bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of metals in the enzymatic and nonenzymatic oxidation of epinephrine
Authors: Ryan Timothy P. , Miller Dennis M. , Aust Steven D.
Published: October 2006

The effects of transition metals on nonenzymatic and ceruloplasmin catalyzed epinephrine oxidation were investigated by studying rates of epinephrine oxidation in purified buffers and in the presence of metal chelating agents. We found that epinephrine does not “autoxidize” in sodium chloride solutions prepared with deionized water that was further purified by chromatography over Chelex 100 resin prior to use. Epinephrine was oxidized rapidly in sodium chloride prepared with tap water (1.20±0.12 nmoles/min) or in deionized water (0.40±0.80 nmoles/min), but this oxidation was prevented by the addition of Desferal, a potent metal chelating agent. Epinephrine oxidation was enhanced upon the addition of ceruloplasmin, and this oxidation rate could be slowed, but not eliminated, by the addition of Desferal. If epinephrine solutions were preincubated for 72 hours with Desferal prior to ceruloplasmin addition, however, no oxidation was observed. Epinephrine was shown to form colored complexes with both iron and copper at pH 7.0. The Fe(III)‐epinephrine complex was much more stable than was the Cu(II)‐epinephrine complex. Oxygen consumption studies of ceruloplasmin catalyzed epinephrine oxidation showed that copper was a better promoter of epinephrine oxidation than was iron, suggesting that ceruloplasmin‐catalyzed epinephrine oxidation results from adventitious copper bound to the purified enzyme. In light of these results, the physiological relevance of ceruloplasmin catalyzed oxidation of biogenic amines may be minor.
2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) alters pancreatic membrane tyrosine phosphorylation following acute treatment
Authors: Ebner Karl , Enan Fumio Matsumura Essam , Olsen Hugh
Published: October 2006

To understand the basic mechanisms of TCDD's action to cause hypoinsulinemia in several experimental animals, we have studied TCDD‐induced changes in various protein kinase activities in membrane preparations of guinea pig pancreas. For this purpose, young male guinea pigs were treated through a single intraperitoneal in jection with 1 or 3 μg/kg of TCDD in vivo, and, after given time periods, pancreas samples were obtained and membranes were isolated through homogenization and centrifugation procedures. Several sets of incubation conditions were selected for protein kinase activity assay, each favoring a specific type of protein kinase. It was found that overall protein phosphorylation activities were higher in the preparation from TCDD‐treated an imals as compared to those found in pair‐fed controls and that this trend was more pronounced when the assay medium contained Mn2+ in place of Mg2+ and EGTA. These are the conditions that are known to favor protein tyrosine kinases. Other types of protein kinases from the treated animals did not show any significant differences from the pair‐fed control animals, though that of protein kinase C in the treated preparation showed a modest increase. To establish that the type of protein kin ases stimulated by TCDD are protein tyrosine kin ases, we have carried out phosphoamino acid analyses, KOH digestion, and western blot analyses using an antibody to phosphotyrosine. All the results were consistent in supporting the idea that TCDD causes a rise in protein‐tyrosine kinases in pancreas at early stages of poisoning.
Toxicokinetics and biotransformation of pentachlorophenol in the topsmelt (Atherinops affinis)
Authors: Benner Diana B. , Tjeerdema Ronald S.
Published: October 2006

The toxicokinetics and biotransformation of pentachlorophenol (PCP) were determined in the topsmelt (Atherinops affinis) In a static system, topsmelt (n = 9) were exposed to 50 μg/L of [U‐14C]PCP for 24 hours to determine the absorption rate constant (Ka), the whole‐body bio‐concentration (at steady‐state conditions), the elimination rate constant UQ, and the elimination half‐life (t1/2). Kinetics were determined by direct quantitation of radioactivity in the exposure water. Following exposure, fish were placed in a flow‐through metabolism chamber for 24 hours to allow depuration of retained residues, which were collected on XAD‐4 resin. Excreted residues were identified and quantified by high‐pressure liquid co‐chromatography, fraction collection, and liquid scintillation counting. The Ka and Ke, calculated using a simplified model, were 0.012 M‐1 0.005/h and 0.014±;0.003/h, respectively, while the 24 hour total concentration factor was 278.0×182.0 and the t1/2 was 52.7±;11.2. During 24 hours of exposure to dean seawater, topsmelt depurated 32.9% of retained residues, and while PCP was primarily excreted unchanged (64.9%), significant amounts of both pentachlorophenylsulfate (18.9%) and pentachloro‐β‐D‐glucuronide (16.2%) were also formed.
Differential modulation of organophosphate‐sensitive muscarinic receptors in rat brain by parathion and chlorpyrifos
Authors: Chaudhuri J. , Chakraborti T. K. , Chanda S. , Pope C. N.
Published: October 2006

We previously reported similar levels of brain cholinesterase inhibition but marked differences in toxicity following acute maximum tolerated doses of the organophosphate pesticides parathion and chlorpyrifos. Because extensive acetylcholinesterase inhibition often induces compensatory changes in cholinergic receptor populations, we compared the effects of parathion and chlorpyrifos on brain muscarinic receptors. Adult male rats were treated with vehicle or the maximum tolerated dose of parathion (18 mg/kg, sc) or chlorpyrifos (279 mg/kg, sc) and observed for signs of acute toxicity. Similarly treated animals were sacrificed at 2, 7, or 14 days after treatment for measurement of cholinesterase activity and binding to the nonselective muscarinic antagonist [3H]quinuclidinyl benzilate, the M2‐preferential antagonist [3H]AFDX‐384, and the high‐affinity agonist [3H]cis‐methyldioxolane. More acute toxicity was noted after parathion treatment. Both insecticides caused similar levels (> 85%) of maximal cholinesterase inhibition and reductions (up to 55%) in atropine‐sensitive quinuclidinyl benzilate binding (i.e., total muscarinic receptors) and [3H]AFDX‐384 binding in cortex and striatum. Parathion also reduced, whereas chlorpyrifos increased, total muscarinic receptor binding and [3H]AFDX‐384 binding in the cerebellum. When tissues were preincubated with paraoxon (10 μM), radiolabeling of a subset of quinuclidinyl benzilate binding sites was blocked and the apparent densities of these organophosphate‐sensitive receptors in all three tissues were decreased (16% maximal) by parathion but increased (up to 37%) by chlorpyrifos. Similarly, parathion decreased whereas chlorpyrifos increased [3H]cis‐methyldioxolane binding sites in all three brain regions. We propose that differential modulation of these organophosphate‐sensitive muscarinic receptors contributes to differences in acute toxicity following exposure to these pesticides.
Dietary supplementation with taurine and niacin prevents the increase in lung collagen cross‐links in the multidose bleomycin hamster model of pulmonary fibrosis
Authors: Blaisdell Robert J. , Schiedt Mary J. , Giri Shri N.
Published: October 2006

Taurine and niacin have been previously found to block the accumulation of collagen in lung in the multidose bleomycin hamster model of pulmonary fibrosis. Previous studies have found an increase in the pulmonary collagen cross‐links dihydroxylysinonoroleucine (DHLNL) and hydroxypyridinium (OHP) in the single dose bleomycin rat model. In this study, we asked if taurine and niacin would block the increase in DHLNL and OHP in the multidose bleomycin hamster model of lung fibrosis. Hamsters were intratracheally instilled with three consecutive doses of saline or bleomycin sulfate 1 week apart (2.5, 2.0,1.5 units/ 5 mL/kg). Animals were fed diet containing either 2.5% niacin and 2.5% taurine or control diet throughout the experiment. The four groups were saline‐instilled with control diet (SCD), bleomycin instilled with control diet (BCD), bleomycin‐instilled with taurine‐niacin in diet (BTN), and saline‐instilled with taurine‐niacin in diet (STN). Animals were sacrificed at 1, 4, and 8 weeks after the last bleomycin instillation. Hydroxyproline per lung in the BCD group was significantly elevated by 38, 56, and 60% over the SCD group at 1, 4, and 8 weeks, respectively. There were no statistically significant differences among the four groups in DHLNL (mmole) per mole collagen at the 1 or 8 week time point. At four weeks, DHLNL was significantly elevated by 46.4% in the BCD group over the SCD group. The OHP (mmole) per mole of collagen at 1 and 4 weeks in the BCD group was not statistically different from the SCD group. However, at 8 weeks, this was significantly elevated by 31.4% over the SCD group. The DHLNL and OHP contents per mole of collagen were increased in the multidose bleomycin hamster model. Treatment with taurine and niacin in combination prevented the bleomycin‐induced increases in the DHLNL and OHP contents of the lung collagen and this may be one of the mechanisms for their antifibrotic effect in this multidose bleomycin hamster model of pulmonary fibrosis.
Partial characterization of neuropathy target esterase and related phenyl valerate esterases from bovine adrenal medulla
Authors: Sogorb M. A. , Viniegra S. , Reig J. A. , Vilanova E.
Published: October 2006

The mechanism by which organo‐phosphorus‐induced delayed polyneuropathy is induced relates to the specific inhibition and subsequent modification (“aging”) of a protein known as neuropathy target esterase (NTE), operatively defined as paraoxon‐resistant and mipafox‐sensi‐tive phenyl valerate (PV) esterase activity. This protein has fundamentally been investigated in hen brain, the latter being the habitually employed OPIDP study model. In the present article, a partial characterization is made of the NTE and other related PV esterases in the bovine adrenal medulla and brain; NTE sensitivity to the neurotoxic or‐ganophosphorus compound mipafox is investigated, and its subcellular distribution is studied. The NTE activity of the adrenal medulla was found to be the highest of those among the tissues studied to date (5000 ± 1400 mU/g tissue; ± SD, n = 12). This activity represented 93% of the PV esterase activity resistant to 40 μm paraoxon in the par‐ticulate fraction of the adrenal medulla and approximately 50% of total PV esterase activity. In the bovine brain, these proportions were 72 and 26%, respectively, i.e., similar to those described in hen brain. The mipafox inhibition curve of PV esterase activity resistant to 40μM paraoxon in the particulate fraction of the adrenal medulla suggests that NTE activity fundamentally comprises a mipafox‐sensitive component with an I 50 of 6.39 μM at 30 minutes, which is similar to the value reported in hen brain. NTE activity in the bovine adrenal medulla is almost exclusively limited to the particulate fraction, the microsomal fraction, plasma membrane, and chromaffin granule‐enriched fractions being the highest in terms of specific activity. On the contrary, the mitochondria‐enriched fraction was very poor in such activity. In bovine brain, most NTE activity was likewise limited to the particulate fraction.
Comparative kinetic study of the binding between 2,3,7,8‐tetrachlorodibenzo‐ρ‐dioxin and related ligands with the hepatic Ah receptors from several rodent species
Authors: Nakai Jamie S. , Winhall Martha J. , Bunce Nigel J. , Rosengren Rhonda , Safe Stephen
Published: October 2006

Kinetic analysis of the time course of association of [3H]‐2,3,7,8‐tetrachlorodibenzo‐ρ‐dioxin with hepatic cytosoi from five rodent species gave additional evidence for differences in the properties of the Ah receptor ligand binding subunit between species. A parallel study of the association of six tritiated polychlorinated dibenzopρ‐dioxins and dibenzofurans with hepatic Ah receptor from Wistar rat and C57BL/6 mouse showed that their rank order for kinetic affinity did not correlate with the rank ordering of their toxic potency‐ and may vary according to the source of the Ah receptor.
Arachidonic acid release in renal proximal tubule cell injuries and death
Authors: Schnellmann Rick G. , Yang Xiaonian , Carrick Joan B.
Published: October 2006

Arachidonic acid release and the effect of phospholipase inhibitors on various types of cell injuries and death to rabbit renal proximal tubule suspensions were determined. Proximal tubules were exposed to the mitochondrial inhibitor antimycin A (0.1 μM), the protonophore carbonyl cyanide ρ‐trifluoromethoxypheitylhydrazone (1 μM FCCP), the oxidant tertbutyl hydroperoxide (0.5 mM TBHP), or the calcium ionophore ionomycin (5 μM) in the absence or presence of the putative phospholipase inhibitors dibucaine, mepacrine, chlorpromazine, or U‐26384. The phospholipase inhibitors had no effect on the proximal tubule lactate dehydrogenase (LDH) release (a marker of cell death) produced by FCCP, antimycin A, or ionomycin after 1,2, or 2 hours of exposure, respectively. Only dibucaine and mepacrine decreased LDH release in TBHP‐treated proximal tubules without decreasing TBHP‐induced lipid peroxidation. Antimycin A and ionomycin did not release arachidonic acid from proximal tubules prelabeled with [1‐14C] arachidonic acid. In contrast, TBHP released arachidonic acid from proximal tubules prior to the onset of cell death, and dibucaine and mepacrine decreased the TBHP‐induced release. Thus, phospholipase inhibitors were cytoprotective in those injuries that produced arachidonic acid release. These results suggest that arachidonic acid release and phospholipase A2 activation play a contributing role in oxidant‐induced renal proximal tubule cell injury and death but not in mitochondrial inhibitor‐ or calcium ionophore‐induced proximal tubule cell injury and death.
Toxicology of cupric salts on honeybees IV — gluconate and sulfate action on hemolymph trehalose activity in vivo and in vitro
Authors: Nectoux M. , Bounias M. , Popeskovic D.
Published: October 2006

A biphasic increase of hemolymph glucose levels was observed following injection to bees of cupric gluconate or sulfate, both potent agents for the control of Varroa jacobsoni, a parasitic mite of hives. The simultaneous injection to bees of 0.3 μM BAYg5421 (an inhibitor of α‐glucosidases) quenched the response, suggesting a direct effect of 2 nmol/bee cupric ions on trehaloses' activity. One nanomol of injected cupric gluconate increased the trehalose (Tre) activity by 233% in crude hemolymph extracts at 1 mM trehalose concentration, and exhibited biphasic dose‐related effects with a maximum 15% increase at 0.5 mM cupric ion and a stabilized 20% inhibition from 4 mM, regardless of the anionic moiety. Upon partial purification of the enzyme complex, two fractions (FI = 75% and FII = 25% of total activity) were isolated that exhibited, respectively, less and more marked positive cooperativity than crude extract. Form I showed almost no susceptibility to either cupric derivatives, which indicated form II as the most likely target, with 68% and 72% increases with 0.25 mM cupric sulfate and 0.5 mM cupric gluconate, in presence of 16 mM trehalose.
Nucleotide changes in oxidatively stressed lymphocytes
Authors: Palace Gerard P. , Lawrence David A.
Published: October 2006

Similar to HIV‐1‐induced suppression of thymus‐derived lymphocytes (T cells), oxidatively stressed T cells show inhibited DNA synthesis and proliferation. The influence of oxidative stress on nucleotide pools was explored using 3H‐uridine addition to OKT3‐stimulated peripheral blood lymphocytes. The cells were preincubated and stimulated in the presence of 1 mM buthionine sulfoximine to inhibit GSH synthesis. This treatment gave rise to a significant reduction in dUDP and TTP biosynthesis following 18–32 hours stimulation, indicating possible impairment of ribonucleotide reductase activity.
Characterization of the Ah receptor from human placental tissue
Authors: Nakai Jamie S. , Bunce Nigel J.
Published: October 2006

The rate of thermal inactivation of the unliganded human Ah receptor, studied by sucrose density gradient centrifugation, with respect to loss of ligand binding ability, was found to be greater than those of most rodents at 20°C, but the temperature coefficient of the rate constant was much smaller than for the rodent species. This implies that the unliganded human Ah receptor would be thermally more stable than the rodent analogs at physiological temperatures. The liganded form of the human Ah receptor was found to be less stable with respect to ligand release than the rodent receptors. These differences in behavior between human and rodent Ah receptors underline the difficulties in using rodent data in the development of receptor‐based models of dioxin toxicity. Attempts to develop an alternative to sucrose density gradient centrifugation, comparable with the hydroxylapatite adsorption method used to assay rodent hepatic Ah receptor, were unsuccessful.
Mechanism of antifibrotic effect of taurine and niacin in the multidose bleomycin‐hamster model of lung fibrosis: Inhibition of lysyl oxidase and collagenase
Authors: Blaisdell Robert J. , Giri N.
Published: October 2006

In the multiple‐dose bleomycin‐hamster model of pulmonary fibrosis, combined treatment with taurine and niacin blocks the increase in lung collagen deposition. We investigated the effects of taurine and niacin on lung lysyl oxidase and type I collagenase activities in this model. Hamsters were intratracheally instilled with three weekly doses of saline or bleomycin sulfate. Animals were fed either a diet containing 2.5% niacin and 2.5% taurine, or a control diet throughout the experiment. The four groups were saline‐instilled with the control diet (SCD), bleomycin‐instilled with control diet (BCD), bleomycin‐instilled with the diet containing taurine and niacin (BTN), and saline‐instilled with the diet containing taurine and niacin (STN). Animals were sacrificed at 1, 4, and 8 weeks after the last bleomycin instillation. Hydroxyproline per lung in the BCD group was significantly elevated by 38, 56, and 60% over the SCD group at 1, 4, and 8 weeks, respectively. Lysyl oxidase activity per lung in the BCD group was significantly elevated by 57.5 and 91.4% over the SCD controls at 1 and 4 week time periods, respectively. Type I collagenase activity per lung in the BCD group was significantly elevated by 65 and 80% over the SCD controls at 1 and 4 weeks, respectively. The combined treatment with taurine and niacin abolished the bleomycin‐induced increases in the lung hydroxyproline content and lysyl oxidase and collagenase activities. It was postulated that one of the mechanisms for the antifibrotic effect of taurine and niacin may be the blockage of bleomycin‐induced increases in the lung lysyl oxidase and collagenase activities. © 1995 John Wiley & Sons, Inc.
Organophosphorus inhibition and heat inactivation kinetics of particulate and soluble forms of peripheral nerve neuropathy target esterase
Authors: Barril J. , Tormo N. , Diaz‐Alejo N. , Vilanova E.
Published: October 2006

Neuropathy target esterase (NTE) is the proposed target site for the mechanism of initiation of the so‐called organophosphorus‐induced delayed polyneuropathy (OPIDP). NTE is operationally defined in this article as the phenylvalerate esterase activity which is resistant to inhibition by 40 μM paraoxon and sensitive to 250 μM mipafox. Soluble (S‐NTE) and particulate (P‐NTE) forms of NTE had first been identified in hen sciatic nerve [E. Vilanova, J. Barril, V. Carrera, and M. C. Pellín (1990). J. Neurochem., 55, 1258–1265]. P‐NTE and S‐NTE showed different sensitivities to the inhibition by several organophosphorus compounds over a range of inhibitor concentrations for a 30 or 120 minute fixed inhibition time at 37°C. S‐NTE was less sensitive to the inhibition by O,O′‐diisopropyl phosphorofluoridate (DFP), hexyl 2,5‐dichlorophenyl phosphoramidate (H‐DCP), and mipafox than P‐NTE and brain NTE, while the opposite was true for O,S‐dimethyl phosphoroamidothioate (methamidophos). For each of the four inhibitors assayed, S‐NTE showed two components of different sensitivity according to the inhibition curves fitted with exponential models. However, the inhibition of P‐NTE by mipafox, DFP, and HDCP did not show the presence of a considerable proportion of a second component. The kinetics of heat inactivation showed that P‐NTE inactivated faster and to a greater extent than S‐NTE. It is concluded that (1) sciatic nerve S‐NTE is more different from brain NTE than P‐NTE; (2) P‐NTE and S‐NTE have different sensitivities to the inhibition by the studied organophosphorous compounds; (3) the inhibition curves suggest that S‐NTE has two different enzymatic components while these are not so evident for P‐NTE. © 1995 John Wiley & Sons, Inc.
Chromium‐induced production of reactive oxygen species, DNA single‐strand breaks, nitric oxide production, and lactate dehydrogenase leakage in J774A.1 cell cultures
Authors: Hassoun E. A. , Stohs S. J.
Published: October 2006

The involvement of oxidative stress in the toxicity of chromium (VI) and chromium (III) has been proposed. We have therefore examined the effects of these cations on the production of superoxide anion, nitric oxide (NO), and DNA single strand breaks (SSB) in J774A.1 macrophage cells in culture as well as the effects on lactate dehydrogenase (LDH) leakage and cell viability. Following a 48 hour incubation, over twofold increases in superoxide anion and NO production were observed at concentrations of approximately 0.30 and 50 μM for Cr (VI) and Cr (III), respectively. The patterns of cell viability and LDH leakage paralleled superoxide anion and NO production for Cr (VI) and Cr (III). A 50% decrease in viability was observed at approximately the concentrations that produced a twofold increase in superoxide and NO production. Concentration‐dependent increases in DNA‐SSB were observed after incubation with Cr (III) with maximum increases occurring at a concentration of approximately 60 μM. Cr (VI) had no effect on the incidence of DNA‐SSB at any of the tested concentrations. The results indicate that Cr (VI) and Cr (III) are toxic to the J774A.1 cell line, and the toxicity may be due at least in part to an oxidative stress induced by the production of reactive oxygen species. © 1996 John Wiley & Sons, Inc.
Isolation from bovine liver mitochondria and characterization of three distinct carboxylic acid:CoA ligases with activity toward xenobiotics
Authors: Vessey Donald A. , Hu Jie
Published: October 2006

A mitochondrial freeze/thaw lysate was fractionated on a DEAE‐cellulose column into four distinct acyl‐CoA ligase fractions. First to elute was a 50 kDa short‐chain ligase that activated only short‐chain fatty acids. Next to elute were three ligases that had activity toward both medium‐chain fatty acids and xenobiotic carboxylic acids; these were termed xenobiotic/medium‐chain ligases (X‐ligases) and labeled XL‐I, XL‐II, and XL‐III, respectively, based on order of elution. The molecular weight of X‐ligases I, II, and III were ca. 55,000, 55,500 and 53,000, respectively. Form XL‐III showed no pH optimum; the rate increased steadily with pH beginning from pH 7.0. XL‐I and XL‐II showed the same behavior with benzoate as substrate, but with medium‐chain fatty acids, both forms had a pH optimum at 8.8. The three X‐ligases differed in substrate specificity. XL‐I was the predominant nicotinic acid activating form and had the lowest Km for benzoate. Form XL‐II was the only form with measurable salicylate activity, although it was extremely low. XL‐III was the only 2,4,6,8‐decatetraenoic acid activating form and also was the predominant medium‐chain fatty acid‐activating form. By comparison of substrate specificities, it was concluded that the two previously reported ligase preparations were mixtures of the three forms. When the ligase rates were compared to previously determined N‐acyltransferase rates toward benzoyl‐CoA and phenylacetyl‐CoA, the data showed that ligase activities are 100‐fold lower, and thus the ligase is rate limiting for the conjugation of both of these xenobiotics. © 1996 John Wiley & Sons, Inc.
Osteoderm morphology and development in the nine‐banded armadillo, Dasypus novemcinctus (Mammalia, Xenarthra, Cingulata)
Authors: Vickaryous Matthew K. , Hall Brian K.
Published: October 2006

Among modern mammals, armadillos (Xenarthra, Cingulata) are the only group that possesses osteoderms, bony inclusions within the integument. Along the body, osteoderms are organized into five discrete assemblages: the head, pectoral, banded, pelvic, and tail shields. The pectoral, banded, and pelvic shields articulate to form the carapace. We examined osteoderm skeletogenesis in the armadillo Dasypus novemcinctus using serial and whole‐mount histochemistry. Compared with the rest of the skeleton, osteoderms have a delayed onset of development. Skeletogenesis begins as condensations of osteoblasts secreting osteoid, localized within the papillary layer of the dermis. Osteoderm formation is asynchronous both within each shield and across the body. The first osteoderms to mineralize are situated within the pectoral shield of the carapace, followed by elements within the banded, head, pelvic, and tail shields. In general, within each shield ossification begins craniomedially and proceeds caudally and laterally, except over the head, where the earliest elements form over the frontal and parietal bones. The absence of cartilage precursors indicates that osteoderms are dermal elements, possibly related to the all‐encompassing vertebrate dermal skeleton (exoskeleton). The mode of development of D. novemcinctus osteoderms is unlike that described for squamate osteoderms, which arise via bone metaplasia, and instead is comparable with intramembranously derived elements of the skull. J. Morphol., 2006. © 2006 Wiley‐Liss, Inc.
Genome size and determination of DNA content of the X chromosomes, autosomes, and germ line‐limited chromosomes of Sciara coprophila
Authors: Rasch Ellen M.
Published: October 2006

The unique chromosome biology of the fungus fly Sciara coprophila has fascinated investigators for over 80 years. Male meiosis exhibits a monopolar spindle, nonrandom segregation of imprinted chromosomes and nondisjunction of the X chromosome. The unusual mechanism of sex determination requires selective elimination of X chromosomes in embryogenesis. Supernumerary (L) chromosomes are also eliminated from the soma during early cleavage divisions. Distinctive DNA puffs on the larval salivary gland chromosomes are sites of DNA amplification. As a foundation for future genome studies to explore these many unusual phenomena, we have used DNA‐Feulgen cytophotometry to determine genome size from hemocyte nuclei of male (X0) and female (XX) larvae and adults. The DNA content of the X chromosome is ∼0.05 pg DNA and the autosomal complement is ∼0.45 pg DNA. Measurements of DNA levels for individual sperm from adults showed that the DNA contribution of the germ line‐limited (L) chromosomes constitutes as much as 35% of the DNA of the male gamete. A parallel study using Sciara ocellaris, a related species lacking L chromosomes, confirmed the presence of two X chromosomes in the sperm of this species. J. Morphol., 2006. © 2006 Wiley‐Liss, Inc.
Determination of clavulanic acid in calf plasma by liquid chromatography tandem mass spectrometry
Authors: Reyns Tim , De Baere Siegrid , Croubels Siska , De Backer Patrick
Published: October 2006

A method for the quantification of clavulanic acid in calf plasma using high‐performance liquid chromatography combined with electrospray ionization (ESI) mass spectrometry, operating in the negative ionization mode (LC‐MS/MS), is presented. Sample preparation includes a simple and fast deproteinization with acetonitrile and a back‐extraction of the acetonitrile with dichloromethane. Chromatography is performed on a reversed‐phase PLRP‐S polymeric column using 0.05% formic acid in water and acetonitrile. The limit of quantification is 25 ng/ml, which is lower than other published methods using ultraviolet (UV), fluorimetric or mass spectrometric detection. The limit of detection is calculated to be 3.5 ng/ml. The stability of clavulanic acid was demonstrated according to The Guidelines of Bioanalytical Method Validation of The Food and Drug Administration (FDA): freeze and thaw stability, short‐term stability, long‐term stability, stock solution stability and postpreparative stability. The method is used in a pharmacokinetic and bioequivalence study of amoxycillin/clavulanic acid formulations in calves. Copyright © 2006 John Wiley & Sons, Ltd.
Hyphenated mass spectrometric techniques—indispensable tools in clinical and forensic toxicology and in doping control
Authors: Maurer Hans H.
Published: October 2006

Hyphenated mass spectrometric techniques, particularly gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS), are indispensable tools in clinical and forensic toxicology and in doping control owing to their high sensitivity and specificity. They are used for screening, library‐assisted identification and quantification of drugs, poisons and their metabolites, prerequisites for competent expertise in these fields. In addition, they allow the study of metabolism of new drugs or poisons as a basis for developing screening procedures in biological matrices, most notably in urine, or toxicological risk assessment. Concepts and procedures using GC/MS and LC/MS techniques in the areas of analytical toxicology and the role of mass spectral libraries are presented and discussed in this feature article. Finally, perspectives of their future position are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Intervention strategies to inhibit protein carbonylation by lipoxidation‐derived reactive carbonyls
Authors: Aldini Giancarlo , Dalle‐Donne Isabella , Facino Roberto Maffei , Milzani Aldo , Carini Marina
Published: October 2006

Protein carbonylation induced by reactive carbonyl species (RCS) generated by peroxidation of polyunsaturated fatty acids plays a significant role in the etiology and/or progression of several human diseases, such as cardiovascular (e.g., atherosclerosis, long‐term complications of diabetes) and neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, and cerebral ischemia). Most of the biological effects of intermediate RCS, mainly α,β‐unsaturated aldehydes, di‐aldehydes, and keto‐aldehydes, are due to their capacity to react with the nucleophilic sites of proteins, forming advanced lipoxidation end‐products (ALEs). Because of the emerging deleterious role of RCS/protein adducts in several human diseases, different potential therapeutic strategies have been developed in the last few years. This review sheds focus on fundamental studies on lipid‐derived RCS generation, their biological effects, and their reactivity with proteins, with particular emphasis to 4‐hydroxy‐trans‐2‐nonenal (HNE)‐, acrolein (ACR)‐, malondialdehyde (MDA)‐, and glyoxal (GO)‐modified proteins. It also discusses the recently developed pharmacological approaches for the management of chronic diseases in which oxidative stress and RCS formation are massively involved. Inhibition of ALE formation, based on carbonyl‐sequestering agents, seems to be the most promising pharmacological tool and is reviewed in detail. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 6, 817–868, 2007
Multilingual digital libraries: Research and practice
Authors: Zhang Yin , Oard Douglas , Howarth Lynne , Witten Ian H.
Published: October 2006

This session focuses on important issues in designing and implementing multilingual digital libraries. A group of experts who have both research and implementation experiences with multilingual digital libraries will join the panel to present and discuss: (1) the state of the art of searching a broad range of spoken word multilingual digital collections, (2) research and development of a multilingual cross‐repository retrieval prototype, and (3) implementation of an open source digital library system that supports creating multilingual digital libraries.
From spam filtering to information retrieval and back: Seeking conceptual foundations for spam filtering
Authors: Lueg Christopher P.
Published: October 2006

Email filters removing or tagging messages suspected to be “spam” have become ubiquitous. Presumably, spam filters identify spam messages but a closer look at the filtering process suggests there is a conceptual gap between user‐referential definitions of spam (“unsolicitedemail”) developed in relevant discourse and (often implicit) definitions of spam operationalized by spam filters. In this contribution we outline the gap and explore whether information filtering and information retrieval terminology could be used to conceptualize spam filtering in a systematic, theoretically grounded way, thus helping introduce spam filtering terminology that could be operationalized in a meaningful way.
Annotating the Web: An exploratory study of Web users' needs for personal annotation tools
Authors: Fu Xin , Ciszek Tom , Marchionini, Gary , Solomon Paul
Published: October 2006

This exploratory study investigates the needs Web users have to make annotations for their personal use when they view Web pages. Three forms of annotations observed on printed documents ‐ text selection and emphasis, association building, and document re‐segmentation ‐ are examined in the Web environment. The study shows that text selection and association building through notes or symbols remain the dominant forms of annotation on the Web, while structural annotation (re‐segmentation) and layout annotation (change of font, color, etc.) are also prevalent. The study also investigates users' preferences for the tools designed to facilitate Web annotation practices. Findings suggest that usability is of utmost importance when developing Web annotation tools, and that under the current technical conditions, users welcome lightweight annotation functions, which are built into standard Web browsers.
Lost in translation? Applying information behavior research to information systems design
Authors: Burton‐West Tom , Vondracek Ruth , Erdelez Sanda , Hendry David G. , Hirsh Sandra , Marchionini Gary
Published: October 2006

Information seeking and use research generates numerous results on how users approach systems. Why then does it seem that something is lost in translation between research results and systems design? Panelists will discuss their experiences with incorporating the findings of information behavior research in system design. This panel focuses on the gap between the research on information seeking and use and its applications to systems design. Panelists from industry and academia will address the following issues:

Why is there a gap between research and design practice? How can that gap be characterized?

What are the obstacles to applying information behavior research to system design? How can these be overcome?

What is the role of information behavior research in development projects? Howe can research results more effectively benefit design?

How can researchers become more involved in influencing design?

What is needed to improve communication between information behavior researchers and others involved in the design of information systems?

How can systems designers, vendors, and librarians who purchase and customize commercial and open source information systems address these issues?
Developing multi‐method, iterative, and user‐centered evaluation strategies for digital libraries: Functionality, usability, and accessibility
Authors: Snead John T. , Bertot John Carlo , Jaeger Paul T. , McClure Charles R.
Published: October 2006

Usability, functionality, and accessibility testing of digital library information services and products are essential for providing high quality services to users. This paper details a long‐term, evolving effort to develop meaningful evaluations for assessing digital libraries. The authors of this paper have been engaged in a multi‐year study to determine appropriate evaluation techniques, tools, and methodologies for the Florida Electronic Library (FEL) and other digital libraries. The evaluation protocols and approaches have been designed over time and iteratively through assessment efforts of the research team of other digital library initiatives and with multiple versions of the FEL. As such, this paper examines the process of developing, applying, and refining appropriate evaluation methodologies for the networked environment of libraries, as well as the implications of these methodologies.

The approach taken in the research described herein relies on a combination of evaluation strategies applied iteratively to assess libraries from the perspective of patron needs. A number of specific methods, as shown in this paper, can be readily developed to provide such evaluations. The following goals guide the presentation in this paper of the development through time of the methods and instruments created, tested, refined, and operationalized in functionality, usability, and accessibility testing by the researchers. The goals of this paper are to: 1) demonstrate the potential roles of multiple, iterative evaluation strategies in the development and refinement of digital libraries; 2) detail the methodologies that focus on how the services meet the needs of users; and 3) encourage further discussion of the uses of these multiple evaluation approaches in assessing these libraries.
Modeling the information behaviour of software engineers using a work ‐ task framework
Authors: Freund Luanne , Toms Elaine G. , Waterhouse Julie
Published: October 2006

Faced with the rapid proliferation of digital information resources within organizations, employees need targeted search systems in order to be effective in their jobs. The goal of this study is to develop a model of information behaviour within a work‐task framework that can be used to inform the design of a workplace information search system. In a two‐phase process, we conducted a series of studies using multiple methods to identify workplace characteristics and to understand how they influence the needs, search strategies, and information sources used by software engineers working as services consultants in a large high‐tech company.
Going beyond counting first authors in author co‐citation analysis
Authors: Zhao Dangzhi
Published: October 2006

The present study examines one of the fundamental aspects of author co‐citation analysis (ACA) ‐ the way co‐citation counts are defined. Co‐citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co‐citation counting ‐ the traditional type that only counts the first one among a cited work's authors on the one hand and a non‐traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non‐traditional author co‐citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first‐author co‐citation counting when the same number of top‐ranked authors is selected and analyzed. Reasons for these effects are discussed.
RoMEO Green at the University of Kansas: An experiment to encourage interest and participation among faculty and jump start populating the KU scholarworks repository
Authors: Mercer Holly , Emmett Ada
Published: October 2006

Universities around the world are beginning to develop digital repositories in order to offer new methods for the distribution and preservation of the intellectual output of their faculty. The University of Kansas (KU) is among these universities and is exploring ways to provide better access to and preservation of published and unpublished scholarly research created by KU faculty. The University's institutional repository, KU ScholarWorks (http://kuscholarworks.ku.edu/), entered into production in October 2004 with participation from selected departments and research centers and opened to all faculty early in 2005.

While the expectation is that faculty will self‐archive their submissions through a departmental community structure, we initiated a project, RoMEO Green, to explore other staff‐mediated options for content recruitment. This paper will address the steps taken thus far to populate the repository through this alternative process, the data collection methods, and early findings during the data analysis phase. We will discuss possible implications of these results for future directions of this project and for the larger mission of KU ScholarWorks. Project findings may be of interest to institutions considering different models for populating institutional repositories.
Finding pleasure in information seeking: Leisure and amateur genealogists exploring their Irish ancestry
Authors: Fulton Crystal
Published: October 2006

Genealogy may be characterized as serious leisure, that is an amateur or voluntary activity in which the hobby forms a central life interest, with participants actively acquiring and expressing special skills, knowledge and experience (Stebbins, 1996; 1997). Information skills development and information exchange are key features of genealogy. Amateur genealogists are very often older adults who have time to devote themselves to learning information and technical skills needed to navigate the complex maze of resources that support this activity.

This paper explores the information seeking behaviour of amateur genealogists in their leisure. Amateur genealogists from around the world participated in telephone interviews about their hunt for their Irish ancestors. Data were analyzed to identify patterns of communication and links between and among amateur genealogists, groups, and resources. Findings reveal that amateur genealogists are a unique group of information seekers, who devote their spare time to information seeking and sharing among like‐minded researchers. Findings suggest that leisure time is an important information seeking context, in which people relate information seeking with pleasure, as opposed to a work‐related or routine life information need.
Meeting the demands of digital scholarship: Challenges and opportunities
Authors: Alemneh Daniel Gelaw , Hartman Cathy Nelson , Hastings Samantha Kelly
Published: October 2006

The synergies of numerous emerging trends such as the development of open standards and open source software, geometric growth of blogs and podcasts, peer‐to‐peer networking, cross discipline collaborations, etc. provide new directions for scholarship. Likewise, digital libraries and supporting technologies have now matured to the point where their contents are incorporating complex and dynamic resources and services. Powered by network capability and fuelled by digital developments, research is becoming more data intensive in almost every discipline. The rapid pace of development poses new threats and problems. Many of these innovations, for example, may have come at the expense of simplicity, sustainability, and other commonly understood applications in the life cycle management of digital resources. Based on the University of North Texas Libraries' “Portal to Texas History” implementation experiences, this paper provides a general overview on the emerging trends and innovative usage of digital library technologies. This paper provides an overall scenario in the areas of aggregating a variety of digital formats; deploying, maintaining, and archiving digital contents; and other innovative uses of digital library technologies.
The effect of document readability on perceived familiarity and relevance
Authors: Muresan Gheorghe , Liu Lu , Cole Michael , Smith Catherine L. , Belkin Nicholas J.
Published: October 2006

We report on an evaluation of the relationship between document readability, an objective measure related to the length and complexity of words and sentences, and the subjective perception of document relevance of users with a certain level of familiarity to a topic.

The research reported here, follow‐up work to our TREC2004effort, tries to explain why all our TREC hypotheses were rejected. While trying to understand what was wrong with our intuition, we propose and test new hypotheses.

The main conclusion is that readability may improve the chances that a document is judged relevant, which suggests the use of “blind readability feedback”, i.e. boosting the ranking of relevant documents when performing a search in order to improve retrieval performance.
Blogs as a means of preservation selection for the World Wide Web
Authors: Gouge Marianne K.
Published: October 2006

Currently, there is not a strong system of selection in place when looking at preserving content on the Web. This study is an examination of the blogging community for the possibility of utilizing the decentralized and distributed nature of link selection that takes place within the community as a means of preservation selection. The purpose of this study is to compare the blog aggregators, Daypop, Blogdex, and BlogPulse, for their ability to collect content which is of archival quality. This study analyzes the content selected by these aggregators to determine if any content which is linked to most frequently for a given day is of archival quality. Archival quality is determined by comparing the content from the aggregator lists to criteria assembled for the study from a variety of archival policies and principles.
Reports of the demise of the "user" have been greatly exaggerated: Dervin's sense‐making and the methodological resuscitation of the user – looking backwards, looking forward
Authors: Dervin Brenda , Fisher Karen E. , Durrance Joan , Ross Catherine , Savolainen Reijo , Solomon Paul
Published: October 2006

In 2003, an ASIST panel (Rosenbaum, Davenport, Lieuvrouw, Day, 2003) pronounced the "death of the user" suggesting that new technologies undermine a concept that was already weak in ability to account for agency in information seeking and use. This panel challenges that pronouncement by addressing how methodological approaches have created users in different manifestations – emotional, cognitive, physical, and social – elusive and capricious, dead or almost so, overly demanding, disinterested, individualistic, materialistic, culture‐bound, active, passive…. Panelists zero in on how they have used and struggled with Dervin's Sense‐Making Methodology (Dervin & Foreman‐Wernet, 2003) in attempts to conduct parsimonious, heuristic, and useful user studies and to introduce a strong user‐orientation into LIS pedagogy and practice. Starting with the seminal Dervin & Nilan (1986) ARIST review of information seeking and use studies, Dervin's Sense‐Making has been pointed to as sparking the turn toward user‐oriented studies of information seeking and use (e.g., Savolainen, 1993). Sense‐Making has been much quoted and misquoted, praised and criticized, implemented and co‐opted. This panel will look backwards and forward using Sense‐Making as an exemplar and foil for considering the ways philosophies that drive methodologies and methods that implement them enlarge or diminish our conceptions of the user.
Finding documents in a digital institutional repository: DSpace and Eprints
Authors: Kim Jihyun
Published: October 2006

Institutional repositories are “digital collections that capture and preserve the intellectual output of universities” (Crow, 2002). While still in their initial stages of development, much attention has been paid to the technical and administrative components. This paper examines the usability of the interfaces of two of the most commonly used institutional repository systems: DSpace and Eprints. By using heuristic evaluation and usability testing, eighteen undergraduate students were tested using a between subjects experimental design. Measures included time for completing tasks, the number of errors, and users' satisfaction from post‐test questionnaires. Results of the study indicated that DSpace users spent less time completing tasks and made fewer errors than Eprints users. Overall satisfaction of DSpace was also higher than Eprints. Based on this analysis of problem areas, the study suggests guidelines for institutional repository interfaces.