Sublaminar organization of the human subplate: developmental changes in the distribution of neurons,glia, growing axons and extracellular matrix

The objective of this paper was to collect normative data essential for analyzing the subplate (SP) role in pathogenesis of developmental disorders, characterized by abnormal circuitry, such as hypoxic‐ischemic lesions, autism and schizophrenia. The main cytological features of the SP, such as low cell density, early differentiation of neurons and glia, plexiform arrangement of axons and dendrites, presence of synapses and a large amount of extracellular matrix (ECM) distinguish this compartment from the cell‐dense cortical plate (CP; towards pia) and large fiber bundles of external axonal strata of fetal white matter (towards ventricle). For SP delineation from these adjacent layers based on combined cytological criteria, we analyzed the sublaminar distribution of different microstructural elements and the associated maturational gradients throughout development, using immunocytochemical and histological techniques on postmortem brain material (Zagreb Neuroembryological Collection). The analysis revealed that the SP compartment of the lateral neocortex shows changes in laminar organization throughout fetal development: the monolayer in the early fetal period (presubplate) undergoes dramatic bilaminar transformation between 13 and 15 postconceptional weeks (PCW), followed by subtle sublamination in three ‘floors’ (deep, intermediate, superficial) of midgestation (15–21 PCW). During the stationary phase (22–28 PCW), SP persists as a trilaminar compartment, gradually losing its sublaminar organization towards the end of gestation and remains as a single layer of SP remnant in the newborn brain. Based on these sublaminar transformations, we have documented developmental changes in the distribution, maturational gradients and expression of molecular markers in SP synapses, transitional forms of astroglia, neurons and ECM, which occur concomitantly with the ingrowth of thalamo‐cortical, basal forebrain and cortico‐cortical axons in a deep to superficial fashion. The deep SP is the zone of ingrowing axons – ‘entrance (ingrowth) zone’. The process of axonal ingrowth begins with thalamo‐cortical fibers and basal forebrain afferents, indicating an oblique geometry. During the later fetal period, deep SP receives long cortico‐cortical axons exhibiting a tangential geometry. Intermediate SP (‘proper’) is the navigation and ‘nexus’ sublamina consisting of a plexiform arrangement of cellular elements providing guidance and substrate for axonal growth, and also containing transient connectivity of dendrites and axons in a tangential plane without radial boundaries immersed in an ECM‐rich continuum. Superficial SP is the axonal accumulation (‘waiting compartment’) and target selection zone, indicating a dense distribution of synaptic markers, accumulation of thalamo‐cortical axons (around 20 PCW), overlapping with dendrites from layer VI neurons. In the late preterm brain period, superficial SP contains a chondroitin sulfate non‐immunoreactive band. The developmental dynamics for the distribution of neuronal, glial and ECM markers comply with sequential ingrowth of afferents in three levels of SP: ECM and synaptic markers shift from deep to superficial SP, with transient forms of glia following this arrangement, and calretinin neurons are concentrated in the SP during the formation phase. These results indicate developmental and morphogenetic roles in the SP cellular (transient glia, neurons and synapses) and ECM framework, enabling the spatial accommodation, navigation and establishment of numerous connections of cortical pathways in the expanded human brain. The original findings of early developmental dynamics of transitional subtypes of astroglia, calretinin neurons, ECM and synaptic markers presented in the SP are interesting in the light of recent concepts concerning its functional and morphogenetic role and an increasing interest in SP as a prospective substrate of abnormalities in cortical circuitry, leading to a cognitive deficit in different neurodevelopmental disorders.     

Social participation in early and established rheumatoid arthritis patients

Purpose: The aim of the study was to examine whether rheumatoid arthritis (RA) patients with different levels of restriction in social participation differ in disease related as well as psychosocial variables and whether a similar pattern can be found among early and established RA patients.

Method: Two samples of RA patients with early (n?=?97; age?=?53?±?12.3 years; disease duration?= 2.8?±?1.2 years; 76% women) and established (n?=?143; age?=?58?±?10.3 years; disease duration?= 16.1?±?3.6 years; 86% women) were collected. The pattern of differences for the patients with different level of participation restriction (no restriction, mild, moderate or high restriction) was explored by the Jonckheere–Terpstra test. Results: Significant differences were found between patients with different levels of social participation restrictions in both samples in pain, fatigue, functional disability, anxiety, depression and mastery. Generally, it was found that patients with higher restrictions experienced more pain and fatigue, more anxiety and depression and reported lower mastery. Similar pattern of differences concerning disease activity and self-esteem was found mainly in the established group. Conclusions: The study shows that the level of perceived restrictions in social participation are highly relevant regarding the disease related variables such as pain, fatigue and functional disability as well as psychological status and personal resources in both early and established RA.

• Implications for Rehabilitation

• Supporting involvement and participation of individuals with rheumatoid arthritis is important for decreasing the impact of RA symptoms on everyday life.

• Recognition and empowerment of individual resources such a mastery and self-esteem of RA patients could be beneficial for overcoming restrictions in participation.

     

A missense mutation in the 3-ketodihydrosphingosine reductase FVT1 as candidate causal mutation for bovine spinal muscular atrophy

The bovine form of the autosomal recessive neurodegenerative disease spinal muscular atrophy (SMA) shows striking similarity to the human form of the disease. It has, however, been mapped to a genomic region not harboring the bovine orthologue of the SMN gene, mutation of which causes human SMA. After refinement of the mapping results we analyzed positional and functional candidate genes. One of three candidate genes, FVT1, encoding 3-ketodihydrosphingosine reductase, which catalyzes a crucial step in the glycosphingolipid metabolism, showed a G-to-A missense mutation that changes Ala-175 to Thr. The identified mutation is limited to SMA-affected animals and carriers and always appears in context of the founder haplotype. The Ala variant found in healthy animals showed the expected 3-ketodihydrosphingosine reductase activity in an in vitro enzyme assay. Importantly, the Thr variant found in SMA animals showed no detectable activity. Surprisingly, in an in vivo assay the mutated gene complements the growth defect of a homologous yeast knockout strain as well as the healthy variant. This finding explains the viability of affected newborn calves and the later neuron-specific onset of the disease, which might be due to the high sensitivity of these neurons to changes in housekeeping functions. Taken together, the described mutation in FVT1 is a strong candidate for causality of SMA in cattle. This result provides an animal model for understanding the underlying mechanisms of the development of SMA and will allow efficient selection against the disease in cattle.     

Role of positron emission tomography and bone scintigraphy in the evaluation of bone involvement in metastatic pheochromocytoma and paraganglioma: specific implications for succinate dehydrogenase enzyme subunit B gene mutations

We performed a retrospective analysis of 71 subjects with metastatic pheochromocytoma and paraganglioma (30 subjects with mutation of succinate dehydrogenase enzyme subunit B (SDHB) gene and 41 subjects without SDHB mutation). Sixty-nine percent presented with bone metastases (SDHB +/-: 77% vs 63%), 39% with liver metastases (SDHB +/-: 27% vs 47%), and 32% with lung metastases (SDHB +/-: 37% vs 29%). The most common sites of bone involvement were thoracic spine (80%; SDHB+/-: 83% vs 77%), lumbar spine (78%; SDHB +/-: 78% vs 75%), and pelvic and sacral bones (78%; SDHB +/-: 91% vs 65%, P=0.04). Subjects with SDHB mutation also showed significantly higher involvement of long bones (SDHB +/-: 78% vs 30%, P=0.007) than those without the mutation. The best overall sensitivity in detecting bone metastases demonstrated positron emission tomography (PET) with 6-[(18)F]-fluorodopamine ([(18)F]-FDA; 90%), followed by bone scintigraphy (82%), computed tomography or magnetic resonance imaging (CT/MRI; 78%), 2-[(18)F]-fluoro-2-deoxy-d-glucose ([(18)F]-FDG) PET (76%), and scintigraphy with [(123/131)I]-metaiodobenzylguanidine (71%). In subjects with SDHB mutation, imaging modalities with best sensitivities for detecting bone metastases were CT/MRI (96%), bone scintigraphy (95%), and [(18)F]-FDG PET (92%). In subjects without SDHB mutations, the modality with the best sensitivity for bone metastases was [(18)F]-FDA PET (100%). In conclusion, bone scintigraphy should be used in the staging of patients with malignant pheochromocytoma and paraganglioma, particularly in patients with SDHB mutations. As for PET imaging, [(18)F]-FDG PET is highly recommended in SDHB mutation patients, whereas [(18)F]-FDA PET is recommended in patients without the mutation.     

Admixed phenotype of NEDD4L associated periventricular nodular heterotopia: A case report

Rationale:Periventricular nodular heterotopia-7 (PVNH7) is a neurodevelopmental disorder associated with improper neuronal migration during neurogenesis in cortex development caused by pathogenic variants in the NEDD4L gene.Patient concerns:We report the case of a polystigmatized 2-year-old boy having significant symptomatologic overlap with PVNH7, such as delayed psychomotor and mental development, seizures and infantile spasms, periventricular nodular heterotopia, polymicrogyria, cleft palate, 2 to 3 toe syndactyly, hypotonia, microretrognathia, strabismus, and absent speech and walking. The patient showed also distinct symptoms falling outside PVNH7 symptomatology, also present in the proband''s older brother, such as blue sclerae, hydronephrosis, transversal palmar crease (found also in their father), and bilateral talipes equinovarus. In addition, the patient suffered from many other symptoms.Diagnoses:The boy, his brother and their parents were subjected to whole-exome sequencing. Because of uncertainties in symptomatology and inheritance pattern, the top-down approach was hard to apply. Using the bottom-up approach, we identified a known pathogenic variant, NM_001144967.2(NEDD4L):c.2677G>A:p.Glu893Lys, in the proband''s genome that absented in any other analyzed family member, suggesting its de novo origin.Interventions and outcomes:The patient was treated with Convulex 300 mg/mL for the successful seizure control and Euthyrox 25mg for the treatment of thyroid malfunction. He also took various supplements for the metabolism support and digestion regulation. Moreover, the patient underwent the corrective surgeries of cleft palate and talipes equinovarus.Lessons:We successfully identified the causative mutation NM_001144967.2(NEDD4L):c.2677G>A:p.Glu893Lys explaining symptoms overlapping those reported for PVNH7. Symptoms shared with the brother were not explained by this variant, since he was not a carrier of the pathogenic NEDD4L variant. These are most likely not extended phenotypes of PVNH7, rather an independent clinical entity caused by a yet unidentified genetic factor in the family, highlighting thus the importance of thorough evaluation of symptomatology and genomic findings in affected and unaffected family members, when such data are available.     

Transient structural MRI patterns correlate with the motor functions in preterm infants

AimTo explore the relationships between transient structural brain patterns on MRI at preterm and at term-equivalent age (TEA) as a predictor of general movements (GMs) and motor development at 1-year corrected age (CA) in very preterm infants.MethodsIn this prospective study, 30 very preterm infants (median = 28wks; 16 males) had structural magnetic resonance imaging (MRI) at preterm (median = 31wks + 6d) and at TEA (median = 40wks) and neuromotor assessments. The quality of GMs was assessed by Prechtl’s general movements assessment and a detailed analysis of the motor repertoire was performed by calculating a motor optimality score (MOS), both at term age and at 3 months post-term. Motor development at 1-year CA was evaluated with the Infant Motor Profile (IMP). Associations between qualitative MRI findings and neuromotor scores were investigated.ResultsAbnormal GMs and low motor performance at 1-year CA were associated with the poor visibility of transient structural pattern, that is with sagittal strata.InterpretationTransient structural MRI pattern, sagittal strata, at preterm age is related to the quality of GMs and later motor development in preterm infants. This transient fetal brain compartment may be considered as a component of neurobiological basis for early neuromotor behavior, as expressed by GMs.     

Shear stress-induced up-regulation of the intermediate-conductance Ca(2+)-activated K(+) channel in human endothelium

OBJECTIVE: Wall shear stress associated with blood flow is a major stimuli for generation of endothelial vasodilating and antithrombotic factors and it also regulates endothelial gene expression. Activation of endothelial intermediate-conductance Ca(2+)-activated K(+) channels (IK(Ca)) is important for the control of endothelial function by inducing cell hyperpolarization and thus generation of the endothelium-derived hyperpolarizing factor. In the present study we tested whether the IK(Ca) encoding IKCa1 gene is regulated by laminar shear stress (LSS). METHODS: Human umbilical vein endothelial cells (HUVEC) were subjected to LSS with a magnitude of 0.5-15 dyn/cm(2) and time intervals of 2-24 h in a flow cone apparatus. Expression of the IKCa1 gene and IK(Ca)-functions were determined by using real time RT-PCR and patch-clamp techniques. RESULTS: A short 2-4 h-or long 24 h-exposure to a LSS with a low (venous) magnitude of 0.5 dyn/cm(2) had no effect on IKCa1 expression levels. An exposure for 2 and 4 h to LSS with an intermediate magnitude of 5 dyn/cm(2) was also ineffective, whereas an exposure for 24 h induced a significant threefold up-regulation of IKCa1 expression levels. An exposure to LSS with a higher (arterial) magnitude of 15 dyn/cm(2), resulted in an eightfold up-regulation of IKCa1 expression levels after a 4 h-exposure and a fourfold increase of IKCa1 expression levels at 24 h. The increased IKCa1 expression levels following exposure to high levels of LSS resulted in enhanced IK(Ca) whole-cell currents and in an increased hyperpolarization of the endothelium in response to ATP and the IK(Ca) opener 1-EBIO. Inhibition of the mitogen-activated protein kinase/extracellular-signal-regulated kinase (ERK) kinase 1/2 (MEK/ERK) pathway by PD98059 prevented the LSS-induced up-regulation of IKCa1 expression levels and IK(Ca) whole-cell currents indicating that augmentation of IKCa1 expression levels is mediated by the LSS-induced activation of the MEK/ERK pathway. CONCLUSION: Long term exposure to LSS up-regulates expression and function of endothelial IK(Ca). This increase might represent a new important mechanism in endothelial adaptation to altered hemodynamics.     

Assessment of Hemodialysis Adequacy by Ionic Dialysance: Comparison to Standard Method of Urea Removal

Background. The hemodialysis adequacy is one of the most important issues influencing the survival of patients on maintenance hemodialysis (HD). Assessment of measuring the delivered dialysis dose using clearance × time/volume (Kt/V) index requires multiple blood sampling. New methods for assessment of dialysis dose based on ionic dialysance (ID) have been suggested. Online conductivity monitoring (using sodium flux as a surrogate for urea) allows the repeated noninvasive measurement of Kt/V on each HD treatment. In this study we have compared this method with the standard method of estimating Kt/V. Methods. We studied 24 established HD patients over a 4 week time period. Patients were dialyzed using Fresenius 4008S dialysis monitors, equipped with modules to measure ID. Data were manually collected and analyzed using the appropriate statistical software. Urea removal (UR) was measured once a week by a two-pool calculation, estimating an eKt/V. Results. The Kt/V measured by ID highly correlated with the one derived from the measurement of the UR (r = 0.8959, p< 0.0001). The ID underestimated UR by the mean of 6%. The ID varied greatly within individual patients with a median of 1.29 ± 0.22. If the eKt/V ≥ 1.2 is considered adequate, 33% of the patients would have been inadequately dialyzed. The mean HD duration to achieve an adequate dialysis was 4 hours and 47 minutes with high interpatient variability. Conclusion. The ID seems to be an easily obtained measure of the delivered dialysis dose, correlating well with standard UR method. Substantial individual variations imply that repeated measures (ideally for all treatments) are necessary to obtain a real answer to the mean treatment dose being delivered to the patients.