bluuebunny/crossref_metadata_2025 huggingface dataset:
Prejudice toward immigrant workers among Dutch employees: integrated threat theory revisited
Authors: Curşeu Petru Lucian , Stoop Ron , Schalk René
Published: August 2006

Integrated Threat Theory (ITT) (Stephan & Stephan, 1993, 1996) describes four types of threats as mediators in the relation between antecedent factors (previous intergroup conflict, intergroup contact, status inequalities, in‐group identification, knowledge about the out‐group, and intergroup contact) and prejudice. The four mediating types of threats, which influence prejudice according to ITT are: intergroup anxiety, negative stereotyping, realistic and symbolic threats. In this study, the ITT model was tested using structural equation modeling on data collected in sample of 187 Dutch employees. Two alternative explanatory models are proposed in which, first intergroup anxiety and then negative stereotyping mediate the relation between the other ITT threats and prejudice. The data show a good fit with the model in which negative stereotypes are considered as mediator variable. The implications of these findings for ITT are discussed in the context of recent theoretical developments in the study of stereotypes and prejudice. Copyright © 2006 John Wiley & Sons, Ltd.
The impact of perceived experience on likelihood judgments for self and others: an experimental approach
Authors: Harris Peter
Published: August 2006

This study examines the effect of an experimental manipulation of perceived experience on self and others' likelihood ratings for a set of relatively commonplace misfortunes. Participants were randomly assigned to a condition in which they were asked whether they had ever experienced the events (designed to induce higher perceived experience) or whether they had done so frequently, typically, etc. (designed to induce lower perceived experience). The manipulation led to increases in ratings of both perceived self‐likelihood and others' likelihood, in ease of imagining the outcome and recall of a past occurrence, and to decreases in perceived control over the events in the higher perceived experience condition. The increases in ease of imagining mediated the impact of manipulated experience on comparative likelihood whereas the decreases in perceived control did not. There was little evidence that event controllability moderated the impact of experience on comparative likelihood for these events. Copyright © 2006 John Wiley & Sons, Ltd.
No guts, no glory: courage, harassment and minority influence
Authors: Baron Robert S. , Bellman S. Beth
Published: August 2006

To test a courage hypothesis of minority influence, participants read a jury transcript in which a four person majority argued for conviction, while a two person minority argued for acquittal. Across two studies a harassed minority was more persuasive than an un‐harassed minority on both obvious and subtle measures of social influence. In certain cases, these effects occurred only when weak minority arguments were used. In‐group/out‐group status of the minority, manipulated in Study 2, had negligible effects on persuasion. In Study 2, comparisons to a control condition in which all participants argued for acquittal, did not verify the contention that minority influence provokes more careful processing than majority influence despite the fact that harassed minorities were more persuasive on several measures than this type of majority‐control. Copyright © 2006 John Wiley & Sons, Ltd.
Polysemy of traits and judgment of familiar people
Authors: Mollaret Patrick , Mignon Astrid
Published: August 2006

This paper develops a polysemic view of traits labels and outlines the fact that the same label may activate two modes of person perception (1) the agent mode is elicited by behavioural descriptions and emphasizes the role of the actor, and (2) the experiencer mode is elicited by state descriptions and implies an external view of people. The experiment was designed to investigate consequences of mode induction on perception of familiar people. Participants had first to rate traits as behavioural descriptions (agent condition) or as state descriptions (experiencer condition). Then, they had to think about four familiar persons, located at the four poles of the circumplex taxonomy (‘a person they like’, ‘a person they don't like’, ‘a person who has qualities to get on in life’, ‘a person who lacks qualities to get on in life’) and to rate them on a variety of traits scales. Control participants were directly enrolled in the description phase. Results show that, compared to agent induction and control conditions, state induction weakened (1) the evaluative consistency of trait ratings within a dimension (2) the perceived differentiation between people. Consequences of the polysemic conception of traits are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Acrylonitrile‐induced oxidative DNA damage in rat astrocytes
Authors: Pu Xinzhu , Kamendulis Lisa M. , Klaunig James E.
Published: August 2006

Chronic administration of acrylonitrile results in a dose‐related increase in astrocytomas in rat brain, but the mechanism of acrylonitrile carcinogenicity is not fully understood. The potential of acrylonitrile or its metabolites to induce direct DNA damage as a mechanism for acrylonitrile carcinogenicity has been questioned, and recent studies indicate that the mechanism involves the induction of oxidative stress in rat brain. The present study examined the ability of acrylonitrile to induce DNA damage in the DI TNC1 rat astrocyte cell line using the alkaline Comet assay. Oxidized DNA damage also was evaluated using formamidopyrimidine DNA glycosylase treatment in the modified Comet assay. No increase in direct DNA damage was seen in astrocytes exposed to sublethal concentrations of acrylonitrile (0–1.0 mM) for 24 hr. However, acrylonitrile treatment resulted in a concentration‐related increase in oxidative DNA damage after 24 hr. Antioxidant supplementation in the culture media (α‐tocopherol, (−)−epigallocathechin‐3 gallate, or trolox) reduced acrylonitrile‐induced oxidative DNA damage. Depletion of glutathione using 0.1 mM DL‐buthionine‐[S,R]‐sulfoximine increased acrylonitrile‐induced oxidative DNA damage (22–46%), while cotreatment of acrylonitrile with 2.5 mM L‐2‐oxothiazolidine‐4‐carboxylic acid, a precursor for glutathione biosynthesis, significantly reduced acrylonitrile‐induced oxidative DNA damage (7–47%). Cotreatment of acrylonitrile with 0.5 mM 1‐aminobenzotriazole, a suicidal inhibitor of cytochrome P450, prevented the oxidative DNA damage produced by acrylonitrile. Cyanide (0.1–0.5 mM) increased oxidative DNA damage (44–160%) in astrocytes. These studies demonstrate that while acrylonitrile does not directly damage astrocyte DNA, it does increase oxidative DNA damage. The oxidative DNA damage following acrylonitrile exposure appears to arise mainly through the P450 metabolic pathway; moreover, glutathione depletion may contribute to the induction of oxidative DNA damage by acrylonitrile. Environ. Mol. Mutagen., 2006. © 2006 Wiley‐Liss, Inc.
Modeling doline populations with logistic growth functions
Authors: Kemmerly Phillip R.
Published: August 2006

Initiation and evolution of a large karst depression population consisting of parent and daughter dolines were spatially and temporally modeled using logistic growth functions. Logistic growth models are well suited for analyzing doline population initiation and evolution because they reflect the density‐dependent growth mechanisms present in the evolution of karst depressions. Seven assumptions based upon previous studies were refined into mathematical statements and tested using more than 2000 dolines from a subpopulation of both parent and daughter karst depressions on the Western Highland Rim and Pennyroyal Plain of Tennessee and Kentucky. Logistic growth models quantify the initiation and evolution of doline populations and interface well with recent models describing the evolution of three‐dimensional conduit systems. Logistic growth models should apply to modeling other doline populations in karst terranes with hydraulically efficient, three‐dimensional conduit systems. Copyright © 2006 John Wiley & Sons, Ltd.
Organization of hippocampal cell assemblies based on theta phase precession
Authors: Maurer Andrew P. , Cowen Stephen L. , Burke Sara N. , Barnes Carol A. , McNaughton Bruce L.
Published: August 2006

The factors that control the spatial tuning of hippocampal neurons are incompletely understood, and there is no generally agreed upon definition of what constitutes a “place field”. One factor that must be considered is the phenomenon of “phase precession”. As a rat passes through the place field of a particular hippocampal neuron, its spikes shift to earlier phases of the theta rhythm. Except for the special cases discussed herein, the phase shift never exceeds 360°. Moreover, under conditions in which place field sizes change dynamically, precession rate is tightly coupled with the place field size, suggesting that a single cycle of theta phase precession could be used to define unitary place field boundaries. Theta phase precession implies that the “cell assembly” of active hippocampal neurons changes systematically over the course of a single theta cycle. A given cell can exhibit more than one place field in a given environment, each field showing the same pattern of 360° of phase precession. The existence of multiple fields implies that one cell can participate in multiple cell assemblies within the same environment. We show here that place fields, defined as a single cycle of phase precession, can overlap spatially, with the result that the cell fires with spikes clustered at two different phases over the theta cycles in which the fields overlap. Thus, the same neuron can participate in different cell assemblies within a single theta cycle. © 2006 Wiley‐Liss, Inc.
Behavioral correlates of the distributed coding of spatial context
Authors: Anderson Michael I. , Killing Sarah , Morris Caitlin , O'Donoghue Alan , Onyiagha Dikennam , Stevenson Rosemary , Verriotis Madeleine , Jeffery Kathryn J.
Published: August 2006

Hippocampal place cells respond heterogeneously to elemental changes of a compound spatial context, suggesting that they form a distributed code of context, whereby context information is shared across a population of neurons. The question arises as to what this distributed code might be useful for. The present study explored two possibilities: one, that it allows contexts with common elements to be disambiguated, and the other, that it allows a given context to be associated with more than one outcome. We used two naturalistic measures of context processing in rats, rearing and thigmotaxis (boundary‐hugging), to explore how rats responded to contextual novelty and to relate this to the behavior of place cells. In experiment 1, rats showed dishabituation of rearing to a novel reconfiguration of familiar context elements, suggesting that they perceived the reconfiguration as novel, a behavior that parallels that of place cells in a similar situation. In experiment 2, rats were trained in a place preference task on an open‐field arena. A change in the arena context triggered renewed thigmotaxis, and yet navigation continued unimpaired, indicating simultaneous representation of both the altered contextual and constant spatial cues. Place cells similarly exhibited a dual population of responses, consistent with the hypothesis that their activity underlies spatial behavior. Together, these experiments suggest that heterogeneous context encoding (or “partial remapping”) by place cells may function to allow the flexible assignment of associations to contexts, a faculty that could be useful in episodic memory encoding. © 2006 Wiley‐Liss, Inc.
Assessing progressivity of out‐of‐pocket payment: with illustration to Malaysia
Authors: Yu Chai Ping , Whynes David K. , Sach Tracey H.
Published: August 2006

Throughout the world, policy makers are considering or implementing financing strategies that are likely to have a substantial impact on the equity of health financing. The assessment of the equity implication is clearly important, given the potential impact that alternative finance sources have on households. Households incur out‐of‐pocket payment directly from their budget, apart from their public or private insurance. Out‐of‐pocket payment is the primary concern, given their undesirable impact on households. Progressivity measures departures from proportionality in the relationship between out‐of‐pocket payment and ability to pay. It is the most frequently used yardstick to assess the equity of out‐of‐pocket payments in empirical studies. This paper provides an evaluation of such progressivity measures, undertaken using four approaches (proportion approach, tabulation approach, concentration curve and Kakwani's index), in order to reveal their usefulness and underlying notion. It is illustrated empirically with data on out‐of‐pocket payment for health care in Malaysia for 1998/1999, based on the nationally representative Household Expenditure Survey. Results indicate that out‐of‐pocket payments are mildly progressive, whilst the four approaches have their benefits and limitations in assessing equity implications. This analysis is of interest from a policy perspective, given Malaysia's heavy reliance on out‐of‐pocket payments to finance health care. Copyright © 2006 John Wiley & Sons, Ltd.
Long‐term patient monitoring for clozapine‐induced agranulocytosis and neutropenia in Korea: when is it safe to discontinue CPMS?
Authors: Kang Byung‐Jo , Cho Man‐Je , Oh Jung‐Tae , Lee Yanghyun , Chae Beang‐Jin , Ko Jaewook
Published: August 2006

Objectives

This study documents the incidences of agranulocytosis and neutropenia, and the patterns of incidence of the side effects of long‐term clozapine treatment in order to determine an appropriate time to stop the Clozaril Patient Monitoring System (CPMS).

Methods

Hematological, demographic, and other data from the CPMS for 6782 patients who took clozapine for the past 11 years in the Republic of Korea has been analyzed.

Results

Twenty‐nine (53.7%) of fifty‐four agranulocytosis cases occurred within the first 18 weeks. The cumulative incidence of agranulocytosis was 1.64% between 6 and 11 years and the crude incidence was 0.8%. Neutropenia occurred in 697 patients, and 365 (52.4%) of these cases occurred within the first 18 weeks. The cumulative incidence of neutropenia was 19.8% between 8 and 11 years, and the crude incidence was 10.3%. There were no cases of agranulocytosis or neutropenia after the 9th year of clozapine treatment.

Conclusions

The incidence of agranulocytosis in the Republic of Korea was similar to those in the rest of the world. While agranulocytosis began several years after clozapine treatment, long‐term monitoring of white blood cells is necessary. We suggest that the CPMS should be stopped or less frequently after the 9th year of treatment. Copyright © 2006 John Wiley & Sons, Ltd.
The expression of metastasis suppressor MIM/MTSS1 is regulated by DNA methylation
Authors: Utikal Jochen , Gratchev Alexei , Muller‐Molinet Isabelle , Oerther Sandra , Kzhyshkowska Julia , Arens Norbert , Grobholz Rainer , Kannookadan Sheila , Goerdt Sergij
Published: August 2006

MIM/MTSS1 was initially described as a gene missing in invasive bladder cancer cell lines. Functional analysis revealed that MIM is an actin binding protein involved in the regulation of actin cytoskeleton dynamics. MIM was shown to be sonic hedgehog (Shh) signaling dependent and synergizes with the effects of Gli transcription factors. Overexpression of MIM in cell lines leads to the inhibition of cell proliferation. In this study, we showed that the inhibition of cell growth by MIM is anchorage independent. We identified and cloned the promoter region of MIM and located the main promoter activity to 276 bp of 5′ flanking sequence sited within a CpG island. Analysis of DNA methylation using bisulphite sequencing revealed that MIM promoter is methylated in its 5′ region in cells and tissue samples with reduced endogenous MIM expression. Using luciferase reporter assay, we demonstrated that nonmethylated MIM promoter has a similar activity in cell lines with different endogenous MIM expression. Inhibition of DNA methylation by 5‐Aza‐2′‐deoxycytidine led to upregulation of MIM expression in a low expressing cell line. In conclusion, we clearly demonstrate here that the expression of metastasis suppressor MIM is regulated by DNA methylation of a CpG island within its promoter region. © 2006 Wiley‐Liss, Inc.
Microvascular endothelial cells increase proliferation and inhibit apoptosis of native human acute myelogenous leukemia blasts
Authors: Hatfield Kimberley , Ryningen Anita , Corbascio Matthias , Bruserud Øystein
Published: August 2006

Interactions between acute myelogenous leukemia (AML) blasts and neighbouring endothelial cells in the bone marrow seem important both for disease development and susceptibility to chemotherapy. We investigated the effects of soluble mediators released by microvascular endothelial cells on native human AML cells. AML cells derived from 33 patients were cocultured with microvascular endothelial cells, separated by a semipermeable membrane. We investigated the effect of coculture on AML cell proliferation, viability/apoptosis and cytokine release. Coculture increased AML cell proliferation, and this growth enhancement included the clonogenic leukemia cell subset. Increased release of several soluble mediators was also detected (interleukin 3, interleukin 6, granulocyte‐macrophage and granulocyte colony‐stimulating factors) in cocultures. Our cytokine neutralization experiments suggest that an intercellular crosstalk involving several soluble mediators contribute to the increased leukemia cell proliferation. The presence of endothelial cells had an additional antiapoptotic effect on the AML cells. The endothelial cells did not have any growth‐enhancing effect on native human acute lymphoblastic leukemia cells. Our in vitro results suggest that the release of soluble mediators by microvascular endothelial cells supports leukemic hematopoiesis through paracrine mechanisms by direct enhancement of AML blast proliferation and by inhibition of leukemic cell apoptosis. © 2006 Wiley‐Liss, Inc.
Dose‐dependent effect of low‐intensity pulsed ultrasound on callus formation during rapid distraction osteogenesis
Authors: Chan Chun Wai , Qin Ling , Lee Kwong Man , Cheung Wing Hoi , Cheng Jack Chun Yiu , Leung Kwok Sui
Published: August 2006

Distraction osteogenesis of bone or callotasis causes poor bone formation when the distraction rate is beyond the optimal rate. Low‐intensity pulsed ultrasound was reported to enhance fracture healing, treatment of nonunion, and accelerate bone maturation and remodeling during consolidation stage of distraction osteogenesis. In this study, we evaluated the efficacy of different durations of LIPUS treatments during rapid bone lengthening. After 7‐day latent period, osteotomized New Zealand white rabbit tibiae were lengthened at the rate of 2 mm per day for 1 week. Two different LIPUS treatment durations of 20 min and 40 min were selected for treatment groups. Rabbits without treatment served as the control group. Plain X‐ray, peripheral quantitative computed tomography (pQCT) and histology were performed to assess bone acquisition in the distraction callus. The results showed that LIPUS increased bone mineral content and volume of the mineralized tissue of distraction callus in a dose‐dependent manner. The different regions of distraction callus exhibited various spatial response to LIPUS treatment. Moreover, LIPUS enhanced dose‐dependant endochondral formation. Compared with 20‐min treatment, the 40‐min LIPUS treatment was a more favorable treatment duration for bone regeneration in the distraction callus. In conclusion, LIPUS was able to enhance bone regeneration under rapid distraction, and its effect was dose‐dependent. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:2072–2079, 2006
Impact of liming on utilization of 59Fe‐chelates by lettuce (Lactuca sativa L.)
Authors: Ylivainio Kari , Jaakkola Antti , Aksela Reijo
Published: August 2006

A pot experiment was conducted to determine the utilization of iron (Fe) by lettuce (Lactuca sativa L. cv. Australian gelber). Iron was applied as 59Fe in inorganic and chelated form, particularly biodegradable chelate, 59Fe‐EDDS. Two stereoisomeric forms of ethylenediaminedisuccinate: [S,S]‐EDDS and a mixture of EDDS containing 25% [S,S]‐EDDS, 25% [R,R]‐EDDS, and 50% [S/R]/[R/S]‐EDDS, ethylenediaminetetraaceticacid (EDTA) and ethylenediimino bis(2‐hydroxyphenyl)acetic acid (EDDHA) were used as ligands. Lettuce was grown in unlimed and limed quartz sand with nitrate as the sole source of nitrogen. Liming decreased lettuce yields but had no effect on Fe concentrations, indicating that Fe concentrations were a poor indicator of Fe bioavailability within the plant. In unlimed sand, utilization of 59Fe from all 59Fe‐chelates was on the same level (2.8%–3.6%). In limed sand, only 59Fe‐EDDHA maintained the 59Fe utilization on a level (3%) comparable to that in unlimed sand. Although the utilization of 59Fe from the other chelates decreased to 0.6%–1.1% after liming, Fe concentrations were not affected due to the increased uptake of indigenous Fe. The most biodegradable form of EDDS, namely 59Fe‐EDDS(S,S), provided 59Fe for lettuce as efficiently as the mixture of 59Fe‐EDDS stereoisomers and the 59Fe‐EDTA. Utilization of 59Fe in inorganic form was 0.5% and 0.03% in unlimed and limed sand, respectively. This study shows that biodegradable ligands are able to serve as chelators to sustain Fe availability in calcareous environments. They may be of use especially in drip irrigation, where ligand accumulations may pose a threat to groundwater quality.
Microbial C, N, and P relationships in moisture‐stressed soils of Potohar, Pakistan
Authors: Khan Khalid Saifullah , Joergensen Rainer Georg
Published: August 2006

In 11 rain‐fed arable soils of the Potohar plateau, Pakistan, the amounts of microbial‐biomass C (Cmic), biomass N (Nmic), and biomass P (Pmic) were analyzed in relation to the element‐specific total storage compartment, i.e., soil Corg, Nt, and Pt. The effects of climatic conditions and soil physico‐chemical properties on these relationships were highlighted with special respect to crop yield levels. Average contents of soil Corg, Nt, and Pt were 3.9, 0.32, and 0.61 mg (g soil)–1, respectively. Less than 1% of Pt was extractable with 0.5 M NaHCO3. Mean contents of Cmic, Nmic, and Pmic were 118.4, 12.0, and 3.9 µg (g soil)–1. Values of Cmic, Nmic, Pmic, soil Corg, and Nt were all highly significantly interrelated. The mean crop yield level was closely connected with all soil organic matter– and microbial biomass–related properties, but showed also some influence by the amount of precipitation from September to June. Also the fraction of NaHCO3‐extractable P was closely related to soil organic matter, soil microbial biomass, and crop yield level. This reveals the overwhelming importance of biological processes for P turnover in alkaline soils.
Clonal and seasonal shifts in communities of saprotrophic microfungi and soil enzyme activities in the mycorrhizosphere of Salix spp.
Authors: Baum Christel , Hrynkiewicz Katarzyna
Published: August 2006

The species‐specific microbial root and rhizosphere colonization contributes essentially to the plant nutrient supply. The species number and colonization densities of cultivable saprotrophic microfungi and the activities of nutrient‐releasing soil enzymes (protease, acid and alkaline phosphatase, arylsulfatase) were investigated in the rhizosphere of one low mycorrhizal (Salix viminalis) and one higher mycorrhizal (S. × dasyclados) willow clone at a Eutric Cambisol in N Germany. After soil washing, in total 32 and 28 saprotrophic microfungal species were isolated and identified microscopically from the rhizosphere of S. viminalis and S. × dasyclados, respectively. The fungal species composition changed within the growing season but the species number was always lower under S. × dasyclados than under S. viminalis. Under both willow clones, the fungal colonization density was largest in spring, and the species number was largest in autumn. Acid‐phosphatase activity (p < 0.001) and protease activity (p < 0.003) were significantly affected by the Salix clone, whereas arylsulfatase and alkaline‐phosphatase activities did not show clone‐specific differences. All enzyme activities reached their maxima in the summer sampling. Rhizosphere colonization with Acremonium butyri, Cladosporium herbarum, and Penicillium janthinellum contributed significantly to explain the activities of acid phosphatase. Rhizosphere colonization with Cylindrocarpon destructans, Penicillium spinulosum, Plectosphaerella cucumerina, and Trichoderma polysporum contributed significantly to explain the arylsulfatase activities. Effects of the saprotrophic fungal colonization densities on the protease activities in the rhizosphere were low. Acid‐ and alkaline‐phosphatase and arylsulfatase activities in the rhizosphere soil were stronger affected by the composition of the saprotrophic fungal communities than by the Salix clone itself. In conclusion, the colonization density of some saprotrophic microfungi in the rhizosphere contributed to explain shifts in soil‐enzyme activities of the P and S cycles under different willow clones.
Heavy‐metal mobilization and uptake by mycorrhizal and nonmycorrhizal willows (Salix × dasyclados)
Authors: Baum Christel , Hrynkiewicz Katarzyna , Leinweber Peter , Meißner Ralph
Published: August 2006

Ectomycorrhizal fungi have been shown to affect metal transfer from the soil to the host plant, but the use of these fungi for increased phytoextraction of heavy metals has been scarcely investigated. Therefore, a two‐factorial pot experiment was conducted with Salix × dasyclados and (1) two contaminated soils with different concentrations of NH4NO3‐extractable metals and (2) two strains of the ectomycorrhizal fungus Paxillus involutus (one strain originating from a noncontaminated site—Pax1, and another from a contaminated site—Pax2). The inoculation with Pax2 increased the phytoavailability of Cd in the soils. Inoculation with both fungal strains increased the stem and root biomass, but had no effect on metal concentrations in the stems. Decreased Cd and increased Cu concentrations were observed in the roots of inoculated willows. The inoculation with P. involutus increased Cd (up to 22%), Zn (up to 48%), and Cu content in the stems. Decreased Pb content (Cu and Pb content were always <1 mg per plant) occurred in the stems from plants at the soil with the higher concentration of NH4NO3‐extractable metals. Contrary to this, in the soil with lower concentrations of NH4NO3‐extractable metals, the inoculation had no significant effects on the total uptake of Zn and Cu and even caused decreased Cd (Pax2) and Pb (Pax1) contents in the stems. Strain Pax2 had higher colonization densities, but the plants had lower mycorrhizal dependencies in the contaminated soils than after inoculation with the strain Pax1. Generally, metal extractability in the soils substantially affected the mycorrhizal dependency and heavy‐metal uptake of the willows. We concluded, that the inoculation with P. involutus offers an opportunity to particularly increase the phytoextraction of Zn, but the metal extractability and fungal strain effects have to be tested.
Silicon pools and fluxes in soils and landscapes—a review
Authors: Sommer Michael , Kaczorek Danuta , Kuzyakov Yakov , Breuer Jörn
Published: August 2006

Silicon (Si) is the second‐most abundant element in the earth's crust. In the pedosphere, however, huge spans of Si contents occur mainly caused by Si redistribution in soil profiles and landscapes. Here, we summarize the current knowledge on the different pools and fluxes of Si in soils and terrestrial biogeosystems. Weathering and subsequent release of soluble Si may lead to (1) secondarily bound Si in newly formed Al silicates, (2) amorphous silica precipitation on surfaces of other minerals, (3) plant uptake, formation of phytogenic Si, and subsequent retranslocation to soils, (4) translocation within soil profiles and formation of new horizons, or (5) translocation out of soils (desilication). The research carried out hitherto focused on the participation of Si in weathering processes, especially in clay neoformation, buffering mechanisms for acids in soils or chemical denudation of landscapes. There are, however, only few investigations on the characteristics and controls of the low‐crystalline, almost pure silica compounds formed during pedogenesis. Further, there is strong demand to improve the knowledge of (micro)biological and rhizosphere processes contributing to Si mobilization, plant uptake, and formation of phytogenic Si in plants, and release due to microbial decomposition. The contribution of the biogenic Si sources to Si redistribution within soil profiles and desilication remains unknown concerning the pools, rates, processes, and driving forces. Comprehensive studies considering soil hydrological, chemical, and biological processes as well as their interactions at the scale of pedons and landscapes are necessary to make up and model the Si balance and to couple terrestrial processes with Si cycle of limnic, fluvial, or marine biogeosystems.
Observations on the presence of E domain variants of estrogen receptor‐α in the breast tumors
Authors: Kumar Vijay L. , Kumar Suresh , Srivastava Anurag , Kumar Vijay
Published: August 2006

Background and Objectives

Estrogen receptor‐α (ER‐α) that exists as multiple splice variants, has been widely used as a prognostic marker in the management of breast cancer. Here we have analyzed the hormone binding E domain splice variants of ER‐α in the breast tumors with reference to the immunoreactive receptor.

Methods

Thirty breast cancer patients undergoing surgery at the All India Institute of Medical Sciences, New Delhi, were analyzed for the splice variants of E domain by RT‐PCR. The ER level was determined by ELISA and the samples were considered positive if the receptor levels were ≥ 15 fmol/mg protein.

Results

Our results show that exon 4 and 5 deletions were prevalent in both ER‐positive and ER‐negative categories. While most ER‐positive cases expressed wild‐type (wt) exon 6 + 7, nearly 40% of ER‐negative cases showed deletion of exon 6 + 7. Therefore, deletion of exon 6 + 7 or masking of epitopes could lead to underestimation of ER by ELISA. All the metastasis and recurrence cases had undetectable levels of ER. A significant number of node‐positive cases expressed immunoreactive ER and wt exon 6 + 7 (r = 0.509, P < 0.37).

Conclusions

Estimation of ER levels combined with composite analysis of ER variants may be a better prognostic marker for breast cancer. J. Surg. Oncol. 2006;94:332–337. © 2006 Wiley‐Liss, Inc
One‐Pot Synthesis of an Alternating Copolyimide Based on Regioselective Reaction of a Non‐Symmetrical Alicyclic Dianhydride
Authors: Kudo Kazuaki , Yoshizawa Takuya , Hamada Takashi , Li Jun , Sakamoto Seiji , Shiraishi Shinsaku
Published: August 2006

Summary: Four constitutionally isomeric copoly(amide acid)s (coPAAs), two alternating and two random, have been successfully obtained from the same combination of one non‐symmetrical alicyclic tetracarboxylic dianhydride (1.0 molar equivalents) and two symmetric aromatic diamines (0.5 molar equivalents each) by only slightly changing the reaction procedures. When the reaction mixture is subjected to chemical imidization conditions without isolation of coPAAs, the corresponding copolyimides (coPIs) are obtained in one pot. All of the coPIs are slightly yellow amorphous powders and the solubility of them is similar to each other. The glass transition temperatures of the alternating coPIs are lower in comparison to those of the random coPIs.

Schematic of the possible arrangement of monomers in the copoly(amide acid)s/copolyimides synthesized here.

magnified image

Schematic of the possible arrangement of monomers in the copoly(amide acid)s/copolyimides synthesized here.
Dual action on promoter demethylation and chromatin by an isothiocyanate restored GSTP1 silenced in prostate cancer
Authors: Wang L. G. , Beklemisheva A. , Liu X. M. , Ferrari A. C. , Feng J. , Chiao J. W.
Published: August 2006

Prostate carcinoma is characterized by the silencing of π‐class glutathione S‐transferase gene (GSTP1), which encodes a detoxifying enzyme. The silencing of GSTP1, due to aberrant methylation at the CpG island in the promoter/5′‐UTR, occurs in the vast majority of prostate tumors and precancerous lesions. It is a pathologic marker and probably an underlying cause of oxidative damage and inflammation at tumor initiation. Inhibition of the aberrant promoter methylation could therefore be an effective mean to prevent carcinogenesis. Several isothiocyanates, including phenethyl isothiocyanate (PEITC), found naturally in cruciferous vegetables, induced growth arrest and apoptosis in prostate cancer cells in culture and xenografts. The effects of PEITC to reactivate GSTP1 were investigated. Exposure of prostate cancer LNCaP cells to PEITC inhibited the activity and level of histone deacetylases (HDACs), and induced selective histone acetylation and methylation for chromatin unfolding. Concurrently PEITC demethylated the promoter and restored the unmethylated GSTP1 in both androgen‐dependent and ‐independent LNCaP cancer cells to the level found in normal prostatic cells, as quantified by methylation‐specific PCR and pyrosequencing. The dual action of PEITC on both the DNA and chromatin was more effective than 5′‐Aza‐2′‐deoxycytidine, sodium butyrate, or trichostatin A (TSA), and may de‐repress the methyl‐binding domain (MBD) on gene transcription. The PEITC‐mediated cross‐talk between the DNA and chromatin in demethylating and reactivating GSTP1 genes, which is critically inactivated in prostate carcinogenesis, underlines a primary mechanism of cancer chemoprevention. Consequently, new approaches could be developed, with isothiocyanates to prevent and inhibit malignancies. © 2006 Wiley‐Liss, Inc.
A new approximation for pore pressure accumulation in marine sediment due to water waves
Authors: Jeng D.‐S. , Seymour B. R. , Li J.
Published: August 2006

The residual mechanism of wave‐induced pore water pressure accumulation in marine sediments is re‐examined. An analytical approximation is derived using a linear relation for pore pressure generation in cyclic loading, and mistakes in previous solutions (Int. J. Numer. Anal. Methods Geomech. 2001; 25:885–907; J. Offshore Mech. Arctic Eng. (ASME) 1989; 111(1):1–11) are corrected. A numerical scheme is then employed to solve the case with a non‐linear relation for pore pressure generation. Both analytical and numerical solutions are verified with experimental data (Laboratory and field investigation of wave–
sediment interaction. Joseph H. Defrees Hydraulics Laboratory, School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, 1983), and provide a better prediction of pore pressure accumulation than the previous solution (J. Offshore Mech. Arctic Eng. (ASME) 1989; 111(1):1–11). The parametric study concludes that the pore pressure accumulation and use of full non‐linear relation of pore pressure become more important under the following conditions: (1) large wave amplitude, (2) longer wave period, (3) shallow water, (4) shallow soil and (5) softer soils with a low consolidation coefficient. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of selective unilateral dorsal root(s) rhizotomy on micturition reflex in anesthetized rats
Authors: Tsai Ming‐Cheng , Tang Chih‐Yung , Chang Ya‐Ting , Cheng Chen‐Li , Liao Jiuan‐Miaw , Lee Shin‐Da , Pan Shwu‐Fen , Chen Mei‐Jung , Huang Pei‐Chen , Lin Tzer‐Bin
Published: August 2006

Purpose:

To clarify the contributions of sensory inputs and glutamate transmissions to the spinal micturition reflex.

Materials and Methods:

Cystometrogram and external urethral sphincter electromyogram activities evaluated the L6 and/or S1 levels.

Results:

Changes in intravesicular pressure (IVP) in response to saline infusion (0.1 ml/min) were found after unilateral dorsal root rhizotomy at the L6 level, which showed significant increases in threshold pressure (rhizotomized vs. control: 14.25 ± 0.82 vs. 8.40 ± 0.69 cmH2O,P < 0.01, n = 28), post‐voiding pressure (7.66 ± 0.56 vs. 5.42 ± 0.52 cmH2O,P < 0.01, n = 28), holding duration (135.06 ± 23.6 vs. 77.73 ± 13.56 sec,P < 0.05, n = 28), and inter‐contraction interval (140.62 ± 23.29 vs. 82.40 ± 13.57 sec,P < 0.05, n = 28). Several (mean = 2.32 ± 1.31 vs. 0.12 ± 0.21,P < 0.01, n = 28,P < 0.01, n = 28) non‐voiding contractions with gradual increase in IVP were found ahead of voiding contraction after rhizotomy. An additional dorsal root rhizotomy at the ipsilateral S1 level caused further increases in urodynamic parameters (threshold pressure, 18.18 ± 1.67 cmH2O,P < 0.01; post‐voiding pressure 8.07 ± 0.96 cmH2O,P < 0.01; holding duration, 211.44 ± 42.54 sec,P < 0.01; inter‐contraction interval, 264.2 ± 59.99 sec,P < 0.05; non‐voiding contractions, 4.41 ± 2.12,P < 0.01, n = 7). Intrathecal glutamate (100 µM, 10 µl) ameliorated all the pathological conditions induced by unilateral dorsal root rhizotomy at the L6 level in a dose dependent manner (ED50 = 1.25 ± 10−5). Intrathecal CNQX (6‐cyano‐7‐nitroquinoxaline‐2,3‐dione; 100 µM, 10 µl) and APV (D‐2‐amino‐5‐phosphonovaleric acid; 100 µM, 10 µl) injections after rhizotomy at the L6 level induced disturbances similar to that caused by an additional rhizotomy at ipsilateral S1 level. Wherease, glutamate (100 µM, 10 µl) reversed the disturbances caused by CNQX but showed no effect on that by APV.

Conclusions:

Acute partial sensory deprivation caused acute impaired micturition reflex in rat models. In addition, glutamatergic NMDA and AMPA receptors are important for mediating these impairments in micturition reflex. Neurourol. Urodynam. 25:820–827, 2006. © 2006 Wiley‐Liss, Inc.
Wirkungs‐ und Resistenzmechanismen der β‐Lactam‐Antibiotika: Penicillin‐bindende Proteine, β‐Lactamasen und Signalproteine
Authors: Heisig Peter
Published: August 2006

Mechanistisch lassen sich drei Wege der Resistenzentwicklung gegen β‐Lactam‐Antibiotika unterscheiden, die teilweise allein, teilweise aber auch in Kombination zur Entwicklung von klinisch relevanter Resistenz geführt haben: die Reduktion der Antibiotikakonzentration an der Zielstruktur, die Produktion inaktivierender Enzyme und die Bildung modifizierter Zielstrukturen.
β‐Lactamasen: Ein Gegner, der nicht besiegt werden kann
Authors: Theuretzbacher Ursula
Published: August 2006

Die Bildung von β‐Lactamasen ist der häufigste Resistenzmechanismus bei β‐Lactam‐Antibiotika. Nicht nur neue β‐Lactamasen, sondern vor allem Effizienzsteigerung der schon lange bekannten Enzyme, die Kombination verschiedener Resistenzmechanismen und die erleichterte Übertragbarkeit gemeinsam mit anderen Resistenzen durch mobile genetische Elemente gewährleisten diesem Thema eine fortdauernde Aktualität.
Methicillin‐resistenter Staphylococcus aureus: β‐Lactam‐Resistenz “trifft” Virulenz
Authors: Linde Hans‐Jörg , Lehn Norbert
Published: August 2006

CA‐MRSA sind weltweit ein emerging pathogen außerhalb von medizinischen Einrichtungen. Sie betreffen Patienten ohne Risikofaktoren, insbesondere auch Kinder und Erwachsene im jüngeren Alter. Typischerweise kommt es zu Haut‐ und Weichteilinfektionen, die häufig mit Komplikationen verlaufen (multipel, rezidivierend, seltener Endokarditis, Osteomyelitis, septische Arthritis). Seltene schwere Komplikationen sind nekrotisierende Pneumonien, nekrotisierende Fasziitis, Purpura fulminans und Waterhouse‐Friderichsen‐Syndrom. Als besonderen Virulenzfaktor weisen CA‐MRSA u.a. das Panton‐Valentine‐Leukozidin auf. Die Stämme sind resistent gegen alle β‐Lactam‐Antibiotika. Zur Therapie sind Clindamycin, Doxycyclin, Moxifloxacin, Co‐Trimoxazol, Linezolid, Glykopeptide und Daptomycin geeignet. Die Sanierung des Trägerstatus ist aufwändig und verlangt eine sorgfältige Planung. Um eine weitere Verbreitung zu verhindern, sind verbesserte diagnostische, therapeutische und hygienische Maßnahmen bei niedergelassenen Ärzten und in Krankenhäusern nötig.
Unerwünschte Wirkungen der β‐Lactam‐Antibiotika: Widerspruch zu Ehrlichs Paradigma der selektiven Toxizität
Authors: Sendzik Judith , Stahlmann Ralf
Published: August 2006

Trotz der unerwünschten Wirkungen der β‐Lactam‐Antibiotika insbesondere auf das gastrointestinale System und in Form von Überempfindlichkeitsreaktionen, sind die Vertreter dieser Substanzklasse als gut verträgliche antibakterielle Therapeutika anzusehen. Dies wird auch durch den weit verbreiteten Einsatz in der Pädiatrie unterstrichen. Ein rationaler Einsatz der β‐Lactam‐Antibiotika und die Möglichkeit eine Überempfindlichkeit auf diese Arzneimittelgruppe mit Hilfe von genauer Anamnese, Hauttests und Blutanalysen einzugrenzen, kann die Risiken einer β‐Lactam‐Therapie minimieren.
Pharmakokinetik und Pharmakodynamik der β‐Lactame: Was wir über β‐Lactame wissen und was wir wissen möchten
Authors: Sörgel Fritz , Bulitta Jürgen , Landersdorfer Cornelia
Published: August 2006

Durch die Entwicklung der β‐Lactame wurde schon früh die Bedeutung von Pharmakokinetik deutlich. Neue hochspezifische Analysemethoden wie die LC‐MS/MS haben das Studium der Pharmakokinetik von β‐Lactamen und ihren Metaboliten sehr vorangebracht. LC‐MS/MS und Mikrodialyse sind viel versprechende Methoden zur Bestimmung der Gewebepenetration von β‐Lactamen. Kleine chemische Veränderungen an β‐Lactam‐Molekülen brachten teilweise bedeutende Verbesserungen der Pharmakokinetik und Wirksamkeit. β‐Lactame sind Substrate von Transportern, was nicht nur im Magen‐Darm‐Trakt und in der Niere wichtig ist. Obwohl β‐Lactame ein Eckpfeiler in der Antibiotika‐Therapie sind, gibt es auch heute noch viele offene Fragen. Wir brauchen mehr Studien zur Pharmakokinetik und Pharmakodynamik im Menschen, insbesondere in schwerkranken Patienten. Populationspharmakokinetische Modelle und Monte‐Carlo‐Simulationen sollten die Grundlage sein, um das Studiendesign neuer großer Wirksamkeitsstudien zu optimieren. Als eine der wichtigsten Fragen sollte die mögliche Überlegenheit von kontinuierlicher oder verlängerter Infusion gegenüber Kurzzeitinfusion untersucht werden.
Neue Waffe gegen β‐Lactamasen?
Authors: Bennack Edith , Holzgrabe Ulrike
Published: August 2006

Gegen die beste Waffe Gram‐negativer Bakterien gegen β‐Lactam‐Antibiotika, die β‐Lactamasen, war bisher kein Suizid‐Inhibitor uneingeschränkt erfolgreich. Während sich β‐Lactamasen vom Serin‐Protease‐Typ, der weitaus größeren Gruppe der β‐Lactamasen, wenigstens mittels Clavulansäure, Sulbactam und Tazobactam hemmen ließen, so können diese, aber auch Carbapenem und Imipenem, die Lactam‐Hydrolyse durch die Metallo‐β‐Lactamasen nicht mehr verhindern.
Papillary thyroid carcinoma in a 9‐year‐old girl with ataxia‐telangiectasia
Authors: Brasseur Benoit , Beauloye Véronique , Chantrain Christophe , Daumerie Chantal , Vermylen Christiane , Waignein Frédéric , Brichard Bénédicte
Published: August 2006

A 9‐year‐old female with ataxia‐telangiectasia (AT) presenting with papillary thyroid carcinoma and lymph nodes involvement is reported. We discuss this novel association, the general risk of neoplasic complications in these patients, the natural history of thyroid carcinoma in the pediatric population and the potential link between thyroid carcinogenesis and ataxia‐telangiectasia mutated gene (ATM) mutation. We also expose our therapeutic attitude, according to both clinical status and particular genetic background of our patient. Pediatr Blood Cancer 2008;50:1058–1060. © 2006 Wiley‐Liss, Inc.
Promoter hypermethylation of the RASSF1A gene predicts the poor outcome of patients with hepatoblastoma
Authors: Sugawara Waka , Haruta Masayuki , Sasaki Fumiaki , Watanabe Naoki , Tsunematsu Yukiko , Kikuta Atsushi , Kaneko Yasuhiko
Published: August 2006

Background

Despite the progress of therapy, about 25% of patients with hepatoblastoma succumb to the disease. Prognostic factors, as well as improved therapies, are needed for these patients. We investigated the incidence and clinical significance of genetic and epigenetic aberrations in hepatoblastoma.

Procedure

β‐catenin mutation was analyzed by sequencing and promoter hypermethylation of the RASSF1A and SFRP genes by methylation‐specific PCR after bisulfate treatment of DNA samples from 39 hepatoblastomas. Association of the clinical and biological features, including sex, age of patients, stage of the disease, the histological type, and the β‐catenin and RASSF1A status with overall survival was evaluated using univariate and multivariate analysis.

Results

β‐catenin mutation and RASSF1A methylation were found in 22 (56.4%) and 15 (38.5%) of 39 hepatoblastomas, respectively, but SFRPs methylation was not found in any of them. RASSF1A and SFRPs were unmethylated in five adjacent normal liver tissues. Patients with a RASSF1A methylated tumor were older in age (≥2 years, P = 0.036), at more advanced stages (P = 0.009), and had more frequent β‐catenin mutation (P < 0.001) and poorer outcome (P < 0.001) than those with a RASSF1A unmethylated tumor. While univariate analysis showed the prognostic significance of age, stage, the histological type, and the β‐catenin and RASSF1A status, multivariate analysis showed only the RASSF1A methylation status as an independent factor predicting outcome (relative risk, 10.51; 95% CI, 1.21 ∼ 90.97; P = 0.033).

Conclusions

RASSF1A methylation may be a novel molecular‐genetic marker for treatment outcome in hepatoblastoma if confirmed by studies examining a larger number of hepatoblastomas. Pediatr Blood Cancer. Pediatr Blood Cancer 2007;49:240–249. © 2006 Wiley‐Liss, Inc.
Mental health and other clinical correlates of euthanasia attitudes in an Australian outpatient cancer population
Authors: Carter G. L. , Clover K. A. , Parkinson L. , Rainbird K. , Kerridge I. , Ravenscroft P. , Cavenagh J. , McPhee J.
Published: August 2006

A majority of patients with cancer have been reported to endorse euthanasia and physician assisted suicide (PAS) in general and a substantial proportion endorse these for themselves. However, the potential influence of mental health and other clinical variables on these decisions is not well understood. This study of 228 outpatients attending an oncology clinic in Newcastle, Australia used a cross‐sectional design and logistic regression modelling to examine the relationship of demographic, disease status, mental health and quality of life variables to attitudes toward euthanasia and PAS. The majority reported support for euthanasia (79%, n=179), for PAS (69%, n=158) and personal support for euthanasia/PAS (68%, n=156). However, few reported having asked their doctor for euthanasia (2%, n=5) or PAS (2%, n=5). Three outcomes were modelled: support for euthanasia was associated with active religious belief (adjusted odds ratio (AOR) 0.21, 95% CI: 0.10–0.46); support for PAS was associated with active religious belief (AOR 0.35, 95% CI: 18–0.70) and recent pain (AOR 0.87, 95% CI: 0.0.76–0.99); and personal support for euthanasia/PAS was associated with active religious belief (AOR 0.26, 95% CI: 0.14–0.48). Depression, anxiety, recent suicidal ideation, and lifetime suicide attempt were not independently associated with any of the three outcomes modelled. Copyright © 2006 John Wiley & Sons, Ltd.