bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamics of local expansion by an introduced species: Pterostichus melanarius Ill. (Coleoptera, Carabidae) in Alberta, Canada
Authors: Niemelä Jari , Spence John R. 
Published: March 2003

SummaryA recently established population of Pterostichus melanarius Ill., a wing‐dimorphic, introduced carabid beetle species, was studied over a 7‐year period in Alberta, Canada. We monitored local colonization, and tested classical hypotheses about spatial and temporal changes in proportion of flight‐wing morphs in the Carabidae. Between 1991 and 1997, a sizable population in a road verge (0.17 individuals/trap/day in 1991) expanded only slowly into an adjacent aspen‐poplar forest: the catch of 0.005 ind./trap/day in the forest in 1997 was not significantly higher than that of 0.001 ind./trap/day in 1991. However, a significantly higher proportion of P. melanarius were macropterous, long‐winged (LW) in the forest (80%) than in the road verge and at the forest edge (54%). This supports the hypothesis that newly established populations are characterized by a high proportion of LW individuals, and further indicates that dispersal from the road verge into the forest has taken place primarily through flight. The overall proportion of flightless, brachypterous individuals (SW) captured at the study site increased from 39% in 1991 and 1992 to 57% in 1997, supporting the hypothesis that the proportion of SW individuals will increase with time since establishment of a population. Captures of P. melanarius in the forest were patchy and concentrated in particular areas throughout the study. However, these bridgehead’ populations did not grow or expand obviously, suggesting that populations adapt to forest conditions or reach some threshold size before effective expansion.
Understanding regional species diversity through the log series distribution of occurrences
Authors: Buzas Martin A. , Culver Stephen J. 
Published: March 2003

SummaryThe distribution of benthic foraminifera around the continental margins of North America is extensively documented. Data from 2673 localities consists of a synonomized list of 2329 species (S) and 61 369 occurrences (n). Here, the margins are divided into five geographical regions: Pacific (PA), S=965, n=19 014; Arctic (AR), S=458, n=7342; Atlantic (AT), S=878, n=10 034; Gulf of Mexico (GM), S=849, n=18 011; Caribbean (CR), S=1188, N=6968. As for many other organisms, species richness is lowest in the Arctic and highest in the Caribbean. In each region, the distribution of species richness and occurrences is a log series. Consequently, the entire series of species occurrences is predicted by the single proportionality constant, α. After log series rarefaction, differences in species richness among areas are nearly all accounted for by species occurring ≤10 times. Most of the differences are accounted for by species occurring once, less by twice, and so on. For example, species occurring once account for 81% of the difference in species richness between the Atlantic and Caribbean, and those occurring once and twice account for 87% of the difference. Most rare species have no fossil record and most endemic species are rare. Probably most of these species evolved recently indicating more origination in species‐rich areas. High origination might also be coupled with less extinction. Although each of the five regions can easily be distinguished by differences in composition, in all regions the 10 most abundantly occurring species exhibit nearly equal proportions of occurrences. No region is dominated by only one or two species. All regions exhibit the log series distribution, have nearly equal proportions for abundant species, and differ only in the number of rare species that coexist. Thus, from the point of view of the distribution of occurrences, the most striking aspect is the similarity among regions.
A pragmatic approach to estimating the distributions and spatial requirements of the medium‐ to large‐sized mammals in the Cape Floristic Region, South Africa
Authors: Boshoff A. F. , Kerley G. I. H. , Cowling R. M. 
Published: March 2003

Abstract.Conservation planning in the Cape Floristic Region, a recognized world plant diversity hotspot, required systematic information on the estimated distributions and spatial requirements of the medium‐ to large‐sized mammals within each of 102 Broad Habitat Units delineated according to key biophysical parameters. As a consequence of a general lack of data, we derived a pragmatic approach for obtaining estimates of these two parameters. Distribution estimates were based on a combination of a literature survey (with emphasis on early texts) and the ecological requirements of the species. Spatial requirement estimates were derived from a simple spreadsheet model that is based on forage availability estimates and the metabolic requirements of the mammals in question. Our analysis incorporated adaptations of the agriculture‐based Large Stock Unit or Animal Unit approach. The predictions of the model were tested by comparing them with actual density data. The outcomes provided realistic estimates of the two parameters. However, they should be considered as testable hypotheses and the concept of adaptive management — or management by hypothesis — must apply. Examples of the outcomes are provided in the form of maps and tables.
Spatial, environmental and human influences on the distribution of otter (Lutra lutra) in the Spanish provinces
Authors: Barbosa Ana Márcia , Real Raimundo , Márquez Ana Luz , Rendón Miguel Ángel 
Published: March 2003

AbstractIn a previous survey of otters (Lutra lutra L. 1758) in Spain, different causes were invoked to explain the frequency of the species in each province. To find common causes of the distribution of the otter in Spain, we recorded a number of spatial, environmental and human variables in each Spanish province. We then performed a stepwise linear multiple regression of the proportion of positive sites of otter in the Spanish provinces separately on each of the three groups of variables. Geographic longitude, January air humidity, soil permeability and highway density were the variables selected. A linear regression of the proportion of otter presence on these variables explained 62.4% of the variance. We then used the selected variables in a partial regression analysis to specify which proportions of the variation are explained exclusively by spatial, environmental and human factors, and which proportions are attributable to interactions between these components. Pure environmental effects accounted for only 5.5% of the variation, while pure spatial and pure human effects explained 18% and 9.7%, respectively. Shared variation among the components totalled 29.2%, of which 10.9% was explained by the interaction between environmental and spatial factors. Human factors explained globally less variance than spatial and environmental ones, but the pure human influence was higher than the pure environmental one. We concluded that most of the variation in the proportion of occurrences of otter in Spanish provinces is spatially structured, and that environmental factors have more influence on otter presence than human ones; however, the human influence on otter distribution is less structured in space, and thus can be more disruptive. This effect of large infrastructures on wild populations must be taken into account when planning large‐scale conservation policies.
Subpopulations ofCryptocephalusbeetles (Coleoptera: Chrysomelidae): geographically close but genetically far
Authors: Piper R. W. , Compton S. G. 
Published: March 2003

Abstract.The leaf beetlesCryptocephalus coryli, C. decemmaculatusandC. nitidulusare of conservation concern and are included on the UK Biodiversity Action Plan. The distinctiveness of the disjunct remaining populations of these beetles was compared to that of more continuously distributedCryptocephalusspecies. This was carried out with a view to defining evolutionary significant units (ESUs) in the rare species. A portion of the cytochromebgene, an intergenic spacer and partial tRNA was analysed from 93 specimens ofCryptocephalusbeetle (Coleoptera: Chrysomelidae). Considerable sequence divergence was apparent in all the species, even at an intersite scale when the distances between sampled localities were very small (< 1 km). Intrapopulation, intersite and interpopulation divergence observed in the rare species was reflected in the species that have a more continuous distribution, implying that dispersal ability in these species is poor and gene flow can be impeded by relatively trivial barriers to dispersal. The evidence suggests that the disjunct populations of the rareCryptocephalusspecies can, tentatively, be considered as ESUs. This has important implications for management strategies and reintroductions.
The effect of pentoxifylline on intestinal ischemia/reperfusion injury
Authors: Şener  , Akgün  , Şatıroğlu  , Topaloğlu  , Keyer‐Uysal  
Published: March 2003

The small intestine is highly sensitive to oxygen free radical‐induced injury. Post‐ischemic intestinal tissue damage appears to be due to the formation of oxygen radicals. Free radical initiated lipid peroxidation (LP) following intestinal ischemia/reperfusion (I/R) may disrupt mucosal integrity. Indirectly, the radicals trigger the accumulation of neutrophils within the affected tissue, initiating inflammatory processes that lead to severe mucosal lesions.In the present study we investigated the effect of pentoxifylline (PTX), a potent inhibitor of tumour necrosis factor production, on I/R induced intestinal injury. Wistar albino rats were divided into four groups: (1) Sham operation (S); (2) Sham operation + PTX (50 mg/kg i.v.) (S + PTX); (3) 1 h ischemia + 2 h reperfusion (I/R); and (4) I/R + PTX. Animals were sacrificed at the end of the reperfusion period and ileum samples were obtained. Malondialdehyde (MDA) levels, an end product of LP, glutathione (GSH) levels, a key antioxidant, and myeloperoxidase (MPO) activity (an index of polymorphonuclear neutrophils) stimulation, were determined in ileum homogenates.The results of the present study indicate that ischemia/reperfusion results in a significant increase in MDA content and MPO activity with a significant decrease in GSH content. Treatment with PTX returns these biomarkers to control values. A mechanism of this protective effect may involve inhibition of neutrophil oxidative burst.
Vascular reactivity to angiotensin II alone or combined with a thromboxane A2 mimetic in the isolated perfused kidney of Lyon hypertensive rats
Authors: Oréa Valérie , Liu Kiao Ling , Benzoni Daniel 
Published: March 2003

The aim of this study was to evaluate whether thromboxane A2‐prostaglandin H2 (TP) receptor activation potentiates the renal vasoconstrictor effect of Angiotensin II (Ang II) in genetically hypertensive rats of the Lyon strain (LH). Concentration‐response curves (CRCs) to Ang II (5 pM to 10 nM), to the specific TP receptor agonist U46619 (7.5–960 nM) and to a mixture of Ang II + U46619 (fixed molar ratio of 1 : 9) were obtained in single‐pass perfused kidneys isolated from 8 week‐old LH and low blood pressure (LL) control rats. Baseline vascular resistance was significantly increased in LH compared to LL kidneys. Comparison of the CRCs obtained for Ang II and U46619 showed that, in both strains, Ang II was about 100 times more potent than U46619. For both drugs, the pD2 or slope values did not differ among the two strains. Co‐activation of TP receptors, analyzed with the method of Pöch and Holzmann, tended to potentiate the effects of Ang II in LH but not in LL kidneys.In conclusion, isolated perfused kidneys of LH rat did not exhibit an increased vascular sensitivity to acute infusion of Ang II or U46619 compared to control LL ones. In addition, the results suggest that the interactions between Ang II and TP receptor agonist may differ among the two strains.
Study of in vitro glucuronidation of hydroxyquinolines with bovine liver microsomes
Authors: Kanou Masanobu , Saeki Ken‐ichi , Kato Taka‐aki , Takahashi Kazuhiko , Mizutani Takaharu 
Published: March 2003

AbstractGlucuronidation of drugs by UDP‐glucuronosyltransferase (UGT) is a major phase II conjugation reaction. Defects in UGT are associated with Crigler–Najjar syndrome and Gilbert's syndrome with severe hyperbilirubinaemias and jaundice. We analysed the reactivities of some hydroxyquinoline derivatives, which are naturally produced from quinoline by cytochrome P450. The analyses were carried out using a microassay system for UGT activity in bovine liver microsomes in the range 0.5–100 pmol/assay with the highly sensitive radio‐image analyser Fuji BAS2500 (Fujifilm, Tokyo, Japan). 3‐Hydroxylquinoline is a good substrate for glucuronidation, and the relative Kcat values were 3.1‐fold higher than the values for p‐nitrophenol. 5,6‐Dihydroquinoline‐5,6‐trans‐diol gave a similar Km value to that of 3‐hydroxyquinoline, but the Vmax value was approximately 1/15 of that of p‐nitrophenol and showed weak reactivity. Quinoline N‐oxide gave a low Vmax value and showed marginal activity. The Kcat values of 6‐hydroxyquinoline and 5‐hydroxyquinoline were 2.1‐ and 1.2‐fold higher than that of p‐nitrophenol, respectively. Fluoroquinoline (FQ) derivatives, such as 3FQ, 7,8diFQ and 6,7,8triFQ, did not show any substrate activities. These results suggest that there are therapeutic problems in administration of some quinoline drugs to patients with jaundice.
Influence of the nature of pre‐contraction on the responses to commonly employed vasodilator agents in rat‐isolated aortic rings
Authors: Streefkerk Jörn O. , de Groot Annemieke A. , Pfaffendorf Martin , van Zwieten Pieter A. 
Published: March 2003

AbstractThe relaxing properties of vasodilator drugs in vitro may depend on the characteristics of the contractile state of the vessel investigated.Rat‐isolated thoracic aortas were exposed to different types of pre‐contraction. The following vasoconstrictor agents were used: phenylephrine (PhE), a selective α1‐adrenoceptor agonist; St 587, a partial α1‐adrenoceptor stimulant; U46619 (U‐46), a thromboxane A2 agonist; and potassium ions causing receptor‐independent depolarization of the membrane. After pre‐contraction, various differential vasodilator drugs were investigated: methacholine (MCh, endothelium dependent), sodium nitroprusside (SNP, NO donor), forskolin (FSK, adenylyl cyclase stimulant) and nifedipine, a Ca2+‐antagonist (selective l‐type calcium antagonist). The vasodilator activity of these compounds was quantified by their vasodilator potency value (pD2) and efficacy (Emax) obtained from their concentration–response curves.PhE (0.1, 0.3, 3 μm) caused isometric responses of 4.8 ± 0.3, 6.5 ± 0.3 and 7.8 ± 0.5 mN, respectively. An increase of the PhE concentration from 0.1 to 3 μm did not influence the response to FSK while it reduced the pD2 of SNP (8.6 ± 0.1 to 7.35 ± 0.1). Under these conditions, only the Emax of MCh was reduced (96.3 ± 4.3% to 43.3 ± 6.9%). U46 (0.18, 0.3, 1 μm) increased the contractile force by 7.4 ± 0.4, 8.8 ± 0.3 and 10.4 ± 0.3 mN, respectively. Increasing the concentration of U‐46 from 0.18 to 1 μm affected only the efficacy of SNP (84 ± 4.4% to 17 ± 8.8%) and MCh (64.5 ± 12.3% to 0.0 ± 9.2%) and reduced the potency of FSK (7.91 ± 0.26 to 7.15 ± 0.10). The concentration of K+‐ions from 25 to 30 and 40 mm increased the contractile force by 4.0 ± 0.4, 7.0 ± 0.5 and 10.8 ± 0.4 mN, respectively. The increase in [K+ ] caused a potency decrease of FSK (7.1 ± 0.0 to 5.8 ± 0.0) whereas both efficacy and potency were reduced for SNP (95.6 ± 1.8% to 65.8 ± 1.9% and 8.7 ± 0.1 to 7.2 ± 0.1) and MCh (55.4 ± 3.5% to 24.5 ± 0.8% and 7.4 ± 0.3 to 6.1 ± 0.4). Inhibiting of the endothelial NO production by l‐NAME 100 μm resulted after pre‐contraction with PhE and potassium in comparable differences in properties for SNP. Pre‐contraction with St 587 1, 3, 10 and 30 μm shows comparable results after nifedepine relaxation.The present experiments clearly demonstrate that the characteristics of the applied pre‐contraction strongly, but differentially influence both the potency and efficacy of various vasodilator drugs in vitro. Accordingly, in vitro characterization of vasodilator drugs should be performed under a carefully standardized protocol of pre‐contraction.
Blood distribution of levocetirizine, a new non‐sedating histamine H1‐receptor antagonist, in humans
Authors: Bree Françoise , Thiault Laetitia , Gautiers Gwenaelle , Benedetti Margherita Strolin , Baltes Eugène , Rihoux Jean‐Pierre , Tillement Jean‐Paul 
Published: March 2003

AbstractThe aim of the present study was to determine (1) the extent of levocetirizine binding to human blood cells, plasma and individual plasma proteins; (2) the parameters for levocetirizine binding to individual plasma proteins both at their physiological concentrations and, for human serum albumin (HSA), at a lower saturating concentration; and (3) to simulate levocetirizine distribution in human blood using the information obtained at physiological haematocrit (H) for blood cells and at physiological concentrations for individual plasma proteins. The nature of the main binding sites of HSA, i.e. site I (warfarin) and site II (diazepam), preferentially involved in levocetirizine binding was also investigated.Over the range of therapeutic concentrations and multiples thereof, levocetirizine is extensively bound to blood components, the free fraction remaining constant (6.45%) and the fraction bound to blood cells and to plasma proteins accounting for 27.43 and 66.11%, respectively. The binding of levocetirizine to HSA in the presence of physiological concentrations of non‐esterified fatty acids (NEFAs) is the main interaction of levocetirizine in blood (50.68% of overall blood binding). This interaction is fatty acid sensitive, with decreasing concentrations of NEFA increasing the amount of bound drug and vice versa. Levocetirizine is also bound to α1‐acid‐glycoprotein and high‐density lipoproteins (5.17 and 6.89% of overall blood binding, respectively). The displacement of levocetirizine by diazepam is consistent with the binding of this drug to HSA at site II, as diazepam is a specific marker for this site. The binding of levocetirizine to HSA at site II being characterized by a low association constant, other drugs sharing the same site with high association constants cannot displace levocetirizine except at very high plasma concentrations. In any case, at therapeutic concentrations of levocetirizine and at physiological protein concentrations, the observation that none of the levocetirizine binding proteins is saturated suggests that very little or no variation of the free fraction will occur although a different distribution of its bound forms is possible.
Metabolism of tresperimus by rat aorta semicarbazide‐sensitive amine oxidase (SSAO)
Authors: Claud P. , Artur Y. , Guichard J.‐P. , Laine R. 
Published: March 2003

AbstractTresperimus (Cellimis®), a new immunosuppressive agent, is mainly eliminated in the rat through metabolism, in which the oxidative deamination of the primary amine of the drug plays a major role. We have previously demonstrated in vivo the significant involvement of semicarbazide‐sensitive amine oxidase (SSAO) in this reaction. Rat aorta, a tissue with one of the highest specific SSAO activities, was tested as a new in vitro model to elucidate tresperimus metabolism, using a combination of liquid chromatography/mass spectrometry (LC/MS) and high‐performance liquid chromatography (HPLC) analyses. The metabolites resulting from the main metabolic pathway of the drug were formed in rat aorta homogenates. The use of various SSAO, lysyl oxidase and monoamine oxidase inhibitors confirmed that SSAO is predominantly involved in the main site of tresperimus metabolism but also in every metabolic pathway of the drug, including deamination of tresperimus metabolites M3 (desaminopropyl derivative of tresperimus) and M6 (guanidinohexylamine). A microsomal fraction of the rat aorta was used to characterize tresperimus deamination. The moderate affinity of membrane‐bound SSAO for tresperimus, with a Km value of 66 µm, was counterbalanced by a catalytic efficiency superior to that of certain physiological substrates of SSAO, such as methylamine. The rat aorta provided an interesting model with which to study tresperimus metabolism, highlighting the important role that SSAO could play as a phase I oxidative enzyme in the metabolism of certain exogenous amines at the vascular level.
Cardiovascular autonomic nervous system tests: reference values in young people (15–19 years) and influence of age and gender
Authors: Tonhajzerová Ingrid , Javorka Kamil , Javorka Michal , Petrášková Mária 
Published: March 2003

SummaryObjective:  The aim of this study was to determine values of the deep breathing test (DB), orthostatic test (OT) and Valsalva manoeuvre (VM) parameters in young people and influence of age and gender.Methods:  A total of 206 healthy subjects (100 girls, 106 boys) at the age of 15–19 years, BMI 21·3±2·3 (mean ± SD) were examined by system Varia Pulse TF3.Results:  Reference values of DB, OT, VM parameters are presented as arithmetic mean ± SD and percentiles (P90, P75, P50, P25, P10). In the whole group HRrest was lower in 19‐year‐old group, in OT this difference was significant already in 18‐year‐old group compared with 15‐year‐old group. DB: I/E was significantly increased in 19‐year‐old group compared with 15‐year‐old group. HRrest was higher in girls compared with boys in the whole group. DB: I/E was significantly lower in girls compared with boys. OT: 30:15 and HRmax/HRrest were significantly decreased in girls compared with boys.Conclusion:  Reference values of DB, OT, VM parameters were determined in young people at the age of 15–19 years. The most sensitive test for ascertainment of developmental changes was test of deep breathing. I/E was increased in the 19‐year‐old group compared with 15‐year‐old group indicating an increase of vagal activity. Girls had decreased some parameters of deep breathing and orthostatic test compared with boys in the same group (15–19 years).