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1.
Tijdschr Psychiatr ; 59(1): 40-46, 2017.
Article in Dutch | MEDLINE | ID: mdl-28098923

ABSTRACT

BACKGROUND: Patients with schizophrenia frequently have depressive symptoms. Current guidelines do not provide specific recommendations regarding the treatment of these symptoms, nor do they mention the role that selective serotonin reuptake inhibitors (ssris) can play in the treatment.
AIM: To investigate whether ssris are more effective than placebo in treating depressive symptoms in patients with schizophrenia.
METHOD: We searched the literature systematically using PubMed, embase, Cochrane Library and Psycinfo. We selected articles on the basis of inclusion and exclusion criteria and the methodologies used and compared the severity of patients symptoms before and after treatment.
RESULTS: We found only four published studies of randomised, double blind, placebo-controlled trials. These showed that an ssri was significantly more effective than a placebo (the difference being 0.4 - 6.7 points on the Hamilton Depression Rating Scale and 0.2 - 2.6 on the Calgary Depression Scale for Schizophrenia).
CONCLUSION: There are indications that ssris are effective for the treatment of depressive symptoms in patients with schizophrenia. However, the total sample size was limited and individual studies had several methodological limitations.


Subject(s)
Depression/drug therapy , Schizophrenia/drug therapy , Selective Serotonin Reuptake Inhibitors/therapeutic use , Humans , Randomized Controlled Trials as Topic , Treatment Outcome
2.
Rev Sci Tech ; 35(2): 405-416, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27917983

ABSTRACT

This paper argues that pastoral commons are under increasing pressure not just from overuse by pastoralists themselves, but from land management policies. Since colonial times, these have been based on a persistent misconception of the nature of pastoral economies and combined with increasing land alienation and fragmentation through government policies and covert privatisation of pastures. The paper focuses especially on pastoral populations in African drylands and is based on long-term research by independent researchers summarising some of their experiences in western, eastern and southern Africa. Most of them are organised in the African Drylands Dialogue, trying to shed some light on the developments in these areas. Before discussing the actual situation of African pastoralists, the authors focus on basic institutional features of the political and economic management of common grazing lands. This is followed by an overview of land alienation processes in colonial times, which serves as a basis for understanding the current land alienation constellations. The paper then moves on to explain how and why pastoralists are framed by the national discourses as the 'other' and the 'troublemaker', even being labelled as terrorists in nation state contexts. This goes hand in hand with a new wave of land alienation in the form of large-scale land acquisitions or 'land grabbing' (including water grabbing and 'green grabbing' processes). The paper then outlines different coping and adaptation strategies adopted by pastoral groups in a context in which a range of different global and local political, economic and ecological situations interrelate ('glocal'). Finally, the paper discusses the way in which pastoralism could be reframed in a participatory way in the future.


Les auteurs de cet article soutiennent que la pression foncière croissante exercée sur les terres collectives pastorales n'est pas seulement imputable à la surexploitation par les pasteurs eux-mêmes mais résulte surtout des politiques de gestion des terres. Depuis le temps des colonies, ces politiques ont reposé sur une perception erronée et tenace de la nature même des économies pastorales, à laquelle se sont greffées l'aliénation croissante des terres et leur fragmentation impulsée par les politiques gouvernementales et par la privatisation dissimulée des prairies. Les auteurs s'intéressent particulièrement aux populations pastorales des régions arides d'Afrique et exposent les conclusions d'une étude conduite sur une longue durée par une équipe indépendante de chercheurs, résumant l'essentiel de leurs observations en Afrique de l'Ouest, de l'Est et australe. La plupart d'entre eux oeuvrent sous les auspices d'African Drylands Dialogue et tentent de faire la lumière sur les évolutions constatées dans ces régions. Avant de se pencher sur la situation des pasteurs africains aujourd'hui, les auteurs décrivent les principales caractéristiques institutionnelles de la gestion politique et économique des terres collectives dédiées au pâturage. Ils retracent ensuite les processus d'aliénation des terres opérés durant l'époque coloniale, qui servent de grille de lecture pour mieux comprendre les constellations actuelles de terres aliénées. Puis les auteurs expliquent comment et pourquoi les discours nationaux désignent les pasteurs comme « l'autre ¼ et le « fauteur de troubles ¼, quand ils ne les dépeignent pas comme des terroristes dans les contextes d'étatsnations. Ces accusations sont indissociables d'une nouvelle vague d'aliénation des terres, qui prend la forme d'acquisitions à grande échelle ou de réquisitions (y compris les processus d'appropriation des cours d'eau ou d'écosystèmes [green grabbing]). Les auteurs détaillent les stratégies mises en oeuvre par les groupes pastoraux pour faire face à cette évolution et s'y adapter, dans un contexte de forte interaction entre de nombreuses situations politiques, économiques et écologiques de portée tant mondiale que locale (niveau dit « glocal ¼). Enfin, les auteurs examinent les perspectives d'avenir du pastoralisme à travers un nouveau cadre de type participatif.


Los autores postulan que el patrimonio pastoral común se encuentra sometido a presiones crecientes, no solo a resultas de su explotación excesiva por parte de los propios pastores, sino también a consecuencia de las políticas de ordenación del territorio. Desde los tiempos coloniales, estas se basan en un equívoco pertinaz acerca del carácter de las economías pastorales, a lo que se suma un nivel creciente de enajenación y fragmentación de las tierras a resultas de las políticas públicas y la privatización encubierta de los pastos. Los autores prestan especial atención a las poblaciones pastorales de las tierras áridas africanas, basándose en investigaciones de larga duración realizadas por investigadores independientes y resumiendo parte de su experiencia en el África occidental, oriental y meridional. La mayoría de ellos están adscritos al African Drylands Dialogue [diálogo sobre las tierras áridas africanas] y tratan por esta vía de arrojar luz sobre la evolución de esas zonas. Antes de presentar la situación real de las sociedades de pastores africanas, los autores se detienen en una serie de rasgos institucionales básicos de la gestión política y económica de los pastizales de propiedad común. A continuación exponen a grandes líneas los procesos de enajenación de las tierras en la época colonial, que encierran elementos básicos para comprender la actual constelación de tierras enajenadas. Después pasan a explicar cómo y por qué en el discurso de ciertos países las sociedades de pastores han acabado representando la alteridad, percibida además como «agitadora¼, hasta llegar a ser etiquetadas de «terroristas¼ en algunos estados-nación, paralelamente a una nueva oleada de enajenación de tierras en forma de adquisiciones a gran escala o «acaparamiento de tierras¼ (lo que incluye procesos de acaparamiento del agua y «acaparamiento ecológico¼). Tras exponer diferentes estrategias de respuesta y adaptación adoptadas por los grupos pastorales en un contexto marcado por la imbricación entre diversas realidades políticas, económicas y ecológicas («glocal¼), los autores concluyen reflexionando sobre el modo en que en el futuro sería posible reestructurar el pastoreo pasando por métodos participativos.


Subject(s)
Animal Husbandry/trends , Colonialism , Internationality , Adaptation, Psychological , Africa , Animal Husbandry/methods , Animals , Humans
3.
Prog Brain Res ; 229: 367-388, 2016.
Article in English | MEDLINE | ID: mdl-27926448

ABSTRACT

This proof-of-concept study aimed to test whether competition could be a useful tool to increase intensity and amount of self-directed training in neurorehabilitation. Stroke patients undergoing inpatient neurorehabilitation (n=93) conducted self-directed endurance training on a (wheelchair-compatible) bicycle trainer under three experimental conditions: a "Competition" condition and two noncompetition control conditions (repeated randomized within-subject design). Training performance and perceived exertion were recorded and statistically analyzed. Three motivational effects of competition were found. First, competition led to an increase in self-directed training. Patients exercised significantly more intensively under competition than in the two noncompetition control conditions. Second, (winning a) competition had a positive influence on performance in the subsequent training session. Third, training performance was particularly high during rematch competitions; that is to say, during second encounter competitions against an opponent that the patient had just beaten. No systematic effect of competition upon perceived exertion (controlled for training performance) was found. Together, our results demonstrate that competition is a potent motivational tool to increase self-directed training in neurorehabilitation.


Subject(s)
Competitive Behavior/physiology , Motivation/physiology , Neurological Rehabilitation/methods , Self Efficacy , Stroke/physiopathology , Stroke/psychology , Aged , Bicycling/physiology , Cross-Over Studies , Female , Humans , Male , Middle Aged , Physical Endurance , Physical Therapy Modalities , Prospective Studies , Psychomotor Performance
4.
J Evol Biol ; 27(8): 1572-81, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24835689

ABSTRACT

Sea beets grown from seeds collected in 1989 and 2009 along the coasts of France and adjacent regions were compared for flowering date under controlled conditions. Seeds from both collection years were sown simultaneously and cultivated under the same glasshouse conditions. Date of flowering onset and year of first flowering were recorded. There was an overall northward shift in flowering time of about 0.35° latitude (i.e. 39 km) over the 20-year period. The southern portion of the latitudinal gradient--that is, from 44.7°N to 47.28°N--flowered significantly later by a mean of 1.78 days, equivalent to a 43.2-km northward shift of phenotypes. In the northern latitudes between 48.6°N and 52°N, flowering date was significantly earlier by a mean of 4.04 days, corresponding to a mean northward shift of 104.9 km, and this shift was apparently due to a diminished requirement of exposure to cold temperatures (i.e. vernalization), for which we found direct and indirect evidence. As all plants were grown from seed under identical conditions, we conclude that genetic changes occurred in the sensitivity to environmental cues that mediate the onset of flowering in both the northern and the southern latitudes of the gradient. Microevolution and gene flow may have contributed to this change. There was no significant change in the frequency of plants that flowered without vernalization. The lack of vernalization requirement may be associated with environmental instability rather than with climate conditions.


Subject(s)
Adaptation, Biological/genetics , Beta vulgaris/genetics , Cold Temperature , Flowers/genetics , Genetic Variation , France , Gene Flow , Geography , Time Factors
5.
Tijdschr Gerontol Geriatr ; 44(2): 50-8, 2013 Apr.
Article in Dutch | MEDLINE | ID: mdl-23463407

ABSTRACT

PURPOSE OF THE STUDY: We aimed to investigate whether social capital (obtaining support through indirect ties such as from neighbors) and social cohesion (interdependencies among neighbors) within neighborhoods positively affect the well-being of older adults. DESIGN AND METHODS: This cross-sectional study included 945/1440 (66 % response rate) independently living older adults (aged >70 years) in Rotterdam. We fitted a hierarchical random-effects model to account for the hierarchical structure of the study design: 945 older adults (level 1) nested in 72 neighborhoods (level 2). RESULTS: Univariate analyses showed that being born in the Netherlands, house ownership, education, income, social capital of individuals, neighborhood security, neighborhood services, neighborhood social capital, and neighborhood social cohesion were significantly related to the well-being of older adults. Multilevel analyses showed that social capital of individuals, neighborhood services, neighborhood social capital, and neighborhood social cohesion predicted the well-being of older adults. Single and poor older adults reported lower well-being than did better-off and married older adults. However, the effects of marital status and income were mediated by neighborhood services, social capital, and social cohesion. Neighborhood services, social capital and social cohesion may act as buffer against the adverse effects of being single and poor on the well-being of older adults. IMPLICATIONS: The results of this study support the importance of social capital of individuals, as well as social capital within the neighborhood and social cohesion within the neighborhood for well-being of older adults. The well-being of older adults may also be enhanced through the improvement of quality of neighborhood services.


Subject(s)
Aging/psychology , Health Status , Social Class , Social Support , Aged , Aged, 80 and over , Aging/physiology , Community Networks , Cross-Sectional Studies , Female , Humans , Interpersonal Relations , Male , Mental Health , Netherlands , Residence Characteristics , Social Environment , Social Participation , Socioeconomic Factors
6.
Risk Anal ; 27(6): 1565-80, 2007 Dec.
Article in English | MEDLINE | ID: mdl-18093053

ABSTRACT

In developing and implementing appropriate food risk management strategies, it is important to understand how consumers evaluate the quality of food risk management practices. The aim of this study is to model the underlying psychological factors influencing consumer evaluations of food risk management quality using structural equation modeling techniques (SEM), and to examine the extent to which the influence of these factors is country-specific (comparing respondents from Denmark, Germany, Greece, Slovenia, and the United Kingdom). A survey was developed to model the factors that drive consumer evaluations of food risk management practices and their relative importance (n= 2,533 total respondents). The measurement scales included in the structural model were configurally and metrically invariant across countries. Results show that some factors appear to drive perceptions of effective food risk management in all the countries studied, such as proactive consumer protection, which was positively related to consumers' evaluation of food risk management quality, while opaque and reactive risk management was negatively related to perceived food risk management quality. Other factors appeared to apply only in certain countries. For example, skepticism in risk assessment and communication practices was negatively related to food risk management quality, particularly so in the UK. Expertise of food risk managers appeared to be a key factor in consumers' evaluation of food risk management quality in some countries. However, trust in the honesty of food risk managers did not have a significant effect on food risk management quality. From the results, policy implications for food risk management are discussed and important directions for future research are identified.


Subject(s)
Food , Risk Management , Animals , Community Participation , Europe , Food/adverse effects , Food/standards , Food Supply/standards , Humans , Models, Statistical , Regression Analysis , Risk Management/standards , Risk Management/statistics & numerical data , Safety , Trust
7.
J Evol Biol ; 20(1): 349-57, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17210028

ABSTRACT

Day length is a key factor in flowering induction in many plant species in a seasonal environment with flowering induction usually happening at shorter day lengths in lower latitudes. Now, the climate changes systematically at a considerable speed due to global warming. As a consequence, earlier flowering will be selected for in long day plants by favouring a lower threshold for day length sensitivity, on the condition of available genetic variability. Here, we show that there is considerable genetic variation for day length sensitivity in our study species, the seabeet Beta vulgaris subsp. maritima. In the northernmost natural populations without vernalization requirement, in southwest France, the necessary day length for flowering induction could be reduced by artificial selection in <10 generations from >13 h to <11 h, the latter value corresponding to populations in the Beta-species complex from Northern Africa and the eastern part of the Mediterranean tested under the same conditions. A quantitative genetic analysis provided evidence of a gradual change without detectable major genes. Additional experiments were carried out to separate the response to photoperiod from age and energy effects. A certain effect of energy availability has been found, whereas age effects could be excluded. These results indicate a considerable potential for evolutionary change in adjusting flowering time in a changing climate.


Subject(s)
Adaptation, Physiological , Beta vulgaris/physiology , Flowers/physiology , Genetic Variation , Photoperiod , Age Factors , Beta vulgaris/genetics , Crosses, Genetic , Geography , Mediterranean Region , Models, Genetic , Selection, Genetic
8.
J Telemed Telecare ; 12(6): 289-97, 2006.
Article in English | MEDLINE | ID: mdl-17022836

ABSTRACT

We reviewed the methodology used in telemedicine research concerning patients with postural and movement disorders. Literature searches were performed using various computerized databases through to October 2005. Twenty-two studies met the criteria for review. Two broad models of telemedicine delivery were represented in the literature: (1) telemedicine between health-care professionals at each telemedicine site (n=16) and (2) telemedicine between health-care professionals and a patient at a remote site (n=6). Disparate research methodologies were used to investigate these two models. Most studies were limited to investigating the technical feasibility and acceptability of a telemedicine service rather than focusing on the overall effect of introducing the telemedicine service into routine health care. Nonetheless, it is possible to conclude that telemedicine is acceptable for both patients and professionals when used in rehabilitation. Since the two models of telemedicine evaluation tend to explore different outcomes (diagnostic accuracy versus health status), it is recommended that separate methodologies should be used. In contrast to evaluations of telemedicine model 2, randomized controlled trials appear to be less valuable for telemedicine model 1.


Subject(s)
Delivery of Health Care/standards , Movement Disorders/therapy , Posture , Telemedicine/standards , Delivery of Health Care/methods , Humans , Movement Disorders/diagnosis , Program Evaluation/standards , Quality of Health Care/standards , Randomized Controlled Trials as Topic , Research/standards
9.
Appl Psychophysiol Biofeedback ; 31(3): 243-52, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16906467

ABSTRACT

The aim was to investigate the influence of mood on learning muscle relaxation. Self-reported mood (assessed by the Stress-Energy Checklist) at baseline was related to learning muscle relaxation induced by electromyographic feedback training during performance of a gross-motor task. Feedback training was provided either intermittently (Intermittent Feedback Task, IF, n=12) or continuously (Continuous Feedback Task, CF, n=9). Results reveal a negative correlation between the learning effect at short-term and energy dimension for the IF Task. It can be concluded that mood experienced prior to a learning task is relevant for the learning effect and this effect may be dependent on the schedule of feedback used.


Subject(s)
Biofeedback, Psychology/methods , Electromyography , Energy Metabolism/physiology , Learning/physiology , Muscle Relaxation/physiology , Psychomotor Performance/physiology , Stress, Psychological/physiopathology , Adult , Affect/physiology , Biofeedback, Psychology/instrumentation , Cross-Sectional Studies , Data Interpretation, Statistical , Female , Humans , Male , Memory/physiology , Psychometrics , Reinforcement Schedule
10.
Eur J Clin Invest ; 35(8): 531-4, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16101674

ABSTRACT

BACKGROUND: Polymorphisms in the mannose-binding lectin gene reduce serum mannose-binding lectin levels and are associated with enhanced risk of infection. In a family with recurrent staphylococcal disease presenting as furunculosis or carbuncles, an association with mannose-binding lectin deficiency was investigated. MATERIALS AND METHODS: Levels of functional mannose-binding lectin were estimated and the genotypes of the mannose-binding lectin gene were analysed on blood samples, collected from the members of one particular family with a high prevalence of furunculosis. RESULTS: Functional mannose-binding lectin levels in sera of 13 of the 28 members of one family showed deficiency. Furunculosis or carbuncles appeared to be present in nine of the 28 family members, seven of which showing the pBly allele and mannose-binding lectin deficiency. Four young family members of the second generation were pBly positive and mannose-binding lectin deficient, but had not shown furunculosis yet. CONCLUSION: Members of a particular family suffering from furunculosis differ from their 'healthy' relatives as to mannose-binding lectin genotypes, indicating the relevance of normal mannose-binding lectin levels in the defence against staphylococcal disease.


Subject(s)
Furunculosis/genetics , Mannose-Binding Lectin/deficiency , Adolescent , Adult , Complement System Proteins/analysis , Family Health , Female , Genotype , Humans , Immunoglobulins/blood , Male , Mannose-Binding Lectin/blood , Mannose-Binding Lectin/genetics , Middle Aged , Pedigree
11.
J Evol Biol ; 18(3): 676-82, 2005 May.
Article in English | MEDLINE | ID: mdl-15842497

ABSTRACT

When genes in the offspring control the provisioning of the seed, the optimal seed size can be calculated exactly by applying Hamilton's rule. When seed size is a compromise between mother and offspring, we predict that outcrossing plant species produce larger seeds than selfers. This trend was found in the British flora and in a number of well-studied plant families. The analysis was extended to imprinting, a conditional strategy in which a gene in the offspring takes more resources when derived from the father than from the mother. The conditions for imprinting to be selected were rather restrictive. The analysis is relevant for the current debate about the evolution of imprinting in Arabidopsis thaliana.


Subject(s)
Genes, Plant/physiology , Genomic Imprinting/physiology , Models, Biological , Plant Physiological Phenomena , Seeds/cytology , Selection, Genetic , Arabidopsis , Genomic Imprinting/genetics , Reproduction/physiology
12.
Clin Diagn Lab Immunol ; 11(4): 806-7, 2004 Jul.
Article in English | MEDLINE | ID: mdl-15242964

ABSTRACT

In a recent report, our group presented clinical research data supporting the role of mannose-binding lectin (MBL) deficiency in susceptibility to meningococcal disease (W. A. Bax, O. J. J. Cluysenaer, A. K. M. Bartelink, P. C. Aerts, R. A. B. Ezekowitz, and H. van Dijk, Lancet 354:1094-1095, 1999). This association was reported earlier by Hibberd et al. (M. L. Hibberd, M. Sumiya, J. A. Summerfield, R. Booy, M. Levin, and the Meningococcal Research Group, Lancet 353:1049-1053, 1999) but was not based on family data. Our study included three members of one family who had acquired meningococcal meningitis in early adulthood. The objective of the present study was to investigate whether the genotypes of the MBL gene in this family, analyzed by PCR, correlate with MBL concentrations. We found that genotype variants in the MBL gene and promoter region match the low functional MBL levels (<0.25 microg of equivalents/ml) in the sera of the three patients in this family and that a significant correlation between genotype MBL deficiency and meningococcal disease existed.


Subject(s)
Genetic Predisposition to Disease , Mannose-Binding Lectin/deficiency , Mannose-Binding Lectin/genetics , Promoter Regions, Genetic/genetics , Female , Genotype , Humans , Male , Meningitis, Meningococcal/genetics , Mutation , Pedigree , Polymerase Chain Reaction
13.
J Telemed Telecare ; 10(2): 63-71, 2004.
Article in English | MEDLINE | ID: mdl-15068640

ABSTRACT

We reviewed the literature on distance training for the restoration of motor function. Computerized literature searches were performed using the MEDLINE, EMBASE, Cinahl and Cochrane databases. Articles that met the criteria for inclusion were divided into three general areas concerning the type of training in relation to motor functions--muscle/joint, balance and cognition. From the publications identified in the literature search, 11 articles met the selection criteria. Six were related to muscle/joint functions, four to balance functions and one to cognitive functions. The articles were graded according to the strength of the scientific evidence they offered. The review revealed some promising applications of distance motor training, such as virtual reality (VR) and robotic devices. The strength of the evidence from these studies was poor, however, probably because the technology is relatively new. In contrast to the studies using VR and robotic devices, those using electromyographic (EMG) biofeedback showed a good to fair strength of scientific evidence. This can be explained by the substantial history of research on the restoration of motor function through the use of EMG biofeedback techniques. When implemented in clinical practice, these applications could reduce the pressure on scarce health-care resources.


Subject(s)
Motor Skills Disorders/rehabilitation , Patient Education as Topic/organization & administration , Recovery of Function , Telemedicine/methods , Biofeedback, Psychology , Delivery of Health Care/organization & administration , Exercise Therapy/methods , Humans
14.
Arterioscler Thromb Vasc Biol ; 23(10): 1875-80, 2003 Oct 01.
Article in English | MEDLINE | ID: mdl-12933534

ABSTRACT

OBJECTIVE: An increased hepatic flow of free fatty acids (FFAs) is associated with impaired peripheral FFA trapping by malfunctioning of the complement component 3 (C3)/acylation-stimulating protein system and overproduction of VLDL in familial combined hyperlipidemia (FCHL). Postprandial ketone bodies reflect FFA oxidation in the liver, but the postprandial changes in male and female patients separately have not been determined yet. Gender differences in postprandial ketone bodies and C3 changes were investigated in normolipidemic patients and patients with untreated FCHL. METHODS AND RESULTS: Thirty-two normolipidemic patients (16 female and 16 male) and 19 patients with untreated normolipidemia (9 female and 10 male) underwent an oral fat-loading test. Total and incremental areas under the curves (AUC and dAUC, respectively) after the oral fat load were calculated. Triglyceride AUC was similar between genders in each group. Normolipidemic female subjects showed a higher levels of dAUC-hydroxybutyric acid than male subjects (1.37+/-0.49 and 0.98+/-0.43 mmol x h/L). In FCHL, a similar trend was observed in female (1.92+/-0.38) compared with male (1.55+/-0.87) subjects. In contrast to normolipidemia, FCHL did not show a postprandial increase in C3, although C3 was higher in FCHL. CONCLUSIONS: Women have higher postprandial ketone bodies than men, probably reflecting enhanced postprandial hepatic FFA oxidation. In FCHL, both genders have higher postprandial ketone bodies and therefore higher hepatic FFA delivery. The higher fasting and postprandial C3 levels in FCHL may reflect resistance of the C3/acylation-stimulating protein system to promote peripheral fatty acid trapping.


Subject(s)
Fatty Acids, Nonesterified/metabolism , Hyperlipidemia, Familial Combined/metabolism , Ketone Bodies/metabolism , 3-Hydroxybutyric Acid/blood , Adult , Area Under Curve , Complement C3/metabolism , Dietary Fats/administration & dosage , Dietary Fats/metabolism , Fatty Acids, Nonesterified/blood , Female , Humans , Hyperlipidemia, Familial Combined/blood , Male , Middle Aged , Postprandial Period , Sex Characteristics , Triglycerides/blood
15.
J Lipid Res ; 44(11): 2100-8, 2003 Nov.
Article in English | MEDLINE | ID: mdl-12923226

ABSTRACT

VLDL overproduction by enhanced hepatic FFA flux is a major characteristic of familial combined hyperlipidemia (FCHL). The postprandial complement component 3 (C3) response has been associated with impaired postprandial FFA metabolism in FCHL. We investigated the effects of 16 weeks of treatment with atorvastatin on postprandial C3 and lipid changes in 12 FCHL patients. Atorvastatin significantly lowered fasting plasma C3 and triglyceride (TG) in FCHL. Fasting TG and insulin sensitivity were the best predictors of fasting and postprandial C3. Postprandial triglyceridemia and C3 response, estimated as area under the curve (AUC), were significantly lowered by atorvastatin by 19% and 12%, respectively, albeit still elevated, compared with 10 matched controls. Postprandial FFA-AUC and postheparin plasma lipolytic activities remained unchanged after atorvastatin, suggesting no major effect on lipolysis. After atorvastatin, postprandial hydroxybutyric acid-AUC, which was elevated in untreated FCHL patients, was decreased, reaching values similar to those in controls. The present data show reduction of postprandial hepatic FFA flux in FCHL by atorvastatin, providing an additional mechanistic explanation for the reduction of VLDL secretion reported previously for atorvastatin. This was accompanied by a decrease in fasting plasma C3 concentrations and a blunted postprandial C3 response to an acute oral fat load.


Subject(s)
Anticholesteremic Agents/pharmacology , Complement C3/analysis , Fasting/blood , Heptanoic Acids/pharmacology , Hyperlipidemia, Familial Combined/blood , Postprandial Period/drug effects , Postprandial Period/physiology , Pyrroles/pharmacology , Apolipoproteins B/blood , Atorvastatin , Chylomicrons/blood , Fatty Acids, Nonesterified/metabolism , Female , Humans , Hyperlipidemia, Familial Combined/metabolism , Male , Triglycerides/blood
16.
Eur J Clin Invest ; 33(2): 169-75, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12588292

ABSTRACT

BACKGROUND: Human red blood cells bind various C3b-coated microorganisms via their C3b/CR1 receptor, a phenomenon referred to as immune adherence. The aim of the present study was to measure pneumococcal adherence to human red blood cells by flow cytometry and to study kinetic aspects of this binding. MATERIAL AND METHODS: We quantified pneumococcal adherence to human erythrocytes by FACS analysis and tested the involvement of antibodies and complement activation in this process. RESULTS: Pneumococci are able to bind to human red blood cells in the presence of human serum. Coating with C3b/C4b appeared obligatory for pneumococcal adherence to red blood cells. The ligand on erythrocytes was confirmed to be complement receptor 1. Kinetic studies showed that innate (mannose-binding lectin) and specific immune factors (IgG antibodies) contributed to the binding of C3b-coated pneumococci to human erythrocytes. After initial binding, serum-derived factor I was found to induce bacterial detachment from the erythrocyte. CONCLUSIONS: Pneumococci are able to adhere to red blood cells. Both the classical and lectin complement pathways are important for optimal C3b-coating of pneumococci for immune adherence. Bound pneumococci are detached from red blood cells by factor I. These findings are in line with the hypothesis of immune adherence in which human erythrocytes are able to bind pneumococci and target the bacteria to the reticulo-endothelial system in the spleen.


Subject(s)
Bacterial Adhesion/immunology , Erythrocytes/immunology , Streptococcus pneumoniae/immunology , Cell Adhesion/immunology , Complement Activation/immunology , Complement C3b/immunology , Complement C4b/immunology , Complement Factor I/immunology , Flow Cytometry , Humans , Immune Adherence Reaction , Immunoglobulin G , Mannose-Binding Lectin/immunology , Receptors, Complement/immunology
17.
Arterioscler Thromb Vasc Biol ; 22(5): 811-6, 2002 May 01.
Article in English | MEDLINE | ID: mdl-12006395

ABSTRACT

Very low density lipoprotein overproduction is the major metabolic characteristic in familial combined hyperlipidemia (FCHL). Peripheral handling of free fatty acids (FFAs) in vitro may be impaired in FCHL by decreased action of acylation-stimulating protein (ASP), which is identical to the immunologically inactive complement component 3a (C3adesArg). Because decreased FFA uptake by impaired complement component 3 (C3) response (as the precursor for ASP) may result in enhanced FFA flux to the liver in FCHL, we have evaluated postprandial C3 changes in vivo in FCHL patients. Accordingly, 10 untreated FCHL patients and 10 matched control subjects underwent an oral fat loading test. Fasting plasma C3 and ASP levels were higher in FCHL patients (1.33+/-0.09 g/L and 70.53+/-4.37 mmol/L, respectively) than in control subjects (0.91+/-0.03 g/L and 43.21+/-8.96 mmol/L, respectively; P=0.01 and P<0.05). In control subjects, C3 concentrations increased significantly after 4 hours (to 1.03+/-0.04 g/L). In FCHL, plasma C3 was unchanged after 4 hours. The earliest postprandial C3 rise in FCHL patients occurred after 8 hours (1.64+/-0.12 g/L). The maximal apolipoprotein B-48 concentration was reached after 6 hours in FCHL patients and control subjects. Postprandial FFA and hydroxybutyric acid (as a marker of hepatic FFA oxidation) were significantly higher in FCHL patients than in control subjects, and the early postprandial C3 rise was negatively correlated with the postprandial FFA and hydroxybutyric acid concentrations. The present data suggest an impaired postprandial plasma C3 response in FCHL patients, most likely as a result of a delayed response by C3, as the precursor for the biologically active ASP, acting on FFA metabolism. Therefore, an impaired postprandial C3 response may be associated with impaired peripheral postprandial FFA uptake and, consequently, lead to increased hepatic FFA flux and very low density lipoprotein overproduction.


Subject(s)
Complement C3/metabolism , Complement C3a/analogs & derivatives , Hyperlipidemia, Familial Combined/blood , Postprandial Period/physiology , Adult , Blood Proteins/metabolism , Cerebrovascular Disorders/blood , Chylomicrons/blood , Dietary Fats/metabolism , Fasting/blood , Fasting/metabolism , Fatty Acids, Nonesterified/blood , Female , Humans , Hydroxybutyrates/blood , Hyperlipidemias/blood , Male , Myocardial Infarction/blood , Triglycerides/blood
18.
Ned Tijdschr Geneeskd ; 146(3): 103-9, 2002 Jan 19.
Article in Dutch | MEDLINE | ID: mdl-11826668

ABSTRACT

Free fatty acids (FFAs) are involved in the transportation of energy; in the postprandial phase to the peripheral tissues and in the postabsorptive phase from the adipose tissue to the liver. In the postprandial phase, FFAs are mainly derived from hydrolysis of triglyceride-rich particles like chylomicrons and very low-density lipoproteins (VLDL). The flux of FFAs is directed to peripheral cells such as adipocytes and muscle cells. In the postabsorptive period, FFAs are transported to the liver after being released from intracellular storage in the adipocytes. Complement component 3 (C3) plays an important role in the uptake of free fatty acids by the peripheral cells and their esterification to triglycerides. Since C3 is also involved in the pathogenesis of the insulin resistance syndrome, and since a deviant FFA metabolism with an increased FFA flux to the liver may induce insulin resistance, it is hypothesized that C3 may form the missing link between FFA metabolism and insulin resistance. In addition, recent studies have increasingly indicated that atherosclerosis is in fact an inflammation-based process involving complement-dependent responses, in which FFAs seem to play a role in the complement-dependent pathway. It has recently become apparent that FFAs have a regulatory function in the transcription of DNA, in relation to lipoprotein metabolism. This is where PPAR-gamma and PPAR-alpha agonists ('glitazones' and fibrates respectively) are active (PPAR is an abbreviation for peroxisome proliferation activating receptor). Glitazons may play an important role in the treatment of insulin resistance and related disorders. Acquiring more knowledge about the relationship between complement and FFA metabolism may increase our understanding of these processes and provide openings for the development of new antiatherogenic strategies.


Subject(s)
Arteriosclerosis/metabolism , Complement C3/metabolism , Fatty Acids, Nonesterified/metabolism , Insulin Resistance , Thiazoles/pharmacology , Arteriosclerosis/etiology , Arteriosclerosis/physiopathology , Humans , Lipoproteins/metabolism , Receptors, Cytoplasmic and Nuclear/agonists , Transcription Factors/agonists , Triglycerides/biosynthesis
19.
New Phytol ; 154(3): 641-650, 2002 Jun.
Article in English | MEDLINE | ID: mdl-33873462

ABSTRACT

• Removal of developing fruits delays ageing in many annual plant species. This has long been seen as evidence that ageing is caused by resource depletion due to fruit development. Excision experiments can be interpreted from both evolutionary-ecology and resource-allocation viewpoints. Iteroparous (reproducing repeatedly) and annual plants may show different responses to excision. Furthermore, under the resource-depletion hypothesis, the more precocious the excision of reproductive organs, the greater the effect on allocation patterns. • A controlled-conditions experiment was set up involving six life cycles (from long-lived iteroparous to annual taxa of wild beets, Beta spp.) under three treatments of excision of reproductive-parts (buds, fruits and control). • Treatment effect was similar in semelparous and iteroparous beets, although effect on reproduction was more obvious in iteroparous ones. Flower-bud removal tended to induce resource allocation in new reproductive meristems, whatever the life cycle, without any effect on ageing in semelparous beets and probably none on survival in most iteroparous plants. Fruit removal had no effect. • These results and the occurrence of between-accessions variation are discussed in terms of the ecological significance of optimal allocation strategies.

20.
Int J Antimicrob Agents ; 18(4): 395-8, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11691576

ABSTRACT

Streptococcal pyrogenic exotoxins A (SPE-A) and B (SPE-B) have been implicated in the pathogenesis of serious group A streptococcal infections including streptococcal toxic shock-syndrome. Current antibiotics used for the treatment of these infections are penicillin and clindamycin. The effects of sub- and suprainhibitory concentrations of penicillin and clindamycin were evaluated in 14 isolates of Streptococcus pyogenes that were fully susceptible to both antibiotics. Clindamycin was superior to penicillin in reducing the production of SPE-A and SPE-B by invasive and non-invasive Dutch group A streptococcal isolates in vitro.


Subject(s)
Bacterial Proteins , Clindamycin/pharmacology , Exotoxins/biosynthesis , Membrane Proteins , Penicillins/pharmacology , Streptococcus pyogenes/drug effects , Streptococcus pyogenes/metabolism , Exotoxins/analysis , Humans , Microbial Sensitivity Tests , Netherlands , Streptococcal Infections/microbiology , Streptococcus pyogenes/growth & development
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