95 IN VITRO MATURATION AND FERTILIZATION OF OOCYTES FROM OVARIAN TISSUES CRYOPRESERVED AND XENOGRAFTED INTO NUDE MICE

Primordial follicles act as stores of ovarian follicles and are potential sources of oocytes for medical, agricultural, and zoological purposes. Ovarian xenografting seems to be advantageous for maturing the oocytes in primordial follicles (primordial oocytes) and useful for the conservation and reproduction of domestic or endangered animals. We have generated viable embryos from porcine primordial oocytes xenografted into nude mice (Kaneko et al. 2006 Reproduction). Xenografting of ovarian tissues after cryopreservation would be a very powerful tool for this purpose. Recently, Moniruzzaman et al. 2009 Theriogenology) reported that follicles were able to develop to the pre-antral stage in ovarian tissues after cryopreservation and xenografting, but that oocytes were not obtainable from them. In the present study, we vitrified the tissue after different immersion periods in a cryoprotectant, ethylene glycol (EG), and evaluated the possibility of oocyte collection, and also their maturation and fertilization abilities. Ovarian tissue from piglets approximately 20 days old was minced into cubes of about 1.0 to 2.0 mm. After equilibration in 4% EG in IVC-PyrLac (Kikuchi et al. 2002 Biol. Reprod.) as a base solution (BS) for 15 min, they were immersed in vitrification solution (35% EG, 5% polyvinyl pyrrolidone, and 0.3 M trehalose in BS) for 45 s or 7 min (45-s and 7-min immersion groups, respectively), then dropped with about 4 μL of vitrification solution into liquid nitrogen (LN2). After storage in LN2, microdroplets were transferred in warming solution (0.4 M trehalose in BS) at 37°C for 2 min, then consecutively transferred for 2-min periods into 0.2 M, 0.1 M, or 0.05 M trehalose in BS.As described previously (Kaneko et al. 2006 Reproduction), 20 to 30 pieces of tissue were grafted into kidney capsules of ovariectomized nude mice. The host mice were treated with porcine FSH (62.5 U mL-1 in osmotic pomp) for 12 days before assessment of the survival of the ovarian grafts. When antral follicles were evident in the grafts, oocytes were collected using a surgical blade. They were then matured and fertilized in vitro (Kikuchi et al. 2002 Biol. Reprod.). Ovaries containing antral follicles were obtained between 62 and 125 days after grafting from 6 out of 12 mice in the both 45-s and 7-min groups. When a total of 39 and 49 fully grown oocytes, respectively, had been collected from these groups and cultured, the maturation rates calculated on the basis of 1st polar body extrusion were 18% (7/39) and 33% (16/49), respectively. The corresponding rates for sperm-penetrated oocytes were 83% (5/6) and 88% (14/16), respectively. All the oocytes formed male and female pronuclei at 10 h after insemination. The rates in the 2 immersion groups did not differ significantly by chi-square test, with or without Yates’ correction. In conclusion, fully grown porcine oocytes can be collected from primordial follicles that have been cryopreserved and xenografted into nude mice. The period of immersion before vitrification may not affect oocyte maturation or fertilization ability.

130 EXPRESSION AND LOCALIZATION OF µ OPIOID RECEPTOR IN PORCINE PRE-IMPLANTATION EMBRYOS

Embryonic stem cells can become any tissue in the body, excluding a placenta. Growth factors, hormones, and neurotransmitters have been implicated in the regulation of their fate. Because various neural precursors express functional neurotransmitter receptors, as G-protein-coupled receptors, it is anticipated that they are involved in cell fate decisions. Moreover, a high level of endogenous opioids linked to G-protein-coupled receptor above all μ opioid receptors (MOR) has been shown to interfere with normal calcium metabolism and with the activity of the mitogen-activated protein kinase (MAPK). Thus it is very important to understand the possible influence of opioid activities in the regulation of stem cell fate. In this study we investigated the presence of MOR on porcine in vitro-produced embryos at one-cell, 4-cell, morula, and blastocyst stages by immunostaining. The COC were collected by aspiration, cultured in NCSU-37 medium supplemented with hormones for 20 to 22 h, and then in maturation medium without hormones for 24 h. After this time, COC were inseminated with frozen-thawed epididymal spermatozoa at the concentration of 10 × 5 sperm cells mL-1 for 3 h. After removal of cumulus cells, putative zygotes were cultured in IVC Pyr-Lac medium for the first 2 days and in IVC Glu medium until Day 6 (the day of IVF was defined as Day 0). Embryos at different stages were collected at 12, 36, 120, and 144 h post fertilization, and kept in 4% (v/v) paraformaldehyde until examination. All samples were washed and incubated for 30 min in PBS-1%BSA. Controls were incubated in PBS-1% BSA for 90 min, whereas embryos were incubated with a 1 : 2500 dilution of the primary rabbit antibody against the third extracellular loop of MOR. Prior to examination, all samples were washed in PBS and incubated with a FITC-conjugated anti rabbit IgG-secondary antibody diluted 1:200 in Evans Blue/PBS1x. Samples were visualized by laser scanning confocal microscope (Nikon). The immunofluorescence localize, by intense brilliant green, the presence of MOR on blastomers of all stage embryos examined, whereas the embryos of negative control did not show any fluorescent region or spotted coloring. Our results support specific implication of the opioid receptors in developmental process of porcine embryos. Their presence suggests a possible role of MOR in embryonic development. Thus it can be speculated that there is a role for MOR in controlling key events of the stem cell life. However, these primary results must be confirmed by the demonstration of protein expression (by Western blot) of MOR in the embryos and deeply studied to understand the exact functional role of MOR in them at this level. JSPS short-term scholarship.

126 DEVELOPMENT OF SINGLE BLASTOMERES DERIVED FROM PORCINE TWO-CELL EMBRYOS

Monozygotic mice and calves have been produced from demi-2-cell embryos (Wang K et al. 1997 J. Reprod. Dev. 43, 91-95; Tagawa M et al. 2008 Theriogenology 69, 574-82). These studies proved that single blastomeres of 2-cell embryos could still develop properly after being separated. However, such studies are very difficult to perform in pigs due to multiple pregnancies and relatively low success of embryo transfer. The production of genetically identical animals is very useful for animal husbandry, particularly to increase the number of progeny derived from genetically valuable parents. In the present study, we compared the developmental ability to the blastocysts and their quality in terms of total cell number and gene expression of blastomere pairs derived from 2-cell embryos (pair of blastomere for short). Evenly cleaved 2-cell embryos were collected during 24 to 30 h after IVF and IVM of follicular oocytes. They were split into pairs of single blastomeres by gentle pipetting after Pronase treatment for removal of zona pellucida. Blastomeres were then cultured separately in polydimethylsiloxane (PDMS) micro-wells. Embryos were cultured in IVC-PyrLac from Days 0 to 2 (Day 0 was defined as the day of IVF) and in IVC-Glu for next 4 days (Kikuchi K et al. 2002 Biol. Reprod. 66, 1033-1041). At Day 6, single blastocysts were collected for total cell number or gene expression analysis. Eight replications were performed for each analysis. Three genes chosen for real-time PCR were high-mobility group box 1 (HMGB1); ATP synthase, H1 transporting, mitochondrial F1 (ATP5A1); and the small nuclear ribonuclear proteins (LSM2). These genes are considered as markers to identify embryos with high development competence (Withworth KM et al. 2005 Biol. Reprod. 72, 1437-1451). The expression levels were normalized to the housekeeping gene Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein (YWHAG) using standard curve method. Assessment of 42 blastomere pairs at Day 6 showed that the percentages of the pairs developed to blastocysts (36.6 ± 5.3%) or degenerated (46.3 ± 10.3%) were significantly higher than those of the pairs in which one developed to blastocyst and the other degenerated (17.1 ± 7.8%, P < 0.05, 1-way ANOVA followed by Tukey test). Assessment of two blastocysts derived from one pair of blastomeres showed that one blastocyst (B#1) had better morphology than the other (B#2) in term of expansion and B#1s had significantly higher cell number (31.6 ± 2.9) than that of B#2s (19.1 ± 1.9; P < 0.05; 1-way ANOVA). Although the expression levels of ATP5A1, HMBG1, and LSM2 in B#1s (1.08 ± 0.37, 3.51 ± 1.01, and 2.63 ± 1.17, respectively) did not differ from those in B#2s (0.39 ± 0.13, 1.18 ± 0.38, and 1.68 ± 0.83, respectively), they tended to be higher in B#1s compared to B#2s (P < 0.1). In conclusion, blastomere pairs from the same origin had the same potential to develop to the blastocyst stage. However, the qualities of blastocysts in pairs were different.

378 INVOLVEMENT OF THE SPERM TAIL IN TRIGGERING OOCYTE ACTIVATION IN PIGS

In mammals, repetitive increases of the intracellular Ca2+ level, known as Ca2+ oscillations, are observed in oocytes immediately after sperm-oocyte fusion, which is a prerequisite event for oocyte activation. Previous studies indicate that phospholipase C zeta (PLCζ), a strong candidate sperm factor for triggering Ca2+ oscillations, is localized in the sperm head of several mammalian species. We have reported that the rate of pronucleus formation in oocytes injected with a sperm head is lower than that for oocytes injected with a whole spermatozoon (Nakai et al. 2009 IETS). This has given rise to a hypothesis that not only the sperm head but also the tail play a role in inducing oocyte activation in pigs. In this study, we attempted to detect the localization of PLCζ in the pig sperm tail and also its ability to activate porcine oocytes after injection. To clarify the localization of PLCζ in pig sperm, frozen-thawed ejaculated pig sperm were immunostained using an anti-PLCζ antibody that has been reported previously (Kurokawa et al. 2005). Western blotting was also carried out to examine whether PLCζ (72 kDa) was present in the sperm tail. Sperm tails were detached from the head by sonication and then collected after centrifugation in a Percoll density gradient. We also confirmed whether the sperm tail itself had the ability to trigger oocyte activation using the following 4 injection groups: (1)1 sperm head (Head), (2) 1 sperm tail (Tail), (3) 1 sperm head and 1 tail (Head + Tail), and (4) Sham. The nuclear status of the injected oocyte was evaluated at 10 h after injection. In the present study, we used 3 sperm samples that were prepared from different boars. In pig sperm, the acrosome, tail, and post-acrosomal regions were stained by the PLCζ antibody. The signals in both the post-acrosomal and tail regions disappeared after pretreatment with antigenic peptide, but that in the acrosome region was retained. Furthermore, we confirmed the presence of a band of approximately 72 kDa from the sperm tail and also confirmed its disappearance upon pretreatment with antigenic peptide. The rates of oocytes released from metaphase-II arrest in the Head, Tail, and Head+Tail groups were significantly higher than that in the Sham group (P < 0.05 by ANOVA andTukey test). However, most of the oocytes in the Tail group failed to form pronuclei and showed other meiotic stages (anaphase-II, telophase-II, or metaphase-III). In conclusion, we have shown that PLCζ is expressed in the post-acrosomal and tail region of pig sperm. It is suggested that, in the pig, the sperm tail participates in the triggering of oocyte activation. The authors thankRafaelA. Fissore (Department ofVeterinary and Animal Sciences, University of Massachusetts Amherst) for providing the antigenic peptide for PLCζ. This study was supported in part by JSPS Fellowship (71310042 to M.N.) from the Japanese Society for Promotion of Science (JSPS).

Experimental evidence of impact ignition: 100-fold increase of neutron yield by impactor collision

We performed integrated experiments on impact ignition, in which a portion of a deuterated polystyrene (CD) shell was accelerated to about 600 km/s and was collided with precompressed CD fuel. The kinetic energy of the impactor was efficiently converted into thermal energy generating a temperature of about 1.6 keV. We achieved a two-order-of-magnitude increase in the neutron yield by optimizing the timing of the impact collision, demonstrating the high potential of impact ignition for fusion energy production.

Nuclear replacement of in vitro-matured porcine oocytes by a serial centrifugation and fusion method

The objective of the present study was to establish a method for nuclear replacement in metaphase-II (M-II) stage porcine oocytes. Karyoplasts containing M-II chromosomes (K) and cytoplasts without chromosomes (C) were produced from in vitro-matured oocytes by a serial centrifugation method. The oocytes were then reconstructed by fusion of one karyoplast with 1, 2, 3 or 4 cytoplasts (K + 1C, K + 2C, K + 3C and K + 4C, respectively). Reconstructed oocytes, karyoplasts without fusion of any cytoplast (K) and zona-free M-II oocytes (control) were used for experiments. The rates of female pronucleus formation after parthenogenetic activation in all groups of reconstructed oocytes (58.2-77.4%) were not different from those of the K and control groups (58.2% and 66.0%, respectively). In vitro fertilization was carried out to assay the fertilization ability and subsequent embryonic development of the reconstructed oocytes. The cytoplast : karyoplast ratio did not affect the fertilization status (penetration and male pronuclear formation rates) of the oocytes. A significantly high monospermy rate was found in K oocytes (p < 0.05, 61.6%) compared with the other groups (18.2-32.8%). Blastocyst formation rates increased significantly as the number of the cytoplasts fused with karyoplasts increased (p < 0.05, 0.0-15.3%). The blastocyst rate in the K + 4C group (15.3%) was comparable with that of the control (17.8%). Total cell numbers in both the K + 3C and K + 4C groups (16.0 and 15.3 cells, respectively) were comparable with that of the control (26.2 cells). Our results demonstrate that a serial centrifugation and fusion (Centri-Fusion) is an effective method for producing M-II chromosome transferred oocytes with normal fertilization ability and in vitro development. It is suggested that the number of cytoplasts fused with a karyoplast plays a critical role in embryonic development.

Generation of porcine diploid blastocysts after injection of spermatozoa grown in nude mice

It is anticipated that the utilization of spermatogonia through testicular xenografting will open new avenues for the conservation of male gametes. With the aim of establishing this new technique for genetic preservation of pigs, we used it in combination with intracytoplasmic sperm injection (ICSI). Testicular tissues derived from neonatal piglets, which contained seminiferous cords consisting of only gonocytes/spermatogonia, were transplanted under the back skin of castrated nude mice. Between 125 and 192 d after xenografting, sperm (morphologically similar to epididymal sperm) were recovered from 41 of the 65 host mice (63.1%). Testicular spermatozoa from adult boars were used as a positive control. A single spermatozoon was injected into an in vitro matured porcine oocyte, and the oocytes were electro-stimulated and cultured (graft-ICSI and testis-ICSI, respectively). Blastocyst rates in both ICSI groups (24.9% and 37.4%, respectively) were higher (P<0.05) than those without the injection procedure (parthenogenetic; 12.7%) and after injection of a small amount of injection buffer (sham; 13.0%). Rates of diploid blastocysts in both graft-ICSI and testis-ICSI groups (48.9% and 60.6%) were higher (P<0.05) than those in the parthenogenetic and sham groups (13.5% and 28.0%). Therefore, we demonstrated that porcine oocytes injected with xenogeneic sperm have in vitro developmental ability to the blastocyst stage.

270 PRETREATMENTS OF PORCINE SPERM BEFORE INTRACYTOPLASMIC SPERM INJECTION AFFECT QUANTITY OF PLCZETA;

In pigs, the intracytoplasmic sperm injection (ICSI) procedure alone is insufficient to induce oocyte activation for embryonic development. Artificial activation can be accomplished, such as by electrical pulse-enhanced in vitro development to the blastocyst stage (Nakai et al. 2006). It is well known that the sperm factor (phospholipase Cζ; PLCζ) in spermatozoa, which triggers oocyte activation, is diffused into ooplasm when sperm fuse with oocytes. Our previous study showed that the activation rate of porcine oocytes injected with one sonicated sperm head was significantly lower than that of oocytes injected with a whole spermatozoon or with 3 sonicated sperm heads (Nakai et al. IETS 2007). These results suggest that the sonication treatment per se may affect the quantity of PLCζ in sperm. Furthermore, various pretreatments of sperm besides sonication have been conducted (e.g. removal of the sperm membrane) to increase the efficacy of ICSI. In this study, we investigated the effect of pretreatments (sonication, Triton X-100, and repeated cycles of freezing–thawing without cryoprotectant) on the quantity of PLCζ in porcine sperm. Cryopreserved-thawed boar-ejaculated sperm were used for 3 experimental groups: (1) sperm were sonicated for 10 s in pig-fertilization medium (pig-FM; Suzuki et al. 2002; Soni group), (2) freezing–thawing was repeated 3 times in pig-FM without cryoprotectant (3-F/T group), or (3) sperm were incubated in pig-FM supplemented with 0.1 or 1% Triton X-100 at 37°C for 1 min (0.1 and 1% Triton X-100 groups, respectively). Cryopreserved-thawed whole sperm without any treatment was used as a control. Results from staining with fluorescein diacetate and propidium iodide showed that almost all sperm were propidium iodide positive (dead sperm) immediately after the each treatment. In the control group, approximately 40% of sperm were fluorescein diacetate positive (live sperm) after thawing. The presence of PLCζ (72 kDa) was examined by Western blotting using the antibody against the N-terminal 19-mer sequence of porcine PLCζ (Kurokawa et al. 2005). A band corresponding to porcine PLCζ was not detected in any treatment group in any culture period (from 0 to 135 min). In contrast, PLCζ was detected in the control group and in all culture periods. These results strongly suggest that PLCζ in porcine sperm was lost immediately after the pretreatments, such as by sonication, incubation with 0.1 or 1% Triton X-100, and repeated cycles of freezing–thawing. The decrease in PLCζ protein by pretreatment may be one of the causes of incomplete activation of oocytes in porcine ICSI. This work was supported by a Grant-in-Aid for JSPS Fellows.

Appearance, fate and utilization of abnormal porcine embryos produced by in vitro maturation and fertilization

In vitro production (IVP) including in vitro maturation (IVM) and fertilization (IVF) is now an important technology for obtaining live piglets. However, there are still two significant obstacles to the efficient production of viable porcine embryos: (1) polyspermy and (2) fertilization of oocytes arrested at the immature stage. These phenomena relate to production of embryos with abnormal ploidy (polyploidy). To avoid these problems, careful selection of mature oocytes for IVF, and regular monitoring of normal and abnormal fertilization (polyspermy and/or lack of male pronucleus formation) are very important. In our recent studies, however, we have confirmed that some oocytes with abnormal ploidy after polyspermy can develop into diploid embryos with potentially normal developmental ability. The mechanism by which such fertilized polyploid oocytes develop to a normal state during embryo development is still not well understood. Attempts to clarify this mechanism would hopefully reveal data that are very useful for not only IVP but also other technologies such as the production of transgenic or cloned animals using IVM oocytes, including other species, also for human reproductive manipulation. In this review, we focus on studies of normality of IVM oocytes and ploidy of IVP embryos, and try to suggest practical ways of solving the problems mentioned above in pigs.

Selected aspects of advanced porcine reproductive technology

In vitro fertilization (IVF) of in vitro matured (IVM) oocytes in pigs has become the most popular method of studying gametogenesis and embryogenesis in this species. Furthermore, because of recent advances in in vitro culture (IVC) of IVM-IVF embryos, in vitro production (IVP) of embryos now enables us to generate viable embryos as successfully as for in vivo-derived embryos and with less cost and in less time. These technologies contribute not only to developments in reproductive physiology and agriculture but also to the conservation of porcine genetic resources and the production of cloned or genetically modified pigs. However, in IVP, there still remains the problem of abnormal ploidy, which is caused by performing procedures under non-physiological conditions. In recent years, unique technologies such as intracytoplasmic sperm injection (ICSI) or xenografting of gonadal tissue into immunodeficient experimental animals have been developed to help conserve gamete resources. These technologies combined with IVP are expected to be useful for the conservation of gametes from important genetic resources. Here, we discuss the developmental ability and normality of porcine IVP embryos and also the utilization of ICSI and xenografting in advancing biotechnology in pigs.

Streaked x-ray backlighting with twin-slit imager for study of density profile and trajectory of low-density foam target filled with deuterium liquid

Low-density plastic foam filled with liquid deuterium is one of the candidates for inertial fusion target. Density profile and trajectory of 527 nm laser-irradiated planer foam-deuterium target in the acceleration phase were observed with streaked side-on x-ray backlighting. An x-ray imager employing twin slits coupled to an x-ray streak camera was used to simultaneously observe three images of the target: self-emission from the target, x-ray backlighter profile, and the backlit target. The experimentally obtained density profile and trajectory were in good agreement with predictions by one-dimensional hydrodynamic simulation code ILESTA-1D.

93 PRODUCTION OF LIVE PIGLETS BY CRYOPRESERVATION OF IN VITRO-PRODUCED PORCINE ZYGOTES

Successful cryopreservation of in vitro-produced porcine zygotes is reported in the present study. Follicular oocytes were collected from prepubertal gilts. They were matured (IVM), fertilized (IVF), and cultured (IVC) in vitro (Kikuchi et al. 2002 Biol. Reprod. 66, 1033–1041). Ten or 23 h after IVF, the oocytes were centrifuged at 10 000g at 37�C for 20 min to permit visualization of pronuclei. Zygotes with two or three pronuclei were selected under stereomicroscope and used for solid surface vitrification (SSV). Briefly, after equilibration in 4% ethylene glycol (EG) for 15 min, zygotes were washed in vitrification solution (35% EG, 5% polyvinyl pyrrolidone, and 0.3 m trehalose), and then dropped with about 2 µL vitrification solution onto the dry surface of aluminum foil floating on the surface of liquid nitrogen (LN2). Microdroplets were transferred into cryotubes and stored in LN2. During warming, vitrified droplets were transferred in warming solution (0.4 m trehalose) at 37�C for 1 min, and then consecutively transferred for 1-min periods into 0.2 m, 0.1 m, or 0.05 m trehalose solutions. Survival of vitrified/warmed zygotes was determined by their morphology. To assess their developmental competence, vitrified (SSV), cryoprotectant-treated (CT), and untreated (control) zygotes were cultured in vitro for 6 days. There was no difference in developmental competence between control and CT zygotes in terms of cleavage rates (88.1% and 86.1%, respectively), blastocyst rates (23.2% and 20.8%, respectively), and blastocyst cell numbers (38.0 � 2.0 and 41.2 � 1.7, respectively). The rate of live zygotes after SSV and warming was similar to that of the control (93.4% and 100%, respectively). Cleavage rates (71.7% and 86.3%, respectively) and blastocyst rates (15.8% and 24.5%, respectively) of SSV were significantly reduced after vitrification compared to control (P < 0.05, ANOVA). Blastocyst cell numbers of SSV and control embryos were similar (41.2 � 3.4 and 41.6 � 3.3, respectively). There was no difference in developmental ability between zygotes cryopreserved at an early (10 h after IVF) or late (23 h after IVF) pronuclear stage. When embryo culture medium was supplemented with 1 µm of the antioxidant glutathione, development of cryopreserved zygotes to the blastocyst stage did not differ significantly from that of the control zygotes (18.6% and 22.1%, respectively). To test their ability to develop to term, 150 vitrified zygotes were transferred into a recipient, resulting in pregnancy and the production of five live piglets. These data demonstrate that a high rate of porcine zygotes could be successfully cryopreserved at the pronuclear stage, preserving their full developmental competence.

218 DEVELOPMENT OF EVENLY AND UNEVENLY CLEAVED TWO-CELL PORCINE EMBRYOS

Mammalian eggs are so microlecithal that the embryos would be expected to divide in unison and that each division would lead to 2 equal blastomeres, which are believed to have a greater competence for further development than zygotes with unequal cleavage. However, some studies have shown that uneven blastomere size commonly occurs from the very first division in mammals, and it seems to be concerned with the generation of the first cell lineages of the blastocyst cells: trophectoderm and the inner cell mass (Gueth-Hallonet and Maro 1992 Trends Genet. 8, 274–279). In our study, we produced porcine embryos in vitro (Kikuchi et al. 2002 Biol. Reprod. 66, 1031–1041), and newly formed 2-cell embryos were collected. Based on the timing of the first cleavage (30 or 36 h after insemination), the cleavage pattern (E: equal; U: unequal) and the presence or absence of a second cleavage (+ or –) within the first 2 days of IVC was classified into groups: 30E(–), 30E(+), 30U(–), 30U(+), 36E(–), 36E(+), 36U(–), or 36U(+). There was no difference between the 30E and 30U groups in proportions of the 2-cell stage, which had a nucleus in both blastomeres (99.0 � 0.8% and 91.4 � 3.6%, respectively) or between the 36E and 36U groups (98.2 � 1.1% and 88.0 � 7.2%, respectively). Comparison of further development between the 30E and 30U groups showed that there was no difference in blastocyst rates (70.7 � 5.7% and 61.7 � 7.8%, respectively) and total cell numbers (39.1 � 2.1 and 31.7 � 2.3, respectively). Although the blastocyst rate in the 36E group (37.3 � 6.7%) was significantly higher (P < 0.05) than that of the 36U group (12.0 � 5.1%), the total cell number was not different (26.3 � 5.5 and 25.3 � 5.2, respectively). The timing of the first division, however, had a great influence on further development of the embryos; the 30-h cleaved embryos had a greater rate of blastocyst development (68.2 � 6.3%) than did the 36-h embryos (28.2 � 4.8%, P < 0.01 by ANOVA). The cell numbers of blastocysts derived from 30-h cleaved embryos (37.2 � 2.6) were significantly higher than those of the 36-h embryos (26.2 � 2.3, P < 0.01) as well. Two-cell embryos that were newly formed at 30 h and underwent the next cleavage within the first 2 days of IVC (30 + group) had a higher blastocyst rate (74.8 � 7.0%) and greater cell numbers (40.6 � 2.6) than those not showing a second division during this period (30– group; 46.8 � 5.0% and 19.9 � 2.2, respectively). In contrast, for embryos showing the first cleavage at 36 h of insemination, the presence of the next cleavage within 2 days after the first cleavage did not have any effect on embryonic development. These results suggest that the developmental ability of porcine embryos was influenced by the timing and shape of the first cleavage and by the subsequent occurrence of the second cleavage.

[The third repair for pseudoaneurysm following Bentall procedure: report of a case]

A 77-year-old male, who had undergone the Bentall procedure 27 years ago, was admitted to our hospital for the repair of postoperative pseudoaneurysm. This was the 3rd repair, and the pseudoaneurysm was close to the sternum. Total extracorporeal circulation was established with femorofemoral cannulation and sternotomy was performed under deep hypothermia. During sternotomy, we encountered massive hemorrhage due to injury of the aortic graft. We coped effectively with the situation utilizing temporary circulatory arrest. Aortic graft reimplantation was performed under continuous retrograde cerebral perfusion. Collapse of the suture line of the left coronary orifice was recognized and was reconstructed. The patient was discharged uneventfully on the 26th postoperative day.

QSAR and mechanistic interpretation of estrogen receptor binding

A multi-dimensional formulation of the COmmon REactivity PAttern (COREPA) modeling approach has been used to investigate chemical binding to the human estrogen receptor (hER). A training set of 645 chemicals included 497 steroid and environmental chemicals (database of the Chemical Evaluation and Research Institute, Japan - CERI) and 148 chemicals to further explore hER-structure interactions (selected J. Katzenellenbogen references). Upgrades of modeling approaches were introduced for multivariate COREPA analysis, optimal conformational generation and description of the local hydrophobicity of chemicals. Analysis of reactivity patterns based on the distance between nucleophilic sites resulted in identification of distinct interaction types: a steroid-like A-B type described by frontier orbital energies and distance between nucleophilic sites with specific charge requirements; an A-C type where local hydrophobic effects are combined with electronic interactions to modulate binding; and mixed A-B-C (AD) type. Chemicals were grouped by type, then COREPA models were developed for within specific relative binding affinity ranges of >10%, 10 > RBA > or = 0.1%, and 0.1 > RBA > 0.0%. The derived models for each interaction type and affinity range combined specific prefiltering requirements (interatomic distances) and a COREPA classification node using no more than 2 discriminating parameters. The interaction types are becoming less distinct in the lowest activity range for each chemicals of each type; here, the modeling was performed within chemical classes (phenols, phthalates, etc.). The ultimate model was organized as a battery of local models associated to interaction type and mechanism.

[Treatment strategy for acute type A aortic dissection; how to manage mesenteric ischemia]

Mesenteric ischemia is a dreaded complication of acute type A aortic dissection. From January 1994 to December 2004, 134 patients with acute type A aortic dissection were operated. Eleven patients showed postoperative mesenteric ischemia. Mortality of such patients was much higher than that without mesenteric ischemia (81.8 vs. 10.6% , p < 0.0001). Preoperative mesenteric and/or lower extremity ischemia were revealed to be the risk factors of postoperative mesenteric ischemia. Our strategy to manage these patients is as follows; patients who are suffering mesenteric and/or lower extremity ischemia preoperatively, or those whose computed tomography (CT) shows stenosis, obstruction, or dissection of the superior mesenteric artery, should be recognized as high-risk patients of postoperative mesenteric ischemia. Their mesenteric circulation should be examined directly with laparotomy after the central repair. If the mesenteric circulation seems to be suboptimal, iliac artery-superior mesenteric artery bypass should be performed.

Cytoplasmic glutathione regulated by cumulus cells during porcine oocyte maturation affects fertilization and embryonic development in vitro

It is generally accepted that cumulus cells support the nuclear maturation of mammalian oocytes. In the present study, we examined relationships between the cytoplasmic glutathione (GSH) content of porcine oocytes, and oocyte nuclear maturation, fertilization or subsequent embryonic development. Cumulus-oocyte complexes (COCs; control group) and oocytes denuded of cumulus cells after collection (DO 0h group) were cultured for 24h with dibutyryl cAMP, eCG and hCG (first culture step) and then for a further 20h without supplements (second culture step; 44h total culture). After the first culture step, some of the COCs were denuded, either completely (DO 24h group) or partly (H-DO 24h group), and then matured by the second culture step. Also, in the second culture step, some DOs were co-cultured with cumulus cells that had been pre-cultured for 24h (DO 24h+CC group). The maturation rates of all the cumulus-removed groups (DO 0h, DO 24h, H-DO 24h and DO 24h+CC groups) were lower (34.3-45.0%) than that of the control group (64.5%; P<0.05). The GSH contents of matured oocytes in the completely denuded groups (DO 0h, DO 24h and DO 24h+CC groups) were lower (4.03-5.26pmol/oocyte) than that of the control group (9.60pmol/oocyte; P<0.05); however, the H-DO 24h group had an intermediate value (7.0pmol/oocyte). The male pronuclear formation rates of completely denuded oocytes were lower (41.4-59.3%) than that of the control group (89.4%; P<0.05), whereas the H-DO 24h group had an intermediate rate (80.0%). The blastocyst formation rates of the completely denuded oocytes were lower (3.0-4.5%) than that of the control group (19.9%; P<0.05), and the H-DO 24h group again had an intermediate rate (11.6%). The GSH content was correlated with the rates of male pronuclear formation (P<0.01) and blastocyst formation (P<0.01), and also with the number of cells per blastocyst (P<0.01). In conclusion, we inferred that GSH synthesized by intact cumulus cells during maturation culture improved oocyte maturation and played an important role in fertilization and embryonic development.

Development of noninvasive tonometer using resonance phenomenon

A tonometer is used to measure ocular pressure either by shooting a short blast of compressed air onto the cornea or by applying pressure directly to the cornea. At present, the tonometer is the primary instrument available for measuring ocular pressure. However, measuring ocular pressure by such means can either frighten or injure the patient. We propose an improved method of measuring ocular pressure in which the tonometer is applied over the patient's closed eyelid for several seconds. The sensor part of the newly developed tonometer contains a bimorph type transducer and weighs only 28.7 (g). When the sensor is placed on the eyelid and the transducer is vibrated by altering the applied voltage, the current flowing through the transducer changes in relation to the ocular pressure. Ocular pressure can thus be determined based on the current flowing through the system. During measurement, patients are generally unaware of the vibrations of the sensor and report no pain.