Hyogo Prefectural Institute for Educational Research and In-Service Training

The purpose of this study was to cryopreserve bovine oocytes for subsequent blastocyst production by in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT). A vitrification procedure using gel-loading tips as containers was applied to cryopreserve in vitro-matured and denuded oocytes. In Experiment 1, oocytes were vitrified-warmed in vitrification solution (VS) containing 25, 28, 31, or 40% ethylene glycol (EG) and 1.0 M sucrose. The proportions of survived oocytes that appeared to be morphologically normal after warming, and cleaved oocytes after IVF were lower with 25% EG-based VS when compared with 28–40% EG-based VS. Blastocyst yields 8 days after IVF of oocytes vitrified-warmed in 28 and 31% EG-based VS (12 and 17%, respectively) were not significantly different from those of the fresh control group (32%). Day-7 blastocysts derived from vitrified oocytes were composed of a smaller number of inner cell mass (ICM) and trophectoderm cells than the fresh Day-7 blastocysts. In Experiment 2, oocytes vitrified-warmed in 31% EG-based VS were subjected to enucleation and SCNT. The proportions of oocytes fused and cleaved in the vitrified group were comparable to those in the fresh control group. Blastocyst yields 6 and 7 days after SCNT of vitrified oocytes were lower than those of control oocytes, but 8 days after the SCNT, the difference became statistically comparable (45 versus 58% in control group). ICM and trophectoderm cell numbers in Day-7 blastocysts derived from vitrified oocytes were smaller than those of control blastocysts due to a slower developmental rate. In conclusion, bovine oocytes cryopreserved by vitrification in gel-loading tip were capable of developing into blastocysts after conventional IVF and SCNT, with slightly smaller cell numbers and a slower developmental rate.

高校物理実験の指導上の問題点の一つは，事後指導における実験レポートの指導である。実験レボートのうち．データと計算結果の部分をマイコンに評価させる方法を研究した。評価の観点は，測定回数．測定値の有効数字，計算の検算．計算値の有効数字，実験結果と物理定数表の値との比較，データのばらつき，グラフから求める諸定数などが考えられ，実験題目によって必要な観点をプログラムする。生徒は実験レポートを書いた後，データと計算結果をマイコンに入力して評価を受ける。指導教師はこの部分をチェックして，実験ノートの検討事項などを中心に評価，指導する。具体的な実施例として＂記録タイマーによる重力加速度の測定”を紹介した。愛媛県総合教育センターで実施される小・中・高校教員対象の理科実験講座で試行した結果は満足なものであり，ほとんどマイコンに触れた経験のない教師でも容易に操作することができた。マイコンが小・中・高校の理科実験室へお目見えする日も近いので，一つの効果的な使用法として，この研究を続けていきたい。