Inhibitory effects of tricin derivative from Sasa albo-marginata on replication of human cytomegalovirus

The anti-human cytomegalovirus (HCMV) activity of tricin (4′,5,7-trihydroxy-3′,5′-dimethoxyflavone), a derivative from Sasa albo-marginata, was studied in the human embryonic fibroblast cell line MRC-5. In a plaque assay, tricin and ganciclovir (GCV) showed concentration-dependent inhibitory properties from 0.05 to 3.6 μM and 0.01 to 1.0 μM, respectively. Tricin had no virucidal effects on cell-free HCMV. Treatment with tricin 1 h before, or 1 h or 3 h after viral infection significantly suppressed HCMV replication. Moreover, tricin inhibited the expression of immediate early (IE) 2 mRNA and DNA polymerase (UL54) mRNA in HCMV-infected cells. Western blot analysis also demonstrated that tricin decreased the expression of IE antigen (especially IE2) and cyclooxygenase 2 (COX-2) expression in HCMV-infected cells. In the presence of tricin, prostaglandin E2 (PGE₂) accumulation by HCMV infection was completely inhibited. These results suggest that tricin is a novel compound with potential COX inhibitor-dependent anti-HCMV activity.     

婴幼儿人巨细胞病毒mRNA在不同感染时期表达的研究

【摘要】目的 探讨IE mRNA和pp67mRNA是否可以作为早期检测诊断人巨细胞病毒（HCMV）感染的标志物。 方法 采用荧光定量PCR的方法,在HCMV感染初诊患儿中检测IE mRNA和pp67mRNA的表达特征。结果 传统病毒DNA检测方法检测的阴性患儿中,仍然有一部分已经表达IE mRNA,而在初诊病毒DNA检测阳性的患儿中,100%表达HCMV感染后期的pp67mRNA。结论 mRNA检测具有比DNA更高的灵敏性,应该根据不同时期病毒mRNA表达特征制定不同的治疗方案。     

更昔洛韦治疗幼儿感染人巨细胞病毒的预后评估指标的探讨

【摘要】目的 探讨IE mRNA 和pp67 mRNA 在更昔洛韦治疗后的人巨细胞病毒（HCMV）感染患儿中的表达情况。方法 在接受更昔洛韦治疗前,治疗2 周和停药4 周时检测HCMV 患儿总胆红素（TBIL）、直接胆红素（DBIL）;丙氨酸转氨酶（ALT）、碱性磷酸酶（ALP）及荧光定量PCR 的方法检测HCMV-DNA 拷贝数,IE mRNA 和 pp67 mRNA 的表达采用实时荧光定量PCR 法进行检测。结果 更昔洛韦治疗2 周后,患儿肝功能及血HCMVDNA 均较治疗前降低,停药4 周后TBIL、DBIL、ALT、ALP 及HCMV-DNA 拷贝数均较治疗前显著降低,但是与治疗 2 周比较差异无统计学意义。治疗后2 周,仍有12 例患儿血液中表达pp67 mRNA,表达量显著低于治疗前的pp67 mRNA 表达量,但检测不到患儿表达IE mRNA。停药4 周,pp67 mRNA 阳性表达的患儿数量显著低于治疗2 周的患儿数量,有3 例患儿表达微弱的IE mRNA。2 个基因的mRNA 表达量与治疗2 周比较差异无统计学意义。结论 在更昔洛韦治愈患儿,HCMV-DNA 检测呈现阴性时,应再进行病毒mRNA 检测,对RNA 表达阳性的患儿,应该加强随访与复查,预防病毒复发。     

Differential adhesion-inhibitory patterns of antibodies raised against two major variants of the NTS-DBL2X region of VAR2CSA

Background

VAR2CSA is a large polymorphic Plasmodium falciparum protein expressed on infected erythrocytes (IE) that allows their binding in the placenta, thus precipitating placental malaria (PM). The N-terminal part of VAR2CSA that contains the binding site to placental chondroitin sulfate A (CSA) is currently recognized as the most attractive region for vaccine development. An ultimate challenge is to define epitopes in this region that induce a broad cross-reactive adhesion inhibitory antibody response.

Methods

Based on phylogenetic data that identified a dimorphic sequence motif in the VAR2CSA DBL2X, we raised antibodies against the NTS-DBL2X constructs containing one sequence or the other (3D7 and FCR3) and tested their functional properties on P. falciparum isolates from pregnant women and on laboratory-adapted strains.

Results

The CSA binding inhibitory capacity of the antibodies induced varied from one parasite isolate to another (range, 10%–100%), but the combined analysis of individual activity highlighted a broader functionality that increased the total number of isolates inhibited. Interestingly, the differential inhibitory effect of the antibodies observed on field isolates resulted in significant inhibition of all field isolates tested, suggesting that optimal inhibitory spectrum on field isolates from pregnant women might be achieved with antibodies targeting limited variants of the N-terminal VAR2CSA.

Conclusions

Our findings indicate that the NTS-DBL2X region of VAR2CSA can elicit strain-transcending anti-adhesion antibodies and suggest that the combination of the two major variants used here could represent the basis for an effective bivalent VAR2CSA-based vaccine.     

Two weeks of postsurgical therapy may be enough for high-risk cases of endocarditis caused by Streptococcus viridans or Streptococcus bovis

The duration of antimicrobial therapy after surgery for infective endocarditis (IE) is controversial. A short course of postsurgical therapy is currently accepted only for patients with negative valve culture. We performed a retrospective (1994–2008) analysis of patients who underwent surgery for IE in our hospital and had a high risk of complications (one of more of the following: <2 weeks of antibiotic treatment before surgery; embolism; perivalvular extension; and positive valve culture) to compare outcomes of patients who received short-course antimicrobial therapy (SAT) (median 15 days) or long-course antimicrobial therapy (LAT) (median 32 days), irrespective of the results of valve culture. Our endpoints included length of hospital stay, renal and hepatic failure, relapse, re-infection, and mortality rates 1 year after surgery. During the study period, 140 patients underwent surgery for IE (valve replacement, 87.9%). Of these, 133 fulfilled the high-risk group criteria and 92 completed the antimicrobial schedule. Comparison of patients receiving SAT (37) and LAT (55) showed that the SAT group had a shorter length of hospital stay (29 vs. 40 days, p 0.01), and a trend towards lower frequency of renal failure (5.4% vs. 18.2%, p 0.11) and hepatic failure (5.4% vs. 9.1%, p 0.69), whereas mortality (5.4% vs. 3.6%, p 1), relapse (0% vs. 1.8%, p 1) and re-infection (5.4% vs. 3.6%, p 1) rates were similar between both groups. Multivariate analysis showed that IE caused by Streptococcus viridans or Streptococcus bovis was independently associated with SAT. Postsurgical SAT is safe, especially when IE is caused by Streptococcus viridans or Streptococcus bovis, even in patients at high risk of complications.     

Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition

Human cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2-11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein still recognized and lysed mutant virus infected fibroblasts. Yet, suppression of IE1 derived peptide presentation by gpUS2 or gpUS11 was far more pronounced. The results show that gpUS2 and gpUS11 alone only incompletely protect HCMV infected fibroblasts from CTL recognition and underline the importance of studying infected cells to elucidate HCMV immune evasion.     

Transthoracic Echocardiography Is Still Useful in the Initial Evaluation of Patients With Suspected Infective Endocarditis: Evaluation of a Large Cohort at a Tertiary Referral Center

ObjectivesTo examine the sensitivity of contemporary transthoracic echocardiography (TTE) for the detection of vegetation, abscess cavity, or prosthetic valve dehiscence (Vg) in patients with suspected infective endocarditis (IE) and to identify whether a relatively normal initial TTE finding can be effectively used as a rule out test, obviating the need for transesophageal echocardiography (TEE).Patients and MethodsWe evaluated clinical, microbiological, and echocardiographic data for all patients with suspected IE referred for both TTE and TEE between January 1, 2005, and December 31, 2010. Patients were stratified into 3 groups by baseline TTE findings: negative TTE (native valves with less than or equal to mild regurgitation and no Vg), equivocal TTE (no Vg but prosthetic valve or greater than mild native valvular regurgitation), and positive TTE (Vg detected).ResultsWe studied 622 consecutive patients (68% male; mean ± SD age, 62±17 years), including 256 with Staphylococcus aureus bacteremia (SAB). The presence of Vg was confirmed by TEE in 141 patients (23%). The TTE had low sensitivity for the detection of Vg (58%). A total of 271 patients (44%) had an initial negative TTE. Of these, TEE demonstrated Vg in only 8 patients (negative predictive value [NPV] of negative TTE, 97%). The negative TTE group included 132 patients with SAB, only 6 of whom had Vg (NPV, 95%). Of 265 patients with equivocal TTE, Vg was demonstrated in 51 (19%).ConclusionIn a hospital population with clinically suspected IE, TTE had low sensitivity for the detection of Vg; however, a negative initial TTE was a common finding, with a high NPV, even in the setting of SAB. A TEE may be avoided in many patients with suspected IE.     

Clinical Outcomes of Infective Endocarditis in Injection Drug Users

Background

Rising rates of hospitalization for infective endocarditis (IE) have been increasingly tied to rising injection drug use (IDU) associated with the opioid epidemic.