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Reducing neuronal size results in less cell membrane and therefore lower input conductance. Smaller neurons are thus more excitable as seen in their voltage responses to current injections in the soma. However, the impact of a neuron’s size and shape on its voltage responses to synaptic activation in dendrites is much less understood. Here we use analytical cable theory to predict voltage responses to distributed synaptic inputs and show that these are entirely independent of dendritic length. For a given synaptic density, a neuron’s response depends only on the average dendritic diameter and its intrinsic conductivity. These results remain true for the entire range of possible dendritic morphologies irrespective of any particular arborisation complexity. Also, spiking models result in morphology invariant numbers of action potentials that encode the percentage of active synapses. Interestingly, in contrast to spike rate, spike times do depend on dendrite morphology. In summary, a neuron’s excitability in response to synaptic inputs is not affected by total dendrite length. It rather provides a homeostatic input-output relation that specialised synapse distributions, local non-linearities in the dendrites and synaptic plasticity can modulate. Our work reveals a new fundamental principle of dendritic constancy that has consequences for the overall computation in neural circuits.
Prognosis of refractory childhood cancers despite multimodal treatment strategies remains poor. Here, we report a single center experience encountered in 18 patients with refractory solid malignancies treated with adoptive cellular immunotherapy (ACI) from haploidentical or matched donors following hematopoietic stem cell transplantation. While seven patients were in partial and six in complete remission (CR), five patients suffered from relapsed diseases at the time of ACI. 1.5-year probabilities of overall survival (OS) and progression-free survival (PFS) were 19.5% and 16.1% for all patients. Patients in CR showed estimated 1.5-year OS and PFS of 50.1% and 42.7%, respectively. CR was induced or rather sustained in ten children, with two still being alive 9.6 and 9.3 years after ACI. Naïve, central and effector memory T-cells correlated with responses. However, the majority of patients relapsed. Cumulative incidence of relapse was 79.8% at 1.5 years. Acute graft versus host disease (aGVHD) occurred in nine of 18 patients (50%) with aGVHD grade I–II observed in six (33%) and aGVHD grade III seen in three (17%) patients, manageable in all cases.
Altogether, study results indicate that donor-derived ACI at its current state offers palliation but no clear curative benefit for refractory childhood cancers and warrants further improvement.
The precise understanding of the dopaminergic (DA) system and its pharmacological modifications is crucial for diagnosis and treatment of neuropsychiatric disorders, as well as for understanding basic processes, such as motivation and reward. We probed the functional connectivity (FC) of subcortical nuclei related to the DA system according to seed regions defined according to an atlas of subcortical nuclei. We conducted a large pharmaco-fMRI study using a double-blind, placebo-controlled design, where we examined the effect of l -DOPA, a dopamine precursor, and amisulpride, a D2/D3-receptor antagonist on resting-state FC in 45 healthy young adults using a cross-over design. We examined the FC of subcortical nuclei with connection to the reward system and their reaction to opposing pharmacological probing. Amisulpride increased FC from the putamen to the precuneus and from ventral striatum to precentral gyrus. l -DOPA increased FC from the ventral tegmental area (VTA) to the insula/operculum and between ventral striatum and ventrolateral prefrontal cortex and it disrupted ventral striatal and dorsal caudate FC with the medial prefrontal cortex. In an exploratory analysis, we demonstrated that higher self-rated impulsivity goes together with a significant increase in VTA-mid-cingulate gyrus FC during l -DOPA-challenge. Therefore, our DA challenge modulated distinct large-scale subcortical connectivity networks. A dopamine-boost can increase midbrain DA nuclei connectivity to the cortex. The involvement of the VTA-cingulum connectivity in dependence of impulsivity has implications for diagnosis and therapy in disorders like ADHD.
Summary: Understanding the role of short-interfering RNA (siRNA) in diverse biological processes is of current interest and often approached through small RNA sequencing. However, analysis of these datasets is difficult due to the complexity of biological RNA processing pathways, which differ between species. Several properties like strand specificity, length distribution, and distribution of soft-clipped bases are few parameters known to guide researchers in understanding the role of siRNAs. We present RAPID, a generic eukaryotic siRNA analysis pipeline, which captures information inherent in the datasets and automatically produces numerous visualizations as user-friendly HTML reports, covering multiple categories required for siRNA analysis. RAPID also facilitates an automated comparison of multiple datasets, with one of the normalization techniques dedicated for siRNA knockdown analysis, and integrates differential expression analysis using DESeq2. RAPID is available under MIT license at https://github.com/SchulzLab/RAPID. We recommend using it as a conda environment available from https://anaconda.org/bioconda/rapid.
Understanding the role of short-interfering RNA (siRNA) in diverse biological processes is of current interest and often approached through small RNA sequencing. However, analysis of these datasets is difficult due to the complexity of biological RNA processing pathways, which differ between species. Several properties like strand specificity, length distribution, and distribution of soft-clipped bases are few parameters known to guide researchers in understanding the role of siRNAs. We present RAPID, a generic eukaryotic siRNA analysis pipeline, which captures information inherent in the datasets and automatically produces numerous visualizations as user-friendly HTML reports, covering multiple categories required for siRNA analysis. RAPID also facilitates an automated comparison of multiple datasets, with one of the normalization techniques dedicated for siRNA knockdown analysis, and integrates differential expression analysis using DESeq2.
The locus coeruleus (LC) contains the majority of central noradrenergic neurons sending wide projections throughout the entire CNS. The LC is considered to be essential for multiple key brain functions including arousal, attention and adaptive stress responses as well as higher cognitive functions and memory. Electrophysiological studies of LC neurons have identified several characteristic functional features such as low-frequency pacemaker activity with broad action potentials, transient high-frequency burst discharges in response to salient stimuli and an apparently homogeneous inhibition of firing by activation of somatodendritic α2 autoreceptors (α2AR). While stress-mediated plasticity of the α2AR response has been described, it is currently unclear whether different LC neurons projecting to distinct axonal targets display differences in α2AR function. Using fluorescent beads-mediated retrograde tracing in adult C57Bl6/N mice, we compared the anatomical distributions and functional in vitro properties of identified LC neurons projecting either to medial prefrontal cortex, hippocampus or cerebellum. The functional in vitro analysis of LC neurons confirmed their mostly uniform functional properties regarding action potential generation and pacemaker firing. However, we identified significant differences in tonic and evoked α2AR-mediated responses. While hippocampal-projecting LC neurons were partially inhibited by endogenous levels of norepinephrine and almost completely silenced by application of saturating concentrations of the α2 agonist clonidine, prefrontal-projecting LC neurons were not affected by endogenous levels of norepinephrine and only partially inhibited by saturating concentrations of clonidine. Thus, we identified a limited α2AR control of electrical activity for prefrontal-projecting LC neurons indicative of functional heterogeneity in the LC-noradrenergic system.
Sulforaphane is a natural substance found in cruciferous vegetables such as broccoli or cabbage. There are promising results for a number of tumor entities regarding the potential anti-carcinogenic effects of sulforaphane. The experiments designed for this study were performed on prostate carcinoma cells. The aim was to investigate the influence of sulforaphane on the growth behaviour of prostate cancer cells.
Designed as an in-vitro-model, prostate carcinoma cell lines DU145 and PC3 were used in the study. The experiments can be roughly divided into two categories:
• Regulation of cell growth: After the growth inhibitory effect of sulforaphane has been confirmed (MTT test), the proliferation rate (BrdU assay) and apoptosis rate (apoptosis assay) of the cells were measured under the influence of sulforaphane. Studies on clonogenic growth completed this series of experiments.
• Regulation of the cell cycle: After determining the impact of sulforaphane on the phases of the cell cycle (cell cycle assay), the cell cycle-relevant proteins of the cyclin-CDK-axis, the CDK inhibitors p19 and p27 as well as the acetylated histones aH3 and aH4 were analysed (Western Blot).
An additional MTT test was performed to determine a possible induction of resistance by long-term sulforaphane exposure. In addition, the expression profile of CD44 subtypes v4, v5 and v7 under the influence of sulforaphane has been investigated by FACS analysis.
The growth and proliferation rate as well as the clonogenic growth of the prostate carcinoma cells were shown to be inhibited under the influence of sulforaphane in a concentration-dependent manner. Induction of apoptosis has not occurred. The treatment with sulforaphane resulted in a concentration-dependent G2/M arrest of the cell cycle. The level of expression of cyclins A and B and of CDKs 1 and 2 has increased due to sulforaphane exposure. The level of expression of pCDKs has decreased except for a slight increase in pCDK 2 in the DU145 cell line. The CDK inhibitors p19 and p27 were elevated, except for a reduction of p27 in the PC3 cell line. The level of expression of acetylated histones aH3 and aH4 has increased due to sulforaphane treatment. Indications for induction of resistance by long-term use of sulforaphane were not found. Treatment with sulforaphane resulted in an increased expression level of the CD44 subtypes v4, v5 and v7 in a concentration- and time-dependent manner.
The test results fit into the existing findings. The exact processes and relationships of the modes of action are not yet sufficiently understood. Nevertheless, it can be stated that sulforaphane can trigger anticarcinogenic mechanisms at the molecular level also in prostate cancer. Therefore, sulforaphane could eventually be used in clinical practice, whether prophylactically or therapeutically. Further studies, also in clinical settings on humans, are therefore necessary.
Infektionen mit HBV, HCV und HIV verlaufen potentiell chronisch und besonders bei HIV auch tödlich. Komplexe, zum Teil lebenslange Therapien stellen eine große Belastung für die betroffenen Patient*innen und das Gesundheitssystem dar. Die Sicherheit von Blutprodukten hat sich durch Testung auf HBV, HCV und HIV in den vergangenen Jahrzehnten weltweit stark verbessert. Ein kontinuierliches Risikoassessment ist notwendig um diesen Trend aufrecht zu erhalten und auf Änderungen von Einflussfaktoren rechtzeitig reagieren zu können. Die Zusammenschau der Spendenscreeningdaten des DRK Baden-Württemberg Hessen, Nord-Ost, West und des Bayrischen Roten Kreuzes aus den Jahren 2008 bis 2015 ergab, dass in allen Blutbanken unterschiedliche Testsystem verwendet wurden. In zurückliegenden Analysen kamen zudem verschiedene mathematische Modelle zur Anwendung um die TTVI-Risiken in Deutschland abschätzen zu können. Ein direkter Vergleich der Blutspendedienste untereinander sowie eine Analyse der Risikoentwicklung über die Zeit sind somit erschwert. Eine Vereinheitlichung der verwendeten Testsysteme sowie der angewandten Modelle ist anzustreben. Die Anwendungen der Risikomodelle von Busch et al., Hourfar et al. und Weusten et al. ergaben für alle untersuchten Blutbanken Ergebnisse, die geringfügig höher als die beobachteten Risikowerte ausfielen. Das von Weusten et al. entwickelte Modell erwies sich als am besten geeignet zur Risikostratifizierung, da unterschiedliche Eigenschaften der Viren am genauesten berücksichtigt und TTVI-Risiken im Vergleich mit den anderen Modellen sowie zu den beobachteten Fallzahlen konservativ eingeschätzt werden. Nach diesem Modell lagen die Risiken für eine Transmission pro eine Million transfundierter Einheiten in den Jahren 2008 bis 2015 für HBV bei 1, für HCV bei 0,3 und für HIV bei 0,1. Der Vergleich der Zeiträume 1997 bis 2005 und 2008 bis 2015 mittels des Modells von Hourfar et al. ergab aktuell höhere Risiken für TTVIs mit HCV und HIV, wohingegen die Risiken von TTVIs mit HBV gesunken sind. Diese Entwicklungen sind auf erhöhte HCV- und HIV-NAT Only Inzidenzen sowie auf den wachsenden Anteil HBV-geimpfter Spender*innen zurückzuführen. Modellierungen anhand der Spenderscreeningdaten des DRK Baden-Württemberg Hessen mittels des Modells von Weusten et al. zeigten, dass der Faktor Plasmavolumen nicht zur Risikooptimierung geeignet ist. Ein erhöhter Forschungsbedarf im Bereich minimal infektiöse Dosen konnte betont werden, da sich der Einfluss der N50 auf die Risiken als sehr hoch herausstellte und eine Übersicht aktueller Arbeiten teils stark differierende Werte ergab. Die Verkleinerung der Poolgrößen erwies sich als potente Option zur Risikoreduktion, bedarf jedoch weiter Kosten-Nutzen-Analysen bei aktuell bereits sehr geringen TTVI-Risiken. Eine Vergrößerung der Spendeintervalle konnte als ebenso wirkungsvolle Möglichkeit zur Verringerung der Transmissionsrisiken ermittelt und eingeordnet werden. In diesem Zusammenhang wurde überdies gezeigt, dass TTVI-Risiken von Aphereseprodukten um ein Vielfaches höher liegen als die Risiken von Vollblutspenden.
Schilddrüsenknoten stellen mit einer Prävalenz von ca. vierundzwanzig Prozent eine häufige Erkrankung in Deutschland dar. Zahlreiche Studien belegen den erfolgreichen Einsatz der Radiofrequenzablation (RFA) an heißen und kalten Knoten. Sie tritt damit als berechtigte Alternativmethode zum bisherigen Standard Operation und Radiojodtherapie auf. Ziel dieser vorliegenden retrospektiven Studie war der direkte Vergleich einer mit bipolarer RFA behandelten Gruppe heißer und kalter Knoten bezüglich Knotenvolumenreduktion nach drei Monaten, Schmerzempfinden sowie Ultraschall- und laborchemischen Veränderungen.
Material und Methoden:
Die vorliegende retrospektive Untersuchung basiert auf Daten von 40 heißen und 40 kalten benignen Schilddrüsenknoten, die im Mittel 17 ml maßen und mittels bipolarer Radiofrequenzablation behandelt wurden. Alle Patienten unterliefen einer Befunderhebung vor und nach der Therapie sowie nach drei Monaten, bestehend aus vollständigem Schilddrüsenhormonstatus und sonographischen Kriterien. Letztere beinhalteten Messungen des Volumens, der Echogenität, des Blutflusses und der Elastizität. Die übertragene Gesamtenergiemenge [kJ] sowie die Behandlungszeit [s] wurden nach der jeweiligen Intervention dokumentiert. Schmerzen, die während der Behandlung auftraten wurden auf einer 10-Punkte-Rating-Skala gemessen.
Ergebnisse:
Die einmalige bipolare Radiofrequenzablation resultierte in keiner signifikant unterschiedlichen Volumenreduktion zwischen heißen und kalten Knoten nach 3 Monaten (51,57 vs. 54,91 %). Die Hypothese einer geringeren Effektivität der RFA in heißen Knoten aufgrund des „heat sink effect“ ließ sich somit nicht bestätigen. In den einzelnen Gruppen konnte dagegen eine signifikante Volumenreduktion erzielt werden (p < 0, 005).
Es ergaben sich Hinweise auf eine korrelative Reduktion des Knoten- und Schilddrüsenvolumens über 60-Jährigen Probanden, analog zu der im Alter abnehmenden fettfreien Körpermasse.
Der Energie- und Zeitaufwand stieg stets linear mit dem Knotenvolumen an (r > 0,65). Das Schmerzempfinden wurde dagegen nicht von der Knotengröße beeinflusst (p > 0,05). Es bestätigte sich ein stärkeres Schmerzempfinden bei der Verwendung ungekühlter Sonden (Schmerzmedian 3 versus 2).
Weiterhin kam es zu einer signifikanten Abnahme des Blutflusses und der Elastizität durch die RFA in beiden Knotenarten (p < 0,005).
Laborchemisch blieben alle Patienten auch nach Radiofrequenzablation euthyreot. Es konnte eine signifikante Zunahme des TSH-Wertes zwischen Ausgangszeitpunkt T0 und Nachuntersuchungstermin (T2) nachgewiesen werden (p < 0,05) und somit eine Verbesserung des hormonellen Funktionsstatus. Nach Radiofrequenzablation kam es in beiden Gruppen zu einem signifikanten Anstieg des Thyreoglobulin-Spiegels (p < 0,005) als Zeichen einer erfolgreichen Intervention. Die TRAK-, TG- und TPO-Antikörper blieben ohne signifikante Änderung (p > 0,05).
Schlussfolgerung:
Die Radiofrequenzablation stellt eine sichere und effektive Therapiealternative von benignen Schilddrüsenknoten dar und liefert gleichwertige Volumenreduktionen bei heißen und kalten Knoten. Es bedarf weiterer direkter Vergleichsstudien hinsichtlich der Wirksamkeit auf die Knotenart sowie Langzeitbeobachtungen, um abschließende Aussagen darüber treffen zu können.
BOLD signatures of sleep
(2019)
Sleep can be distinguished from wake by changes in brain electrical activity, typically assessed using electroencephalography (EEG). The hallmark of non-rapid-eye-movement sleep are two major EEG events: slow waves and spindles. Here we sought to identify possible signatures of sleep in brain hemodynamic activity, using simultaneous fMRI-EEG. We found that, during the transition from wake to sleep, blood-oxygen-level-dependent (BOLD) activity evolved from a mixed-frequency pattern to one dominated by two distinct oscillations: a low-frequency (~0.05Hz) oscillation prominent in light sleep and a high-frequency (~0.17Hz) oscillation in deep sleep. The two BOLD oscillations correlated with the occurrences of spindles and slow waves, respectively. They were detectable across the whole brain, cortically and subcortically, but had different regional distributions and opposite onset patterns. These spontaneous BOLD oscillations provide fMRI signatures of basic sleep processes, which may be employed to study human sleep at spatial resolution and brain coverage not achievable using EEG.