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1.
新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)疫情十分严重,给民众的健康带来了巨大威胁。COVID-19患者可能继发侵袭性真菌感染,会严重威胁患者的生命,因此,在诊治策略上应该给予重视。除了加强高危患者中病原真菌的常规检查外,还应加大力度支持和扶持病原真菌先进检测技术的研发;此外,还应重点支持针对医疗单位、公共场所和家庭等常温环境以及体表和器物表面灭活病毒、细菌、真菌等病原体的新型技术和方法的研发。最终为国家战胜COVID-19和继发感染疫情提供新措施和新策略。  相似文献   

2.
In 2012,a novel coronavirus,initially named as human coronavirus EMC(HCoV-EMC) but recently renamed as Middle East respiratory syndrome human coronavirus(MERS-CoV),was identified in patients who suffered severe acute respiratory infection and subsequent renal failure that resulted in death.Ongoing epidemiological investigations together with retrospective studies have found 61 laboratory-confirmed cases of infection with this novel coronavirus,including 34 deaths to date.This novel coronavirus is culturable and two complete genome sequences are now available.Furthermore,molecular detection and indirect immunofluorescence assay have been developed.The present paper summarises the limited recent advances of this novel human coronavirus,including its discovery,genomic characterisation and detection.  相似文献   

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The coronavirus disease 2019 (COVID-19) global pandemic evoked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered a major public health problem with significant morbidity and mortality. Understanding the pathogenesis and molecular mechanisms underlying this novel virus is crucial for both fundamental research and clinical trials in order to devise effective therapies and vaccination regimens. Basic research on SARS-CoV-2 largely depends on ex vivo models that allow viral invasion and replication. Organoid models are now emerging as a valuable tool to investigate viral biology and disease progression, serving as an efficient platform to investigate potential therapies for COVID-19. Here, we summarize various human stem cell-derived organoid types employed in SARS-CoV-2 studies. We highlight key findings from these models, including cell tropisms and molecular mechanisms in viral infection. We also describe their use in identifying potential therapeutic agents against SARS-CoV-2. As more and more advanced organoids emerge, they will facilitate the understanding of disease pathogenesis for drug development in this dreaded pandemic.  相似文献   

4.
Public health measures successfully contained outbreaks of the severe acute respiratory syndrome coronavirus (SARS-CoV) infection. However, the precursor of the SARS-CoV remains in its natural bat reservoir, and reemergence of a human-adapted SARS-like coronavirus remains a plausible public health concern. Vaccination is a major strategy for containing resurgence of SARS in humans, and a number of vaccine candidates have been tested in experimental animal models. We previously reported that antibody elicited by a SARS-CoV vaccine candidate based on recombinant full-length Spike-protein trimers potentiated infection of human B cell lines despite eliciting in vivo a neutralizing and protective immune response in rodents. These observations prompted us to investigate the mechanisms underlying antibody-dependent enhancement (ADE) of SARS-CoV infection in vitro. We demonstrate here that anti-Spike immune serum, while inhibiting viral entry in a permissive cell line, potentiated infection of immune cells by SARS-CoV Spike-pseudotyped lentiviral particles, as well as replication-competent SARS coronavirus. Antibody-mediated infection was dependent on Fcγ receptor II but did not use the endosomal/lysosomal pathway utilized by angiotensin I converting enzyme 2 (ACE2), the accepted receptor for SARS-CoV. This suggests that ADE of SARS-CoV utilizes a novel cell entry mechanism into immune cells. Different SARS vaccine candidates elicit sera that differ in their capacity to induce ADE in immune cells despite their comparable potency to neutralize infection in ACE2-bearing cells. Our results suggest a novel mechanism by which SARS-CoV can enter target cells and illustrate the potential pitfalls associated with immunization against it. These findings should prompt further investigations into SARS pathogenesis.  相似文献   

5.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel betacoronavirus, caused a pandemic leading to a standstill of nearly all global activities. There are some controversies on the production of specific immunoglobulin M (IgM) and IgG antibodies after the infection with SARS-CoV-2. This paper seeks to elaborate on the potential application of IgM and IgG antibodies and the viral antigens for the diagnosis and the course of the disease as well as the recurrence of positive nucleic acid tests after discharge.  相似文献   

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In this paper Bayesian approach is adopted to develop inferences about parameters in proportional odds models. Bayesian posterior intervals for coefficients in proportional odds models are derived by using approximation given in Pregibon (1981). The results are illustrated by using the lung cancer survival data reported by Prentice (1973).  相似文献   

8.
The novel coronavirus 2019-nCoV has caused the pandemic of Wuhan pneumonia recently, posing a serious threat to global public health, and thus calling for the development of therapeutics and prophylactics. Here we showed that high titer anti-SARS-CoV spike protein serum cannot effectively neutralize 2019-nCoV infection. Based on our previous research, we developed SARS pseudovirus (SARS-PsV) and MERS pseudovirus (MERS-PsV) as immunogens to immunize mice. We found sera from mice treated with SARS-CoV S protein could potently cross-neutralize infection by SARS-CoV (50% neutralizing antibody titers, NT50 > 40, 000) and SARS-related coronavirus (NT50 > 7, 000), but weakly for 2019-nCoV infection NT50 < 100), implying that it may not be practical to treat 2019-nCoV infection with anti-SARS-CoV antibodies and that people with history of SARS-CoV infection many years ago may not be resistant to 2019-nCoV infection.  相似文献   

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Dear Editor, The ongoing coronavirus disease 2019(COVID-19)global pandemic is caused by a novel coronavirus,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),which instigates severe and often fatal symptoms.As of September 4th,2020,more than 26 million cases of COVID-19 and almost 900,000 deaths have been reported to WHO.Based on Kissler and colleagues'modeled projections of future viral transmission scenarios,a resurgence in SARS-CoV-2 could occur over the next five years(Kissler et al.,2020).Research and clinical trials are underway to develop vacci-nes and treatments for COVID-19,but there are currently no specific vaccines or treatments for COVID-19(www.who.int),and therapeutic and prophylactic interventions are urgently needed to combat the outbreak of SARS-CoV-2.Of partic-ular importance is the identification of drugs which are effective,less-intrusive,most socioeconomic,and ready-to-use.  相似文献   

11.
Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is a novel virus that causes coronavirus disease 2019 (COVID-19). To understand the identity, functional characteristics and therapeutic targets of the virus and the diseases, appropriate infection models that recapitulate the in vivo pathophysiology of the viral infection are necessary. This article reviews the various infection models, including Vero cells, human cell lines, organoids, and animal models, and discusses their advantages and disadvantages. This knowledge will be helpful for establishing an efficient system for defense against emerging infectious diseases.  相似文献   

12.
In this paper, the fractional-order generalized Laguerre operational matrices (FGLOM) of fractional derivatives and fractional integration are derived. These operational matrices are used together with spectral tau method for solving linear fractional differential equations (FDEs) of order ν (0 < ν < 1) on the half line. An upper bound of the absolute errors is obtained for the approximate and exact solutions. Fractional-order generalized Laguerre pseudo-spectral approximation is investigated for solving nonlinear initial value problem of fractional order ν. The extension of the fractional-order generalized Laguerre pseudo-spectral method is given to solve systems of FDEs. We present the advantages of using the spectral schemes based on fractional-order generalized Laguerre functions and compare them with other methods. Several numerical examples are implemented for FDEs and systems of FDEs including linear and nonlinear terms. We demonstrate the high accuracy and the efficiency of the proposed techniques.  相似文献   

13.
The transport of charged particles across a strong magnetic field with a small random component is studied in the double diffusion approximation. It is shown that the density of the particles whose initial distribution is stretched along the field satisfies a subdiffusion equation with fractional derivatives. A more general initial particle distribution is also considered, and the applicability of the solutions obtained is discussed.  相似文献   

14.
Tetrapeptides derived from glycine and beta-alanine were hooked at the C-3beta position of the modified cholic acid to realize novel linear tetrapeptide-linked cholic acid derivatives. All the synthesized compounds were tested against a wide variety of microorganisms (gram-negative bacteria, gram-positive bacteria and fungi) and their cytotoxicity was evaluated against human embryonic kidney (HEK293) and human mammary adenocarcinoma (MCF-7) cell lines. While relatively inactive by themselves, these compounds interact synergistically with antibiotics such as fluconazole and erythromycin to inhibit growth of fungi and bacteria, respectively, at 1-24 microg/mL. The synergistic effect shown by our novel compounds is due to their inherent amphiphilicity. The fractional inhibitory concentrations reported are comparable to those reported for Polymyxin B derivatives.  相似文献   

15.
董慧君  李彤  庄辉  向宽辉 《微生物学报》2023,63(4):1329-1339
目前新型冠状病毒(severe acute respiratory syndrome coronavirus 2, SARS-CoV-2)感染所致的新型冠状病毒肺炎(corona virus disease, COVID-19)已成为威胁人类健康和安全的全球性流行性疾病。随着新突变株的不断出现,寻找有效治疗药物和靶点迫在眉睫。干扰素刺激基因(interferon-stimulated genes, ISGs)是由干扰素(interferons, IFNs)诱导后表达上调的一类基因,在宿主抵抗病毒感染过程中发挥着至关重要的作用。研究表明,ISGs能够靶向许多病毒复制的不同阶段发挥抗病毒作用,然而SARS-CoV-2也进化出各种策略干扰或逃避宿主天然免疫。因此,全面了解SARS-CoV-2与ISGs相互作用,对于设计抗病毒策略至关重要。本文简要综述不同ISGs抵抗SARS-CoV-2的作用机制,为开发新型的抗病毒药物提供思路和理论依据。  相似文献   

16.
主要研究了一类分数阶微分方程的最优控制问题.通过Oustaloup迭代逼近,可以将分数阶微分算子在频率域范围内进行近似.那么原先的分数阶微分方程就转换为一般的常微分方程.利用这个关系,可以得到关于分数阶微分方程的两个定理和一个引理.最后给出一个例子说明该方法的有效性.  相似文献   

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Summary HIV dynamics studies, based on differential equations, have significantly improved the knowledge on HIV infection. While first studies used simplified short‐term dynamic models, recent works considered more complex long‐term models combined with a global analysis of whole patient data based on nonlinear mixed models, increasing the accuracy of the HIV dynamic analysis. However statistical issues remain, given the complexity of the problem. We proposed to use the SAEM (stochastic approximation expectation‐maximization) algorithm, a powerful maximum likelihood estimation algorithm, to analyze simultaneously the HIV viral load decrease and the CD4 increase in patients using a long‐term HIV dynamic system. We applied the proposed methodology to the prospective COPHAR2–ANRS 111 trial. Very satisfactory results were obtained with a model with latent CD4 cells defined with five differential equations. One parameter was fixed, the 10 remaining parameters (eight with between‐patient variability) of this model were well estimated. We showed that the efficacy of nelfinavir was reduced compared to indinavir and lopinavir.  相似文献   

19.
A detailed analysis of a general class of SIRS epidemic models is given. Sufficient conditions are derived which guarantee the global stability of the endemic equilibrium solution. Further conditions are found which ensure instability for the equilibrium. Finally, the dependence of the stability on the contact number and the ratio of the mean length of infection to the mean removed time is considered.  相似文献   

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