Maastricht University

About: Maastricht University is a education organization based out in Maastricht, Limburg, Netherlands. It is known for research contribution in the topics: Population & Health care. The organization has 19263 authors who have published 53291 publications receiving 2266866 citations. The organization is also known as: Universiteit Maastricht & UM.

Marketing service relationships: the role of commitment

Abstract: As with all relationships, it is commonly agreed on that partners in business must have a high degree of commitment towards their relationship. If commitment is lacking, the relationship will soon come to an end. Affective commitment, that is commitment based on attraction between partners, is to be preferred over calculative commitment. The latter form of commitment is based on constant weighing of the benefits of a relationship with a partner against the costs of that relationship. Relationships based solely on calculative commitment are also most likely not to last for an extended time. This paper identifies theoretical antecedents and consequences of commitment in relationships in a services context. The results of an empirical study reveal that affective commitment is related to trust in the partner’s honesty and benevolence, quality of the outcome of the service process, and customer satisfaction with the service being delivered. The quality of the service process has an indirect effect on affective commitment, as it is related to satisfaction. Furthermore, it is shown that affectively committed customers have a much stronger intention to stay in a relationship with a service provider than calculatively committed customers.

X-linked Alport Syndrome Natural History in 195 Families and Genotype- Phenotype Correlations in Males

Abstract: Alport syndrome (AS) is a type IV collagen hereditary disease characterized by the association of progressive hematuric nephritis, hearing loss, and, frequently, ocular changes. Mutations in the COL4A5 collagen gene are responsible for the more common X-linked dominant form of the disease. Considerable allelic heterogeneity has been observed. A "European Community Alport Syndrome Concerted Action" has been established to delineate accurately the AS phenotype and to determine genotype-phenotype correlations in a large number of families. Data concerning 329 families, 250 of them with an X-linked transmission, were collected. Characteristics of the 401 male patients belonging to the 195 families with COL4A5 mutation are presented. All male patients were hematuric, and the rate of progression to end-stage renal failure and deafness was mutation-dependent. Large deletions, non-sense mutations, or small mutations changing the reading frame conferred to affected male patients a 90% probability of developing end-stage renal failure before 30 yr of age, whereas the same risk was of 50 and 70%, respectively, in patients with missense or splice site mutation. The risk of developing hearing loss before 30 yr of age was approximately 60% in patients with missense mutations, contrary to 90% for the other types of mutations. The natural history of X-linked AS and correlations with COL4A5 mutations have been established in a large cohort of male patients. These data could be used for further evaluation of therapeutic approaches.

Paraoxonase-1 is a major determinant of clopidogrel efficacy

Abstract: Clinical efficacy of the antiplatelet drug clopidogrel is hampered by its variable biotransformation into the active metabolite. The variability in the clinical response to clopidogrel treatment has been attributed to genetic factors, but the specific genes and mechanisms underlying clopidogrel bioactivation remain unclear. Using in vitro metabolomic profiling techniques, we identified paraoxonase-1 (PON1) as the crucial enzyme for clopidogrel bioactivation, with its common Q192R polymorphism determining the rate of active metabolite formation. We tested the clinical relevance of the PON1 Q192R genotype in a population of individuals with coronary artery disease who underwent stent implantation and received clopidogrel therapy. PON1 QQ192 homozygous individuals showed a considerably higher risk than RR192 homozygous individuals of stent thrombosis, lower PON1 plasma activity, lower plasma concentrations of active metabolite and lower platelet inhibition. Thus, we identified PON1 as a key factor for the bioactivation and clinical activity of clopidogrel. These findings have therapeutic implications and may be exploited to prospectively assess the clinical efficacy of clopidogrel.

Flow regulates arterial-venous differentiation in the chick embryo yolk sac.

Abstract: Formation of the yolk sac vascular system and its connection to the embryonic circulation is crucial for embryo survival in both mammals and birds. Most mice with mutations in genes involved in vascular development die because of a failure to establish this circulatory loop. Surprisingly, formation of yolk sac arteries and veins has not been well described in the recent literature. Using time-lapse video-microscopy, we have studied arterial-venous differentiation in the yolk sac of chick embryos. Immediately after the onset of perfusion, the yolk sac exhibits a posterior arterial and an anterior venous pole, which are connected to each other by cis-cis endothelial interactions. To form the paired and interlaced arterial-venous pattern characteristic of mature yolk sac vessels, small caliber vessels of the arterial domain are selectively disconnected from the growing arterial tree and subsequently reconnected to the venous system, implying that endothelial plasticity is needed to fashion normal growth of veins. Arterial-venous differentiation and patterning are controlled by hemodynamic forces, as shown by flow manipulation and in situ hybridization with arterial markers ephrinB2 and neuropilin 1, which show that expression of both mRNAs is not genetically determined but plastic and regulated by flow. In vivo application of ephrinB2 or EphB4 in the developing yolk sac failed to produce any morphological effects. By contrast, ephrinB2 and EphB4 application in the allantois of older embryos resulted in the rapid formation of arterial-venous shunts. In conclusion, we show that flow shapes the global patterning of the arterial tree and regulates the activation of the arterial markers ephrinB2 and neuropilin 1.

Definitions of women's sexual dysfunction reconsidered: advocating expansion and revision.

Abstract: In light of various shortcomings of the traditional nosology of women's sexual disorders for both clinical practice and research, an international multi-disciplinary group has reviewed the evidence for traditional assumptions about women's sexual response. It is apparent that fullfillment of sexual desire is an uncommon reason/incentive for sexual activity for many women and, in fact, sexual desire is frequently experienced only after sexual stimuli have elicited subjective sexual arousal. The latter is often poorly correlated with genital vasocongestion. Complaints of lack of subjective arousal despite apparently normal genital vasocongestion are common. Based on the review of existing evidence-based research, many modifications to the definitions of women's sexual dysfunctions are recommended. There is a new definition of sexual interest/desire disorder, sexual arousal disorders are separated into genital and subjective subtypes and the recently recognized condition of persistent sexual arousal is included. The definition of dyspareunia reflects the possibility of the pain precluding intercourse. The anticipation and fear of pain characteristic of vaginismus is noted while the assumed muscular spasm is omitted given the lack of evidence. Finally, a recommendation is made that all diagnoses be accompanied by descriptors relating to associated contextual factors and to the degree of distress.