Significant Blocking Effect Research Articles

Design, synthesis and biological evaluation of novel amino acid ureido derivatives as aminopeptidase N/CD13 inhibitors

A series of amino acid ureido derivatives as aminopeptidase N (APN/CD13) inhibitors were synthesized and evaluated for their APN inhibitory activities and anti-cancer effects. The results showed that most of these amino acid ureido derivatives exhibited good inhibition against APN, several of which were better than Bestatin. The most active compound 12j (IC50=1.1μM, compared with Bestatin IC50=8.1μM) not only possessed much better APN inhibitory activity and anti-proliferation effect on cancer cells, but also exhibited significant block effect of human cancer cell invasion compared with the positive control, Bestatin. These amino acid ureido derivatives could be possibly developed as new APN inhibitors for cancer chemotherapy in the future.

Effects of supermagnetic iron oxide labeling on the major functional properties of human mesenchymal stem cells from multiple sclerosis patients.

In the last few years, treatment protocols using mesenchymal stem cells (MSC) in various experimental models and human diseases have been investigated. MSCs are on the focus of stem cell research, since they are considered as a type of adult stem cells with low toxicity and acceptable side effects profile and they can be administered autologously. In addition several studies have revealed significant immunomodulatory properties of MSCs and a potential for transdifferentiation, including neural differentiation, both in vivo and in vitro. Magnetic resonance imaging (MRI) is a non-invasive technique that can be used to track labeled cells and evaluate their migration ability in various clinical settings. In this study we investigated whether such labeling of MSCs with the commercially used para-magnetic material, Feridex, has any negative effect on the above mentioned functional properties of MSCs. We labeled human mesenchymal stem cells (hMSC) with poly-L-lysine coated Feridex(®) and evaluated their cellular differentiation and immunomodulatory properties, in vitro. In comparison with unlabeled cells, labeled hMSC exhibited normal adipogenic and osteogenic differentiation, but decreased chondrogenic differentiation. Regarding neural differentiation, labeled and unlabeled cells were similar in their ability to express neural-like and glial like surface proteins. Finally, both labeled and unlabeled MSCs exhibited a dose-dependent, significant blocking effect on the proliferation of healthy donors lymphocytes following mitogen stimulation. These findings indicate that labeling with Feridex does not affect the immunomodulatory, nor the neural transdifferentiation potential of MScs and therefore, Feridex may be used for the tracking of this type of stem cells in clinical applications, without compromising their major functional properties.

ATP-induced Ca2+ waves in the nucleus accumbens

Event Abstract Back to Event ATP-induced Ca2+ waves in the nucleus accumbens Tünde Molnár1*, Gabriella Nyitrai1, Péter Barabás1, Julianna Kardos1 and Miklós Palkovits2 1 Chemical Research Center, Hungarian Academy of Sciences, Department of Neurochemistry, Institute of Biomolecular Chemistry, Hungary 2 Semmelweis University and Hungarian Academy of Sciences, Neuromorphological and Neuroendocrine Research Laboratory, Hungary We have previously described a membrane target in subfractions of the nucleus accumbens (NAcc) that binds metabolites succinic acid (SUC) and gamma-hydroxybutyric acid (GHB), as well as the gap-junction blocker carbenoxolone (CBX). In the present study, we investigated the acute effect of SUC, GHB and CBX on propagating Ca2+ waves induced by extracellular ATP (100 μM) in NAcc slices loaded by the fluorescent intracellular Ca2+ indicator Fluo-4 AM. Confocal laser scanning microscopy has been used to detect changes in numbers and the fluorescence intensity of cells participating in the Ca2+ wave. We suggest, that ATP-induced Ca2+ wave propagates in astrocytes located in the NAcc, which can be significantly decreased by gap-junction blockers CBX (0.1 and 1 mM) and flufenamic acid (FFA 1 mM). Conversely, the non-selective P2 purinergic antagonist suramin (0.1 and 1 mM) had no significant blocking effect on the number and the fluorescence intensity of cells of ATP-induced Ca2+ waves in the NAcc, suggesting that such propagation depends mainly on the functional activity of gap-junctions. The effects of SUC and GHB were found as concentration-dependent. In low concentration (0.05 mM) SUC and GHB enhanced both the number and the fluorescence intensity of cells, while their applications in higher concentrations (0.2 and 2 mM) elicited an inhibitory effect of SUC. In addition, whole cell patch clamp recordings of tetrasodium Fluo-4 loaded NAcc medium spiny neurons showed no changes in electrical activity and intracellular Ca2+ level during the propagation of ATP-induced astrocytic Ca2+ wave. Our findings indicate that calcium waves propagate by a mechanism involving gap-junction mediated interactions between astrocytes in the Nacc. The facilitatory role in astrocytic Ca2+ wave propagation suggests that SUC may represent a strong candidate for metabolic signalling, and therefore, a benefit for further studies. Conference: IBRO International Workshop 2010, Pécs, Hungary, 21 Jan - 23 Jan, 2010. Presentation Type: Poster Presentation Topic: Cellular neuroscience Citation: Molnár T, Nyitrai G, Barabás P, Kardos J and Palkovits M (2010). ATP-induced Ca2+ waves in the nucleus accumbens. Front. Neurosci. Conference Abstract: IBRO International Workshop 2010. doi: 10.3389/conf.fnins.2010.10.00096 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Apr 2010; Published Online: 22 Apr 2010. * Correspondence: Tünde Molnár, Chemical Research Center, Hungarian Academy of Sciences, Department of Neurochemistry, Institute of Biomolecular Chemistry, Budapest, Hungary, tmolnar@chemres.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Tünde Molnár Gabriella Nyitrai Péter Barabás Julianna Kardos Miklós Palkovits Google Tünde Molnár Gabriella Nyitrai Péter Barabás Julianna Kardos Miklós Palkovits Google Scholar Tünde Molnár Gabriella Nyitrai Péter Barabás Julianna Kardos Miklós Palkovits PubMed Tünde Molnár Gabriella Nyitrai Péter Barabás Julianna Kardos Miklós Palkovits Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Flow Activation of AMP-Activated Protein Kinase in Vascular Endothelium Leads to Krüppel-Like Factor 2 Expression

Vascular endothelial cells (ECs) confer atheroprotection at locations of the arterial tree where pulsatile laminar flow (PS) exists with a high shear stress and a large net forward direction. We investigated whether the PS-induced expression of the transcription factor Krüppel-Like Factor 2 (KLF2) in cultured ECs and its expression in the mouse aorta is regulated by AMP-activated protein kinase (AMPK). AMPK inhibition by Compound C or siRNA had a significant blocking effect on the PS-induced KLF2 expression. The induction of KLF2 by PS led to the increase in eNOS and the suppression of ET-1, which could be reversed by KLF2 siRNA. In addition, PS induced the phosphorylation of ERK5 and MEF2 which are necessary for the KLF2 expression. These mechanotransduction events were abrogated by the blockade of AMPK. Furthermore, the phosphorylation levels of ERK5 and MEF2, as well as the expression of KLF2, were significantly reduced in the aorta of AMPKalpha2 knockout mice when compared with wild-type control mice. The flow-mediated AMPK activation is a newly defined KLF2 regulatory pathway in vascular endothelium that acts via ERK5/MEF2.

Effects Of Acute Whole Body Vibration On Fatigue During Leg Press Exercise Session

Introduction: Often these athletes experience fatigue in between sets and this fatigue leads to poor biomechanics and lesser gains in strength. Whole-body vibration (WBV) training has been used to improve strength and vertical jump height in various athletes. Several studies had suggested an increase in sports performance after whole-body vibration training program either acutely or chronically. However, is of our knowledge that little data exists on the effects of WBV training on mechanisms of fatigue during muscular strength activities. PURPOSE: To examine whether implantation of WBV during normal rest periods affects the fatigue associated with resistance exercise by measures of power, force, velocity and the force-velocity curve during a series of dynamic leg presses until failure. METHODS: Ten sedentary college students (N = 5 males, 19 + 1.3 yrs), and N = 5 females, 19,+0.5 yrs) participated in three trial sessions of 3 sets of dynamic leg press exercise to failure with 3.5 min rest in between sets. Subjects on the WBV trial were exposed to 60 sec vibration and 30 sec rest during their 3.5 min rest. Control subjects were stationary between sets and rest intervals. Statistical analyses utilized a two-way ANOVA with repeated measures for power, force, velocity, and force-velocity curves. RESULTS: No significant differences (p > 0.05) were observed for the dependent variables power, force, velocity and force-velocity curve between WBV and CON groups. However, a significant block effect (p > 0.05) as well as a significant test × block interaction (p > 0.05) was observed. The second block in each set of three blocks/test has the greatest power. CONCLUSIONS: Acute WBV exposure in between sets had no effects on fatigue during leg press exercise as indicated by the measures power, force, velocity and force-velocity curve. The force/velocity curve shows that little resistance at a high velocity will not produce the greatest power, and high force at a slower resistance will not elicit the highest power either.

Watermarking in conjugate ordered dither block truncation coding images

In this work, a novel method based on block truncation coding (BTC) and halftoning technique is proposed for embedding watermarks into compressed images. BTC is a simple and efficient image compression technique. However, it yields images of unacceptable quality and significant blocking effects are seen when the block size used increases. A modified technique known as order dither block truncation coding (ODBTC) is proposed to solve the above problems while maintaining the same compression capability. In addition, ODBTC can also be used to embed a watermark into the compressed image. This technique incorporates void-and-cluster method with BTC and ordered dithering to carry out watermarking. Experimental results have indicated that the resulting image quality is better and the algorithm less complex as than traditional BTC. Many forms of attacks are also carried out and confirm the robustness of the proposed methods.

Traditional AMPA receptor antagonists partially block Na v1.6-mediated persistent current

Voltage-gated Na channels and AMPA receptors play key roles in neuronal physiology. Moreover, both channels have been implicated in the pathophysiology of both grey and white matter in a variety of conditions. Dissecting out the roles of these channels requires specific pharmacological tools. In this study we examined the potential non-specific effects on Na v1.6 channels of five widely used AMPA receptor blockers. Using whole-cell patch clamp electrophysiology, we identified a TTX-sensitive persistent Na channel current in HEK cells stably expressing the Na v1.6 channel. From a holding potential of −120 mV, slow ramp depolarization to +75 mV generated an inward current that peaked at approximately −15 mV. Superfusion of purportedly specific AMPA antagonists, 1-naphthylacetyl spermine, SYM2206, CP465022, GYKI52466, blocked Na v1.6-mediated persistent currents in a dose-dependent manner. Each of these AMPA receptor blockers significantly inhibited (to ≈70% of control levels) the persistent Na current at concentrations routinely used to selectively block AMPA receptors. The AMPA/kainate blocker, NBQX, did not significantly affect persistent Na channel currents. Furthermore, peak transient current was insensitive to NBQX, but was reversibly inhibited by SYM2206, CP465022 and GYKI52466. These results indicate that many commonly used AMPA receptor antagonists have modest but significant blocking effects on the persistent components of Na v1.6 channel activity; therefore caution should be exercised when ascribing actions to AMPA receptors based on use of these inhibitors.

Experimental assessment of trophic impacts from a network model of a seagrass ecosystem: Direct and indirect effects of gulf flounder, spot and pinfish on benthic polychaetes

Trophic cascades are predicted to occur when the abundance of predators is increased, directly reducing the abundance of the intermediate prey and indirectly increasing the abundance of the prey at the base of a food web. Mixed trophic impact analysis of a network model developed for Apalachee Bay, near St. Marks, FL, USA predicted such a trophic cascade, in that increased abundance of juvenile gulf flounder Paralichthys albigutta ( x¯ = 149 mm SL, effective trophic level 3.9) should have a negative impact on juvenile spot Leiostomus xanthurus ( x¯ = 30 mm SL, effective trophic level 2.9) and a positive impact on benthic polychaetes (effective trophic levels 2.3 for deposit feeders and 3.0 for predatory polychaetes) in Halodule wrightii seagrass beds. We tested the predictions of the mixed trophic impact analysis by manipulating the abundance of the high trophic-level species (juvenile gulf flounder) in a cage-exclusion study in the North River, near Harkers Island, NC, USA. We compared the polychaete communities in St. Marks, FL and Harkers Island, NC, and showed that they are 51% similar (Jaccard's Index) at the family level, with the same eight dominant families (Nereidae, Capitellidae, Syllidae, Spionidae, Cirratulidae, Terebellidae, Sabellidae, and Maldanidae) present in both locations. We used 24 open-bottom cages to enclose the benthos and its seagrass-associated animal communities. We manipulated each cage by assigning it to one of the following treatments: (1) inclusion of fishes in upper and intermediate trophic levels (1 juvenile gulf flounder and 10 juvenile spot, the flounder + spot treatment); (2) inclusion of the intermediate predator (10 juvenile spot with no gulf flounder, the spot-only treatment); and (3) no fish added (unmanipulated controls). Core samples taken within the cages provided pre- and post-experimental measures of polychaete density and biomass, and the difference in density and biomass were used as response variables. At the end of the experiment, we collected, weighed, and analyzed the gut contents of all juvenile spot present in the cages. Juvenile pinfish ( Lagodon rhomboides, x¯ = 30 mm SL) were present at the end of the study, having arrived as larvae or being trapped during cage set-up, and these fish were also examined, because they also eat polychaetes and their natural densities exceeded our introduced spot densities. Significant differences among treatments were detected for the polychaete family Terebellidae for both the change in density and biomass (pre-experiment − post-experiment). Densities of the Terebellidae changed in the direction predicted by the network model's impact analysis, declining in the cages with spot added compared with the control cages. Analyses of the other response variables (post-experiment spot and pinfish densities and biomass, difference between pre- and post-experiment polychaete densities and biomass for other families, and post-experiment spot and pinfish stomach content biomass) showed no significant differences among treatments. Several variables (Nereidae densities, pinfish densities and biomass, and pinfish stomach content biomass) varied between cages with low and high seagrass cover (significant blocking effect, P < 0.001). Nereidae densities declined significantly in cages with high (73%) rather than with low coverage (31% cover) of seagrass. Pinfish density and biomass were significantly greater in the high seagrass cages at the end of the experiments ( P < 0.001), suggesting that dense seagrass attracted them. We conclude that the high density of pinfish in dense seagrass was responsible for the decline in density of the Nereidae. The direct effect of intermediate predators (pinfish feeding on polychaete prey) can be influenced by preferential recruitment of fishes to structurally complex habitats. The direction of change of indirect effects, but not the magnitude, in multi-trophic-level food webs can be predicted by the mixed trophic impact analysis of network models. However, these indirect effects are likely to be small in magnitude relative to direct effects and may be difficult to detect experimentally, especially in low-power experimental caging studies with natural fluctuations in recruitment rates of competitor species.

Replicability of physicochemistry and macroinvertebrate assemblages in stream mesocosms: implications for experimental research

Summary1. The replicability of mesocosms is assessed in a case study of artificial streams (4 m2) flanking a lowland chalk river in southern U.K. Among‐mesocosm comparisons of physicochemistry and macroinvertebrate assemblage composition (in drift and benthos) were made during a 2‐year survey of 12 outdoor once‐through linear channels.2. Mesocosm physicochemistry was highly replicable, with statistically significant congruence in temporal variation across the mesocosm series, low spatial variation and no significant blocking or positional effects arising from mesocosm layout. Parallel physicochemistry was attributed to the outdoor stream‐side location and short water residence times.3. Mesocosms were colonized by 127 macroinvertebrate taxa from 15 taxonomic orders. Both benthic and drifting assemblages were comparable among mesocosms, with no significant effect of mesocosm layout. Small differences in taxonomic composition were, however, evident among particular mesocosms, with higher (e.g. Tinodes, Limnius and Elmis) or lower (e.g. Pisidium and Valvata) abundances observed for a minority (5%) of taxa. We conclude that large (4 m2) outdoor flow – through mesocosms can be replicable when located near to the source system and allowed to establish naturally.

Detection of antizona pellucida antibodies in the sera from premature ovarian failure patients by a highly specific test

To develop a highly specific test for the detection of antizona pellucida (ZP) antibodies in the sera from premature ovarian failure (POF) patients. Laboratory study. University hospital. Twenty-seven idiopathic POF patients, 30 control women, and 30 healthy males. Anti-ZP antibodies were detected by the microdot assay using a very small amount of human ZP or porcine ZP. The effect of anti-ZP antibodies on sperm-ZP binding was examined by hemizona assay. Results from the microdot assay and hemizona assay. By the microdot assay using human ZP, the sera from POF patients reacted significantly stronger than those of control women and healthy males. However, no obvious difference could be found by the same assay using porcine ZP among these three groups. Anti-ZP antibodies against sera from some POF patients showed significant blocking effects on sperm-ZP binding assessed by hemizona assay. Anti-ZP antibodies were detected in 7 of 27 POF patients, while none were detected in control women and healthy males. Some idiopathic POF patients have anti-ZP antibodies in their sera, which were detected with high specificity by a newly developed microdot assay using a very small amount of human ZP.

GROWTH AND FRUITING CHARACTERISTICS OF EIGHT APPLE GENOTYPES ASSESSED AS UNPRUNED TREES ON 'M.9' ROOTSTOCK AND AS OWN-ROOTED TREES IN SOUTHERN FRANCE

ISHS VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems GROWTH AND FRUITING CHARACTERISTICS OF EIGHT APPLE GENOTYPES ASSESSED AS UNPRUNED TREES ON 'M.9' ROOTSTOCK AND AS OWN-ROOTED TREES IN SOUTHERN FRANCE

Evaluation of [ 11C]hemicholinium-15 and [ 18F]hemicholinium-15 as new potential PET tracers for the high-affinity choline uptake system in the heart

[ 11C]Hemicholinium-15 ([ 11C]HC-15) and [ 18F]hemicholinium-15 ([ 18F]HC-15) have been synthesized as new potential PET tracers for the heart high-affinity choline uptake (HACU) system. [ 11C]HC-15 was prepared by N-[ 11C]methylation of the appropriate precursor, 4-methyl-2-phenyl-morpholin-2-ol, using [ 11C]CH 3OTf in 55–70% radiochemical yield decay corrected to end of bombardment (EOB) and 2–3 Ci/μmol specific activity at end of synthesis (EOS). [ 18F]HC-15 was prepared by N-[ 18F]fluoromethylation of the precursor using [ 18F]FCH 2OTf in 20–30% radiochemical yield decay corrected to EOB and >1.0 Ci/μmol specific activity at EOS. The biodistribution of both compounds was determined in rats at 20 min post-intravenous injection, and the results show the heart region uptakes 1.32 ± 0.75%ID/g in R-ventricle for [ 11C]HC-15 and 1.28 ± 0.81%ID/g in L-ventricle for [ 18F]HC-15, respectively. The dynamic PET imaging studies of [ 11C]HC-15 in rats were acquired 60 min post-intravenous injection of the tracer using the IndyPET-II scanner. For the blocking experiments, the rats were intravenously pretreated with 3.0 mg/kg of unlabeled HC-15 prior to [ 11C]HC-15 injection. [ 11C]HC-15 rat heart PET studies show rapid heart uptake to give clear heart images. The rat heart PET blocking studies found no significant blocking effect. The dynamic PET studies in normal and ablated dogs were performed using Siemens PET scanner with [ 13N]NH 3, [ 11C]HC-15, and [ 18F]HC-15. PET studies in dogs of both [ 11C]HC-15 and [ 18F]HC-15 also show significant heart uptake and give images of the heart. However, there is no significant change in [ 11C]HC-15 L-ventricle uptake following radiofrequency ablation in the dog. These results suggest that the localization of HC-15 tracers in the heart is mediated by non-specific processes, and the visualization of HC-15 tracers on the heart is related to non-specific binding of HACU.

Endostatin binds biglycan and LDL and interferes with LDL retention to the subendothelial matrix during atherosclerosis

Retention of lipoproteins to proteoglycans in the subendothelial matrix (SEM) is an early event in atherosclerosis. We recently reported that collagen XVIII and its proteolytically released fragment endostatin (ES) are differentially depleted in blood vessels affected by atherosclerosis. Loss of collagen XVIII/ES in atherosclerosis-prone mice enhanced plaque neovascularization and increased the vascular permeability to lipids by distinct mechanisms. Impaired endothelial barrier function increased the influx of lipoproteins across the endothelium; however, we hypothesized that enhanced retention might be a second mechanism leading to the increased lipid content in atheromas lacking collagen XVIII. We now demonstrate a novel property of ES that binds both the matrix proteoglycan biglycan and LDL and interferes with LDL retention to biglycan and to SEM. A peptide encompassing the alpha coil in the ES crystal structure mediates the major blocking effect of ES on LDL retention. ES inhibits the macrophage uptake of biglycan-associated LDL indirectly by interfering with LDL retention to biglycan, but it has no direct effect on the macrophage uptake of native or modified lipoproteins. Thus, loss of ES in advanced atheromas enhances lipoprotein retention in SEM. Our data reveal a third protective role of this vascular basement membrane component during atherosclerosis.

Influence of seminal plasma PSP-I/PSP-II spermadhesin on pig gamete interaction

The seminal plasma PSP-I/PSP-II spermadhesin is able to preserve, in vitro, the viability of highly extended boar spermatozoa, suggesting it might be used as a suitable ameliorator for the damaging effects of sperm handling, including in vitro fertilization. However, little is known about the ligand capability of PSP-I/PSP-II as regards the zona pellucida (ZP) or its possible role in gamete interaction. The present study evaluated the effect of the presence of PSP-I/PSP-II (1.5 mg/ml) during in vitro oocyte maturation and also during co-incubation of frozen-thawed boar spermatozoa with either immature (IM) or in vitro matured (IVM) oocytes, either enclosed by cumulus cells or denuded. Exposure of the gametes to the heterodimer during in vitro gamete co-incubation showed a significant blocking effect of sperm penetration rates and a decreased number of spermatozoa per oocyte in both IM and IVM denuded oocytes. Such an effect was not present in cumulus-enclosed oocytes, suggesting the effect could be mediated by exposed ZP receptors. In addition, when PSP-I/PSP-II was added to the IVM medium, oocyte maturation rates were significantly reduced. In conclusion, the results suggest that PSP-I/PSP-II, when present in vitro, blocks sperm-ZP binding.

Bacterial protein grown on natural gas as protein source in diets for Atlantic salmon, Salmo salar, in saltwater

Bacterial protein meal (BPM) produced on natural gas was evaluated with respect to growth, nutrient digestibilities, feed conversion ratios, sensory quality, and histopathological indices in Atlantic salmon in saltwater. In the extruded diets, experimentally produced BPM accounted for 0, 10, or 20% of the ingredients or 0, 17.2, or 33.1% of dietary nitrogen, replacing high-quality fish meal. Each diet was fed to two groups of salmon with a mean initial weight of 1.4 kg for 5 months. The pens were organized in two randomized blocks. One block was located with one side of the pens exposed to the open sea. The other block was completely surrounded by other pens. During the experiment, the salmon increased to approximately 3.6–3.9 kg in weight. Analysis of variance revealed no significant ( P>0.05) differences in growth, but regression analysis showed that fish weights at 2 and 5 months and growth rates for the whole experiment were slightly reduced with increasing content of BPM. No significant effects of diet were seen on dressed-out carcass, liver, or intestine to body weight percentages. Carcass and visceral fat and dry matter contents decreased with increasing dietary BPM. There was a trend (0.10≤ P<0.05) that apparent digestibilities of nitrogen, fat, and energy were reduced when substituting fish meal with BPM, while the nitrogen retention was not significantly affected. Flesh carotenoid concentration and colour were not significantly affected by dietary composition, nor were any differences seen for sensory characteristics related to taste, smell or texture. Histological examination did not reveal abnormalities, or signs of allergic reaction against BPM components, and hematocrit values were within normal ranges. Significant block effects were seen for chemical composition of viscera, and digestibilities of nitrogen, fat, and energy.

Does seminal plasma PSP-I/PSP-II spermadhesin modulate the ability of boar spermatozoa to penetrate homologous oocytes in vitro?

Low concentration (0.15 mg per million of spermatozoa) of seminal plasma-derived PSP-I/PSP-II spermadhesin heterodimer is able to preserve the viability of highly extended boar spermatozoa. Whether spermatozoa also keep their fertilizing capacity is not yet known. The present study evaluated the effect of exposing freshly extended and frozen-thawed boar spermatozoa (10 million/mL) to PSP-I/PSP-II (1.5 mg/mL) for 30 or 120 minutes on sperm characteristics and the outcome of in vitro penetration of immature (IM) and in vitro matured (IVM) homologous oocytes, aiming to identify this spermadhesin as a suitable modulator for sperm-handling protocols. Although exposure to the heterodimer improved sperm viability and motility without increasing the levels of sperm acrosome exocytosis in both freshly extended and frozen-thawed spermatozoa, this pretreatment did not affect sperm penetration rates or sperm numbers per oocyte when pretreated fresh spermatozoa were coincubated with IM or IVM oocytes compared with controls. When cryopreserved spermatozoa were tested, however, on IVM oocytes, already a 30-minute preincubation exposure to PSP-I/PSP-II showed a significant blocking effect on penetration rate (from 90% to 32%, P < .05) and on mean sperm numbers per oocyte (2.9 to 1.6, P < .05). To disclose the nature of this paradox, frozen-thawed spermatozoa were cleansed (by centrifugation in saline bovine serum albumin or through Percoll density gradient separation) and the procedure repeated. Oocyte penetration (but not number of spermatozoa per oocyte) increased (P < .05) when spermatozoa were cleansed with Percoll compared with either washed or unwashed controls (53% vs 13% vs 31%, respectively). In addition, the percentages of polyspermic oocytes remained lower than control (38.5% vs 68.7%, respectively; P < .05). In conclusion, the results confirm that exposure of fresh or frozen-thawed boar spermatozoa to a low dose of seminal PSP-I/PSP-II spermadhesin preserves sperm viability and motility in vitro. Although there was no obvious influence of the heterodimer on the capability of freshly extended boar spermatozoa to penetrate homologous oocytes (either IM or IVM), PSP-I/PSP-II exerted a deleterious effect when frozen-thawed spermatozoa were used to penetrate IVM oocytes. Such an effect of cryopreservation seems to a certain extent reversible, since cleansing of the sperm surface decreased, at least partially, this blocking effect, increasing both penetration and the monospermic rates.

Experimental study of anti-tumor effects of polysaccharides from Angelica sinensis.

To investigate the in vivo anti-tumor effects of total polysaccharide (AP-0) isolated from Angelica sinensis (Oliv.) Diels (Danggui) on mice and the in vitro inhibitory effects of AP-0 and the sub-constituents (AP-1, AP-2 and AP-3) separated from AP-0 on invasion and metastasis of human hepatocellular carcinoma. Three kinds of murine tumor models in vivo, sarcoma 180 (S180), leukemia L1210 and Ehrlich ascitic cancer (EAC) were employed to investigate the anti-tumor effects of AP-0. For each kind of tumor model, three experimental groups were respectively given AP-0 at doses of 30, 100 and 300 mg/kg by ip once a day for 10 days. Positive control groups were respectively given Cy at a dose of 30 mg/kg for S180 and leukemia L1210, and 5-FU at a dose of 20 mg/kg for EAC. On d 11, mice bearing S180 were sacrificed and the masses of tumors, spleens and thymus weighed. The average living days of mice bearing EAC and of mice bearing L1210 were observed, and the rates of life prolongation of each treatment were calculated, respectively. The inhibitory effects of APs on hepatoma invasion and metastasis in vitro were investigated by employing human hepatocellular carcinoma cell line (HHCC) with the Matrigel invasion chamber, adhesion to extracellular matrix and chemotatic migration tests, respectively. AP-0 had no obviously inhibitory effect on the growth of S180, but it could significantly decrease the thymus weights of the mice bearing S180. AP-0 could significantly reduce the production of ascitic liquids and prolong the life of mice bearing EAC. AP-0 could also increase the survival time of mice bearing L1210. AP-0 and AP-2 had significantly inhibitory effects on the invasion of HHCC into the Matrigel reconstituted basement membrane with the inhibitory rates of 56.4 % and 68.3 %, respectively. AP-0, AP-1, AP-2 and AP-3 could influence the adhesion of HHCC to extracellular matrix proteins (Matrigel and fibronectin) at different degrees, among them only AP-3 had significant blocking effect on the adhesion of HHCC to fibronectin with an inhibitory rate of 30.3 %. AP-0, AP-1 and AP-3 could partially inhibit the chemotactic migration abilities of HHCC. The experimental findings suggest that the total polysaccharide of Angelica sinensis (Oliv.) Diels (Chinese Danggui) possesses anti-tumor effects on experimental tumor models in vivo and inhibitory effects on invasion and metastasis of hepatocellular carcinoma cells in vitro.

Distribution, relative importance and effect of lepidopterous borers on maize yields in the forest zone and mid-altitude of Cameroon.

Geographic distribution, relative importance, and effect of lepidopterous stem and ear borers on maize, Zea mays L., were studied in the humid forest and the mid-altitude zones of Cameroon from 1994 to 1997. Six villages were chosen in the forest zone and grouped into three blocks representing gradients in human population density. A single block with three villages was chosen in the mid-altitude. Farmers' maize fields were surveyed during the vegetative growth phase for Busseola fusca (Fuller) egg batches, and at harvest for number of larvae and pupae by species, plant damage, and ear weight. There was no significant block effect for any of the variables measured, and most of the overall variance (72-99%) was attributed to within-field variability. In the forest zone, the noctuid B. fusca and the pyralid Eldana saccharina (Walker) accounted for >80% of all species in almost all locations, followed by the pyralid Mussidia nigrivenella (Ragonot) and the tortricid Cryptophlebia leucotreta (Meyrick). The noctuid Sesamia calamistis (Hampson) was found in almost all locations during the first season but disappeared in most locations in the second season. B. fusco egg infestation was significantly higher during the second compared with the first season, whereas larval and pupal densities were much higher during the first season. E. saccharina was the predominant species during the second season, when densities increased fourfold. In the mid-altitude, B. fusca was the predominant species. No significant differences in pest densities, plant damage, and ear weight were found between years. Results of stepwise regression of stem and ear damage on pest densities verified the relative importance of the individual species. In the forest zone, ear and stem damage significantly reduced ear weight, whereas in the mid-altitude only stem tunneling was significant.

Emergent patterns of feedback strategies in performing a closed motor skill.

This sturdy identified self-chosen patterns of feedback usage and how they influenced accuracy and consistency in performing a closed motor skill. Learners completed 100 practice trials with 25 opportunities to receive knowledge of results (KR), the timing of which was self-chosen, followed by 25 no KR retention trials. The study identified two patterns of self-chosen KR, namely, a faded frequency pattern and a reversed faded frequency pattern. Analyses of variance indicated a significant trial block effect for accuracy in acquisition and no significant main effects or interactions associated with self-chosen patterns of KR. Quantification of regularity of KR patterns yielded correlations indicating that less regularity was associated with greater accuracy in performing the task. These results were congruent with previous research on self chosen feedback.

Site switching and restructuring of oxygen adlayers induced by high coverage NO on Co{101̄0} at 100 K

We have employed reflection–absorption IR spectroscopy (RAIRS) as the principal technique as well as low energy electron diffraction (LEED) and temperature programmed desorption (TPD) as diagnostic tools to study the adsorption and reaction of nitric oxide (NO) on oxygen precovered Co{101̄0} surfaces at 100 K. The presence of oxygen adatoms greatly attenuates the occupation of two-fold sites in favor of atop sites, but O adatoms do not show any significant blocking effect for NO adsorption, and the NO coverage is close to 0.5 ML, as found on the clean surface. Beyond a critical coverage of NO, whatever the initial O coverage, a new IR band appears at ∼1876 cm−1 which is indicative of a strong NO–O interaction. The coadsorption of NO with various precoverages of oxygen (0.15–1.0 ML) including three ordered oxygen overlayers, c(2×4) (θO≈0.5 ML), p(2×1) (θO≈0.5 ML), and p(2×1)-g (θO≈1.0 ML), reveals an NO-induced surface restructuring process, in which O adatoms are driven from overlayer to underlayer sites at high NO coverages. This restructuring process increases the O effective diameter to up to ∼10 Å, this being the range over which the NO–O interaction is strong, producing the 1870 cm−1 N–O band.