Publications by authors named "Gaalen M"

The adoption of digital measures in pharmaceutical research and development (R&D) presents an opportunity to enhance the efficiency and effectiveness of discovering and developing new therapeutics. For clinical measures, the Digital Medicine Society's (DiMe) V3 Framework is a comprehensive validation framework that encompasses verification, analytical validation, and clinical validation. This manuscript describes collaborative efforts to adapt this framework to ensure the reliability and relevance of digital measures for a preclinical context.

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Background And Aims: The effectiveness of transition programs from paediatric to adult healthcare in adolescents with inflammatory bowel disease is not clear, as prospective studies using validated outcome measures for transition are lacking. This study aimed to develop and validate a quantitative Transition Success Score, and to apply it in a multicenter setting to assess the effectiveness of transitional care.

Methods: The Top 10 outcome items related to successful transition, identified through an international Delphi study with IBD stakeholders, were integrated into a generic questionnaire, the Transition Success Score.

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Background: In patients with chest pain who arrive at the emergency department (ED) by ambulance, venous access is frequently established prehospital, and could be utilized to sample blood. Prehospital blood sampling may save time in the diagnostic process. In this study, the association of prehospital blood draw with blood sample arrival times, troponin turnaround times, and ED length of stay (LOS), number of blood sample mix-ups and blood sample quality were assessed.

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Objectives: Transition readiness can predict a successful transition from pediatric to adult care. This study aimed to validate and develop age-dependent reference scores for the (Dutch version of) Transition Readiness Assessment Questionnaire (TRAQ), in adolescents and young adults (AYAs) with inflammatory bowel disease (IBD).

Methods: TRAQ has 20 items (score 1-5) distributed over 5 domains (total sum score 100) and is completed by AYAs.

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We evaluated the diagnostic performance of 4 commercially NAAT for detecting SARS-CoV-2 RNA, Influenza type A/B virus and RSV. Included tests were the Allplex™ SARS-CoV-2 fast PCR Assay (RNA extraction-free), Allplex™ RV Master Assay, Allplex™ SARS-CoV-2 fast MDx Assay (LAMP) and Aptima™ SARS-CoV-2/Flu Assay (RT-TMA). The assays' performance characteristics were determined using nasopharyngeal swabs from 270 patients with suspected SARS-CoV-2 infection.

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Disappointments in translating preclinical findings into clinical efficacy have triggered a number of changes in neuroscience drug discovery ranging from investments diverted to other therapeutic areas to reduced reliance on efficacy claims derived from preclinical models. In this chapter, we argue that there are several existing examples that teach us on what needs to be done to improve the success rate. We advocate the reverse engineering approach that shifts the focus from preclinical efforts to "model" human disease states to pharmacodynamic activity as a common denominator in the journey to translate clinically validated phenomena to preclinical level and then back to humans.

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Gene therapy in its current design is an irreversible process. It cannot be stopped in case of unwanted side effects, nor can expression levels of therapeutics be adjusted to individual patient's needs. Thus, the Gene-Switch (GS) system for pharmacologically regulable neurotrophic factor expression was established for treatment of parkinsonian patients.

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Objectives: Disease knowledge is important in adolescents with inflammatory bowel disease (IBD) transitioning to adult care. We developed an IBD-specific knowledge questionnaire, the Rotterdam Transition Test (RTT), and aimed to validate this tool.

Methods: This is a prospective longitudinal validation study.

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Introduction: In Sierra Leone, access to prostheses is limited due to absence of practical knowledge, materials, trained staff, and high cost. This paper investigates the impact of a 3D printed prosthesis on the health-related quality of life (HRQoL) in prosthesis recipients.

Methods: Patients with upper extremity amputations were included in this case study from December 2018 until July 2019.

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We report the case of a man with a transhumeral amputation in a rural area of Sierra Leone. The patient had fractured his humerus during a football match. Due to lack of transportation and medical centres nearby, the patient was seen by a traditional healer.

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Background: Challenges specific to the discovery and development of candidate CNS drugs have led to implementation of various in silico, in vitro and in vivo approaches to improve the odds for commercialization of novel treatments.

New Method: Advances in analytical methodology and microdialysis probe design have enabled development of a non-human primate model capable of measuring concentrations of drugs or endogenous chemicals in brain extracellular fluid (ECF) and cerebrospinal fluid (CSF). Linking these to population modeling reduces animal numbers to support predictive translational sciences in primates.

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Background: Transition programmes are designed to prepare adolescent inflammatory bowel disease [IBD] patients for transfer to adult care. It is still unclear which outcome parameters define 'successful transition'. Therefore, this study aimed to identify outcomes important for success of transition in IBD.

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Acute central nervous system exposure to dextroamphetamine (d-amphetamine) elicits a multitude of effects, including dual action on the dopamine transporter (DAT) to increase extracellular dopamine, and induction of a negative feedback response to limit the dopamine increase. A semimechanistic pharmacokinetic and pharmacodynamic (PK/PD) model with consideration of these multiple effects as a basis was developed. Integrated pharmacokinetics of d-amphetamine in plasma, brain extracellular fluid (ECF) via microdialysis, and cerebrospinal fluid were characterized using a population approach.

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Herein we report the discovery of a novel oxindole-based series of vasopressin 1b (V1b) receptor antagonists. Introducing a substituted piperazine moiety and optimizing the southern and the northern aromatic rings resulted in potent, selective and brain penetrant V1b receptor antagonists. Compound 9c was found to be efficacious in a rat model of anti-depressant activity (3 mg/kg, ip).

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Aim: It can be difficult for adolescents with inflammatory bowel disease (IBD) to make the transition from paediatric to adult care. We studied the outcomes of this process and defined what constituted a successful transition.

Methods: In 2008, 50 adolescents who attended our IBD transition clinic completed IBD-yourself, a self-efficacy questionnaire that we had previously developed and validated.

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The transfer of adolescent patients with inflammatory bowel disease (IBD) to adult gastroenterology services is often troublesome. Failed transition can have adverse effects on the course of disease. We present two cases of adolescent IBD patients and their transition process.

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Rats emit high-frequency 50-kHz ultrasonic vocalizations (USV) in appetitive situations like social interactions. Drugs of abuse are probably the most potent non-social elicitors of 50-kHz USV, possibly reflecting their euphorigenic properties. Psychostimulants induce the strongest elevation in 50-kHz USV emission, particularly amphetamine (AMPH), either when applied systemically or locally into the nucleus accumbens (Nacc).

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Serotonin (5-hydroxytryptamine, 5-HT) is an important modulatory neurotransmitter and functions as a key neurodevelopmental signal in the mammalian brain. 5-HT plays a prominent role in regulating various types of psychological processes and functions, including mood and emotion, particularly anxiety, but also in regulating social behavior. Consequently, the 5-HT system is implicated in various neuropsychiatric disorders, such as anxiety disorders and depression or autism spectrum disorders (ASD), with selective 5-HT reuptake inhibitors being the frontline medication.

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Stress-induced activation of the hypothalamo-pituitary-adrenocortical (HPA) axis and high circulating glucocorticoid levels are well known to impair the retrieval of memory. Vasopressin can activate the HPA axis by stimulating vasopressin 1b (V1b) receptors located on the pituitary. In the present study, we investigated the effect of A-988315, a selective and highly potent non-peptidergic V1b-receptor antagonist with good pharmacokinetic properties, in blocking stress effects on HPA-axis activity and memory retrieval.

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Rationale: Rats emit various distinct types of ultrasonic vocalizations (USV), with high-frequency 50-kHz USV typically occurring in appetitive situations being elicited by administering drugs of abuse, most notably amphetamine (AMPH), possibly reflecting drug wanting/craving and/or liking.

Objectives: Because 50-kHz USV emission is, at least in part, dopamine (DA) dependent and 5-HT2C agonists inhibit DA neurotransmission, we hypothesized that AMPH-induced 50-kHz USV can be attenuated by pretreatment with a 5-HT2C agonist.

Methods: In experiments I and II, a dose-response curve for AMPH-induced 50-kHz USV was established, and the partial dependency of AMPH-induced 50-kHz USV on DA neurotransmission was validated by pretreatment with the D2-antagonist eticlopride.

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The Nogo-66 receptor (NgR1) is part of a co-receptor complex on neurons that transmits a signal for inhibition of neurite outgrowth. In addition, NgR1 function has also been related to other disorders such as schizophrenia and Alzheimer's disease. Here, we studied the effect of life-long deletion of NgR1 (ngr(-/-)) in tests for cognition and positive symptoms of schizophrenia.

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Rationale: The clinical efficacy of the monoamine and noradrenaline transporter inhibitors methylphenidate and atomoxetine in attention deficit/hyperactivity disorder implicates noradrenergic neurotransmission in modulating inhibitory response control processes. Nonetheless, it is unclear which adrenoceptor subtypes are involved in these effects.

Objectives: The present study aimed at investigating the effects of adrenoceptor agonists on inhibitory response control as assessed in the rodent 5-choice serial reaction time task, a widely used translational model to measure this executive cognitive function.

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Herein we report the discovery of a novel series of vasopressin 1b (V1b) receptor antagonists, starting from potent but metabolically labile oxindole SSR149415. Masking the proline N,N-dimethyl amide moiety as an oxazole and attaching a benzylic amine moiety to the northern phenyl ring resulted in potent and selective V1b receptor antagonists with improved metabolic stability and improved pharmacokinetic properties in rat. Compound 18c was found to be efficacious in a rat model of anti-depressant activity.

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One major hallmark of Alzheimer's disease (AD) is the massive loss of synapses that occurs at an early clinical stage of the disease. In this study, we characterize alterations in spine density and the expression of synapse-associated immediate early gene Arc (activity-regulated cytoskeleton-associated protein) in the hippocampal CA1 regions of two different amyloid precursor protein (APP) transgenic mouse lines before plaque development and their connection to performance in hippocampus-dependent memory tests. The density of mushroom-type spines was reduced by 34% in the basal dendrites proximal to the soma of CA1 pyramidal neurons in 5.

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Antidepressant drug treatment is the clinical standard of care for all types of anxiety disorders. Broad efficacy of selective serotonin reuptake inhibitors suggests the importance of enhanced serotonergic function of the anxiolytic properties of current antidepressants. However, analysis of the preclinical evidence indicates that most conventional "anxiolytic" drug tests are not sensitive to antidepressants.

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