Possible selection of viable human blastocysts after vitrification by monitoring morphological changes.

PURPOSE: Morphological assessment of human blastocysts has been effective for selecting embryos with high potential. However, they often show repeated shrinkage and expansion toward their hatching. Here we assessed whether capturing morphological changes over time of vitrified-warmed blastocysts could lead to a better selection of viable embryos from shrunken blastocysts. METHODS: The implantation rates of vitrified-warmed blastocysts that were shrunken or expanded (developing) at the time of loading for transfer were compared among 2,729 cycles that were subjected to single blastocyst transfer. Vitrified (107) and fresh blastocysts (17) were donated for the experimental study. To assess the relationship between morphology (expanded vs. shrunken) and the mitochondrial respiration of blastocysts, the oxygen consumption rate (OCR) was analyzed for 55 specimens using an uncoupler of oxidative phosphorylation. The remaining 69 blastocysts were used for recording morphological changes every 15 min for 48 h after warming. RESULTS: Because there were no surplus embryos, 7 % of the vitrified-warmed blastocysts were shrunken and transferred. The shrunken embryos had sufficient implantation ability (40 %). The OCR of the shrunken embryos was significantly lower than that of their expanded counterparts. Upon exposure to the uncoupler, the OCR of some shrunken embryos increased to levels similar to the expanded specimens. Time-lapse images revealed some shrunken embryos which formed blastocoel by 5 h following warming exhibited developmental competence to the hatched stage. CONCLUSIONS: Data of the present study suggest a group of shrunken blastocysts contains many viable and clinically available embryos and time-lapse observation of vitrified-warmed blastocysts is a potential method to distinguish viable embryos from shrunken blastocysts.

[Anatomical study of the human lingual muscle. Myofibrous organization of the extrinsic muscles].

The organization and distribution of fibre types in the extrinsic human muscles of 34 males and 19 females were determined by Sudan black B staining. 1) According to our observation, the Genio-hyo-glossus consists of two large bundles; and upper bundle and a lower bundle. The Hyo-glossus is thin, flat and the Stlo-glossus is shorter and smaller. 2) These muscles are composed of small bundles of the fibre which could be seen under microscopic. These contain many small fatty cells. 3) The cross-sectional area (mm2) and the total number of the muscle fibres is highest in the Genio-hyo-glossus. The number of fibres per mm2 is highest in of the Hyo-glossus. The cross-sectional size of muscle fibre (micron) in the Stlo-glossus is generally larger than others. 4) Comparison with other muscles as in sucking show the muscle fibre size in the laryngeal muscles to be greatest. The Cross-sectional area and the total number of muscle fibre is greatest in the Genio-hyo-glossus. 5) Three fibre types of muscle could be discerned in terms of their reaction to pigments and cellular: red muscle fibre a positive reacted positively; white muscle fibres has a weak reaction; intermediate muscle fibres reacted intermediately. White muscle fibres are localized in the external layer, in contrast to red and intermediate muscle fibres which are localized in the inner layer of the extrinsic muscles. The percentage distribution of red muscle fibres in the Hyo-glossus and Stlo-glossus is more than Genio-hyo-glossus. These results suggest that Genio-hyo-glossus acts as a power generating force in contrast to the Hyo-glossus and Stlo-glossus which are fatigue-resisting.