Drug delivery systems (DDSs) based on nanomaterials have shown a promise for cancer chemotherapy; however, it remains a great challenge to localize on-demand release of anticancer drugs in tumor tissues to improve therapeutic effects and minimize the side effects. In this regard, photoresponsive DDSs that employ light as an external stimulus can offer a precise spatiotemporal control of drug release at desired sites of interest. Most photoresponsive DDSs are only responsive to ultraviolet-visible light that shows phototoxicity and/or shallow tissue penetration depth, and thereby their applications are greatly restricted. To address these issues, near-infrared (NIR) photoresponsive DDSs have been developed. In this review, the development of NIR photoresponsive DDSs in last several years for cancer photo-chemotherapy are summarized. They can achieve on-demand release of drugs into tumors of living animals through photothermal, photodynamic, and photoconversion mechanisms, affording obviously amplified therapeutic effects in synergy with phototherapy. Finally, the existing challenges and further perspectives on the development of NIR photoresponsive DDSs and their clinical translation are discussed.
Background
Norovirus (NoV) is recognized as a leading cause of acute gastroenteritis (AGE) outbreaks in settings globally. Studies have shown that employees played an important role in the transmission mode during some NoV outbreaks. This study aimed to investigate the prevalence of NoV infection and duration of NoV shedding among employees during NoV outbreaks, as well as factors affecting shedding duration.
Methods
Specimens and epidemiological data were collected from employees who were suspected of being involved in the transmission or with AGE symptoms during NoV outbreaks in Xuhui District, Shanghai, from 2015 to 2017. Specimens were detected using real-time RT-PCR to determine whether or not employees had become infected with NoV. Specimens were collected every 3–7 days from NoV-infected employees until specimens became negative for NoV.
Results
A total of 421 employees were sampled from 49 NoV outbreaks, and nearly 90% of them (377/421) were asymptomatic. Symptomatic employees showed significantly higher prevalence of NoV infection than asymptomatic ones (70.5% vs. 17.0%,
P
< 0.01). The average duration of NoV shedding was 6.9 days (95% confidence interval: 6.1–7.7 days) among 88 NoV-infected individuals, and was significantly longer in symptomatic individuals than in asymptomatic ones (9.8 days vs. 5.6 days,
P
< 0.01). In Cox proportional-hazards model, after adjusting age and gender, symptoms was the only factor associated with duration of NoV shedding.
Conclusions
Compared with asymptomatic employees, symptomatic employees had higher prevalence of NoV infection and longer durations of NoV shedding. Since NoV shedding duration among NoV-infected employees tends to be longer than their isolation time during outbreaks, reinforcement of hygiene practices among these employees is especially necessary to reduce the risk of virus secondary transmissions after their return to work.
To investigate varicella outbreak trends among schoolchildren during the voluntary singledose varicella vaccine (VarV) era in Shanghai, China. Methods: Trends in school varicella outbreaks from 2006 to 2017 were assessed using joinpoint regression models. The impacts of changes in single-dose VarV coverage among schoolchildren and implementation of post-exposure prophylaxis (PEP) strategies on outbreak trends were further analyzed. Results: In total, 265 varicella outbreaks involving 3263 cases were reported in Shanghai from 2006 to 2017. The number of outbreaks showed an increasing trend from 2006 to 2017 (t = 2.62, p = 0.026), especially in kindergartens. The proportion of breakthrough varicella cases among all outbreak-related cases showed an increasing trend from 30.4% in 2008 to 85.7% in 2017 (t = 7.45, p < 0.001). Single-dose VarV coverage among schoolchildren was 88.1%, and showed a significant increase from the 1996 to the 2008 birth cohorts, followed by a non-significant decline from the 2008 to the 2014 birth cohorts. During school outbreaks in which PEP campaigns were conducted, the varicella attack rate was significantly lower than those in outbreaks without PEP campaigns (1.2% vs. 1.4%; Chi-square = 23.35, p < 0.001). Conclusions: Even with high coverage, single-dose VarV is insufficient to prevent school outbreaks. The administration of VarV as PEP is an appropriate intervention for varicella outbreak control prior to implementing a two-dose VarV schedule.
Background: Recurring outbreaks of infectious diseases highlight the importance of population vaccination strategies. We aimed to assess the impact of national vaccination strategies on vaccine-preventable infectious diseases (VPDs) in Shanghai, China and to identify vulnerable groups that may benefit from future vaccination policies.Methods: Infectious disease data from 1953 to 2018 was obtained from Xuhui District Center for Disease Control and Prevention, Shanghai China. We used joinpoint regression to show incidence, mortality and fatality trends and to determine annual percent change in incidence of 12 VPDs among three eras of national immunization strategies:
INTRODUCTION
The Smoking Control Regulation in Public Places (hereafter, the ‘regulations’) has been implemented in Shanghai since 2010. This study explores the changes in smoking prevalence and its influencing factors among urban Shanghai residents.
METHODS
Two rounds of household investigations (the Health Status and Health Service Utilization Survey) were carried out using a multistage probability proportionate-to-size sampling method in an urbanized district in 2010 and 2015. Descriptive and logistic regression analyses were applied to the statistics.
RESULTS
From 2010 to 2015, the standardized current smoking rate fell from 24.8% to 19.1% (38.3% to 32.0% among men, and 1.9% to 1.4% among women). Meanwhile, the standardized smoking cessation rate increased from 18.1% to 23.3%. Smoking prevalence in respondents aged 45 to 59 years was still higher than that of other age groups. Changes in smoking prevalence and cessation rates were more obvious in respondents aged 30–44 and over 75 years. Sex, age, education, marital status, and alcohol use were influencing factors of current smoking, while sex, age and alcohol use were influencing factors of smoking cessation.
CONCLUSIONS
The implementation of smoking control regulations may be beneficial for reducing smoking and increasing smoking cessation, especially among middle-aged and older men. Nevertheless, tobacco control in urban Shanghai still faces huge challenges. Therefore, more targeted and comprehensive measures should be taken.
Objectives: Although administration of a second dose of varicella vaccine (2 nd -dose VarV) to individuals who have previously received one-dose VarV has been recommended as a post-exposure prophylaxis (PEP) strategy for outbreak control, the effectiveness of this strategy remains unclear. We evaluated the vaccine effectiveness (VE) of 2 nd -dose VarV as PEP among students involved in 129 varicella outbreaks in Shanghai, China from 2013 to 2016. Methods: Students who had received one-dose VarV more than 5 years prior to varicella exposure were eligible to receive 2 nd -dose VarV as PEP. We evaluated the VE using the following formula: VE ¼ (1 e hazard ratio (HR)) Â 100%. Results: A total of 6762 students were eligible for 2 nd -dose VarV, of whom 58.6% accepted PEP after varicella exposure. The adjusted VE of 2 nd -dose VarV as PEP was 77% (95% confidence interval 64e85%). In addition, the adjusted VE of 2 nd -dose VarV as PEP in affected classrooms with high vaccine uptake was higher than that in classrooms with lower vaccine uptake (87% vs. 69%). The adjusted VE was also higher in students who received 2 nd -dose VarV within 3 days of exposure than those who received it more than 3 days post exposure (77% vs. 64%). Conclusions: These Results suggest that administration of 2 nd -dose VarV as PEP is an appropriate intervention for outbreak control in countries where two-dose VarV has not been adopted.
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