Hyperbranched polymers (HBPs) formed by a self-condensing vinyl polymerization (SCVP) of copolymerization of AB* monomers slowly added into trifunctional C 3* cores under various feed rates were investigated by a kinetic model. The dependences of average molecular weight, polydispersity, degree of branching, and number of structural units of the hyperbranched polymers on the feed rate were calculated by a generating function method. It was found that the final polydispersity index (PDI) can be attained below 1.5 by a slow addition of AB* at a feed rate parameter, φ, less than 2. While the AB* monomers fed quickly, the system with a lower content of the C 3* cores results in a broader molecular weight distribution. A high degree of branching, about 0.66, can be achieved by addition of AB* monomers into a small amount of C 3* cores at φ lower than 10.

STUDY QUESTIONIn PGS, does chromosomal constitution differ among trophectoderm (TE) biopsy sites and between them and the inner cell mass (ICM)?SUMMARY ANSWERThe ploidy concordance between ICM and TE was independent of whether the biopsy site in the TE was near to or far from the ICM.WHAT IS KNOWN ALREADYTE biopsies are considered less harmful to developing embryos than blastomere biopsies. Removal of multi-cellular samples permits high-resolution next-generation sequencing (Veriseq NGS) to detect aneuploidy present in a minority of cells (mosaicism of diploid and aneuploid cells). However, the prevalence of ploidy discrepancies between different TE biopsy sites and the ICM, as well as confined mosaicism (aneuploidy only in a particular area), has not been established.STUDY DESIGN, SIZE, DURATIONBiopsies were taken from a site opposite to the ICM (TE1), near the ICM (TE2) and within the ICM of the same embryo in 33 donated blastocysts obtained from 12 volunteer patients. The samples were analyzed by the Veriseq NGS to assess ploidy concordance.PARTICIPANTS/MATERIALS, SETTING, METHODSThe mean age of the patients was 34.4 years, and samples from all three biopsy sites were achieved in 29 frozen thawed blastocysts. The aneuploid percentage in each sample was interpreted by Veriseq NGS at the finest resolution involving the number of reads after filtering, sample overall noise score, and average quality/alignment scores according to the Veriseq quality control assessment. Ploidy concordance was then assessed between different TE fractions, and between the TE and ICM.MAIN RESULTS AND THE ROLE OF CHANCEThe euploid rates were similar in the TEs and ICM, and no preferential allocation of euploid lineage within a blastocyst was demonstrated. Whether the biopsy site in the TE was near to or far from the ICM, the chromosomal consistency rate was similar [TE1-to-ICM, 86.2% (25/29) versus TE2-to-ICM, 89.7% (26/29); P = 1.0], suggesting that the cells with different chromosomal components may spread randomly throughout the TE. The following two types of inconsistent PGS conclusions between TE and ICM due to confined mosaicism were observed: (i) euploid TE with mosaic ICM (3%) (1/29); and (ii) mosaic TE with euploid ICM (3%) (1/29) or with aneuploid ICM (7%) (2/29). Thus, the overall rate of confined mosaicism was 14% (4/29).LARGE SCALE DATAN/A.LIMITATION, REASONS FOR CAUTIONThe approach used in the present study was affected by biopsy manipulation limitations involving possible cell contamination and the technical challenge of comprehensive chromosomal screening (CCS) procedures.WIDER IMPLICATIONS OF THE FINDINGSThe rate of confined mosaicism in the blastocysts was estimated in this preliminary study, thus, specifying the incidence of biological sampling biases. The results also verified the random distribution of different cell lineages, and the representative value of a single biopsied sample from the TE.STUDY FUNDING AND CONFLICT OF INTEREST(S)No external funding was obtained; all the authors declare no conflicts of...

BackgroundChromosomal mosaicism is observed as the presence of both euploid and aneuploid cells in a particular blastocyst. Recent studies have reported that the implantation rate of mosaic embryo transfer is remarkably lower than the euploid embryos. The superior capability of next-generation sequencing (NGS) to detect chromosomal mosaicism in preimplantation genetic screening (PGS) remains controversial, and several data displayed similar implantation and pregnancy rates using NGS or array comparative genomic hybridization (aCGH).ResultsIn this study, the main inconsistency of aneuploidy detection and clinical performance between the NGS and aCGH were assessed. The phase I consisted of a parallel comparison in 182 blastocysts from 45 selected PGS patients for both the NGS and aCGH platforms. The phase II retrospectively compared the clinical outcomes of 90 patients with NGS-screened euploid embryo transfer to that of 129 patients with aCGH-screened euploid embryo transfer. The parallel comparison showed that the inconsistency of embryo euploidy was 11.8% (p = 0.01). Chromosomal mosaicism (10.7% with NGS vs. 3.9% with aCGH) and segmental aneuploidy (10.7% with NGS vs. 6.7% with aCGH) contributed to the discrepancy mainly. The chromosomally mosaic embryos (20%–50% of aneuploidy) and several embryos with segmental aneuploidy (≥10 Mbp) were hard to distinguish using the aCGH platform, but could be clearly identified using the NGS platform. After the first euploid embryo cryotransfer, the β-HCG(+) rate and implantation rate significantly increased in the PGS/NGS patients (HCG[+] rate: 73.3% in PGS/NGS vs. 60.5% in PGS/aCGH, p = 0.048; implantation rate: 53.2% in PGS/NGS vs. 45.0% in PGS/aCGH, p = 0.043). The clinical and ongoing pregnancy rates appeared higher in the NGS group, but did not reached statistical significance.ConclusionsThe results demonstrated that the NGS platform can identify embryos with chromosomal mosaicism and segmental aneuploidy more precisely than the aCGH platform, and the following clinical performance of NGS was more favorable.

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Hyperbranched polymers (HBPs) formed by the self-condensing vinyl polymerization (SCVP) or self-condensing ring-opening polymerization (SCROP) of monomer AB activated by stimuli with various reactivities were investigated by the generating function method. Two different cases were discussed: in case I, the concentration of the stimulus decayed during the activating reaction, and in case II, the stimulus acted as a catalyst to activate the monomer AB, and the change in stimulus concentration was neglected. The reduced number-and weight-average degree of polymerization (DP n *and DP w *) and degree of branching (DB) of the HBPs were found to depend not only on the mole ratio of stimulus to monomer AB (λ) but also on the reactivity ratio of the stimulus (β). The DP n *, DP w * and polydispersity index of the reduced degree of polymerization increased with decreasing reactivity of the stimulus. In case II, when λβ>1, there were only a few influences on the average degree of polymerization by λβ, and the results were similar to those of case I. However, when λβ<1, the degree of polymerization differed significantly between the two cases. The maximum degree of branching of about 0.5 was obtained with near full conversion of A, and the degree of branching depended on the amount and reactivity ratio of the stimulus.

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