bluuebunny/crossref_metadata_2025 huggingface dataset:
Energy transfer between Co2+ and Fe2+ ions in diffusion-doped ZnSe
Authors: Luo Ming , Giles N. C. , Roy Utpal N. , Cui Yunlong , Burger Arnold
Published: October 2005

Absorption, photoluminescence (PL), and time-resolved PL measurements were applied to samples of polycrystalline ZnSe which were diffusion doped with iron or with cobalt or codoped with both iron and cobalt. Characteristic emission and absorption features due to Co2+ and Fe2+ were observed in the visible and infrared regions. In the spectral region near 3μm, a Co2+ emission overlaps completely with an Fe2+ absorption and energy transfer occurs. Using PL lifetime data, a decrease in the Co2+ lifetime of ∼300μs to less than 100μs was observed. This decrease in lifetime indicates that the nature of the energy-transfer process is nonradiative. The energy-transfer rate decreases with temperature, as expected for the nonradiative electric dipole-dipole interaction. The temperature dependences of both Co2+ and Fe2+ emissions are described.
Femtosecond nonlinear coherence spectroscopy of carrier dynamics in porous silicon
Authors: Van Dao Lap , Hannaford Peter
Published: October 2005

Multidimensional nonlinear coherence spectroscopy based on spectrally resolved femtosecond two-color three-pulse photon echo measurements are used to investigate carrier dynamics and energy structures in porous silicon samples, an indirect band-gap material. Short time scales for electron localization (∼500fs) and electron hopping (∼3ps) are observed which are dependent on the porosity of the samples. A spin-orbit splitting for the conduction band of 4–5meV is deduced. The observed energy splittings of 18 and 22meV for the 48% porosity sample and 21 and 28meV for the 70% porosity sample are assigned to spin-orbit splitting for the valence band.
Formation rates of iron-acceptor pairs in crystalline silicon
Authors: Macdonald Daniel , Roth Thomas , Deenapanray Prakash N. K. , Bothe Karsten , Pohl Peter , Schmidt Jan
Published: October 2005

The characteristic association time constant describing the formation of iron-acceptor pairs in crystalline silicon has been measured for samples of various p-type dopant concentrations and species (B, Ga, and In) near room temperature. The results show that the dopant species has no impact on the pairing kinetics, suggesting that the pairing process is entirely limited by iron diffusion. This conclusion was corroborated by measurement of the activation energy of pair formation, which coincides with the migration enthalpy of interstitial iron in silicon. The results also indicate that the pair-formation process occurs approximately twice as fast as predicted by a commonly used expression.
Equilibrium magnetic moment configurations in magnetic nanoparticle films: Effects of anisotropy, dipolar interaction, and Zeeman energy
Authors: Xu C. , Ma Y. Q. , Hui P. M.
Published: October 2005

The equilibrium configurations of films consisting of magnetic small particles in which the anisotropy energy tends to align the magnetic moments perpendicular to the film are studied by Monte Carlo simulations. The effects of anisotropy energy, dipolar interaction, and Zeeman energy due to an external applied magnetic field, which can either be perpendicular or parallel to the film, are considered. As the relative strength of the relevant interaction energies changes, the system exhibits a variety of different magnetic moment configurations. Due to the competition between the dipolar interaction energy and the anisotropy energy, it is found that an approximately antiferromagnetic alignment with moments oriented perpendicular to the film results when the anisotropy energy dominates; while an in-plane antiferromagnetic alignment results when the dipolar interaction energy dominates. Results obtained by a zero-temperature analysis based on energy minimization are found to be in qualitative agreement with results obtained by numerical simulations.
Carbon nanotube probes for single-cell experimentation and assays
Authors: Kouklin N. A. , Kim W. E. , Lazareck A. D. , Xu J. M.
Published: October 2005

Integrating nanotechnology with experimental biology is paramount to advancing fundamental biological science and technology, and, therefore, of high current interest and importance. In this article, we report on a new possibility of utilizing carbon nanotube probes assembled by a modified dielectrophoretic based technique for single-cell experimentation and delivery. The modified approach permits highly reproducible construction of water-stable, highly-aligned, and electrically-conductive probes several hundred microns in length, which hold a great promise for enhancing previously developed molecular-scale intracellular experimental techniques. The results of this work, in particular, indicate that the minimally invasive nanotube probes could be advantageous for studies involving permeabilization and subsequent desorption of molecules into a cell’s interior, thereby obviating permeabilization and diffusion across membranes.
Development of a 27.12MHz radio frequency driven ion source with 3mTorr operation pressure for neutron generators
Authors: Jiang Ximan , Chen Ye , Ji Lili , Ji Qing , Leung Ka-Ngo
Published: October 2005

An inductively coupled rf plasma ion source has been developed for neutron generators. The ion source configuration has been optimized for low pressure operation. Both 13.56 and 27.12MHz rf powers have been used to generate hydrogen plasma. Experimental results show that 27.12MHz operation is more efficient than 13.56MHz in a low pressure region. The ion source can also be operated in pulsed mode. Current density higher than 30mA∕cm2 can be extracted from a 2-mm-diam aperture at 2kW rf input power and 3mTorr operation pressure.
Bulkier glass formability enhanced by minor alloying additions
Authors: Ma D. , Cao H. , Ding L. , Chang Y. A. , Hsieh K. C. , Pan Y.
Published: October 2005

In this study, we present a computational thermodynamic strategy to obtain a minor but optimum amount of additional element into a base alloy to improve its glass-forming ability, through thermodynamically calculating the maximum liquidus depressions caused by various alloying addition (or replacement) schemes. We demonstrate the successful use of Zr56.2Cu31.3Ni4.0Al8.5 as the base alloy with the addition of 4.9% Ti, by observing a significant increase in the glass-forming ability of more than 100% in terms of the diameter of the glass formed from the base alloy to the one with the addition of 4.9% Ti. The approach presented here can be considered as a universal method to synthesize novel and bulkier metallic glasses not only of scientific interest but also potential technological applications.
Germanium n+∕p junction formation by laser thermal process
Authors: Huang Jidong , Wu Nan , Zhang Qingchun , Zhu Chunxiang , Tay Andrew A. O. , Chen Guoxin , Hong Minghui
Published: October 2005

In this letter, an n+∕p junction on a germanium substrate, formed by phosphorous implantation and subsequent laser thermal annealing process, is demonstrated. The effects of laser energy fluence and irradiation pulse number on the redistribution of dopant atoms have been investigated. The secondary-ion-mass-spectrometry results indicate that steplike dopant profiles are formed with dopant atoms extending deeper upon increased laser energy fluence and successive pulse number. After being irradiated at a laser energy fluence of 0.16J∕cm2 with two successive pulses, the junction exhibits a sheet resistance of ∼50Ohm∕sq for n+ region, a comparable current-voltage characteristic, and much less phosphorus dopant diffusion in comparison with those formed by rapid thermal process annealing.
Adiabatic matching stage for coupling of light to extended Bloch modes of photonic crystals
Authors: Momeni B. , Adibi A.
Published: October 2005

In this letter, we present a matching stage for reflection reduction based on the principle of gradual change to efficiently couple light to propagating modes of photonic crystals (PCs). Basic physical considerations in designing these matching stages are investigated and a systematic yet simple design procedure is suggested. We show that matching stages obtained using this method are wideband in frequency, have a wide acceptance angle, and are robust against fabrication imperfections. Therefore, they are the preferred choice in general-purpose matching stages to be used along with dispersion-based PC devices.
Superconducting noise bolometer for terahertz radiation
Authors: Semenov A. D. , Richter H. , Hübers H.-W. , Il’in K. S. , Siegel M.
Published: October 2005

We present a superconducting noise bolometer that is a bolometric detector sensing radiation via radiation-induced changes of its own microwave noise. The detector represents a nanostrip made from a thin NbN superconducting film. It operates in the superconducting state and carries a supercurrent slightly less than the critical current. Radiation couples with the detector via an immersion lens and a planar antenna, which jointly define the useful spectral range from 1to5THz. At an ambient temperature of 4.2K, the optically measured noise-equivalent power amounts at ≈10−13WHz−1∕2 along with a time constant of approximately 150ps.
Scaling laws for dual radio-frequency capacitively coupled discharges
Authors: Chung T. H.
Published: October 2005

The characteristics of dual radio-frequency capacitively coupled discharges are studied based on a homogeneous analytic model. We are considering a planar plasma device that can be approximated using a one-dimensional model. A set of equations describing the dynamics of the system are presented and used to give the analytic scaling laws. Scaling laws relating the drive frequencies and the applied voltages of dual radio-frequency sources to operating functions such as plasma density and plasma potential are examined and compared with numerical simulations.
Volume of fluid and concentration of cations and energy substrates in the uteri of mice during early pseudopregnancy
Authors: Wales RG , Edirisinghe WR
Published: October 2005

Estimates of the volume of fluid and the concentration of cations in the uterus were made by flushing the uterine cavity of mice mated to vasectomized males and measuring the concentrations of sodium and potassium cations in the recovered fluid. On day 1 following mating, large volumes of fluid (greater than 90 microL) were found in the uterus but, from days 2 to 5, only 2-5 microL of fluid were present. The ratio of sodium to potassium fell from 4.5:1 on day 1 to 1.8:1 on days 2 to 5 of pseudopregnancy, indicating that uterine fluid in the mouse has a high K+ content ranging from 35 mEq L-1 on day 1 to 75 mEq L-1 on day 5. Glucose, lactate and pyruvate in uterine flushings were also assayed and their concentration in uterine fluid calculated using the volumes found above. The level of all substrates was low on day 1 after mating. From day 2 onwards approximately 1 mM glucose was present in the fluids. The concentration of lactate was more variable, and peaked at 4 mM on day 2 of pseudopregnancy. In general, the concentration of pyruvate was 10% of the lactate value.
Concentrations of FSH are elevated in new-born ewe lambs carrying the Booroola F gene but not in lambs from a prolific Romney strain
Authors: Montgomery GW , Scott IC , Littlejohn RP , Davis GH , Peterson AJ
Published: October 2005

Concentrations of FSH were measured in new-born lambs in Booroola Merino x Romney and Booroola Merino flocks where the Booroola F gene was segregating, and in progeny from sires of a prolific strain of Romney sheep. FSH concentrations increased with age and liveweight in Booroola Merino x Romney ewe lambs to reach peak concentrations at 4-6 weeks of age. Significantly higher mean concentrations were recorded in ewe lambs homozygous for the Booroola gene (FF) compared with non-carrier (+ +) ewe lambs. Concentrations in heterozygous (F+) ewe lambs were intermediate. Maximum differences between the genotypes were recorded at 6 weeks of age. Significantly higher FSH concentrations were also recorded in F-gene-carrier female lambs when compared to non-carriers in two other flocks. FSH concentrations remained low in ram lambs up to 12 weeks of age, and there were no differences between Booroola genotypes. The progeny of one ram from the prolific Romney family had high ovulation rates at 18 months of age. The progeny of other related rams showed no increase in ovulation rates at 18 months of age. Concentrations of FSH in the high-ovulation-rate progeny at 3 and 5 weeks of age did not differ from those in the low-ovulation-rate progeny, but were lower than those in the progeny of an FF Booroola Merino x Romney ram. These results support the hypothesis that neonatal concentrations of FSH are higher in lambs carrying the Booroola F gene, but not in all prolific strains since high FSH concentrations were not recorded in daughters from a prolific Romney flock.(ABSTRACT TRUNCATED AT 250 WORDS)
Transgenesis: the challenge for the reproductive biologist
Authors: Seamark RF
Published: October 2005

The last decade has witnessed dramatic developments in molecular biology to a point where it is now possible for genetic engineers to consider programmes aimed at isolating and cloning specific genes from any genomic source for introduction into the germ line of other organisms. The impact of this technology on livestock breeding is potentially revolutionary.
Abnormal fluid transport by the epididymis as a cause of obstructive azoospermia
Authors: Wong PY
Published: October 2005

It has been known for more than a decade that in many mammalian species including man, spermatozoa once shed from the testis are immature, immotile and incapable of fertilizing the ovum. During their transit through the epididymis, they undergo various morphological and functional changes that confer on them the ability to ascend the female tract, to undergo an acrosome reaction, to penetrate the zona pellucida and to effect a successful fertilization. By the time spermatozoa have reached the cauda epididymidis, they are held in a quiescent state by factors in the epididymal fluid. The epididymis plays a vital role by creating a favourable fluid environment for sperm maturation and storage. The exact mechanisms underlying sperm maturation and storage are unclear and it appears that no single epididymal factor is held entirely responsible. In contrast, spermatozoa are directly bathed in the epididymal fluid; the fluidity of the microenvironmental has a direct effect on epididymal spermatozoa. The epididymal epithelium has been shown to transport electrolytes and water by processes involving ion pumps, ion carriers and ion channels. These components are under nervous, hormonal and paracrine control and are susceptible to interference by pharmacological agents. This paper reviews the physiology of electrolytes and fluid transport in the epididymis and describes how abnormal fluid transport across the epididymal duct could predispose towards epididymal obstruction, a condition that may occur in cystic fibrosis, Young's syndrome or other unexplained cases of male infertility.
Immunocytochemical localization of prostaglandin synthase in the ovine uterus during the oestrous cycle and in early pregnancy
Authors: Salamonsen LA , Findlay JK
Published: October 2005

Prostaglandin (PG) synthase has been localized by immunocytochemistry within the ovine uterus throughout the oestrous cycle and in early pregnancy. On Day 4 of the cycle, PG synthase was located primarily in the stromal cells in caruncular and intercaruncular tissue with little staining in the epithelium. On Days 14 through to 16, the most intense staining was in the luminal epithelial cells (caruncular and intercaruncular) and in epithelial cells of glands close to the uterine lumen. PG synthase was also located in the intercaruncular stromal cells, particularly close to the myometrium. Staining for the enzyme on Day 10 was intermediate between that of Day 4 and Day 14. On Day 15 of pregnancy, the pattern of staining was identical to that on Day 15 of the cycle, with no detectable difference in intensity. When endometrial cells (cycle, Day 14) were cultured with and without ovine trophoblast protein-1 (3 ng mL-1) in vitro, release of PGE and PGF2 alpha was attenuated (54% and 47% of control respectively) but no differences were observed in the intensity of staining for PG synthase in the cells. These results demonstrate marked cyclical changes in the endometrial cell types producing PGs, suggesting differential regulation of PG synthase. In addition, it appears that conceptus-induced changes in PGF2 alpha release do not occur via changes in the concentration or cellular localization of PG synthase, but rather that the activity of the enzyme is modified.
Identification of inhibin and inhibin-related proteins in human follicular fluid
Authors: Robertson DM , Foulds LM , de Vos F , Leversha L , de Kretser DM
Published: October 2005

Inhibin-related proteins were identified in human follicular fluid following fractionation by gel permeation chromatography under neutral and acidic conditions, reversed-phase high performance liquid chromatography (HPLC) and preparative polyacrylamide gel electrophoresis. A number of molecular mass forms of inhibin (30-36 and 59-66 kDa) based on their in vitro biological and immunological activities were identified, of which 59-66 kDa inhibin was the predominant form. Bioactive fractions devoid of inhibin immunoactivity were also identified with molecular masses of 46 and 55 kDa. Based on their retention positions on reversed-phase HPLC and their lack of inhibin immunoactivity, these proteins are likely to be follicle stimulating hormone (FSH) suppressing proteins/follistatins previously identified in bovine and porcine follicular fluids. In addition, an immunoactive inhibin fraction devoid of bioactivity was identified in large amounts in the 50-70 kDa region of the gel permeation chromatogram at neutral pH. This material, based on previous findings with the fractionation of bovine follicular fluid, is likely to be the alpha-inhibin subunit precursor protein. No FSH stimulating activity (activin) was identified in any of the chromatograms, suggesting that the levels of activin in human follicular fluid are low. In conclusion, inhibins of molecular mass 30, 36, 59 and 66 kDa have been identified in human follicular fluid. Proteins with inhibin bioactivity devoid of immunoactivity and vice versa have also been detected and these proteins are probably FSH suppressing protein and an alpha-inhibin subunit precursor protein. Activin could not be identified.
Progesterone receptor antagonists and prostaglandins in human fertility regulation: a clinical review
Authors: Healy DL
Published: October 2005

Progesterone receptor antagonists have been developed by substitutions at the 11-beta and 17 side-chain positions of the progestagen norethisterone. The most studied progesterone receptor antagonists are mifepristone (Mifegyne; Roussel-UCLAF; RU486) and ZK98734 and ZK98299 (Schering AG). These compounds bind avidly to the progesterone receptor and glucocorticoid receptor but have essentially no binding to the mineralocortocoid, oestrogen or androgen receptors. Mifepristone also binds avidly to albumin, resulting in a half-life of approximately 24 h after oral administration. Progesterone receptor antagonists can induce menstruation by a direct action upon the endometrium. They have also been shown to exert weak progesterone agonist actions in certain circumstances and to modulate pituitary hormone secretion by antagonizing the feedback actions of progesterone. Moreover, they release prostaglandin F2 alpha and E2 from human endometrium or early pregnancy decidua and reduce the metabolism of these eicosanoids. Clinically, progesterone receptor antagonists have been used in trials of menstrual regulation, abortion and induction of labour, and during treatment of breast or ovarian cancer, some forms of hypertension and meningioma. Progesterone receptor antagonists have been administered to approximately 70,000 women in 18 countries as medical abortifacients. They have been proven, especially when combined with prostaglandin analogues, to be as effective as surgical methods of termination of pregnancy. Progesterone receptor antagonists have focussed international attention on menstrual regulation, abortion and the rights of women to regulate their fertility.
Phospholipases in human parturition
Authors: Wilson T
Published: October 2005

Phospholipase A2 plays a major role in controlling PG synthesis. Regulation of the activity of this enzyme probably holds the key to the onset of labour. Both PLA2 and PLC can contribute to arachidonate release and PG production in cells, but PLA2 appears to be the main role of synthesis. Phospholipase A2 and PLC can be activated independently of each other; an influx of external calcium is required for PLA2 activation. It is suggested that PLC contributes to PG synthesis through product stimulation of protein kinase C which maintains a pool of free arachidonate by inhibiting reincorporation into the cell membrane. The regulatory role for lipocortin in phospholipase inhibition is controversial and unlikely to be relevant to the onset of labour.
Is human labour triggered by an increase in the rate of synthesis of prostaglandin G/H synthase?
Authors: Gaffney RC , Rice GE , Brennecke SP
Published: October 2005

The increase in the synthesis of prostaglandins by intrauterine tissues which occurs at the time of parturition may be the consequence of periparturient changes in several regulatory pathways. The aim of this study was to determine whether changes in the rate of synthesis of prostaglandin G/H synthase (PGHS) contribute to the labour-associated increase in prostaglandin synthesis by human chorioamnion and placenta. The rate of recovery of prostaglandin E2 (PGE2) synthesis following inhibition of PGHS by aspirin was used as an estimation of PGHS resynthesis. In tissues obtained following spontaneous delivery, the half-time recovery of PGE2 synthesis was 3.5 to 6.0-fold less (P less than 0.001; n = 5) than the half-time recovery observed in tissues obtained before the onset of labour. These data suggest that a periparturient increase in the rate of synthesis of PGHS contributes to enhanced prostaglandin synthesis at term.
Decreased collagen concentration in rat uterine implantation sites compared with non-implantation tissue at days 6-11 of pregnancy
Authors: Myers DB , Clark DE , Hurst PR
Published: October 2005

Collagen concentrations at implantation sites in the rat uterus were found to be significantly decreased compared with concentrations in adjacent non-involved uterine tissue in early pregnancy (75% by Day 11). The decrease in collagen was most marked in primary decidua and was also observed to a lesser extent (20%) in myometrium at the implantation site. There was a decrease of 20% in the concentration of total proteins at Day 7 (as measured by the ninhydrin method) and a slight increase in water content (2%) at Days 6 and 7. The differences in total protein and water content were transient, but the difference in collagen was maintained throughout early pregnancy. The localized changes in collagen content observed in this study, along with previously reported morphological changes in fibrillar and basement-membrane collagens in the uterus, give support to a theory of remodelling in early pregnancy involving simultaneous synthesis and degradation of extracellular proteins during decidualization.
Rapid cryopreservation of sheep embryos by direct transfer into liquid nitrogen vapour at -180 degrees C
Authors: Szell A , Zhang J , Hudson R
Published: October 2005

The in vitro survival of control and rapidly cryopreserved sheep embryos was examined as a function of the duration of exposure to a vitrification medium (25% glycerol + 25% propylene glycol). Embryos in late morula to late blastocyst stages were permeated by a mixture of 10% glycerol + 20% propylene glycol for 10 min at 18-23 degrees C and then exposed to the vitrification medium for 0.5, 1, 2 or 4 min at 18-23 or 4-12 degrees C. The cryoprotectants were removed without cryopreservation (control embryos) or after rapid cryopreservation by direct transfer into liquid nitrogen vapour at -180 degrees C. The duration of exposure to the vitrification medium at 18-23 degrees C affected the in vitro survival rate of control embryos (P = 0.06) but had no effect on the survival of rapidly cryopreserved embryos. However, at 4-12 degrees C the duration of exposure affected the survival of cryopreserved embryos (0.5 min: 64%, 18/28; 1-4 min: 43%, 34/80; P = 0.074). Overall, the in vitro survival rate of control and cryopreserved embryos increased with advancing development from late morulae (36%) to late blastocysts (70%). The in vivo survival of embryos that had been exposed to the vitrification medium for 0.5 min at 4-12 degrees C and then vitrified was tested. The rate of development to term was 11% (4/35) for late morulae or early blastocysts and 32% (6/19; P greater than 0.1) for blastocysts to hatching blastocysts. These results showed that sheep embryos can be successfully cryopreserved by a simple, rapid procedure.
Developmental capacity of mechanically bisected mouse morulae and blastocysts
Authors: Wang ZJ , Trounson A , Dziadek M
Published: October 2005

Mouse embryos were mechanically bisected at the morula, early blastocyst or expanded blastocyst stages of development and cultured in vitro to the expanded blastocyst stage. Their capacity for postimplantation development was assessed after transfer to pseudopregnant foster mice. Embryos bisected at blastocyst stages had a higher survival rate in vitro than those bisected at the morula stage. Half-embryos had approximately half the number of cells at the blastocyst stage as control embryos, but the proportion of cells in the inner cell mass (ICM) was unaltered. The implantation rate of blastocysts derived from bisected embryos was only slightly lower than that of control embryos, but bisected embryos had a significantly reduced capacity to form fetuses. Histological analyses showed that failure to form a fetus is due to the absence of egg cylinder development, which correlates with the reduced number of cells in the ICM of bisected embryos. Postimplantation viability of half-embryos was significantly higher when blastocysts were transferred to Day-3 rather than Day-4 pseudopregnant recipients, presumably because of an increase in cell number in vivo prior to implantation.
The placenta, prostaglandins and parturition: a review
Authors: Thorburn GD
Published: October 2005

It is proposed that in sheep, during the last third of gestation, a progressive increase in the production of prostaglandin E2 (PGE2) by the fetal trophoblast activates the fetal hypothalamic-pituitary-adrenal axis leading to an increase in fetal cortisol concentrations. High cortisol levels increase placental 17 alpha-hydroxylase activity causing a decrease in maternal progesterone concentrations and an increase in oestrogen concentrations. The increase in the E/P ratio results in an increase in PGF2 alpha release from the maternal placenta, increased uterine activity and parturition. The increased production of PGE2 by the placenta has been linked to the rapid increase in the growth of the fetus from day 110 of gestation onwards. It is speculated that the growth pattern of the fetus represents a genetically programmed 'clock' which acts by stimulating placental PGE2 production leading to maturation of key organ systems in the fetus and finally parturition.
Pace-maker activity in the myometrium of the oestrous rat: in vivo studies using video-laparoscopy
Authors: Crane LH , Martin L
Published: October 2005

Female rats had one oviduct, or the cranial tip of one or both uterine horns, lesioned by coagulation, or separated from the remainder of the uterus. After recovery and return to oestrous cycles, myometrial activity at oestrus was analysed by video-laparoscopy. Lesioning the oviduct had no effect on myometrial activity. Coagulating the cranial tip of one horn initially reduced the frequency of ipsilateral longitudinal contractions propagating caudally, but this returned to normal after 14 days. Separating the cranial tip of the uterus had permanent effects on myometrial activity. Separation of one tip reduced the frequency of ipsilateral longitudinal contractions propagating caudally, had no effect on ipsilateral contractions propagating cranially, but reduced the frequency of contralateral contractions propagating cranially. The effect of a lesion near one uterotubal junction on contractions originating contralaterally near the cervix results from communication between uterine horns at the cervical junction; arrival of a caudally propagating contraction in one horn frequently generates a cranially propagating contraction in the other. Separating both uterine tips reduced the frequency of longitudinal contractions propagating in both directions. We conclude that, at oestrus, most spontaneous myometrial contractions are generated by pace-makers in the cranial tip of each uterine horn. The pace-makers are close to the uterotubal junction and regenerate after destruction by coagulation. When their influence is permanently removed, new pace-makers do not develop in myometrium caudal to the lesion. We conclude that most myometrial cells do not exhibit spontaneous pace-maker activity in vivo.
Relaxin and relaxin c-peptide levels in human reproductive tissues
Authors: MacLennan AH , Grant P , Borthwick AC
Published: October 2005

A radioimmunoassay for a representative portion of the c-peptide of human relaxins (H1 and H2) was developed and validated. Relaxin c-peptide is present in preprorelaxin and prorelaxin, and exists free after the maturation of relaxin is completed. The aim of the study was to identify possible production and storage sites of human relaxin by comparing c-peptide and relaxin levels in various human reproductive tissues. c-Peptide immunoreactivity was present in the corpus luteum, amniochorion, decidua and seminal plasma; this indicates that these tissues may be relaxin production sites. Relaxin was detected in the corpus luteum, amniochorion, decidua, trophoblast, seminal plasma, myometrium and fibroids. This suggests that these tissues are storage and/or target sites for relaxin. The highest concentration of relaxin was detected in decidua at term. This level decreased after labour. The concentrations of c-peptide and relaxin were approximately equimolar in serum during pregnancy. This study lends support to the concept that relaxin is produced and stored at extra-luteal sites; these sites of hormone production support a paracrine role for relaxin during pregnancy.
A simple rapid 4.5 M dimethyl-sulfoxide freezing technique for the cryopreservation of one-cell to blastocyst stage preimplantation mouse embryos
Authors: Shaw JM , Diotallevi L , Trounson AO
Published: October 2005

This study applies a 4.5 M dimethyl-sulfoxide freezing procedure, developed for 2-cell mouse embryos, to pronuclear to hatched blastocyst stage mouse embryos. The embryos were plunged into liquid nitrogen after 3 min equilibration at room temperature, or 3-60 min equilibration at 0 degrees C. Equilibration at 0 degrees C gave survival rates as high as or higher than rates after equilibration at room temperature. Optimal blastocyst formation, or re-expansion, rates for embryos frozen after equilibration at 0 degrees C were 76% for pronuclear stage embryos and 96-100% for 2-cell to mid-blastocyst stage embryos. The optimal rates of fetus formation, per embryo frozen, ranged from 62 to 88% for pronuclear to mid-blastocyst stage embryos. These results compared favourably with non-frozen control embryos (80-100% blastocyst formation, and 67-78% fetus formation).
Effects of season, GnRH administration and lupin supplementation on the ovarian and endocrine responses of merino ewes treated with PMSG and FSH-P to induce superovulation
Authors: Jabbour HN , Ryan JP , Evans G , Maxwell WM
Published: October 2005

Administration of gonadotrophin releasing hormone (GnRH) 24 h after sponge withdrawal did not affect the numbers of corpora lutea (CL) or persistent large follicles (LF) in ewes superovulated with 400 I.U. pregnant mare serum gonadotrophin and 12 mg follicle stimulating hormone in spring (11.6 +/- 0.9 v. 13.0 +/- 0.9 CL and 0.8 +/- 0.9 v. 0.9 +/- 0.3 LF, for +GnRH and -GnRH ewes, respectively). However, it did increase the ovulatory response of ewes superovulated in autumn (15.8 +/- 1.2 v. 11.8 +/- 1.1 CL). The incidence of ewes with prematurely regressed CL was also greater in autumn than in spring (21/89 v. 5/88). Supplementary feeding with lupin grain in autumn had no effect on numbers of CL but did increase the incidence of ewes with LF (18/48 v. 7/46) and caused a marked reduction in the incidence of ewes with regressed CL (1/44 v. 20/45). For ewes treated in autumn, there were no effects of lupin supplementation or GnRH administration on peak oestradiol-17 beta (E2) or peak luteinizing hormone (LH) levels. However, when peak E2 concentrations in the plasma were adjusted for numbers of preovulatory follicles, higher concentrations were observed for ewes in the +lupin/-GnRH group (12.4 +/- 2.9 pg mL-1) than in other treatment groups (range 4.3 +/- 0.4 to 5.7 +/- 0.3 pg mL-1). Moreover, the time of the LH peak was advanced by both lupin supplementation and GnRH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Some effects of feeding Tribulus terrestris, Ipomoea lonchophylla and the seed of Abelmoschus ficulneus on fetal development and the outcome of pregnancy in sheep
Authors: Walker D , Bird A , Flora T , O'Sullivan B
Published: October 2005

Pregnant ewes and their fetuses were chronically catheterized using aseptic procedures under general anaesthesia, and the ewes were then fed either lucerne chaff alone, or lucerne mixed with dried plant material obtained from one of three forb species, Tribulus terrestris (caltrop), Abelmoschus ficulneus (native rosella) or Ipomoea lonchophylla (cowvine), from 103-112 days gestation until term. Ingestion of the forb material was not associated with changes in maternal blood gases, plasma glucose concentrations, or the length of gestation. However, ingestion of rosella seed was associated with a significantly greater fall of fetal arterial pO2 with advancing gestation, and ingestion of either rosella or cowvine was associated with significantly lower fetal mean arterial pressure at 127-131 days, compared with the Tribulus and lucerne groups. Also, the incidence of fetal breathing movements was significantly lower, and did not show a normal day-night variation, in each of the forb-fed groups compared with the lucerne-fed group. The results indicate that these forb plants may contain substances that affect the functional development of the fetal brain. Although ingestion of these plants did not appear to affect the outcome of pregnancy in this study, the possibility that these forbs have a greater impact in sheep populations with poor nutrition and in more extreme environmental conditions is discussed.
Oviductal fluid protein patterns in the rhesus monkey (Macaca mulatta) during the menstrual cycle
Authors: Paliwal A , Malaviya B , Kamboj VP
Published: October 2005

Oviducts were obtained from monkeys on Days 8, 14, 19 and 25 of the menstrual cycle and changes in the pattern of luminal fluid proteins were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Densitometric analysis after periodic acid Schiff's reagent (PAS) and coomassie blue staining of the gels revealed 85 and 95 kDa proteins only up to Day 14 whereas a 130 kDa glycoprotein persisted up to Day 19 and reached a nadir at mid-menstrual cycle (Day 14). The absence of the 130 kDa glycoprotein in the serum and its presence in cytosolic preparations up to Day 19 suggest that it is of oviductal origin. The 130 kDa glycoprotein is of particular interest since it was present in the oviductal fluid during mid cycle, a period when the oviduct participates in gamete transport, fertilization and embryo development. The conclusion drawn from this study is that the protein profile of monkey oviductal fluid changes during the menstrual cycle.
Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia)
Authors: Chaturapanich G , Jones RC , Clulow J
Published: October 2005

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.
Evaluating an in vitro culture system of bovine uterine and oviduct epithelial cells for subsequent embryo co-culture
Authors: Thibodeaux JK , Myers MW , Goodeaux LL , Menezo Y , Roussel JD , Broussard JR , Godke RA
Published: October 2005

Three experiments were conducted to evaluate the effects of culture medium and incubation temperature on bovine uterine and oviduct epithelial cell growth, so that the most efficient combination could then be used to develop a co-culture system for bovine embryos. In the first experiment, uterine and oviduct epithelial cells at either the second or third subpassage were incubated for 8 days at 37 degrees C with 5% CO2 in Tissue Culture Medium-199, CMRL-1066, Minimal Essential Medium, Menezo's B2 or Ham's F-12 medium. In addition to plotting growth curves of cell populations, the cell cycle was monitored for 8 days by flow cytometry. Uterine and oviduct epithelial cells incubated in CMRL-1066 exhibited the highest growth rates during the 8-day culture period. However, there were no differences in cell cycle analysis among treatment groups during the incubation period. In the second experiment, CMRL-1066 medium was used to evaluate growth and proliferation of uterine and oviduct epithelial cells incubated at 37 degrees C or 39 degrees C; temperature had no significant effect on growth rates or proliferation rates for either uterine or oviduct cells during the 8-day incubation. In the third experiment, the more promising culture media for epithelial cell culture studies were chosen for in vitro maturation and subsequent in vitro fertilization (IVF) of bovine oocytes. Early cleavage-stage embryos produced by IVF procedures were subsequently cultured in vitro for 7 days in medium alone or with oviduct epithelial cells. In this study, the culture medium did not influence fertilization or cleavage rates. However, more embryos co-cultured with oviduct epithelial cells were considered viable after 7 days of incubation compared with embryos incubated in medium alone. These results indicate that various incubation conditions can influence the growth of bovine uterine and oviduct epithelial cells in vitro. However, in spite of changes in cell growth patterns, there does not appear to be a change in their embryotropic capabilities in vitro.
GIFT or IVF for patients with patent fallopian tubes?
Authors: Weiss TJ
Published: October 2005

The pregnancy rate in a group of 39 couples who underwent in vitro fertilization (IVF) with donor sperm was compared with that of couples undergoing gamete intra-Fallopian transfer (GIFT) over the same period (31 December 1986 to 30 June 1991). The diagnostic status of the female partners in each group was qualitatively similar. The women had patent Fallopian tubes, mild endometriosis or minor tubal adhesions. The male partners in the GIFT group had normal or marginally abnormal semen parameters which were considered to be comparable to the post-thaw quality of the semen used in donor insemination (DI). The mean age of the women in the DI group was 32 years (range 25-40) which was similar to that in the GIFT group [32 years (24-39)]. The women in the IVF group had undergone a mean of eight cycles of DI before proceeding to treatment with IVF. There was no difference between the pregnancy rate in the two groups (log-rank test). These observations advance the proposition that IVF should be reconsidered as an effective treatment for women with patent Fallopian tubes.
Development of the Technique of Oocyte Donation
and Hormonal Replacement Therapy:
is Oestrogen Really Necessary for the Establishment
and Maintenance of Pregnancy?
Authors: Trounson A
Published: October 2005

The technique for oocyte donation to women with hypergonadotrophic hypogonadism was modelled
on the requirements for ovarian steroid replacement therapy in ovariectomized ewes. In the sheep,
it is apparent that a period of priming progesterone, follicular-phase oestrogen and luteal-phase
progesterone is required to enable embryo development following embryo transfer; the timing of embryo
transfer is governed by the actual dose of luteal-phase progesterone. The horse, on the other hand,
requires only progesterone to establish a receptive uterus for transferred embryos. Although a sequential
regimen of oestrogen and progesterone that mimics the hormonal profiles in a normal menstrual cycle
is very efficient in effecting pregnancy by oocyte donation in women, much simpler regimens have been
devised that produce a variable-length follicular phase by using a constant dose of oestrogen and a
constant dose of progesterone for the luteal phase and early pregnancy. It is suggested that ovarian
oestrogen is not essential for the luteal phase and early pregnancy, and may not even be required for
the establishment of pregnancy. It is also apparent that progesterone replacement may cease before
the luteoplacental shift is detected, without necessarily interrupting pregnancy, suggesting that local
embryo or placenta-derived steroids may effectively maintain early pregnancy in the human.
Supersensitivity to the stimulant action of noradrenaline on human myometrium near term
Authors: Pennefather JN , Paull JD , Story ME , Ziccone SP
Published: October 2005

Noradrenaline (10-50 nM) and tyramine (0.05-1 mM) enhanced contractile force elicited by field stimulation of strips of myometrium from non-pregnant and pregnant women. In higher concentrations, noradrenaline produced sustained contractions. The EC50 values for noradrenaline were 0.4 microM in tissues from pregnant women and 3.1 microM in tissues from non-pregnant women; maximum responses were greater in the former tissues. In addition, the effects of noradrenaline on myometrium from pregnant women were more marked on the inner layer than on the outer layer, antagonized by the alpha 1-adrenoceptor antagonist prazosin (0.1 and 1.0 microM), and unaffected by the inhibitor of neuronal uptake, nisoxetine (0.1 microM). Taken together, these observations confirm that supersensitivity to noradrenaline develops during pregnancy and is present near term. The supersensitivity to noradrenaline at term can be attributed only in part to a decrease in its removal by the sympathetic innervation, which declines towards term, because responses to tyramine were also enhanced in tissues from pregnant women. It is possible that gap junction formation may also contribute to this supersensitivity.
Catabolic utilization of glucose by the sheep conceptus between days 13 and 19 of pregnancy
Authors: Wales RG , Waugh EE
Published: October 2005

The production of carbon dioxide and lactate from glucose by sheep embryos and samples of extraembryonic membranes was measured during a 2.5 h incubation period. Both embryos and their membranes were active in the glycolytic and oxidative utilization of glucose and, in general, the utilization of glucose per unit weight fell as development progressed from Day 13 to Day 19 of pregnancy. Both oxidation of glucose and glycolysis by the extraembryonic tissues, expressed as activity per microgram dried tissue, fell progressively with development. The rate of decline in CO2 production was greater than the rate for glycolysis and, as a consequence, the contribution of glycolysis to the estimated energy yield from the catabolism of glucose rose with time. In the embryo, both glucose oxidation and glycolysis peaked on Day 15 with estimates of adenosine triphosphate (ATP) production from glucose per microgram dried tissue on this day being 50% above those on Day 13 and 100% above those on Day 17. In general, the estimated yields of ATP from glucose were similar for structures of the same developmental age except that, at Day 19, it was calculated that the rate of ATP production by embryos was double that by the extraembryonic membranes. In incubations using 5.56 mM glucose as sole exogenous energy source, glucose turnover by embryos and embryonic membranes tended to be higher in a bicarbonate-buffered medium than in HEPES (4-(2-hydroxyethyl)-1-piperazincethane sulfonic acid) and phosphate-buffered media. As a result, the estimate of ATP yield plus the contribution of oxidative pathways to this yield were significantly higher in this medium than in the others. Glucose turnover by the embryo and its membranes in bicarbonate-buffered medium containing 0.56 mM glucose plus the alternate substrates, lactate and pyruvate, was severely depressed. Further experiments using samples of trophoblast and yolk sac indicated that both reduction in glucose concentration and the presence of the other substrates contributed to this suppression. Furthermore, an interaction between these factors was evident with the effects of alternative substrates being exaggerated when glucose concentration was low.
Anti-sperm antibodies and semen profiles in re-anastomosed men
Authors: Kay DJ , Clifton V , Taylor JS , Boettcher B
Published: October 2005

A group of 29 re-anastomosed men were examined with respect to semen quality, anti-sperm antibody titres in serum and seminal plasma, presence of anti-sperm antibodies on sperm, and success rate in inducing pregnancy. Results indicated no association between pre-reversal serum anti-sperm antibody titres and post-reversal semen quality, but a pregnancy induction rate of zero was associated with serum anti-sperm antibody titres greater than 160. It is recommended that men considering reversal, with anti-sperm antibody titres of this level, should receive counselling about the possibility of post-reversal infertility.