Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 733 (1994), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 21 (2005), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this work is to identify human neural circuits involved in inhibition of accommodation/vergence by contrasting the cortical functions subservient to negative voluntary accommodation/vergence (NVA) with those evoked by active fixation in darkness (FIX). Five subjects with normal corrected acuity were studied using positron emission tomography and the H〈inlineGraphic alt="inline image" href="urn:x-wiley:0953816X:EJN4140:EJN_4140_mu1" location="equation/EJN_4140_mu1.gif"/〉O bolus technique. The dominant right eye viewed a laser speckle pattern (633 nm) whose direction and velocity of motion were determined by the refractive state of the eye. The speckle pattern was presented at a distance of 1.8 m (0.55 D). The non-dominant eye was patched. Subjects performed two tasks counterbalanced for order effects: (i) attempted fixation on the remembered target in darkness with the dominant eye open and ‘fixating’; and (ii) voluntary reduction of the laser speckle flow during each alternate 20-s epoch when a convex +2.0 D lens was placed in front of the right eye causing the speckle pattern to move downwards at 3 °/s. Comparison of the condition of NVA with the condition of FIX indicated widespread occipital activation. Decreases in absolute regional cerebral blood flow occurred in the superior parietal cortex (BA 5), frontal cortex (BA 8 and 10) and within the postcentral/precentral gyrus (BA 1/2/3/4) bilaterally where deactivation clusters eclipsed the presumed neck and shoulder areas. Negative accommodation/vergence appears to be driven by a reduction of parasympathetic tone, and has the effect of shutting down brain regions known to be involved in regulating visual search as well as a centrally controlled eye–head–neck–shoulder motor programme responsible for posturing gaze.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 22 (2005), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The pine shoot beetles Tomicus minor and T. piniperda are common in the Nordic countries. Of these, T. piniperda may attack and kill living but severely stressed trees, whereas T. minor has never been reported to be individually responsible for killing live trees. Both species are associated with blue-stain fungi: T. minor with Ophiostoma canum and T. piniperda with Leptographium wingfieldii and Ophiostoma minus. The growth of these fungi was studied in phloem and sapwood of live Scots pine trees, on malt agar, and on malt agar under oxygen-deficient conditions. Leptographium wingfieldii was more virulent (i.e. caused more extensive host symptoms) grew more quickly on malt agar, and was less affected by oxygen-deficient growth conditions than either O. minus or O. canum. Ophiostoma canum was least virulent. In low-density inoculations it induced lesions similar to those induced by sterile control inoculations; it grew very slowly on malt agar and stopped growing after ≈30 mm under oxygen-deficient conditions. Ophiostoma minus was intermediate in all respects. The different virulence of the blue-stain fungi associated with the two pine shoot beetles may explain the lower level of aggressiveness in T. minor.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1435-1463
    Keywords: Tomography ; monkey ; L-DOPA ; aromatic L-amino acid decarboxylase ; catechol-O-methyltransferase ; Parkinson's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Positron emission tomography (PET) following intravenous administration of β-[11 C]-L-DOPA provides a method of assessing regional cerebral uptake and utilization of levodopa. Cerebral levodopa kinetics in the rhesus monkey were investigated after the inhibition of catechol-O-methyltransferase (COMT) with RO 40-7592, and after coadministration of the peripheral aromatic L-amino acid decarboxylase (AADC) inhibitors benserazide and carbidopa. Pretreatment with RO 40-7592 (10 mg/kg), benserazide (10 mg/kg) or carbidopa (3.5 mg/kg) did not change striatal k3, which mainly reflects the ability for the brain tissue to convert [11C]-L-DOPA to [11C]-dopamine, although the brain's uptake of radioactivity increased substantially after pretreatment with the AADC inhibitors. When benserazide was coadministered with RO 40-7592 (10 mg/kg) a dose-dependent decrease in striatal k3 was measured with an apparent ED50 of 3 mg/kg. No such effect was indicated after pretreatment with the combination of RO 40-7592 (10 mg/kg) and carbidopa (3.5 mg/kg). The possible negative interactions of coadministration with COMT inhibitors and predominantly peripherally acting AADC inhibitors must be considered when used in the therapy of Parkinson's disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1435-1463
    Keywords: Positron emission tomography ; PET ; Alzheimer's disease ; (+) (R) N-11C-methyl nicotine ; (−) (S) N-11C-methyl nicotine ; brain ; nicotinic receptors ; cholinergic receptors ; diagnostic marker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Positron emission tomography of the brain following intravenous injection of (+) (R) and (−) (S) N-[11C-methyl]nicotine showed a marked reduced uptake of both isomers, especially the (R) form, in Alzheimer patients as compared to age-matched controls. The significantly larger difference between the uptake values of the (S)- and (R)-enantiomers of11C-nicotine in Azheimer brains may be of diagnostic value.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1435-1463
    Keywords: Positron emission tomography ; PET ; focal dystonia ; torticollis ; [11C]-N-methyl-spiperone ; dopamine receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Specific binding of [11C]-N-methyl-spiperone to striatal dopamine D2 receptors was assessed using positron emission tomography (PET) in 6 patients with adult-onset focal dystonia (predominantly spasmodic torticollis) and in 5 healthy subjects. No significant difference in average specific striatal tracer uptake between patients and healthy subjects was found. However, in the 5 patients showing lateralisation of clinical signs a trend to higher striatal tracer uptake in the contralateral hemisphere was observed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1435-1463
    Keywords: 5-Hydroxy-(β-11 C)-L-tryptophan ; monkey ; positron emission tomography ; enzyme inhibition ; decarboxylation rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 5-Hydroxy-L-tryptophan labelled with 11 C is introduced as a tracer for the in vivo assessment of brain serotonin synthesis in the Rhesus monkey using positron emission tomography, PET. Increasing radioactivities were seen in the striatal area in contrast to that seen in other brain regions. Following 11 C-labelled L-tryptophan an even spread of brain radioactivity was seen. This selective increase most probably results from the decarboxylation of tracer and retention of formed products since no striatal increase of radioactivity was seen when 5-hydroxy-L-tryptophan labelled with 11 C in the carboxy-position was administered. Furthermore, pretreatment of the monkey with a centrally active decarboxylase inhibitor (NSD 1015,10 mg/kg) did not lead to increased striatal radioactivities after the administration of 5-hydroxy-(β-11C)-L-tryptophan. The selective utilization of the radiotracer in the striatal area increased with a rate constant calculated to be 0.0055 ± 0.0015 min−1 (n = 5) using the surrounding brain as reference area. A non-significant influence of radiolabelled metabolites to the rate constants measured was shown after pretreatment of the monkeys with selective and non-selective monoamine oxidase inhibitors, respectively. These results may give a basis for the use of the new tracer 5-hydroxy-(β-11 C)-L-tryptophan in PET-studies of brain serotonin metabolism in health and disease.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1435-1463
    Keywords: L-[11C]DOPA ; brain radioactivity ; decarboxylation rate ; pharmacological perturbations ; healthy volunteers ; positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The in vivo dopamine precursor L-3,4-dihydroxyphenylalanine (L-DOPA) labelled with11 C in the Β position has been used for positron emission tomography studies of L-DOPA utilization in the brain. The brain uptake and kinetics of L-[11 C]DOPA-derived radioactivity were studied in healthy male volunteers, and the specific utilization, i.e. decarboxylation rate of L-[11 C]DOPA in different brain areas, was quantified using a brain region devoid of specific L-[11C]DOPA utilization as reference. Total uptake of L-[11 C]DOPA-derived radioactivity measured in the brain varied two- to threefold between subjects, with highest radioactivity in the striatal region. Specific utilization of L-[11C]DOPA radioactivity in the striatal region and in the prefrontal cortex varied twofold between subjects. No specific utilization was observed in other regions of the brain. The uptake of radioactivity in the brain increased dose-dependently with the simultaneous administration of unlabelled L-DOPA up to 10 mg. On the other hand, a decrease in brain radioactivity uptake was measured after pretreatment with 1 mg/kg oral L-DOPA, indicating competition for transport across the blood-brain barrier. Benserazide 0.5 mg/ kg orally increased somewhat the radioactivity uptake to the brain. None of these pharmacological perturbations demonstrated any clearcut effect on specific utilization of L-[11C]DOPA. Thus,11C-labelled L-DOPA is introduced as an alternative to the well-established L-6-[18 F]fluoro-DOPA methodology in clinical studies on brain L-DOPA uptake and dopamine synthesis.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...