bluuebunny/crossref_metadata_2025 huggingface dataset:
Biopotency in vitro and metabolic clearance rates of five pituitary preparations of follicle stimulating hormone
Authors: Phillips DJ , Hudson NL , Lun S , Condell LA , McNatty KP
Published: October 2005

Five pituitary preparations of follicle stimulating hormone (FSH), namely NIDDK-oFSH-17, Bioscan oFSH, Ovagen, Folltropin-V and F.S.H.-P., were examined for biological activity in terms of their potency in an in vitro bioassay, receptor assay and heterologous radioimmunoassay and in terms of their metabolic clearance rates. In the three assays, Bioscan oFSH was the most potent (P < 0.05) (3- to 5-fold the potency of NIDDK-oFSH-17), with Ovagen being 25-50% the potency of the NIDDK standard (P < 0.05). Folltropin-V and F.S.H.-P. had the lowest potencies in all three assays. For each preparation, the ratio of activities between the assays was not consistent, suggesting that the preparations behaved differently in each assay. In 9 of 10 cases, potency estimates in the heterologous radioimmunoassay were greater than those in the in vitro bioassay or receptor assay. Polyacrylamide gel electrophoresis of the preparations showed banding consistent with the molecular weight of FSH, but also indicated that the preparations were contaminated with other proteins to varying extents. The half-lives of these preparations when injected into the bloodstream of mature female mice were 28.0, 8.6, 13.4, 11.6 and 17.4 min for NIDDK-oFSH-17, Bioscan oFSH, Ovagen, Folltropin-V and F.S.H.-P. respectively. The slopes of the decay rates were significantly different from each other (P < 0.05) except between Ovagen and Folltropin-V. The results of these studies show that a number of widely available FSH preparations have differing biopotencies. Moreover, the biopotency of a preparation in vitro is not related to its metabolic clearance rate, and not all FSH preparations behave identically in different assays. Measures of biopotency in vitro combined with those of metabolic clearance rate may provide useful information on the properties of FSH preparations used for research purposes and for superovulation of farmed livestock.
Binding sites for interferons on ovine and human endometrial membranes
Authors: Russell DL , Manalo GG , Findlay JK , Salamonsen LA
Published: October 2005

In the ewe, the major product of the preimplantation blastocyst is ovine trophoblast protein-1 (oTP-1), which is now classified as an omega-interferon (IFN). Receptors for IFN are present on sheep endometrium and vary cyclically, presumably modified by the actions of ovarian steroids. This study examined whether or not IFN receptors were present on human endometrium at any stage during the menstrual cycle. In addition, the steroid dependence of ovine endometrial IFN receptors was determined. Specific binding of 125I-labelled IFN (125I-IFN) to ovine endometrial membranes was substantially higher than binding to membranes derived from bovine spleen, human placenta or pooled human endometrium (relative specific binding 100:33:36:20). Human endometrial membrane preparations from proliferative-phase tissue showed very little specific binding (mean 0.8 +/- 0.3%, n = 4) in contrast to luteal-phase endometrium (2.1 +/- 0.3%, n = 8). Treatment of ovariectomized ewes with oestradiol-17 beta (E) resulted in significantly increased binding (117 +/- 7%) of 125I-IFN to endometrial tissues compared with tissue from ovariectomized (OvX, 75 +/- 7%), progesterone (P)-treated (69 +/- 7%), or (E + P)-treated (81 +/- 8%) groups (P < 0.05); all were compared with binding to pooled ovine luteal-phase tissue, 100%. There were no differences between the other three groups. Scatchard analysis showed binding affinity of the same order for the sheep and human receptors (Kd = 10(-10) mol L-1) but binding capacity was considerably lower for human (6.0 fmol mg-1) than for sheep (47-123 fmol mg-1) endometrium.(ABSTRACT TRUNCATED AT 250 WORDS)
Reproductive cycles and pregnancy in interspecific sheep<==>goat chimaeras
Authors: MacLaren LA , Anderson GB , BonDurant RH , Edmondson AJ
Published: October 2005

The objectives of the current study were to determine whether interspecific sheep<==>goat chimaeras exhibited reproductive cycles of their component species and were capable of maintaining ovine and caprine pregnancies to term. All chimaeras had oestrous cycles and several exhibited characteristics of both ewes and does, including short, 6-7-day cycles. Sixteen caprine pregnancies were confirmed in eight sheep<==>goat and one hybrid<==>sheep chimaera from 21 embryo transfers; of these, six appeared normal by ultrasonographic examination during Weeks 5 or 6, but none progressed beyond Week 8. Three apparent pseudopregnancies developed in two animals. In contrast, eight of 11 pregnancies in chimaeras resulted in term ovine offspring after transfer of ovine embryos or natural matings with rams. By comparison, interspecific (caprine or hybrid) pregnancies in ewes were lost in Week 4 (n = 8) or Weeks 5-6 (n = 2). First interspecific (ovine or hybrid) pregnancies in does were maintained longer (Weeks 6-12, n = 7) than second interspecific pregnancies (Weeks 4-5, n = 5) (P < 0.05) or interspecific pregnancies in ewes (P < 0.05). The results suggest that abnormal fetomaternal interactions during the early stages of implantation are responsible for termination of caprine pregnancies in the ovine or chimaeric uterus, whereas ovine conceptuses are able to implant successfully in the chimaeric uterus. All chimaeras were fertile, since each carried at least one ovine pregnancy to term following natural matings with rams.
Prostaglandin production by the oocyte cumulus complex around the time of fertilization and the effect of prostaglandin E on the development of the early bovine embryo
Authors: Gurevich M , Harel-Markowitz E , Marcus S , Shore LS , Shemesh M
Published: October 2005

The oocyte-cumulus complex (25 oocytes per 250 microL medium) produced prostaglandin-F2 alpha (PGF2 alpha) and PGE2 during maturation, immediately following fertilization and for at least 48 h after fertilization. The data suggest that PG production is important in the development of the oocyte; addition of PGE2 (5 ng mL-1) to the fertilization medium increased the rate of cleavage and groups of oocytes with low cleavage rates produced far less PG than groups with high cleavage rates. Measurement of PG in the maturation medium could therefore be a means of assessing the suitability of oocytes for fertilization.
Contribution of the pentose phosphate pathway to glucose utilization by preimplantation sheep embryos
Authors: Wales RG , Du ZF
Published: October 2005

The activity of the pentose phosphate pathway of glucose metabolism in early sheep embryos and in the structures of the advanced conceptus from Day 13 to Day 19 of pregnancy was measured quantitatively during a 2.5-h incubation with glucose as sole energy source. For embryos during cleavage, activity of this pathway accounted for 6-9% of total glucose utilized. The proportion of glucose metabolized through the pentose pathway fell progressively with development and by Day 19 represented 1-2% of glucose turnover. However, total turnover of glucose increased eight fold between the 2-cell and blastocyst stage and the amount of glucose processed through the pentose pathway increased over this time despite the fall in the proportion utilized in this way. In contrast, glucose turnover by the advanced embryo and its extra embryonic membranes progressively decreased as the structures developed. As a result, estimates of the amount of glucose utilized through the pathway per microgram dried weight per hour declined to low values at Day 19 following the peak in activity at about the time of blastulation. Trophoblast and yolk sac processed less glucose through the pentose pathway per microgram dried weight than embryonic tissue but the allantois was similar to the embryo. Overall, the pentose pathway accounted for a relatively constant proportion of the CO2 produced from glucose under these experimental conditions with values generally between 15 and 20% of total CO2 produced. When activities in the components of the advanced conceptus were expressed as the total amount of glucose processed through the pathway per hour, turnover in the embryo, allantois and yolk sac increased progressively with time. By contrast, there was a substantial trough in the activity of the trophoblast on Day 17 of pregnancy.
Congenital absence of vas deferens treated by artificial spermatocele constructed from the tunica vaginalis; report of six cases
Authors: Wen RQ , Li SQ , Li QK , Mei QM , Wang CX , Wang QH , Huang JC
Published: October 2005

Six patients with congenital absence of the vas deferens were treated by artificial spermatoceles (ASCs) in an attempt to collect sperm for subsequent artificial insemination (AI). The ASC was constructed from a flap of tunica vaginalis from the patient. Sperm were aspirated from the ASC each month; there was wide variation in the concentration of sperm recovered [33.0 +/- 48.2 x 10(6) mL-1 (range 0.1-200)] and motility and normal morphology of the sperm were 19.0 +/- 17.9% and 48.8 +/- 23.4% respectively. Although a total of 14 cycles of AI was performed using the aspirated sperm, pregnancy did not result. Both poor sperm recovery and poor motility contributed to this failure. The condition of the epididymis observed during scrotum examination is reported. It is suggested that in some patients with congenital absence of vas deferens, the paired Wolffian ducts may differ from each other in their development.
Glycolysis and glucose oxidation by the sheep conceptus at different oxygen concentrations
Authors: Du ZF , Wales RG
Published: October 2005

The effect of changes in oxygen concentration on the catabolic utilization of glucose by the sheep conceptus at selected periods between Days 3 and 19 of preimplantation development was examined by estimating the production of CO2 and lactate from [U-14C]glucose during a 2.5-h culture in vitro in the presence of 20%, 5% and 1% O2. In general, lowering O2 significantly altered the catabolism of glucose with a changing pattern of response depending on the stage at which the conceptus was explanted. For embryos at Days 3 and 6 post insemination, reduced O2 caused no significant change in oxidative utilization of glucose and a small decrease in conversion of the substrate to lactate. By contrast, lowering O2 concentration during incubation of the structures of the advanced conceptus from Day 13 through to Day 19 of pregnancy significantly restrained oxidative utilization of glucose but stimulated its conversion to lactate. The effects of these changing levels of O2 on the generation of energy from glucose in the form of ATP was estimated. Except for the Day-13 conceptus, reduction in O2 concentration had little influence on the calculated amount of ATP produced from glucose, with glycolysis making up the deficit in energy production when reduced O2 inhibits oxidation of the substrate at the later stages of development. At Day 13, the switch in the metabolism of glucose to glycolysis is not fully effective and energy production fell as O2 concentration was reduced. The results indicate a major shift towards dependence by the preimplantation sheep conceptus on the glycolytic pathway for energy generation from glucose as development progresses. This move to glycolysis is increased by low O2 concentration. As a low concentration of O2 most probably exists in the lumen of the sheep uterus, the results indicate that, in utero, the energy required for the rapid growth of the conceptus depends progressively more on glycolysis than oxidative metabolism of glucose. The finding that the Day-13 conceptus has not fully adapted to this method of ATP generation at low O2 concentrations may make it especially vulnerable during development in utero.
Development of preimplantation guinea-pig embryos in serum-free media
Authors: Suzuki O , Ogura A , Asano T , Noguchi Y , Yamamoto Y , Oike M
Published: October 2005

This study was undertaken to determine how far preimplantation guinea-pig embryos can develop normally in vitro with serum-free media generally used for mouse (Whitten's medium, WM) and rabbit (Kane's medium, KM) embryos. Preimplantation guinea-pig embryos were recovered from naturally mated females at each day of pregnancy between Day 1 and Day 6, and were cultured in vitro with either WM or KM at 37 degrees C in 5% CO2 in air. One-cell (Day-1) and 2-cell (early Day 2) embryos cultured in WM developed to the 4-cell and morulae stages respectively, whereas the corresponding embryos cultured in KM arrested development at the 2-cell and 8-cell stages respectively. In contrast, 4-cell (late Day 2 and Day 3) embryos proceeded to the blastocyst stage in KM, but not in WM. Eight-cell embryos (Day 4) and morulae (Day 5) developed to blastocysts in either medium. However, hatching of the blastocysts and trophoblast outgrowth on the culture dish were supported only by KM even when collected at the blastocyst stage. The present study suggests that, in guinea-pig embryos, a distinct change in nutritional requirements occurs around the time of the second cell division and that, unlike in the mouse, trophoblast outgrowth in the guinea-pig requires no supplementation of serum or extracellular matrices.
Similarity of an oviduct-specific glycoprotein between different species
Authors: Gandolfi F , Passoni L , Modina S , Brevini TA , Varga Z , Lauria A
Published: October 2005

The oviduct provides the best environment in which a zygote can grow and it can also support the development of embryos from a different species. However, there is no clear explanation of its embryotrophic properties at present. In several species, oviduct epithelial cells synthesize and secrete glycosylated proteins that become associated with developing embryos. Although these macromolecules may have a functional role at the time of fertilization and early embryonic development, the nature of such a role remains to be elucidated. The aim of this work was to perform a comparative analysis of oviduct-specific glycoproteins in search of molecules common to different species since their phylogenetic conservation would imply biological significance. In previous studies, sheep oviduct-specific proteins were characterized and a monoclonal antibody (AFRC MAC 264) specific for the sheep oviduct protein 92 (sOP 92) was produced; hence, sheep was taken as the reference species. The degree of similarity between sheep glycoproteins and those of the cow, goat, pig, rabbit and mouse was determined on the basis of: the presence of carbohydrate side-chains, cross-reactivity with AFRC MAC 264, correspondence of molecular weight between cross-reacting molecules, and similarity of immunohistochemical localization. On this basis, proteins similar to sOP 92 were present in cow and goat oviduct. A more limited similarity was also observed in pigs. This indicates a certain degree of phylogenetic conservation and suggests that these molecules may play an important physiological role; however, their function remains to be determined.
Transforming growth factor-alpha: identification in bovine corpus luteum by immunohistochemistry and northern blot analysis
Authors: Lobb DK , Dorrington JH
Published: October 2005

Transforming growth factor-alpha (TGF-alpha), a product of the thecal cells, has potent mitogenic and steroidogenic influences on cells within the ovarian follicle. Whether TGF-alpha continues to be produced in those follicles that go on to ovulate and form a corpus luteum is currently under investigation. In the present study, TGF-alpha was localized in the bovine corpus luteum by means of immunoperoxidase staining using a monoclonal antibody for TGF-alpha that does not cross-react with epidermal growth factor. In corpora lutea from the mid-luteal phase of the cycle TGF-alpha staining was found predominantly in the large luteal cells. Northern blot analysis using a human TGF-alpha cDNA probe hybridized to the 4.5-4.8 kb TGF-alpha transcript in RNA from the corpus luteum. These studies provide new evidence that TGF-alpha, a potent paracrine regulator within the ovarian follicle, continues to be expressed in the corpus luteum.
Determination of porcine endometrial phospholipase A2 activity and detection of immunoreactive cyclooxygenase during the oestrous cycle and early pregnancy
Authors: Dubois DH , Smith LC , Bazer FW
Published: October 2005

Experiments examined the characteristics and activity of phospholipase A2 (PLA2) and examined the presence of immunoreactive cyclooxygenase in endometrium of pigs during the oestrous cycle and early pregnancy. Endometrial PLA2 was calcium-independent and activity of the enzyme was greatest at a pH of 8.0. Activity of PLA2 on Days 10, 12, 14 and 16 of the oestrous cycle did not differ (P > 0.1) from activity on those days during pregnancy. During oestrus and early metoestrus (Days 0-3), cyclooxygenase was present in both glandular and surface epithelium. After Day 10 of the oestrous cycle or pregnancy, staining for cyclooxygenase was less intense in the lower and middle uterine glands. However, the upper glandular epithelium near the surface epithelium stained intensely. By Day 15 of the oestrous cycle or pregnancy, intense staining for cyclooxygenase appeared restricted to the upper uterine glands. These results indicate changes in localization of immunoreactive cyclooxygenase throughout the oestrous cycle and suggest that these are not related to altered secretion of prostaglandins (PGs) during early pregnancy. The stimulatory effects of porcine conceptus products on secretion of PGs during early pregnancy are apparently not associated with increased activity of endometrial PLA2.
Forty years of control of the oestrous cycle in ruminants: progress made, unresolved problems and the potential impact of sperm encapsulation technology
Authors: Jochle W
Published: October 2005

Pharmacological control of the oestrous cycle may, with or without sperm encapsulation, remain an indispensable part of any attempt to make artificial insemination available to the ranch-cattle industry. Of the current methods, those most likely to remain acceptable with regulatory agencies and to gain acceptance with industry are those involving the short-term use (7-10 days) of minimal effective doses of progestins (preferably progesterone) and the subsequent use of an analogue of prostaglandin F2 alpha. The use of microencapsulated sperm with a long lifespan would allow artificial insemination to be achieved without reference to the time when heat and ovulation may occur.
Liquid storage of ram semen: a review
Authors: Maxwell WM , Salamon S
Published: October 2005

Research from 1930 to 1992 is reviewed with regard to storage of semen at reduced (0-5 degrees C or 10-15 degrees C) and at ambient temperatures. Diluents investigated have included synthetic buffers combined with sugars and egg yolk or its fractions, milk from various sources, glycine, and other substances. Irrespective of the diluent, dilution rate, temperature or conditions of storage, the spermatozoa deteriorate with time of storage. Changes include reduction in motility and morphological integrity of spermatozoa, accompanied by a decline in their survival in the female reproductive tract, reduction in fertility and increased embryonic loss. In critical studies, fertility declined rapidly when semen stored for more than 24 h was used for cervical insemination, but after intrauterine insemination some spermatozoa maintained their fertilizing capacity up to 10 days. Laparoscopic intrauterine or transcervical inseminations could be the means of improvement of fertility. These methods may eliminate the problem of sperm transport through the cervix and ageing of spermatozoa in the reproductive tract, thereby improving fertilization of ova and reducing embryonic loss.
Lipids and calcium uptake of sperm in relation to cold shock and preservation: a review
Authors: White IG
Published: October 2005

When sperm of the ram, bull, boar and stallion are cold-shocked by rapid cooling to near freezing point, motility and metabolic activity are irreversibly depressed and the acrosome and plasma membrane disrupted. Ram sperm become susceptible to cold shock in the proximal corpus region of the epididymis when the cytoplasmic droplet has moved backwards to the distal portion of the sperm midpiece. The membrane constituents phospholipids and cholesterol are important in cold shock which causes loss of lipid from sperm. The susceptibility of sperm to cold shock is linked with a high ratio of unsaturated:saturated fatty acids in the phospholipids and a low cholesterol content. The high unsaturated fatty acid content of sperm also makes them susceptible to damage from peroxidation which adversely affects motility, metabolism, ultrastructure and fertility. Hydroxynonenal, a product of fatty acid peroxidation, depresses the motility and oxygen uptake of ram sperm in vitro and may react with the -SH groups of the axonemal microtubules. High calcium concentrations in the external medium may decrease the motility and metabolism of sperm and 'calcium intoxication' may be a factor in cold shock. Lowering the environmental temperature increases calcium uptake by sperm and the effect is aggravated if the rate of cooling is rapid. Phospholipids, particularly those in egg yolk, protect sperm to some extent from cold shock and also prevent increased calcium flux into the sperm. Suggestions are made for increasing the life span of sperm during preservation and microencapsulation by adding agents that may stabilize membranes, counter peroxidation and decrease calcium uptake.
Factors affecting preservation and fertility of bull sperm: a brief review
Authors: Foote RH , Parks JE
Published: October 2005

This paper is a brief review of the factors that determine the number of sperm required for insemination to obtain high fertility and ways that sperm viability might be prolonged. Damage to sperm during freezing results in a requirement, after thawing, of about 6 x 10(6) motile sperm (> 10 x 10(6) total) per insemination to achieve near-maximal fertility, whereas 2.5 x 10(6) motile fresh sperm result in high nonreturn rates. Multiple inseminations to bracket the time of ovulation are usually not economical except in superovulated cows. Earlier unpublished work on sperm packaging for slow release in the cow and methods for stabilizing membranes to increase sperm survival time in the cow are discussed. Current studies are directed towards reducing catabolic metabolism of sperm and studying membrane changes during freezing and thawing and during incubation with bovine oviduct epithelial cells. Studies with bull sperm indicate that the choline and ethanolamine phosphoglyceride components of their membranes represent an unstable configuration. Exposure of sperm to liposomes with the sterol cholesterol can alter the phospholipid bilayer and increase capacitation time. Similar approaches may produce sperm with a longer fertilizing life following insemination. New procedures in vitro permit low cost modelling of fertilization, which will facilitate research by reducing the cost of studies in vivo.
Local experience with zona drilling, zona cutting and sperm microinjection
Authors: Payne D , Warnes GM , Flaherty SP , Matthews CD
Published: October 2005

Clinical trials were performed between 1987 and 1992 on the use of zona drilling (ZD), zona cutting (ZC) and subzonal sperm microinjection (SZI) for the treatment of severe male infertility. ZD significantly improved the fertilization rate, but embryo morphology was poor and no pregnancies were achieved, so it was abandoned in favour of ZC. The fertilization rate was acceptable in the first trial of ZC but embryo morphology was still poor and no pregnancies were achieved, so a number of protocol changes were instigated. Shrinkage of oocytes in hypertonic sucrose prior to ZC markedly improved embryo quality, whereas transfer of embryos on Day 3 after oocyte retrieval enhanced the pregnancy rate. However, despite these improvements, the overall pregnancy rate in the third ZC trial was still low (16.6% per transfer), so a trial of SZI was initiated in 1992. The overall fertilization rate in 82 SZI cycles was 34.4% and, although the polyspermy rate was high, a clinical pregnancy rate of 30.8% per transfer and an implantation rate of 18.4% per embryo were achieved. These trials demonstrate that SZI is a successful treatment for severe male infertility; under the trial conditions, at least, it was superior to ZD or ZC.
Injection of multiple sperm into the perivitelline space as a treatment of male infertility
Authors: O'Neill C , Ryan JP , Catt JW , Pike IL , Krzyminska UB
Published: October 2005

This paper reports the outcome of 274 treatment cycles using multiple injection of sperm into the perivitelline space as a treatment of male factor infertility. A total of 170 couples underwent this form of treatment; 59.1% of cycles had at least one oocyte normally fertilized with an overall normal fertilization rate of 17.2%. The development rate of normally fertilized embryos was high (98.5%) and resulted in a pregnancy rate (positive human chorionic gonadotrophin 18 days after embryo transfer) of 21.4% per embryo transfer procedure (a maximum of 3 embryos were transferred per procedure). The relationship between the number of sperm injected and the fertilization rate and other factors affecting the outcome are discussed.
Microinjection: choice of embryo transfer technique
Authors: McLachlan RI , Fuscaldo G , Calderon I , Lacham-Kaplan O , Poulos C , Rho H , Trounson A , Wood C
Published: October 2005

Subzonal sperm microinjection (SUZI) is indicated in severe oligoasthenozoospermia, in which the total count of motile sperm is inadequate for in vitro fertilization (IVF), and in cases with repeated failure of fertilization. Sperm for microinjection are selected following centrifugation on a Percoll gradient and stimulation with pentoxifylline and 2-deoxyadenosine. Motile sperm (2-10 per egg) are injected into the perivitelline space and fertilized oocytes are then cultured for two days prior to transfer into the Fallopian tube (tubal embryo stage transfer, TEST) or uterus. During 1992, SUZI results showed a total fertilization rate of 30% (19% were 2 pronuclear, 11% were polyspermic), a transfer rate of 55% and pregnancy rates of 15.2% per transfer and 8.3% per cycle. Recent pregnancy data in mild-moderate male factor infertility showed that gamete intrafallopian transfer (GIFT) results were consistently superior to TEST or IVF, suggesting a beneficial effect of the tubal environment on fertilization and early embryonic development. Accordingly, the combination of SUZI followed by the immediate transfer of injected oocytes into the Fallopian tube, the MIFT procedure, was explored. An initial study of 21 consecutive microinjection candidates showed a clinical pregnancy rate of 24% per cycle. Information regarding fertilization and polyspermy rates was available from supernumerary oocytes in 90% of patients. A randomized, controlled trial comparing MIFT with SUZI or TEST in severe male factor infertility is required to confirm the improved pregnancy rate in MIFT cycles.
Assisted fertilization by subzonal insemination and intracytoplasmic sperm injection
Authors: Van Steirteghem A , Liu J , Joris H , Nagy Z , Staessen C , Camus M , Wisanto A , Van Assche E , Devroey P
Published: October 2005

The results of 600 consecutive treatment cycles of subzonal insemination (SUZI) and intracytoplasmic sperm injection (ICSI) are described in couples with failed fertilization after standard IVF or insufficient spermatozoa in the ejaculate for IVF. More oocytes were damaged by ICSI (16.3%) than by SUZI (8.5%) and the normal fertilization rate was substantially higher after ICSI (49.1% v. 16.6%). Subsequent development of two-pronuclear oocytes in vitro was 80% after SUZI and 73.9% after ICSI. Significantly more triple embryo replacements were carried out after ICSI than after SUZI. Embryo transfers were possible in 421 of the 600 cycles. There were 63 pregnancies after ICSI (215 transfers) and 23 after SUZI (156 transfers); 10 additional pregnancies were achieved after 50 transfers of a mixture of SUZI and ICSI embryos. The results of fetal karyotypes and follow-up of the children do not indicate an increase in congenital malformations.
Successful embryo transfer following artificial insemination of superovulated fallow deer (Dama dama)
Authors: Jabbour HN , Marshall VS , Argo CM , Hooton J , Loudon AS
Published: October 2005

Thirty-four European fallow deer (Dama dama dama) were randomly allocated into embryo donor (n = 12) or embryo recipient (n = 22) groups. All does were treated with controlled internal drug release (CIDR) devices for 14 days. Animals in the embryo donor group were further treated with 200 I.U. pregnant mare serum gonadotrophin (PMSG) and 0.5 units ovine follicle-stimulating hormone (FSH). PMSG was administered 72 h before withdrawal of CIDR devices and FSH was given in eight 0.063 unit injections at 12-hourly intervals starting at the time of PMSG administration. All embryo donor animals were inseminated, by laparoscopy in both uterine horns, 36 h after withdrawal of CIDR devices with 25 x 10(6) fresh spermatozoa collected from Mesopotamian fallow deer (Dama dama mesopotamica). Embryos were recovered by laparotomy on Day 3 (n = 6) or Day 6 (n = 6) after withdrawal of CIDR devices and the ovarian response was determined. In total, 22 embryos were transferred into the oviduct (2-4-cell stage, n = 14) or uterine horn (morula stage, n = 8) on Day 3 or Day 6 after withdrawal of CIDR devices respectively. The overall means (+/- s.e.m.) of total follicular response and corpora lutea were 24.2 +/- 3.5 and 14.1 +/- 3.6 respectively. The mean number of large unruptured follicles was higher on Day 6 than on Day 3 (13.5 +/- 2.9 v. 6.7 +/- 1.3, P < 0.05). The overall embryo recovery rate was 45.8%. There was no difference in pregnancy rate following transfer of embryos on either Day 3 or Day 6 (7/14 v. 5/8 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Thyroid hormones are required for the expression of seasonal changes in red deer (Cervus elaphus) stags
Authors: Shi ZD , Barrell GK
Published: October 2005

Experiment 1, from 6 July 1990 (winter) to 8 November 1990 (spring), examined the effect of an early elevation of plasma thyroid hormone concentrations on the expression of seasonal changes in 20-month-old stags. Four stags were injected subcutaneously with 1 mg thyroxine (T4) daily, and four with vehicle only. Plasma T4 concentration was elevated by injection of T4; the mean concentration 24 h after injection was 192 +/- 31 nmol L-1 compared with 58 +/- 5 nmol L-1 in controls on 21 September. However, live weight, testicular diameter, plasma testosterone concentration and moulting underwent similar changes in both groups of animals. Experiment 2 tested the hypothesis that thyroid hormones are required for the expression of changes that occur during spring and early summer in red deer stags. Thyroidectomized (THX) stags (n = 4) of mixed age (> 22 months old) were given a replacement dosage of T4 or vehicle only (controls) during spring (from 7 September). T4-treated THX stags underwent testicular regression, antler regeneration and spring moult during spring and early summer (October-December), whereas control THX stags did not display these changes. During spring and summer, T4-treated stags gained more live weight (P < 0.05) than control stags. These results show that, in stags, thyroid hormones are required for the expression of seasonal changes and that these changes are not caused by the seasonal elevation of plasma concentrations of thyroid hormones.
Natural and recombinant bovine interferon tau regulate basal and oxytocin-induced secretion of prostaglandins F2 alpha and E2 by epithelial cells and stromal cells in the endometrium
Authors: Danet-Desnoyers G , Wetzels C , Thatcher WW
Published: October 2005

The effects of bovine interferon tau (IFN tau) and oxytocin on secretion of the prostaglandins PGF2 alpha and PGE2 by epithelial and stromal cells in the endometrium were assessed in two experiments. Endometrial tissues were collected from cyclic cows at Day 15 after oestrus for subsequent isolation of epithelial cells (4 cows) and stromal cells (4 cows). In both experiments, confluent cells were treated with 0, 2, 10 or 50 ng mL-1 natural bovine IFN tau (nbIFN tau) or 0, 0.4, 2, 10, 50 and 250 ng mL-1 recombinant bIFN tau (rbIFN tau). Culture medium was sampled at 24 h. Oxytocin (2.0 x 10(-7) M) or placebo was then added to wells and the medium was sampled 30 and 90 min later. Epithelial cells secreted more PGF2 alpha than stromal cells whereas stromal cells predominantly secreted PGE2. Oxytocin stimulated secretion of PGF2 alpha and PGE2 (P < 0.01) from epithelial cells, but both basal secretion and oxytocin-induced secretion of PGF2 alpha and PGE2 decreased with increasing dose of either nbIFN tau or rbIFN tau (P < 0.01). At comparable doses, rbIFN tau inhibited PGF2 alpha and PGE2 secretion more strongly than did nbIFN tau (either in the absence or the presence of oxytocin). The minimal effective dose of rbIFN tau was 0.4 ng mL-1 and 50% inhibition was obtained with 1 ng mL-1 (0.043 nM). Neither nbIFN tau nor rbIFN tau nor oxytocin altered PGF2 alpha or PGE2 secretion by stromal cells. The results indicate differential prostaglandin responses by the two major endometrial cell types (epithelium and stroma) to regulatory agents such as bIFN tau and oxytocin in cattle. Suppression of prostaglandin secretion by bIFN tau in epithelial cells of endometrial tissue is supportive of an antiluteolytic effect of bIFN tau.
Importance of bicarbonate/CO2 for fertilization of pig oocytes in vitro, and synergism with caffeine
Authors: Suzuki K , Ebihara M , Nagai T , Clarke NG , Harrison RA
Published: October 2005

Fertilization of pig oocytes was performed in vitro in modified Tyrode's media in which either HEPES or bicarbonate/CO2, or both, were included as buffer systems; caffeine (2 mM) was also included in some of the media because it is a reported stimulant of fertilization. The composition of the bicarbonate-containing media was designed so as to maintain the same pH and osmolality as bicarbonate-free media. The inclusion of bicarbonate during gamete co-incubation in caffeine-containing medium led to high levels of fertilization (66% of 238 mature oocytes were fertilized). However, essentially no fertilization occurred if bicarbonate was replaced with HEPES (0.7% of 146 oocytes were fertilized; significantly different, P < 0.001). Inclusion of HEPES in bicarbonate-containing medium during gamete co-incubation did not affect fertilization, showing that HEPES did not exert an inhibitory effect. Omission of bicarbonate during sperm preincubation also did not affect fertilization. If caffeine was included in bicarbonate-containing medium, 73% of 311 oocytes were fertilized whereas if caffeine was omitted only 14% of 326 oocytes were fertilized (significantly different, P < 0.001). In the absence of bicarbonate, when fertilization was very low, caffeine had no stimulatory effect. The results indicate that bicarbonate is essential for pig fertilization in vitro, but that caffeine exerts a synergistic stimulatory effect.
Effect of a new anti-oestrogen and anti-implantation agent, CDRI-85/287, on tubal transport, development and viability of rat embryos
Authors: Sreenivasulu S , Singh MM , Kamboj VP
Published: October 2005

The effect of CDRI-85/287, a pure nonsteroidal anti-oestrogen, on the rate of tubal transport and development and viability of embryos in rats was investigated. Single postcoital oral administration of an anti-implantation dose (2.5 mg kg-1) resulted in a mild acceleration in the passage of embryos through the oviduct; however, their rates of recovery, cleavage, blastocyst formation and zona shedding remained unaffected. Morphologically normal embryos were recovered from the genital tract up to Day 12 post coitum. Embryos recovered from CDRI-85/287-treated rats on Days 4 and 8 post coitum developed to normal term fetuses when transferred to uteri of untreated females. The compound therefore did not seem to have any deleterious direct effect on development or viability of rat embryos.
Superovulation and embryo recovery in ewes treated with gonadotrophin-releasing hormone agonist and purified follicle-stimulating hormone
Authors: Evans G , Brooks J , Struthers W , McNeilly AS
Published: October 2005

Chronic treatment with gonadotrophin-releasing hormone (GnRH) agonist eliminates luteinizing hormone (LH) pulses and inhibits maturation of Graafian follicles in sheep. Since the presence of 'dominant' follicles may inhibit superovulatory responses, an experiment was conducted to determine whether a GnRH agonist could be used in conjunction with follicle-stimulating hormone (FSH) to induce a superovulatory response with production of normal embryos. Twenty-four Welsh Mountain ewes were chronically treated with GnRH agonist by means of a subcutaneous minipump. Twelve of the ewes were given 12 mg progesterone intramuscularly (i.m.) twice daily for four days; all ewes were then given 672 micrograms (total) of highly purified FSH continually infused intravenously for either 72 h (Group A) or 96 h (Group B) in a 2 x 2 experimental design (n = 6). Ovulation was then induced with 750 I.U. human chorionic gonadotrophin injected i.m. (Day 0) and all ewes were inseminated into the uterus with > 100 x 10(6) fresh sperm on Day 0. Embryos were flushed from the uterus, and ovaries were inspected at laparotomy on Day 5. Pretreatment with progesterone did not affect any of the parameters measured and data were pooled accordingly. There were no differences between Groups A and B in the number of ovulations or the number of embryos recovered, although there were more large unruptured follicles in Group A animals (8.8 +/- 0.8 v. 3.1 +/- 0.7, P < 0.001). The embryo recovery rate was higher in Group A ewes (52.5 v. 26.4, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Influence of day-0 and day-7 superovulated cow serum during development of bovine oocytes in vitro
Authors: Boediono A , Takagi M , Saha S , Suzuki T
Published: October 2005

Oocytes were matured in medium supplemented with 5% serum collected from superovulated cows at oestrus (Day-0 SCS) or at the time of embryo collection (Day-7 SCS), or in medium supplemented with fetal calf serum (FCS). After insemination using frozen-thawed sperm, oocytes were cultured in vitro with medium supplemented with 5% Day-0 SCS or 5% Day-7 SCS or 5% FCS. The proportions of embryos that cleaved were not significantly different among treatments, whereas development of the embryo to a blastocyst was significantly higher in the presence of SCS than FCS. When the four possible combinations of Day-0 SCS and Day-7 SCS were used in the maturation and culture media, there were no differences among treatments, except that the cleavage rate was significantly higher (P < 0.05) with Day-0 SCS in the maturation medium and Day-7 SCS in the culture medium than with Day-7 SCS in the maturation medium and Day-0 SCS in the culture medium. The proportions of embryos that cleaved and developed to blastocysts were not related with the level of progesterone and luteinizing hormone in the serum added to the maturation and culture media. However, the use of serum with low concentrations of glucose, fatty acids and cholesterol in the maturation medium and the culture medium tended to be associated with a higher rate of cleavage and blastocyst development.
Experimental strategies for the development of an immunocontraceptive vaccine for the European red fox, Vulpes vulpes
Authors: Bradley MP
Published: October 2005

The development of an immunocontraceptive vaccine to control fox populations in Australia would confer considerable advantages in controlling the long-term impact of this predator on native and endangered species. Studies are currently under way to identify sperm antigens that might be used in such a vaccine, and some of these studies are described. It is proposed that such a vaccine would be delivered orally in a bait, thereby stimulating a mucosal immune response to the foreign antigen(s). Such a vaccine requires a detailed understanding of reproductive-tract mucosal immunity in foxes, and selection of the most effective form of antigen delivery. Those under consideration include viral or bacterial vectors and microencapsulated antigens.
Biology and structure of the zona pellucida: a target for immunocontraception
Authors: Epifano O , Dean J
Published: October 2005

Although reversible interference of sperm-egg interactions with pharmacological agents has not yet been achieved, animal models have provided increasing evidence that immunological reagents directed against mammalian gametes can effectively inhibit fertilization. One potential target of immunocontraception is the zona pellucida, an extracellular matrix that surrounds the growing oocyte and ovulated egg. Recent advances in our knowledge of the biosynthesis and molecular biology of the zona pellucida have provided much information useful in the rational design of immunocontraceptive vaccines. There remain, however, major obstacles to using immunological reagents to prevent fertilization, including potential toxic side effects, the lack of adequate delivery systems and the possibility of incomplete reversibility. This review summarizes current understanding of the production of the zona pellucida during folliculogenesis, the structure of the conserved proteins and genes in the zona pellucida, and the progress made in the development of immunocontraceptive strategies that focus on this oocyte-specific structure.
Cytokine regulation of mucosal responses: a rational basis for new vaccine delivery strategies
Authors: Husband AJ , Bao S , Muir W , Ramsay AJ , Ramshaw IA
Published: October 2005

In this review, cytokine regulation of mucosal responses is discussed in relation to the mucosal immune network and regulation of IgA responses. Based on this understanding, aspects of gene therapy for manipulation of the host environment and vaccine delivery systems are discussed. Although evidence obtained in vitro is briefly reviewed the general focus of this article is on evidence obtained from models in vivo.
Comparative structure and function of marsupial spermatozoa
Authors: Temple-Smith PD
Published: October 2005

Marsupial sperm structure has been the focus of many comparative studies in the last 30 years. Although the basic organization of the marsupial spermatozoon is similar to that of eutherian mammals, spermatozoa from this branch of therian evolution have developed a specific suite of characters which clearly distinguish them from the Eutheria. This review surveys these specializations and examines current knowledge on their respective functions and the forces which shaped their evolution. Nuclear shaping and stability, the asymmetric positioning of the acrosome, and the unusual neck articulation are discussed. Although recent observations have provided evidence of a marsupial equatorial segment and posterior ring, the marsupial equivalent of the eutherian postacrosomal sheath has not been identified. The unusual neck structure of marsupial spermatozoa and the mobile articulation of the connecting piece are discussed in relation to nuclear rotation and the events associated with this process. Increasing flagellar length in some species is associated with extremes in flagellar organization and its effect on sperm motility is discussed.
How does sperm meet egg?--in a marsupial
Authors: Breed WG
Published: October 2005

Australian marsupials exhibit a wide range of variation in sperm head morphology, and in thickness of the zona pellucida around the oocyte, suggesting interspecfic differences in the processes of sperm-egg interaction. The observations described here are largely based on the dasyurid Sminthopsis crassicaudata. They show that in oestrous females, after mating, a coagulum forms in the lateral vaginae and, within an hour of insemination, numerous spermatozoa congregate in the isthmus of the oviduct in which the vanguard population undergoes transformation with the head rotating on its axis with the tail to form a T-shape. Once oocytes are released, a few spermatozoa migrate to the higher reaches of the oviduct where sperm-zona binding occurs by way of the plasmalemma over the acrosomal region. The acrosome reaction takes place here and, as the egg rotates, the tail of the spermatozoon becomes parallel to the head. A small region of acrosome sometimes appears to remain intact at this time because spermatozoa with partly intact acrosomes have been found within the zona matrix. In some of these, electron-dense bridges between part of the inner and outer acrosomal membranes which may act as stabilizing structures, were also seen. The zona matrix is tightly packed around the penetrating spermatozoon, but that close to the acrosomal region becomes less electron-dense and more filamentous. Once incorporated into the egg, the spermatozoon lacks a cell membrane around the tail but vesicles close to the sperm head may, at least in part, be remnants of an inner acrosomal membrane. How generally applicable these observations are to other Australian marsupials remains to be determined.
Development of early cell lineages in marsupial embryos: an overview
Authors: Selwood L
Published: October 2005

All major embryonic and extra-embryonic cell lineages are established before implantation in marsupials. In reptiles, birds, monotremes and most marsupials, the zygote is polarized, sometimes markedly so, and the cleavage pattern in relation to the polarized state provides the mechanism for the generation of positional signals. These ensure that the embryonic cell lineages develop in the centre of the developing blastoderm or blastocyst epithelium and the extra-embryonic lineages at the periphery. The evolution of the vertebrate yolky egg was accompanied by a decreasing dependence on maternal determinants and increasing dependence on positional signals to determine cell fate. It is proposed that when a less yolky egg evolved, the mechanisms for determination of cell fate in a developing epithelium were retained. It is proposed that in marsupials, positional signals are involved in the determination of cell fate of embryonic and trophectoderm cells but do so in a two-dimensional epithelium not a three-dimensional morula. The next lineage formed is the primary endoderm which separates off from the primitive ectoderm in the embryoblast and eventually lines the blastocyst cavity. Positional signals are responsible for the determination of primary endoderm in eutherian mammals, birds and probably also marsupials. Order of cell division during cleavage provides a mechanism whereby some cells in the embryoblast of marsupials have earlier and greater contact with their neighbouring cells. The mechanism for determination of primary endoderm cells in the blastocyst epithelium is examined in the Virginia opossum and the stripe-faced dunnart.
Strategies for production of pharmaceutical proteins in milk
Authors: Wilmut I , Whitelaw CB
Published: October 2005

Although it is only a decade since the use of transgenic livestock for the production of pharmaceutical proteins in milk was first suggested, great progress has been made. There is every reason to expect that, as methods for the transfer of genomic clones are applied with efficient regulatory elements, many proteins will be produced at high concentrations in the milk of livestock species. In most cases, these proteins will be biologically active, however, it remains to be shown whether they will be identical in structure and function to the natural product.