Gastroesophageal Reflux and Body Movement in Infants: Investigations with Combined Impedance-pH and Synchronized Video Recording

The aim of this paper was to investigate the temporal association of gastroesophageal reflux (GER) and body movement in infants. GER were registered by combined impedance-pH, documentation of body movement was done by video. Videorecording time (Vt) was divided into “resting time” and “movement time” and analyzed for occurrence of GER. Association was defined as movement 1 minute before/after the beginning of a GER. Statistical evaluation was by Fisher's exact test. In 15 infants, 341 GER were documented during Vt (86 hours). 336 GER (99%) were associated with movement, only 5 episodes (1%) occured during resting time. Movement was significantly associated with the occurrence of GER (P < .0001). There is a strong temporal association between GER and body movement in infants. However, a clear distinction between cause and effect could not be made with the chosen study design. Combined impedance-pH has proven to be the ideal technique for this approach

Positive effect of the combination of multilevel contracture release and glucocorticoid treatment in Duchenne muscular dystrophy

Purpose: In the 1980s the first results of an early multilevel contracture release (MLCR) in patients suffering from progressive Duchenne muscular dystrophy (DMD) showed a positive effect on ambulation. Despite the demonstrated positive effects of prolongation of walking this treatment is not part of current guidelines. The aim of our study was to evaluate the effect of MLCR as well as its combination with glucocorticoid (GC) treatment on ambulation. Methods: Data of all boys (n = 86) with DMD treated in our outpatient department were analyzed regarding the treatment and loss of independent ambulation. In all, 23 were treated with GC only, ten were operated on, 21 received GC and underwent MLCR and 32 received neither of the two treatments. Results: The analysis of the loss of independent ambulation in our cohort showed a comparable extension of the ambulatory period between the GC-treated and MLCR-treated boys (p = 0.008 and p = 0.005, respectively). Furthermore, an additive effect of both therapies was found; patients with DMD who had both treatments were able to walk two years longer than those with only one of the two treatment options (p<0.001). Conclusion: Standard GC treatment and early MLCR in lower limbs have an independent positive effect on prolongation of ambulation in patients with DMD. In our cohort, the combination of both therapies is significantly more effective than each therapy alone. We suggest both should be offered to all DMD patients eligible. Level of evidence: III

In-vitro Selektion von DNA-Molekülen für Schimmelpilz-Biosensoren

Schimmelpilze in Innenräumen können bei den Bewohnern verschiedene Gesundheitsprobleme auslösen, wie beispielsweise Mykosen, Mykotoxikosen und Allergien. Standardmethoden für die Quantifizierung und Identifizierung der Pilze sind oft zeitaufwändig und nur durch qualifiziertes Personal durchführbar. Deshalb entwickeln wir unter Nutzung des SELEX-Verfahrens ssDNA – Aptamere für die Sporen von Aspergillus- und Penicillium- Stämmen, die in Biosensoren für die Detektion von Schimmelpilzen in Innenräumen eingesetzt werden sollen. Beide Stämme gehören zu den häufig in Innenräumen auftretenden Schimmelpilzen, von denen bekannt ist, daß sie verschiedene Mykotoxine freisetzen. Die Gewinnung von Aptameren erfolgt unter Verwendung einer evolutionären Methode, dem SELEX-Verfahren (Systematic Evolution of Ligands by Exponential Enrichment). Dabei werden in einem Bindungsschritt aus einem Pool verschiedenster einzelsträngiger DNA-Moleküle (ss DNA) zunächst diejenigen gewonnen, die aufgrund ihrer individuellen Struktur bevorzugt an das Zielmolekül binden. Nach ihrer Ablösung von den Zielmolekülen (intakte Sporen) werden sie mittels PCR vervielfältigt. Dabei enstehen Doppelstränge, von denen die für die Bindungsreaktion an die Zielmoleküle überflüssigen Gegenstränge abgetrennt werden müssen. Dies geschieht über die Spaltung einer Ribose-Bindung im Gegenstrang, die durch modifizierter Primer eingeführt wurde. In dem auf diese Weise entstandenen Pool sind nun besser bindende ssDNA Moleküle angereichert, die für die Bindungsreaktion der nächsten Selektionsrunde zur Verfügung stehen. Dieser Prozeß wird so lange wiederholt, bis keine weitere Verbesserung der Affinität erfolgt. Die Affinität der auf diesem Wege hergestellten Aptamere wird unter Verwendung verschiedener Methoden getestet. Dazu gehören ein Standard-Filter-Bindungs-Test, eine fluoreszenz-mikroskopische Methode, die Messung der Fluoreszenzdepolarisation und die Anwendung der Resonant Mirror Spektroskopie

RNA Aptamer Evolution: Two Decades of SELEction

Aptamers are small non-coding RNAs capable of recognizing, with high specificity and affinity, a wide variety of molecules in a manner that resembles antibodies. This class of nucleic acids is the resulting product of applying a well-established screening method known as SELEX. First developed in 1990, the SELEX process has become a powerful tool to select structured oligonucleotides for the recognition of targets, starting with small molecules, going through protein complexes until whole cells. SELEX has also evolved along with new technologies positioning itself as an alternative in the design of a new class of therapeutic agents in modern molecular medicine. This review is an historical follow-up of SELEX method over the two decades since its first appearance

Design of small molecule-responsive microRNAs based on structural requirements for Drosha processing

MicroRNAs (miRNAs) are prevalent regulatory RNAs that mediate gene silencing and play key roles in diverse cellular processes. While synthetic RNA-based regulatory systems that integrate regulatory and sensing functions have been demonstrated, the lack of detail on miRNA structure–function relationships has limited the development of integrated control systems based on miRNA silencing. Using an elucidated relationship between Drosha processing and the single-stranded nature of the miRNA basal segments, we developed a strategy for designing ligand-responsive miRNAs. We demonstrate that ligand binding to an aptamer integrated into the miRNA basal segments inhibits Drosha processing, resulting in titratable control over gene silencing. The generality of this control strategy was shown for three aptamer–small molecule ligand pairs. The platform can be extended to the design of synthetic miRNAs clusters, cis-acting miRNAs and self-targeting miRNAs that act both in cis and trans, enabling fine-tuning of the regulatory strength and dynamics. The ability of our ligand-responsive miRNA platform to respond to user-defined inputs, undergo regulatory performance tuning and display scalable combinatorial control schemes will help advance applications in biological research and applied medicine

Two-Way Quantum Time Transfer: A Method for Daytime Space-Earth Links

Remote clock synchronization is crucial for many classical and quantum network applications. Current state-of-the-art remote clock synchronization techniques achieve femtosecond-scale clock stability utilizing frequency combs, which are supplementary to quantum-networking hardware. Demonstrating an alternative, we synchronize two remote clocks across our freespace testbed using a method called two-way quantum time transfer (QTT). In one second we reach picosecond-scale timing precision under very lossy and noisy channel conditions representative of daytime space-Earth links with commercial off-the-shelf quantum-photon sources and detection equipment. This work demonstrates how QTT is potentially relevant for daytime space-Earth quantum networking and/or providing high-precision secure timing in GPS-denied environments.Comment: arXiv admin note: text overlap with arXiv:2211.0073

Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches

Aptamers are oligonucleotide ligands, either RNA or ssDNA, selected for high-affinity binding to molecular targets, such as small organic molecules, proteins or whole microorganisms. While reports of new aptamers are numerous, characterization of their specific interaction is often restricted to the affinity of binding (KD). Over the years, crystal structures of aptamer-protein complexes have only scarcely become available. Here we describe some relevant technical issues about the process of crystallizing aptamer-protein complexes and highlight some biochemical details on the molecular basis of selected aptamer-protein interactions. In addition, alternative experimental and computational approaches are discussed to study aptamer-protein interactions.

Concurrent axon and myelin destruction differentiates X-linked adrenoleukodystrophy from multiple sclerosis

Cerebral disease manifestation occurs in about two thirds of males with X-linked adrenoleukodystrophy (CALD) and is fatally progressive if left untreated. Early histopathologic studies categorized CALD as an inflammatory demyelinating disease, which led to repeated comparisons to multiple sclerosis (MS). The aim of this study was to revisit the relationship between axonal damage and myelin loss in CALD. We applied novel immunohistochemical tools to investigate axonal damage, myelin loss and myelin repair in autopsy brain tissue of eight CALD and 25 MS patients. We found extensive and severe acute axonal damage in CALD already in prelesional areas defined by microglia loss and relative myelin preservation. In contrast to MS, we did not observe selective phagocytosis of myelin, but a concomitant decay of the entire axon-myelin unit in all CALD lesion stages. Using a novel marker protein for actively remyelinating oligodendrocytes, breast carcinoma-amplified sequence (BCAS) 1, we show that repair pathways are activated in oligodendrocytes in CALD. Regenerating cells, however, were affected by the ongoing disease process. We provide evidence that—in contrast to MS—selective myelin phagocytosis is not characteristic of CALD. On the contrary, our data indicate that acute axonal injury and permanent axonal loss are thus far underestimated features of the disease that must come into focus in our search for biomarkers and novel therapeutic approaches

In vitro selection of oligonucleotides that bind double-stranded DNA in the presence of triplex-stabilizing agents

A SELEX approach has been developed in order to select oligonucleotides that bind double-stranded DNA in the presence of a triplex-stabilizing agent, and was applied to a target sequence containing an oligopurine–oligopyrimidine stretch. After only seven rounds of selection, the process led to the identification of oligonucleotides that were able to form triple helices within the antiparallel motif. Inspection of the selected sequences revealed that, contrary to GC base pair which were always recognized by guanines, recognition of AT base pair could be achieved by either adenine or thymine, depending on the sequence context. While thymines are strongly preferred for several positions, some others can accommodate the presence of adenines. These results contribute to set the rules for designing oligonucleotides that form stable triple helices in the presence of triplex-stabilizing agents at physiological pH. They set the basis for further experiments regarding extension of potential target sequences for triple-helix formation or recognition of ligand–DNA complexes