26 results on '"Cornelissen K"'
Search Results
2. Handelman's hierarchy for the maximum stable set problem
- Author
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Laurent, M., Sun, Z., Cornelissen, K., Hoeksma, R., Hurink, J., Manthey, B., Research Group: Operations Research, and Econometrics and Operations Research
- Published
- 2013
3. Relaxation of 3-partition instances
- Author
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Joosten, S.J.C., Zantema, H., Cornelissen, K., Hoeksma, R., Hurink, J., Manthey, B., Design and Analysis of Systems, and Formal System Analysis
- Abstract
The 3-partition problem admits a straightforward formulation as a 0-1 Integer Linear Program (ILP). We investigate problem instances for which the half-integer relaxation of the ILP is feasible, while the ILP is not. We prove that this only occurs on a set of at least 18 elements, and in case of 18 elements such an instance always contains an element of weight = 10. These bounds are sharp: we give all 14 instances consisting of 18 elements all having weight = 10. Our approach is based on analyzing an underlying graph structure.
- Published
- 2013
4. Observation and evolution of finite-dimensional Markov systems
- Author
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Faigle, U., Schönhuth, Alexander, Cornelissen, K., Hoeksma, R., Hurink, Johann, Manthey, B., and Evolutionary Intelligence
- Published
- 2013
5. Concept mapping of indicators for treatment allocation in patients with personality disorders
- Author
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van Manen, J.G., Goossensen, A., Knapen, P., Ingenhoven, T., de Saeger, H., Cornelissen, K., Kamphuis, J.H., Timman, R., Verheul, R., Busschbach, J.J.V., and Klinische Psychologie (Psychologie, FMG)
- Abstract
In dit onderzoek werden met behulp van de ‘concept-mapping’-methode patiëntkenmerken gevonden die van belang zijn bij de indicatiestelling voor psychotherapeutische behandeling bij persoonlijkheidsstoornissen. De concept map-methode omvat zowel kenmerken van kwalitatief als kwantitatief onderzoek en heeft als doel om een complex onderwerp visueel te presenteren en op te delen in een aantal onderliggende concepten. In dit onderzoek werd met behulp van de concept map-methode een literatuuronderzoek naar indicatiestelling geïntegreerd met kennis van 29 experts op het gebied van indicatiestelling en/of persoonlijkheidsproblematiek. Het doel was om een beperkt aantal concepten te bepalen die van belang zijn voor de indicatiestelling bij persoonlijkheidsproblemen. De conceptmap resulteerde in acht clusters: (1) ernst van de psychiatrische symptomatologie, (2) ernst van de (structurele) persoonlijkheidspathologie, (3) ego-adaptieve vermogens, (4) motivatie en vermogen tot het aangaan van een werkrelatie, (5) sociale context, (6) socio-demografische variabelen, (7) traumatisering en (8) behandelgeschiedenis en somatiek. In dit rapport wordt gedetailleerd verslag gedaan van de concept-map procedure en worden de uitkomsten gedetailleerd besproken.
- Published
- 2010
6. Rassenonderzoek trostomaat : onderzoek België en Nederland gebundeld
- Author
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Steenbergen, P. and Cornelissen, K.
- Subjects
crop quality ,characteristics ,variety trials ,netherlands ,gewaskwaliteit ,belgium ,karakteristieken ,landbouwkundig onderzoek ,agricultural research ,nederland ,performance testing ,biologische landbouw ,organic farming ,quality ,glasgroenten ,glastuinbouw ,rassenproeven ,tomaten ,kwaliteit ,tomatoes ,greenhouse vegetables ,prestatie-onderzoek ,belgië ,greenhouse horticulture - Abstract
Gedurende het teeltseizoen 2002/2003 wordt door het Belgische Proefcentrum te Kruishoutem en het PPO Glastuinbouw in Naaldwijk samengewerkt aan rassenonderzoek met biologisch geteelde trostomaten. Uitleg over de opzet van de proeven, de beoordelingscriteria (vruchtkenmerken; gewaskenmerken; houdbaarheid, smaak), en de eerste resultaten
- Published
- 2003
7. Rassen trostomaat vergeleken : grote verschillen tussen de diverse rassen
- Author
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Cornelissen, K., Hogendonk, L., and Steenbergen, P.
- Subjects
agronomic characteristics ,disease resistance ,characteristics ,yields ,variety trials ,opbrengsten ,rassen (planten) ,karakteristieken ,resistance ,weerstand ,use value ,ziekteresistentie ,organic farming ,rassenproeven ,cultivars ,gewasopbrengst ,kwaliteit ,tomatoes ,greenhouse vegetables ,greenhouse horticulture ,crop quality ,gewaskwaliteit ,crop yield ,performance testing ,biologische landbouw ,quality ,solanum lycopersicum ,varieties ,gebruikswaarde ,glasgroenten ,glastuinbouw ,agronomische kenmerken ,tomaten ,prestatie-onderzoek - Abstract
Het Provinciaal Proefcentrum voor de Groenteteelt te Kruishouten (België) en PPO Glastuinbouw (Naaldwijk) onderzochten een groot aantallen trostomatenrassen op hun geschiktheid voor de biologische teelt. In tabellen de beoordelingscijfers voor vruchtkwaliteit, resistentie tegen diverse plagen en ziekten, en productie. Verder uitgebreide omschrijvingen per ras. Bij rassen waarvan nog geen biologisch zaad voorhanden is hebben de deelnemende veredelingsbedrijven de intentie uitgesproken dit te produceren indien noodzakelijk
- Published
- 2003
8. Observation and evolution of finite-dimensional Markov systems
- Author
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Cornelissen, K., Hoeksma, R., Hurink, J., Manthey, B., Faigle, U., Schönhuth, A. (Alexander), Cornelissen, K., Hoeksma, R., Hurink, J., Manthey, B., Faigle, U., and Schönhuth, A. (Alexander)
- Published
- 2013
9. Absorption, metabolism, and excretion of (H)-ospemifene following a single oral dose to post-menopausal women
- Author
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BRYSON, S, primary, CORNELISSEN, K, additional, and ANTTILA, M, additional
- Published
- 2005
- Full Text
- View/download PDF
10. The Pharmacokinetics, Metabolism and Exretion of Sitafloxacin Following A Single Oral Dose to Healthy Male Subjects
- Author
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Yamaguchi, M., primary, Haque, N., additional, and Cornelissen, K., additional
- Published
- 2003
- Full Text
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11. Absorption, metabolism and excretion of tamsulosin hydrochloride in man
- Author
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Soeishi, Y., primary, Matsushima, H., additional, Watanabe, T., additional, Higuchi, S., additional, Cornelissen, K., additional, and Ward, J., additional
- Published
- 1996
- Full Text
- View/download PDF
12. Body size estimation in women with anorexia nervosa and healthy controls using 3D avatars
- Author
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Cornelissen, K. K., McCarty, K., Cornelissen, P. L., Tovee, M. J., Cornelissen, K. K., McCarty, K., Cornelissen, P. L., and Tovee, M. J.
- Abstract
A core feature of anorexia nervosa is an over-estimation of body size. However, quantifying this over-estimation has been problematic as existing methodologies introduce a series of artefacts and inaccuracies in the stimuli used for judgements of body size. To overcome these problems, we have: (i) taken 3D scans of 15 women who have symptoms of anorexia (referred to henceforth as anorexia spectrum disorders, ANSD) and 15 healthy control women, (ii) used a 3D modelling package to build avatars from the scans, (iii) manipulated the body shapes of these avatars to reflect biometrically accurate, continuous changes in body mass index (BMI), (iv) used these personalized avatars as stimuli to allow the women to estimate their body size. The results show that women who are currently receiving treatment for ANSD show an over-estimation of body size which rapidly increases as their own BMI increases. By contrast, the women acting as healthy controls can accurately estimate their body size irrespective of their own BMI. This study demonstrates the viability of combining 3D scanning and CGI techniques to create personalised realistic avatars of individual patients to directly assess their body image perception.
13. An interactive training programme to treat body image disturbance
- Author
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Gledhill, L. J., Cornelissen, K. K., Cornelissen, P. L., Penton-Voak, I. P., Munafo, M. R., Tovée, Martin J., Gledhill, L. J., Cornelissen, K. K., Cornelissen, P. L., Penton-Voak, I. P., Munafo, M. R., and Tovée, Martin J.
- Abstract
Objectives: Anorexia nervosa (AN) is a life-threatening mental health condition. A core feature is a disturbance of body image, such that sufferers see themselves as fatter than they actually are. Design: We tested the effectiveness of a novel training program to recalibrate our participants’ perception of body size. Methods: In a novel adaptation of a cognitive bias training program, participants judged the body size of a series of female bodies and were given feedback to improve their accuracy over 4 daily training sessions. In Study 1, we recruited young women with high concerns about their body size for a randomised controlled study. In Study 2, we then applied the training program to a case series of women with atypical AN. Results: In Study 1, the training program significantly improved the body size judgements of women with high body concerns compared to controls. We also found evidence of improved body image and reduced eating concerns in this group. In Study 2, the program again recalibrated the body size judgements of women with atypical AN. We also saw evidence of a clinically meaningful reduction in their body size and eating disordered concerns. Conclusions: This training has the potential to be a valuable treatment used together with more traditional talking therapies.
14. View-dependent accuracy in body mass judgements of female bodies
- Author
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cornelissen, P. L., Cornelissen, K. K., Groves, V., McCarty, K., Tovee, M., cornelissen, P. L., Cornelissen, K. K., Groves, V., McCarty, K., and Tovee, M.
- Abstract
A fundamental issue in testing body image perception is how to present the test stimuli. Previous studies have almost exclusively used images of bodies viewed in front-view, but this potentially obscures key visual cues used to judge adiposity reducing the ability to make accurate judgements. A potential solution is to use a three-quarter view, which combines visual cues to body fat that can be observed in front and profile. To test this hypothesis, 20 female observers completed a 2-alternative forced choice paradigm to determine the smallest difference in body fat detectable in female bodies in front, three-quarter, and profile view. There was a significant advantage for three-quarter and profile relative to front-view. Discrimination accuracy is predicted by the saliency of stomach depth, suggesting that this is a key visual cue used to judge body mass. In future, bodies should ideally be presented in three-quarter to accurately assess body size discrimination.
15. Study of the absorption, metabolism, and excretion of (14C)-ramelteon (TAK-375).
- Author
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Stevenson, S., Cornelissen, K., Clarke, E., and Hibberd, M.
- Published
- 2004
- Full Text
- View/download PDF
16. Absorption, metabolism and excretion of tamsulosin hydrochloride in man
- Author
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Higuchi, S., Watanabe, T., Matsushima, H., Ward, J., Soeishi, Y., and Cornelissen, K.
- Subjects
ABSORPTION ,EXCRETORY organs ,METABOLISM - Published
- 1996
17. Study of the absorption, metabolism, and excretion of (14C)-ramelteon (TAK-375)
- Author
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Stevenson, S., Cornelissen, K., Clarke, E., and Hibberd, M.
- Abstract
This study investigated the pharmacokinetics, metabolism and excretion of ramelteon, a novel selective ML1receptor agonist. Six healthy male subjects received a single oral dose of 16 mg (14C)-ramelteon. Ramelteon was rapidly absorbed (tmaxof 0.3 hours) and eliminated (half-life of 1.2 hours). The metabolites MI, MI, MI11 and MIV were rapidly formed and eliminated (half-lives of 1 to 3 hours). Systemic exposure of metabolite M-II (major active metabolite) was 20- to 30-fold greater than that of ramelteon, while the exposures of M-I, M-III, and M-IV were one- to four-fold higher than that of ramelteon. Of total radioactivity administered, 84% was renally eliminated, and 4% was faecally eliminated, with metabolites of ramelteon accounting for the majority of the dose eliminated. High urinary recovery of radioactivity indicates that there was at least 84% oral absorption of ramelteon. Negligible urinary excretion of ramelteon and low serum concentrations of ramelteon (relative to metabolites) indicate that ramelteon undergoes extensive first-pass metabolism. Ramelteon was metabolized primarily via oxidation to hydroxyl and carbonyl groups, with secondary metabolism to form glucuronide conjugates.Clinical Pharmacology & Therapeutics (2004) 75, P22–P22; doi: 10.1016/j.clpt.2003.11.084
- Published
- 2004
- Full Text
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18. Consumers' perception of cultured meat relative to other meat alternatives and meat itself: A segmentation study.
- Author
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Cornelissen K and Piqueras-Fiszman B
- Subjects
- Animals, Insecta, Perception, Consumer Behavior, Food Preferences, Meat analysis
- Abstract
Cultured meat is still under development but could possibly serve as a meat alternative. As a result, the acceptance and perception of cultured meat have received considerable attention in consumer research. However, only few comparisons to meat or meat alternatives have been made, which makes it unclear how cultured meat compares to these products. This is the first study to directly compare cultured meat to plant-based meat alternatives (PBMA), fish, insects, and conventional meat. Dutch consumers (n = 288) evaluated their perception and willingness to consume (WTC) patties made from the five sources listed above. Consumer segmentation based on the WTC ratings was performed, and the resulting clusters were compared in terms of their preferences, perception of cultured meat, and demographic and psychographic variables. To see if naming affected consumers' cultured meat perception, respondents were assigned to one of five naming conditions for cultured meat. The clusters analysis yielded three clusters, two of which showed moderate WTC cultured meat. The first cluster could be characterized as "meat lovers." Their WTC was strongest for conventional meat, followed by cultured meat, and tastiness was their main driver of WTC. The second cluster's preference was fish, followed by PBMA, with naturalness, safety, and tastiness being their drivers of WTC. The third cluster's highest WTC was for PBMA, followed by cultured meat. Among their drivers of WTC were healthiness, sustainability, and animal friendliness. Psychographic variables were highly valuable in explaining the clusters. Finally, no effects of naming for cultured meat were observed. PRACTICAL APPLICATION: The results contribute to the design of guidelines to promote different meat alternatives considering specific target populations., (© 2022 The Authors. Journal of Food Science published by Wiley Periodicals LLC on behalf of Institute of Food Technologists.)
- Published
- 2023
- Full Text
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19. How Does Variation in the Body Composition of Both Stimuli and Participant Modulate Self-Estimates of Men's Body Size?
- Author
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Groves V, Cornelissen P, McCarty K, Mohamed S, Maalin N, Tovée MJ, and Cornelissen K
- Abstract
When measured in units of body mass index (BMI), how much variation in men's self-estimates of body size is caused by i) variation in participants' body composition and ii) variation in the apparent muscle mass and muscle tone of the stimuli being judged? To address this, we generated nine sets of male CGI bodies representing low, mid, and high muscle mass rendered at low, mid, and high muscle tone, from 18.75 to 40 BMI
hse units. BMIhse units in this study are estimates of BMI derived from calibration equations predicting BMI from waist and hip circumference, age, sex, height, and ethnicity in the Health Survey for England databases. Forty-five healthy adult men estimated their body size using a yes-no paradigm for each combination of muscle mass/tone. We also measured participants' body composition with Harpenden callipers and their body concerns with psychometric questionnaires. We show that stimulus variation in apparent muscle mass/tone can introduce differences up to ∼2.5 BMIhse units in men's self-estimates of body size. Moreover, men with the same actual BMI, but different body composition, showed up to ∼5-7 BMIhse unit differences in self-estimates of body size. In the face of such large errors, we advocate that such judgments in men should be made instead by simultaneously manipulating both the adiposity and the muscle mass of stimuli which are appropriately calibrated for body composition, so that the participant can match the body size and shape they believe themselves to have to the stimulus they see., (Copyright © 2019 Groves, Cornelissen, McCarty, Mohamed, Maalin, Tovée and Cornelissen.)- Published
- 2019
- Full Text
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20. Relative contributions of presystemic and systemic peptidases to oral exposure of a novel metabotropic glutamate 2/3 receptor agonist (LY404039) after oral administration of prodrug pomaglumetad methionil (LY2140023).
- Author
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Annes WF, Long A, Witcher JW, Ayan-Oshodi MA, Knadler MP, Zhang W, Mitchell MI, Cornelissen K, and Hall SD
- Subjects
- Activation, Metabolic, Administration, Oral, Adult, Amino Acids administration & dosage, Amino Acids adverse effects, Amino Acids analysis, Antipsychotic Agents administration & dosage, Antipsychotic Agents adverse effects, Antipsychotic Agents analysis, Biological Availability, Bridged Bicyclo Compounds, Heterocyclic administration & dosage, Bridged Bicyclo Compounds, Heterocyclic adverse effects, Bridged Bicyclo Compounds, Heterocyclic analysis, Carbon Radioisotopes, Cross-Over Studies, Cyclic S-Oxides administration & dosage, Cyclic S-Oxides adverse effects, Cyclic S-Oxides analysis, Dose-Response Relationship, Drug, Feces chemistry, Humans, Infusions, Intravenous, Intestinal Mucosa enzymology, Intestinal Mucosa metabolism, Male, Middle Aged, Prodrugs administration & dosage, Prodrugs adverse effects, Prodrugs analysis, Receptors, Metabotropic Glutamate agonists, Receptors, Metabotropic Glutamate metabolism, Young Adult, Amino Acids pharmacokinetics, Antipsychotic Agents pharmacokinetics, Bridged Bicyclo Compounds, Heterocyclic pharmacokinetics, Cyclic S-Oxides pharmacokinetics, Models, Biological, Peptide Hydrolases metabolism, Prodrugs pharmacokinetics
- Abstract
Pomaglumetad methionil (LY2140023) is the prodrug of a novel metabotropic glutamate 2/3 receptor agonist (LY404039) being investigated for the treatment of schizophrenia. Using accelerator mass spectrometry (AMS) and an intravenous (i.v.) radiolabeled tracer approach, the absolute bioavailability of the prodrug and the extent of its conversion to active moiety (LY404039) were estimated at presystemic (intestinal/first pass) and systemic sites after simultaneous oral and i.v. dosing in healthy subjects. The mean absolute bioavailability of prodrug (80 mg oral) was 0.68. On the basis of these data and a previous radiolabeled mass balance study in which no prodrug was recovered in feces, we concluded that 0.32 of the dose is converted to active drug in the intestinal tract. The fraction of prodrug converted to active moiety was approximately 1, indicating complete conversion of the prodrug that reaches the systemic circulation to the active moiety. Prodrug (80 mg oral and 100 μg i.v.) and active moiety (100 μg i.v.) were well tolerated in healthy subjects. Thus, the absolute bioavailability of prodrug LY2140023 and the fraction converted presystemically and systemically to active moiety LY404039 were estimated simultaneously using radiolabeled tracer microdosing and AMS., (© 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.)
- Published
- 2015
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21. An algorithm-based topographical biomaterials library to instruct cell fate.
- Author
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Unadkat HV, Hulsman M, Cornelissen K, Papenburg BJ, Truckenmüller RK, Carpenter AE, Wessling M, Post GF, Uetz M, Reinders MJ, Stamatialis D, van Blitterswijk CA, and de Boer J
- Subjects
- Cell Proliferation, Databases, Factual, High-Throughput Screening Assays methods, Humans, Mesenchymal Stem Cells cytology, Microscopy, Confocal, Microscopy, Electron, Scanning, Microscopy, Fluorescence, Polyesters, Algorithms, Biocompatible Materials, Lactic Acid chemistry, Mesenchymal Stem Cells physiology, Polymers chemistry, Surface Properties
- Abstract
It is increasingly recognized that material surface topography is able to evoke specific cellular responses, endowing materials with instructive properties that were formerly reserved for growth factors. This opens the window to improve upon, in a cost-effective manner, biological performance of any surface used in the human body. Unfortunately, the interplay between surface topographies and cell behavior is complex and still incompletely understood. Rational approaches to search for bioactive surfaces will therefore omit previously unperceived interactions. Hence, in the present study, we use mathematical algorithms to design nonbiased, random surface features and produce chips of poly(lactic acid) with 2,176 different topographies. With human mesenchymal stromal cells (hMSCs) grown on the chips and using high-content imaging, we reveal unique, formerly unknown, surface topographies that are able to induce MSC proliferation or osteogenic differentiation. Moreover, we correlate parameters of the mathematical algorithms to cellular responses, which yield novel design criteria for these particular parameters. In conclusion, we demonstrate that randomized libraries of surface topographies can be broadly applied to unravel the interplay between cells and surface topography and to find improved material surfaces.
- Published
- 2011
- Full Text
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22. Phase I safety, tolerability, and pharmacokinetic study of recombinant human mannan-binding lectin.
- Author
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Petersen KA, Matthiesen F, Agger T, Kongerslev L, Thiel S, Cornelissen K, and Axelsen M
- Subjects
- Adolescent, Adult, Dose-Response Relationship, Drug, Double-Blind Method, Half-Life, Humans, Male, Mannose-Binding Lectin blood, Middle Aged, Recombinant Proteins, Immunologic Deficiency Syndromes drug therapy, Mannose-Binding Lectin deficiency, Mannose-Binding Lectin pharmacology
- Abstract
Mannan-binding lectin (MBL), a human plasma protein, plays an important role in the innate immune defence. MBL recognizes microorganisms through surface carbohydrate structures. Due to genetic polymorphisms, MBL plasma concentrations range from 5 to 10,000 ng/mL. Approximately 30% of the human population have low levels of MBL (below 500 ng/mL). MBL deficiency is associated with increased susceptibility to infections in immunosuppressed individuals, e.g., during chemotherapeutically induced neutropenia. Replacement therapy with MBL may be beneficial in this patient group, and recombinant human MBL (rhMBL) is in development as a novel therapeutic approach. To assess the safety, tolerability, and pharmacokinetics of rhMBL, a placebo-controlled double-blinded study was performed in MBL-deficient healthy male subjects. rhMBL was administered as both single intravenous (i.v.) infusions (0.01, 0.05, 0.1, and 0.5 mg/kg) and repeated i.v. infusions (0.1 or 0.3 mg/kg given at 3-day intervals). There were no difference in incidence and type of adverse events reported in the study between the groups of subjects receiving rhMBL and the placebo group. All adverse events reported as drug-related were mild and no serious adverse events were recorded. There were no clinically significant changes in laboratory evaluations, ECG or vital signs, and no anti-MBL antibodies were detected following rhMBL administration. After single i.v. doses of rhMBL the maximal plasma levels increased in a dose-dependent manner reaching a geometric mean of 9710 ng/mL+/-10.5% in the highest dose group (0.5 mg/kg), with an elimination half-life of approximately 30 h. No rhMBL accumulation in plasma was observed following repeat dosing. Administration of rhMBL restored the ability to activate the MBL pathway of the complement system without non-specific activation of the complement cascade. In conclusion, no safety or tolerability concern was raised following rhMBL administration no signs of immunogenicity detected, and an rhMBL plasma level judged sufficient to achieve therapeutic benefit (>1000 ng/mL) can be achieved.
- Published
- 2006
- Full Text
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23. Learning new names for new objects: cortical effects as measured by magnetoencephalography.
- Author
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Cornelissen K, Laine M, Renvall K, Saarinen T, Martin N, and Salmelin R
- Subjects
- Adult, Humans, Male, Neuronal Plasticity, Parietal Lobe physiology, Cerebral Cortex physiology, Language, Learning physiology, Magnetoencephalography
- Abstract
We tracked the evolvement of naming-related cortical dynamics with magnetoencephalography when five normal adults successfully learned names and/or meanings of unfamiliar objects. In all subjects, the learning of new names was associated with pronounced cortical effects. The learning effect was of long latency and emerged as a change of activation in the same cortical network that was active during naming of familiar items. In four out of five subjects, the cortical learning effect occurred in the inferior parietal lobe. In three of these subjects, the cortical effect was left-sided. These results suggest that the inferior parietal lobe plays an important role in the acquisition of novel words, presumably as a part of working memory systems.
- Published
- 2004
- Full Text
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24. Naming actions and objects: cortical dynamics in healthy adults and in an anomic patient with a dissociation in action/object naming.
- Author
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Sörös P, Cornelissen K, Laine M, and Salmelin R
- Subjects
- Adult, Brain Mapping, Female, Humans, Image Processing, Computer-Assisted, Imaging, Three-Dimensional, Language Tests, Magnetic Resonance Imaging, Male, Middle Aged, Nerve Net physiopathology, Neuropsychological Tests, Reaction Time physiology, Reference Values, Signal Processing, Computer-Assisted, Anomia physiopathology, Cerebral Cortex physiopathology, Dominance, Cerebral physiology, Magnetoencephalography, Pattern Recognition, Visual physiology, Semantics, Verbal Behavior physiology
- Abstract
Neuropsychological studies have demonstrated that the production of nouns and verbs can be dissociated in aphasia. These reports have been taken as evidence for separate representations of nouns and verbs in the human brain. We used whole-head magnetoencephalography to record cortical dynamics of action and object naming in 10 healthy adults and in 1 anomic patient with superior naming of verbs compared with nouns due to a left posterior parietal lesion. A single set of 100 line drawings was used for both action and object naming. In normal subjects, the activation sequences in action and object naming were essentially identical, advancing from the occipital to posterior temporoparietal and further to the left frontal cortex, without consistent involvement of the classical left inferior frontal (Broca) and temporal (Wernicke) language areas. In the anomic patient, pronounced differences between action and object naming emerged in the left hemisphere. The activation sequence was disrupted at the level of the damaged parietal cortex and did not reach the left frontal cortex even in the relatively easier action naming. The more severely impaired object naming was associated with exceptionally strong and early activation of the left inferior frontal cortex (Broca) and subsequent pronounced activation of the left middle temporal cortex, silent in action naming. Verb and noun retrieval thus utilized a spatiotemporally similar neuronal network in healthy individuals. A clear dissociation in cortical correlates of verb and noun retrieval only became evident in our anomic patient, in whom damage to the language network has resulted in disproportionately worse performance in object than action naming.
- Published
- 2003
- Full Text
- View/download PDF
25. Adult brain plasticity elicited by anomia treatment.
- Author
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Cornelissen K, Laine M, Tarkiainen A, Järvensivu T, Martin N, and Salmelin R
- Subjects
- Humans, Magnetoencephalography, Male, Middle Aged, Aphasia physiopathology, Brain physiopathology, Language, Learning, Neuronal Plasticity, Vocabulary
- Abstract
We describe a study where a specific treatment method for word-finding difficulty (so-called contextual priming technique, which combines massive repetition priming with semantic priming) was applied with three chronic left hemisphere-damaged aphasics. Both before and after treatment, which focused on naming of a series of pictures, naming-related brain activity was measured by magnetoencephalography (MEG). Due to its excellent temporal resolution and good spatial resolution, we were able to track treatment-induced changes in cortical activity. All three subjects showed improved naming of the trained items. In all subjects, a single source area, located in the left inferior parietal lobe, close to the lesioned area, displayed statistically significant training-induced changes. This effect was of long latency as it started 300-600 msec after picture presentation. The change in activation was specific to training, as it could not be accounted for by variation of cortical dynamics associated with increased proportion of correct answers. Our interpretation is that the training effect reflects more effective phonological encoding and storage of the trained items through the engagement of a left hemispheric word-learning system. This is in line with recent functional imaging studies, which have linked left inferior parietal lobe activity to the phonological storage component of the verbal working memory, as well as with theoretical arguments stating that the primary role of the phonological loop is to acquire new words. Finally, the MEG results showed no evidence of increased right hemisphere participation following training, supporting the view that restoration of language-related networks in the damaged left hemisphere is crucial for anomia recovery.
- Published
- 2003
- Full Text
- View/download PDF
26. Naming multiple objects: neural correlates as measured by positron emission tomography.
- Author
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Renvall K, Laine M, Hiltunen J, Rinne JO, Kaasinen V, Sipilä H, Cornelissen K, and Martin N
- Subjects
- Adult, Anomia, Female, Humans, Male, Regional Blood Flow, Tomography, Emission-Computed, Visual Perception, Brain Mapping, Cerebral Cortex blood supply, Cerebral Cortex physiology, Semantics
- Abstract
The aim of this study was to examine the neural substrates of multi-object naming by positron emission tomography in normals. Multi-object naming is used in a technique called contextual priming (CP) to elicit contextual effects on picture naming through systematic manipulation of the relatedness of to-be-named pictures in an array. Inhibitory and facilitatory effects of CP on naming have been used both to highlight the inner dynamics of the normal word retrieval system and to treat naming difficulties caused by acquired anomia. Because of the complexity of the CP technique, it is unclear whether it merely reflects lexical retrieval or whether it also recruits general cognitive resources such as attentional control and response selection to a significant degree. When compared with a baseline situation in which colored circles were named, multi-object naming elicited increased blood flow in the occipital lobe and in the left inferior temporal and fusiform gyri. These areas have been related to visual pattern recognition and semantic access, and the pattern of activation is in line with previous functional imaging studies on single picture naming. In conclusion, multi-object naming does not appear to activate brain regions beyond those needed for single object naming. These findings thus provide independent evidence for the claim that CP is a valid paradigm for the study of word production proper.
- Published
- 2003
- Full Text
- View/download PDF
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