Close the Gap : a study on the regulation of Connexin43 gap junctional communication

Gap junctions are groups of transmembrane channels that connect the cytoplasms of adjacent cells to mediate the diffusion of small molecules, such as ions, metabolites, second messengers and small peptides. The building blocks of gap junctions are connexin proteins. The most ubiquitous and best studied connexin is connexin43 (Cx43). Cx43 is also known as the heart connexin. In the heart, gap junctional communication between cardiomyocytes ensures efficient electrical coupling and hence the synchronous propagation of action potentials. Misregulation of Cx43 expression, localisation and channel gating may lead to severe cardiac dysfunction. Cx43-based cell-cell coupling is rapidly disrupted following stimulation of certain G protein-coupled receptors (GPCRs). The studies presented in this thesis focus on the quest to unravel the signalling pathways leading to the transient inhibition of Cx43-based communication by GPCR activation. Our results suggest a model in which GPCR agonists inhibit Cx43-based gap junctional communication in two phases. Initial closure of the Cx43 channels si mediated by depletion of the phospholipid PIP2 from the plasma membrane, followed by internalisation of the gap junctions due to ubiquitination of Cx43 by the ubiquitin ligase Nedd4. New insights into the mechanisms underlying Cx43 gap junction closure may lead to new treatments of heart failure.KWF CBGUBL - phd migration 201

THE EFFECT OF LABELING INTENSITY, ESTIMATED BY REAL-TIME CONFOCAL LASER SCANNING MICROSCOPY, ON FLOW CYTOMETRIC APPEARANCE AND IDENTIFICATION OF IMMUNOCHEMICALLY LABELED MARINE DINOFLAGELLATES

Two different fluorescein isothiocyanate (FITC) conjugates were used to analyze the effect of labeling intensity on the flow cytometric appearance of marine dinoflagellates labeled with antibodies that specifically recognized the outer cell wall. Location of the labeling was revealed by epifluorescence and real-time confocal laser scanning microscopy using an anti-rabbit IgG/FITC-conjugated secondary antiserum. Flow cytometric measurements showed that cells of Prorocentrum species labeled this way could not always be distinguished from unlabeled cells. The labeling intensity increased several times when a biotinylated anti-rabbit IgG secondary antiserum was used in combination with a streptavidin/FITC conjugate. Flow cytometry indicated that the labeling intensity had increased 50%, which resulted in an improved separation of clusters of labeled and unlabeled cells.</p

Characterising the gut microbiome of stranded harbour seals (Phoca vitulina) in rehabilitation

Animal rehabilitation centres provide a unique opportunity to study the microbiome of wild animals because subjects will be handled for their treatment and can therefore be sampled longitudinally. However, rehabilitation may have unintended consequences on the animals' microbiome because of a less varied and suboptimal diet, possible medical treatment and exposure to a different environment and human handlers. Our study describes the gut microbiome of two large seal cohorts, 50 pups (0-30 days old at arrival) and 23 weaners (more than 60 days old at arrival) of stranded harbour seals admitted for rehabilitation at the Sealcentre Pieterburen in the Netherlands, and the effect of rehabilitation on it. Faecal samples were collected from all seals at arrival, two times during rehabilitation and before release. Only seals that did not receive antimicrobial treatment were included in the study. The average time in rehabilitation was 95 days for the pups and 63 days for the weaners. We observed that during rehabilitation, there was an increase in the relative abundance of some of the Campylobacterota spp and Actinobacteriota spp. The alpha diversity of the pups' microbiome increased significantly during their rehabilitation (p-value &lt;0.05), while there were no significant changes in alpha diversity over time for weaners. We hypothesize that aging is the main reason for the observed changes in the pups' microbiome. At release, the sex of a seal pup was significantly associated with the microbiome's alpha (i.e., Shannon diversity was higher for male pups, p-value &lt;0.001) and beta diversity (p-value 0.001). For weaners, variation in the microbiome composition (beta diversity) at release was partly explained by sex and age of the seal (p-values 0.002 and 0.003 respectively). We mainly observed variables known to change the gut microbiome composition (e.g., age and sex) and conclude that rehabilitation in itself had only minor effects on the gut microbiome of seal pups and seal weaners.</p

Characterising the gut microbiome of stranded harbour seals (Phoca vitulina) in rehabilitation

Animal rehabilitation centres provide a unique opportunity to study the microbiome of wild animals because subjects will be handled for their treatment and can therefore be sampled longitudinally. However, rehabilitation may have unintended consequences on the animals' microbiome because of a less varied and suboptimal diet, possible medical treatment and exposure to a different environment and human handlers. Our study describes the gut microbiome of two large seal cohorts, 50 pups (0-30 days old at arrival) and 23 weaners (more than 60 days old at arrival) of stranded harbour seals admitted for rehabilitation at the Sealcentre Pieterburen in the Netherlands, and the effect of rehabilitation on it. Faecal samples were collected from all seals at arrival, two times during rehabilitation and before release. Only seals that did not receive antimicrobial treatment were included in the study. The average time in rehabilitation was 95 days for the pups and 63 days for the weaners. We observed that during rehabilitation, there was an increase in the relative abundance of some of the Campylobacterota spp and Actinobacteriota spp. The alpha diversity of the pups' microbiome increased significantly during their rehabilitation (p-value &lt;0.05), while there were no significant changes in alpha diversity over time for weaners. We hypothesize that aging is the main reason for the observed changes in the pups' microbiome. At release, the sex of a seal pup was significantly associated with the microbiome's alpha (i.e., Shannon diversity was higher for male pups, p-value &lt;0.001) and beta diversity (p-value 0.001). For weaners, variation in the microbiome composition (beta diversity) at release was partly explained by sex and age of the seal (p-values 0.002 and 0.003 respectively). We mainly observed variables known to change the gut microbiome composition (e.g., age and sex) and conclude that rehabilitation in itself had only minor effects on the gut microbiome of seal pups and seal weaners.</p

Early diagnosis and follow-up of acute schistosomiasis in a cluster of infected Belgian travellers by detection of antibodies and circulating anodic antigen (CAA): a diagnostic evaluation study

Background: In order to evaluate the diagnostic value of schistosome circulating anodic antigen (CAA) detection, serum and urine CAA-levels were determined in a single cluster of 34 Belgian tourists at three timepoints within a period of 14 weeks following proven Schistosoma exposure in South Africa and compared with two in-house antibody assays. Methods: Samples were collected 4-5 and 7-8 weeks post-exposure and subsequently 5-6 weeks following praziquantel treatment. Schistosoma antibodies were detected by an adult worm antigen-immunofluorescence assay (AWA-IFA) and a soluble egg antigen-enzyme-linked immunosorbent assay (SEA-ELISA), while CAA concentrations were determined by the Up-Converting reporter Particle labelled Lateral Flow (UCP-LF) test. Results: Antibodies were detected in 25/34 (73%) travellers pre-treatment and in 27/34 (79%) post-treatment, with the AWA-IFA showing better performance than the SEA-ELISA. Pre-treatment, CAA was detected in 13/ 34 (38%) and 33/34 (97%) of the travellers in urine and serum, respectively. Post-treatment, all except one traveller became serum CAA negative. This in contrast to the detected antibodies, as well as the previously reported diagnostic results of this cluster. Conclusions: The UCP-LF CAA serum assay has been demonstrated as the most sensitive method for the diagnosis of early Schistosoma infections and post-treatment monitoring in travellers.Medical Microbiolog

Early parenting intervention: Family risk and first-time parenting related to intervention effectiveness

The effects of cumulative risk and parity on the effectiveness of a home based parenting intervention were tested in a randomized controlled trial with 237 families with 1- to 3-year-old children screened for high levels of externalizing behavior. The intervention was aimed at enhancing positive parenting and decreasing externalizing behaviors. The results showed that cumulative risk was not associated with either change in child externalizing behaviors or change in positive parenting. When intervention effectiveness was compared for primiparas (i.e., first-time mothers) versus multiparas (i.e., mothers with more than one child), we found that intervention mothers of first-born children displayed an increase in their use of positive discipline strategies as compared to first-time mothers in the control group, whereas a similar effect for multiparas was absent. Among multiparas we found an intervention effect on sensitivity, with control group mothers showing an increase in sensitivity, whereas the intervention group showed a constant level of sensitivity over time. These results suggest that parity may be a moderator of intervention effectiveness. Implications for investigating moderators of intervention effectiveness are discussed. © 2007 Springer Science+Business Media, LLC

Survival outcomes of patients with advanced mucosal melanoma diagnosed from 2013 to 2017 in the Netherlands - A nationwide population-based study

Background: Mucosal melanoma (MM) is rare and has a poor prognosis. Since 2011, new effective treatments are available for advanced melanoma. It is unclear whether patients with mucosal melanoma equally benefit from these new treatments compared with patients with cutaneous melanoma (CM). Methods: Patients with advanced MM and CM diagnosed between 2013 and 2017 were included from a nationwide population-based registry – the Dutch Melanoma Treatment Registry. Overall survival (OS) was estimated with the Kaplan-Meier method (also for a propensity score-matched cohort). A Cox model was used to analyse the association of possible prognostic factors with OS. Results: In total, 120 patients with MM and 2960 patients with CM were included. Median OS was 8.7 months and 14.5 months, respectively. Patients with MM were older (median age 70 versus 65 years) and more often female (60% versus 41%), compared with CM. In total, 77% and 2% of the MM patients were treated with first-line immunotherapy and targeted therapy, respectively, compared with 49% and 33% of the CM patients. In contrast to CM, OS for MM did not improve for patients diagnosed in 2015–2017, compared with 2013–2014. ECOG performance score ≥1 (HR = 1.99 [1.26–3.15; p = 0.003]) and elevated LDH level (HR = 1.63 [0.96–2.76]; p = 0.069) in MM were associated with worse survival. Conclusions: Within the era of immune and targeted therapies, prognosis for patients with advanced MM has not improved as much as for CM. Collaboration is necessary to enlarge sample size for research to improve immunotherapeutic strategies and identify targetable mutations

Predicting growth curves of early childhood externalizing problems: Differential susceptibility of children with difficult temperament

Using an accelerated longitudinal design, the development of externalizing problems from age 2 to 5 years was investigated in relation to maternal psychopathology, maternal parenting, gender, child temperament, and the presence of siblings. The sample consisted of 150 children selected at age 2-3 years for having high levels of externalizing problems. Parenting was measured using observational methods, and maternal reports were used for the other variables. Overall, mean levels of externalizing problems decreased over time, and higher initial levels (intercept) were related to a stronger decrease (negative slope) in externalizing problems. Results showed that higher levels of maternal psychopathology were related to less decrease in early childhood externalizing problems. Parental sensitive behavior predicted a stronger decrease in externalizing problems, but only for children with difficult temperaments. A stronger decrease of externalizing problems in children with older siblings also pertained only to children with difficult temperaments. Thus, temperamentally difficult children appear to be more susceptible to environmental influences on the development of externalizing behaviors. Our results indicate that the role of siblings in early childhood externalizing problems deserves more research attention, and that intervention efforts need to take into account temperamental differences in children's susceptibility to environmental influences. © 2009 Springer Science+Business Media, LLC

PRegnancy Outcomes after a Maternity Intervention for Stressful EmotionS (PROMISES): study protocol for a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>There is ample evidence from observational prospective studies that maternal depression or anxiety during pregnancy is a risk factor for adverse psychosocial outcomes in the offspring. However, to date no previous study has demonstrated that treatment of depressive or anxious symptoms in pregnancy actually could prevent psychosocial problems in children. Preventing psychosocial problems in children will eventually bring down the huge public health burden of mental disease. The main objective of this study is to assess the effects of cognitive behavioural therapy in pregnant women with symptoms of anxiety or depression on the child's development as well as behavioural and emotional problems. In addition, we aim to study its effects on the child's development, maternal mental health, and neonatal outcomes, as well as the cost-effectiveness of cognitive behavioural therapy relative to usual care.</p> <p>Methods/design</p> <p>We will include 300 women with at least moderate levels of anxiety or depression at the end of the first trimester of pregnancy. By including 300 women we will be able to demonstrate effect sizes of 0.35 or over on the total problems scale of the child behavioural checklist 1.5-5 with alpha 5% and power (1-beta) 80%.</p> <p>Women in the intervention arm are offered 10-14 individual cognitive behavioural therapy sessions, 6-10 sessions during pregnancy and 4-8 sessions after delivery (once a week). Women in the control group receive care as usual.</p> <p>Primary outcome is behavioural/emotional problems at 1.5 years of age as assessed by the total problems scale of the child behaviour checklist 1.5 - 5 years.</p> <p>Secondary outcomes will be mental, psychomotor and behavioural development of the child at age 18 months according to the Bayley scales, maternal anxiety and depression during pregnancy and postpartum, and neonatal outcomes such as birth weight, gestational age and Apgar score, health care consumption and general health status (economic evaluation).</p> <p>Trial Registration</p> <p>Netherlands Trial Register (NTR): <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2242">NTR2242</a></p