bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gαs levels regulate Xenopus laevis oocyte maturation
Authors: Romo Ximena , Hinrichs M. Victoria , Guzmán Leonardo , Olate Juan 
Published: October 2002

AbstractProgesterone, produced by follicular cells, induces Xenopus laevis oocyte maturation through a very early event that inhibits the activity of the adenylyl cyclase effector system. The participation of a G‐protein has been implicated, based on the fact that the inhibitory effect of the steroid is GTP‐dependent, and it has been proposed that progesterone acts interfering with Gαs function at the plasma membrane. Here we investigate whether the change in oocyte Gαs levels affects the maturation process induced by progesterone. Overexpression of X. laevis wild type (wt) Gαs and the constitutive activated Gαs(QL) mutant, both blocked progesterone‐induced maturation, Gαs(QL) being much more effective than the wt protein. On the other hand, depletion of Gαs, by the use of antisense oligonucleotides, caused spontaneous maturation measured as MAPK activation, indicating clearly that the presence of Gαs is necessary to keep oocytes arrested. Overexpression of three different G‐protein coupled receptors (GPCR), the β2‐adrenergic receptor and the m4 and m5 muscarinic receptors, all caused inhibition of MAPK activation induced by progesterone. These receptors, upon their activation with the respective ligands, might be inducing the release of Gβγ from their respective Gα, which together with endogenous Gαs‐GTP, activate adenylyl cyclase. Our results indicate that Gαs plays an important role in the maturation process and support previous findings of Gβγ participation, suggesting the presence of a mechanism where a constitutively activated Gαs subunit, together with the Gβγ heterodimer, both maintain high levels of intracellular cAMP levels, blocking the G2/M transition. Mol. Reprod. Dev. 63: 104–109, 2002. © 2002 Wiley‐Liss, Inc.
Ran, a GTP‐binding protein involved in nucleocytoplasmic transport and microtubule nucleation, relocates from the manchette to the centrosome region during rat spermiogenesis
Authors: Kierszenbaum Abraham L. , Gil Mara , Rivkin Eugene , Tres Laura L. 
Published: October 2002

AbstractRan, a Ras‐related GTPase, is required for transporting proteins in and out of the nucleus during interphase and for regulating the assembly of microtubules. cDNA cloning shows that rat testis, like mouse testis, expresses both somatic and testis‐specific forms of Ran–GTPase. The presence of a homologous testis‐specific form of Ran–GTPase in rodents implies that the Ran–GTPase pathway plays a significant role during sperm development. This suggestions is supported by distinct Ran–GTPase immunolocalization sites identified in developing spermatids. Confocal microscopy demonstrates that Ran–GTPase localizes in the nucleus of round spermatids and along the microtubules of the manchette in elongating spermatids. When the manchette disassembles, Ran–GTPase immunoreactivity is visualized in the centrosome region of maturing spermatids. The circumstantial observation that fractionated manchettes, containing copurified centrin‐immunoreactive centrosomes, can organize a three‐dimensional lattice in the presence of taxol and GTP, points to the role of Ran–GTPase and associated factors in microtubule nucleation as well as the potential nucleating function of spermatid centrosomes undergoing a reduction process. Electron microscopy demonstrates the presence in manchette preparations of spermatid centrosomes, recognized as such by their association with remnants of the implantation fossa, a dense plate observed only at the basal surface of developing spermatid and sperm nuclei. In addition, we have found importin β1 immunoreactivity in the nucleus of elongating spermatids, a finding that, together with the presence of Ran–GTPase in the nucleus of round spermatids and the manchette, suggest a potential role of Ran–GTPase machinery in nucleocytoplasmic transport. Our expression and localization analysis, correlated with functional observations in other cell systems, suggest that Ran–GTPase may be involved in both nucleocytoplasmic transport and microtubules assembly, two critical events during the development of functional sperm. In addition, the manchette‐to‐centrosome Ran–GTPase relocation, together with the similar redistribution of various proteins associated to the manchette, suggest the existence of an intramanchette molecular transport mechanism, which may share molecular analogies with intraflagellar transport. Mol. Reprod. Dev. 63: 131–140, 2002. © 2002 Wiley‐Liss, Inc.
Intramanchette transport (IMT): Managing the making of the spermatid head, centrosome, and tail
Authors: Kierszenbaum Abraham L. 
Published: October 2002

AbstractIntramanchette transport (IMT) and intraflagellar transport (IFT) share similar molecular components: a raft protein complex transporting cargo proteins mobilized along microtubules by molecular motors. IFT, initially discovered in flagella of Chlamydomonas, has been also observed in cilia of the worm Caenorhabditis elegans and in mouse ciliated and flagellated cells. IFT has been defined as the mechanism by which protein raft components (also called IFT particles) are displaced between the flagellum and the plasma membrane in the anterograde direction by kinesin‐II and in the retrograde direction by cytoplasmic dynein 1b. Mutation of the gene Tg737, encoding one of the components of the raft protein complex, designated Polaris in the mouse and IFT88 in both Chlamydomonas and mouse, results in defective ciliogenesis and flagellar development as well as asymmetry in left‐right axis determination. Polaris/IFT88 is detected in the manchette of mouse and rat spermatids. Indications of an IMT mechanism originated from the finding that two proteins associated with the manchette (Sak57/K5 and TBP‐1, the latter a component of the 26S proteasome) repositioned to the centrosome and sperm tail once the manchette disassembled. IMT has the features of the IFT machinery but, in addition, facilitates nucleocytoplasmic exchange activities during spermiogenesis. An example is Ran, a small GTPase present in the nucleus and cytoplasm of round spermatids and in the manchette of elongating spermatids. Upon disassembly of the manchette, Ran GTPase is found in the centrosome region of elongating spermatids. Because defective molecular motors and raft proteins result in defective flagella, cilia, and cilia‐containing photoreceptor cells in the retina, IMT and IFT are emerging as essential mechanisms for managing critical aspects of sperm development. Details of specific role of Ran GTPase in nucleocytoplasmic transport and its relocation from the manchette to the centrosome to the sperm tail await elucidation. Mol. Reprod. Dev. 63: 1–4, 2002. © 2002 Wiley‐Liss, Inc.
Short‐term reproducibility of cystometry and pressure‐flow micturition studies in healthy women
Authors: Brostrom Soren , Jennum Poul , Lose Gunnar 
Published: October 2002

AbstractAimsTo evaluate the reproducibility of cystometry and pressure flow studies in women. We wanted to explore any clinically relevant effect of repeated, same‐session cystometry.MethodsThirty healthy women with a mean age of 52 years were investigated with repeat medium‐fill water cystometry and pressure‐flow micturition studies in a single session.ResultsLarge test‐retest variability was noted, with wide limits of agreement. Of statistical significance was an increase of first desire (FD) and normal desire (ND), and a decrease in bladder opening pressure. Maximum cystometric capacity was unchanged.ConclusionsAlthough the nature of the conditioning effect of the first fill remains to be explored, the phenomenon could possibly be used for improved urodynamic diagnosis. Neurourol. Urodynam. 21:457–460, 2002. © Wiley‐Liss, Inc.
c‐Fos expression in the spinal cord after acute sacral segmental nerve stimulation
Authors: Ishigooka Manabu , Nakada Teruhiro , Hashimoto Tohru , Zermann Dirk‐Henrik , Schmidt Richard A. 
Published: October 2002

AbstractAimsSacral nerve stimulation (SNS) can provide subjective and objective relief of pelvic pain and chronic voiding symptoms, but its mechanism is poorly understood. It is well known that a noxious stimulus applied to one part of the body can reduce the response to a subsequent stimulus elsewhere in the body. This phenomenon, known as diffuse noxious inhibitory controls (DNIC), seems to be the mechanism by which pain can be reduced by concurrent noxious stimulation.MethodsOn the basis of the DNIC concept, we investigated the expression of a protein product of proto‐oncogene c‐Fos (c‐Fos) in the rat spinal cord after acute electrical stimulation of the sacral segmental nerve with or without lower urinary tract irritation. Adult male Sprague‐Dawley rats were treated either by sacral nerve stimulation (SNS) from the S1 sacral foramen or chemical irritation of the lower urinary tract (LUT) or both. Rats were perfused transcardially, and spinal cords were removed and processed for c‐Fos immunohistochemistry. c‐Fos expression in the central nervous system was detected by immunohistochemistry by using the avidin‐biotin technique. The number of c‐Fos–positive cells and their locations in the spinal cord were evaluated.ResultsSNS and LUT irritation resulted in significant increases in c‐Fos–positive cells in L6 and S1 spinal segments. In the animals treated by SNS and LUT irritation, counts of c‐Fos–positive cells in L6 and S1 segments were significantly smaller than expected. Distribution and number of c‐Fos–positive cells in rats that received SNS and LUT irritation were almost the same as those induced by SNS alone in the S1 segment.ConclusionsSNS alone caused a near maximal response in c‐Fos expression such that adding LUT irritation did not cause a linear increase in c‐Fos. Subsequent LUT irritation could not induce additional expression of c‐Fos within the spinal cord. Neurourol. Urodynam. 21:495–501, 2002. © Wiley‐Liss, Inc.
Environmental exposure to residues after aerial spraying of endosulfan: residues in cow milk, fish, water, soil and cashew leaf in Kasargode, Kerala, India
Authors: Ramesh Atmakuru , Vijayalakshmi Ambalatharasu 
Published: October 2002

AbstractA detailed study has been conducted to evaluate the residues of endosulfan and its principal metabolite (alpha‐endosulfan, beta‐endosulfan and endosulfan sulfate) which may have accumulated in environmental samples due to regular aerial spray application of endosulfan on cashew leaf plantation for a period of 20 years. Three months after the last spray of endosulfan 350 g litre−1 EC at 300 ml acre−1 (equivalent to 105 g AI acre−1 = 42.5 g ha−1), a total of 93 samples of cow milk, fish, water, soil and dried cashew leaf were collected from a village in Kasargode District, Kerala, India, where endosulfan contamination was likely to have occurred. All the samples were analyzed for total residues of endosulfan (comprising alpha‐ and beta‐endosulfan), endosulfan sulfate and also the potential hydrolysis product endosulfan diol, using gas chromatography with electron capture detection. The minimum detection limits of total endosulfan was 0.001 µg g−1. Analysis of soil samples showed the deposition of total endosulfan residues in the range <0.001–0.010 µg g−1, and dried leaf samples showed residues of endosulfan in the range <0.001–3.43 µg g−1 dry weight. In cow milk, fish and water, endosulfan residues could not be detected above the minimum detection limit. Endosulfan diol was not observed in any sample. The data obtained was confirmed by GC‐MS‐EI using selective ion monitoring (SIM) mode.© 2002 Society of Chemical Industry
Characterization of propargyl bromide transformation in soil
Authors: Papiernik Sharon K , Gan Jianying , Yates Scott R 
Published: October 2002

AbstractPropargyl bromide is being investigated for its potential as a soil fumigant. Characterization of the fate of propargyl bromide in soil is important in determining both efficacy and the threat of environmental contamination. These experiments investigated some of the factors affecting the rate of propargyl bromide degradation in soil and quantified some of the products formed as a result of propargyl bromide degradation in four soils of differing composition and at three initial propargyl bromide concentrations. In all soils at all initial propargyl bromide concentrations, equimolar formation of Br− was observed during propargyl bromide degradation, but little propargyl alcohol (product of hydrolysis) was formed. The apparent first‐order degradation coefficient (k) increased with decreasing initial propargyl bromide concentration in all soils, but the mass degraded per unit time increased with increasing propargyl bromide concentration. The rate of propargyl bromide degradation increased with increasing soil organic matter content, and the k value was correlated to the organic carbon content of the soil (correlation coefficient >0.97 for all concentrations). Repeated application of propargyl bromide did not increase the rate of propargyl bromide degradation in soil. Addition of Br− did not affect the rate of propargyl bromide transformation in soil, so accumulation of Br− in the soil is not expected to impede propargyl bromide degradation.Published in 2002 for SCI by John Wiley & Sons, Ltd.
Induction of phytoalexins in pigeonpea (Cajanus cajan) in response to inoculation with Fusarium udum and other treatments
Authors: Marley Paul S , Hillocks Rory J 
Published: October 2002

AbstractCajanol accumulation was monitored in four cultivars of pigeonpea, Cajanus cajan (L) Millsp, after inoculation with 2 × 106 conidia ml−1 of Fusarium udum Butler. Rapid accumulation was observed only in wilt‐resistant cultivar ICP 9145. Another wilt‐resistant cultivar, ICP 8863, had low levels of cajanol similar to those in wilt‐susceptible cultivars ICP 2376 and Malawi local, indicating that rapid cajanol accumulation is not positively correlated with resistance to wilt in pigeonpea. A comparison of various inducing agents showed live conidia of the pathogen to cause more rapid accumulation than the other agents.© 2002 Society of Chemical Industry
Multimedia satellite communications experiments to the international space station
Authors: Matarasso Carlo , Giggenbach Dirk , Hermanns Frank , Lutz Erich 
Published: October 2002

AbstractIn the present concept of the International Space Station ISS, it is planned to provide the communication services between the European Columbus module of the ISS and the ground equipment via the TDRS (tracking and data relay satellite) network provided by the American NASA (National Aeronautics and Space Agency). Especially because of its low uplink data rate, an unacceptable limitation of the communication services with Columbus is to be expected.In order to investigate possible improvements to this situation, the MEDIS proposal studies the feasibility of a 150 Mbps full duplex communication system to the Columbus Module on via two MEO satellites. A mixed topology with optical inter satellite links and Ka‐band up/down‐links shall be employed. Also possible liaisons with the Artemis mission will be considered.The MEDIS project is a collaboration of Astrium GmbH, which is project manager, Bosch SatCom, GMD‐Fokus and the German Aerospace Center (DLR). The preparation phase of the project will investigate the concept of the communications infrastructure and the experiments that could be realized when the MEOs are launched. This stage has been completed in February 2001. An additional study phase followed, which will be completed with a presentation in July 2002.Briefly the following aspects have been studied by DLR in the preparation phase:

the overall concept of experimental communication services for Columbus,

the system requirements and network topology,

the relevant protocol and hardware architectures,

useful satellite constellations and link scenarios.

Two phases could follow the preparation phase, in phase one the satellite will be launched and the link will be tested. In phase two the satellites will be connected to the ISS. Copyright © 2002 John Wiley & Sons, Ltd.
The potential for using LEO telecommunications constellations to support nanosatellite formation flying
Authors: Horan Stephen 
Published: October 2002

AbstractThis is an investigation to determine if a low‐Earth telecommunications constellation can be used to support data services for small satellites also in Low‐Earth Orbit. The intent is to use the telecommunications service provider satellites to supply low‐rate command and telemetry services as well as inter‐satellite data communications. In this study, we determine access potential via simulations of the orbital contact time using current telecommunications constellation configurations and the assumed configuration for a nanosatellite user. From the access times, we conclude that there are sufficient numbers of contacts to permit command and telemetry services for the nanosatellite constellation. In addition to the access time, we consider Doppler effects, antenna effects, and regulatory restrictions on such communications. However, the regulations do not currently permit such operations on a regular basis. From this analysis, we conclude that the desired communications are possible but the nanosatellite user will need to work closely with the service provider. Copyright © 2002 John Wiley & Sons, Ltd.
Realizing active data warehouses with off‐the‐shelf database technology
Authors: Thalhammer Thomas , Schrefl Michael 
Published: October 2002

AbstractActive data warehouses belong to a new category of decision support systems, which automate decision making for routine decision tasks and semi‐routine decision tasks. Just as active database systems extend conventional database systems with event–condition–action rules for integrity constraint enforcement or procedure execution, active data warehouses extend conventional data warehouses with analysis rules that mimic the work of an analyst during decision making. This paper demonstrates how analysis rules can be implemented on top of a passive relational data warehouse system by using commercially available database technology. Copyright © 2002 John Wiley & Sons, Ltd.
The modern dilemma and the challenge to systems thinkers
Authors: Jackson Wes 
Published: October 2002

AbstractIn a world with an exploding human population and declining non‐renewable resources, three kinds of intellectuals weigh in as inquirers into the human prospect. Two agree that the European–North American–Japanese path of development cannot be sustained. The third scholar studiously avoids being drawn into the discussion as he advances a recipe for right livelihood, which ignores economic considerations by advancing a moral argument. Systems thinking, a form of reductionism, it is argued, must remain subordinate to a dialectical approach to solving our problems. Copyright © 2002 John Wiley & Sons, Ltd.
The map of science collaboratory
Authors: Blanco Hilda 
Published: October 2002

AbstractThis paper develops the idea for a program of nationwide collaboratories. It argues that now that we have completed mapping the human genome, we should begin to map its corresponding social unit—the set of instructions that generate/constitute our knowledge. This is a pressing task because of the environmental and population challenges we face in the twenty‐first century, which require well‐informed public policy based on scientific consensus, and because the explosive growth in research and publications makes divergence, and not consensus, more likely. The major tasks of the collaboratory would be to take stock, make accessible and synthesize existing knowledge, to develop further methods for research synthesis/meta‐analysis; to integrate disciplinary research; and to develop methods to visualize scientific findings and their linkages. The paper discusses and documents the explosive growth of the use of meta‐analysis in the medical and other sciences. The program calls for establishing 6–12 collaboratory centers throughout the country that would initially specialize on specific areas, substantive and methodological. Copyright © 2002 John Wiley & Sons, Ltd.
A trusting constructivist approach to systemic inquiry: exploring accountability
Authors: Romm Norma 
Published: October 2002

AbstractThis paper offers an outline of, and justification for, what I call a ‘trusting constructivist’ approach to systemic inquiry. I work with the constructivist view that, as Banathy puts it: ‘what we know about the world becomes projected onto the world’. That is, our theoretical constructions and ways of thinking in relation to the world cannot be considered separately from the impacts that they might have on the unfolding of possibilities. Recognizing our involvement in the development of systems means that we can reconsider—with others—the status of our own constructions as potentially generating self‐fulfilling effects. A trusting constructivist view suggests that people cannot desist from offering their own constructions (that embody particular concerns) in processes of inquiry (professional or otherwise). But they need to recognize the choices that they are making as they create constructions, so that they can account for these in relation to alternatives in social discourse, in an endeavor to earn others' trust. Copyright © 2002 John Wiley & Sons, Ltd.
Biologic tendon fixation to metallic implant augmented with autogenous cancellous bone graft and bone marrow in a canine model
Authors: Inoue Nozomu , Ikeda Kazuo , Aro Hannu T. , Frassica Frank J. , Sim Franklin H. , Chao Edmund Y. S. 
Published: October 2002

AbstractSoft tissue attachment to a metallic prosthesis is required for the improvement of the functional outcome of endoprosthetic reconstructions. Direct tendon attachment to the metallic surface can be achieved through fibrous ingrowth, but such an attachment has a mechanical strength less than one fifth of that of a normal tendon insertion. Regeneration of a transitional structure between the tendon and the metallic surface similar to the normal morphology of a direct tendon insertion may improve the mechanical strength of the new tendon insertion. The objective of the study was to investigate the effect of placement of an interpositional autogenous cancellous bone plate augmented with bone marrow on the mechanical strength of the soft tissue attachment to the metallic surface. The insertion of the supraspinatus tendon was reattached to a porous titanium prosthesis in a canine shoulder model. An autogenous cancellous bone plate supplemented with bone marrow was positioned between the metallic surface and the tendon. Assessment of load‐bearing, as a measure of functional recovery, and radiological analysis were performed at 3, 6, 9, 12, and 15 weeks. The animals were euthanized 16 weeks after surgery, and the specimens were subjected to tensile mechanical testing (six animals) and microradiographic‐histologic evaluation (three animals). Functional analysis showed a 90.3% recovery of preoperative weight‐bearing by 16 weeks (p < 0.05). The mineralized area around the prostheses increased by 63% over time (p < 0.05). Tensile stiffness and strength of the reconstruction were 43.6% and 42.8% of the intact tendon insertion values, respectively. These results were higher than in previous experiments using the direct tendon attachment (p < 0.01, p < 0.05, respectively) or the interpositional bone plate without marrow supplementation (p < 0.05, p < 0.05, respectively). Morphologically, the tendon reattachment site contained the basic tissue transition zones in normal tendon insertion to bone. Inductive bone grafting, supplemented with bone marrow, in the biologic augmentation of tendon anchoring onto a porous metallic prosthesis was an effective technique to increase the mechanical strength of the tendon attachment to the metallic prosthesis.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.