Conserved amino acids W423 and N424 in receptor-binding domain of SARS-CoV are potential targets for therapeutic monoclonal antibody

The receptor-binding domain (RBD) on spike protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is the main region interacting with the viral receptor-ACE2 and is a useful target for induction of neutralizing antibodies against SARS-CoV infection. Here we generated two monoclonal antibodies (mAbs), targeting RBD, with marked virus neutralizing activity. The mAbs recognize a new conformational epitope which consists of several discontinuous peptides (aa. 343-367, 373-390 and 411-428) and is spatially located neighboring the receptor-binding motif (RPM) region of the RBD. Importantly, W423 and N424 residues are essential for mAb recognition and are highly conserved among 107 different strains of SARS, indicating that the residues are the most critical in the epitope which is a novel potential target for therapeutic mAbs. A human-mouse chimeric antibody, based upon the original murine mAb, was also constructed and shown to possess good neutralizing activity and high affinity.     

Role of Tyr306 in the C-terminal fragment of Clostridium perfringens enterotoxin for modulation of tight junction

We previously reported that the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE) is a novel type of absorption enhancer that interacts with claudin-4 and that Tyr306 of C-CPE plays a role in ability of C-CPE to modulate barrier of tight junctions. In the current study, to investigate effects of Tyr306 on the C-CPE activity, we prepared some C-CPE mutants substituted Tyr306 with Trp (Y306W), Phe (Y306F) and Lys (Y306K). We found that Y306W and Y306F mutants of C-CPE had claudin-4 binding affinities and effects on the barrier function of tight junctions, whereas both of these properties were greatly reduced with the Y306K mutant. Finally, the Y306K but not the Y306F and Y306W mutants had reduced abilities to enhance absorption in rat jejunum. These results indicate that aromatic and hydrophobic properties, not hydrogen bonding potential, of Tyr306 are involved in the interaction of C-CPE with claudin-4 and in the modulation of the tight junction barrier function by C-CPE.     

The Effectiveness of Commitment to Change Statements on Improving Practice Behaviors Following Continuing Pharmacy Education

Objectives

To determine the effectiveness of commitment to change (CTC) statements on behavior or practice change after a continuing pharmacy education (CPE) program, and to assess the percentage of CTC statements that are linked to program objectives.

Methods

Following a CPE program, 33 participants were asked to complete a CTC statement and describe changes that they planned on making in their behavior as preceptors. Six months later participants were asked to return the CTC statement and note the status of the change.

Results

Twenty-eight participants completed the CTC. Twenty-one (75%) participants returned the CTC statement 6 months later with a status report. Seventy percent of the 56 changes described by the 21 participants had been fully implemented. The majority of the changes (88%) matched program objectives.

Conclusion

Writing a CTC statement following completion of a CPE program may positively affect behavior change.     

Bovine lactoferrin digested with human gastrointestinal enzymes inhibits replication of human echovirus 5 in cell culture

Many infant formulas are enriched with lactoferrin (Lf) because of its claimed beneficial effects on health. Native bovine Lf (bLf) is known to inhibit in vitro replication of human enteroviruses, a group of pathogenic viruses that replicate in the gut as their primary infection site. On the basis of a model digestion and human gastrointestinal enzymes, we hypothesized that bLf could retain its antiviral properties against enterovirus in the gastrointestinal tract, either as an intact protein or through bioactive peptide fragments released by digestive enzymes. To test our hypothesis, bLf was digested with human gastric juice and duodenal juice in a 2-step in vitro digestion model. Two gastric pH levels and reduction conditions were used to simulate physiological conditions in adults and infants. The antiviral activity of native bLf and of the digested fractions was studied on echovirus 5 in vitro, using various assay conditions, addressing several mechanisms for replication inhibition. Both native and digested bLf fractions revealed a significant inhibitory effect, when added before or simultaneously with the virus onto the cells. Furthermore, a significant stronger sustained antiviral effect was observed when bLf was fully digested in the gastric phase with fast pH reduction to 2.5, compared with native bLf, suggesting the release of antiviral peptides from bLf during the human digestion process. In conclusion, this study demonstrates that bLf may have a role in the prevention of human gastrointestinal virus infection under physiological conditions and that food containing bLf may protect against infection in vivo.     

Nosocomial outbreak by NDM-1-producing Klebsiella pneumoniae highly resistant to cefiderocol,Florence, Italy,August 2021 to June 2022

A nosocomial outbreak by cefiderocol (FDC)-resistant NDM-1-producing Klebsiella pneumoniae (NDM-Kp) occurred in a large tertiary care hospital from August 2021–June 2022 in Florence, Italy, an area where NDM-Kp strains have become endemic. Retrospective analysis of NDM-Kp from cases observed in January 2021–June 2022 revealed that 21/52 were FDC-resistant. The outbreak was mostly sustained by clonal expansion of a mutant with inactivated cirA siderophore receptor gene, which exhibited high-level resistance to FDC (MIC ≥ 32 mg/L) and spread independently of FDC exposure.     

Multidrug-resistant organisms in patients from Ukraine in the Netherlands,March to August 2022

Since March 2022, there has been an emergence of multidrug-resistant organisms (MDRO) in the Netherlands in patients originating from Ukraine (58 patients, 75 isolates). For about half of these patients, recent hospitalisation in Ukraine was reported. Genomic surveillance revealed that the majority of the MDRO represent globally spread epidemic lineages and that 60% contain New Delhi metallo-β-lactamase (NDM) genes. Professionals should be aware of an increase in such MDRO associated with migration and medical evacuation of people from Ukraine.     

膦甲酸钠对九种病毒的体外抑制作用

本文观察了膦甲酸钠对人胚肾细胞、人胚肺二倍体细胞、Hep-2细胞及A549细胞等的细胞毒作用,结果表明本品对这些细胞毒性极小。在此基础上,根据国外有关文献报道,挑选了九种对膦甲酸钠敏感或不敏感的DNA病毒和RNA病毒,用病毒细胞病变抑制法,研究膦甲酸钠在体外对这些病毒的抑制作用,结果表明膦甲酸钠对HSV—1、HSV—2、CMV、EBV等疱疹类病毒具有明显的抑制作用,特别是对单纯疱疹病毒的作用最为显著,37.8～42μmol/ml即可抑制HSV和100个TCID_(50)的50%细胞病变。     

抗病毒无菌粉针剂抗病毒作用的研究

目的为明确抗病毒粉针剂体内外抗病毒谱及作用机制。方法采用组织细胞培养法、MTT染色法 ,检测抗病毒粉针剂对不同病毒株的作用 ,通过改变给药时间、途径 ,探讨抗病毒粉针剂抗病毒作用环节。通过建立病毒性流感动物模型 ,采用组织病理学检查法 ,观察抗病毒粉针剂对感染动物的保护作用。结果抗病毒粉针剂具有明显的抗流感病毒、呼吸道合胞病毒、腺病毒的作用 ,抗病毒作用是多途径的。结论抗病毒粉针剂是一个较广谱的抗呼吸道病毒针剂     

Isolation of Coxsackievirus A24 variant from patients with hemorrhagic conjunctivitis in Cuba, 2008-2009

Background

An outbreak of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009.

Objective

To determinate the etiological agent associated with the Cuban outbreaks of acute hemorrhagic conjunctivitis during 2008 and 2009.

Study design

Conjunctival swabs and/or faecal samples from 382 patients with clinical diagnosis suggestive of acute hemorrhagic conjunctivitis were subject to viral culture in HEp-2 human laryngeal epidermoid carcinoma cells. Positive samples were identified by a specific Coxsackievirus A24 variant PCR and the 3C protease region of 16 isolates was sequenced for phylogenetic analysis.

Results

Enterovirus cytopathic effect was observed in 138 cases (36%). A higher percent of CA24v was recovered from faecal samples, 19 out of 45 cases (42.2%), than from conjunctival swabs, 127 out of 355 samples (35.8%). All isolates were identified as Coxsackievirus A24 variant. Phylogenetic analysis revealed that 2008 and 2009 Cuban outbreaks were caused by the same virus strains and that isolates were closely related to those from Taiwan (2006-2007), China (2007-2008) and Singapore (2005) with a bootstrap value of 71%.

Conclusions

Outbreaks of acute hemorrhagic conjunctivitis occurred in Cuba in 2008 and 2009 were caused by Coxsackievirus A24 variant. The faecal-oral route is another mode of transmission of CA24v in the acute hemorrhagic conjunctivitis outbreaks. Phylogenetic analysis of Cuban CA24v strains involved in an acute hemorrhagic conjunctivitis outbreak in 2008 and 2009 confirms a new introduction of the CA24 variant into the Americas from South-east Asia.