•  本研究評估了低嵌合體水平（< 50%）胚胎的潛在活力。
• 研究表明嵌合胚胎可以發育成具有不同水平或類型嵌合體的整倍體健康嬰兒。
• 整倍體和嵌合囊胚移植的嬰兒之間沒有觀察到顯著差異。
• 如果患者沒有整倍體胚胎，則可以移植嵌合胚胎，它們有可能植入並發育成整倍體健康嬰兒。
• 這項研究對於諮詢單一嵌合胚胎移植後的臨床結果非常有價值。

. 2020 Sep;37(9):2305-2313.

 doi: 10.1007/s10815-020-01876-6. Epub 2020 Jul 4.Healthy live births from transfer of low-mosaicism embryos after preimplantation genetic testing for aneuploidy

• This study evaluated the potential viability of embryos with low mosaicism level (< 50%) by comparing the clinical outcomes of single mosaic versus euploid blastocyst transfer.  
• Our study indicated that mosaic embryos can develop into euploid healthy infants with various levels or types of mosaicism. 
• No significant difference was observed between infants from euploid and mosaic blastocyst transfers.
• If patients have no euploid embryos, mosaic embryos can be transferred as they have potential for implantation and development into euploid healthy infants. 
• This study is invaluable for counseling clinical results after single mosaic embryo transfers.

 對於 42 歲以上且僅存非整倍體胚胎的患者，鑲嵌染色體胚胎移植是比另外再施行IVF- PGT-A 週期更好的替代方案。

對於年齡小於 42 歲、無法進行額外施行IVF的患者，也應考慮鑲嵌染色體胚胎移植。 

. 2024 Mar;41(3):635-641.

 doi: 10.1007/s10815-024-03027-7. Epub 2024 Jan 17. Mosaic embryo transfer versus additional IVF with PGT-A Cycle: a decision model comparing live birth rate and cost

Mosaic embryo transfers are a superior alternative to an additional cycle of IVF with PGT-A for patients older than 42 whose only remaining embryos are non-euploid. Mosaic embryo transfers also should be considered for patients younger than 42 who are unable to pursue additional autologous IVF cycles

Ficoll-400 密度梯度可用於精蟲分離&產生了更高百分比的活的、成熟的、形態正常的精子。

分層方式: 5% (v/v) density top layer and 90% (v/v) Ficoll-400 density lower layer. 

密度比較: Ficoll density 1.2 g/ml

-----normal spermatozoa (1.17 g/ml)

-----immotile immature sperm cells having lower density of 1.02 g/ml,

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Ficoll-400 density gradient method as an effective sperm preparation technique for assisted reproductive techniques J Hum Reprod Sci. 2016 Jul-Sep; 9(3): 194–199.

Ficoll-400 density gradient yielded higher percentage of live, mature, morphologically normal spermatozoa in an isolated fraction as compared to other three techniques.

 使用密度梯度 density gradient centrifugation來分離狗精子性別的技術並不有效。

. 2018 Dec:199:84-92.  

Sperm sexing with density gradient centrifugation in dogs

•  Sperms were separated using gradients of Percoll® or Ficoll. 
• The percentage of sperm containing X and Y chromosomes was evaluated by qPCR. 
• The use of the Ficoll gradient resulted in the greatest sperm quality after centrifugation. 
• No sperm enhancement containing X or Y chromosome occurred with use of any of the methods 

1. Percoll® 54.8 ± 1.9 compared with 45.2 ± 1.9; 
2. Percoll® associated with Nycodenz® 53.2 ± 2.0 compared with 46.8 ± 2.0; 
3. Ficoll 55.0 ± 1.5 compared with 45.0 ± 1.5 
4. for the percentages of cells containing the X and Y chromosomes, respectively

• The technique of sexing dog sperm using density gradients was not effective for commercial application.

 嵌合胚胎mosaic中可能存在自我矯正機制，嵌合胚胎有可能發育成正常胚胎。

 大多數減數分裂衍生的非整倍體出現在卵子發生過程中。

40歲以上女性產生的卵母細胞中超過50%被證明是染色體異常。

有生育能力的男性精子中染色體異常的發生率在 3% 到 5% 之間。

準確診斷胚胎異常的機率為100%，而整倍體胚胎被分類為臨床適當的比例為61.9%。

J Assist Reprod Genet 2024 May;41(5):1127-1141.   

Hum Reprod. 2019 Apr 1;34(4):758-769.

• There may be a self-correcting mechanism in mosaic embryos, which allows some mosaicisms to potentially develop into normal embryos. 
•  Majority of meiotically derived aneuploidies arise during oogenesis. 
• more than 50 % of oocytes generated by women over the age of 40 years were demonstrated to be chromosomally abnormal. 
• The incidence of chromosome anomalies ranged between 3 and 5 % in the sperm of fertile men. 
• The probability of accurately diagnosing an embryo as abnormal was 100%, while the proportion of euploid embryos classified as clinically suitable was 61.9%. 

Figure 2

Blastocyst chromosomal profiles related to culture outcomes. Euploid blastocysts and those presenting with chromosomal gains and mosaicism were significantly more likely to remain viable 12 days post-fertilisation (dpf), compared to blastocysts with chromosomal losses or multiple aberrations.