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  • 2000-2004  (43)
  • 2004  (43)
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  • 2000-2004  (43)
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  • 1
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: This study examined factors affecting germination, survival, and growth of the grass trees Xanthorrhoea gracilis and X. preissii on newly rehabilitated bauxite mine pits in the jarrah forest of southwestern Australia. Grazing by kangaroos (Macropus fuliginosus) was the major factor in reducing survival and growth of both species during the first 2 years. Provision of artificial grazing protection increased survival and growth (plant mass) of both species by 3-fold. Grazing by native vertebrates has not previously been identified as affecting mine restoration in Western Australia. Initial germination rates from sown seeds of X. preissii at eight replicate sites ranged from 25 to 64% with a mean of 42%. Corresponding figures for X. gracilis were 5–42% with a mean of 17%. Germination of X. gracilis was greater on heavier, moister soils, but X. preissii germinated better on sandier soils. High levels of initial germination did not ensure high survival. Plants of both species grew bigger and survived better on the lighter, sandy soils. Xanthorrhoea seedlings located in the depressions created by the ripping process grew larger than seedlings on the slopes of the riplines. The presence of plants of other species did not have a significant effect on survival. However, these plants facilitated the growth of both species when artificial grazing protection was unavailable. Plants of other species reduced the growth rates of Xanthorrhoea seedlings where artificial grazing protection was provided. Artificial shade by itself had no significant effect on growth of either species. In rehabilitated bauxite mines in the jarrah forest, the provision of grazing protection is recommended to ensure successful establishment and early survival of Xanthorrhoea spp.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Soil use and management 20 (2004), S. 0 
    ISSN: 1475-2743
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract. Drainage water was sampled intensively during a four-year field experiment on a sandy loam soil subjected to four unreplicated tillage treatments: (1) harrowing with a springtine harrow, drilling; (2) direct drilling; (3) ploughing with light subsurface compaction, one pass with a PTO-driven rotary harrow, drilling; (4) ploughing, one pass with a springtine harrow, drilling. In all years, the losses of suspended matter with drainage water (0.1–4.3 kg ha−1 yr−1) were smaller by a factor of 1.9 or more from direct drilled plots than from plots subjected to the other tillage treatments, strongly suggesting that tillage increased the losses. Annual bromide losses were governed by the amount of drainage water rather than by the tillage treatments. However, after one drainage season, more bromide was left in the soil at 0–100 cm depth with ploughless tillage than with ploughing, thus indicating more bypass flow without ploughing. The study demonstrated very changeable patterns of suspended matter and bromide concentrations in drainage water sampled from large field plots, and questions the representativeness of drainage water samples for water reaching the subsoil or shallow groundwater.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Receptor phosphorylation, arrestin binding, uncoupling from G protein and subsequent endocytosis have been implicated in G protein-coupled receptor desensitization after chronic agonist exposure. In search of proteins regulating the µ-opioid receptor endocytosis, we have recently established that activation of phospholipase D (PLD)2 is required for agonist-induced µ-opioid receptor endocytosis. In this study, we determined the effect of PLD2 activity on the desensitization and resensitization rate of the µ-opioid receptor. We clearly demonstrated that inhibition of PLD2-mediated phosphatidic acid formation by alcohol (1-butanol or ethanol) or overexpression of a dominant negative mutant of PLD2 prevented agonist-mediated endocytosis and resulted in a faster desensitization rate of the µ-opioid receptor after chronic (d-Ala2, Me Phe4, Glyol5)enkephalin treatment in human embryonic kidney 293 cells. Moreover, inhibition of PLD2 activity led to an impairment of the resensitization rate of the µ-opioid receptor. In summary, our data strongly suggest that PLD2 is a modulator of agonist-induced endocytosis, desensitization and resensitization of the µ-opioid receptor.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The most prevalent single-nucleotide polymorphism (SNP) A118G in the human µ-opioid receptor gene predicts an amino acid change from an asparagine residue to an aspartatic residue in amino acid position 40. This N40D mutation, which has been implicated in the development of opioid addiction, was previously reported to result in an increased β-endorphin binding affinity and a decreased potency of morphine-6-glucuronide. Therefore, in the present study we have investigated whether this mutation might affect the binding affinity, potency, and/or the agonist-induced desensitization, internalization and resensitization of the human µ-opioid receptor stably expressed in human embryonic kidney 293 cells. With the exception of a reduced expression level of N40D compared to human µ-opioid receptor (hMOR) in HEK293 cells, our analyses revealed no marked functional differences between N40D and wild-type receptor. Morphine, morphine-6-glucuronide and β-endorphin revealed similar binding affinities and potencies for both receptors. Both the N40D-variant receptor and hMOR exhibited robust receptor internalization in the presence of the opioid peptide [d-Ala2,N-MePhe4,Glyol5]enkephalin (DAMGO) and β-endorphin but not in response to morphine or morphine-6-glucuronide. After prolonged treatment with morphine, morphine-6-glucuronide or β-endorphin both receptors showed similiar desensitization time courses. In addition, the receptor resensitization rates were nearly identical for both receptor types.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Based on the information of the interdisciplinary task force on allergy diagnostics in the metal branch, in 2001, the German Contact Dermatitis Research Group (DKG) compiled two metalworking fluid (MWF) test series with currently and previously used components, respectively. After 2 years of patch testing, we present results obtained with these series, based on data of the Information Network of Departments of Dermatology (IVDK). 251 metalworkers who were patch tested because of suspected MWF dermatitis in 2002 and 2003 were included in this retrospective data analysis. Of these, 206 were tested with the current MWF series and 155 with the historical MWF series. Among the current MWF allergens, monoethanolamine ranked 1st with 11.6% positive reactions. Diethanolamine (3.0%), triethanolamine (1.1%), and diglycolamine (1.9%) elicited positive reactions far less frequently. Allergic reactions to p-aminoazobenzene were frequently observed (6.0%), but the relevance of these reactions is still obscure. Positive reactions to biocides ranged from 4.5% for Bioban® CS 1135 to 0.5% for iodopropynyl butylcarbamate and 2-phenoxyethanol. Concomitant reactions to formaldehyde, which caused positive reactions in 3.3%, and formaldehyde releasers occurred to varying extents without conclusive pattern. No positive reactions were seen to dibutyl phthalate, di-2-ethylhexyl phthalate, tricresyl phosphate, isopropyl myristate or benzotriazole. With the historical MWF test series, positive reactions to methyldibromo glutaronitrile (MDBGN) were observed most frequently. However, sensitization via allergen sources other than MWF seems likely, as MDBGN, during the study period, has been one of the most frequent preservative allergens in cosmetics and body care products. Other historical MWF allergens comprised morpholinyl mercaptobenzothiazole (3.3%), benzisothiazolinone (BIT; 2.0%) and Bioban® P 1487(1.3%). BIT is currently used in MWF again, so it was shifted to the current MWF test series. As decreasing reaction frequencies to former MWF allergens that are no longer used can be expected, the historical series should be re-evaluated after some years. The test series with current MWF allergens has to be kept up-to-date based on information from industry and to be kept concise by eliminating test substances which never cause positive reactions.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 66 (2004), S. 49-75 
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Notes: In recent years there has been a rapid expansion in our understanding of the molecular biology that underpins human physiology. In the heart, elegant molecular pathways have been elucidated, and derangements in these pathways have been identified as factors in cardiac disease. However, as our understanding has grown, we have recognized that there exist only relatively crude tools to effect changes in molecular pathophysiology. The ultimate promise of gene therapy is to correct the molecular derangements that cause illness. To bring this promise to fruition in the clinical arena, many problems need to be solved, and chief among these remains reliable and robust delivery of genes to the target organ. To this end, viral vectors have been utilized with success more frequently than any other method of gene delivery. The use of these vectors in the heart has already offered promising novel benefit for human ischemic heart disease, and studies in animal models have given glimpses of hope that gene therapy may provide future therapeutic benefit in heart failure by improving cardiac function.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Mannose-binding lectin (MBL) is an important component of innate immunity that can bind to certain sugar residues on the surface of many types of pathogenic micro-organisms. On binding, MBL generates opsonic activity mainly through activation of the complement system. Genetically determined MBL deficiency is very common and can be associated with increased susceptibility to a variety of infections, especially in children and immunosuppressed individuals. The potential benefits of MBL reconstitution therapy therefore need to be evaluated. We have carried out a phase I safety and pharmacokinetic study on 20 MBL-deficient healthy adult volunteers. The MBL was prepared from plasma of nonremunerated, voluntary Danish donors tested and found negative for hepatitis B surface antigen, antibodies to human immunodeficiency virus (HIV) and hepatitis C virus. Each volunteer received a total of 18 mg of MBL in three 6 mg doses given intravenously, once weekly over a period of 3 weeks. The volunteers were closely monitored at the University Hospital in Reykjavik for 8 h after each infusion and daily thereafter for 5 days after each infusion. No adverse clinical or laboratory changes were observed in any of the 20 participants, and frequent measurements did not reveal any signs of infusion-associated complement activation. No antibodies to MBL, HIV or hepatitis viruses were observed 24 weeks after the last infusion. Serum MBL levels increased up to normal levels (1200–4500 ng/ml) immediately after each infusion, but the half-life of the infused MBL was highly variable, ranging from 18 to 115 h (mean 69.6). It is concluded that infusion of purified MBL as prepared by Statens Serum Institut (SSI) is safe. However, adults have to be given at least 6 mg twice or thrice weekly for maintaining protective MBL levels assumed to be about 1000 ng/ml.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 19 (2004), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Neurodevelopmental models of schizophrenia posit that early brain damage leads to dys- or misconnection effects possibly altering synaptic transmission in brain sites distal of the lesion. We tested the hypothesis that neonatal medial prefrontal cortex (mPFC) lesions affect the sensitivity of the mesoaccumbal dopamine (DA) system. Using extracellular single-unit recordings combined with systemic application of the DA agonist apomorphine, followed by the D2 receptor antagonist haloperidol or the D1 receptor antagonist SCH23390, we compared electrophysiological properties of nucleus accumbens core and shell neurons after bilateral excitotoxic lesions of mPFC induced at postnatal day 7 or in adult rats. Whereas animals with adult mPFC lesions showed an altered discharge pattern within the core region, neonatal mPFC lesions altered the discharge pattern within the shell region. Subcutaneous administration of apomorphine (4 mg/kg) reduced accumbal firing rate in 77% of all neurons. Onset and magnitude of apomorphine-induced inhibition of neuronal activity was faster and stronger in rats with neonatal but not adult mPFC lesions in both core and shell regions. Apomorphine-induced inhibition was partially reversed by 0.1 mg/kg haloperidol only in core region of neonatal lesioned rats. Apomorphine-induced excitation of neuronal activity (in 21% of all neurons) was reversed by the D1 receptor antagonist SCH23390 (0.1 mg/kg) in all excited neurons. These data support the hypothesis that neonatal but not adult lesions of mPFC alter cortico-striatal networks and suggest that disturbance of mPFC development leads to neurodevelopmental changes in mesoaccumbal DA system during adulthood.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 20 (2004), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Auditory brainstem neurons that are involved in the precise analysis of the temporal pattern of sounds have ionic currents activated near the resting potential to shorten membrane time constants. One of these currents is the hyperpolarization-activated current (Ih). Molecular cloning of the channels underlying Ih revealed four different isoforms (HCN1–4). HCN1 and HCN2, which are widely distributed in the brain, differ in their activation kinetics, voltage dependence and sensitivity to cAMP. We determined the distribution of the HCN1 and HCN2 isoform in the auditory brainstem and midbrain of young rats (P20–30), using standard immunohistochemical techniques. HCN1 antibodies gave rise to punctate staining on the somatic and dendritic membrane. Strong HCN1 staining was present on octopus and bushy cells of the ventral cochlear nucleus, principal neurons of the lateral and medial superior olive, and neurons of the ventral nucleus of the lateral lemniscus. No HCN1 staining was observed in the dorsal cochlear nucleus and the medial nucleus of the trapezoid body (MNTB). In contrast, HCN2 staining was strongest in the MNTB and the dorsal nucleus of the lateral lemniscus. Strong HCN2 antibody labelling was also observed in bushy cells of the ventral cochlear nucleus. In the central nucleus of the inferior colliculus only a subpopulation of neurons showed HCN1 or HCN2 immunolabelling. This differential distribution of HCN1 and HCN2 channels is in agreement with the physiologically observed Ih currents in corresponding neuronal populations and might represent the basis for functional heterogeneity and diverse sensitivity to neuromodulators.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: The magnitude of changes in carboxylation capacity in dominant plant species under long-term elevated CO2 exposure (elevated pCa) directly impacts ecosystem CO2 assimilation from the atmosphere. We analyzed field CO2 response curves of 16 C3 species of different plant growth forms in favorable growth conditions in four free-air CO2 enrichment (FACE) experiments in a pine and deciduous forest, a grassland and a desert. Among species and across herb, tree and shrub growth forms there were significant enhancements in CO2 assimilation (A) by +40±5% in elevated pCa (49.5–57.1 Pa), although there were also significant reductions in photosynthetic capacity in elevated pCa in some species. Photosynthesis at a common pCa (Aa) was significantly reduced in five species growing under elevated pCa, while leaf carboxylation capacity (Vcmax) was significantly reduced by elevated pCa in seven species (change of −19±3% among these species) across different growth forms and FACE sites. Adjustments in Vcmax with elevated pCa were associated with changes in leaf N among species, and occurred in species with the highest leaf N. Elevated pCa treatment did not affect the mass-based relationships between A or Vcmax and N, which differed among herbs, trees and shrubs. Thus, effects of elevated pCa on leaf C assimilation and carboxylation capacity occurred largely through changes in leaf N, rather than through elevated pCa effects on the relationships themselves. Maintenance of leaf carboxylation capacity among species in elevated pCa at these sites depends on maintenance of canopy N stocks, with leaf N depletion associated with photosynthetic capacity adjustments. Since CO2 responses can only be measured experimentally on a small number of species, understanding elevated CO2 effects on canopy Nm and Na will greatly contribute to an ability to model responses of leaf photosynthesis to atmospheric CO2 in different species and plant growth forms.
    Type of Medium: Electronic Resource
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