Low frequency ultrasonic propagation through fibre reinforced, polymer composites.

This paper concentrates upon mesoscale variations observed in the time-of-flight (TOF) area scans of shear wave propagation through 'identically processed', injection moulded, glass fibre reinforced, polypropylene plaques. The effect of these structural variations on the derived 3D stiffness constants is discussed. Hence the random measurement errors associated with the stiffness constant measurements are differentiated from the intrinsic process-induced spatial variations. Interesting correlations between TOF and received amplitudes of shear wave propagation have been found and our tentative interpretation of these data in terms of mesostructural variations in the reinforcing fibre locations and fibre orientations is presented.

Assessment of three levels of folic acid on serum folate and plasma homocysteine: a randomised placebo-controlled double-blind dietary intervention trial.

OBJECTIVE: To determine the minimum effective dose of folic acid required to appreciably increase serum folate and to produce a significant reduction in plasma total homocysteine (tHcy). DESIGN: Double-blind, randomised placebo-controlled intervention trial. SETTING: Community-based project in a New Zealand city. SUBJECTS: Seventy free living men and women with tHcy> or =10 micromol/l. Mean age (range) was 58 (29-90) y. INTERVENTIONS: Daily consumption over 4 weeks of 20 g breakfast cereal either unfortified (placebo) or fortified with 100, 200 or 300 microg folic acid. Dietary intake was determined by weighed diet records and consumption of commercially fortified products was avoided. MAIN OUTCOME MEASURES: Plasma tHcy and serum folate concentrations. RESULTS: Average serum folate concentrations (95% CI) increased significantly in the treatment groups relative to the control group by 28(9-51)%, 60(37-87)% and 79(51-114)% for supplementation with 100, 200 and 300 microg folic acid, respectively. A reduction in tHcy was observed, being 16(8-22)%, 12(4-18)% and 17(9-24)% in the three treatment groups, respectively. CONCLUSIONS: A regular intake of as little as 100 microg folic acid per day was sufficient to lower tHcy in persons at the upper end of the normal range for tHcy. Low-level fortification may also be appropriate for lowering the risk of neural tube defects given that, when aggregated from all sources, the total intake of folic acid may be sufficiently high to adequately improve the folate status of young women.

Leukemia inhibitory factor, leukemia inhibitory factor receptor, and glycoprotein 130 in rhesus monkey uterus during menstrual cycle and early pregnancy.

This goal of this study was to examine immunohistochemical distribution of leukemia inhibitory factor (LIF), LIF receptor (LIFR), and glycoprotein (gp) 130 in rhesus monkey uterus during the menstrual cycle and early pregnancy. Pregnancy rate was significantly reduced in the control group from 66.7% (12 of 18) to 22.2% (4 of 18) with an injection of goat anti-human recombinant LIF immunoglobulin G into the uterine lumen on Day 8 of pregnancy. LIF was mainly localized in glandular and luminal epithelium. LIF immunostaining during the luteal phase was stronger than it was during the proliferative phase. LIF staining gradually increased from Day 3 of pregnancy and reached its highest level on Day 9. LIFR was mainly localized in the glandular and luminal epithelium. LIFR staining during the luteal phase was stronger than it was during the proliferative phase. LIFR staining began to increase from Day 3 of pregnancy and reached a high level on Days 9 and 11. Gp130, a signal-transducing receptor component of LIF, was mainly localized in the glandular epithelium. A high level of gp130 was found on Days 16 and 20 of menstrual cycle, and from Days 5 to 11 of pregnancy. These results suggest that LIF may play an important role in monkey implantation, as it does in mice.

Epidermal growth factor family in rhesus monkey uterus during the menstrual cycle and early pregnancy.

This study examines immunohistochemically the presence of EGF, TGFalpha, HB-EGF, AR, and EGFR, members of the EGF family in the monkey uterus during the menstrual cycle and early pregnancy. EGF, TGFalpha, HB-EGF, AR, and EGFR were mainly localized in glandular and luminal epithelium. TGFalpha, HB-EGF, and AR staining were stronger in the glandular epithelium closer to the myometrium than in that closer to the luminal epithelium. The level of EGF, TGFalpha, HB-EGF, AR, and EGFR staining was low on days 1 and 6, and began to increase on day 9 of the menstrual cycle. A high level of EGF, and EGFR staining was maintained on days 16, 20, and 25 of the menstrual cycle. The highest levels of TGFalpha, AR, and HB-EGF staining were seen on days 16 and 20 of the menstrual cycle. In early pregnancy, a low level of EGF, TGFalpha, HB-EGF, AR, and EGFR staining appeared on days 1 and 2 of pregnancy, and then gradually increased from day 3 of pregnancy. The highest levels of EGF, TGFalpha, HB-EGF, and EGFR were detected on days 9, and 11 of pregnancy. Our data suggest that the EGF family may play a role in monkey implantation. Mol. Reprod. Dev. 55:164-174, 2000.

The promise of public/private sector collaboration in the development of new contraceptives: the experience of CICCR.

The Consortium for Industrial Collaboration in Contraceptive Research (CICCR) was established in 1995 with funding from two philanthropic foundations. Now just over 3 years later, it is supported by five foundations and a United Nations agency. Work in three priority areas of male methods, vaginal methods and monthly methods for women is progressing well. Collaboration with 10 industrial entities has been established, and more than 60 contracts with investigators at not-for-profit institutions have been funded. It can be concluded that CICCR has provided an efficient and effective mechanism for promoting industrial collaboration in contraceptive R&D, and fills a need not covered by other agencies active in the field.

The promise of public/private sector collaboration in the development of vaginal microbicides.

This paper describes the efforts of the public sector, primarily the CONRAD Program and its Consortium for Industrial Collaboration in Contraceptive Research (CICCR), to work with industry in the development of vaginal microbicides for the prevention of transmission of STDs including HIV. The results of a meeting on this topic held in Durham, NC, USA in October 1998, as well as market surveys, are also included. The projects described illustrate the opportunities for collaboration and the resulting progress.

Pushing the frontiers of science--the Mellon reproductive biology centers.

The 20-year history of the Andrew W. Mellon Foundation's support for US reproductive biology centers and junior investigators is summarized. The main results of the Foundation's program during the 1990s are described under the following headings: research generated by seed money, research generated by the twinning program, and commercial partnerships. The twinning program supports research collaborations between US centers and reproductive biology centers in developing countries, and was recently reviewed by an external panel. Both the seed money and twinning mechanisms were judged to have been successful in promoting research relevant to contraception which, in many instances, resulted in publications in peer-reviewed journals and in follow-on funding from other sources. The Foundation established a new program in 1998. The paper lists the US centers included in the new program and the 'target' areas of research that will be emphasized.

Differential hormonal regulation of leukemia inhibitory factor (LIF) in rabbit and mouse uterus.

Leukemia inhibitory factor (LIF) has been shown to be essential for the implantation of mouse blastocysts. The present study was designed to determine how LIF protein was hormonally regulated in rabbit and mouse uterus using immunohistochemistry. In unmated rabbits, LIF protein was at a low level in the uterine epithelium and glands, and up-regulated by progesterone alone or estradiol-17 beta and progesterone combined. Estradiol-17 beta alone had no apparent effect. In ovariectomized mice, the level of LIF protein was very low in the uterine epithelium and glands, and was up-regulated by estradiol-17 beta alone or estradiol-17 beta and progesterone combined. Progesterone alone had no apparent effect. These results suggest that LIF protein is differentially regulated in rabbit and mouse uterus by progesterone and estrogen, respectively. This would explain the high level of LIF protein observed in uterine epithelium and glands prior to blastocyst implantation in the two species with different hormonal requirements for implantation.

Localization of leukemia inhibitory factor in human endometrium during the menstrual cycle.

Leukemia inhibitory factor (LIF) has been shown to be imperative for the implantation of mouse blastocysts. The objective of this study was to examine the pattern of LIF protein in the human endometrium during the menstrual cycle. A low level of LIF was detected in endometrial glands during the proliferative phase. During the luteal phase, LIF staining in the glands appeared stronger in the mid- and late luteal phase than immediately after ovulation. However, a low level of LIF was detected in the stromal cells during the early and midproliferative phase, while only a minimal level was observed during the late proliferative and luteal phases.

Leukemia inhibitory factor, LIF receptor, and gp130 in the mouse uterus during early pregnancy.

Leukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to investigate the changes of LIF protein, LIF receptor, and gp130 in the mouse uterus during the early pregnancy. LIF protein and LIF receptor were at high levels in the mouse uterus near the time of ovulation and on day 4 of pregnancy. gp130 was highest on days 3 and 4 of pregnancy. Both LIF receptor and gp130 showed strong staining in the stroma of the day 5 uterus, at a time when LIF protein was low. The presence of LIF receptor and gp130 in the luminal epithelium on day 4 and in the stroma on day 5 may indicate the site of the high affinity LIF receptor. The coexistence of a high level of LIF protein, LIF receptor, and gp130 in the day 4 uterus is consistent with the previously observed high level of uterine LIF mRNA on the same day and the importance of LIF for the blastocyst implantation in mouse.

Differential metabolism of exogenous platelet-activating factor by glandular epithelial and stromal cells of rabbit endometrium.

Significant changes in platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) concentration have been observed in rabbit endometrium during the preimplantation period, but, under in vitro conditions, constitutive PAF biosynthesis by isolated endometrial tissues was not easily demonstrable. Relative changes in enzymes involved in the synthesis and metabolism of PAF in the tissues may account for this disparity. In addition, during this period of preimplantation, marked changes in PAF receptor concentration have been noted. The present study examines the factors that may modulate the metabolism of exogenous [3H]PAF in the endometrium of rabbits on day 6 of pregnancy. Since preferential [3H]PAF binding in situ by the glandular epithelial, but not by the stromal, cells was demonstrated, their cell-specific metabolism of exogenous [3H]PAF was also examined. After entry into the endometrial cell, [3H]PAF was rapidly metabolized by the sequential action of cytosolic Ca(2+)-independent acetylhydrolase to [3H]lyso-PAF and this was in turn acylated by membrane-associated transacylase to [3H]alkylacyl-glycerylphosphorylcholine. PAF resynthesis was not observed and, in stromal cells, there was a significant build-up of [3H]lyso-PAF, suggesting that lyso-PAF:acetyl-CoA acetyl-transferase may be a limiting factor. In the glandular epithelial cells, however, there was a significant accumulation of a neutral lipid without a significant build-up of [3H]lyso-PAF or [3H]PAF. The neutral lipid co-migrated with the product of phospholipase C-catalysed metabolism of PAF and authentic 1-O-hexadecyl-2-acetyl-glycerol. In addition, the elution times of phospholipase C digestion of C18 PAF and the neutral lipid produced by cellular metabolism of [3H]PAF, determined by gas chromatography/flame ionization detection, were similar. It seems that it is the synthesis of the neutral lipid from reacetylated [3H]lyso-PAF that prevented [3H]PAF accumulation under in vitro conditions. This is the first documentation of the synthesis of this lipid in the mammalian uterus. The lipid may serve as the precursor for de novo PAF synthesis in the glandular epithelial cells during endometrial proliferation.

Stimulation of prostaglandin (PG) F2 alpha and PGE2 release by tumour necrosis factor-alpha and interleukin-1 alpha in cultured human luteal phase endometrial cells.

Tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) are important mediators of cell signalling in the uterus. Prostaglandins (PG) have been implicated in the increase of endometrial vascular permeability which occurs during the implantation process. This study evaluates the effect of these two pleiotropic cytokines on PGF2 alpha and PGE2 release from human luteal phase endometrial glandular epithelial cells (GEC) and stromal cells (STC) in culture. Basal PGF and PGE release did not differ significantly from each other or among cell types, and declined significantly with increasing number of days in culture. On day 3, basal PG release had decreased to half of that on day 1 of culture. However, both cell types were still able to respond to the addition of exogenous arachidonic acid (5 microM) on day 3 of culture, with PG release by GEC being elevated 7- to 10-fold and by STC moderately, but still significantly, on day 4. The permissive effect of arachidonic acid on the stimulation of PG release may indicate the down-regulation of phospholipase A2 with continued time in culture. However, the addition of arachidonic acid (5 microM) on day 0 of culture, while able to cause significantly increased PG release from GEC, had no effect on STC. In contrast, the addition of a combination of arachidonic acid (5 microM), and either recombinant human TNF-alpha (10 micrograms rhTNF-alpha/l) or 10 micrograms rhIL-1 alpha/l, had a synergistic action and caused the significantly increased release of PGF and PGE from both cell types, compared with that achieved with either arachidonic acid or the cytokine alone (although GEC responded more than STC). During the first 24 h after the addition of rhTNF-alpha or rhIL-1 alpha, both cytokines stimulated PG release from both cell types in a dose- and time-dependent fashion. Neither cycloheximide (10 microM) nor actinomycin D (10 microM) affected basal PG release, but both blocked cytokine-induced PG release from both cell types. These results suggest that there is a differential control of human endometrial cell PG biosynthesis, and that PG release may be regulated through gene activation.

Interleukin-1 alpha in the rabbit uterus during early pregnancy.

Immunoreactive (ir) interleukin-1 alpha (IL-alpha) was present in the endometrium and myometrium of the rabbit uterus during early pregnancy. Interleukin-1 alpha was at a high level in endometrial epithelium from days 3 to 6 of pregnancy. A similar level of IL-1 alpha was detected on day 6 of pseudopregnancy. Interleukin-1 alpha declined rapidly on day 7 at both the implantation and non-implantation areas. Our results suggest that IL-1 alpha may play a role in rabbit blastocyst implantation.

Investigation of alternate droplet material bubble dosimeters.

Past theoretical research involving superheated liquid droplet (bubble) neutron dosimeters has shown the possibility of using alternate droplet materials in order to give the dosimeter improved temperature stability. Based on that research testing was conducted on HFC-134a, propylene, propane, and hexafluoropropylene to determine (1) the compatibility of the novel superheated liquid material with the detector gel matrix material; (2) the gamma sensitivity of the detector droplets; (3) the response of the dosimeters as a function of neutron energy; and (4) the response of the dosimeters as a function of temperature. These tests were conducted at the Armed Forces Radiobiology Research Institute using a 60Co source, the Naval Surface Warfare Center using a tandem neutron accelerator, and the United States Naval Academy using an unmoderated 252Cf source. The response of the alternate droplet material dosimeters was compared to the response of the original Freon 12 droplet material dosimeter. The data indicated that the propane and propylene materials were chemically incompatible with the gel material and that the hexafluoropropylene dosimeters were sensitive to gamma radiation, thus making these types of dosimeters unsuitable. However, the HFC-134a superheated liquid droplets were stable in the gel material, responded uniformly over varying neutron energies, and had a predictable temperature response.

Leukaemia inhibitory factor in human endometrium during the menstrual cycle: cellular origin and action on production of glandular epithelial cell prostaglandin in vitro.

Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine which plays an obligatory role in mouse implantation. To investigate its potential role in the regulation of uterine function in the human, LIF secretion by isolated human endometrial glandular epithelial and stromal cells in primary culture was determined. Endometrial cells secreted a detectable amount of LIF protein during the first 48 h of culture. In the follicular and late-luteal phases, LIF secretion by both cell types was low. At every stage of the menstrual cycle, the epithelial cells secreted significantly more LIF than did stromal cells. Glandular epithelial cells of the mid-luteal phase, at the expected time of implantation in the human, secreted significantly more LIF than at other stages of the cycle. Stromal cells showed a similar, but nonsignificant, LIF secretion pattern. It could be concluded that endometrial LIF expression was dependent on cell type and stage of the menstrual cycle, and might thus play a role in human implantation. Oestradiol-17 beta stimulated both prostaglandin (PG) F and E release by the epithelial cells in both follicular and luteal phases. PGE release during the luteal phase was greater than in the follicular phase. However, addition of recombinant human LIF did not change either PGF or PGE release in either follicular or luteal phases, in the presence or absence of oestradiol.

Lyso-PAF:acetyl-CoA acetyltransferase and CDP-choline cholinephosphotransferase activities in the rabbit endometrium.

Endometrial platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine) levels change significantly during the pre-implantation period in the rabbit uterus, but under in vitro culture conditions, constitutive PAF biosynthesis by isolated endometrial tissues is not easily demonstrable. Rapid metabolism of PAF relative to its synthesis may account for this disparity because we have recently shown that in stromal cells there is a significant build-up of lyso-PAF suggesting that lyso-PAF-acetyl-CoA acetyltransferase might be a limiting factor. In the glandular epithelial cells however, the lyso-PAF build-up was replaced by a significant accumulation of a neutral lipid which was tentatively identified as 1-O-hexadecyl-2-acetylglycerol. It was hypothesized that, during endometrial growth and development, this lipid might serve as the substrate for the alkylacetylglycerol CDP-choline cholinephosphotransferase enzyme for PAF synthesis via the de novo pathway. We have therefore examined the activities of lyso-PAF:acetyl-CoA acetyltransferase and the CDP-cholinephosphotransferase enzymes. Microsomal preparations containing lyso-PAF:acetyl-CoA acetyltransferase activity catalyzed the incorporation of [3H]acetyl-CoA lyso-PAF into two distinct lipid products. One co-migrated with authentic PAF and the other with 1-O-hexadecyl-2-acetylglycerol, the latter being formed subsequent to PAF formation. The alkylacetylglycerol CDP-choline cholinephosphotransferase enzyme, which would potentially utilize the alkylacetylglycerol synthesized via the remodeling pathway, was also demonstrable. Unlike the species present in other tissues however, it was found to be sensitive to the presence of 10 mM DTT. The diacylglycerol CDP-choline cholinephosphotransferase species was also demonstrable and supported the synthesis of both PAF and phosphatidylcholine, in the absence of DTT, when only the synthesis of phosphatidylcholine was expected. It is hypothesized that the rabbit endometrium possesses active enzymes which may catalyze PAF synthesis via both the de novo and 'remodeling' pathways.

Expression patterns of leukaemia inhibitory factor receptor (LIFR) and the gp130 receptor component in rabbit uterus during early pregnancy.

The presence of leukaemia inhibitory factor (LIF) binding and expression of the gp130 component of the LIF receptor were studied in the rabbit uterus during pregnancy. LIF binding to myometrium was moderate in oestrous and non-oestrous animals and on day 1 of pregnancy, declined on days 2 and 3, and increased to a peak value on days 5 and 6 of pregnancy. Binding to stromal cells was not observed. Binding of LIF to luminal and glandular epithelium was low in unmated animals and on days 1 and 2 of pregnancy. Binding to luminal epithelium increased from day 3, and to glandular epithelium from day 5 of pregnancy. Highest binding was seen on days 5 and 6, with a slight decline observed on day 7, and with little difference between the mesometrial and antimesometrial regions of the implantation site. In all cases, binding of LIF was similar in the uteri of day 6 pseudopregnant and pregnant animals. At all stages, gp130 was absent from stroma and almost absent from myometrium and glandular epithelium. It was expressed in luminal epithelium, reaching maximal expression on day 6 of pregnancy and pseudopregnancy, but diminished on day 7 of pregnancy, particularly in the antimesometrial area of the implantation site. The coexpression of LIF binding and gp130 may indicate the presence of high-affinity LIF receptor, which matches the pattern of LIF protein expression and, as in mice, suggests its importance for implantation.

Temporal and spatial expression of leukemia inhibitory factor in rabbit uterus during early pregnancy.

Leukemia inhibitory factor (LIF) has been shown to play an important role in the implantation of mouse blastocysts. The present study was designed to document the appearance of LIF in the rabbit uterus during early pregnancy and to determine whether changes just prior to implantation, similar to those in mice, occurred. LIF was localized in endometrial epithelium, myometrium, and endometrial glands. A low level of LIF was detected in the uterus of nonestrous and estrous females. LIF expression reached its highest level on day 5 of pregnancy and declined on days 6 and 7. By day 13 of pregnancy, little endometrial LIF was apparent. The expression of LIF on day 5 of pseudopregnancy was similar to that on day 5 of pregnancy. LIF expression was much higher at implantation sites than that at nonimplantation areas on day 7 of pregnancy. It is concluded that LIF may be important for the implantation of rabbit blastocysts.

Platelet-activating factor antagonists and implantation in rabbits.

In an initial experiment, rabbits were injected i.v. with a platelet-activating factor (PAF) antagonist CV-3988 twice a day on days 5 and 6 of pregnancy. Some inhibition of implantation was observed. This effect could not be reproduced in subsequent experiments at the same or at larger or smaller doses. The non-metabolized analogue of PAF, N-carbamyl-PAF (C-PAF) had an inhibitory effect on implantation only when given at toxic concentrations. When CV-3988 and C-PAF were given together on days 5 and 6, there was no effect on implantation. None of the other PAF antagonists tested--BN52021, SRI63,441, WEB2086 or TCV-309--at various doses could inhibit implantation when given on the same days of pregnancy. TCV-309, at 0.1 mg kg-1 i.v. given on days 2-4 of pregnancy, was also ineffective. These results provide no clear support for a role of PAF in implantation in rabbits.

Pregnancy-associated remodeling of rabbit endometrial platelet-activating factor receptors.

[3H]PAF binding parameters (affinity constants and binding capacities) were estimated for endometrial membranes obtained on days 3 (when the morulae first enter the gravid uterus), 4, 5 and on day 6, about 22 h before the blastocyst becomes irremovably attached to the endometrium. The two-site receptor system which characterized the binding on a large proportion of purified membranes from days 3 (60%) and 6 (75%) had the following parameters: day 3, Kd1 (nM) 0.15 +/- 0.04, Bmax1 (pmol/mg protein) 0.04 +/- 0.01; Kd2 (nM) 17.60 +/- 6.40, Bmax2 (pmol/mg protein) 2.92 +/- 0.91 (n = 6), and day 6, Kd1 (nM) 0.33 +/- 0.06, Bmax1 (pmol/mg protein) 0.11 +/- 0.02; Kd2 (nM) 7.42 +/- 1.02, Bmax2 (pmol/mg protein) 1.75 +/- 0.31 (n = 3). The remaining membranes, including all preparations of days 4 and 5, exhibited only one class of binding sites which were unlike the putative type 1 PAF receptor. The most significant observations were the apparent pregnancy-associated changes in the parameters of the PAF binding sites. However, regardless of the type of PAF binding exhibited, all the binding sites bound GTP. [3H]PAF dissociation from bound complexes was biphasic at 25 degrees C. The rate constants were k-1, 0.27 +/- 0.09 min-1 and k-2, 3.45 +/- 1.19 x 10(-3) min-1, for the rapid and slow dissociating components, respectively. In view of the inability to resolve the experimental data from days 4 and 5 into multiple sites, and of the occurrence of receptor interconversions on days 3 and 6, it is postulated that there may be cell membrane macromolecular reorganization/remodeling of proteins and cytoskeleton as a result of the arrival of blastocyst in the uterus and/or the dynamic interplay of local uterine PAF and the hormonal milieux during the peri-implantation period of pregnancy.