Masahito Tachibana

Microtubules and microfilaments are elements of the cytoskeleton that are involved in cell motility. Dynamic and proper organization of the cytoskeleton is crucial for completion of oocyte maturation and fertilization. When performing mammalian developmental and reproductive techniques, information concerning the dynamism of the cytoskeleton is necessary and indispensable. Although rodents are widely used for developmental and reproductive technology, there are numerous differences between the cytoskeletal organization of rodent gametogenesis/fertilization and that of primates, including humans. Herein, a review of cytoskeletal organization during oocyte maturation and fertilization involving the differences between rodents, primates and other mammalian species is presented. Furthermore, we also review the function of the centrosome as a microtubule organizing center (MTOC). Proper information on the kinetics of the cytoskeleton is crucial for further expansion of developmental biology.

The shortage of obstetricians and gynecologists is becoming serious in the Tohoku region. An important task as a local organizer of medical practitioners is for each medical school to make an effort to help the students with an interest in obstetrics and gynecology. Gynecologic endoscopic procedures have advanced and spread rapidly in recent years. The introduction of the endoscope makes the field of obstetrics and gynecology more attractive. We introduced a program of endoscopic surgery using a training box to medical education. The training box was set up in the Department of Medicine Skills lab of Tohoku University Hospital for use by 5^th year medical students. After an introductory video display, the students attempted to operate with devices in the training box. Practice was done based on the syllabus in four stages, culminating in suturing in the box. After practicing for 1 hour, the practice symposium was limited limit to 5 minutes. Every student worked with seriousness which had not been previously demonstrated. Further, practice guidance by the tutor, who was certified as a recognition medicine by this society, was extremely popular with the student. We conclude that introduction of practicing endoscopic surgery using a training box to the medical education deepens the students' interest in obstetrics and gynecology. Such a training device might be useful also for student recruitment to obstetrics and gynecology in the future.

Although intracytoplasmic sperm injection (ICSI) is an innovative treatment for male infertility, a significant number of clinical cases of fertilization failure remain. ICSI overcomes the difficulty in fertilization of sperm entry into the egg cytoplasm. The goal of fertilization, however, is the union of the male and female genomes; sperm incorporation into the oocyte is only the start of fertilization. Human sperm must perform three vital functions after entering the egg: it contributes to the male genome, awakens the quiescent egg, and crystallizes the motility apparatus that unites the sperm and egg nuclei, consummating the fertilization process. During fertilization in most mammalian species, including humans, the sperm introduces the centrosome, which acts as a microtubule organizing center (MTOC). By promoting pronuclear apposition and mitotic spindle formation, the sperm plays the leading part in the induction of “motility”, post-ICSI, in fertilization. The present review introduces the challenges remaining in functional assessment of the human sperm centrosome and discusses the biparental (e.g. rabbit) and maternal (e.g. parthenogenesis) centrosomal contributions to microtubule organization during development.