Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 178
Filter
1.
Neth Heart J ; 29(6): 301-308, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33528799

ABSTRACT

In relatives of index patients with dilated cardiomyopathy and arrhythmogenic cardiomyopathy, early detection of disease onset is essential to prevent sudden cardiac death and facilitate early treatment of heart failure. However, the optimal screening interval and combination of diagnostic techniques are unknown. The clinical course of disease in index patients and their relatives is variable due to incomplete and age-dependent penetrance. Several biomarkers, electrocardiographic and imaging (echocardiographic deformation imaging and cardiac magnetic resonance imaging) techniques are promising non-invasive methods for detection of subclinical cardiomyopathy. However, these techniques need optimisation and integration into clinical practice. Furthermore, determining the optimal interval and intensity of cascade screening may require a personalised approach. To address this, the CVON-eDETECT (early detection of disease in cardiomyopathy mutation carriers) consortium aims to integrate electronic health record data from long-term follow-up, diagnostic data sets, tissue and plasma samples in a multidisciplinary biobank environment to provide personalised risk stratification for heart failure and sudden cardiac death. Adequate risk stratification may lead to personalised screening, treatment and optimal timing of implantable cardioverter defibrillator implantation. In this article, we describe non-invasive diagnostic techniques used for detection of subclinical disease in relatives of index patients with dilated cardiomyopathy and arrhythmogenic cardiomyopathy.

2.
Article in English | MEDLINE | ID: mdl-29573030

ABSTRACT

AIM: Somatoform disorders are common and often chronic. It would be helpful to distinguish those patients who are likely to have a positive treatment course from those who are likely to follow a negative course. Such studies of different somatoform disorders are scarce, especially in secondary psychiatric care. This study examined the 6-month treatment course of psychological, physical symptoms, and functioning, and its predictors in a naturalistic sample of secondary psychiatric care outpatients with somatoform disorders. METHOD: The present study used routine outcome monitoring data of patients with somatoform disorders regarding their 6-month treatment course of psychological and physical symptoms as well as functioning. The following patient groups were included: total group of somatoform disorders (N = 435), and undifferentiated somatoform disorder (N = 242), pain disorder (N = 102), body dysmorphic disorder (N = 51), and hypochondriasis (N = 40). Measures were Mini-International Neuropsychiatric Interview plus, Brief Symptom Inventory, Montgomery-Ǻsberg Depression Rating Scale, Brief Anxiety Scale, Short Form Health Survey 36, and Physical Symptom Checklist (PSC). RESULTS: The study population generally showed high co-morbidity, especially with anxiety and mood disorders. The PSC total score, body dysmorphic disorder, and hypochondriasis were significant predictors for the treatment course of symptoms (Brief Symptom Inventory), whereas the PSC total score was the only significant predictor for the course of functioning (Short Form Health Survey 36). CONCLUSION: Secondary psychiatric care outpatients with somatoform disorders showed high co-morbidity with anxiety and mood disorders, and an unfavourable 6-month course of both symptoms and functioning. Clinical implications are discussed, such as additional treatment of co-morbidity in somatoform disorders.

3.
Neth Heart J ; 26(1): 3-4, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29196877

ABSTRACT

Gold open access provides free distribution of trustworthy scientific knowledge for everyone. As publication modus, it has to withstand the bad reputation of predatory journals and overcome the preconceptions of those who believe that open access is synonymous with poor quality articles and high costs. Gold open access has a bright future and will serve the scientific community, clinicians without academic affiliations and the general public.

4.
Neth Heart J ; 25(3): 157-169, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28102477

ABSTRACT

Arrhythmogenic cardiomyopathy, or its most well-known subform arrhythmogenic right ventricular cardiomyopathy (ARVC), is a cardiac disease mainly characterised by a gradual replacement of the myocardial mass by fibrous and fatty tissue, leading to dilatation of the ventricular wall, arrhythmias and progression towards heart failure. ARVC is commonly regarded as a disease of the intercalated disk in which mutations in desmosomal proteins are an important causative factor. Interestingly, the Dutch founder mutation PLN R14Del has been identified to play an additional, and major, role in ARVC patients within the Netherlands. This is remarkable since the phospholamban (PLN) protein plays a leading role in regulation of the sarcoplasmic reticulum calcium load rather than in the establishment of intercellular integrity. In this review we outline the intracellular cardiac calcium dynamics and relate pathophysiological signalling, induced by disturbed calcium handling, with activation of calmodulin dependent kinase II (CaMKII) and calcineurin A (CnA). We postulate a thus far unrecognised role for Ca2+ sensitive signalling proteins in maladaptive remodelling of the macromolecular protein complex that forms the intercalated disk, during pro-arrhythmic remodelling of the heart.

6.
Tijdschr Psychiatr ; 57(8): 579-87, 2015.
Article in Dutch | MEDLINE | ID: mdl-26402894

ABSTRACT

BACKGROUND: Evidence-based therapies for major depression, as described in the clinical guidelines, are based on results from randomised controlled trials (RCTs). So far, it is not known to what extent results of RCTs on major depression can be generalised to 'real life' clinical practice. AIM: To compare treatment results for major depression from RCTs (efficacy) and results from daily practice (effectiveness); furthermore, to assess to what extent eligibility criteria and (un)intended selection by recruitment procedures influences treatment outcomes in daily practice. METHOD: In a 'real life' patient population (n=1653) suffering from major depression (established by the MINIplus) and assessed in routine outcome monitoring at baseline, we explored how many patients met the eligibility criteria for antidepressant and psychotherapy efficacy trials. Furthermore we explored to what extent RCT participants differed in socio-demographic and socio-economic status from 'daily practice' patients. 626 of the ROM patients had at least one follow-up assessment. In this follow-up group we compared the treatment outcome (assessed by the MADRS and BDI-II) to the results of 15 meta-analyses of RCTs. We also explored to what extent patient selection based on eligibility criteria and socio-demographic/socio-economic status influenced treatment outcome. RESULTS: Remission percentages (21-27% in ROM versus 34-58% in RCTs) and effect sizes (0.85 in ROM versus 1.71 in RCTs, within-group data) were lower in daily practice than in RCTs. ROM patients differed from RCT participants in many disease-specific and socio-economic features. These differences are due to patient selection in RCTs. However, the influence of patient selection based on eligibility criteria and socio-demographic differences in treatment outcome were very modest (explained variances 1-11%). CONCLUSION: Treatment success for major depression is lower in daily practice than in RCTs and 'real life' patients differ in many features from RCT participants. However, these differences cannot explain the difference between efficacy and effectiveness. The generalisability of the results of depression trials to daily practice might not be jeopardised by the use of eligibility criteria and recruitment procedures to the extent suggested in earlier research.


Subject(s)
Ambulatory Care/statistics & numerical data , Antidepressive Agents/therapeutic use , Depressive Disorder, Major/therapy , Outcome Assessment, Health Care/statistics & numerical data , Psychotherapy/methods , Ambulatory Care/methods , Combined Modality Therapy , Evidence-Based Medicine , Humans , Outcome Assessment, Health Care/methods , Randomized Controlled Trials as Topic , Severity of Illness Index , Treatment Outcome
7.
Neth Heart J ; 22(5): 198-213, 2014 May.
Article in English | MEDLINE | ID: mdl-24733689

ABSTRACT

Sudden cardiac death due to ventricular arrhythmias is a major problem. Drug therapies to prevent SCD do not provide satisfying results, leading to the demand for new antiarrhythmic strategies. New targets include Ca(2+)/Calmodulin-dependent protein kinase II (CaMKII), the Na/Ca exchanger (NCX), the Ryanodine receptor (RyR, and its associated protein FKBP12.6 (Calstabin)) and the late component of the sodium current (I Na-Late ), all related to intracellular calcium (Ca(2+)) handling. In this review, drugs interfering with these targets (SEA-0400, K201, KN-93, W7, ranolazine, sophocarpine, and GS-967) are evaluated and their future as clinical compounds is considered. These new targets prove to be interesting; however more insight into long-term drug effects is necessary before clinical applicability becomes reality.

8.
Neth Heart J ; 22(7-8): 316-25, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24817548

ABSTRACT

Arrhythmogenic cardiomyopathy (AC), also known as arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), is a hereditary disease characterised by ventricular arrhythmias, right ventricular and/or left ventricular dysfunction, and fibrofatty replacement of cardiomyocytes. Patients with AC typically present between the second and the fourth decade of life with ventricular tachycardias. However, sudden cardiac death (SCD) may be the first manifestation, often at young age in the concealed stage of disease. AC is diagnosed by a set of clinically applicable criteria defined by an international Task Force. The current Task Force Criteria are the essential standard for a correct diagnosis in individuals suspected of AC. The genetic substrate for AC is predominantly identified in genes encoding desmosomal proteins. In a minority of patients a non-desmosomal mutation predisposes to the phenotype. Risk stratification in AC is imperfect at present. Genotype-phenotype correlation analysis may provide more insight into risk profiles of index patients and family members. In addition to symptomatic treatment, prevention of SCD is the most important therapeutic goal in AC. Therapeutic options in symptomatic patients include antiarrhythmic drugs, catheter ablation, and ICD implantation. Furthermore, patients with AC and also all pathogenic mutation carriers should be advised against practising competitive and endurance sports.

9.
Soc Psychiatry Psychiatr Epidemiol ; 48(6): 975-84, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23212828

ABSTRACT

PURPOSE: Sociodemographic and socioeconomic characteristics of participants in antidepressant and psychotherapy efficacy trials (AETs and PETs) for major depressive disorder (MDD) may limit the generalizability of the results. We compared trial participants with daily practice patients. We subsequently assessed the influence of socio-demographic and socioeconomic status on treatment outcome in daily practice. METHODS: Data on daily practice patients were derived through routine outcome monitoring (ROM). We included 626 patients with MDD according to the MINIplus. Distributions of age, gender, race, marital status and employment status were compared with participants in 63 selected AETs and PETs. Influence of these features on treatment outcome was explored through multivariate regression analysis. RESULTS: Trial participants were older, more often male (diff. 4 %, p = 0.05), white (diff. 4 %, p < 0.001) and not married (diff. 7 %, p = 0.003). Although significant, most differences were relatively small. However, the difference in employment status was striking: 34 % of the ROM patients were currently working versus 68 % of the trial participants (diff. 34 %, p < 0.001). Being employed contributed to a positive treatment outcome: OR 1.8 for response [50 % reduction of Montgomery Asberg Rating Scale for Depression (MADRS)], OR 1.9 for remission (MADRS ≤10). CONCLUSIONS: Employment status should be taken into account while interpreting results from randomized controlled trials and as predictor of treatment success in daily practice.


Subject(s)
Depressive Disorder, Major/therapy , Employment/psychology , Randomized Controlled Trials as Topic/methods , Social Class , Socioeconomic Factors , Adolescent , Adult , Antidepressive Agents/therapeutic use , Cognitive Behavioral Therapy , Community Mental Health Services/methods , Community Mental Health Services/statistics & numerical data , Employment/statistics & numerical data , Female , Humans , Male , Netherlands , Psychiatric Status Rating Scales , Treatment Outcome , Young Adult
10.
Mol Psychiatry ; 16(5): 516-32, 2011 May.
Article in English | MEDLINE | ID: mdl-20351714

ABSTRACT

Data from the Genetic Association Information Network (GAIN) genome-wide association study (GWAS) in major depressive disorder (MDD) were used to explore previously reported candidate gene and single-nucleotide polymorphism (SNP) associations in MDD. A systematic literature search of candidate genes associated with MDD in case-control studies was performed before the results of the GAIN MDD study became available. Measured and imputed candidate SNPs and genes were tested in the GAIN MDD study encompassing 1738 cases and 1802 controls. Imputation was used to increase the number of SNPs from the GWAS and to improve coverage of SNPs in the candidate genes selected. Tests were carried out for individual SNPs and the entire gene using different statistical approaches, with permutation analysis as the final arbiter. In all, 78 papers reporting on 57 genes were identified, from which 92 SNPs could be mapped. In the GAIN MDD study, two SNPs were associated with MDD: C5orf20 (rs12520799; P=0.038; odds ratio (OR) AT=1.10, 95% CI 0.95-1.29; OR TT=1.21, 95% confidence interval (CI) 1.01-1.47) and NPY (rs16139; P=0.034; OR C allele=0.73, 95% CI 0.55-0.97), constituting a direct replication of previously identified SNPs. At the gene level, TNF (rs76917; OR T=1.35, 95% CI 1.13-1.63; P=0.0034) was identified as the only gene for which the association with MDD remained significant after correction for multiple testing. For SLC6A2 (norepinephrine transporter (NET)) significantly more SNPs (19 out of 100; P=0.039) than expected were associated while accounting for the linkage disequilibrium (LD) structure. Thus, we found support for involvement in MDD for only four genes. However, given the number of candidate SNPs and genes that were tested, even these significant may well be false positives. The poor replication may point to publication bias and false-positive findings in previous candidate gene studies, and may also be related to heterogeneity of the MDD phenotype as well as contextual genetic or environmental factors.


Subject(s)
Depressive Disorder, Major/genetics , Genetic Predisposition to Disease , Polymorphism, Single Nucleotide/genetics , Computational Biology , Gene Frequency , Genome-Wide Association Study , Genotype , Humans , Linkage Disequilibrium , Nerve Tissue Proteins/genetics , Neuropeptide Y/genetics , Norepinephrine Plasma Membrane Transport Proteins/genetics , Odds Ratio , Peptidyl-Dipeptidase A/genetics , PubMed/statistics & numerical data , Tumor Necrosis Factor-alpha/genetics
11.
Ultrasound Obstet Gynecol ; 40(4): 406-11, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22173946

ABSTRACT

OBJECTIVE: To determine if decreased resistance (vasodilatation) in the maternal middle cerebral artery (MCA) in the second trimester can predict third-trimester development of pre-eclampsia. METHODS: Four-hundred and five low-risk gravidas had MCA transcranial Doppler (TCD) once in the second trimester. Maternal/neonatal outcomes were evaluated after delivery. Mean blood pressure, MCA velocities, resistance index (RI), pulsatility index (PI) and cerebral perfusion pressure (CPP) were compared between normotensive and pre-eclamptic cohorts. RESULTS: Seven subjects (1.7%) developed pre-eclampsia. An RI of < 0.54 and a PI of < 0.81 were clinically useful in predicting subsequent pre-eclampsia. Areas under the receiver-operating characteristics curves for RI and PI were 0.93 and 0.93, respectively, with optimal sensitivity and specificity of 86% and 93% for both variables. Positive and negative likelihood ratios were 11.8/0.15 (RI) and 12.3/0.15 (PI). CONCLUSION: TCD indices of low maternal MCA resistance in the second trimester are predictive of the subsequent development of pre-eclampsia in a low-risk, ethnically homogeneous population.


Subject(s)
Middle Cerebral Artery/physiopathology , Pre-Eclampsia/physiopathology , Pregnancy Trimester, Second , Ultrasonography, Doppler, Color , Vascular Resistance , Adult , Blood Flow Velocity , Blood Pressure , Female , Humans , Infant, Newborn , Middle Cerebral Artery/diagnostic imaging , Pre-Eclampsia/diagnostic imaging , Predictive Value of Tests , Pregnancy , Pregnancy Outcome , ROC Curve , Sensitivity and Specificity , Ultrasonography, Prenatal , Vasodilation
12.
Circulation ; 121(1): 123-31, 2010 Jan 05.
Article in English | MEDLINE | ID: mdl-20026782

ABSTRACT

BACKGROUND: Endothelial dysfunction is the initiating event of atherosclerosis. The expression of connexin40 (Cx40), an endothelial gap junction protein, is decreased during atherogenesis. In the present report, we sought to determine whether Cx40 contributes to the development of the disease. METHODS AND RESULTS: Mice with ubiquitous deletion of Cx40 are hypertensive, a risk factor for atherosclerosis. Consequently, we generated atherosclerosis-susceptible mice with endothelial-specific deletion of Cx40 (Cx40del mice). Cx40del mice were indeed not hypertensive. The progression of atherosclerosis was increased in Cx40del mice after 5 and 10 weeks of a high-cholesterol diet, and spontaneous lesions were observed in the aortic sinuses of young mice without such a diet. These lesions showed monocyte infiltration into the intima, increased expression of vascular cell adhesion molecule-1, and decreased expression of the ecto-enzyme CD73 in the endothelium. The proinflammatory phenotype of Cx40del mice was confirmed in another model of induced leukocyte recruitment from the lung microcirculation. Endothelial CD73 is known to induce antiadhesion signaling via the production of adenosine. We found that reducing Cx40 expression in vitro with small interfering RNA or antisense decreased CD73 expression and activity and increased leukocyte adhesion to mouse endothelial cells. These effects were reversed by an adenosine receptor agonist. CONCLUSIONS: Cx40-mediated gap junctional communication contributes to a quiescent nonactivated endothelium by propagating adenosine-evoked antiinflammatory signals between endothelial cells. Alteration in this mechanism by targeting Cx40 promotes leukocyte adhesion to the endothelium, thus accelerating atherosclerosis.


Subject(s)
5'-Nucleotidase/metabolism , Atherosclerosis/physiopathology , Connexins/genetics , Endothelial Cells/pathology , Vasculitis/physiopathology , Animals , Atherosclerosis/immunology , Atherosclerosis/pathology , Cell Adhesion/immunology , Cells, Cultured , Connexins/metabolism , Endothelial Cells/metabolism , Gap Junctions/metabolism , Green Fluorescent Proteins/genetics , Mice , Mice, Transgenic , Monocytes/metabolism , Monocytes/pathology , RNA, Small Interfering , Signal Transduction/immunology , Vasculitis/immunology , Vasculitis/pathology , Gap Junction alpha-5 Protein
13.
Psychol Med ; 41(7): 1353-63, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21078225

ABSTRACT

BACKGROUND: Generalizability of antidepressant efficacy trials (AETs) to daily practice is questioned because of their very stringent patient selection. This study aims to determine eligibility for AETs of out-patients suffering from major depression in a routine out-patient setting and investigates influence of eligibility on treatment outcome. METHOD: Data collection (n = 1653) was performed through routine outcome monitoring by independent trained research nurses. The Mini-International Neuropsychiatric Interview Plus and the Dimensional Assessment of Personality Pathology, short Dutch version were used for diagnostic assessment and personality pathology screening. The Montgomery-Asberg Depression Rating Scale (MADRS) was used for assessment of baseline severity and treatment outcome. Eligibility was assessed by stepwise application of commonly used exclusion criteria. Influence of eligibility on treatment outcome was investigated in a subsample of the 1653 patients who had at least one follow-up assessment (n = 626). Eligible and non-eligible patients were compared on proportion of response (50% reduction) and remission on MADRS (MADRS ≤ 10). RESULTS: Altogether, 17-25% of the patients were eligible for AETs. The most common reasons for exclusion would be 'not meeting minimum baseline severity' and 'presence of co-morbid Axis I disorder'. Eligible and non-eligible patients did not differ in treatment outcome. Only 'meeting the minimum baseline severity' is associated with remission. CONCLUSIONS: The majority of 'real life' out-patients are not eligible for AETs. However, the influence of eligibility on treatment outcome seems to be small. This suggests that stringent patient selection by eligibility criteria is not the major reason for lack of generalizability of AETs. Exclusion of less severely depressed patients from the analyses resulted in better treatment outcome. Milder depression is highly prevalent in daily practice and more research into treatment effectiveness in milder depression is warranted.


Subject(s)
Ambulatory Care/methods , Antidepressive Agents/therapeutic use , Depressive Disorder, Major/drug therapy , Outpatients/statistics & numerical data , Patient Selection , Research Design , Adult , Clinical Trials as Topic , Female , Humans , Male , Netherlands , Outpatients/psychology , Practice Patterns, Physicians' , Psychiatric Status Rating Scales/statistics & numerical data , Treatment Outcome
14.
Nat Commun ; 12(1): 7151, 2021 12 09.
Article in English | MEDLINE | ID: mdl-34887420

ABSTRACT

The heterozygous Phospholamban p.Arg14del mutation is found in patients with dilated or arrhythmogenic cardiomyopathy. This mutation triggers cardiac contractile dysfunction and arrhythmogenesis by affecting intracellular Ca2+ dynamics. Little is known about the physiological processes preceding induced cardiomyopathy, which is characterized by sub-epicardial accumulation of fibrofatty tissue, and a specific drug treatment is currently lacking. Here, we address these issues using a knock-in Phospholamban p.Arg14del zebrafish model. Hearts from adult zebrafish with this mutation display age-related remodeling with sub-epicardial inflammation and fibrosis. Echocardiography reveals contractile variations before overt structural changes occur, which correlates at the cellular level with action potential duration alternans. These functional alterations are preceded by diminished Ca2+ transient amplitudes in embryonic hearts as well as an increase in diastolic Ca2+ level, slower Ca2+ transient decay and longer Ca2+ transients in cells of adult hearts. We find that istaroxime treatment ameliorates the in vivo Ca2+ dysregulation, rescues the cellular action potential duration alternans, while it improves cardiac relaxation. Thus, we present insight into the pathophysiology of Phospholamban p.Arg14del cardiomyopathy.


Subject(s)
Calcium-Binding Proteins/genetics , Calcium/metabolism , Cardiomyopathy, Dilated/genetics , Etiocholanolone/analogs & derivatives , Zebrafish/metabolism , Animals , Calcium-Binding Proteins/metabolism , Cardiomyopathy, Dilated/metabolism , Cardiomyopathy, Dilated/physiopathology , Disease Models, Animal , Echocardiography , Etiocholanolone/administration & dosage , Female , Gene Knock-In Techniques , Humans , Male , Myocardial Contraction , Myocardium/metabolism , Sequence Deletion , Zebrafish/genetics
15.
Acta Psychiatr Scand ; 122(1): 30-9, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20456284

ABSTRACT

OBJECTIVE: The metabolic syndrome (MetSyn) predisposes to cardiovascular disease and diabetes mellitus. There might also be an association between the MetSyn and anxiety and depression, but its nature is unclear. We aimed to investigate whether diagnosis, symptom severity and antidepressant use are associated with the MetSyn. METHOD: We addressed the odds for the MetSyn and its components among 1217 depressed and/or anxious subjects and 629 controls, and their associations with symptom severity and antidepressant use. RESULTS: Symptom severity was positively associated with prevalence of the MetSyn, [adjusted odds ratio (OR) 2.21 for very severe depression: 95% confidence interval (CI): 1.06-4.64, P = 0.04], which could be attributed to abdominal obesity and dyslipidemia. Tricyclic antidepressant (TCA) use also increased odds for the MetSyn (OR 2.30, 95% CI: 1.21-4.36, P = 0.01), independent of depression severity. CONCLUSION: The most severely depressed people and TCA users more often have the MetSyn, which is driven by abdominal adiposity and dyslipidemia.


Subject(s)
Antidepressive Agents, Tricyclic/administration & dosage , Anxiety/epidemiology , Depression/epidemiology , Metabolic Syndrome/epidemiology , Severity of Illness Index , Adult , Antidepressive Agents, Tricyclic/adverse effects , Anxiety/drug therapy , Comorbidity , Coronary Artery Disease/epidemiology , Depression/diagnosis , Depression/drug therapy , Female , Humans , Hypertension/epidemiology , Male , Metabolic Syndrome/diagnosis , Middle Aged , Obesity, Abdominal/epidemiology , Prevalence
17.
Basic Res Cardiol ; 104(5): 511-22, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19255801

ABSTRACT

Cardiac sodium channels are responsible for conduction in the normal and diseased heart. We aimed to investigate regional and transmural distribution of sodium channel expression and function in the myocardium. Sodium channel Scn5a mRNA and Na(v)1.5 protein distribution was investigated in adult and embryonic mouse heart through immunohistochemistry and in situ hybridization. Functional sodium channel availability in subepicardial and subendocardial myocytes was assessed using patch-clamp technique. Adult and embryonic (ED14.5) mouse heart sections showed low expression of Na(v)1.5 in the HCN4-positive sinoatrial and atrioventricular nodes. In contrast, high expression levels of Na(v)1.5 were observed in the HCN4-positive and Cx43-negative AV or His bundle, bundle branches and Purkinje fibers. In both ventricles, a transmural gradient was observed, with a low Na(v)1.5 labeling intensity in the subepicardium as compared to the subendocardium. Similar Scn5a mRNA expression patterns were observed on in situ hybridization of embryonic and adult tissue. Maximal action potential upstroke velocity was significantly lower in subepicardial myocytes (mean +/- SEM 309 +/- 32 V/s; n = 14) compared to subendocardial myocytes (394 +/- 32 V/s; n = 11; P < 0.05), indicating decreased sodium channel availability in subepicardium compared to subendocardium. Scn5a and Na(v)1.5 show heterogeneous distribution patterns within the cardiac conduction system and across the ventricular wall. This differential distribution of the cardiac sodium channel may have profound consequences for conduction disease phenotypes and arrhythmogenesis in the setting of sodium channel disease.


Subject(s)
Heart Conduction System/metabolism , Muscle Proteins/metabolism , Myocardium/metabolism , Sodium Channels/metabolism , Action Potentials , Animals , Atrioventricular Node/metabolism , Bundle of His/metabolism , Cell Line , Gene Expression Regulation, Developmental , Heart Conduction System/embryology , Heart Ventricles/metabolism , Humans , Immunohistochemistry , In Situ Hybridization , Male , Mice , Muscle Proteins/genetics , NAV1.5 Voltage-Gated Sodium Channel , Patch-Clamp Techniques , Purkinje Fibers/metabolism , RNA, Messenger/metabolism , Recombinant Fusion Proteins/metabolism , Sodium Channels/genetics , Transfection
18.
Neuron ; 13(5): 1159-66, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7946352

ABSTRACT

The retina of the mouse, rabbit, and guinea pig is divided into a superior area dominated by green-sensitive (M) cones and an inferior area in which cones possess practically only short wavelength-sensitive (S) photopigments. The present study shows that the transitional zone between these retinal areas is populated by cones labeled by both the M and S cone photopigment-specific antibodies COS-1 and OS-2. It is concluded that the overwhelming majority of the transitional cones express both visual pigments. A small population of the transitional cones was strongly labeled exclusively by OS-2 (genuine S cones). The results indicate that, in contrast to the generally accepted idea of one visual pigment per one cone cell, cones of certain mammalian species can express different opsins simultaneously under natural conditions. We speculate that the coexpression may be due to the overlapping of regulatory factors determining the M and S fields.


Subject(s)
Retinal Cone Photoreceptor Cells/chemistry , Retinal Pigments/metabolism , Animals , Antibodies, Monoclonal , Guinea Pigs , Immunologic Techniques , Mice , Rabbits , Retinal Cone Photoreceptor Cells/metabolism
19.
Neth Heart J ; 16(10): 356-8, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18958260

ABSTRACT

Mutations that are supposed to affect right (RV) and left ventricular (LV) electrophysiology equally, often reveal dominant conduction slowing and arrhythmia vulnerability in RV. In this study we investigated the mechanism of dominant arrhythmia vulnerability of RV in senescent mice. We performed epicardial ventricular activation mapping on adult and senescent Langendorff perfused hearts. Longitudinal and transversal conduction velocity, as well as arrhythmia inducibility were determined. Subsequently, hearts were processed for immunohisto-chemistry and Picro Sirius Red staining. Senescent mice revealed decreased conduction velocity, increased aniso-tropic ratio and reduced excitation wavelength in RV, but not in LV. Arrhythmias were mainly induced in RV of senescent hearts. No arrhythmias were induced in adult hearts. Immunohistochemistry revealed that the amount of Connexin 43 and cardiac sodium channel Nav1 .5 were equally decreased, and that collagen content was equally increased in senescent RV and LV. However, patches of replacement fibrosis were found throughout the RV wall, but only in the sub-endocardium and mid-myocardium of LV. The study shows that the dominant arrhythmia vulnerability in RV of senescent mice is caused by the distribution of replacement fibrosis which involves the entire RV but only part of the LV. (Neth Heart J 2008;16:356-8.).

20.
Neth Heart J ; 16(3): 106-9, 2008.
Article in English | MEDLINE | ID: mdl-18345333

ABSTRACT

During cardiac maturation, increased exposure of the heart to circulating catecholamines correlates with increased conduction velocity and growth of the heart. We used an in vitro approach to study the underlying mechanisms of adrenergic stimulation induced changes in conduction velocity. By combining functional measurements and molecular techniques, we were able to demonstrate that the increased conduction velocity after beta-adrenergic stimulation is probably not caused by changes in intercellular coupling. Instead, RT-PCR experiments and action potential measurements have shown an increased excitability that may well explain the observed increase in conduction velocity. Apart from being relevant to cardiac maturation, our findings are relevant in the context of stem cells and cardiac repair. Preconditioning of stem cell derived cardiomyocytes may help to enhance electrical maturation of de novo generated cardiomyocytes and consequently reduce their proarrhythmogenic potential. (Neth Heart J 2008;16:106-9.).

SELECTION OF CITATIONS
SEARCH DETAIL