Molecular epidemiology of respiratory syncytial virus infections in chidren between 2002 and 2006

Hintergrund: Infektionen mit dem Respiratory Syncytial Virus (RSV) sind die häufigste virale Ursache für respiratorische Erkrankungen bei Säuglingen und Kleinkindern. Reinfektionen treten lebenslang auf. Es wurden zwei Typen (A und B) und mehrere Genotypen beschrieben. Die vorliegenden Daten über die molekulare Epidemiologie von RSV in Deutschland sind nur begrenzt. Material und Methoden: Zwischen Januar 2002 und Juli 2006 wurden 221 Nasenrachensekrete (NRS) von Kindern, welche in der Universitätskinderklinik Würzburg behandelt wurden, durch Routine-Untersuchung mit einem Immunfluoreszenztest auf RSV-Antigen positiv befunden. Die phylogenetische Analyse wurde aus Restmaterial von 211 NRS durchgeführt, indem die zweite variable Region des G-Gens amplifiziert und sequenziert wurde. Ergebnisse: Insgesamt war die Prävalenz von Typ A-Viren mit 69,5 % größer als die der Typ B-Viren mit 30,5 %. RSV Typ A war das dominierende Virus in allen Saisons außer in der Saison 2002-2003. Über den gesamten Beobachtungszeitraum traten drei A-Genotypen (GA2, GA5 und GA7) und vier B-Genotypen (GB3, SAB3, BA und ein neuer Genotyp) auf. Die Genotypen GA2, GA5, SAB3 und BA waren am häufigsten im Umlauf und in beinahe allen Saisons prävalent. Unter den B-Genotypen nahm der Anteil des Genotyps BA von 25 % (2002) auf 92 % (2005-2006) zu. Drei Typ B-Sequenzen wurden einem neuen Genotyp zugeordnet, welcher BWUE benannt wurde. Es wurde eine Reinfektion mit demselben Genotyp (GA5) bei einem Kind beobachtet, welches im Alter von 12 und 28 Monaten mit einer RSV-Infektion hospitalisiert war. Schlußfolgerung: Die Ergebnisse unserer Studie stehen in Einklang mit der molekularen Epidemiologie von RSV in anderen geographischen Regionen. Wir beobachteten sowohl Genotypen, welche über mehrere Saisons prävalent waren, als auch Genotypen, welche über den beobachteten Zeitraum zunehmend dominanter werdend andere Genotypen verdrängten. Zudem wurde ein neuer B-Genotyp entdeckt.Title: Molecular epidemiology of respiratory syncytial virus infections in Underfranconia between 2002 and 2006 Background: The respiratory syncytial virus (RSV) es the most common viral cause of respiratory infections in infants and children. Reinfections occur lifelong. Two RSV subtypes (A and B) and several genotypes have been described. The available data on the molecular epidemiology of RSV in Germany are only limited. Material and methods: Between January 2002 and July 2006, 211 respiratory samples of infants and children treated in the Children’s Hospital of the University Würzburg were found to be positive for RSV antigen by routine testing with immunofluorescensce assays. Phylogenetic analysis was performed on 211 of these samples by amplification and sequencing of the second variable region of the RSV G gene. Results: The type distribution of the 211 RSV positive samples was 69,5 % type A and 30,5 % type B. RSV type A was the predominating virus in all seasons except for the winter season 2002/03. Over the whole observation period, three different A-genotypes (GA2, GA5, GA7) and four different B-genotypes (GB3, SAB3, BA and novel genotype) were detected. The RSV genotypes GA2, GA5, SAB3 and BA were most frequently found and were prevalent in almost all seasons. Among the B-genotypes, the proportion of the genotype BA increased from 25 % in 2002 to 91 % in 2005/06. Three type B sequences were assigned to a novel genotype, which was tentatively named BWUE. One reinfection with the same genotype (GA5) was observed in a child who was hospitalised with RSV infection at the age of 12 and 28 months. Conclusion: The results of our study are in agreement with the molecular epidemiology of RSV in other geographical regions. We observed both genotype persistence and genotype shifting during the observation period. In addition, we detected a novel B genotype

Evaluation of suspected malignant hyperthermia events during anesthesia

Background Malignant hyperthermia (MH), a metabolic myopathy triggered by volatile anesthetics and depolarizing muscle relaxants, is a potentially lethal complication of general anesthesia in susceptible patients. The implementation of modern inhalation anesthetics that research indicates as less potent trigger substances and the recommended limitations of succinylcholine use, suggests there may be considerable decline of fulminant MH cases. In the presented study, the authors analyzed suspected MH episodes during general anesthesia of patients that were referred to the Wuerzburg MH unit between 2007 and 2011, assuming that MH is still a relevant anesthetic problem in our days. Methods With approval of the local ethics committee data of patients that underwent muscle biopsy and in vitro contracture test (IVCT) between 2007 and 2011 were analyzed. Only patients with a history of suspected MH crisis were included in the study. The incidents were evaluated retrospectively using anesthetic documentation and medical records. Results Between 2007 and 2011 a total of 124 patients were tested. 19 of them were referred because of suspected MH events; 7 patients were diagnosed MH-susceptible, 4 MH-equivocal and 8 MH-non-susceptible by IVCT. In a majority of cases masseter spasm after succinylcholine had been the primary symptom. Cardiac arrhythmias and hypercapnia frequently occurred early in the course of events. Interestingly, dantrolene treatment was initiated in a few cases only. Conclusions MH is still an important anesthetic complication. Every anesthetist must be aware of this life-threatening syndrome at any time. The rapid onset of adequate therapy is crucial to avoid major harm and possibly lethal outcome. Dantrolene must be readily available wherever MH triggering agents are used for anesthesia

Functional characterization of the RYR1 mutation p.Arg4737Trp associated with susceptibility to malignant hyperthermia

Aside from the in vitro contracture test, genetic screening for causative RYR1 mutations is the established procedure to diagnose susceptibility to malignant hyperthermia (MH). However, currently only 34 out of more than 300 known RYR1 mutations have been confirmed to be causative for MH by experimental studies addressing their functional impact on intracellular calcium homeostasis. The RYR1 mutation p.Arg4737Trp has been recently detected in a German MH family. To evaluate the effects of that mutation on intracellular calcium handling, the response after stimulation with the RYR1 agonist 4-chloro-m-cresol was investigated in immortalized B lymphocytes containing the p.Arg4737Trp mutation and compared to the response of wild type RYR1 from unaffected family members and unrelated controls. Intracellular resting calcium was slightly but significantly elevated in mutation positive cells. Calcium release following stimulation with 4-chloro-m-cresol was significantly increased in B lymphocytes carrying the p.Arg4737Trp mutation compared to mutation negative controls. Hence, the functional properties of the RYR1 mutation p.Arg4737Trp are consistent with susceptibility to MH Together with previously published data, the mutation has now been reported in three independent MH positive families