Nobuo Yaegashi

Tohoku J. Exp. Med., 221: 287-298, 2010. In the version of this article published in the August issue, 2010, the affiliation number of the tenth author (Shigeru Tsuchiya) was mistyped (page 287). The correct affiliation is shown above. In addition, the lettering of ‘ZT’ is a misprint for ‘CT’ in panels A, B and C of Figures 6 and 7 (pages 294 and 295).

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.

The zygote centrosome, consisting of both paternal and maternal centrosomal components, is the microtubule-organizing center necessary for pronuclear migration and positioning in fertilization. Maternal centrosomal function in microtubule organization and pronuclear positioning, however, remains unclear. In the present study, we sought to elucidate the function of maternal centrosomes during bovine parthenotes in the microtubule organizational processes required to move the pronucleus to the cell center without sperm centrosomal components. Microtubule organization, pronuclear position, and distribution of gamma-tubulin, which is thought to be the major component of maternal centrosomal material, were imaged by immunocytochemistry and conventional epifluorescence microscopy. In bovine parthenotes treated with paclitaxel, a microtubule-stabilizing drug, the cytoplasmic microtubule asters became organized after chemical activation, and the microtubules radiated dynamically toward the female pronucleus. The microtubule patterns correlated well with pronuclear movement to the cell center. Microtubules aggregated at regions of gamma-tubulin concentration, but gamma-tubulin did not localize to a spot until the first interphase of bovine parthenogenesis. These findings indicate that gamma-tubulin is responsible for microtubule organization as the maternal centrosome. In bovine parthenogenesis, the maternal centrosome then organizes cytoplasmic microtubules to move the female pronucleus into the cell center. We propose that the maternal centrosome plays a role as a functional centrosome despite the lack of a sperm contribution, making this structure less competent for microtubule organization in comparison with centrosomes containing sperm centrosomal components.

Laparoscopic surgery has inherent restrictions with respect to the operative field of view and the range of surgical manipulation. Of the two procedures which secure sufficient operative space, the operative view of the gasless method is inferior to that of a pneumoperitoneum. In order to gain greater surgical visualization in gynecological gasless laparoscopy, the authors devised the cul-de-sac packing method employing a metreurynter, an instrument familiar to obstetricians in Japan. A metreurynter was lead into the cul-de-sac, and was inflated with saline, which resulted in the adnexae being raised up. This method was performed in three patients whose preoperative diagnoses were unknown infertility, ovarian cyst, and ectopic pregnancy, respectively. In all cases this method was able to keep the bowels out of the cul-de-sac space. In the first case, we were able to perform a tubal patency test under tension-free conditions, while at the same time bilateral tubal information could be obtained in a single view. In the latter two cases the adnexal lesions were maintained at an inspectional position throughout the operation without the necessity of being held by forceps to prevent them from falling down into the cul-de-sac space. No complications occurred in our three cases. This method will not be useful for patients whose cul-de-sac space is closed due to adhesions. However, except in such cases, this technique supplies a good operative view while being simple, safe, and inexpensive. Furthermore, this method supports gentler and less traumatic manipulation throughout the operation.

To summarize the current management of infertility in Japan, a questionnaire survey was administered. A mail-survey method was used, and surveys were sent to 126 obstetrical and/or gynecological medical facilities in Miyagi Prefecture. The respondents included 86 facilities (68.3%). The majority of participants employed routine assessments, and their records included basal body temperature (98.8%), semen analysis (88.8%), and tubal patency tests (78.8%). Laparoscopic diagnosis, however, was uncommon (15.8%). With respect to treatment, surgical procedures, especially endoscopic procedures, were not generally carried out in addition to medicinal treatment. Sixty-one percent of the respondents performed intrauterine insemination, however assisted reproductive technology (ART) was provided by a few participants, for example, in vitro fertilization-embryo transfer was available at 11.3% of facilities. In self-assessment, the median pregnancy rates for the group undergoing laparoscopy and that not were significant different (30% and 20%, respectively), and those of the group undergoing ART provided and that not were significant different (35% and 20%, respectively). In conclusion, there are various differentials in the methods of diagnosis and treatment of infertility in the medical facilities today, and the outcomes are not always satisfactory. For appropriate management of infertile couples, it will be necessary to more closely manage cooperation between primary care doctors and reproductive specialists.