Raymond W. Wright

Bio: Raymond W. Wright is an academic researcher from Washington State University. The author has contributed to research in topics: Sperm & Blastocyst. The author has an hindex of 31, co-authored 94 publications receiving 3165 citations.

Aspects of in vitro fertilization and embryo culture in domestic animals.

Abstract: Summary Various aspects of the major components of in vitro fertilization and embryo culture in domestic farm animals are discussed. An examination of the spermatozoa and oocyte incubation media showed no media or protein supplement to be superior in promoting in vitro fertilization in cattle, sheep or swine. Generally, ovulated oocytes or activated follicular oocytes were penetrated by sperm more frequently than were immature oocytes. Spermatozoa that were incubated in vivo or in the oviducts of a different species generally achieved higher oocyte penetration than did spermatozoa incubated in vitro. In most in vitro fertilization studies, an in vivo component was introduced, generally oocyte or sperm maturation, which served to confound analysis of the in vitro results. Furthermore, the relatively low level of success and high incidence of chromosomal abnormalities with in vitro fertilization in other species require that careful and complete studies analyzing the components of in vitro fertilization in domestic farm animals be conducted. The culture of embryos from domestic farm animals is detailed, with emphasis on in vitro conditions and rate of success. As with laboratory animals, bovine, ovine, porcine and caprine embyos of fewer than eight cells are more difficult to culture to the blastocyst

Lipoproteins, cholesterol homeostasis and cardiac health.

Abstract: Cholesterol is an essential substance involved in many functions, such as maintaining cell membranes, manufacturing vitamin D on surface of the skin, producing hormones, and possibly helping cell connections in the brain. When cholesterol levels rise in the blood, they can, however, have dangerous consequences. In particular, cholesterol has generated considerable notoriety for its causative role in atherosclerosis, the leading cause of death in developed countries around the world. Homeostasis of cholesterol is centered on the metabolism of lipoproteins, which mediate transport of the lipid to and from tissues. As a synopsis of the major events and proteins that manage lipoprotein homeostasis, this review contributes to the substantial attention that has recently been directed to this area. Despite intense scrutiny, the majority of phenotypic variation in total cholesterol and related traits eludes explanation by current genetic knowledge. This is somewhat disappointing considering heritability estimates have established these traits as highly genetic. Thus, the continued search for candidate genes, mutations, and mechanisms is vital to our understanding of heart disease at the molecular level. Furthermore, as marker development continues to predict risk of vascular illness, this knowledge has the potential to revolutionize treatment of this leading human disease.

Quantitative determination of the pentose phosphate pathway in preimplantation mouse embryos.

Abstract: A quantitative calculation was made of the pentose phosphate pathway (PPP) activity in preimplantation mouse embryos from the 2-cell through the late blastocyst stage. This activity varied with development and showed repeated high and low values. Peak activities occurred at both the 2-cell (15.8%) and compacted morula (13.6%) stages, with lowest activity at the development of the late blastocyst (3.2%). The metabolic effectors dimitrophenol (DNP) and phenazine ethosulfate (PES) had opposite effects on PPP activity. Dinitrophenol, although stimulating total CO2 production, virtually eliminated PPP activity while PES stimulated the pentose cycle activity 6-fold. These results indicated that the PPP was under metabolic control and that the embryos had a potential for much larger PPP activities. There was no correlation between the C-1/C-6 ratio obtained from the metabolism of [1-14C] and [6-14C] glucose and calculated PPP activities. A metabolic incubation chamber was devised for these experiments that exhibited certain unique features, including continuous collection of 14CO2 and 3H2O. Single embryos were placed in the chamber and sampled momentarily for metabolic activity. Subsequently, such embryos were successfully transferred to pseudopregnant recipients.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Open Pulled Straw (OPS) vitrification: a new way to reduce cryoinjuries of bovine ova and embryos.

Abstract: Although cryopreservation of certain mammalian embryos is now a routine procedure, considerable differences of efficiency exist depending on stage, species and origin (in vivo or in vitro produced). Factors that are suspected to cause most of these differences are the amount of the intracellular lipid droplets and the different microtubular structure leading to chilling injury as well as the volume/surface ratio influencing the penetration of cryoprotectants. A new approach, the Open Pulled Straw (OPS) method, which renders very high cooling and warming rates (over 20,000°C/min) and short contact with concentrated cryoprotective additives (less than 30 sec over −180°C) offers a possibility to circumvent chilling injury and to decrease toxic and osmotic damage. In this paper we report the vitrification by the OPS method of in vitro produced bovine embryos at various stages of development. Embryos cryopreserved from Day 3 to Day 7 (Day 0 = day of fertilization) exhibited development into blastocysts at rates equivalent to those of control embryos; even those cryopreserved on Day 1 or 2 exhibited only somewhat reduced survival. Eighty-one percent of Day 8 hatched blastocysts also survived the procedure. The method was also successfully used for bovine oocytes; of 184 vitrified oocytes, 25% developed into blastocysts after fertilization and culture for 7 days. Pregnancies were achieved following transfer after vitrification at both the oocyte and blastocyst stage. The OPS vitrification offers a new way to solve basic problems of reproductive cryobiology and may have practical impact on animal biotechnology and human assisted reproduction. Mol. Reprod. Dev. 51:53–58, 1998. © 1998 Wiley-Liss, Inc.

Sperm transport in the female reproductive tract

Abstract: At coitus, human sperm are deposited into the anterior vagina, where, to avoid vaginal acid and immune responses, they quickly contact cervical mucus and enter the cervix. Cervical mucus filters out sperm with poor morphology and motility and as such only a minority of ejaculated sperm actually enter the cervix. In the uterus, muscular contractions may enhance passage of sperm through the uterine cavity. A few thousand sperm swim through the uterotubal junctions to reach the Fallopian tubes (uterine tubes, oviducts) where sperm are stored in a reservoir, or at least maintained in a fertile state, by interacting with endosalpingeal (oviductal) epithelium. As the time of ovulation approaches, sperm become capacitated and hyperactivated, which enables them to proceed towards the tubal ampulla. Sperm may be guided to the oocyte by a combination of thermotaxis and chemotaxis. Motility hyperactivation assists sperm in penetrating mucus in the tubes and the cumulus oophorus and zona pellucida of the oocyte, so that they may finally fuse with the oocyte plasma membrane. Knowledge of the biology of sperm transport can inspire improvements in artificial insemination, IVF, the diagnosis of infertility and the development of contraceptives.

Low O2 tensions and the prevention of differentiation of hES cells

Abstract: Early-stage mammalian embryos develop in a low O2 environment (hypoxia). hES cells, however, are generally cultured under an atmosphere of 21% O2 (normoxia), under which conditions they tend to differentiate spontaneously. Such conditions may not be the most suitable, therefore, for hES cell propagation. Here we have tested two hypotheses. The first hypothesis was that hES cells would grow as well under hypoxic as under normoxic conditions. The second hypothesis was that hypoxic culture would reduce the amount of spontaneous cell differentiation that occurs in hES colonies. Both hypotheses proved to be correct. Cells proliferated as well under 3% and 5% O2 as they did under 21% O2, and growth was only slightly reduced at 1% O2. The appearance of differentiated regions as assessed morphologically, biochemically (by the production of human chorionic gonadotropin and progesterone), and immunohistochemically (by the loss of stage-specific embryonic antigen-4 and Oct-4 and gain of stage-specific embryonic antigen-1 marker expression) was markedly reduced under hypoxic conditions. In addition, hES cell growth under hypoxia provided enhanced formation of embryoid bodies. Hypoxic culture would appear to be necessary to maintain full pluripotency of hES cells.