Publications by authors named "Arnold U"

This multi-arm, parallel group, single-blinded randomised controlled trial aimed to assess three commercially available mouthwashes effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This manuscript has been written in accordance with the CONSORT statement. Eligible participants were SARS-CoV-2 positive with a positive test in the last 72 h.

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Crimean-Congo Haemorrhagic Fever Virus (CCHFV) is spread by infected ticks or direct contact with blood, tissues and fluids from infected patients or livestock. Infection with CCHFV causes severe haemorrhagic fever in humans which is fatal in up to 83 % of cases. CCHFV is listed as a priority pathogen by the World Health Organization (WHO) and there are currently no widely-approved vaccines.

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A pathogen inactivation step during collection or processing of clinical samples has the potential to reduce infectious risks associated with diagnostic procedures. It is essential that these inactivation methods are demonstrated to be effective, particularly for non-traditional inactivation reagents or for commercial products where the chemical composition is undisclosed. This study assessed inactivation effectiveness of twenty-four next-generation (guanidine-free) nucleic acid extraction lysis buffers and twelve rapid antigen test buffers against SARS-CoV-2, the causative agent of COVID-19.

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Background: The public health impact of Chikungunya virus (CHIKV) is often underestimated. Usually considered a mild condition of short duration, recent outbreaks have reported greater incidence of severe illness, fatality, and longer-term disability. In 2018/19, Eastern Sudan experienced the largest epidemic of CHIKV in Africa to date, affecting an estimated 487,600 people.

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The COVID-19 pandemic has necessitated a multifaceted rapid response by the scientific community, bringing researchers, health officials, and industry together to address the ongoing public health emergency. To meet this challenge, participants need an informed approach for working safely with the etiological agent, the novel human coronavirus SARS-CoV-2. Work with infectious SARS-CoV-2 is currently restricted to high-containment laboratories, but material can be handled at a lower containment level after inactivation.

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Article Synopsis
  • In 2015, a study at an Ebola treatment center in Guinea assessed data from 286 EVD patients, focusing on factors like blood chemistry and the impact of favipiravir treatment.
  • 163 patients were selected for a detailed analysis, revealing that favipiravir-treated patients had a lower case-fatality rate and longer survival times compared to untreated patients.
  • While favipiravir treatment did not show a statistically significant impact on overall survival rates, it indicated a trend towards better outcomes consistent with previous research.
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A comprehensive, integrated support programme for new international students of medicine has been developed, implemented and evaluated at the Charité. The objectives of the programme were improved social integration, orientation on the study program and Charité campus, as well as qualification in medical specialist language. The "Charité Orientation Module for International Students" (ChOIS) was designed by a working group with a variety of expertise in the field of international students.

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Virus infections induce sensitive antiviral responses within the host cell. The RNA helicase retinoic acid-inducible gene I (RIG-I) is a key sensor of influenza virus RNA that induces the expression of antiviral type I interferons. Recent evidence suggests a complex pattern of RIG-I regulation involving multiple interactions and cellular sites.

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The conformational attributes of proline can have a substantial effect on the folding of polypeptide chains into a native structure and on the stability of that structure. Replacing the 4S hydrogen of a proline residue with fluorine is known to elicit stereoelectronic effects that favor a cis peptide bond. Here, semisynthesis is used to replace a cis-proline residue in ribonuclease A with (2S,4S)-4-fluoroproline.

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Cytotoxic ribonucleases such as the leopard frog derivative Ranpirnase (Onconase(®)) have emerged as a valuable new class of cancer therapeutics. Clinical trials employing single agent Ranpirnase in cancer patients have demonstrated significant clinical activity and surprisingly low immunogenicity. However, dose-limiting toxicity due to unspecific uptake of the RNase into non-cancerous cells is reached at relatively low concentrations of > 1 mg/m(2).

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Due to its frequent overexpression in a variety of solid tumors the epidermal growth factor receptor (EGFR) is a well-established target for therapeutic interventions in epithelial cancers. In order to target EGFR in head and neck cancer, we have generated a ribonuclease (RNase) fusion protein comprising a humanized anti-EGFR antibody single-chain Fv fragment (scFv) and Ranpirnase, an RNase from Rana pipiens. Fusion of Ranpirnase to the N-terminus of the scFv via a flexible glycine-serine linker (G4S)3 resulted in very poor cytotoxicity of the fusion protein.

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Comparative studies on homologous proteins can provide knowledge on how limited changes in the primary structure find their expression in large effects on catalytic activity, stability or the folding behavior. For more than half a century, members of the ribonuclease A superfamily have been the subject of a myriad of studies on protein folding and stability. Both the unfolding and refolding kinetics as well as the structure of several folding intermediates of ribonuclease A have been characterized in detail.

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Peptidyl-prolyl isomerization reactions can make for rate-limiting steps in protein folding due to their high activation energy. Onconase, an unusually stable ribonuclease A homologue from the Northern leopard frog, contains four trans proline residues in its native state. During the refolding from its guanidine hydrochloride unfolded state, which includes the formation of a folding intermediate, the slowest of the three phases has earlier been attributed to a cis-to-trans peptidyl-prolyl isomerization reaction.

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Unfolding by chemical denaturants and the linear extrapolation method are widely used to determine the free energy of proteins. Ribonuclease 3 from bullfrog shows an extraordinary behavior in guanidinium hydrochloride in comparison to its homologues ribonuclease A and onconase with a high transition midpoint of denaturation but an apparently low cooperativity. The analysis of the interdependence of thermal, urea-, and guanidine hydrochloride-induced unfolding revealed that whereas addition of urea resulted in the expected destabilization of all three proteins, guanidine hydrochloride acted diversely: in contrast to ribonuclease A and onconase, both of which were destabilized as expected, low concentrations of guanidine hydrochloride significantly stabilize ribonuclease 3 from bullfrog.

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The introduction of non-natural modules could provide unprecedented control over folding/unfolding behavior, conformational stability, and biological function of proteins. Success requires the interrogation of candidate modules in natural contexts. Here, expressed protein ligation is used to replace a reverse turn in bovine pancreatic ribonuclease (RNase A) with a synthetic β-dipeptide: β²-homoalanine-β³-homoalanine.

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Among the strategies that employ genetic engineering to stabilize proteins, the introduction of disulfide bonds has proven to be a very potential approach. As, however, the replacement of amino acid residues by cysteines and the subsequent formation of the covalent bond can result in a severe deformation of the parental protein structure, the stabilization effect is strongly context dependent. Alternatively, the introduction of charged amino acid residues at the surface, which may result in the formation of extra ionic interactions or hydrogen bonds, provide propitious means for protein stabilization.

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A No Mix sanitation system was installed in a dormitory at the University of Can Tho in Vietnam, with the objective of recycling nutrients from source separated urine. This paper presents a pilot scale evaporation technology, and investigates the feasibility of recovering nitrogen and phosphorus from human urine by solar still for use as fertilizer. After 26 days of sun exposure, 360 g of solid fertilizer material was recovered from 50 L undiluted urine.

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Background: Injection laryngoplasty is an option for treatment of dysphonia following vocal fold paralysis. Modified fibrin glue with suspended chondrocytes might be a favorable cell-based material for permanent vocal fold medialization.

Methods: We compared fibrin glue with suspended chondrocytes to collagen and hyaluronic acid gels concerning alteration of vocal fold vibration and correct intralaryngeal placement after intralaryngeal injection into porcine larynges.

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Because of their ability to degrade RNA, RNases are potent cytotoxins. The cytotoxic activity of most members of the RNase A superfamily, however, is abolished by the cytosolic ribonuclease inhibitor (RI). RNase A tandem enzymes, in which two RNase A molecules are artificially connected by a peptide linker, and thus have a pseudodimeric structure, exhibit remarkable cytotoxic activity.

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The S-peptide and S-protein components of bovine pancreatic ribonuclease form a noncovalent complex with restored ribonucleolytic activity. Although this archetypal protein-fragment complementation system has been the object of historic work in protein chemistry, intrinsic limitations compromise its utility. Modern methods are shown to overcome those limitations and enable new applications.

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Urine contains a considerable amount of nutrients and potentially could be used as supplement commercial mineral fertilizer; however, it carries risk of contamination. The effect of urine storage as a simple treatment method was examined under tropical conditions. Initial concentrations of total coliforms (2.

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The two homologous proteins ribonuclease A and onconase fold through conserved initial contacts but differ significantly in their thermodynamic stability. A disulfide bond is located in the folding initiation site of onconase (the C-terminal part of the protein molecule) that is missing in ribonuclease A, whereas the other three disulfide bonds of onconase are conserved in ribonuclease A. Consequently, the deletion of this C-terminal disulfide bond (C87-C104) allows the impact of the contacts in this region on the folding of onconase to be studied.

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A promising approach to unravel the relationship between sequence information, tertiary structure, and folding mechanism of proteins is the analysis of the folding behavior of proteins with low sequence identity but comparable tertiary structures. Ribonuclease A (RNase A) and its homologues, forming the RNase A superfamily, provide an excellent model system for respective studies. RNase A has been used extensively as a model protein for folding studies.

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