Strain difference in tolerance to low-temperature treatment of fertilized mouse oocytes

Background and Aims:  The aim of this study was to determine which mouse strains exhibit tolerance to cooling when fertilized oocytes have been stored at 4°C.
Methods:  In-vitro -fertilization-derived oocytes of eight mouse strains were incubated at 4°C in 20 mmol/L Hepes-potassium modified simplex optimized medium (KSOM) medium for 0, 24, 48, 60 or 72 h, and then returned to normal culture conditions at 37°C in KSOM medium. The rates of development of cultured oocytes into blastocysts and cell numbers of blastocysts were examined. In some cases, a Comet assay was carried out to evaluate DNA damage. In addition, the effects of β-mercaptoethanol on the development of the 4°C-treated oocytes were assessed.
Results:  Of the eight strains tested, BDF1, B6C3F1 and FVB/N strains exhibited relatively higher degrees of tolerance to 4°C treatment and approximately 90%, 83% and 78% of oocytes treated at 4°C for 48 h developed to morphologically normal blastocysts, respectively. Comet assay revealed no clear DNA damage in oocytes treated at 4°C. Treatment with β-mercaptoethanol failed to improve the in vitro survival rate of low-temperature-treated oocytes.
Conclusion:  Strain differences were observed in tolerance to cooling treatment when fertilized oocytes were temporarily treated with 4°C, although the reasons for this remain unclear. (Reprod Med Biol 2006; 5 : 43–50)     

Effects of specific antibodies on the ultrastructure of mouse oocytes

The effects of antiovarian antiserum and monoclonal antibodies to the oolemma antigens on the ultrastructure of mouse oocytes and their microenvironment are studied. The antioolemma monoclonal antibodies cause more pronounced degenerative changes in the oocyte that in its microenvironment. Antiovarian antiserum induces greater changes in the microenvironment than in the oocyte. Changes induced in the oocyte by the antiserum are secondary relative to changes occurring in the microenvironment, while changes observed in the oocyte treated with monoclonal antibodies are primary. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 123, No. 1, pp. 115–119, January, 1997     

Ontogeny and thymus-dependence of T cell surface antigens in Xenopus : flow cytometric studies on monoclonal antibody-stained thymus and spleen

Recently generated anti-Xenopus T cell monoclonal antibodies (mAbs) to the 120 kDA XTLA-1 determinant and against the putative CD5 and CD8 homologues, together with anti-IgM and anti-MHC class II mAbs, are used in dual colour flow cytometric experiments to characterize cell surface antigenic expression on lymphocytes in thymus and spleen of Xenopus laevis during larval and early adult life and also in metamorphosis-inhibited animals. Histological confirmation of T cell emergence early in larval ontogeny is supplied by cryostat sections stained for CD8. Five-day thymectomy i.e. prior to T-lineage cell differentiation in the thymus, abolishes T cell marker expression in the spleen for up to 1 year. Moreover, late larval (20 days) or early adult (3 months) thymectomy (i.e. removal after peripheralization of T cells has occurred) also leads to severe depletion of mAb-defined T cells in the spleen.     

精氨酸加压素（AVP）的衍生物AVP4—8不能作用于AVPV1a受体而诱发电流反应

在微量注射大量肝脏ｍＲＮＡ之后，通过电压箝方法进行功能鉴定，两栖类卵母细胞成功地表达了ＡＶＰＶ１ａ受体。但在灌流ＡＶ４－８溶液时，却不能诱导卵母细胞产生内向振荡电流反应。提示ＡＶＰ４－８不能通过ＡＶＰＶ１ａ受体而介导生理学效应。     

Retinal specificity in eye fragments: investigations on the retinotectal projections of different quarter-eyes in Xenopus laevis

According to Sperry's chemoaffinity hypothesis, the projection of a small eye fragment with a reduced amount of optic fibres should be restricted to that position in the optic tectum corresponding to its own specificity. However, previous investigations on different types of quarter-eyes in Xenopus laevis have revealed that their retinal projection was always restricted to the rostral part of the tectum, no matter what the origin of the remaining retinal quadrant. To get an indication of the state of specificity in such eye fragments, we investigated by electrophysiological and histological methods several features of the retinal projections of temporoventral (TV), naso-ventral (NV) and ventral (V) quarter-eyes which referred to their positional identity. Irrespective of their different origins, the projections were always located in the rostral part of the tectum, the size of the innervated tectal area depending for all fragment types on the size of the quarter-eyes, i.e. number of optic fibres. However, quantitative analyses revealed that with increasing eye size the various fragments expand their projections preferentially into those tectal areas that match their original specificity: TV projection is more concentrated in the rostral tectum, NV eyes expand their projections mainly to the caudal tectum, and V eyes enlarge their projections equally into the medial and caudal tectum. In addition, fibre-tracing experiments with cobaltic lysine showed that, according to the different origins of the quarter-eyes, retinal fibres follow the appropriate branch of the optic tract selectively: fibres of NV and V eyes pass mainly through the medial tract, and most fibres of TV eyes innervate the rostral tectum directly from a central position between the two side branches. All these findings suggest that the different types of quarter-eyes retain their original positional identity. Thus, their rostrally located retinotectal projections are not in register with their retinal specificity. We conclude that in X. laevis local positional markers in the tectum, if present at all, do not influence the development of the retinotectal projection. Instead we suggest a concept of self-sorting of the optic fibres, which can account for the partial innervation of the rostral tectum in different types of quarter-eyes.     

Expression and kinetic characteristics of muscle type acetylcholine receptors in Xenopus oocytes

ＥｘｐｒｅｓｓｉｏｎａｎｄｋｉｎｅｔｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｍｕｓｃｌｅｔｙｐｅａｃｅｔｙｌｃｈｏｌｉｎｅｒｅｃｅｐｔｏｒｓｉｎＸｅｎｏｐｕｓｏｏｃｙｔｅｓＣｈｅｎＨｏｕｃｈａｎｇ（陈厚昌），ＷｕＳｈｕｇｕａｎｇ（吴曙光）（Ｄｅｐａｒｔ...     

Oocyte donation by gamete intra-Fallopian transfer to amenorrhoeic and cycling patients given replacement steroids

Thirteen procedures of oocyte donation by the gamete intra-Fallopiantransfer (GIFT) technique are described. The patients includedsix women with premature ovarian failure, four normally cyclingwomen with unexplained infertility who responded poorly to super-ovulationinduction in preparation for GIFT, and lastly one woman carrierof a 16/21 balanced translocation. Two patients had oocytesdonated on two occasions. Oocyte donors were recruited eitheramong the patients' relatives (n = 4), or among GIFT or IVFpatients (n = 8), who altruistically donated their extra oocytes.Donors were superovulated and oocytes collected laparoscopicallyor vaginally under ultrasound guidance. Donors did not sufferany complications. Recipients were given exogenous oestrogens,and exogenous progesterone was added from the day of donation.Seven clinical pregnancies were obtained (53.8% per attempt);one set of triplets aborted at 14 weeks. Donation took placeon replacement day 12–18 and pregnancies were obtainedin patients receiving oocytes throughout this temporal window.The increasing availability of embryo-freezing facilities willprobably reduce the number of ova available for donation. Therefore,the patients' families may become a precious source of donatedeggs, especially for those patients having large families, withstrong family ties.     

Granulosa cell metabolism and the assessment of oocyte quality in IVF

The progesterone production of the granulosa cells of the cumulus– oocyte complex correlates very well with the cleavagepotential of embryos in an IVF system. The method is simpleand can be easily performed by any laboratory associated withIVF. Furthermore, high intratubal progesterone levels in theimmediate post-ovulatory period are probably important in prolongingthe intra-ampullary residence of the oocyte or embryo untilthe uterine endometnum is optimal for implantation.     

Perurethral ultrasound-guided ovum pickup

Either a percutaneous-transvesical, a transvaginal, or a perurethral-transvesical approach can be used for oocyte recovery under ultrasound guidance in an in vitro fertilization and embryo transfer program. After having experienced these three different approaches in our program, we preferentially used the perurethral-transvesical approach as our routine technique for oocyte recovery under ultrasound guidance. We feel that this method is easier to perform and also carrier less risk for contamination. From January to December 1986, 186 oocyte retrievals under ultrasound guidance were performed. In 7 cases no oocytes were found despite normal ovarian stimulation. A total of 767 oocytes was collected; the fertilization rate was 71.8%. Forty pregnancies were achieved (21.5% per attempt or 27.7% per embryo replacement). Except for transient hematuria, no complications were observed.