bluuebunny/crossref_metadata_2025 huggingface dataset:
The Midwife of Platonism
Authors: Sedley David
Published: March 2005

Plato’s Theaetetus is thought to have been written after his main middle-period dialogues, in which he expounded his celebrated metaphysical doctrine of Forms. Yet, it is an open-ended Socratic dialogue and investigates the question ‘What is knowledge?’ without positive result, and with an unexpected restraint about invoking the metaphysical theory. Why? This book develops a new solution to the old question. Plato wants to demonstrate the continuity of his mature work with that of his master Socrates and does so by invoking the now famous image, unique to this dialogue, of Socrates as the barren midwife of others’ brainchildren. The message is that Socrates, although not himself a Platonist, was the midwife of Platonism. This is brought out by portraying a Socrates who, rather than Plato’s current spokesman, is a throwback to the semi-historical figure immortalized in the early dialogues. We see this Socrates, in the course of his characteristic dialectical investigations, pointing us to recognizably Platonic solutions, but himself unable to articulate them that way because of his lack of a Platonic metaphysics. In addition to linking Plato’s Socratic past to his Platonic present, the same device also points forward to Plato’s future work in such dialogues as Sophist and Timaeus.
Tissue-Specific Localization of Pea Root Infection by Nectria haematococca. Mechanisms and Consequences
Authors: Gunawardena Uvini , Rodriguez Marianela , Straney David , Romeo John T. , VanEtten Hans D. , Hawes Martha C.
Published: March 2005

Root infection in susceptible host species is initiated predominantly in the zone of elongation, whereas the remainder of the root is resistant. Nectria haematococca infection of pea (Pisum sativum) was used as a model to explore possible mechanisms influencing the localization of root infection. The failure to infect the root tip was not due to a failure to induce spore germination at this site, suppression of pathogenicity genes in the fungus, or increased expression of plant defense genes. Instead, exudates from the root tip induce rapid spore germination by a pathway that is independent of nutrient-induced germination. Subsequently, a factor produced during fungal infection and death of border cells at the root apex appears to selectively suppress fungal growth and prevent sporulation. Host-specific mantle formation in response to border cells appears to represent a previously unrecognized form of host-parasite relationship common to diverse species. The dynamics of signal exchange leading to mantle development may play a key role in fostering plant health, by protecting root meristems from pathogenic invasion.
Contraction induced by glicentin on smooth muscle cells from the human colon is abolished by exendin (9–39)
Authors: Ayachi S. E. , Borie F. , Magous R. , Sasaki K. , Le Nguyen D. , Bali J.‐p. , Millat B. , Jarrousse C.
Published: March 2005

Abstract  Glicentin and glucagon‐like peptide‐1 (7–36) amide (GLP‐1) are gut hormones released during digestion. Glicentin and GLP‐1 slow down gastric emptying and glicentin can switch off the duodenojejunal fed motor pattern. The effect of glicentin on the motor activity of colon has never been reported in humans. Our aim was to determine if circular smooth muscle cells (SMC) from the human colon are target cells for glicentin or GLP‐1, and if their motility is dependent upon these digestive hormones. Methods: Twenty‐two resections were performed on patients operated for colon adenocarcinoma. The SMC were isolated from colonic circular muscle layer and cell contraction was assessed. Results: Glicentin caused a dose‐related contraction of SMC, when GLP‐1 determined a contraction of weak amplitude. Exendin‐(9–39), described as a GLP‐1 receptor antagonist, inhibited contraction due to glicentin or GLP‐1. In contrast, on antral SMC from rabbit, GLP‐1 exerts neither relaxation nor contraction; however, exendin‐(9–39) dose dependently reduced the contractile activity of glicentin [glicentin EC50 = 5 pM, exendin‐(9–39) pA2 = −9.36]. Conclusions: The circular muscle from the human colon is a target tissue for glicentin and GLP‐1. Whereas glicentin is a long‐life digestive hormone which would contribute to segmental contraction, the biological activity of GLP‐1 remains unknown on this tissue. On the digestive smooth muscle, exendin‐(9–39) behaved as an antagonist for two members of the glucagon‐receptor family, GLP‐1 and glicentin.
Cultural capital in an understated nation: the case of Scotland
Authors: McCrone David
Published: March 2005

The concept of cultural capital is rarely used to explore specifically national cultural formations. This paper explores how Scotland, with its distinctive national identity, yet its constitutionally subordinate position within the UK offers an interesting case to explore the relationship between nationality and cultural capital. It examines how the concept can be used to unpick collective national identities, and how devolution might have changed its relationship to matters of identity and culture. It is especially concerned to show how Scotland's position within the UK leads to a form of cultural formation caught between two contradictory assumptions: that Scotland is ‘culture‐lite’– insufficiently different from the rest of the UK in terms of cultural markers such as language religion etc to be ‘national’; and on the other hand that Scotland is ‘culture‐heavy’ in so far as its cultural iconography is so hegemonic and distorted that it generates deformed narratives and discourses.
Activation of regenerating geneRegin rat and human hearts in response to acute stress
Authors: Kiji Tatsuya , Dohi Yoshiko , Takasawa Shin , Okamoto Hiroshi , Nonomura Akitaka , Taniguchi Shigeki
Published: March 2005

Recently, the regenerating gene ( Reg) has been documented to play an important role in various regenerating tissues, but it is unknown whether the Reg gene could be activated in the heart. The aim of this study was to reveal the transcriptional activation of Reg in the heart in response to heart stress. We first found REG-1 protein expression in human hearts obtained from autopsied patients who died of myocardial infarction. REG protein was immunohistochemically stained in a fine granular pattern in the cytoplasm of cardiomyocytes. To demonstrate the activation profiles of Reg gene expression in the heart, we quantified the levels of Reg-1 mRNA in rat hearts after coronary artery ligation using real-time RT-PCR. Transient Reg-1 mRNA activation, peaking at 12 h after coronary ligation, was observed mainly in the atria, which was sevenfold higher compared with hearts with pressure overload due to aortic constriction. In contrast, Reg receptor mRNA was expressed intensely in damaged ventricles. Furthermore, Western blot analysis showed the corresponding pattern of Reg protein secretion into the serum after loading, and circulating levels of the protein after myocardial infarction were higher than those after aortic constriction. In conclusion, our results demonstrate for the first time the presence of the Reg/Reg receptor system in damaged hearts. In view of emerging evidence of Reg for tissue regeneration in a variety of tissues/organs, it is proposed that the damaged heart may be a target for Reg action and that Reg may protect against acute heart stress.
Successful Projection of the Time Course of Drug Concentration in Plasma During a 1‐Year Period From Electronically Compiled Dosing‐Time Data Used as Input to Individually Parameterized Pharmacokinetic Models
Authors: Vrijens Bernard , Tousset Eric , Rode Richard , Bertz Richard , Mayer Steve , Urquhart John
Published: March 2005

Pharmacokinetic studies rely on blood sampling at times relative to predefined dosing intervals. Intensive sampling is often done under direct observation of dose taking, which, though costly, virtually eliminates uncertainty about actual dosing times. In contrast, the sparse sampling done in population pharmacokinetic studies relies on patient‐reported times of dosing, the accuracy of which the authors sought to assess by adding electronic monitoring to the usual patient reporting of dosing times. The study involved 35 antiretroviral‐naive, human immunodeficency virus—infected patients and was designed to assess the safety, tolerability, pharmacokinetics, and antiviral activity of prescribed lopinavir/ritonavir (800/200 mg qd or 400/100 mg bid), stavudine, and lamivudine. The present research reports the pharmacokinetic analysis that results from taking into account the patients’ actual dosing histories. Intensive sampling for plasma lopinavir concentrations was done at week 3, and 4 additional predose (trough) concentrations were measured during the next 12 months. Convergence was achieved by fitting a simple 1‐compartment pharmacokinetic model, with first‐order absorption and elimination, to the sparse sampling data, using electronic monitoring—reported times. In contrast, convergence was not achieved using the simple model when steady state was assumed, and the times for the last qd dose or the last 2 bid doses, as reported by the patient, were used as model input. Estimated individual pharmacokinetic parameters were then combined with electronic dosing histories to project each patient's internal drug exposure over long periods of time. This strategy may provide a basis for greatly increasing the informational yield and utility of conventional therapeutic drug monitoring.
Changing Roles: Individual and Family Therapy in the Treatment of Anorexia Nervosa
Authors: O’Halloran M. Sean , Weimer Arlene K.
Published: March 2005

This article presents a case study illustrating the blending of individual cognitive therapy with family therapy in the treatment of anorexia nervosa. Family members explored attributions they made about each other’s behavior. The communication strategies helped this family to communicate more effectively with each other about eating disorders, positive and negative observations in behavior, and ways that the family could be supportive. This approach allowed new behaviors to emerge and began to create new patterns of relating. A significant gain from this approach is that it helped each person face personal weaknesses and to see how the roles they had taken on were very confining to themselves and to other family members.
Examination of the responses of slimy sculpin (Cottus cognatus) and white sucker (Catostomus commersoni) collected on the Saint John River (Canada) downstream of pulp mill, paper mill, and sewage discharges
Authors: Galloway Brendan J. , Munkittrick Kelly R. , Currie Steve , Gray Michelle A. , Curry R. Allen , Wood Craig S.
Published: March 2005

As part of a larger survey on cumulative effects within the Saint John River basin (Canada), a fish survey was conducted near Edmundston (NB, Canada) in the fall of 1999 using slimy sculpin (Cottus cognatus) and white sucker (Catostomus commersoni). The discharge environment receives effluent from the pulp mill, a paper mill, three sewage discharges, and tributaries receiving agricultural runoff. Sculpin collected downstream of the sewage discharges and pulp mill effluent had greater growth, condition, and liver size but no significant differences in gonad size. Stable isotope data indicated slimy sculpin did not move between sites. Female sculpin collected downstream of the paper mill showed no significant differences in length, body weight, age, condition factor, liver size, and gonad size compared to fish from reference sites. Female white sucker collected downstream of the pulp mill did not differ significantly in any measured parameter compared to reference fish. Liver sizes of white sucker from the Saint John River were outside the range considered to be indicative of uncontaminated riverine sites. In 2000, sculpin collected downstream from a poultry-processing facility had larger livers and lower condition factors, suggesting that the site is contaminated. We found no significant differences in sculpin length, weight, condition (except for males), and liver size in sculpin collected downstream from the pulp mill in October 2001. The responses of slimy sculpin and white sucker differed, perhaps in relation to differences in life history characteristics. Results from this study indicate the slimy sculpin is a suitable fish species for monitoring rivers that receive multiple industrial and municipal effluents.
The spatial extent of contaminants and the landscape scale: An analysis of the wildlife, conservation biology, and population modeling literature
Authors: Carlsen Tina M. , Coty Jessie D. , Kercher James R.
Published: March 2005

Many contaminant releases to the terrestrial environment are of small areal extent. Thus, rather than evaluating the ecological impact on species in the immediate vicinity of the release, it may be more ecologically meaningful to determine if population impacts occur at the landscape level. In order to do this, the cumulative impact of all releases in the landscape under consideration must be evaluated. If the release sites are viewed as localized areas that are no longer available for use by ecological receptors (i.e., no longer part of the habitat), this can be thought of as a form of habitat fragmentation. Habitat fragmentation is typically viewed as the loss of large areas of habitat within a landscape, leaving small isolated patches of intact habitat within a hostile matrix. Small-scale contaminant releases, on the other hand, result in small uninhabitable areas within a primarily intact habitat. With this consideration in mind, we analyzed the wildlife and conservation biology literature to determine if information on habitat size requirements such as home-range or critical patch size could inform us about the potential for impact at the landscape level from release sites based on the size of the release alone. We determined that evaluating the impact of release size had to be conducted within a contextual basis (considering the existing state of the landscape). Therefore, we also reviewed the population modeling literature to determine if models could be developed to further evaluate the impact of the spatial extent of chemical releases on the landscape. We identified individual-based models linked to geographic information systems to have the greatest potential in investigating the role of release size with respect to population impacts at the landscape level.
A comparison of the sensitivity of stream benthic community indices to effects associated with mines, pulp and paper mills, and urbanization
Authors: Kilgour Bruce W. , Somers Keith M. , Barton David R.
Published: March 2005

This study examined the relative sensitivities of seven commonly used indices of stream benthic community composition and three multivariate indices to effects associated with mines, pulp and paper mills, and urbanization. The indices included total abundance, number of taxa, diversity (H′), evenness, Hilsenhoff's biotic index (HBI), the BioMAP water quality index (WQI), the percent model affinity (PMA), and the first three ordination axes from a correspondence analysis. The second objective of the study was to determine the degree of redundancy among these indices. Six data sets (two from each of the three types of development) were used to address the objectives. In each data set, replicate benthic samples were collected from reference areas as well as one or more downstream areas exposed to a point-source or non-point-source discharge. The PMA approach and the ordination axes indicated significant differences between the reference and downstream communities for all six data sets (p < 0.05). With the exception of H′, each of the other metrics revealed significant effects associated with one or two, but not all three, types of development. For example, the HBI and WQI indicated significant effects associated with pulp and paper mills and urbanization, but not mining. In all studies, effect sizes (i.e., the standardized difference between means for the reference and exposed areas expressed in units of standard deviations [SDs]) exceeded 2 SDs. However, effect sizes for the PMA and the first or second ordination axis scores were generally larger than effect sizes for the other metrics, indicating that these indices were often the most sensitive indicators of development. In addition, a high degree of redundancy was found among the various metrics, perhaps because the effects were large (i.e., >2 SDs). The greater sensitivity of the ordination axes and the PMA approach emphasizes their value as indices of benthic community composition. As a result, we recommend that any suite of indices used for assessing benthic communities should include these types of multivariate metrics.
Combined effects of humic acids and salinity on solid-phase microextraction of DDT and chlorpyrifos, an estimator of their bioavailability
Authors: Mézin Laurent C. , Hale Robert C.
Published: March 2005

The unbound portion of dissolved hydrophobic environmental contaminants generally is presumed to be the most bioavailable to aquatic organisms. The effects of differing concentrations of Aldrich humic acid (HA) and salinity on the freely dissolved fraction of chlorpyrifos (CPF) and 4,4′-dichlorodiphenyltrichloroethane (DDT) in water were assessed through their relative uptake by solid-phase microextraction (SPME). This extraction method has been recently suggested as a valuable biomimetic tool. Increasing salinity (0–20 parts per thousand [%]) alone had no effect on the uptake of DDT by the SPME fiber, but generally enhanced the SPME uptake of the more water soluble CPF. Solid-phase microextraction uptake of DDT was decreased at an HA concentration of 10 mg/L, but 100 mg/L was required to decrease CPF uptake. Binding of CPF and DDT by HA was greatly reduced by the presence of salt at 5 to 20%. The extent of the HA and salinity effects appeared to be pesticide-dependent. These factors may ultimately impact the contaminant's environmental fate, transport, and bioavailability, for example, in estuarine situations.
Toxicity of mono- and diesters of o-phthalic esters to a crustacean, a green alga, and a bacterium
Authors: Jonsson Susanne , Baun Anders
Published: March 2005

The degradation of phthalic acid diesters may lead to formation of o-phthalic acid and phthalic acid monoesters. The ecotoxic properties of the monoesters have never been systematically investigated, and concern has been raised that these degradation products may be more toxic than the diesters. Therefore, the aquatic toxicity of phthalic acid, six monoesters, and five diesters of o-phthalic acid was tested in three standardized toxicity tests using the bacteria Vibrio fischeri, the green algae Pseudokirchneriella subcapitata, and the crustacean Daphnia magna. The monoesters tested were monomethyl, monoethyl, monobutyl, monobenzyl, mono(2-ethylhexyl), and monodecyl phthalate, while the diesters tested were dimethyl, diethyl, dibutyl, butylbentyl, and di(2-ethylhexyl)phthalate, which were assumed to be below their water solubility. The median effective concentration (EC50) values for the three organisms ranged from 103 mg/L to >4,710 mg/L for phthalic acid, and corresponding values for the monoesters ranged from 2.3 mg/L (monodecyl phthalate in bacteria test) to 4,130 mg/L (monomethyl phthalate in bacteria test). Dimethyl and diethyl phthalate were found to be the least toxic of the diesters (EC50 26.2–377 mg/L), and the toxicity of the other diesters (butylbenzyl and dibutyl phthalate) ranged from 0.96 to 7.74 mg/L. In general, the phthalate monoesters (degradation products) were less toxic than the corresponding diesters (mother compounds).
Influence of hydroxypropyl-β-cyclodextrin on the extraction and biodegradation of phenanthrene in soil
Authors: Reid Brian J. , Stokes Joanna D. , Jones Kevin C , Semple Kirk T.
Published: March 2005

A study was conducted to investigate the effect of hydroxypropyl-β-cyclodextrin (HPCD) on the aging and biodegradation of phenanthrene (PHE) in soil. Soil was spiked with PHE at 25 mgPHE/kgSOIL and HPCD at a range of concentrations from 0 to 3.5 gHPCD/kgSOIL and aged for 1, 84, and 322 d. At each time point, a variety of analyses were performed to assess the loss and aging of the PHE in the soil. Methods included determination of total PHE remaining, dichloromethane (DCM) and butan-1-ol (BuOH) extractions, and determination of PHE extractable by an aqueous HPCD shake extraction. Mineralization assays were also carried out to assess the availability of the PHE to a PHE-degrading bacterial inoculum. It was found that the presence of HPCD in the soils increased PHE loss from the aged soil systems, particularly at the higher application rates. Dichloromethane and BuOH extractabilities were reduced with aging and increasing HPCD concentration, as was the amount of PHE that was extractable using an aqueous HPCD shake extraction or that was available for mineralization. The DCM and BuOH extraction yielded similar results, and both greatly overestimated the availability of the PHE to the degraders, whereas the HPCD extraction results were very similar to that of PHE biodegradation. This study indicates that cyclodextrins have potential for use as alternatives to surfactants in enhancing the desorption/solubilization and degradation of recalcitrant organic contaminants in soil.
Trace metal availability and effects on benthic community structure in floodplain lakes
Authors: Van Griethuysen Corine , Van Baren Joyce , Peeters Edwin T. H. M. , Koelmans Albert A.
Published: March 2005

Effects of contaminants on communities are difficult to assess and poorly understood. We analyzed in situ effects of trace metals and common environmental variables on benthic macroinvertebrate communities in floodplain lakes. Alternative measures of trace metal availability were evaluated, including total metals, metals normalized on organic carbon (OC) or clay, simultaneously extracted metals (SEM), combinations of SEM and acid-volatile sulfide (AVS), and metals accumulated by detritivore invertebrates (Oligochaeta). Accumulated metal concentrations correlated positively with sediment trace metals and negatively with surface water dissolved OC. Sixty-eight percent of the variation in benthic community composition was explained by a combination of 11 environmental variables, including sediment, water, and morphological characteristics with trace metals. Metals explained 2 to 6% of the community composition when SEM — AVS or individual SEM concentrations were regarded. In contrast, total, normalized, and accumulated metals were not significantly linked to community composition. We conclude that examination of SEM or SEM — AVS concentrations is useful for risk assessment of trace metals on the community level.
Comparing behavioral and chronic endpoints to evaluate the response of Lumbriculus variegatus to 3,4,3′,4′-tetrachlorobiphenyl sediment exposures
Authors: Landrum Peter F. , Leppänen Matti , Robinson Sander D. , Gossiaux Duane C. , Burton G. Allen , Greenberg Marc , Kukkonen Jussi V. K. , Eadie Brian J. , Lansing Margaret B.
Published: March 2005

The response of Lumbriculus variegatus to 3,4,3′,4′-tetrachlorobiphenyl (TCBP) was examined with feeding behavior and changes in carbon assimilation by using stable carbon isotopes at 22 and 10°C. The classical measure of feeding behavior determined on a subset of sediment for which the biological burial rate was determined in a companion study allowed direct method comparison. This comparison helped address relationships between biological burial rate, feeding rate, and bioaccumulation. The change in stable isotope composition reflects the total metabolic activity by measuring carbon assimilation rate and was compared to feeding rate, biological burial rate (as determined in the companion study), and reproduction. Decreasing the temperature from 22 to 10°C resulted in a twofold reduction in feeding rate and carbon assimilation. The fractional decline in feeding rate relative to the control mimicked the decline in the biological burial rate with increasing TCBP concentration that was found in the companion study. The bioaccumulation factor declined with increasing TCBP sediment concentration, tracking the feeding rate decline. Stable isotope measures showed differences in metabolic rates between the exposure temperatures but did not distinguish a metabolic rate change at 22°C among TCBP treatments. Likewise, reproduction declined from 22 to 10°C, with no reproduction at 10°C. Like the stable isotope measure, no dose response was found among TCBP treatments at 22°C. The reduction in carbon assimilation rate tracked the reduction in reproduction with lower temperature.
Reproductive and developmental effects of atrazine on the estuarine meiobenthic copepod Amphiascus tenuiremis
Authors: Bejarano Adriana C. , Chandler G. Thomas
Published: March 2005

Atrazine is one of the most widely used herbicides in the United States. Atrazine concentrations in coastal environments chronically range from 90 ng/L to 46 μg/L, with rare but measured concentrations near 60 μg/L at edge-of-field conditions. Chronic atrazine effects on estuarine benthos exposed to environmentally relevant concentrations are unknown. The purpose of this research was to assess atrazine reproductive and developmental effects over multiple-generation exposures of the copepod Amphiascus tenuiremis. Copepods were chronically exposed to two environmentally relevant nominal atrazine concentrations (2.5 and 25 μg/L, and to an environmentally unrealistic concentration (250 μg/L). Chronic exposures were performed using a 96-well microplate life cycle bioassay. Individual stage I copepodites (C1, n = 60/treatment) were reared through two generations (F0 and F1) to sexual maturity and individually mated in microwells containing 200 μl of atrazine solution. Copepod survival across all treatments and generations was >95%. Atrazine did not affect development to reproductive maturity, time to egg extrusion, or time to egg hatch (p > 0.05). However, reproductive failures increased across generations with increasing atrazine concentrations. Reproductive failures in the 0-, 2.5-, 25-, and 250-μg/L atrazine treatments were 11, 11, 20, and 24% for the F0 and 4, 9, 26, and 38% for the F1, respectively. Compared to controls, total nauplii production per female was reduced by approximately 22% in F0 females exposed to 250 μg/L atrazine (p < 0.05), and by approximately 23%, approximately 27%, and approximately 32% in F1 females exposed to 2.5-, 25-, and 250-μg/L atrazine treatments, respectively (p < 0.05). The combined effect of reproductive failure and reduced offspring production significantly reduced total population growth in the F1 generation (p < 0.05) even at atrazine concentrations lower than that considered safe for seawater chronic exposure (26 μg/L).
Reduction of halogenated ethanes by green rust
Authors: O'Loughlin Edward J. , Burris David R.
Published: March 2005

Green rusts, mixed FeII/FeIII hydroxide minerals present in many suboxic environments, have been shown to reduce a number of organic and inorganic contaminants. The reduction of halogenated ethanes was examined in aqueous suspensions of green rust, both alone and with the addition of AgI (AgGR) and CuII (CuGR). Hexachloroethane (HCA), pentachloroethane (PCA), 1,1,1,2-tetrachloroethane (1,1,1,2-TeCA), 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA), 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2-trichloroethane (1,1,2-TCA), 1,1-dichloroethane (1,1-DCA), and 1,2-dibromoethane were reduced in the presence of green rust alone, AgGR, or CuGR; only 1,2-dichloroethane and chloroethane were nonreactive. The reduction was generally more rapid for more highly substituted ethanes than for ethanes having fewer halogen groups (HCA > PCA > 1,1,1,2-TeCA > 1,1,1-TCA > 1,1,2,2-TeCA > 1,1,2-TCA > 1,1-DCA), and isomers with the more asymmetric distributions of halogen groups were more rapidly reduced than the isomer with greater symmetry (e.g., 1,1,1-TCA > 1,1,2-TCA). The addition of AgI or CuII to green rust suspensions resulted in a substantial increase in the rate of halogenated ethane reduction as well as significant differences in the product distributions with respect to green rust alone.
Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, Canada
Authors: Morrissey Christy A. , Bscendell-Young Leah I. , Elliott John E.
Published: March 2005

To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to metals for resident dippers that occupy the main river year-round and altitudinal migrants that breed on higher elevation tributaries because of differences in prey metal levels between locations or possible differences in diet composition. Metals most commonly detected in dipper feather samples in decreasing order were Zn > Cu > Hg > Se > Pb > Mn > Cd > Al > As. Resident dipper feathers contained significantly higher mean concentrations of mercury (0.64 μg/g dry wt), cadmium (0.19 μg/g dry wt), and copper (10.8 μg/g dry wt) relative to migrants. Mass balance models used to predict daily metal exposure for dippers with different diets and breeding locations within a watershed showed that variation in metal levels primarily was attributed to differences in the proportion offish and invertebrates in the diet of residents and migrants. In comparing predicted metal exposure values to tolerable daily intakes (TDI), we found that most metals were below or within the range of TDI, except selenium, aluminum, and zinc. Other metals, such as cadmium, copper, and arsenic, were only of concern for dippers mainly feeding on insects; mercury was only of concern for dippers consuming high fish diets. The models were useful tools to demonstrate how shifts in diet and breeding location within a single watershed can result in changes in exposure that may be of toxicological significance.
Macroinvertebrate community response to pulse exposure with the insecticide lambda-cyhalothrin using in-stream mesocosms
Authors: Heckmann Lars-Henrik , Friberg Nikolai
Published: March 2005

esticides are constantly beingapplied to agricultural catchments, but little is known abouttheir impact onaquatic biota during natural exposure. In the present study, the impact of the pyrethroid lambda-cyhalothrin was studied in an in-stream mesocosm setup. Twice during the summer of 2002, the natural macroinvertebrate community was exposed in situ to a 30-min pulse of lambda-cyhalothrin. Pyrethroid doses were released through a modified drip set with nominal concentrations of 0.10, 1.00, and 10.0 μg L−1 during the first exposure and 0.05, 0.50, and 5.00 μg L−1 in the second exposure. Before, during, and after exposure, drifting macroinvertebrates were caught in nets. Quantitative benthic samples were taken both before and on two occasions after exposure. Macroinvertebrate drift increased immediately after the pulse exposure, with total drift being significantly higher at all concentrations. Gammarus pulex, various Ephemeroptera, Leuctra sp., and Simuliidae were some of the taxa showing the most pronounced drift response. Structural change in the community was found only at 5.00 and 10.0 μg L−1, and recovery occurred within approximately two weeks. The present study may be valuable in assessing extrapolations based on laboratory results as well as in evaluating pyrethroid impact on natural freshwater environments.
Risk of five polycyclic aromatic hydrocarbons in a terrestrial environment: Influence of data variability
Authors: Fauser Patrik , Thomsen Marianne , Scott-Fordsmand Janeck , Sørensen Peter B.
Published: March 2005

The risk of five different pyrogenic polycyclic aromatic hydrocarbons (P AH) toward two soil-dwelling organisms (i.e., springtail [Folsomia fimetaria] and earthworm [Eisenia veneta]) has been investigated with respect to lethality and reproduction at two soil depths in a typical Danish soil. Predicted environmental concentrations (PECs) are calculated with a model describing diffusion, bulk flow, and microbial degradation. Predicted no-effect concentrations (PNECs) are derived from laboratory experiments performed with nominal soil concentrations in the range from 0 to 300 μg PAH/g dry weight. Risk is estimated through a stochastic approach as well as with the conventional point estimate. The point estimate predicts a potential risk for pyrene, log PEC/PNEC = —0.01, with respectto springtail reproduction at 5 cm soil depth. In all other scenarios, the point-estimate log-ratiosare significantly lower than 0. For the stochastic approach risk is defined when the probability for risk (i.e., the probability for log PEC/PNEC > 0), is larger than 5%. The results show that risk is present only for springtail and in the following five scenarios: For anthracene, the probability for risk with respect to lethality is 12% at 5 cm soil depth, and 17 and 5% with respect to reproduction at 5 and 50 cm soil depth, respectively; for pyrene the probability for risk with respect to reproduction is 49 and 14% at 5 and 50 cm, respectively. The results show that risk cannot be defined unambiguously with the two approaches. The probabilistic approach is less restrictive, and even small probabilities may be used as early-warning indications that risk may be posed under unfavorable circumstances.
Effect of cyclodextrin and transformer oil amendments on the chemical extractability of aged [14C]polychlorinated biphenyl and [14C]polycyclic aromatic hydrocarbon residues in soil
Authors: Doick Kieron J. , Burauel Peter , Jones Kevin C. , Semple Kirk T.
Published: March 2005

Sequestration of hydrophobic organic contaminants (HOCs) in soils limits chemical and biological availability. Concerns exist regarding the long-term stability of sequestered contaminants in the environment, and stability needs to be demonstrated if bioavailability considerations are to be adopted into the risk assessment and remediation of contaminated land. The aim of the present study was to test the short-term influence of two organic amendments on the chemical extractability of HOC residues that had been present in soils for more than 12 years. The amendments investigated were cyclodextrin and transformer oil (a light, nonaqueous phase liquid [LNAPL]). The contaminants investigated were fluoranthene and benzo[a]pyrene in one soil and the polychlorinated biphenyls (PCBs) 28 and 52 in a second soil. The addition of cyclodextrin to the soils did not result in a significant increase in chemical extractability of the residues after a 36-d contact time. The addition of transformer oil resulted in an increase in chemical extractability of the PCBs after a 14-d soil-LNAPL contact time and a further increase after a 36-d contact time. The present study demonstrates that the chemical availability of aged HOCs in soil may be influenced by the presence of other chemicals and has implications for the long-term management of contaminated land.
Apoptosis in Cyclosporin A‐Induced Gingival Overgrowth: A Histological Study
Authors: Alaaddinog͠lu Emine Elif , Karabay Gülten , Bulut Şule , Oduncuog͠lu Füsun Bahar , Özdemir Handan , Bulut Ömer Engin , Çolak Turan
Published: March 2005

Background: Cyclosporin A (CsA) is known to induce gingival overgrowth. Apoptosis plays a critical role in the regulation of inflammation and the host immune response. The aim of this study was to investigate apoptosis in CsA‐induced gingival enlargement using electron microscopy examination of keratinocytes.

Methods: Gingiva specimens were collected from 12 CsA‐treated renal transplant patients with gingival overgrowth and eight healthy controls with gingivitis. Clinical findings (probing depth, gingival index, and plaque index) were compared in the two groups. Histological and ultrastructural features of the specimens were also compared, and extent of keratinocyte apoptosis was scored on a three‐tier scale: 0 = no apoptotic cells; 1 = one or two apoptotic cells; 2 = more than two cells.

Results: There were no significant differences between groups with respect to gingiva‐related clinical findings or extent of keratinocyte apoptosis.

Conclusions: The results indicate that the extent of keratinocyte apoptosis in the gingiva of kidney recipients with CsA‐induced gingival overgrowth is similar to that observed in inflamed gingiva of healthy individuals. Further studies on apoptosis of different cell types in the presence of CsA should clarify this agent's role in the pathogenesis of drug‐induced gingival enlargement. J Periodontol 2005;76:166‐170.
Histologic Evaluation of Autogenous Connective Tissue and Acellular Dermal Matrix Grafts in Humans
Authors: Cummings Lewis C. , Kaldahl Wayne B. , Allen Edward P.
Published: March 2005

Background: The clinical success of root coverage with autogenous connective tissue (CT) or acellular dermal matrix (ADM) has been well documented. However, limited histological results of CT grafts have been reported, and a case report of a human block section has been published documenting an ADM graft. The purpose of this study is to document the histological results of CT grafts, ADM grafts, and coronally advanced flaps to cover denuded roots in humans.

Methods: This study included four patients previously treatment planned for extractions of three or more anterior teeth. Three teeth in each patient were selected and randomly designated to receive either a CT or ADM graft beneath a coronally advanced flap (tests) or coronally advanced flap alone (control). Six months postoperatively block section extractions were performed and the teeth processed for histologic evaluation with hematoxylin‐eosin and Verhoeff's stains.

Results: Histologically, both the CT and ADM were well incorporated within the recipient tissues. New fibroblasts, vascular elements, and collagen were present throughout the ADM, while retention of the transplanted elastic fibers was apparent. No effect on the keratinization or connective tissue organization of the overlying alveolar mucosa was evident with either graft. For both materials, areas of cemental deposition were present within the root notches, the alveolar bone was essentially unaffected, and the attachments to the root surfaces were similar.

Conclusion: Although CT and ADM have a slightly different histological appearance, both can successfully be used to cover denuded roots with similar attachments and no adverse healing. J Periodontol 2005;76:178‐186.
EXternal Pelvic REctal SuSpension (Express procedure) for rectal intussusception, with and without rectocele repair
Authors: Williams N S , Dvorkin L S , Giordano P , Scott S M , Huang A , Frye J N R , Allison M E , Lunniss P J
Published: March 2005

Background

The results of conventional treatment for rectal intussusception and rectocele are unpredictable. The aim was to develop a less invasive surgical approach and to evaluate outcome in selected patients.

Methods

Seventeen patients (13 women; median age 47 (range 20–67) years) with rectal evacuatory dysfunction and rectal intussusception, 13 of whom had a rectocele, were selected. The intussusception was corrected by external pelvic suspension of the rectum, using collagen strips attached to the rectal wall and pubis. The rectocele was repaired with a collagen patch. Patients were assessed before and 6 months after surgery by symptom and quality of life questionnaires, anorectal physiological investigation and proctography, and were followed up for a median of 12 months.

Results

Sepsis requiring exploration occurred in two patients but there was no extrusion or need to remove the collagen. Of the 15 patients assessed after surgery, total symptom scores were significantly decreased (P < 0·001) and quality of life scores improved (P < 0·001). Proctographically, the degree of intussusception was improved in ten patients; six patients had normal postoperative proctograms. The rectocele was reduced in size in all patients, and was not demonstrable in eight.

Conclusion

An effective procedure for rectal intussusception and rectocele has been developed in a selected group of patients with marked evacuatory symptoms.
Leukemia inhibitory factor promotes oligodendrocyte survival after spinal cord injury
Authors: Kerr Bradley J. , Patterson Paul H.
Published: March 2005

Injury to the mammalian spinal cord is accompanied by a delayed, secondary wave of oligodendrocyte apoptosis that arises several days after the initial injury. A strong candidate to support oligodendrocyte survival after spinal cord injury is the pleiotropic cytokine, leukemia inhibitory factor (LIF). In vitro, LIF potentiates the differentiation and survival of oligodendrocyte precursors. LIF can also prevent oligodendrocyte apoptosis in response to either growth factor removal or cytotoxic challenge. More recently, in vivo studies have demonstrated that LIF is effective in preventing oligodendrocyte death in a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). We therefore asked whether systemic delivery of LIF could ameliorate oligodendrocyte death in a mouse model of spinal cord injury. We have found that daily administration of LIF (25 μg/kg/day) promotes oligodendrocyte survival after spinal cord injury. Interestingly however, this effect does not appear to be mediated by a direct action of LIF on the oligodendrocyte but rather via an ancillary cell type, which results in augmented expression of another trophic factor capable of supporting oligodendrocyte survival, insulin‐like growth factor 1 (IGF‐1). © 2005 Wiley‐Liss, Inc.
Direct inhibition of interleukin‐2 receptor α‐mediated signaling pathway induces G1 arrest and apoptosis in human head‐and‐neck cancer cells
Authors: Kuhn Deborah J. , Dou Q. Ping
Published: March 2005

Overexpression of the interleukin‐2 receptor (IL‐2R) α chain in tumor cells is associated with tumor progression and a poor patient prognosis. IL‐2Rα is responsible for the high affinity binding of the receptor to IL‐2, leading to activation of several proliferative and anti‐apoptotic intracellular signaling pathways. We have previously shown that human squamous cell carcinoma of a head‐and‐neck line (PCI‐13) genetically engineered to overexpress IL‐2Rα exhibit increased transforming activity, proliferation, and drug resistance, compared to the vector control cells (J Cell Biochem 2003;89:824–836). In this study, we report that IL‐2Rα+ cells express high levels of total and phosphorylated Jak3 protein and are more resistant to apoptosis induced by a Jak3 inhibitor than the control LacZ cells. Furthermore, we used daclizumab, a monoclonal antibody specific to IL‐2Rα, and determined the effects of IL‐2Rα inhibition on cell cycle and apoptosis as well as the involvement of potential cell cycle and apoptosis regulatory proteins. We found that daclizumab induces G1 arrest, associated with down‐regulation of cyclin A protein, preferentially in IL‐2Rα+ cells, but not in LacZ cells. In addition, daclizumab activates apoptotic death program via Bcl‐2 down‐regulation preferentially in IL‐2Rα+ cells. Finally, daclizumab also sensitizes IL‐2Rα+ cells to other apoptotic stimuli, although the effect is moderate. These results indicate that daclizumab inhibits the proliferative potential of IL‐2Rα+ cells via inhibition of cell cycle progression and induction of apoptosis. © 2005 Wiley‐Liss, Inc.
The correlation between blood oxygenation level‐dependent signal strength and latency
Authors: Müller Karsten , Neumann Jane , Lohmann Gabriele , Mildner Toralf , von Cramon D. Yves
Published: March 2005

Purpose

To investigate the relationship between signal strength and latency of the blood oxygenation level‐dependent (BOLD) signal.

Materials and Methods

Several correlation analyses were performed on data obtained in a functional magnetic resonance imaging (fMRI) experiment, where subjects were presented with a simple visual stimulus. The BOLD signal strength was correlated with both the phase shift of the spectral density matrix and time‐to‐peak calculated from trial‐averaged time courses. Correlation coefficients were calculated for visual stimuli of 2, 6, and 15 seconds in duration.

Results

Analyzing all functional runs for the same subject separately, i.e., including for each run all significantly activated voxels, we observed that correlations between phase shift and signal strength, as well as between time‐to‐peak and signal strength, decreased with increasing stimulus length. However, when analyses were restricted to voxels found activated in all functional runs, we observed similar correlations between BOLD signal strength and latency in all runs, independent of the length of stimulation. This result was again obtained for both latency measures: the spectral density phase shift and time‐to‐peak.

Conclusion

For both latency measures, phase shift and time‐to‐peak, a high correlation between BOLD signal strength and latency was observed. We have shown that this correlation is independent of the length of visual stimulation. Thus, the correlation between BOLD signal strength and latency seems to be an inherent property of the BOLD response that is independent of the length of stimulation and can be observed using different methods for determining signal latency. J. Magn. Reson. Imaging 2005;21:489–494. © 2005 Wiley‐Liss, Inc.
Automated computation of low‐energy pathways for complex rearrangements in proteins: Application to the conformational switch of Ras p21
Authors: Noé Frank , Ille Fabian , Smith Jeremy C. , Fischer Stefan
Published: March 2005

The computation of minimum energy paths (MEPs) is an approach for gaining insight into protein conformational transitions that are too slow to be observed with unconstrained molecular dynamics simulations. MEPs have the advantage of providing the energy barrier of the rate‐limiting step(s), allowing discrimination among different paths. Finding low‐energy MEPs for complex transitions, such as those involving rearrangements of the backbone fold or repacking of buried side chains, has hitherto been unfeasible in a reliable, automated manner, the MEP often displaying unphysical behavior, such as the crossing of bonds. Here, this problem is addressed by combining a counterintuitive procedure for generating an initial guess of the path, in which all side chains are shrunk, with the conjugate peak refinement (CPR) method. The effectiveness of the approach is tested on the conformational switch in Ras p21. This conformational transition involves some partial unfolding and re‐folding, a process for which a multitude of pathways are likely to exist and for which a single MEP does not provide a complete description. However, this transition requires some sterically demanding rearrangements, thus testing the ability of a method to find low‐energy pathways free of structurally unphysical events. This is achieved by the present approach, which finds a path whose rate‐limiting barrier is compatible with experiment. This demonstrates that the method can be used to compute plausible pathways for complex rearrangements in proteins in an automated manner that is unbiased by external driving constraints. Proteins 2005. © 2005 Wiley‐Liss, Inc.