bluuebunny/crossref_metadata_2025 huggingface dataset:
Additive effects and potential inhibitory mechanism of some common aromatic pollutants on in vitro mitochondrial respiration
Authors: Beach Andrew C. , Harmon James
Published: October 2006

The in vitro toxicity of multiple hydrophobic compounds was the focus of this study. A mitochondrial respiratory assay, sensitive to perturbations caused by hydrophobic chemicals, was utilized to measure the effects of individual aromatic hydrocarbon pollutants and their mixtures on mitochondrial respiratory function. Benzene, naphthalene, acenaphthene, and 1‐chloronaphthalene, common industrial solvents shown to interact additively in vivo, were evaluated using this in vitro assay system. Mitochondrial respiration was inhibited 50% (EC50) by 525 ppm (6.7 mM) benzene, 15 ppm (117 μM) naphthalene, 3.9 ppm (25.5 μM) acenaphthene, or 3.8 ppm (23.4 μM) 1‐chloronaphthalene. NADH:O2 oxidoreductase (NADH → O2), NADH: ubiquinone oxidoreductase, and ubiquinol:O2 oxidoreductase activities were inhibited by all four compounds, whereas succinate:O2 oxidoreductase, cytochrome c oxidase, and duroquinol: O2 oxidoreductase activities were not inhibited. Inhibition of mitochondrial respiration occurred at the level of ubiquinone (coenzyme Q10) for all four aromatic hydrocarbons. The ultraviolet absorbance spectrum of isolated Q10 was also altered by naphthalene, acenaphthene, or 1‐chloronaphthalene, suggesting a specific interaction between that component of the respiratory chain and these aromatic hydrocarbons. Inhibition by a mixture of 2, 3, or 4 of the compounds tested was additive, reflecting a summation effect of each compound present in the mixture. This additive nature is consistent with previously reported effects of these compounds in vivo and with compounds having similar modes of action. The similar mode of action in vitro is a specific interaction with coenzyme Q10, not a generalized membrane perturbation as speculated to occur in vivo, and is the likely mechanism for the observed additive toxicity.
Regional distribution of neuropeptide‐degrading enzyme activity in the rat brain: Effects of subacute exposure to carbon disulfide
Authors: De Gandarias J. M. , Echevarría E. , Irazusta J. , Casis O. , Casis L.
Published: October 2006

Carbon disulfide, a volatile solvent, is widely used in industry. It has been demonstrated that it causes several neuropsychological symptoms. However, the neurochemical basis of its neurotoxic effect is relatively unknown. In this paper we have measured the effect of subacute i.p. administration on neutral and basic aminopepti‐dase activities in discrete zones of the rat brain using lysine‐ and leucine‐2‐naphtylamides as substrates. Neutral aminopeptidase activity showed a significant decrease in the thalamus and cerebellum with marked (not significant) changes in the hypothalamus, hippocampus, medulla, and occipital cortex. There were no changes in basic ami‐nopeptidase activity. It is suggested that amino‐peptidase activity could play a role in carbon disulfide neurotoxic action in the aforementioned regions by generating changes in several neuropeptide levels.
Substrate specificity of rat liver aldehyde dehydrogenase with chloroacetaldehydes
Authors: Sharpe A. L. , Carter D. E.
Published: October 2006

Chlorinated acetaldehydes have been the focus of research due to their role as reactive intermediates and their possible occurrence in chlorinated drinking water. This study investigated the in vitro substrate specificity of cytosolic and mitochondrial rat liver aldehyde dehydrogenase toward these compounds. Monochloroacetaldehyde was found to be extensively metabolized by these enzymes, to an even greater extent than the standard substrate propionaldehyde. Dichloroacetaldehyde was metabolized to a much lesser extent, and chloral hydrate is not metabolized by this enzyme family. The KmM (mM) and Vmax (Vmax for propionaldehyde set to 100) values with the low Km cytosolic enzyme were monochloroacetalde‐hyde 0.046. and 582, and dichloroacetaldehyde 0.13 and 54.9, and those with the high Km cytosolic en zyme were dichloroacetaldehyde 0.35 and 23.4. The values with the low Km mitochondrial enzyme were monochloroacetaldehyde 0.057 and 462 and dich loroacetaldehyde 0.038 and 12.9, and those with the high Km mitochondrial enzyme were monochloroacetaldehyde 0.024 and 55.5 and dichloroacetaldehyde 0.29 and 3.44. These data suggest that aldehyde dehydrogenase plays a significant role in the metabolism of monochloroacetaldehyde and, to some extent, dichloroacetaldehyde. Some evidence also suggested that alcohol dehydrogenase plays a significant role in the metabolism of dich loroacetaldehyde and chloral hydrate.
Changes in brain enkephalin immunostaining after acute carbon disulfide exposure in rats
Authors: de Gandarias J. M. , Echevarría E. , Múgica J. , Serrano R. , Casis L.
Published: October 2006

Carbon disulfide neurotoxic mechanism in the brain is still not completely clear. In this work, the effect of carbon disulfide exposure in rats on the enkephalinergic neuromodulatory system is described. Caudatus‐putamen showed no changes in immunostaining for met‐enkephalin when compared with controls. However, a marked reduction in met‐enkephalin immunostaining in the central amygdaloid nuclei and the globus pallidus was measured, with a parallel elevation in the lateral septal nucleus and the parietal cortex. It is suggested that enkephalinergic neuromodulatory system could play a role in carbon disulfide neurotoxicity.
The role of cytochrome P450 2C3 in rabbit liver microsomal metabolism of 1‐nitropyrene and 3‐nitrofluoranthene
Authors: Howard Paul C. , McManus Michael E. , Koop Dennis R.
Published: October 2006

The male rabbit liver microsomal cytochrome P450 metabolism of 1‐nitropyrene and 3‐nitrofluoranthene was investigated. In this study, we used inhibitory antibodies specific for rabbit P450 2C3 and determined that, in untreated male rabbit liver microsomes, the antibody inhibited approximately 75% of the cytochrome P450‐mediated C‐oxidation of both 1‐nitropyrene and 3‐nitrofluoranthene. These results verify our previous prediction that mainly one cytochrome P450 is responsible for microsomal metabolism of 1‐nitropyrene in the untreated rabbit liver.
Inhibition studies on the involvement of flavoprotein reductases in menadione‐ and nitrofurantoin‐stimulated oxyradical production by hepatic microsomes of flounder (Platichthys flesus)
Authors: Lemaire Philippe , Livingstone David R.
Published: October 2006

Inhibitors of mammalian cytochrome P450 and P450 reductase were used to investigate the enzymes in flounder (Platichthys flesus) hepatic microsomes involved in the stimulation of NAD(P)H‐dependent iron/EDTA‐mediated 2‐keto‐4‐methiolbutyric acid (KMBA) oxidation (hydroxyl radical production) by the redox cycling compounds menadione and nitrofurantoin. Inhibitors were first tested for their effects on flounder microsomal P450 and flavoprotein reductase activities. Ellipticine gave type II difference binding spectra (app. Ks 5.36 μM; ΔA max 0.16 nmol‐1 P450) and markedly inhibited NADPH‐cytochrome c reductase, NADPH‐cytochrome P450 reductase, and monooxygenase (benzo[a]pyrene metabolism) activities. 3‐aminopyridine adenine dinucleotide phosphate (AADP; competitive inhibitor of P450 reductase) inhibited NADPH‐cytochrome c but not NADH‐cytochrome c or NADH‐ferricyanide reductase activities. Alkaline phosphatase (inhibitor of rabbit P450 reductase) stimulated NADPH‐cytochrome c reductase activity seven fold but had less effect on NADH‐reductase activities. AADP inhibited nitrofurantoin‐ and menadione‐stimulated KMBA oxidation by 45 and 17%, respectively, indicating the involvement of P450 reductase at least in the former. In contrast, ellipticine had relatively little effect, possibly because, unlike cytochrome c, the smaller xenobiotic molecules can access the hydrophilic binding site of P450 reductase. Alkaline phosphatase stimulated NAD(P)H‐dependent basal and xenobiotic‐stimulated KMBA oxidation, showing general consistency with the results for reductase activities. Overall, the studies indicate both similarities (ellipticine, AADP) and differences (alkaline phosphatase) between the flounder and rat hepatic microsomal enzyme systems.
Autoprotection: Stimulated tissue repair permits recovery from injury
Authors: Mehendale Harihara M. , Thakore Kashyap N. , Rao C. Vaman
Published: October 2006

Autoprotection is a phenomenon whereby prior exposure to a small dose of a chemical results in protection against a subsequently administered lethal dose of the same compound. While CCl4 autoprotection has been studied the most, it has also been demonstrated for other chemicals. Recent studies indicate that the prevailing concept of decreased bioactivation of the normally lethal dose of CCl4 owing to decreased hepatic microsomal cytochrome P‐450

Abbreviations used: CD, chlordecone; cyt. P‐450, cytochromes P‐450; M, mirex; N, normal diet; PB, phenobarbital.

content can not be supported by direct end points of liver injury such as necrosis. These findings suggest a pivotal role for hepatocellular division and tissue healing processes stimulated by the protective dose in the mechanism of autoprotection. Augmentation of hepatocellular regeneration and tissue repair, stimulated by the protective dose, appears to permit timely recovery and restoration of hepatic structure and function. In the absence of the protective dose, hepatocellular division is substantially deficient and it occurs too late to tip the delicate balance between recovery from injury and progression of massive injury in favor of recovery. Abolition of autoprotection by colchicine antimitosis, under conditions where metabolism and disposition of CCl4 are not altered, is supportive of this concept. Selective colchicine antimitotic suppression of the early phase of hepatocellular division and tissue repair induced by a low dose of CCl4 results in progression of toxic liver injury, leading to hepatic failure and mortality. Studies have shown that pretreatment with phenobarbital results in postponed low‐dose CCl4‐stimulated cell division by 24 hours, which accordingly postpones the optimal autoprotection. These findings provide discrete evidence to suggest that the protective dose‐stimulated hepatocellular division and tissue repair underlies the mechanism of autoprotection. These new insights reveal that in contrast to the widely held concept, the ultimate outcome of toxic injury is determined by whether a prompt stimulation of sustainable tissue repair can occur rather than by the magnitude of the injury inflicted by a toxic chemical.
Phospholipase A2 activation in cultured mouse hepatocytes exposed to tumor necrosis factor‐α
Authors: Adamson Gregory M. , Carlson Timothy J. , Billings Ruth E.
Published: October 2006

High concentrations of tumor necrosis factor α (TNFα) are cytotoxic to cultured hepatocytes. Impairment of energy metabolism and generation of an intracellular oxidant stress are important events in the pathogenesis of this toxicity (6). In the present study, we have examined the role of phospholipase A2 activation in TNFα‐in‐duced toxicity in mouse hepatocytes, since it has been reported to play a key role in TNFα cytolytic activity in other cell types. Recombinant murine TNFα (0.1 μg/mL) caused a dose‐dependent increase in PLA2 activity in cultured mouse hepatocytes. The increase in PLA2 activity was observed after only 0.5 hour of exposure (152 ± 10% of control), and continued to increased over the first 4 hours of exposure (292 ± 32%). However, TNFα‐induced GSSG efflux and ATP depletion did not occur until after 2 hours of exposure. Furthermore, a small level of cytotoxicity was observed after a 24 hour incubation period. Putative PLA2 inhibitors, chlorpromazine (CPZ) and 4‐bromophenacyl bromide (BPB), both prevented the TNFα‐induced increase in PLA2 activity. They also reduced ATP depletion, GSSG efflux, and cytotoxicity. The PLA2 inhibitor, manoalide (a natural marine product), completely prevented PLA2 activation and cytotoxicity induced by TNFα. Pretreatment of hepatocytes with cycloheximide, to inhibit protein synthesis, increased TNFα‐induced cytotoxicity. Cycloheximide pretreatment also potentiated PLA2 activation, ATP depletion, and GSSG efflux. CPZ and BPB both reduced the extent of PLA2 activation, ATP depletion, GSSG formation, and cytotoxicity in the cycloheximide pretreated cells exposed to TNFα. Taken together, these results demonstrate that TNFα activates PLA2 which occurs prior to other deleterious events in hepatocytes, and that inhibition of PLA2 activity reduces cell injury by TNFα. This suggests that PLA2 activation may lead to impairment of energy metabolism, an oxidant stress, and cytotoxicity in cells exposed to TNFα. Additionally, protein synthesis inhibition potentiates TNFα induction of PLA2 and toxicity, suggesting that there is a protein‐synthesis‐dependent protective mechanism in hepatocytes which ameliorates the effects induced by PLA2. These findings provide strong evidence that PLA2 activation plays an important role in the pathogenesis of toxicity induced by TNFα in cultured mouse hepatocytes.
Hepatic cytochrome P450 2B induction by ethyl/ phenyl‐substituted congeners of phenobarbital in the B6C3F1 mouse
Authors: Nims Raymond W. , Lubet Ronald A. , Diwan Bhalchandra A. , Mellini Donna W. , Utermahlen William E. , Thomas Paul E.
Published: October 2006

The abilities of structural congeners of phenobarbital to induce immunoreactive hepatic cytochrome P450 2B (CYP2B) protein and associated catalytic activity (benzyloxyresorufin O‐dealkylation) in the male B6C3F1 mouse were examined. Interspecies differences in inducing ability were examined through comparison of the results with induction data obtained previously with the male F344/NCr rat. The congeners were administered in the diet for 2 weeks at concentrations equimolar to 500 ppm of the prototype CYP2B inducer, phenobarbital. Of the series of compounds tested, phenobarbital was the most effective inducer of benzyloxyresorufin O,‐dealkylation and immunoreactive CYP2B protein, with 2‐ethyl‐2‐phenylsuccinimide, 5‐ethyl‐5‐phenylhydantoin, primidone, and glutethimide being only 19–42% as effective. 5‐Ethyl‐5‐phenyloxazolidinedione and the ring‐opened and decarboxylated congeners, N‐(2‐ethyl‐2‐phenylacetyl)urea and 2‐ethyl‐2‐phenyl‐malonamide, displayed minimal induction of these catalytic activities. Dose‐response experiments performed with 5‐ethyl‐5‐phenylhydantoin indicated that the intrinsic CYP2B‐inducing activity of this congener was as great as that of phenobarbital in the mouse, although a fourfold greater dietary concentration of this hydantoin (2000 ppm) was required to elicit a response equivalent to that caused by 500 ppm phenobarbital. When extent of induction was related to serum total xenobiotic concentration rather than to administered dietary concentration, the potencies of the two congeners were determined to be more similar (58 vs. ≥78 μ M for phenobarbital and 5‐ethyl‐5‐phenylhydantoin, respectively).
N‐Acetyl‐l‐cysteine abolishes the bromoethylamine‐induced choline incorporation into renal papillary tissue
Authors: Thielemann L. E. , Rodrigo R. A. , Oberhauser E. W. , Rosenblut G. , Videla L. A.
Published: October 2006

The role of regenerative processes in the protective effect of N‐acetyl‐L‐cysteine (NAC) against bromoethylamine‐induced renal papillary necrosis was assessed in rats given bromoethylamine (BEA) (1.2 mmol/kg), N‐acetylcysteine (6 mmol/kg), or N‐acetylcysteine plus BEA. Renal papillary slices were dissected after 15 hours of treatment, and 14C‐choline incorporation into total phospholipid, lysophosphatidylcholine, sphingomyelin, and phosphatidylcholine was measured. Bromoethylamine elicited an increase in the incorporation of 14C‐choline into choline‐containing phospholipid, an effect that was abolished when N‐acetylcysteine was administered prior to bromoethylamine. These studies indicate that the defensive mechanism of N‐acetylcysteine against bromoethylamine‐induced renal papillary necrosis is not related to regenerative processes and that N‐acetylcysteine abolishes the bromoethylamine‐induced choline incorporation into papillary phospholipid. © 1996 John Wiley & Sons, Inc.
Morphological specializations of baleen whales associated with hydrodynamic performance and ecological niche
Authors: Woodward Becky L. , Winn Jeremy P. , Fish Frank E.
Published: October 2006

Feeding behavior, prey type, and habitat appear to be associated with the morphological design of body, fluke, and flippers in baleen whales. Morphometric data from whaling records and recent stranding events were compiled, and morphometric parameters describing the body length, and fluke and flipper dimensions for an “average” blue whale Balaenoptera musculus, humpback whale Megaptera novaeangliae, gray whale Eschrichtius robustus, and right whale Eubalaena glacialis were determined. Body mass, body volume, body surface area, and fluke and flipper surface areas were estimated. The resultant morphological configurations lent themselves to the following classifications based on hydrodynamic principles: fast cruiser, slow cruiser, fast maneuverer, and slow maneuverer. Blue whales have highly streamlined bodies with small, high aspect ratio flippers and flukes for fast efficient cruising in the open ocean. On the other hand, the rotund right whale has large, high aspect ratio flukes for efficient slow speed cruising that is optimal for their continuous filter feeding technique. Humpbacks have large, high aspect ratio flippers and a large, low aspect ratio tail for quick acceleration and high‐speed maneuvering which would help them catch their elusive prey, while gray whales have large, low aspect ratio flippers and flukes for enhanced low‐speed maneuvering in complex coastal water habitats. J. Morphol., 2006. © 2006 Wiley‐Liss, Inc.
Skeletal elements within teleost eyes and a discussion of their homology
Authors: Franz‐Odendaal Tamara A. , Hall Brian K.
Published: October 2006

Scleral ossicles and scleral cartilages form part of the craniofacial skeleton of many vertebrates. Some vertebrates, including all birds and most reptiles, but excluding most mammals, have scleral cartilages as well as scleral ossicles supporting their eyes. The teleost equivalent of these elements has received little attention in the literature. From radiographic and whole‐mount analyses of over 400 individuals from 376 teleost species, we conclude that the teleost scleral skeletal elements (ossicles and cartilage) differ significantly from those of reptiles (including birds). Scleral ossicles in teleosts have different developmental origins, different positions within the eyeball, and different relationships with the scleral cartilaginous element than those in reptiles. From whole‐mount staining of a growth series of four species of teleost (Danio rerio, Salmo salar, Esox lucius,andAlosa pseudoharengus), we interpret the development of these elements and show that they arise from within an Alcian blue‐staining cartilaginous ring that develops around the eye earlier in development. We present possible scenarios on the evolution of these scleral skeletal elements from a common gnathostome ancestor, and consider that teleost scleral skeletal elements may not be homologous to those in reptiles. Our study indicates that homologycannot be assumedfor these elements, despite the fact that they share the same name, scleral ossicles. J. Morphol., 2006. © 2006 Wiley‐Liss, Inc.
Glenohumeral kinematics following total shoulder arthroplasty: A finite element investigation
Authors: Hopkins Andrew R. , Hansen Ulrich N. , Amis Andrew A. , Taylor Mark , Emery Roger J.
Published: October 2006

The osseous geometry of the glenohumeral joint is naturally nonconforming and minimally constrained, and the joint's stability is maintained by action of the rotator cuff muscles. Damage to these muscles is often associated with joint degeneration, and a variety of glenoid prostheses have been developed to impart varying degrees of stability postoperatively. The issues of conformity and constraint within the artificial shoulder have been addressed through in vivo and in vitro studies, although few computational models have been presented. The current investigation presents the results of three‐dimensional finite element analyses of the total shoulder joint and the effects of design parameters upon glenohumeral interaction. Conformity was shown not to influence the loads required to destabilize the joint, although it was the principal factor determining the magnitude of humeral head translation. Constraint was found to correlate linearly with the forces required to dislocate the humeral head, with higher constraint leading to slightly greater humeral migration at the point of joint instability. The model predicts that patients with a dysfunctional supraspinatus would experience frequent eccentric loading of the glenoid, especially in the superior direction, which would likely lead to increased fixation stresses, and hence, a greater chance of loosening. For candidates with an intact rotator cuff, the models developed in this study predict that angular constraints of at least 14° and 6.5° in the superoinferior and anteroposterior axes are required to provide stable unloaded abduction of the humerus, with larger constraints of 18° and 10° necessitated by a dysfunctional supraspinatus. The tools developed during this study can be used to determine the capacity for different implant designs to provide resistance to excessive glenohumeral translations and reduce the potential for instability of the joint, allowing surgeons to optimize postoperative functional gains on a patient by patient basis. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:108–115, 2007
Apparent ileal digestibility of amino acids in feed ingredients determined with broilers and layers
Authors: Huang Kim H , Ravindran Velmurugu , Li Xiuhua , Ravindran Ganesharanee , Bryden Wayne L
Published: October 2006

The apparent ileal digestibility of amino acids in eight feed ingredients were determined using broilers and layers. The ingredients included three cereals (wheat, sorghum and maize), one cereal by‐product (wheat middlings), three oilseed meals (canola, cottonseed and soybean meals) and one animal protein meal (meat and bone meal). Dietary protein in the assay diets was supplied solely by the test ingredient. All diets contained 20 g kg−1 acid‐insoluble ash as an indigestible marker, and each diet was offered ad libitum in mash form to five replicate pens of 42‐day‐old broilers and 60‐week‐old layers. The digestibility coefficients of most amino acids for wheat and sorghum were similar (P > 0.05) in broilers and layers. The digestibility of most amino acids for maize was higher (P < 0.05) in broilers compared to those in layers. The digestibility of individual amino acid for wheat middlings was higher (P < 0.05) in layers than in broilers. In general, the digestibility of amino acids for cottonseed meal, soybean meal, and meat and bone meal were similar (P > 0.05) between broilers and layers. The influence of class of bird on digestibility in canola meal was variable. The digestibility of threonine, valine, isoleucine, leucine, phenylalanine, glutamic acid and alanine were higher (P < 0.05), and those of methionine, histidine and lysine were lower (P < 0.05) in broilers compared to layers. These results suggest that the practice of using amino acid digestibility values generated with broilers for layers may not be appropriate for all feed ingredients. Copyright © 2006 Society of Chemical Industry
Search history tools for user support in information retrieval systems: Evaluation results from an iterative, user‐centered process
Authors: Kaur Manpreet , Komlodi Anita , Komlodi Tamas , Win Khine
Published: October 2006

This poster describes the results of usability evaluation of a novel search history tool and a set of iteratively developed user interface design guidelines for search histories that support execution of complex tasks by information seekers. Search histories have a great potential in search support. To support the information seekers' needs, an integrated search history tool was developed based on the results of an extensive user study of attorneys and law librarians' memory use in searching and is described in the poster. This tool has been iteratively refined through a cooperative design process and two cycles of usability evaluations in legal and medical domains. An integrated and interactive search history display is proposed with user annotations and marking. The history displays details of search steps and can be selectively edited by users. An additional notepad area affords flexible results collection and early integration via user annotations and notes. The evaluation of the search history tool shows great promise in providing improved search history support for information seekers for complex tasks. The results of the evaluation validated the user interface design guidelines for search histories and will be described in this poster. It is hoped that these results will enable the designers of IR systems to better integrate historical information into their systems and provide improved support for users.
Selecting and measuring task characteristics as independent variables
Authors: Kim Soojung , Soergel Dagobert
Published: October 2006

This paper presents a first step toward a systematic framework for organizing numerous task characteristics or variables that are important in studying the effect of task on information behavior. The paper discusses issues related to selecting, operationalizing, and measuring task characteristics to be used as independent variables. It assembles a list of task characteristics and task classifications based on the characteristics to identify potential independent variables. The study also addresses research design issues to study the effect of task characteristics on information seeking and task performance. Finally, it summarizes findings about relationship between particular task characteristics and information seeking to help researchers form new hypotheses.
A phase‐model of the cross‐cultural learning process of LIS international doctoral students: Characteristics and interventions
Authors: Mehra Bharat
Published: October 2006

This paper develops a phase‐model of the cross‐cultural learning process of LIS international doctoral students and provides a consolidated, in‐depth, and comprehensive look at their experiences that extends prior anecdotal and survey‐based efforts. Semi‐structured interviews along with informal discussions, analysis of electronic interactions, and observations as a participant researcher identify cross‐cultural learning experiences of all the twenty‐two international doctoral students from a representative LIS program in the United States. The phases in the model of the cross‐cultural learning process represent significant cognitive (thoughts), affective (feelings), and physical (actions) aspects of the experiences of LIS international doctoral students. Mapping participants' concerns and challenges during each phase is used to highlight interventions at the level of discipline, program, faculty, doctoral student community, and individual student that together provide a practical application to the research. Proposed interventions need to be holistically applied in conjunction with each other to promote mutual “two‐way” learning where international students learn from the discipline and the discipline learns from the international students. Such an approach suggests symbiotic connections between improvements in effectiveness of student learning and efforts to tap into the cultural knowledge of international students to further growth in internationalization of LIS education in the United States.
Automated analysis of database usage logs in a metasearch environment: The library of Texas experience
Authors: Oguz Fatih , Moen William E.
Published: October 2006

The poster presents an overview of a research and development effort for a mechanism to produce reliable usage reports for the Library of Texas (LOT) Resource Discovery Service (RDS) metasearch application. The RDS Log Analyzer was designed and implemented by the Texas Center for Digital Knowledge project team as part of a contract with the Texas State Library and Archives Commission to support the LOT RDS. Developers of the RDS application had requirements to implement a mechanism for capturing RDS user transactions in custom log files.
Inter‐database annotation linkages in model organism databases
Authors: MacMullen W. John
Published: October 2006

Inter‐database linkage via annotations is one approach to the integration of knowledge in the biomedical domain, which is often fragmented by specialization. This pilot study examined annotations in ten model organism databases and the Gene Ontology (GO) to assess explicit and implicit linkages between organisms. The databases had similar annotation processes, content, and knowledge, with some variation due to organizational objectives and technology infrastructure. While all databases had the potential to be linked to all others via GO, only some databases had non‐GO links to others. This may be due in part to a lack of biologically significant relationships among some of the organisms, or that putative relationships between them that exist in GO have not yet been explored.
Information science practice in a historical perspective: Preliminary findings of an oral history project
Authors: Pozzi Ellen , Dalbello Marija
Published: October 2006

Oral history is a phenomenological method of historical inquiry. It is applied to the study of the organizational field of information science through interviews with members of the New Jersey chapter of the national information science organization )ASIST). Their views on the identity of the chapter and their own professional identity in that context, and on the development and maturation of information science field over the past thirty years are considered in the sociology of culture framework. This approach can open new directions for historical inquiry of information science in the national context, understanding the research / practice dynamics, and the institutionalization of information science field.
MARTT: Using induced knowledge base to automatically mark up plant taxonomic descriptions with XML
Authors: Cui Hong
Published: October 2006

Despite the sub‐language nature of taxonomic descriptions of plants, researchers warned about the large variations among different collections of descriptions in terms of information contents and presentations. These variations impose a serious challenge to the development of automatic tools for the semantic markup of large volumes of free‐text descriptions. This paper presents a new approach to automatic markup of multiple collections of taxonomic descriptions with XML. The effectiveness of the approach was demonstrated with markup experiments using three contemporary floras. The markup system, MARTT, was based on supervised machine learning algorithms and enhanced by machine learned association rules representing certain types of domain knowledge and conventions. Experiments showed that our simple and efficient markup algorithm outperformed popular general‐purpose algorithms (including SVMs) across different floras. More importantly, the results demonstrated that the domain knowledge learned from one flora was useful for improving the markup performance on a second flora, especially on elements with sparse training examples. The system design and the evaluation of markup algorithms are reported in this paper. The study on the effectiveness of the induced knowledge base will be reported in a later paper. In this paper, common practices of flora authors and the potentials of MARTT system for improving the efficiency and effectiveness of the creation, organization, and utilization of plant descriptions are also discussed.
Concentrations and magnetization transfer ratios of metabolites in gray and white matter
Authors: McLean Mary A. , Barker Gareth J.
Published: October 2006

The concentrations and magnetization transfer ratios (MTRs) in gray matter (GM) and white matter (WM) of N‐acetyl aspartate (NAA), creatine (Cr), choline (Cho), myo‐inositol (Ins), and glutamate plus glutamine (Glx) were investigated using magnetic resonance spectroscopic imaging (MRSI). The macromolecule (MM) baseline was studied separately using a metabolite‐nulling inversion. Three data sets were collected from a point‐resolved spectroscopy (PRESS)‐selected volume (TE/TR = 30/3000 ms) of human frontal lobe in vivo: one with MT pulses applied, one with an inversion pulse to null small metabolites, and one with no inversion or MT pulses. The MM signal, which was analyzed by integrating the metabolite‐nulled spectrum between 0 and 3 ppm, was estimated to be 38% higher in GM than in WM. MM subtraction decreased the signal‐to‐noise ratio (SNR) and also decreased the reliability of LCModel quantification of most metabolites, but may have improved the accuracy of quantification of Glx. Glx and Cr were both found to correlate strongly with the GM volume fraction of the voxels. Cr showed the highest MTR, but the other metabolites also showed some attenuation of signal when the MT pulses were applied. The MTRs did not correlate with the GM volume fraction, which implies that the local environment of metabolites does not differ markedly between GM and WM. Magn Reson Med 2006. © 2006 Wiley‐Liss, Inc.
Sources of functional apparent diffusion coefficient changes investigated by diffusion‐weighted spin‐echo fMRI
Authors: Jin Tao , Zhao Fuqiang , Kim Seong‐Gi
Published: October 2006

The mechanism behind previously observed changes in the apparent diffusion coefficient (ADC) during brain activation is not well understood. Therefore, we investigated the signal source and spatial specificity of functional magnetic resonance imaging (fMRI) ADC changes systematically in the visual cortex of cats using diffusion‐weighted (DW) spin‐echo (SE) fMRI with b‐values of 2, 200, and 800 s/mm2, and echo times (TE) of 16, 28, and 60 ms at 9.4 T. For b ≥ 200 s/mm2, no ADC changes were detected in brain parenchyma, suggesting a minimal tissue contribution to the ADC change. For b ≤ 200 s/mm2, TE‐dependent ADC increases were observed. When the venous blood contribution was minimized, the ADC change was higher at the middle cortical layer than at the cortical surface, which is mainly attributed to a functional elevation in arterial blood volume. At TE = 16 ms, the highest ADC changes occurred at the cortical surface with its large draining veins, which can mainly be explained by an additional contribution from the venous blood oxygenation changes. Our TE‐dependent ADC results agree with computer simulations based on a three‐compartment model. The contribution of arterial blood volume changes in ADC fMRI offers an improvement in spatial localization for SE‐BOLD fMRI studies. Magn Reson Med 2006. © 2006 Wiley‐Liss, Inc.
Pyrrolizidine alkaloids from Senecio leucanthemifolius and Senecio rodriguezii
Authors: Roeder Erhard , Bourauel Thomas
Published: October 2006

Two toxic pyrrolizidine alkaloids were isolated from Senecio leucanthemifolius and six from Senecio rodriguezii. Their structures were determined by spectroscopic methods. © 1992 Wiley‐Liss, Inc.
Cytolysins increase intracellular calcium and induce eicosanoids release by pheochromocytoma PC12 cell cultures
Authors: Raya Saleh Abu , Trembovler Victoria , Shohami Esther , Lazarovici Philip
Published: October 2006

Cytolysins are the most commonly occurring toxins among bacteria, plants, and animals. By disturbing cell membrane, they impair ionic permeability, leading to cell death. In an attempt to investigate cytolysin action on catecholaminergic neurons, we have treated pheochromocytoma cell cultures with Strep‐tolysin S, Staphylococcus aureus α and δ, Stoichatus, Parcelsin, and cobra direct lytic factor. To measure neurotoxicity, PC12 cultures were loaded with 51Cr and exposed for 1 hr at 37°C to different concentrations of cytolysins. Cytotoxic dose‐response curves have been generated resulting in CD50 (cytotoxic dose 50%) in the range of 1–50 μg toxin/culture. Using subcytotoxic concentrations of cytolysins (which are of clinical relevance), changes on intracellular calcium were measured by Fura‐2 fluorescence technique. Addition of either Stoichatus toxin and tetanolysin or streptococcus and staphylococcus cytolysins to PC12 cells caused rapidly or gradually a progressive increase in [Ca2+]i, respectively. Under similar conditions, samples of PC12 culture medium were assayed for 3H‐arachidonic acid released and by radioimmunoassay for the content of PGE2 (prostaglandin), TXB2 (stable metabolite of thromboxane), and 5‐HETE (hydroxy acid lipoxygenase product). PLA2 was activated 4.5–6.0‐fold and the levels of all three eicosanoids were increased by 2.5–9‐fold (PGE2), 4–6‐fold (TXB2), and over 100‐fold (5‐HETE) by Stoichatus and Parcelsin cytolysins. Upon treatment with Streptolysin S and staphylococcus α toxins PLA2 (phospholipase A2) was slightly activated (1.5‐fold) and the levels of PGE2 and TXB2 increased 1.3–2.0‐fold and that of 5‐HETE up to 30‐fold. These results indicate that the increased intracellular calcium followed by PLA2 activation and eicosanoid production and release might be involved in neurotoxic action of cytolysins. © 1992 Wiley‐Liss, Inc.
Isolation and sequence analysis of peptides from the venom of Protonectarina sylveirae (hymenoptera‐vespidae)
Authors: Dohtsu Kunihiko , Okumura Kaoru , Hagiwara Ken'Ichi , Palma Mario Sergio , Nakajima Terumi
Published: October 2006

Three new venom peptides were isolated from the Brazilian wasp; Protonectarina sylveirae and their complete amino acid sequences were determined by Edman degradation as well as by FAB‐mass spectrometry. One (P‐8) of them was a new analog of mastoparan family; therefore, we named it Protonectarina mastoparan. Another peptide (P‐10) had an amino acid sequence homolosy with Ves‐CP‐T, a chemotactic peptide of wasp venom, and bombolitin‐V, the venom peptide from bumblebee. The third peptide (P‐6) was structurally unique, possessing an intramolecular disulfide bond. Not only Protonectarina mastoparan (P‐8) but also P‐6 and P‐10 caused histamine release from rat peritoneal mast cells as potently as mastoparan (EC50 s were about 1 × 10−6 M for P‐6 and 2 × 10−6 M for P‐10). In addition, P‐10 in a concentration higher than 1 × 10−5 M induced hemolysis though whose hemolytic activity was about a half potency of that of mastoparan. However, P‐6 did not cause hemolysis up to the concentration of 10μM. We have named them sylverin for the peptide P‐6 and protonectin for the peptide P‐10. © 1992 Wiley‐Liss, Inc.
Toxicity of cotton phytoalexins to zoopathogenic fungi
Authors: Mace Marshall E. , Stipanovic Robert D. , Bell Alois A.
Published: October 2006

The sesquiterpenoid phytoalexins desoxyhemigossypol, desoxymethoxyhemigossypol, and hemigossypolone formed in cotton (Gossypium hirsutum and G. barbadense) stem xylem infected with Verticillium dahliae were shown to be highly toxic to zoopathogenic fungi. This appears to be the first study of the toxicity of terpenoid phytoalexins to zoopathogenic fungi. The toxicities of the phytoalexins expressed as MIC (μg ml−1) values were 8 to 128 against four isolates of Candida albicans and one isolate of Cryptococcus neoformans. These highly toxic compounds or their derivatives may prove useful for the treatment of animal mycoses. © 1992 Wiley‐Liss, Inc.
Occurrence of nivalenol, deoxynivalenol, and zearalenone in imported cereals in Papua, New Guinea
Authors: Yuwai Kuri E. , Rao Koyyalamudi Sundar , Singh Kirpal , Tanaka Toshitugi , Ueno Yoshio
Published: October 2006

A preliminary survey for the natural occurrence of Fusarium mycotoxins—nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN)—in cereals imported mostly from Australia to Papua, New Guinea (PNG) in 1991 was carried out by TLC, GLC, and HPLC analysis. The data have revealed various kinds of cereals and cereal flours, such as wholemeal flour, millet meal, corn flour, brown trukai rice, and others, were significantly contaminated with these mycotoxins in various concentrations. Among these Fusarium mycotoxins, the level of ZEN was surprisingly high. This is the first report on the natural occurrence of Fusarium mycotoxins in PNG cereals. © 1994 wiley‐Liss, Inc.
Interaction of dimethylsulfoxide and arachidonic acid with the teratogenic effects of caffeine in mice
Authors: Reedy Rajasekhar V. , Reedy Chada S. , Fraipier Brian L. , Brimer Gary E.
Published: October 2006

Dose‐response of the teratogenic effect of caffeine (CA) and the potential role of facial hematomas in the pathogenesis of caffeine‐induced cleft palate were investigated using CD1 mice treated with 150, 200, or 250 mg CA/kg i.p. on gestational day (GD) 12. Dimethylsulfoxide (DMSO; 20%) and arachidonic acid (AA, 200 mg/kg) were administered along with CA (200 mg/kg) to study their interaction with CA‐induced teratogenesis and elevation in maternal glucocorticoids (MGC, measured by RIA) on GD 13 and 14. Dose‐dependent increase in the incidence of cleft palate (CP) was noted in CA‐exposed mice. High maternal deaths, an increased number of resorptions, gross facial hematomas (GFH), and club foot (CF) were produced only by the highest (250 mg/kg) dose of CA. Palates from all offspring with GFH were clefted at this dose level. None of the control or CA‐treated nonclefted offspring had GFH or microscopic hematomas (MH). At 200 mg/kg of CA, DMSO in combination with CA actually increased CA‐induced CP from 30% to 100% and also produced 100% GFH as compared to 0% by CA alone at this dose. Greater than 50% of clefted offspring without GFH, given either dose (200 or 250 mg/kg) of CA, had MH. Very high levels of MGC were present in CA‐treated mice on GD 13 and 14. Although simultaneous administration of DMSO reduced the magnitude of CA‐induced MGC elevations on GD 14, the MGC levels remained high for greater than 24 hours following CA exposure. Increase in maternal mortality and fetal resorptions, a decrease in the number of live pups and their body weights, and no change in the incidence of CP were seen when CA‐treated mice were simultaneously exposed to AA. These results suggest a correlation between caffeine‐induced FH and CP; a role for increased hematomagenic effects of DMSO in its potentiation of the cleft‐palatogenic effect of caffeine; and absence of a role for AA‐mediated effects of MGC in the causation of CA‐induced CP and other malformations. © 1994 Wiley‐Liss, Inc.
Genetic relatedness of toxic and nontoxic isolates of the marine pennate diatom Pseudonitzschia (bacillariophyceae): Phylogenetic analysis of 18S rRNA sequences
Authors: Douglas Donald J. , Landry Denise , Douglas Susan E.
Published: October 2006

The nuclear small subunit (SSU) rRNA genes from several marine diatoms, including 2 species that have been responsible for toxic blooms, were amplified from total DNA by the polymerase chain reaction (PCR), and the sequences analyses to determine their genetic relatedness. The isolates investigated include 2 morphologically similar forms of the pennate diatom Pseudonitzschia pungens: (1) P. pungens f. multiseries, a known producer of the toxin domoic acid, and (2) P. pungens f. pungens, which is not toxic. Strains of a second toxin‐producing species, P. australis, and a nontoxic Thalassiosira species were also included in this study. Phylogenetic analyses of sequences by both distance and parsimony methods clearly distinguished the 2 forms of P. pungens and the 2 Pseudonitzschia species from other diatoms for which sequence data are available. Differences in the nucleotide sequences of the 2 forms of P. pungens permitted the design of PCR primers that allowed discrimination between them. This may prove a valuable tool in identifying toxic and nontoxic forms of closely related and morphologically similar diatom species. Published 1994 Wiley‐Liss, Inc.
Salt clean‐up procedure for the determination of domoic acid by HPLC
Authors: Hatfield Christine L. , Wekell John C. , Gauglitz Erich J. , Bamett Harold J.
Published: October 2006

Domoic acid (DA) was first reported in mussels from Prince Edward Island, Canada, in 1987. It reappeared in anchovies and pelicans from Monterey Bay, California, in 1991. Later that year, domoic acid was found in razor clams and Dungeness crabs along the Washington and Oregon coasts. Since the initial outbreak, a variety of analytical methods for the detection of this neurotoxin have been developed. Here, we describe a modification to the solid phase extraction (SPE) clean‐up step in Quilliam's HPLC‐UV method (1991: NRCC No. 33001). The standard 10% acetonitrile (MeCN) wash and 0.5M ammonium citrate buffer (ACB) in 10% MeCN (pH = 4.5) eluting solution have been replaced with a 0.1 M sodium chloride (NaCI) in 10% MeCN wash and a 0.5M NaCI in 10% MeCN eluting solution. This modification allows the analysis to work equally well on both clam and crab viscera and meat. Chromatograms of visceral samples no longer contain interfering or late eluting peaks; and all Chromatograms are free of the large solvent peak tailing associated with the ACB eluent. The newly modified method allows for an improved and more versatile domoic acid analysis. © 1994 Wiley‐liss, Inc.
Growth and toxin production of the toxic dinoflagellate Pyrodinium bahamense var. compressum in laboratory cultures
Authors: Usup Gires , Kulis David M. , Anderson Donald M.
Published: October 2006

Toxin production of a Malaysian isolate of the toxic red tide dinoflagellate Pyrodinium bahamense var. compressum was investigated at various stages of the batch culture growth cycle and under growth conditions affected by temperature, salinity, and light intensity variations. In all the experiments conducted, only 5 toxins were ever detected. Neosaxitoxin (NEO) and gonyautoxin V (GTX5) made up 80 mole percent or more of the cellular toxin content and saxitoxin (STX), GTX6 and decarbamoylsaxitoxin (dcSTX) made up the remainder. No gonyautoxins I‐IV or C toxins were ever detected. In nutrient‐replete batch cultures, toxin content rapidly peaked during early exponential phase and just as rapidly declined prior to the onset of plateau phase. Temperature had a marked effect on toxin content, which increased 3‐fold as the temperature decreased from the optimum of 28°C to 22°C. Toxin content was constant at salinities of 24%° or higher, but increased 3‐fold at 20%°. Toxin content decreased 2‐fold and chlorophyll content increased 3‐fold when light intensity was reduced from 90 to 15 μE m‐2 s‐1. This accompanied a 30% decrease in growth rate. Toxin composition (mole % individual toxin cell‐1) remained constant throughout the course of the nutrient‐replete culture and during growth at various salinities, but varied significantly with temperature and light intensity changes. At 22°C, GTX5 was 25 mole % and NEO was 65 mole %, while at 34°C, GTX5 increased to 55 mole % and NEO decreased proportionally to 40 mole %. When light intensity was reduced from 90 to 15 μE m‐2 s‐1, NEO decreased from 55 to 38 mole %, while GTX5 increased from 40 to 58 mole %. These data suggest that low light and high temperature both somehow enhance sulfo‐transferase activity. In general, toxin content and composition in P. bahamense were both influenced by factors that alter the growth rate of the species. The data show, however, that toxin content was not determined solely by growth rate but, more likely, by the manner in which the cells allocate their nitrogen and carbon to various cellular components and processes under various growth conditions. Several of the toxin production patterns observed in this P. bahamense isolate were similar to those of PSP toxin‐producing Alexandrium and Gyrnnodinium species, but there were also significant differences. © 1994 wiley‐Liss, Inc.