses of BBN p.o. for different periods. The latent period of tumor induction was 4 years in dogs receiving a daily dose of 80 mg of BBN, 2 to 2.5 years in dogs receiving a daily dose of 160 mg of BBN, and 1.5 years in dogs receiving a daily dose of 240 mg of BBN. The total dose of BBN ingested by the dogs until the first tumors were observed by urological examinations was nearly the same in all groups, 100 to 140 g. These results suggest that there is a correlation between dose and induction time, but further dose-response studies are required. Histologically, tumors of the urinary bladder were transitional cell papillomas or transitional cell carcinomas resembling morphologically those found in human cases. It is possible to observe the process of development of urinary bladder tumors from initial lesions to invasive tumors using routine urological examinations. We believe that this experimental model is valuable for clinicopathological studies of urinary bladder tumors.