AIM: To analyze outcomes of delayed single-stage necrosectomy after early conservative management of patients with infected pancreatic necrosis (IPN) associated with severe acute pancreatitis (SAP). METHODS: Between J...AIM: To analyze outcomes of delayed single-stage necrosectomy after early conservative management of patients with infected pancreatic necrosis (IPN) associated with severe acute pancreatitis (SAP). METHODS: Between January 1998 and December 2009, data from patients with SAP who developed IPN and were managed by pancreatic necrosectomy were analyzed. RESULTS: Fifty-nine of 61 pancreatic necrosectomies were performed by open surgery and 2 laparoscopically. In 55 patients, single-stage necrosectomy could be performed (90.2%). Patients underwent surgery at a median of 29 d (range 13-46 d) after diagnosis of acute pancreatitis. Sepsis and multiple organ failure accounted for the 9.8% mortality rate. Pancreatic fistulae (50.8%) predominantly accounted for the morbidity. The median hospital stay was 23 d, and the median interval for return to regular activities was 110 d.CONCLUSION: This series supports the concept of delayed single-stage open pancreatic necrosectomy for IPN. Advances in critical care, antibiotics and interventional radiology have played complementary role in improving the outcomes.展开更多
In this paper, a diffusive hepatitis B virus （HBV） infection model with a discrete time delay is presented and analyzed, where the spatial mobility of both intracellular capsid covered HBV DNA and HBV and the intrac...In this paper, a diffusive hepatitis B virus （HBV） infection model with a discrete time delay is presented and analyzed, where the spatial mobility of both intracellular capsid covered HBV DNA and HBV and the intracellular delay in the reproduction of infected hepatocytes are taken into account. We define the basic reproduction number R0 that determines the dynamical behavior of the model. The local and global stability of the spatially homogeneous steady states are analyzed by using the linearization technique and the direct Lyapunov method, respectively. It is shown that the susceptible uninfected steady state is globally asymptotically stable whenever R0 ≤i and is unstable whenever R0 〉1. Also, the infected steady state is globally asymptotically stable when R0 〉 1. Finally, numerical simulations are carried out to illustrate the results obtained.展开更多
Oxidative stress, regarded as a negative effect of free radicals in vivo, takes place when organisms suffer from harmful stimuli. Some viruses can induce the release of reactive oxygen species （ROS） in infected cell...Oxidative stress, regarded as a negative effect of free radicals in vivo, takes place when organisms suffer from harmful stimuli. Some viruses can induce the release of reactive oxygen species （ROS） in infected cells, which may be closely related with their pathogenicity. In this report, chaetocin, a fimgal metabolite reported to have antimicrobial and cytostatic activity, was studied for its effect on the activation of latent Epstein-Barr virus （EBV） in B95-8 cells. We found that chaetocin remarkably up-regulated EBV lytic transcription and DNA replication at a low concentration （50 nmol L-l）. The activation of latent EBV was accompanied by an increased cellular ROS level. N-acetyl-L-cysteine （NAC）, an ROS inhibitor, suppressed chaetocin-induced EBV activation. Chaetocin had little effect on histone H3K9 methylation, while NAC also significantly reduced H3K9 methylation. These results suggested that chaetocin reactivates latent EBV primarily via ROS pathways.展开更多
In this paper, following a previous paper （[32] Permanence and extinction of a non- autonomous HIV-I model with two time delays, preprint） on the permanence and extinc- tion of a delayed non-autonomous HIV-1 within-...In this paper, following a previous paper （[32] Permanence and extinction of a non- autonomous HIV-I model with two time delays, preprint） on the permanence and extinc- tion of a delayed non-autonomous HIV-1 within-host model, we introduce and investigate a delayed HIV-1 model including maximum homeostatic proliferation rate of CD4＋ T- cells and varying coefficients. By applying the asymptotic analysis theory and oscillation theory, we show： （i） the system will be permanent when the threshold value R. 〉 1, and for this case we also obtain the explicit estimate of the eventual lower bound of the HIV-1 virus load; （ii） the threshold value R＊ 〈 1 implies the extinction of the virus. Furthermore, we obtain that the threshold dynamics is in agreement with that of the corresponding autonomous system, which extends the classic results for the system with constant coefficients. Numerical simulations are also given to illustrate our main results, and in particular, some sensitivity test of R. is established.展开更多
In this paper, a HTLV-I infection model with two delays is considered. It is found that the dynamics of this model are determined by two threshold parameters R0 and R1, basic reproduction numbers for viral infection a...In this paper, a HTLV-I infection model with two delays is considered. It is found that the dynamics of this model are determined by two threshold parameters R0 and R1, basic reproduction numbers for viral infection and for CTL response, respectively. If R0 〈 1, the infection-free equilibrium P0 is globally asymptotically stable. If R1 〈 1 〈 R0, the asymptomatic-carrier equilibrium P1 is globally asymptotically stable. If R1 〉 1, there exists a unique HAM/TSP equilibrium P2. The stability of P2 is changed when the second delay T2 varies, that is there exist stability switches for P2.展开更多
The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s mod...The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s model with two definitive hosts and define basic reproductive number. The stability of equilibria for the systems with and without time delays are both investigated. To study the impact of the latent periods on the transmission of schistosomiasis, some sensitivity analysis of the basic reproductive number on the three time delays are carried out. It is shown that the basic reproductive number decreases as the three time delays increase. Furthermore, the impact of the latent periods of infected snails on the system is stronger than that of the latent periods of infected human and infected bovines. Thus, to reduce the prevalence of schistosomiasis infection, prolonging the latent periods of infected snails by some measures could achieve better results than prolonging the latent periods of infected definitive hosts.展开更多
文摘AIM: To analyze outcomes of delayed single-stage necrosectomy after early conservative management of patients with infected pancreatic necrosis (IPN) associated with severe acute pancreatitis (SAP). METHODS: Between January 1998 and December 2009, data from patients with SAP who developed IPN and were managed by pancreatic necrosectomy were analyzed. RESULTS: Fifty-nine of 61 pancreatic necrosectomies were performed by open surgery and 2 laparoscopically. In 55 patients, single-stage necrosectomy could be performed (90.2%). Patients underwent surgery at a median of 29 d (range 13-46 d) after diagnosis of acute pancreatitis. Sepsis and multiple organ failure accounted for the 9.8% mortality rate. Pancreatic fistulae (50.8%) predominantly accounted for the morbidity. The median hospital stay was 23 d, and the median interval for return to regular activities was 110 d.CONCLUSION: This series supports the concept of delayed single-stage open pancreatic necrosectomy for IPN. Advances in critical care, antibiotics and interventional radiology have played complementary role in improving the outcomes.
文摘In this paper, a diffusive hepatitis B virus （HBV） infection model with a discrete time delay is presented and analyzed, where the spatial mobility of both intracellular capsid covered HBV DNA and HBV and the intracellular delay in the reproduction of infected hepatocytes are taken into account. We define the basic reproduction number R0 that determines the dynamical behavior of the model. The local and global stability of the spatially homogeneous steady states are analyzed by using the linearization technique and the direct Lyapunov method, respectively. It is shown that the susceptible uninfected steady state is globally asymptotically stable whenever R0 ≤i and is unstable whenever R0 〉1. Also, the infected steady state is globally asymptotically stable when R0 〉 1. Finally, numerical simulations are carried out to illustrate the results obtained.
文摘Oxidative stress, regarded as a negative effect of free radicals in vivo, takes place when organisms suffer from harmful stimuli. Some viruses can induce the release of reactive oxygen species （ROS） in infected cells, which may be closely related with their pathogenicity. In this report, chaetocin, a fimgal metabolite reported to have antimicrobial and cytostatic activity, was studied for its effect on the activation of latent Epstein-Barr virus （EBV） in B95-8 cells. We found that chaetocin remarkably up-regulated EBV lytic transcription and DNA replication at a low concentration （50 nmol L-l）. The activation of latent EBV was accompanied by an increased cellular ROS level. N-acetyl-L-cysteine （NAC）, an ROS inhibitor, suppressed chaetocin-induced EBV activation. Chaetocin had little effect on histone H3K9 methylation, while NAC also significantly reduced H3K9 methylation. These results suggested that chaetocin reactivates latent EBV primarily via ROS pathways.
文摘In this paper, following a previous paper （[32] Permanence and extinction of a non- autonomous HIV-I model with two time delays, preprint） on the permanence and extinc- tion of a delayed non-autonomous HIV-1 within-host model, we introduce and investigate a delayed HIV-1 model including maximum homeostatic proliferation rate of CD4＋ T- cells and varying coefficients. By applying the asymptotic analysis theory and oscillation theory, we show： （i） the system will be permanent when the threshold value R. 〉 1, and for this case we also obtain the explicit estimate of the eventual lower bound of the HIV-1 virus load; （ii） the threshold value R＊ 〈 1 implies the extinction of the virus. Furthermore, we obtain that the threshold dynamics is in agreement with that of the corresponding autonomous system, which extends the classic results for the system with constant coefficients. Numerical simulations are also given to illustrate our main results, and in particular, some sensitivity test of R. is established.
基金Acknowledgments The authors would like to thank the reviewers＇ constructive suggestions which have improved the presentation of the paper. This research is supported by National Natural Science Foundation of China （No. 11371111）, the Research Fund for the Doctoral Program of Higher Education of China （No. 20122302110044） and Shandong Provincial Natural Science Foundation, China （No. ZR2013AQ023）.
文摘In this paper, a HTLV-I infection model with two delays is considered. It is found that the dynamics of this model are determined by two threshold parameters R0 and R1, basic reproduction numbers for viral infection and for CTL response, respectively. If R0 〈 1, the infection-free equilibrium P0 is globally asymptotically stable. If R1 〈 1 〈 R0, the asymptomatic-carrier equilibrium P1 is globally asymptotically stable. If R1 〉 1, there exists a unique HAM/TSP equilibrium P2. The stability of P2 is changed when the second delay T2 varies, that is there exist stability switches for P2.
文摘The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s model with two definitive hosts and define basic reproductive number. The stability of equilibria for the systems with and without time delays are both investigated. To study the impact of the latent periods on the transmission of schistosomiasis, some sensitivity analysis of the basic reproductive number on the three time delays are carried out. It is shown that the basic reproductive number decreases as the three time delays increase. Furthermore, the impact of the latent periods of infected snails on the system is stronger than that of the latent periods of infected human and infected bovines. Thus, to reduce the prevalence of schistosomiasis infection, prolonging the latent periods of infected snails by some measures could achieve better results than prolonging the latent periods of infected definitive hosts.
