Target- and Maturation-Specific Membrane-Associated Molecules Determine the Ingrowth of Entorhinal Fibers into the Hippocampus

AbstractIn this study the role of membrane-associated molecules involved in entorhinohippocampal pathfinding was examined. First outgrowth preferences of entorhinal neurites were analyzed on membrane carpets obtained from their proper target area, the hippocampus, and compared to preferences on control membranes from brain regions which do not receive afferent connections from the entorhinal cortex. On a substrate consisting of alternating lanes of hippocampal and control membranes, entorhinal neurites exhibited a strong tendency to grow on lanes of hippocampal membrane. These tissue-specific outgrowth preferences were maintained even on membrane preparations from adult brain tissue devoid of myelin. To determine the possible maturation dependence of these membranes, we examined guidance preferences of entorhinal neurites on hippocampal membranes of different developmental stages ranging from embryonic to postnatal and adult. Given a choice between alternating lanes of embryonic (E15–E16) and neonatal (P0–P1) hippocampal membranes, entorhinal neurites preferred to extend on neonatal membranes. No outgrowth preferences were observed on membranes obtained between E19 and P10. From P10 onward there was a reoccurrence of a preference for postnatal membrane lanes when neurites were presented with a choice between P15, P30, and adult membranes (>P60). This choice behavior of entorhinal neurites temporally correlates with the ingrowth of the perforant path into the hippocampus and with the stabilization of this brain area in vivo. Experiments in which postnatal and adult hippocampal membranes were heat inactivated or treated to remove molecules sensitive to phosphatidylinositol-specific phospholipase C demonstrated that entorhinal fiber preferences were controlled in this assay by attractive guidance cues and were independent of phosphatidylinositol-sensitive linked molecules. Moreover, entorhinal neurites displayed a positive discrimination for membrane-associated guidance cues of their target field, thus preferring to grow on membranes from the molecular layer of the dentate gyrus compared with CA3 or hilus membranes. Heat-inactivation experiments indicated that preferential growth of entorhinal axons is due to a specific attractivity of the molecular layer substrate. The data presented demonstrate that outgrowth of entorhinal fibers on hippocampal membranes is target and maturation dependent

Kidney function in the very elderly with hypertension: data from the hypertension in the very elderly (HYVET) trial.

BACKGROUND: numerous reports have linked impaired kidney function to a higher risk of cardiovascular events and mortality. There are relatively few data relating to kidney function in the very elderly. METHODS: the Hypertension in the Very Elderly Trial (HYVET) was a randomised placebo-controlled trial of indapamide slow release 1.5mg ± perindopril 2-4 mg in those aged ≥80 years with sitting systolic blood pressures of ≥160 mmHg and diastolic pressures of <110 mmHg. Kidney function was a secondary outcome. RESULTS: HYVET recruited 3,845 participants. The mean baseline estimated glomerular filtration rate (eGFR) was 61.7 ml/min/1.73 m(2). When categories of the eGFR were examined, there was a possible U-shaped relationship between eGFR, total mortality, cardiovascular mortality and events. The nadir of the U was the eGFR category ≥60 and <75 ml/min/1.73 m(2). Using this as a comparator, the U shape was clearest for cardiovascular mortality with the eGFR <45 ml/min/1.73 m(2) and ≥75 ml/min/1.73 m(2) showing hazard ratios of 1.88 (95% CI: 1.2-2.96) and 1.36 (0.94-1.98) by comparison. Proteinuria at baseline was also associated with an increased risk of later heart failure events and mortality. CONCLUSIONS: although these results should be interpreted with caution, it may be that in very elderly individuals with hypertension both low and high eGFR indicate increased risk

Acceptance of E-Mental Health Services for Different Application Purposes Among Psychotherapists in Clinical Training in Germany and Switzerland: Secondary Analysis of a Cross-Sectional Survey

Background: Despite solid evidence supporting the efficacy of electronic mental health (EMH) services, their acceptance among psychotherapists is limited and uptake rates remain low. However, the acceptance of different EMH services has yet barely been examined in future generations of psychotherapists in a differentiated manner. The aims of this study were (1) to elaborate the intention to use various EMH services for different application purposes and (2) to determine predictors of EMH service acceptance among psychotherapists in clinical training (PiT). Materials and Methods: Our paper is based on a secondary data analysis of a cross-sectional survey. Respondents were recruited via recognized educational institutions for psychotherapy within Germany and the German-speaking part of Switzerland between June and July of 2020. The survey contained items on the intention to use different EMH services (i.e., guided and unguided programs, virtual reality, psychotherapy by telephone and videoconference) for various application purposes (i.e., prevention, treatment addition, treatment substitute, aftercare). Potential predictors of EMH service acceptance (e.g., barriers and advantages) were examined based on an extension of the Unified Theory of Acceptance and Use of Technology (UTAUT). Results: Most of the n = 216 respondents were female (88.4%) and located in Germany (72.2%). General acceptance of EMH was moderate (M = 3.4, SD = 1.12, range 1–5), while acceptance of psychotherapy via videoconference was highest (M = 3.7, SD = 1.15) and acceptance of unguided programs was lowest (M = 2.55, SD = 1.14). There was an interaction effect of EMH service and application purpose (η2 = 0.21). Barriers and advantages both had a uniform influence on EMH service acceptance (Pr > 0.999), while impersonality, legal concerns, concerns about therapeutic alliance, simplified information provision, simplified contact maintenance, time flexibility, and geographic flexibility were significant predictors (all p 0.999). Conclusions: The intention to use different EMH services varied between application purposes among PiT. To increase acceptance of EMH services and reduce misconceptions, we identified predictors that should be addressed in future acceptance-facilitating interventions when educating PiT

Interleukin-1 beta and neurotrophin-3 synergistically promote neurite growth in vitro

Pro-inflammatory cytokines such as interleukin-1 beta (IL-1β) are considered to exert detrimental effects during brain trauma and in neurodegenerative disorders. Consistently, it has been demonstrated that IL-1β suppresses neurotrophin-mediated neuronal cell survival rendering neurons vulnerable to degeneration. Since neurotrophins are also well known to strongly influence axonal plasticity, we investigated here whether IL-1β has a similar negative impact on neurite growth. We analyzed neurite density and length of organotypic brain and spinal cord slice cultures under the influence of the neurotrophins NGF, BDNF, NT-3 and NT-4. In brain slices, only NT-3 significantly promoted neurite density and length. Surprisingly, a similar increase of neurite growth was induced by IL-1β. Additionally, both factors increased the number of brain slices displaying maximal neurite growth. Furthermore, the co-administration of IL-1β and NT-3 significantly increased the number of brain slices displaying maximal neurite growth compared to single treatments. These data indicate that these two factors synergistically stimulate two distinct aspects of neurite outgrowth, namely neurite density and neurite length from acute organotypic brain slices

Treatment of Relapsing Paralysis in Experimental Encephalomyelitis by Targeting Th1 Cells through Atorvastatin

Statins, known as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, exhibit numerous functions related to inflammation, such as MHC class II down-regulation, interference with T cell adhesion, and induction of apoptosis. Here we demonstrate that both subcutaneous and oral administration of atorvastatin inhibit the development of actively induced chronic experimental autoimmune encephalomyelitis in SJL/J mice and significantly reduce the inflammatory infiltration into the central nervous system (CNS). When treatment was started after disease onset, atorvastatin reduced the incidence of relapses and protected from the development of further disability. Both the reduced autoreactive T cell response measured by proliferation toward the encephalitogenic peptide PLP139–151 and the cytokine profile indicate a potent blockade of T helper cell type 1 immune response. In in vitro assays atorvastatin not only inhibited antigen-specific responses, but also decreased T cell proliferation mediated by direct TCR engagement independently of MHC class II and LFA-1. Inhibition of proliferation was not due to apoptosis induction, but linked to a negative regulation on cell cycle progression. However, early T cell activation was unaffected, as reflected by unaltered calcium fluxes. Thus, our results provide evidence for a beneficial role of statins in the treatment of autoimmune attack on the CNS

Activation of Microglial Poly(ADP-Ribose)-Polymerase-1 by Cholesterol Breakdown Products during Neuroinflammation: a Link between Demyelination and Neuronal Damage

Multiple sclerosis (MS) is a chronic demyelinating disease in which it has only recently been suggested that damage to neuronal structures plays a key role. Here, we uncovered a link between the release of lipid breakdown products, found in the brain and cerebrospinal fluid (CSF) of MS patients as well as in experimental autoimmune encephalomyelitis, and neuronal damage mediated by microglial activation. The concentrations of the breakdown product 7-ketocholesterol detected in the CSF of MS patients were capable of inducing neuronal damage via the activation and migration of microglial cells in living brain tissue. 7-ketocholesterol rapidly entered the nucleus and activated poly(ADP-ribose)-polymerase (PARP)-1, followed by the expression of migration-regulating integrins CD11a and intercellular adhesion molecule 1. These findings reveal a novel mechanism linking demyelination and progressive neuronal damage, which might represent an underlying insidious process driving disease beyond a primary white matter phenomenon and rendering the microglial PARP-1 a possible antiinflammatory therapeutic target

Non-cell autonomous and non-catalytic activities of ATX in the developing brain

The intricate formation of the cerebral cortex requires a well-coordinated series of events, which are regulated at the level of cell-autonomous and non-cell autonomous mechanisms. Whereas cell-autonomous mechanisms that regulate cortical development are well-studied, the non cell-autonomous mechanisms remain poorly understood. A non-biased screen allowed us to identify Autotaxin (ATX) as a non cell-autonomous regulator of neural stem cell proliferation. ATX (also known as ENPP2) is best known to catalyze lysophosphatidic acid (LPA) production. Our results demonstrate that ATX affects the localization and adhesion of neuronal progenitors in a cell autonomous and non-cell autonomous manner, and strikingly, this activity is independent from its catalytic activity in producing LPA

How to estimate glomerular filtration rate in sub-Saharan Africa: design and methods of the African Research into Kidney Diseases (ARK) study.

BACKGROUND: Chronic kidney disease (CKD) is a substantial cause of morbidity and mortality worldwide with disproportionate effects in sub-Saharan Africa (SSA). The optimal methods to estimate glomerular filtration rate (GFR) and therefore to determine the presence of CKD in SSA are uncertain. We plan to measure iohexol excretion to accurately determine GFR in Malawi, South Africa and Uganda. We will then assess the performance of existing equations to estimate GFR and determine whether a modified equation can better improve estimation of GFR in sub-Saharan Africa. METHODS: The African Research on Kidney Disease (ARK) study is a three-country study embedded within existing cohorts. We seek to enrol 3000 adults > 18 years based on baseline serum creatinine. Study procedures include questionnaires on socio-demographics and established risk factors for kidney disease along with anthropometry, body composition, blood pressure, blood chemistry and urine microscopy and albuminuria. We will measure GFR (mGFR) by plasma clearance of iohexol at 120, 180 and 240 min. We will compare eGFR determined by established equations with mGFR using Bland-Altman plots. We will use regression methods to estimate GFR and compare the newly derived model with existing equations. DISCUSSION: Through the ARK study, we aim to establish the optimal approach to estimate GFR in SSA. The study has the advantage of drawing participants from three countries, which will increase the applicability of the findings across the region. It is also embedded within established cohorts that have longitudinal information and serial measures that can be used to characterize kidney disease over a period of time. This will help to overcome the limitations of previous research, including small numbers, selected population sub-groups, and lack of data on proteinuria. The ARK collaboration provides an opportunity for close working partnerships across different centres, using standardized protocols and measurements, and shared bio-repositories. We plan to build on the collaboration for this study for future work on kidney disease in sub-Saharan Africa, and welcome additional partners from across the continent

Оптимизация работы установок электроцентробежных насосов в процессе добычи нефти на Снежном нефтегазоконденсатном месторождении (Томская область)

Объектом исследования является Снежное нефтегазоконденсатное месторождение. Цель работы – изучить оптимизацию работы установок электроцентробежных насосов в процессе добычи нефти на Снежном нефтегазоконденсатном месторождении. В процессе работы были рассмотрены причины отказов в работе установок электроцентробежных насосов, выполнен статистический анализ отказов в работе скважин, оборудованных УЭЦН, показавший, что большая доля причин проведения подземных ремонтов (до 15%) связана с рассогласованием гидравлических характеристик центробежного насоса и пласта.The object of research is the Snezhnoye oil and gas condensate field. The purpose of the work is to study the optimization of the operation of electric centrifugal pump installations in the process of oil production at the Snezhnoye oil and gas condensate field. During the work, the reasons for failures in the operation of electric centrifugal pump installations were considered, a statistical analysis of failures in the operation of wells equipped with ESP was performed, which showed that a large share of the reasons for underground repairs (up to 15%) is associated with a mismatch in the hydraulic characteristics of the centrifugal pump and the formation