Peripheral avian yolk assemblage and its persistence in the blastoderm, studied by trypan blue-induced fluorescence

Summary Shortly after subcutaneous or intraperitoneal injection of nontoxic quantities of trypan blue into laying Japanese quails, red fluorescent yolk granules appear in the peripheral ooplasm of their oocytes at the end of the lampbrush stage or subsequently. Later a red fluorescence can be observed in the apical cytoplasm of the granulosa cells. The results obtained by this method confirm our previous results (Callebaut 1974) obtained by autoradiography after ³H-leucine administration and furnish interesting additional data. The trypan blue-induced fluorescence method gives a good indication of the permeability of the oocytal cortex and its derivative the germinal disc. The avian yolk which is, or has been peripherally assembled (primordial, true white and yellow yolk) can be characteristically labelled by the administration of trypan blue. The injection of higher, still nontoxic quantities of trypan blue has a prolonged retarding effect and permits the marking of a broader part of the germinal disc or eventually of the blastoderm which develops from it.     

Interactions of γ-immunoglobulins with lipid mono- or bilayers and liposomes. Existence of two conformations of γ-immunoglobulins of different hydrophobicities

Interactions between rabbit-γ-immunoglobulins and model membranes (lipid monalayers, planar lipid bilayers, liposomes) have been investigated. No significant interaction was observed with immunoglobulins. However, immunoglobulins dialysed first vs aqueous buffer having pH 2 or 3 and then dialysed against pH 7 buffer presumably adopt a new conformation which allows their bindings to model membranes. This binding is hydrophobic and the immunoglobulin region interacting with the lipid acyl chains is probably located in the heavy chain, as suggested by labelling in this region by a photosensitive probe previously incorporated into the lipid hydrophobic core. Cleavage at the hinge region by papain or pepsin, or heating above 38°C, induces the loss of the hydrophobic conformation responsible for hydrophobic bindings. The binding capacity of immunoglobulins heated above 38°C is restored after momentary dialysis at pH 2. The possible existence of two Ig isomers is discussed in relation to the mechanism of γ-immunoglobulin passage through the endoplasmic membrane and fixation into the plasma membrane.     

Antibody response in laying hens with small amounts of antigen

Chicken antibodies offer many advantages over the traditional mammalian ones. A laying hen produces large amounts of yolk antibodies and the use of yolk antibodies eliminates the painful procedure of collecting blood from the animal. Thus, the use of chicken antibodies will reduce both the number of animals required to produce antibodies and also animal distress. Chicken antibodies also have several biochemical advantages compared to mammalian antibodies: they often increase the signal and reduce interference in many assays. However, the species chosen for antibody production have usually been mammals. This is probably due to tradition, but also to limited knowledge about the production of chicken antibodies. We studied the immune response in the chicken using small amounts of mammalian antigen, and show that a good immune response can be obtained with 0.1–1.0 μg of bovine serum albumin.     

抗人精子甘露糖受体抗血清对精子穿透实验的影响

目的 研究人精子甘露糖受体(MR)在精卵融合中的作用.方法 用亲合层析法分离纯化的人精子甘露糖受体来免疫Balb/c小鼠得到抗MR抗血清;用抗血清处理顶体反应后的人精子,并进行去透明带金黄地鼠卵的精子穿透实验(SPA),观察其体外受精情况.结果 抗MR抗血清可抑制人精子与去透明带金黄地鼠卵的结合与穿透,使卵子的受精率下降,具剂量依赖性.结论 人精子MR与精卵膜的识别与融合有关.     

Extraembryonic motor activity during the embryogenesis of higher vertebrates

Extraembryonic rhythmic motor activity in higher vertebrates, along with the intrinsic motor activity of the embryo, is important for the normal development of the embryo. This can have different natures in different classes of amniotes (i.e., motor activities of the amnion, yolk sac, and uterus), but these have similar functional importance. This activity changes reproducibly during the process of embryogenesis, providing the optimum conditions for normal embryo development. During embryogenesis, a system for controlling extraembryonic rhythmic motor activity is also formed. There is a trend for the regulation of this activity to become more complex in mammals as compared with birds. Reptiles have received little study from this point of view. In addition to regular changes in extraembryonic rhythmic motor activity during embryogenesis which depend on the developmental stage of the embryo, motor activity can also change in response to changes in a number of environmental factors (for example, temperature and the gas composition of the air). This demonstrates the possible involvement of embryo-associated extraembryonic motor activity in adapting the embryo to changing environmental conditions and maintaining homeostasis for the development of the embryo itself. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 84, No. 10, pp. 961–968, October, 1998.     

抗内毒素Fab'的制备

目的 研究抗内毒素卵黄免疫球蛋白(IgY)的活性片断Fab',探讨防治内毒素血症的新途径.方法 用内毒素(LPS)作为抗原免疫25周龄德国罗曼鸡,改良水溶法提取抗内毒素IgY,胃蛋白酶切后提取Fab'片断,光密度法测抗内毒素Fab'的浓度和含量、ELISA检测抗内毒素Fab'效价、SDS-聚丙烯酰胺凝胶电泳检测其分子量及纯度. 结果 抗内毒素Fab'含量为4.2 mg/mL蛋黄液,效价为1∶51 200,纯度为92%,相对分子质量为44 000. 结论 抗内毒素Fab'产量大、效价高、特异性强.     

Fluid compartments of the embryonic environment

The exocoelomic cavity was probably the last remaining physiological body fluid cavity to be explored in the human embryo. Its unique anatomical position has enabled us to study the protein metabolism of the early placenta and secondary yolk sac and to explore materno-embryonic transfer pathways. The exocoelomic cavity forms inside the extraembryonic mesoderm alongside the placental chorionic plate and is now believed to be an important transfer interface and a reservoir of nutrients for the embryo. Maternal or placental proteins filtered in the extraembryonic coelomic cavity are probably absorbed by the secondary yolk sac which is directly connected with the primitive digestive system throughout embryonic development. Protein electrophoresis has shown that the coelomic fluid results from an ultrafiltrate of maternal serum with the addition of specific placental and secondary yolk sac bioproducts demonstrating that the exocoelomic cavity is a physiological liquid extension of the early placenta. The selective sampling of fluid from the exocoelomic cavity has also offered a novel approach to the study of drug and toxin transfer across the early human placenta and as a unique tool to explore embryonic physiology in vivo. Further investigation should include a comparison between the coelomic fluid values of a molecule and its quantifiable presence in decidual, placental and fetal tissues.     

Major phospholipids and phosphatidylcholine synthesis in adult Schistosoma mansoni

The major phospholipids present in the phospholipid extract of Schistosoma mansoni were phosphatidylcholine (28%), phosphatidylethanolamine (25%), phosphatidylserine (15%) and phosphatidylglycerol (8%). The synthesis of phosphatidylcholine in S. mansoni adults occurred by the choline to phosphatidylcholine or Kennedy pathway. Incorporation of CDPcholine and choline into the phosphatidylcholine of worm slices appeared linear over time with no demonstrable sex differences in choline incorporation. A slight difference in the incorporation of CDPcholine by separate sexes was evident. Methylation of phosphatidylethanolamine to phosphatidylcholine could not be demonstrated.     

Egg-sharing in assisted conception: ethical and practical considerations

The present acute shortage of eggs for donation cannot be overcomeunless adequate guidelines are set to alleviate the anxietiesregarding payments, in cash or kind, to donors. The currentHuman Fertilisation and Embryology Authority (HFEA) guidelinesdo not allow direct payment to donors but accept the provisionof lower cost or free in-vitro fertilization (IVF) treatmentto women in recognition of oocyte donation to anonymous recipients.Egg-sharing achieved in this way enables two infertile couplesto benefit from a single surgical procedure. However, the practicalguidelines related to this approach are ill-defined at the presenttime leading to some justifiable uncertainty. A pilot studywas therefore undertaken in order to establish the place ofegg-sharing in an assisted conception programme. The currentHFEA guidelines on medical screening of patients, counselling,age and rigid anonymity between the donor and recipient werefollowed. The study involved 55 women (25 donors and 30 recipients)in 73 treatment cycles involving fresh and frozen-thawed embryos.Donors were previous IVF patients who, regardless of their abilityto pay, shared their eggs equally with matched anonymous recipients.They paid only for their consultations and tests right up tothe point of being matched with a recipient The sole recipientpaid the cost applicable in egg donation of a single egg collection,although both received embryo transfers. The results indicatethat although the recipients were older than the donors (41.4± 0.9 versus 31.6 ± 0.5 years), and there wasno difference in the mean number of eggs allocated, the percentagefertilization rates, or the mean number of embryos transferred,there were more births per patient amongst recipients than amongstdonors (30 versus 20%). We conclude that providing the donorsare selected carefully, this scheme whereby a sub-fertile donorhelps a sub-fertile recipient is a very constructive way ofsolving the problem of the shortage of eggs for donation. Thereare also the advantages of including a group of women who wouldotherwise be denied treatment Problems related to ‘patientcoercion’ can, in our view, be fully overcome by the applicationof strict common-sense safeguards. The ideal of pure altruismis not without its medical and moral risk. The success of egg-sharingdepends on shared interests and a degree of altruism betweenthe donor, the recipient and the centre. The current HFEA guidelinesshould be applauded for enabling a highly effective conceptof mutual help to develop.     

Effect of Phosphatidylcholine Liposome on Regeneration of Surgical Wound in Guinea Pig Lung

Phosphatidylcholine liposomes in a dose of 25 mg/kg displayed wound-healing properties. They increased the count of alveolar macrophages, lymphocytes, and microvessels in damaged regions and, therefore, attenuated emphysematous changes in the lungs.