bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of polarization reversal on localized-absorption characteristics of electron cyclotron wave in bounded plasmas
Authors: Takahashi K. , Kaneko T. , Hatakeyama R.
Published: October 2005

Propagation and absorption of electron cyclotron wave are investigated for the case in which a left-hand polarized wave (LHPW) is selectively launched in inhomogeneously magnetized and bounded plasmas. The LHPW is observed to be unexpectedly and sharply absorbed near the electron cyclotron resonance point. The unexpected absorption of the LHPW is clarified to be caused by a polarization reversal from the LHPW to a right-hand polarized wave. It is found that the polarization reversal point dominates the absorption region of the electron cyclotron wave, which is observed to be changed by controlling the plasma radius, i.e., radial boundary condition. These phenomena can be well explained in terms of the dispersion relation in bounded plasmas.
Room-temperature reproducible spatial force spectroscopy using atom-tracking technique
Authors: Abe M. , Sugimoto Y. , Custance O. , Morita S.
Published: October 2005

A method for reproducible site-specific force spectroscopic measurements using frequency modulation atomic force microscopy at room temperature is presented. The stability and reproducibility requirements, fulfilled so far only in cryogenic environment, are provided through the compensation of the thermal drift using the atom-tracking technique. The method has been tested performing spectroscopic measurements on atomic positions of the Si(111)-(7×7) surface with Si tips. The room-temperature results presented here compare in quality to previously reported quantitative force spectroscopic data obtained at cryogenic temperatures.
Direct velocity measurements of the flow past drag-reducing ultrahydrophobic surfaces
Authors: Ou Jia , Rothstein Jonathan P.
Published: October 2005

A series of experiments are presented which study the flow kinematics of water past drag-reducing superhydrophobic surfaces. The ultrahydrophobic surfaces are fabricated from silicon wafers using photolithography and are designed to incorporate precise patterns of micrometer-sized ridges aligned in the flow direction. The ridges are made hydrophobic through a chemical reaction with an organosilane. An experimental flow cell is used to measure the velocity profile and the pressure drop as a function of the flow rate for a series of rectangular cross-section microchannel geometries and ultrahydrophobic surface designs. The velocity profile across the microchannel is determined through microparticle image velocimetry (μ-PIV) measurements capable of resolving the flow down to lengthscales well below the size of the surface features. Through these detailed velocity measurements, it is demonstrated that slip along the shear-free air-water interface supported between the hydrophobic micrometer-sized ridges is the primary mechanism responsible for the drag reduction observed for flows over ultrahydrophobic surfaces. A maximum slip velocity of more than 60% of the average velocity in the microchannel is found at the center of the shear-free air-water interface whereas the no-slip boundary condition is found to hold along the surface of the hydrophobic ridges. The experimental velocity and pressure drop measurements are compared to the predictions of numerical simulations and an analytical theory based on a simple model of an ultrahydrophobic surface composed of alternating shear-free and no-slip bands with good agreement.
Structure of finite two-dimensional systems of dust particles at finite temperatures
Authors: Totsuji Hiroo , Totsuji Chieko , Liman M. Sanusi , Tsuruta Kenji
Published: October 2005

The structure of confined two-dimensional systems of dust particles in dusty plasmas is analyzed at finite temperatures by numerical simulations and theoretical approaches. The finite Yukawa system is adopted as a model for these systems and the variational method which has been successful in reproducing structures at low temperatures is extended to finite temperatures through replacement of the cohesive energy by the Helmholtz free energy recently given in the form of simple interpolation formulas. The results are compared with those of numerical simulations and their satisfactory agreement has been obtained. Finite-temperature structures presented here will be useful to evaluate the physical parameters of the two-dimensional systems of dust particles often formed near the boundary between the plasma bulk and the sheath.
Determination of magnetic vortex chirality using lateral spin-valve geometry
Authors: Kimura T. , Otani Y. , Hamrle J.
Published: October 2005

We demonstrate the determination of the vortex chirality using a nonlocal spin-valve measurement technique in a lateral spin valve consisting of a Permalloy (Py) disk 1μm in diameter and a Py wire 100nm in width. The vortex chirality is determined under two probe configurations; the disk as the current probe and the disk as the voltage probe. The vortex chirality is found to depend on the probe configuration because of the current-induced Oersted field.
Investigating the Potential of Key Sectors Using Multisectoral Qualitative Analysis: A Welsh Case Study
Authors: Bryan Jane , Jones Calvin , Munday Max
Published: October 2005

The authors examine the use of multisectoral qualitative analysis (MSQA) for evaluating the potential of key sectors in a regional case. They examine the desirability of policy focusing on the promotion of key sectors. It is suggested that the tools used to identify, and then to justify, key sectors are generally underdeveloped. The authors provide a review of selected methods to identify and classify key growth sectors, and their strengths and weaknesses. Given the weaknesses inherent in these approaches, it is particularly important for policymakers to consider methods which can test and extend key-sector evaluation. The authors suggest that MSQA provides an effective and policy-relevant means of forming conclusions on sector potentials, and report on a pilot exercise undertaken in the Welsh economy.
Providing Enterprise Support for Offenders: Realising New Opportunities or Reinforcing Old Inequalities?
Authors: Fletcher Del Roy
Published: October 2005

Policies to encourage entry into self-employment are increasingly being linked to measures to combat high unemployment and social exclusion. This is particularly evident in the United Kingdom, where a plethora of initiatives to promote enterprise in deprived communities and amongst underrepresented groups have recently been introduced. Drawing upon findings emerging from research conducted for the Small Business Service (SBS), the author discusses the current system of enterprise support for offenders in England. The key finding which emerges is that support is characterised by a number of fundamental weaknesses which risks perpetuating the myth that offenders are natural risk takers capable of turning small amounts of financial capital into thriving businesses, whilst consigning many to insecure, low-paid forms of employment.
Plasma progesterone and body weight in the pregnant and non-pregnant kowari, Dasyuroides byrnei (Marsupialia:Dasyuridae)
Authors: Fletcher TP
Published: October 2005

Female kowaris are seasonal breeders (May-November) with a gestation of 32.5 +/- 1.8 days (mean +/- s.d., n = 35). The oestrus cycle including pregnancy is 59.0 +/- 6.7 days in duration (mean +/- s.d., n = 12) and is not significantly different from the non-pregnant cycle of 60.3 +/- 7.1 days (mean +/- s.d., n = 15) (P greater than 0.1). Animals maintained on a fixed diet show an increase and fall in body weight before oestrus and again at the end of the oestrous cycle or a pregnancy; these changes correlate closely with progesterone concentration. Plasma progesterone concentration and body weight were measured in six kowaris undergoing an oestrous cycle then a pregnancy in the breeding season of 1981. The basal concentration (mean +/- s.d.) of progesterone prior to the breeding season was 0.35 +/- 0.21 ng mL-1. There were mean rises of 1.84 +/- 1.1 and 2.47 +/- 1.5 ng mL-1, respectively, before the first and second oestrous periods which had declined to near basal levels by the day of oestrus. Peak values of 9.9-11.5 ng mL-1 were measured between days 23 and 30 of oestrous cycle and pregnancy. The pattern of changes in body weight and plasma progesterone concentration was similar in pregnant and non-pregnant animals but the decline in weight and progesterone occurred earlier in pregnant kowaris.
Effects of oxygen concentration on the metabolism of
Authors: Khurana NK , Wales RG
Published: October 2005

The utilization of the acid-soluble glycogen pool in pulse-labelled embryos was significantly enhanced during 24- and 48-h chase culture under low oxygen concentrations of 5, 2.5 and 1%. The lower the oxygen tension the greater was the turnover in the pool. The morphological development of embryos was equally as good at very low oxygen concentrations as when embryos were cultured in 5-20% oxygen. Reduction in oxygen concentration enhanced the oxidative utilization of substrate, as measured by rate of carbon dioxide production. The present study could provide an explanation for the discrepancy in glycogen content between mouse blastocysts developing in utero and in vitro and for the reported beneficial effects of low oxygen concentration during development of embryos in culture.
In vivo cleavage rates and viability obtained for early cleavage mouse embryos in co-culture with oviduct cells
Authors: Sakkas D , Trounson AO , Kola I
Published: October 2005

The cleavage rate and development of two-cell mouse embryos to the morulae stage in co-culture with mouse oviduct cells was studied in vitro and compared with those achieved in vivo. Embryos were cultured in Whittingham's T6 (T6), T6 supplemented with fetal calf serum (FCS) and in co-culture with either Dulbecco's Modified Eagles Medium supplemented with sodium lactate (DMEM + 1a) or a modification of T6 medium containing vitamins and amino acids (T6 + v + aa). Co-culture of oviductal cells with DMEM + la medium supported two-cell mouse embryo development to eight cells at a rate significantly better (P less than 0.001) than T6, but the rate of embryo development was not equivalent to that in vivo. DMEM + la alone was inadequate as an embryo culture medium. Co-cultures using T6 + v + aa with mouse oviductal cells were prepared from mice at days 1, 2 or 3 of pseudopregnancy. Day 2 and 3 co-cultures allowed two-cell embryos to develop at a rate comparable to that in vivo up to the mid eight-cell stage (68 h after hCG), but by 76 h after hCG embryos were retarded. Transfer to pseudopregnant recipients of embryos co-cultured with day 2 oviductal cells until 68 h after hCG resulted in a rate of fetal development equivalent to that of embryos grown in vivo. Our results show that co-culture of early cleavage-stage embryos with mouse oviductal cells allows embryos to retain cleavage rates and viability comparable to in vivo development.
Detection and treatment of antispermatozoal antibodies in men
Authors: Hendry WF
Published: October 2005

Autoimmunity to spermatozoa results in the production of antisperm antibodies that usually reduce the fertility of human males. Many laboratory tests have been devised to detect antisperm antibodies, but the results of such tests do not always correlate well with each other, particularly when the tests are conducted with patients' own spermatozoa rather than donor sperm. Experience over the past 12 years at Chelsea Hospital for Women and St Bartholomew's Hospital in London has led to at Chelsea Hospital for Women and St Bartholomew's Hospital in London has led to the development of an effective method for testing and treating subfertile males. This involves using the mixed antiglobulin reaction test and the post-coital test as initial screening tests, followed by serum and seminal plasma agglutination tests (both gelatin and tray) and the sperm-cervical mucus contact tests. Suitable patients are then put on one of three steroid regimens--long-term low-dose prednisolone, intermittent high-dose methylprednisolone, or intermediate graduated-dose prednisolone. Such treatment is useful not only in cases of spontaneous autoimmunity, but also in cases involving genital infection, testicular obstruction, and in vitro fertilization or gamete intrafallopian transfer.
LIF: a molecule with divergent actions on myeloid leukaemic cells and embryonic stem cells
Authors: Gough NM , Williams RL , Hilton DJ , Pease S , Willson TA , Stahl J , Gearing DP , Nicola NA , Metcalf D
Published: October 2005

We have previously characterized, purified and cloned a novel murine and human regulator [leukaemia inhibitory factor, LIF] which induces the differentiation of certain murine and human myeloid leukaemic cells. Recently we have shown that there are specific LIF receptors on murine embryonic stem [ES] and embryonal carcinoma [EC] cells and that purified recombinant LIF can substitute for feeder cells and crude sources of differentiation inhibiting activity [DIA] [such as BRL-cell-conditioned medium] in the maintenance of ES cells in a pluripotential state in vitro. Furthermore, ES cells maintained in culture in recombinant LIF for a prolonged period can give rise to germline chimaeric mice. Thus, based on a number of biochemical and biological similarities, it is likely that LIF and DIA are the same molecule. The identification of LIF as a molecule, necessary and sufficient for the maintenance of ES cells in culture, should have a profound impact on the use of these cells for genetic manipulations.
Oxidative metabolic activity of boar spermatozoa: a system for assessing anti-glycolytic activity of potential inhibitors in vitro
Authors: Jones AR , Chantrill LA
Published: October 2005

The oxidative metabolic capability of mature boar spermatozoa has been determined in vitro. The high rate of oxidation of fructose, glucose, glycerol, glycerol-3-phosphate and lactate to CO2 and the optimization of incubation conditions indicates that these cells could constitute a model system for investigating the anti-glycolytic activity of potential male anti-fertility agents. The effects of several chemical agents on the oxidative metabolism of boar spermatozoa are reported.
Cellular composition of utero-ovarian lymph during the exogenous gonadotrophin-stimulated oestrous cycle in sheep
Authors: Alders RG , Press CM
Published: October 2005

Utero-ovarian peripheral lymph was collected for extended periods from sheep that had received exogenous gonadotrophins. High lymph flow rates and progesterone outputs, over 13 mL h-1 and 65 nmol h-1 respectively, were observed during the subsequent oestrous cycles. A positive correlation was found between the maximum lymph flow rate and the number of corpora lutea in the draining ovary. At periods approximating the beginning and end of the luteal phase of the oestrous cycle there were increases in the output of red blood cells and, towards the end of the luteal phase, eosinophils constituted over 10% of the white blood cells in the lymph. Lymph provides a dynamic record of the changing internal environment of the ovary and as such may yield useful information on intraovarian control mechanisms in sheep.
Artificial insemination of Cashmere goats: effects on fertility and fecundity of intravaginal treatment, method and time of insemination, semen freezing process, number of motile spermatozoa and age of females
Authors: Ritar AJ , Ball PD , O'May PJ
Published: October 2005

The experiments, using a total of 1833 Cashmere does, were conducted to examine the effects on fertility and fecundity of intravaginal treatment for control of ovulation, time of insemination by cervical and laparoscopic methods, semen processing in pellets and straws, and number of frozen-thawed motile spermatozoa. Adult does (greater than or equal to 2.5 years) that had previously kidded were inseminated into the cervix, and maiden (kid: 6-8 months; hogget: 18 months) and adult does were inseminated laparoscopically. The rates of pregnancy determined by ultrasonic scanning (75-80 days after insemination) for cervical (Experiment 1) and laparoscopic (Experiments 2 and 3) insemination were 39.1%, 63.6% and 52.1%. The number of motile spermatozoa did not affect fertility after cervical (80, 120 and 160 x 10(6) or laparoscopic (Experiment 2: 15, 30 and 60 x 10(6); Experiment 3:5, 10 and 20 x 10(6) insemination. The method of insemination or number of motile spermatozoa did not affect fecundity. With cervical insemination, fertility and fecundity improved with increasing depth of insemination into the reproductive tract. Intravaginal sponges containing fluorogestone acetate and controlled internal drug release (CIDR) devices containing progesterone were equally effective for control of ovulation when combined with an injection of pregnant mare's serum gonadotrophin (PMSG; 200 i.u.) before insemination. Fertility was higher when does were inseminated before than after ovulation. After laparoscopic insemination, results were similar for semen frozen as pellets and in straws, and for 3-, 6- and 24-fold pre-freezing dilution of semen. For kid, hogget and adult does in Experiment 3, pregnancy rates were 34.0%, 55.4% and 63.9% and rates of fecundity were 1.17, 1.22 and 1.27 fetuses/pregnant doe.
Effects of indomethacin, during pregnancy in the rat, on responses to noradrenaline and angiotensin II in vivo, and responses to phenylephrine in vitro
Authors: Jansakul C , King RG , Boura AL
Published: October 2005

Pressor responses to both angiotensin II (Ang II) and noradrenaline (NA) were reduced in 20-day-pregnant rats compared with those in non-pregnant animals, regardless of whether the results were expressed in terms of the dose per kilogram of body weight or per millilitre of estimated plasma volume. Inhibition of prostaglandin production with indomethacin (10 mg kg-1, i.v.) was not accompanied by any significant effect on responses to Ang II in either non-pregnant or 20-day-pregnant animals. However, it attenuated the effects of NA in 20-day-pregnant rats. Indomethacin (10(-5) or 3 x 10(-5) M) did not potentiate in vitro vasoconstrictor responses to phenylephrine of endothelium-intact or -denuded thoracic aortic rings from non-pregnant or 20-day-pregnant rats. These results suggest that subsensitivity to Ang II or NA during pregnancy in the rat is not due to dilution of the dose of these autacoids resulting from increased plasma volume, nor to an increased output of vasodilator prostaglandins.
Prostaglandin alone does not cause luteolysis in the non-pregnant tammar wallaby, Macropus eugenii
Authors: Hinds LA
Published: October 2005

At parturition in the tammar wallaby, Macropus eugenii, the process of luteolysis involves both prostaglandin and prolactin. Prolactin alone is luteolytic, but it has been unclear whether prostaglandin F2 alpha (PGF2 alpha) is also directly luteolytic. To examine this, three groups non-pregnant animals were studied on Day 26 after removal of pouch young (the day equivalent to parturition). Group 1 (controls) received saline injections on Days 25 and 26, Group 2 received saline on Day 25 and PGF2 alpha on Day 26, and Group 3 was pre-treated with bromocriptine (Parlodel LA, Sandoz) on Day 25 and received PGF2 alpha on Day 26. For 12 h after treatment on Day 26, plasma progesterone and prolactin concentrations were determined and behaviour was recorded. Plasma progesterone concentrations remained elevated and plasma prolactin was basal throughout the sampling period in the control animals (Group 1). After treatment with PGF2 alpha (Group 2), plasma prolactin was elevated within 15 min and plasma progesterone decreased significantly (P less than 0.001) from 600 pg mL-1 (1.91 nmol L-1) to less than 200 pg mL-1 (0.64 nmol L-1) by 8 h. However, luteolysis did not occur in females pre-treated with bromocriptine on Day 25 and injected with PGF2 alpha on Day 26 (Group 3), and prolactin concentrations remained basal. All females treated with PGF2 alpha showed parturient behavior. The results clearly show that PGF2 alpha is not directly luteolytic on Day 26 of the non-pregnant cycle, but they confirm that PGF2 alpha induces the release of prolactin, which is directly luteolytic.
Exogenous progesterone and embryo survival in Booroola-cross ewes
Authors: Kleemann DO , Walker SK , Grimson RJ , Smith DH , Grosser TI , Seamark RF
Published: October 2005

To investigate if exogenous progesterone improves embryo survival, 209 multiparous Booroola Merino x South Australian Merino ewes, heterozygous for the F gene (F+) were allocated to seven treatment groups and inseminated at a synchronized oestrus. Six groups received progesterone from controlled internal drug release G dispensers on the following days after ovulation: 4-7, 4-11, 4-14, 7-11, 7-14 and 11-14. Concentration of peripheral progesterone increased (P less than 0.05) in most supplemented groups, but there were no significant differences in pregnancy rates between treatments. However, the number of fetuses per pregnancy was increased for progesterone treatments starting on Day 4 (Days 4-7, 4-11 and 4-14 combined v. control; P less than 0.05) and for all supplemented treatments compared with the control (P less than 0.05).
Artefactual loss of human ovarian surface epithelium: potential clinical significance
Authors: Gillett WR
Published: October 2005

To investigate whether the human ovarian surface has an intact epithelial layer, 69 ovarian biopsies from 39 women were taken. When the surface was touched or wiped, there was a widespread loss of cells that were otherwise retained in surface depressions or crypts. By avoiding contact with the surface, the layer was retained. A temporary disruption to the surface following ovulation was followed by complete healing and re-epithelialization. These observations suggest that previous studies describing the loss of surface epithelium may have artifactually generated this loss, possibly by handling the surface during surgical retrieval. The possible clinical significance of these observations is that inadvertent ovarian handling during any ovarian surgery may be implicated in the pathogenesis of adhesion formation, simply by removing the surface that is important in tissue repair.
Effect of lupin (Lupinus angustifolius) supplementation on ovarian and pituitary activity in ewes
Authors: Pearse BH , McMeniman NP , Dowsett KF
Published: October 2005

In each of three experiments, thirty seasonally anoestrous Border Leicester ewes were fed on a maintenance ration of oaten chaff. Fifteen of them were given a supplement of 500 g lupin grain per head per day. The ewes were treated with 10 mg follicle stimulating hormone (Expt 1), 600 I.U. pregnant mare serum gonadotrophin (Expt 2) and either 150 or 300 micrograms gonadotrophin releasing hormone (Expt 3) to determine whether the ovaries and/or the anterior pituitary were capable of responding to the nutrient status of the animals and influencing ovulation rate. In each experiment, the number and size of corpora lutea and follicles in the lupin-supplemented and -unsupplemented groups were similar. It was concluded that the mechanism by which lupins increase the ovulation rate is probably neural and not a result of direct effect on either the pituitary or the ovaries.
Regulation of prostaglandin synthesis in the human amnion
Authors: Olson DM , Smieja Z , Zakar T , MacLeod EA , Walton J , Milne K
Published: October 2005

An increase in prostaglandin synthesis by intrauterine tissues may be responsible for labour initiation and/or maintenance in humans. In all studies to date, the amnion is the intrauterine tissue whose prostaglandin output consistently increases with the onset of labour. This may be due, in part, to acute activation of the phospholipases A2 and C and to an increase in the specific activity of prostaglandin H synthase (PGHS). A number of factors exist in amniotic fluid, the fetal membranes, the decidua and the placenta that can increase PGHS specific activity. Some of these factors may increase PGHS enzyme activity by gene expression and protein synthesis. Preliminary evidence is presented that suggests the hypothesis that PGHS specific activity increases before the onset of labour rather than as a consequence of labour initiation, and that idiopathic preterm labour may frequently be associated with increased PGHS activity. Hence, activation of PGHS gene expression and/or protein synthesis may be causal for term and preterm labour.
Role of the fetal parathyroid glands and parathyroid hormone-related protein in the regulation of placental transport of calcium, magnesium and inorganic phosphate
Authors: MacIsaac RJ , Heath JA , Rodda CP , Moseley JM , Care AD , Martin TJ , Caple IW
Published: October 2005

The plasma Ca concentration of the fetus is maintained higher than maternal levels by active placental transport. Ca, Mg and PO4 accumulation by the fetus is mainly associated with skeletal growth. The fetal parathyroid glands are essential for maintenance of elevated plasma Ca, which is necessary for the stimulation of fetal osteoblasts and mineralization of cartilage and osteoid. Fetal thyroparathyroidectomy (TxPTx) results in a decreased activity of the placental Ca pump. The presence of a parathyroid hormone-related protein (PTHrP) has been demonstrated in fetal parathyroid glands and placental tissue. Extracts of fetal parathyroid glands and purified PTHrP, as well as recombinant PTHrP (1-84, 1-108 and 1-141), stimulate Ca and Mg but not PO4 transport across the placenta of TxPTx-ized fetuses perfused with autologous blood in the absence of the fetus. Parathyroid hormone (PTH) and the N-terminal region of PTHrP do not stimulate placental Ca and Mg transport. It is concluded that a mid-molecule region of this novel hormone may be required to stimulate placental Ca transfer and contribute to the regulation of fetal Ca homeostasis.
Acetylcholine output and materno-fetal alpha-aminoisobutyric acid transfer in the perfused human placental lobule
Authors: Krishna BR , King RG , Brennecke SP
Published: October 2005

Dually perfused human placental lobules were employed to study the effects of vesamicol (an inhibitor of acetylcholine (ACh) storage) and physostigmine (an inhibitor of cholinesterase breakdown of ACh) on ACh output from fetal vessels and on materno-fetal transfer of the nonmetabolizable amino acid alpha-aminoisobutyric acid (AIB). Bilateral perfusion with vesamicol (100 mumol L-1) or omission of physostigmine (2 x 7 mumol L-1) from the perfusate significantly reduced the output of ACh. However, neither drug had any significant effect on AIB transfer. Thus, the results of this study do not provide evidence for a close relationship between the placental cholinergic system and materno-fetal AIB transfer.
Administration of prostaglandin inhibitors to the mother; the potential risk to the fetus and neonate with duct-dependent circulation
Authors: Menahem S
Published: October 2005

Two infants were delivered by urgent Caesarean section at 34 weeks because of fetal distress. One rapidly developed severe cardiac failure and the other marked cyanosis. Their mothers had been prescribed indomethacin and mefenamic acid (Ponstan) to treat premature onset of labour and chronic polyhydramnios, respectively. Both infants had duct-dependent circulations, their cross-sectional echocardiography showing only a small (1-2 mm diameter) patent ductus arteriosus. The early onset and severity of their symptoms suggested that the maternal intake of prostaglandin inhibitors may have deleteriously led to early closure of their ducts, essential in duct-dependent circulations. Although such occurrences are rare, fetal cross-sectional echocardiography should be performed prior to administration of prostaglandin inhibitors during pregnancy.
Endothelin: release by and potent constrictor effect on the fetal vessels of human perfused placental lobules
Authors: Gude NM , King RG , Brennecke SP
Published: October 2005

Human placental lobules were bilaterally perfused with a modified Krebs solution at constant flow rates of 5 mL min-1, and fetal inflow perfusion pressure was recorded. The effect of infusions of endothelin-1 and endothelin-3 (ET-1 and ET-3) on the perfusion pressure was assessed and compared with that for the thromboxane A2-mimetic U46619 and prostaglandin F2 alpha (PGF2 alpha). All substances caused significant increases in pressure, ET-1 being the most potent, followed in order by U46619, ET-3 and PGF2 alpha. In addition, ET-like immunoreactivity was identified in the fetal effluent of placental lobules during 4 h of basal perfusion. The mean ET-1 equivalent immunoreactivity at 1 h of perfusion was 0.6 +/- 0.2 fmol min-1 g-1 of wet lobule weight for 10 placentae. These data suggest that human fetal placental endothelial cells are capable of synthesizing ETs and that ETs are potent constrictors of the fetal placental vessels. Thus, endothelins may play a role in the control of fetal vascular tone in the human placenta in normal and/or pathological conditions.
Detection of anti-ovarian antibodies by indirect immunofluorescence in patients with premature ovarian failure
Authors: Kirsop R , Brock CR , Robinson BG , Baber RJ , Wells JV , Saunders DM
Published: October 2005

The sera of 30 patients with premature ovarian failure (POF) and a control group of 19 menopausal women were screened for anti-ovarian and other tissue antibodies. Anti-ovarian antibodies were detected by indirect immunofluorescence using monkey ovary substrates from two different commercial sources. Serum anti-ovarian antibodies were detected in only one of the patients with POF. This test does not appear to be reliable for the detection of serum anti-ovarian antibodies, and the clinical usefulness of screening patients with POF for anti-ovarian antibodies is questionable.
Increased production of sheep embryos following superovulation of Merino ewes with a combination of pregnant mare serum gonadotrophin and follicle stimulating hormone
Authors: Ryan JP , Hunton JR , Maxwell WM
Published: October 2005

In a factorially designed experiment (N = 321), 0, 800 or 1600 I.U. pregnant mare serum gonadotrophin (PMSG) were administered in combination with 0, 12 or 18 mg follicle stimulating hormone (FSH-P) to superovulate Merino ewes in autumn and spring. A moderate dose of PMSG (800 I.U.) in conjunction with 12 or 18 mg FSH-P increased the ovulation rate above that observed when FSH-P was used alone. This was accomplished by (i) increasing the proportion of ewes that exhibited a superovulatory response (greater than 3 corpora lutea (CL) or persistent large follicles (LF): 69/70 (99%) v. 55/74 (74%), P less than 0.001), and (ii) in those ewes that exhibited a superovulatory response, by an additive effect of exogenous gonadotrophin (14.8 +/- 0.9 CL (69) v. 11.3 +/- 0.9 CL (55), P less than 0.01) without increasing the incidence of LF. The use of 1600 I.U. PMSG in conjunction with 12 or 18 mg FSH-P was characterized by an increase in the number of LF and, in comparison with 800 I.U. PMSG, a reduction in ovulation rate. Season had no effect on the numbers of CL, but total ovarian response (CL + LF) was higher in autumn than in spring (P less than 0.01), because of a greater incidence of LF (P less than 0.001). The proportion of ewes with regressed CL was higher in autumn than in spring (53/143 (37%) v. 32/156 (21%), P less than 0.01), and increased with increased dose of gonadotrophin. Furthermore, a nutritional component to the incidence of ewes with regressed CL was suggested by the observation that the mean concentration of plasma glucose was higher for ewes with normal CL than for ewes with regressed CL (P less than 0.05). Rates of ova or embryo recovery, fertilization and embryo development generally declined with an increase in the incidence of LF as a result of increases in the dose of gonadotrophin and season of administration.
Superovulation of Merino ewes with an ovine pituitary follicle stimulating hormone extract
Authors: Jabbour HN , Evans G
Published: October 2005

In order to investigate the effectiveness of ovine FSH as a superovulatory gonadotrophin in sheep, three batches (oFSH-1, oFSH-2 and oFSH-3) of crude follicle stimulating hormone (FSH) extracts were prepared from ovine pituitaries by protein fractionation. The extracts were characterized in radioimmunoassays (RIA), radioreceptor assays (RRA) and bioassays. A FSH:LH (luteinizing hormone) ratio of 1:0.71 and 1:0.18 was calculated from oFSH-1 in RIA and RRA respectively. oFSH-1 was more potent than NIH-oFSH-S12 in RRA, with a potency ratio of 1:0.65 calculated at 50% binding. In mouse bioassay, oFSH-2 was effective in inducing folliculogenesis. The potency of oFSH-3 as an ovarian stimulatory hormone was tested in a field trial on sheep. Thirty-one mature Merino ewes were treated in the breeding season with intravaginal progestagen pessaries and 6, 12 or 24 mg doses of oFSH-3 were injected twice daily for 3 days (n = 10 or 11). Each ewe was inseminated in the uterus with fresh semen 24 h after pessary withdrawal. Ova or embryos were recovered by mid-ventral laparotomy 6 or 7 days after pessary withdrawal. The dose of oFSH-3 had a significant effect on the ovulatory response (P less than 0.01); the mean ovulation rates were 1.5 +/- 0.2, 12.6 +/- 2.8 and 13.1 +/- 2.9 following injection with 6, 12 or 24 mg of the gonadotrophin respectively. The dose of the gonadotrophin injected had no effect on the mean percentages of ova recovered or fertilized. The overall ova recovery and fertilization rates (%) were 67.8 +/- 6.4 and 92.2 +/- 5.1 respectively. (ABSTRACT TRUNCATED AT 250 WORDS)
Growth in vitro and acquisition of meiotic competence after the cryopreservation of isolated mouse primary ovarian follicles
Authors: Carroll J , Whittingham DG , Wood MJ
Published: October 2005

The growth and acquisition of meiotic competence of oocytes from fresh and frozen-thawed primary follicles collected from 10-day-old mice was compared during culture in collagen gels for 12 days. The oocytes contained in primary follicles have a mean diameter of about 48 microns and do not resume meiosis without further growth and development. During the 12-day culture period the mean diameter of the oocytes increased to over 60 microns. The oocytes were capable of resuming meiosis when isolated from the gel and cultured in the absence of follicular cells in a manner similar to that observed in vivo. Freezing and thawing did not affect oocyte growth or the ability to resume meiosis; this demonstrates the possibility of storing large numbers of female gametes for subsequent development.
Is the antiprogestin RU486 luteolytic in rats?
Authors: Martin L , Crane LH
Published: October 2005

Subcutaneous injections of RU486 on Day 1, Day 4 or Days 3 and 4 of pregnancy in rats induced abortion of the embryo and transient vaginal cornification. Nevertheless, most corpora lutea appeared to be functional at autopsy on Day 12. The same treatments in pseudopregnant rats also produced transient vaginal cornification, but did not terminate pseudopregnancy. This suggests that transient antagonism of progesterone by RU486 does not terminate function of the corpus luteum in rats and that positive feedback by progesterone is not essential for continuing luteal function in rats.
Time of ovulation in merino ewes superovulated with PMSG and FSH-P
Authors: Ryan JP , Hunton JR , Maxwell WM
Published: October 2005

An experiment examined the effects of treatment with gonadotrophin releasing hormone (100 micrograms GnRH injected 24 h after progestagen sponge removal), season of treatment (autumn v. spring), the effect of supplementary feeding with lupin grain (in autumn only, from 12 days before until 8 days after sponge removal) on the time of ovulation in 182 mature Merino ewes superovulated with a combination of 400 I.U. pregnant mare serum gonadotrophin (PMSG) and 12 mg follicle stimulating hormone (FSH-P). Time of ovulation was influenced by both season and the administration of GnRH. Two peaks of ovulation were observed in spring, the first between 24 and 30 h after sponge removal, and the second commencing 42 h after sponge removal. In autumn, there was one peak of ovulation between 42 and 54 h after sponge removal. Treatment with GnRH advanced the time of ovulation in autumn (P less than 0.05), but had no apparent effect in spring. In contrast to the effect of GnRH, time of ovulation for ewes treated in autumn was delayed (P less than 0.001) by supplementary feeding with lupins.
Granulocyte-macrophage colony stimulating factor (GM-CSF): one of a family of epithelial cell-derived cytokines in the preimplantation uterus
Authors: Robertson SA , Seamark RF
Published: October 2005

Granulocyte-macrophage colony stimulating factor (GM-CSF) is one of a number of lympho-haemapoietic cytokines, including CSF-1, interleukin-6 (IL-6) and leukaemia inhibitory factor (LIF) now known to be synthesized by epithelial cells in the murine uterus. GM-CSF synthesis is regulated primarily by the ovarian steroid hormone oestrogen, but is also subject to modulation by factors including a seminal component of seminal vesicle origin which stimulates a 20-fold increase in luminal fluid content at mating, and bacterial lipopolysaccharide (LPS) and the T-lymphocyte and natural killer (NK) cell product interferon-gamma (IFN gamma). In the non-pregnant mouse GM-CSF synthesis peaks at oestrus. Synthesis is maintained at comparable or moderately higher levels during the preimplantation period of pregnancy and in the non-decidualized endometrium during mid gestation. An embryotrophic activity is suggested by studies in vitro that indicate that GM-CSF stimulates attachment and outgrowth of blastocysts. It is postulated that GM-CSF is of major importance to the physiology of pregnancy through its role as a component of a local cytokine circuit acting to recruit and regulate function of endometrial leukocytes, and by its action as interlocutor and important effector arm in embryo-maternal interactions during gestation.
Oocyte Donation for Genetic Indications
Authors: Van Steireghem AC , Pados G , Devroey P , Bonduelle M , Van Assche E , Liebaers I
Published: October 2005

Oocyte donation is now a 'routine' treatment for infertility. Oocyte donation is mainly carried out in
women with primary ovarian failure or premature menopause or in women in whom different regimens
of ovarian stimulation prevent the development of ovarian follicles. In our Centres, oocyte donation
is also offered to women or couples who prefer not to use their own gametes because of high recurrent
risk of chromosomal or monogenic diseases. The resulting pregnancies in these women as well as in a
series of women with gonadal dysgenesis due to X-chromosome aneuploidies are reported.
Psychosocial Followup of Families
from a Donor Oocyte Programme:
an Exploratory Study
Authors: Munro J , Leeton J , Horsfall T
Published: October 2005

A questionnaire completed by 29 couples provided information on their history of infertility, their
involvement in the donor oocyte programme and their subsequent family relationships.
Practical Aspects of Oocyte Donation
Authors: Critchley HOD , Healy DL , King CM , Leeton JF
Published: October 2005

The concluding session of the symposium on Oocyte Donation held in Melbourne in
November 1991 focused upon the practical aspects of an oocyte donation programme.
A background is here provided to the many exogenous sex steroid replacement regimens
and clinical management protocols employed by centres throughout Europe, the United
States and Australia. The participants were asked to provide information about their own
centres' protocols (Tables 1, 2 and 3). In addition, a panel considered a hypothetical request
for oocyte donation. A summarized case history and the ensuing discussion concerning
management is presented.
Fertilizing capacity of bovine spermatozoa selected after swim-up in hyaluronic acid-containing medium
Authors: Shamsuddin M , Rodriguez-Martinez H , Larsson B
Published: October 2005

Hyaluronic acid (HA) was used to select spermatozoa from frozen-thawed semen from five bulls; two were highly fertile and three had low fertility related to low post-thaw motility of the spermatozoa. Spermatozoa were collected after 1 h of self-migration in one of two media: a modified Tyrode's lactate solution (TALP) or a medium consisting of equal volumes of TALP and phosphate-buffered saline to which HA was added to obtain a final concentration of 1 mg mL-1 (HA medium). The selected spermatozoa were used to inseminate oocytes matured in vitro at a concentration of either 1.0 x 10(6) or 0.5 x 10(6) mL-1, constituting a 5 x 2 x 2 factorial experiment. After 19-22 h of sperm-oocyte co-incubation, fertilization of oocytes was assessed. The two concentrations of spermatozoa differed significantly in the percentage of oocytes penetrated (P = 0.001) and the percentage of oocytes with two pronuclei (P = 0.002). When 1.0 x 10(6) mL-1 spermatozoa were used, spermatozoa collected after swim-up in the HA medium fertilized more oocytes (P = 0.01) than did those collected after swim-up in TALP. Variation between bulls was also significant (P = 0.002). The beneficial effect of the HA medium was more evident in the group of low-fertility bulls (P < or = 0.03), where neither the variation between bulls (P > or = 0.06) nor the interaction between the methods of sperm selection and bulls (P > or = 0.10) was significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Effect of oxygen concentration on the incorporation of glucose by the sheep conceptus between days 13 and 19 of pregnancy
Authors: Du ZF , Wales RG
Published: October 2005

Embryos and extraembryonic membranes recovered from the sheep conceptus on Days 13, 15, 17 and 19 of pregnancy were incubated in medium containing glucose as sole energy substrate. In all components of the conceptus 60-70% of substrate carbon incorporated was recovered in the non-glycogen acid-soluble fraction, 25-30% in non-glycogen macromolecules and 4-8% in the glycogen pools. At all stages of development examined, embryonic tissue accumulated more glucose carbon into all fractions than did yolk sac which in turn was more active than trophoblast. After its appearance, the allantois was at least as active in glucose incorporation as embryonic tissue. Over the period of development examined, incorporation into all tissues of the conceptus fell progressively as pregnancy advanced and, by Day 19, total incorporation was about 60% of the initial value for each component. Reduction in oxygen concentration generally depressed incorporation into all intracellular carbon pools. The most consistent and significant effects were recorded for the two non-glycogen pools where incorporation fell, on average, by 30-40% when O2 concentration was reduced to 1%. Most of the response observed was due to a drop in O2 concentration from 20 to 5% with smaller additional effects when the O2 was further reduced to 1%. Incorporation into all pools isolated tended to follow a similar pattern and incorporation into the three macromolecular components, expressed as a percentage of total incorporation, remained unchanged as O2 concentration was reduced.
The potential impact of sperm encapsulation technology on the importance of timing of artificial insemination: a perspective in the light of published work
Authors: Watson PF
Published: October 2005

To facilitate artificial insemination with encapsulated spermatozoa independently of oestrus, ways must be found to extend the life of spermatozoa at body temperature, and to devise encapsulation procedures which will allow progressive release of viable spermatozoa over several days. In the past, the most common approach to the preservation of semen has been the principle of reduced temperature. However, the research literature presents several promising clues to the resolution of these problems; these are reviewed, and new directions are identified and explored. The potential impact of a successful encapsulation technology is recognized as the driving force for implementing the novel research required.
A free radical theory of male infertility
Authors: Aitken RJ
Published: October 2005

There is a growing body of evidence to indicate that a significant factor in the aetiology of male infertility involves a loss of sperm function as a consequence of oxidative stress. This stress originates from the excessive generation of reactive oxygen species by the spermatozoa and results in the peroxidation of unsaturated fatty acids in the sperm plasma membrane. It is possible that reactive oxygen species originating from infiltrating leucocytes could also stress the spermatozoa although the protective properties of seminal plasma would render this unlikely in vivo. Whatever the source of the reactive oxygen species, the lipid peroxides thereby generated exhibit powerful negative correlations with the movement characteristics of the spermatozoa and their capacity for sperm-oocyte fusion. These findings should have important implications for the development of rational techniques for the diagnosis and treatment of male infertility.
Hormonal control of testicular descent and the cause of cryptorchidism
Authors: Hutson JM , Baker M , Terada M , Zhou B , Paxton G
Published: October 2005

This paper briefly reviews the literature on testicular descent and presents new observations from the authors' laboratory which suggest new ways of looking at old problems. There is now good evidence that testicular descent occurs in two morphologically and hormonally distinct phases. Relative 'transabdominal migration' of the testis compared with the ovary occurs at 10-15 weeks of gestation in the human and 'inguinoscrotal' migration occurs at 26-35 weeks of gestation. We have proposed previously that the first phase is controlled by Mullerian inhibiting substance although this remains controversial. The second phase is androgen dependent and is possibly mediated indirectly through the release from the genitofemoral nerve (GFN) of the neuropeptide calcitonin gene-related peptide (CGRP). Recently we have used three different rodent models of undescended testis to determine the involvement of the GNF and/or CGRP. The testicular feminization mouse with complete androgen resistance and the rat exposed prenatally to the antiandrogen flutamide have a deficiency of CGRP in the GFN. In contrast, the mutant trans-scrotal rat which has normal androgen levels has an excess of CGRP in the GFN. All cryptorchidism models, despite their different primary cause, have in common an abnormality of the GNF and/or CGRP which is consistent with the hypothesis that normal testicular descent in the rodent may be mediated by the GFN.