bluuebunny/crossref_metadata_2025 huggingface dataset:
Turnover of primary transcripts is a major step in the regulation of mouse H19 gene expression
Authors: Milligan Laura , Forné Thierry , Antoine Etienne , Weber Michaël , Hémonnot Bénédicte , Dandolo Luisa , Brunel Claude , Cathala Guy
Published: September 2002

In the gene expression pathway, RNA biogenesis is a central multi‐step process where both message fidelity and steady‐state levels of the mature RNA have to be ascertained. An emerging question is whether RNA levels could be regulated at the precursor stage. Until recently, because it was technically very difficult to determine the level of a pre‐mRNA, discrimination between changes in transcriptional activity and in pre‐mRNA metabolism was extremely difficult. H19 RNA, the untranslated product of an imprinted gene, undergoes post‐transcriptional regulation. Here, using a quantitative real‐time RT–PCR approach, we accurately quantify its precursor RNA levels and compare these with the transcriptional activity of the gene, assessed by run‐on assays. We find that the levels of H19 precursor RNA are regulated during physiological processes and this regulation appears to be related to RNA polymerase II transcription termination. Our results provide direct evidence that turnover of polymerase II primary transcripts can regulate gene expression in mammals.
Modification of position‐effect variegation by competition for binding to Drosophila satellites
Authors: Monod Caroline , Aulner Nathalie , Cuvier Olivier , Käs Emmanuel
Published: September 2002

white‐mottled (wm4) position‐effect variegation (PEV) arises by translocation of the white gene near the pericentric AT‐rich 1.688 g/cm3 satellite III (SATIII) repeats of the X chromosome of Drosophila. The natural and artificial A•T‐hook proteins D1 and MATH20 modify wm4 PEV in opposite ways. D1 binds SATIII repeats and enhances PEV, presumably via a recruitment of protein partners, whereas MATH20 suppresses it. We show that D1 and MATH20 compete for binding to identical sites of SATIII repeats in vitro and that conditional MATH20 expression results in a displacement of D1 from pericentric heterochromatin in vivo. In the presence of intermediate levels of MATH20, we show that this displacement becomes selective for SATIII repeats. These results strongly suggest that the suppression of wm4 PEV by MATH20 is due to a displacement of D1 from its preferred binding sites and provide additional support for a direct role of D1 in the assembly of AT‐rich heterochromatin.
Competition between histone H1 and HMGN proteins for chromatin binding sites
Authors: Catez Frédéric , Brown David T , Misteli Tom , Bustin Michael
Published: September 2002

The ability of regulatory factors to access their nucleosomal targets is modulated by nuclear proteins such as histone H1 and HMGN (previously named HMG‐14/‐17 family) that bind to nucleosomes and either stabilize or destabilize the higher‐order chromatin structure. We tested whether HMGN proteins affect the interaction of histone H1 with chromatin. Using microinjection into living cells expressing H1–GFP and photobleaching techniques, we found that wild‐type HMGN, but not HMGN point mutants that do not bind to nucleosomes, inhibits the binding of H1 to nucleosomes. HMGN proteins compete with H1 for nucleosome sites but do not displace statically bound H1 from chromatin. Our results provide evidence for in vivo competition among chromosomal proteins for binding sites on chromatin and suggest that the local structure of the chromatin fiber is modulated by a dynamic interplay between nucleosomal binding proteins.
p21‐activated kinase 1 interacts with and phosphorylates histone H3 in breast cancer cells
Authors: Li Feng , Adam Liana , Vadlamudi Ratna K , Zhou Hongyi , Sen Subrata , Chernoff Jonathan , Mandal Mahitosh , Kumar Rakesh
Published: September 2002

Stimulation of p21‐activated kinase‐1 (Pak1) signaling promotes motility, invasiveness, anchorage‐independent growth and abnormal mitotic assembly in human breast cancer cells. Here, we provide new evidence that, before the onset of mitosis, activated Pak1 is specifically localized with the chromosomes during prophase and on the centrosomes in metaphase and moves to the contraction ring during cytokinesis. To identify mitosis‐specific substrates of Pak1, we screened a synchronized G2–M expression library by using a glutathione transferase Pak1 solid‐phase‐based kinase reaction. This analysis identified histone H3 as a substrate of Pak1 both in vitro and in vivo, and it specifically interacted with Pak1 but not Pak2 or Pak3. Site‐directed mutagenesis indicated that Pak1 phosphorylates histone H3 on Ser10. Expressions of the wild‐type, or catalytically active, Pak1 caused it to appear at the poles corresponding to mitotic centrosomes in a variety of mammalian cells. Together, these results suggest for the first time that Pak1 interacts with and phosphorylates histone H3 and may thus influence the Pak1–histone H3 pathway, which in turn may influence mitotic events in breast cancer cells.
Dealing with osmostress through MAP kinase activation
Authors: de Nadal Eulàlia , Alepuz Paula M , Posas Francesc
Published: September 2002

In response to changes in the extracellular environment, cells coordinate intracellular activities to maximize their probability of survival and proliferation. Eukaryotic cells, from yeast to mammals, transduce diverse extracellular stimuli through the cell by multiple mitogen‐activated protein kinase (MAPK) cascades. Exposure of cells to increases in extracellular osmolarity results in rapid activation of a highly conserved family of MAPKs, known as stress‐activated MAPKs (SAPKs). Activation of SAPKs is essential for the induction of adaptive responses required for cell survival upon osmostress. Recent studies have begun to shed light on the broad effects of SAPK activation in the modulation of several aspects of cell physiology, ranging from the control of gene expression to the regulation of cell division.
The Electoral Geography of Weimar Germany: Exploratory Spatial Data Analyses (ESDA) of Protestant Support for the Nazi Party
Authors: O'Loughlin John
Published: September 2002

For more than half a century, social scientists have probed the aggregate correlates of the vote for the Nazi party (NSDAP) in Weimar Germany. Since individual-level data are not available for this time period, aggregate census data for small geographic units have been heavily used to infer the support of the Nazi party by various compositional groups. Many of these studies hint at a complex geographic patterning. Recent developments in geographic methodologies, based on Geographic Information Science (GIS) and spatial statistics, allow a deeper probing of these regional and local contextual elements. In this paper, a suite of geographic methods—global and local measures of spatial autocorrelation, variography, distance-based correlation, directional spatial correlograms, vector mapping, and barrier definition (wombling)—are used in an exploratory spatial data analysis of the NSDAP vote. The support for the NSDAP by Protestant voters (estimated using King's ecological inference procedure) is the key correlate examined. The results from the various methods are consistent in showing a voting surface of great complexity, with many local clusters that differ from the regional trend. The Weimar German electoral map does not show much evidence of a nationalized electorate, but is better characterized as a mosaic of support for “milieu parties,” mixed across class and other social lines, and defined by a strong attachment to local traditions, beliefs, and practices.
Location, Location, Location: An MCMC Approach to Modeling the Spatial Context of War and Peace
Authors: Ward Michael D. , Gleditsch Kristian Skrede
Published: September 2002

This article demonstrates how spatially dependent data with a categorical response variable can be addressed in a statistical model. We introduce the idea of an autologistic model where the response for one observation is dependent on the value of the response among adjacent observations. The autologistic model has likelihood function that is mathematically intractable, since the observations are conditionally dependent upon one another. We review alternative techniques for estimating this model, with special emphasis on recent advances using Markov chain Monte Carlo (MCMC) techniques. We evaluate a highly simplified autologistic model of conflict where the likelihood of war involvement for each nation is conditional on the war involvement of proximate states. We estimate this autologistic model for a single year (1988) via maximum pseudolikelihood and MCMC maximum likelihood methods. Our results indicate that the autologistic model fits the data much better than an unconditional model and that the MCMC estimates generally dominate the pseudolikelihood estimates. The autologistic model generates predicted probabilities greater than 0.5 and has relatively good predictive abilities in an out-of-sample forecast for the subsequent decade (1989 to 1998), correctly identifying not only ongoing conflicts, but also new ones.
Spatially Dispersed Ties Among Interdependent Citizens: Connecting Individuals and Aggregates
Authors: Baybeck Brady , Huckfeldt Robert
Published: September 2002

A continuing tradition in contextual analysis locates individual citizens within spatially defined, aggregate settings in an effort to provide a more complete account of individual behavior. Given the increasing individual mobility within society, it is less than clear that geography continues to define the boundaries on meaningful aggregate contexts—people have become less tied to their geographic contexts, and technology makes it possible for citizens to maintain relationships independently of space, distance, and location. In this paper we pursue an analysis and set of analytic techniques that are designed to connect individual voters, their communication networks, and the geography that surrounds them. The analytic techniques utilize a unique data set that captures spatial dispersion in an individual's social and political network, and from these analyses we can draw two conclusions. First, spatial dispersion in a network does have an effect on interaction within the network; the world is not full of voters who operate independently of their geographic contexts. Second, spatial dispersion provides opportunities to connect citizens living in different geographic contexts, thereby creating bridges for communication across different contexts. These findings suggest that scholars might profitably incorporate geography as an important component of the complex relationships among and between individual citizens in explaining the role of the individual in modern democratic politics.
Isolating Spatial Autocorrelation, Aggregation Bias, and Distributional Violations in Ecological Inference: Comment on Anselin and Cho
Authors: King Gary
Published: September 2002

Few better ways of checking and improving statistical methods exist than having other researchers go over your results, and so I especially appreciate the efforts in Anselin and Cho (2002), hereinafter AC. In this note, I make two main points.
Conducting composites as cable anodes in cathodic protection: a literature summary
Authors: Darowicki Kazimierz , Orlikowski Juliusz
Published: September 2002

The basic characteristics of a cathodic protection system, using cable anodes, have been reviewed. Cable anodes differ from typical anode systems because of the anode installation method. An anode system based on cable anodes is not installed in point locations; the anode is located at a small distance from the protected structure and runs in parallel along the route of the structure to be protected. An elastic conducting composite of very good mechanical properties is used as the anode material. This solution can result in a reduction in operating costs, and the avoidance of under‐protected and over‐protected zones, or protective current interference, on other structures.
Study of the effect of AC‐interference on the cathodic protection of a gas pipeline
Authors: Kouloumbi N. , Batis G. , Kioupis N. , Kioupis N. , Asteridis P.
Published: September 2002

The aim of this fieldwork was the study of the effect of 50Hz AC, induced by high‐voltage power lines, on the cathodic protection system of a natural gas pipeline. The effectiveness of cathodic protection was checked through in situ long‐term monitoring and analysis of pipeline electrical parameters. The results gave an insight into the problems of the cathodic protection system operation, caused by AC interference. An AC and DC potential interdependence was observed, that previously has hardly been reported, and was scrutinized in relation to cathodically protected pipelines. The effects of the AC‐interference and low frequency DC potential fluctuations, as well as the potential deviations from the protection potential, are examined. These phenomena are associated with corrosion susceptibility and difficulties in obtaining reliable cathodic protection measurements.
Comparison of the efficiencies of anticorrosive pigments based on chemically modified phosphates
Authors: Kalendová A.
Published: September 2002

The paper deals with the study of modified phosphate compounds and their anticorrosion action when incorporated in paints. The pigments commence as zinc orthophosphate, the modification of which can give phosphosilicates, phosphomolybdates, or basic phosphates. With respect to cations, the combination of zinc with calcium, strontium, barium, or aluminium, is possible. The modified anticorrosive pigments differ in their water solubility, inhibition efficiency of the aqueous extracts, and anticorrosion action, when incorporated in organic coatings. Nine types of modified phosphates were studied. The effect in coatings of organic inhibitor in the presence of anticorrosive inorganic pigments was determined.
Lifelong learning through the Virtual University
Authors: Evans Chris , Ping Fan Jing
Published: September 2002

Lifelong learning has come to involve a variety of learning experiences. These include conventional campus teaching, workplace open learning, modular flexible learning programmes, correspondence‐based distance learning courses, and most recently Web or multimedia‐based courseware. This paper considers the use of multimedia environments for open, flexible and distance education, in particular a learning environment known as the “Virtual University” as part of a process of lifelong learning. A comparison of different modes of learning is made. The Virtual University consists of virtual lectures, virtual seminars, virtual tutorials and virtual exams. It has a number of advantages over both formal lectures and conventional open learning materials, such as interactivity, adaptation, simulation, demonstration and integration. A questionnaire survey was conducted to assess the effectiveness of the Virtual University, and the results indicate an enhancement of the overall learning experience.
The impact of team leader performance on team member satisfaction: the subordinate’s perspective
Authors: Jeanquart Miles Sandy , Mangold Glynn
Published: September 2002

The focus of this paper was twofold: to examine critical team leader behaviors (as perceived by the subordinate) that result in team member satisfaction; and to determine if there is a significant difference between the perceptions of team leaders and team members regarding the level of team satisfaction and factors that predict team leader performance. Results indicate that team member satisfaction was influenced by: the extent to which communication within the group was open; and the team leaders’ performance. Team leader performance was influenced by the team members’ satisfaction with their leaders’ ability to resolve conflicts and the teams’ openness in communication. Team members’ and leaders’ perceptions did not differ significantly regarding open communication in the group, however, team members assessed their leaders’ performance less favorably than the team leaders assessed themselves and were less satisfied with the team leaders’ ability to resolve conflicts.
Teams in Teleland: working effectively in geographically dispersed teams in the Asia Pacific
Authors: Fontaine Gary
Published: September 2002

In the Asia Pacific, along with the rest of the world, there has been a rapid expansion in the use of geographically dispersed teams playing pivotal organizational and interorganizational roles. Yet our understanding of the conditions nurturing the task effectiveness of those teams is still embryonic. This article examines conceptual issues associated with the impact of culture, geography and technology in those teams in the Asia Pacific. It identifies the pivotal role played by “a sense of presence” (the feeling of “being there” with team members in different places and often different times) in both the effectiveness of, and satisfaction in, the use of such teams. Current research designed to explore these issues in teams in business and education in the region is described.
Using reflective learning journals to improve individual and team performance
Authors: Loo Robert , Thorpe Karran
Published: September 2002

This paper describes the successful application of reflective learning journals to promote critical self‐awareness and improve both individual and team performance among members in 11 management undergraduate teams conducting management research projects. Qualitative analyses of the journals revealed several major themes; for example, management skills development, leadership, team communications, stresses of team work, and individual versus team work. Analyses of the journaling evaluation data showed that participants found journaling a useful learning tool. Recommendations are presented for those interested in using reflective learning journals to improve individual and team performance.
Binding site stoichiometry and the effects of phosphorylation on human α1 homomeric glycine receptors
Authors: Gentet Luc J. , Clements John D.
Published: September 2002

The kinetic properties of the human α1 homomeric glycine receptor were investigated. Receptors were expressed in HEK 293 cells, and glycine was applied to outside‐out membrane patches with sub‐millisecond solution exchange. The activation time course of the glycine response was used to investigate receptor stoichiometry. The unbinding of three strychnine molecules and the cooperative binding of two glycine molecules were required to activate the channel. The effects of phosphorylation on glycine receptor kinetics were investigated by pretreating cells with phosphorylators or with phosphatases. Phosphorylation accelerated desensitisation, but slowed deactivation and recovery from desensitisation. A chemical‐kinetic model was developed that reproduced the experimental observations. The model suggests that only three binding sites on the glycine channel are functional, while the remaining two binding sites are ‘silent’, possibly due to strong negative cooperativity.
Role of synaptic inhibition in turtle respiratory rhythm generation
Authors: Johnson Stephen M. , Wilkerson Julia E. R. , Wenninger Michael R. , Henderson Daniel R. , Mitchell Gordon S.
Published: September 2002

In vitro brainstem and brainstem‐spinal cord preparations were used to determine the role of synaptic inhibition in respiratory rhythm generation in adult turtles. Bath application of bicuculline (a GABAA receptor antagonist) to brainstems increased hypoglossal burst frequency and amplitude, with peak discharge shifted towards the burst onset. Strychnine (a glycine receptor antagonist) increased amplitude and frequency, and decreased burst duration, but only at relatively high concentrations (10‐100 μM). Rhythmic activity persisted during combined bicuculline and strychnine application (50 μM each) with increased amplitude and frequency, decreased burst duration, and a rapid onset‐decrementing burst pattern. The bicuculline‐strychnine rhythm frequency decreased during μ‐opioid receptor activation or decreased bath PCO2. Synaptic inhibition blockade in the brainstem of brainstem‐spinal cord preparations increased burst amplitude in spinal expiratory (pectoralis) nerves and nearly abolished spinal inspiratory activity (serratus nerves), suggesting that medullary expiratory motoneurons were mainly active. Under conditions of synaptic inhibition blockade in vitro, the turtle respiratory network was able to produce a rhythm that was sensitive to characteristic respiratory stimuli, perhaps via an expiratory (rather than inspiratory) pacemaker‐driven mechanism. Thus, these data indicate that the adult turtle respiratory rhythm generator has the potential to operate in a pacemaker‐driven manner.
Activation of different vestibular subnuclei evokes differential respiratory and pressor responses in the rat
Authors: Xu Fadi , Zhuang Jianguo , Zhou Tong‐Ron , Gibson Tonya , Frazier Donald T.
Published: September 2002

Activation of the vestibular system can either increase or decrease ventilation. The objectives of the present study were to clarify whether these different responses are the result of activating different vestibular subnuclei, by addressing three questions. Do neurones within the medial, lateral and spinal vestibular nuclei (VNM, VNL and VNS, respectively) function differently in respiratory modulation? Is the ventral medullary nucleus gigantocellularis (NGC) required to fully express the VN‐mediated respiratory responses? Is glutamate, by acting on N‐methyl‐d‐aspartic acid (NMDA) receptors in the vestibular subnuclei, capable of modulating respiration? In anaesthetized, tracheotomized and spontaneously breathing rats, electrical stimuli (< 10 s) applied in the VNL and VNS significantly elevated ventilation by 35 % and 30 % (P < 0.05), respectively. However, VNM stimulation produced statistically significant (P < 0.05) changes that differed depending upon the stimulation site: either ventilatory inhibition (by 40 % in 57 % of the trials) or excitation (by 55 % in 43 % of trials), and which were often accompanied by a pressor response. These electrical‐stimulation‐evoked cardiorespiratory responses were almost eliminated following microinjection of ibotenic acid into the stimulation sites (P < 0.05) or bilaterally into the NGC (P < 0.05). As compared to vehicle, microinjection of NMDA into the unilateral VNM, VNL and VNS significantly increased ventilation to 74 %, 58 % and 60 % (P < 0.05), respectively, with no effect on arterial blood pressure. These data suggest that neurones within the vestibular subnuclei play different roles in cardiorespiratory modulation, and that the integrity of the NGC is essential for the full expression of these VN‐mediated responses. The evoked respiratory excitatory responses are probably mediated by glutamate acting on NMDA receptors, whereas the neurotransmitters involved in VNM‐mediated respiratory inhibition and hypertension remain unknown.
Effects of Mg2+ and SR luminal Ca2+ on caffeine‐induced Ca2+ release in skeletal muscle from humans susceptible to malignant hyperthermia
Authors: Duke Adrian M. , Hopkins Philip M. , Steele Derek S.
Published: September 2002

Regulation of the ryanodine receptor (RYR) by Mg2+ and SR luminal Ca2+ was studied in mechanically skinned malignant hyperthermia susceptible (MHS) and non‐susceptible (MHN) fibres from human vastus medialis. Preparations were perfused with solutions mimicking the intracellular milieu and changes in [Ca2+] were detected using fura‐2 fluorescence. At 1 mm cytosolic Mg2+, MHS fibres had a higher sensitivity to caffeine (2‐40 mm) than MHN fibres. The inhibitory effect of Mg2+ on caffeine‐induced Ca2+ release was studied by increasing [Mg2+] of the solution containing 40 mm caffeine. Increasing [Mg2+] from 1 to 3 mm reduced the amplitude of the caffeine‐induced Ca2+ transient by 77 ± 7.4 % (n= 8) in MHN fibres. However, the caffeine‐induced Ca2+ transient decreased by only 24 ± 8.1 % (n= 9) in MHS fibres. In MHN fibres, reducing the Ca2+ loading period from 4 to 1 min (at 1 mm Mg2+) decreased the fraction of the total sarcoplasmic reticulum (SR) Ca2+ content released in response to 40 mm caffeine by 90.4 ± 6.2 % (n= 6). However, in MHS fibres the response was reduced by only 31.2 ± 17.4 % (n= 6) under similar conditions. These results suggest that human malignant hyperthermia (MH) is associated with reduced inhibition of the RYR by (i) cytosolic Mg2+ and (ii) SR Ca2+ depletion. Both of these effects may contribute to increased sensitivity of the RYR to caffeine and volatile anaesthetics.
Contraction‐related factors affect the concentration of a kallidin‐like peptide in rat muscle tissue
Authors: Boix Fernando , Rosenborg Laila , Hilgenfeldt Ulrich , Knardahl Stein
Published: September 2002

In order to study the effects of the manipulation of various factors related to muscular activity on the concentration of kinins in muscular tissue, a microdialysis probe was implanted in the adductor muscle of the hindlimb in anaesthetized rats. After collection of baseline samples, the perfusion fluid was changed to a Ringer solution containing sodium lactate (10 or 20 mm), adenosine (50 or 100 μM) or a lower pH (7.0 or 6.6). Whereas perfusion with lactate did not have any significant effect on the concentration of kinins in the dialysate, the perfusion with a lower pH or with adenosine dose‐dependently increased the kinin content in the samples. In a second microdialysis experiment, by using specific radioimmunoassays (RIA) for bradykinin and kallidin, we observed that about 70 % of the total kinins dialysed from rat muscle are a kallidin‐like peptide. Also, the simultaneous perfusion with 100 μM caffeine totally abolished the increase in kinin levels induced by the perfusion at pH 6.6. In a third experiment, soleus muscles from rat were stimulated in vitro during 30 min in the presence or absence of 77 μM caffeine. Electrically stimulated contraction, but not the addition of 10 mU ml−1 insulin, induced an increase in the concentration of the kallidin‐like peptide in the buffer. This effect was totally prevented by the addition of the adenosine antagonist caffeine. These results show that a kallidin‐like peptide is released from rat muscle, and that its production is enhanced by muscle activity. Furthermore, the increase in kinin peptides during muscle contraction may be mediated by an increase in adenosine levels.
Sarcoplasmic reticulum calcium load regulates rat arterial smooth muscle calcium sparks and transient KCa currents
Authors: Cheranov Serguei Y. , Jaggar Jonathan H.
Published: September 2002

The regulation of calcium (Ca2+) sparks and transient calcium‐sensitive K+ (KCa) currents by acute changes in sarcoplasmic reticulum (SR) Ca2+ load ([Ca2+]SR) was investigated in rat cerebral artery smooth muscle cells using laser‐scanning confocal microscopy in combination with patch clamp electrophysiology. [Ca2+]SR was elevated by: (i) increasing the activity of the SR Ca2+‐ATPase with an anti‐phospholamban monoclonal antibody, or (ii) blocking Ca2+ release from the SR with tetracaine, a membrane‐permeant, reversible ryanodine‐sensitive Ca2+ release (RyR) channel blocker. Alternatively, [Ca2+]SR was progressively decreased over time with a low concentration of thapsigargin (20 nm), a SR Ca2+‐ATPase blocker. An elevation in [Ca2+]SR increased Ca2+ spark and transient KCa current frequency, but did not alter the amplitude, decay or spatial spread of Ca2+ sparks or the coupling ratio or amplitude correlation between Ca2+ sparks and evoked transient KCa currents. Decreasing [Ca2+]SR reduced Ca2+ spark frequency, amplitude and spatial spread and this reduced transient KCa current frequency and amplitude. However, even when mean Ca2+ spark amplitude and spread decreased by up to 47 and 56 % of control, respectively, the coupling ratio or amplitude correlation between Ca2+ sparks and transient KCa currents was not affected. These data demonstrate that acute changes in [Ca2+]SR regulate Ca2+ sparks and transient KCa currents in arterial smooth muscle cells.
Nicotinic acid adenine dinucleotide phosphate (NAADP) is present at micromolar concentrations in sea urchin spermatozoa
Authors: Billington Richard A. , Ho Andrew , Genazzani Armando A.
Published: September 2002

Nicotinic acid adenine dinucleotide phosphate (NAADP) has been shown to induce Ca2+ release in numerous cellular models, ranging from marine invertebrates to mammals. However, endogenous levels of this pyridine dinucleotide have yet to be demonstrated. In the sea urchin egg, NAADP receptors are abundant but have the peculiarity of being inactivated at low concentrations (picomolar) and activated at higher concentrations (nanomolar) which apparently rules out any possibility of the receptor being activated by concentration rises induced by a slow enzymatic formation in the cytosol. One of the most important events of fertilization is a Ca2+ transient in the egg, which leads to egg activation. The mechanisms which underlie the transient are still unclear and several theories persist including the existence of a sperm receptor and that soluble factors may pass from the sperm to the egg cytosol. We have investigated the possibility that NAADP might be present in sperm. Indeed, we found that sea water‐activated spermatozoa are able to synthesize NAADP and that sperm extracts contain micromolar concentrations of the messenger. Although it is unlikely that NAADP alone mediates the fertilization wave, our data suggest that transfer of NAADP from spermatozoa to egg may play a role in this phenomenon.
Is posthumous semen retrieval ethically permissible?
Authors: Orr R D , Siegler M
Published: September 2002

It is possible to retrieve viable sperm from a dying man or from a recently dead body. This sperm can be frozen for later use by his wife or partner to produce his genetic offspring. But the technical feasibility alone does not morally justify such an endeavour. Posthumous semen retrieval raises questions about consent, the respectful treatment of the dead body, and the welfare of the child to be.

We present two cases, discuss these three issues, and conclude that such requests should generally not be honoured unless there is convincing evidence that the dead man would want his widow to carry and bear his child. Even with consent, the welfare of the potential child must be considered.
Rationing of expensive medical care in a transition country—nihil novum?
Authors: Krízová E , Šimek J
Published: September 2002

This article focuses on rationing of expensive medical care in the Czech Republic. It distinguishes between political and clinical decision levels and reviews the debate in the Western literature on explicit and implicit rules. The contemporary situation of the Czech health care system is considered from this perspective. Rationing reoccurred in the mid 90s after the shift in health care financing from fee-for-service to prospective budgets. The lack of explicit rules is obvious. Implicit forms of rationing, done by physicians at the clinical level prevail, implying uncontrolled power of the medical profession and lacking transparency for ethical considerations of equity to access. It seems to be acceptable for physicians to play the role of allocators, probably because of their experience with rationing during the socialist period. Traditional rationing stereotypes from the previous regime seem to persist despite the health care system transformation during the 90s.
New governance arrangements for research ethics committees: is facilitating research achieved at the cost of participants’ interest
Authors: Cave E , Holm S
Published: September 2002

This paper examines the UK’s response to a recent European Clinical Trials Directive, namely the Department of Health, Central Office for Research Ethics Committee guidance,Governance Arrangements for NHS Research Ethics Committees. The revisions have been long awaited by researchers and research ethics committee members alike. They substantially reform the ethical review system in the UK. We examine the new arrangements and argue that though they go a long way toward addressing the uncertainty surrounding ethics committee function, the system favours the facilitation of research over the protection of the dignity and welfare of research participants.
Informed consent of the minor. Implications of present day Spanish law
Authors: Pérez-Cárceles M D , Osuna E , Luna A
Published: September 2002

In Spain, any person under the age of 18 is a minor. Generally, minors lack the legal capacity to take legally binding actions because they are deemed incapable of legally binding consent. Spanish civil law recognises, however, that the child, in accordance with the law and being sufficiently mature, may act for himself. It stands, then, that consent, as expressed by the “sufficiently mature” minor, should be legally valid.
Pushing and pulling in association with low back and shoulder complaints
Authors: Hoozemans M J M , van der Beek A J , Frings-Dresen M H W , van der Woude L H V , van Dijk F J H
Published: September 2002

Aims:To examine the association between exposure to pushing/pulling at work and low back and shoulder complaints.

Methods:A cross sectional questionnaire survey was carried out among 434 workers from several companies with mainly pushing/pulling tasks. From the same companies 188 workers without physically demanding tasks served as reference. The questionnaire was used to assess the exposure to pushing/pulling and other physical risk factors for low back and shoulder complaints. Mean scores at company level were used to classify groups into medium and high exposed to pushing/pulling and a reference group. Psychosocial factors at work were also assessed. Several pain related questionnaires were used to assess the 12 month prevalence of low back and shoulder complaints in three dimensions: trouble (ache, pain, discomfort), pain intensity, and disability. Prevalence rate ratios (PRs) were calculated using Cox’s proportional hazards regression analysis.

Results:The 12 month prevalence of low back complaints was almost equal for all three groups. The prevalence of shoulder complaints increased with an increase in exposure level. Adjusted PRs showed that the high exposed group had an increased risk for low back complaints compared to the reference group. For all dimensions of shoulder complaints a clear tendency towards a dose–response relation was observed. The high exposed group had significant PRs for shoulder complaints, ranging from 2.09 to 6.37. Generally, psychosocial factors had a confounding effect for pain intensity and disability, but not for trouble.

Conclusions:For shoulder complaints a dose–response relation was observed for exposure to pushing/pulling. Low back complaints were less consistently associated with pushing/pulling. Stronger associations were observed for more severe cases of low back and shoulder complaints. It is hypothesised that work related psychosocial factors affect these associations.
Fatigue as a predictor of work disability
Authors: van Amelsvoort L G P M , Kant I J , Beurskens A J H M , Schröer C A P , Swaen G M H
Published: September 2002

The objective of this study was to assess the predictive value of fatigue for work disability on medical grounds within the framework of a large prospective cohort study. Analyses were carried out on the data of 10 927 employees with a follow up of 32 months. We found that fatigue, as measured with the Checklist Individual Strength, was a strong predictor of subsequent permanent work disability. The for age, gender, presence of a chronic medical condition, and educational level adjusted relative risks were, for the 2nd, 3rd, and 4th fatigue score quartile against the first, respectively: 2.17 (1.17–4.03), 3.30 (1.67–6.52), and 12.8 (5.14–32.1).
HIV associated thrombotic microangiopathy
Authors: Ahmed S , Siddiqui R K , Siddiqui A K , Zaidi S A , Cervia J
Published: September 2002

Thrombotic microangiopathy (TMA) is a known complication of HIV infection. Endothelial cell injury appears to be the primary event causing platelet activation and deposition in the microvasculature. Direct cytopathic roles of HIV as well as other factors such as malignancy, drugs, and infectious agents have been implicated in the pathogenesis of HIV-TMA. Although the the majority of patients present in a more advanced stage of HIV disease, TMA can be the initial presenting symptom of HIV infection. Clinical features are those of idiopathic TMA, and the diagnosis should be suspected in any patient with new onset thrombocytopenia and microangiopathic haemolytic anaemia. Therapy with plasma exchange or infusion appears to be efficacious. A rapid diagnosis and institution of plasmapheresis is crucial for a favourable outcome. The long term prognosis of HIV-TMA is unfavourable and may depend on the stage of HIV infection. The recent data after the use of highly active retroviral treatment, however, are unavailable and current prognosis is therefore uncertain.
Early recognition of diabetic neuropathy: evaluation of a simple outpatient procedure using thermal perception
Authors: Viswanathan V , Snehalatha C , Seena R , Ramachandran A
Published: September 2002

Objective

To determine the effectiveness of Tip-therm, a temperature discriminator, in making an early diagnosis of distal symmetrical polyneuropathy in diabetic patients and to compare its effectiveness with the Semmes-Weinstein monofilament and biothesiometry, which are established methods of diagnosing neuropathy in diabetic patients.

Patients and methods

From the diabetic subjects who came to the hospital for review, 910 consecutive cases were selected. All were tested with the Semmes-Weinstein monofilament (10 g monofilament) and biothesiometry and also by using the Tip-therm for comparison.

Results

Out of the 241 patients who had no sensation to the monofilament only four (1.7%) felt Tip-therm whereas 237 (98.3%) patients could not feel Tip-therm. Among 298 patients diagnosed as having neuropathy by biothesiometry, only eight (2.7%) patients exhibited sensation with Tip-therm while 290 (97.3%) patients could not feel it.

Conclusion

A simple device, Tip-therm, which tests for temperature discrimination, was compared with two validated methods for detection of neuropathy—a monofilament and biothesiometry. Tip-therm appears to be an inexpensive, highly sensitive, and specific device for detection of diabetic neuropathy when compared with biothesiometry and a monofilament.
National audit of the management of peritonsillar abscess
Authors: Mehanna H M , Al-Bahnasawi L , White A
Published: September 2002

An anonymous postal survey of 200 consultants was used to audit the current prevalent practices in the management of quinsy in the UK; 101 responded. The findings reveal that on average an otolaryngology department treats 29 cases per year, the vast majority (94%) on an inpatient basis. The main initial treatment was needle aspiration combined with intravenous antibiotics. Interestingly, those departments treating more than 20 cases a year are more likely to use needle aspiration, while departments in England and Wales use significantly more incision and drainage than those in Scotland. Incision and drainage (52%) was the most common form of treatment of non-resolving patients. The median hospital stay was two days.
Estimating liquefaction-induced ground settlements from CPT for level ground
Authors: Zhang G , Robertson P K , Brachman R W.I
Published: September 2002

An integrated approach to estimate liquefaction-induced ground settlements using CPT data for sites with level ground is presented. The approach combines an existing CPT-based method to estimate liquefaction resistance with laboratory test results on clean sand to evaluate the liquefaction-induced volumetric strains for sandy and silty soils. The proposed method was used to estimate the settlements at both the Marina District and Treasure Island sites damaged by liquefaction during the Loma Prieta, California, earthquake on 17 October 1989. Good agreement between the calculated and measured liquefaction-induced ground settlements was found. The major factors that affect the estimation of liquefaction-induced ground settlements are also discussed in detail. The recommendations for taking the effects of these factors into account in estimating liquefaction-induced ground settlements using the proposed CPT-based approach are presented. It is suggested that the proposed method may be used to estimate liquefaction-induced settlements for low- to medium-risk projects and also to provide preliminary estimates for higher risk projects.Key words: liquefaction, settlements, earthquake, sand, in situ testing.
Use of the grain-size distribution for estimation of the soil-water characteristic curve
Authors: Fredlund Murray D , Wilson G Ward , Fredlund Delwyn G
Published: September 2002

The implementation of unsaturated soil mechanics into engineering practice is dependent, to a large extent, upon an ability to estimate unsaturated soil property functions. The soil-water characteristic curve (SWCC), along with the saturated soil properties, has proven to provide a satisfactory basis for estimating the permeability function and shear strength functions for an unsaturated soil. The volume change functions have not been totally defined nor applied in geotechnical engineering. The objective of this paper is to present a procedure for estimating the SWCC from information on the grain-size distribution and the volumemass properties of a soil. SWCCs represent a continuous water content versus soil suction relationship. The proposed method provides an approximate means of estimating the desorption curve corresponding to a soil initially slurried near the liquid limit. The effects of stress history, fabric, confining pressure, and hysteresis are not addressed. A database of published data is used to verify the proposed procedure. The database contains independent measurements of the grain-size distribution and the SWCC. The level of fit between the estimated and measured SWCCs is analyzed statistically. The proposed procedure is compared to previously proposed methods for predicting the SWCC from the grain-size distribution. The results show that the proposed procedure is somewhat superior to previous methods.Key words: soil-water characteristic curve, grain-size distribution, volume-mass properties, pedo-transfer function, unsaturated soil property functions.
Vacuum and surcharge combined one-dimensional consolidation of clay soils
Authors: Mohamedelhassan E , Shang J Q
Published: September 2002

In this study, a vacuum and surcharge combined one-dimensional consolidation model is developed. Terzaghi's consolidation theory is revisited by applying the initial and boundary conditions corresponding to combined vacuum and surcharge loading on a soil. A test apparatus is designed, manufactured, and assembled to verify the model. The apparatus has the capacity of applying designated vacuum and surcharge pressures to a soil specimen, and it allows for the measurement of the excess pore-water pressure, settlement, and volume change during the consolidation process. Two series of tests are performed using the apparatus on two reconstituted natural clay soils, namely, the Welland sediment at water contents close to its liquid limit and the Orleans clay, reconstituted and consolidated under an effective stress of 60 kPa. The former test series mimics the strengthening of a very soft soil, such as the hydraulic fill used in land reclamation. The latter test series is designed to study vacuumsurcharge combined strengthening of a consolidated soil. It is demonstrated from the experiments that the one-dimensional vacuum-surcharge consolidation model describes the consolidation behaviour of both soils well. The consolidation characteristics of the soils show no discrimination against the nature of the consolidation pressure, namely, whether they are consolidated under the vacuum pressure alone, under the surcharge pressure alone, or under a pressure generated by the combined application of vacuum and surcharge. The study concluded that the soil consolidation characteristics obtained from the conventional consolidation tests can be used in the design of vacuum preloading systems, provided that the one-dimensional loading condition prevails.Key words: consolidation, soil improvement, vacuum pressure, surcharge pressure, excess pore-water pressure, soil consolidation parameters.
On measuring creep behaviour in granular materials through triaxial testing
Authors: Kuwano Reiko , Jardine Richard J
Published: September 2002

The first part of the paper describes the precision and long-term stability that are required in triaxial stress-strain measurements and in stress-path control systems to obtain reliable information on creep in granular media. It is shown that membrane penetration and sample end compliance must be accounted for and that lubricated ends and local strain measurements are essential. The temperature sensitivity of each transducer also needs to be assessed, even when working in a temperature-controlled laboratory. The second part of the paper presents illustrative data that were obtained in tests on sand and Ballotini® glass beads. Considerable creep deformations were observed under both isotropic and anisotropic effective stress conditions, even at relatively low pressures where particle breakage was unlikely to be significant. The experiments show how creep depends on the stress conditions imposed, how the strain increment directions change during creep, and how the creep rates stabilize with time.Key words: sand, creep, triaxial test, yielding, membrane penetration.
DECOMPOSITIONS OF PLANAR HOMEOMORPHISMS USING COMPUTER SOFTWARE
Authors: CHO IL YEUN , OCHIAI MITSUYUKI , SAKATA YOSHIKO
Published: September 2002

We have established in [S3] an algorithm with a new data structure that decomposes gluing homeomorphisms of 3-manifolds given by planar Heegaard diagrams into a product of canonical Dehn's twists. To support this study, we developed a computer software called Decomposition of Planar Homeomorphisms (Genus 3) that automatically decomposes the self homeomorphis of a closed connected surface given by any planar Heegaard diagram of genus 3 into a product of canonical Dehn's twists. In this paper, we demonstrate the content and the implementation that this software holds and also show its availability.
Iron Overload Augments Angiotensin II–Induced Cardiac Fibrosis and Promotes Neointima Formation
Authors: Ishizaka Nobukazu , Saito Kan , Mitani Haruo , Yamazaki Ieharu , Sata Masataka , Usui Shin-ichi , Mori Ichiro , Ohno Minoru , Nagai Ryozo
Published: September 2002

Background—

Abnormal iron deposition may cause oxidant-induced damage in various organs. We have previously reported that continuous administration of angiotensin II to rats results in an overt iron deposition in the renal tubular epithelial cells, which may have a role in angiotensin II–induced renal damage. In the present study, we investigated the role of iron in the development of cardiac injury induced by angiotensin II.

Methods and Results—

Angiotensin II was continuously infused to rats at a dose of 0.7 mg/kg per day for 7 consecutive days. No iron deposits were observed in the hearts of untreated rats, whereas iron deposition was seen in the cells in the subepicardial and granulation regions after angiotensin II infusion. Concomitant administration of deferoxamine, an iron chelator, significantly reduced the extent of cardiac fibrosis, which suggests that iron deposition aggravates the cardiac fibrosis induced by angiotensin II. Iron overload caused by the administration of iron-dextran resulted in an augmentation of cardiac fibrosis and the generation of neointimal cells in the coronary artery in angiotensin II–infused rats. By contrast, neointima was not formed in the cardiac vessels in norepinephrine-infused rats with iron overload.

Conclusions—

Cardiac iron deposition may be involved in the development of cardiac fibrosis induced by angiotensin II. In addition, iron overload may enhance the formation of neointima under conditions of increased circulating angiotensin II but not catecholamines.