The newly identified severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a pandemic respiratory disease. Moreover, thromboembolic events throughout the body, including in ...the CNS, have been described. Given the neurological symptoms observed in a large majority of individuals with COVID-19, SARS-CoV-2 penetrance of the CNS is likely. By various means, we demonstrate the presence of SARS-CoV-2 RNA and protein in anatomically distinct regions of the nasopharynx and brain. Furthermore, we describe the morphological changes associated with infection such as thromboembolic ischemic infarction of the CNS and present evidence of SARS-CoV-2 neurotropism. SARS-CoV-2 can enter the nervous system by crossing the neural-mucosal interface in olfactory mucosa, exploiting the close vicinity of olfactory mucosal, endothelial and nervous tissue, including delicate olfactory and sensory nerve endings. Subsequently, SARS-CoV-2 appears to follow neuroanatomical structures, penetrating defined neuroanatomical areas including the primary respiratory and cardiovascular control center in the medulla oblongata.
Diagnostic electron microscopy (DEM) was an essential component of viral diagnosis until the development of highly sensitive nucleic acid amplification techniques (NAT). The simple negative staining ...technique of DEM was applied widely to smallpox diagnosis until the world-wide eradication of the human-specific pathogen in 1980. Since then, the threat of smallpox re-emerging through laboratory escape, molecular manipulation, synthetic biology or bioterrorism has not totally disappeared and would be a major problem in an unvaccinated population. Other animal poxviruses may also emerge as human pathogens. With its rapid results (only a few minutes after arrival of the specimen), no requirement for specific reagents and its "open view", DEM remains an important component of virus diagnosis, particularly because it can easily and reliably distinguish smallpox virus or any other member of the orthopoxvirus (OPV) genus from parapoxviruses (PPV) and the far more common and less serious herpesviruses (herpes simplex and varicella zoster). Preparation, enrichment, examination, internal standards and suitable organisations are discussed to make clear its continuing value as a diagnostic technique.
Diagnostic electron microscopy has two advantages over enzyme-linked immunosorbent assay and nucleic acid amplification tests. After a simple and fast negative stain preparation, the undirected, ..."open view" of electron microscopy allows rapid morphologic identification and differential diagnosis of different agents contained in the specimen. Details for efficient sample collection, preparation, and particle enrichment are given. Applications of diagnostic electron microscopy in clinically or epidemiologically critical situations as well as in bioterrorist events are discussed. Electron microscopy can be applied to many body samples and can also hasten routine cell culture diagnosis. To exploit the potential of diagnostic electron microscopy fully, it should be quality controlled, applied as a frontline method, and be coordinated and run in parallel with other diagnostic techniques.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
SARS coronavirus continues to cause sporadic cases of severe acute respiratory syndrome (SARS) in China. No active or passive immunoprophylaxis for disease induced by SARS coronavirus is available. ...We investigated prophylaxis of SARS coronavirus infection with a neutralising human monoclonal antibody in ferrets, which can be readily infected with the virus. Prophylactic administration of the monoclonal antibody at 10 mg/kg reduced replication of SARS coronavirus in the lungs of infected ferrets by 3·3 logs (95% Cl 2·6–4·0 logs; p<0·001), completely prevented the development of SARS coronavirus-induced macroscopic lung pathology (p=0·013), and abolished shedding of virus in pharyngeal secretions. The data generated in this animal model show that administration of a human monoclonal antibody might offer a feasible and effective prophylaxis for the control of human SARS coronavirus infection.
Diagnostic electron microscopy (DEM) has conceptual predecessors â€" the application of the sense of vision and of light microscopy in medicine. The evolvement of DEM and the role of its two branches ...- histopathology and rapid negative-contrast DEM - are described in this review, with a focus on the latter. By its resolving power of 2 nm in praxi, DEM is able to visualize all kinds of pathogens, bacteria, parasites, even the smallest viruses. In contrast to other laboratory diagnostic methods, DEM excels by speed and "open view". All structures on the support grid can be assigned directly by "pattern recognition" of their fine structure to a specific family of agents. The morphology-based "catch-all" diagnosis can be decisive as a differential diagnosis and will help as a preliminary diagnosis to select and apply proper diagnostic tools for typing of the observed agent. Based on two case reports, the advantages and possible pitfalls of DEM are exemplified and hints are given to make DEM reliable and effective. Finally the role of DEM in medicine and the wider fields of life sciences are described together with the organizational conditions to guarantee its future in laboratory diagnostics.
Zusammenfassung
Hintergrund
Seit 1980 gelten die Pocken als ausgerottet. Es ist jedoch nicht auszuschließen, dass der Erreger der Pocken, das Variola-Virus, aus nicht vernichteten oder aus nach der ...Eradikation nicht an eines der beiden WHO-Referenzzentren (WHO Collaborating Smallpox Laboratories) abgegebenen Stämmen zu bioterroristischen Anschlägen genutzt wird. Aufgrund der Weiterentwicklung des molekularen Engineerings steigt zudem die Gefahr der Erzeugung neuer Pockenviren.
Ziel der Arbeit
Die Auswertung von klinischen und epidemiologischen Daten, aus denen Schlussfolgerungen für die Ausbruchskontrolle dieser lebensbedrohlichen Krankheit abgeleitet werden.
Methoden
Es handelt sich hier um eine Volltext-Handrecherche in den Hauptpublikationsorganen des öffentlichen Gesundheitswesens in Deutschland von 1945 bis 1975.
Ergebnis und Diskussion
Nach dem zweiten Weltkrieg ereigneten sich in Deutschland zwölf Pockenausbrüche, die hier hinsichtlich folgender Kenndaten ausgewertet werden: Beginn der Kontagiosität, Schutzwirkung der Impfung, Booster-Effekt bei der Wiederimpfung und Ansteckungsorte. Insgesamt erkrankten 95 Personen, von denen 10 verstarben. 81 der erkrankten Personen waren geimpft und entwickelten zu 91 % nur leichte Symptome. Leicht Erkrankte stellten nach primärer Fehldiagnose durch ihre weitere Teilnahme am öffentlichen Leben ein besonderes Risiko für die Weiterverbreitung des Erregers dar. Die hier dargestellten Daten zeigen ein niedriges Infektionsrisiko für die ersten drei Krankheitstage, wodurch antiepidemische Maßnahmen und die Kontaktverfolgung erleichtert werden. Die meisten Infektionen fanden im Krankenhaus statt, dies unterstreicht die Bedeutung einer guten Vorbereitung auch von peripheren Krankenhäusern. Die hier dargestellten Daten dokumentieren die Erfahrungen aus Deutschland und sollten zur Planung medizinischer und epidemiologischer Maßnahmen zur Ausbruchskontrolle hinzugezogen werden.
Bacteriophage Diversity in the North Sea WICHELS, A; BIEL, S. S; GELDERBLOM, H. R ...
Applied and Environmental Microbiology,
11/1998, Letnik:
64, Številka:
11
Journal Article
Serotyping of O-(lipopolysaccharide) and H-(flagellar) antigens is a wideley used method for identification of pathogenic strains and clones of Escherichia coli. At present, 176 O- and 53 H-antigens ...are described for E. coli which occur in different combinations in the strains. The flagellar antigen H4 is widely present in E. coli strains of different O-serotypes and pathotypes and we have investigated the genetic relationship between H4 encoding fliC genes by PCR, nucleotide sequencing and expression studies.
The complete nucleotide sequence of fliC genes present in E. coli reference strains U9-41 (O2:K1:H4) and P12b (O15:H17) was determined and both were found 99.3% (1043 of 1050 nucleotides) identical in their coding sequence. A PCR/RFLP protocol was developed for typing of fliC-H4 strains and 88 E. coli strains reacting with H4 antiserum were investigated. Nucleotide sequencing of complete fliC genes of six E. coli strains which were selected based on serum agglutination titers, fliC-PCR genotyping and reference data revealed 96.6 to 100% identity on the amino acid level. The functional expression of flagellin encoded by fliC-H4 from strain U9-41 and from our strain P12b which is an H4 expressing variant type was investigated in the E. coli K-12 strain JM109 which encodes flagellar type H48. The fliC recombinant plasmid carrying JM109 strains reacted with both H4 and H48 specific antisera whereas JM109 reacted only with the H48 antiserum. By immunoelectron microscopy, we could show that the flagella made by the fliC-H4 recombinant plasmid carrying strain are constituted of H48 and H4 flagellins which are co-assembled into functional flagella.
The flagellar serotype H4 is encoded by closely related fliC genes present in serologically different types of E. coli strains which were isolated at different time periods and geographical locations. Our expression studies show for the first time, that flagellins of different molecular weigh are functionally expressed and coassembled in the same flagellar filament in E. coli.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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