We describe a novel spike pseudoparticle neutralisation assay (ppNT) for seroepidemiological studies on Middle East respiratory syndrome coronavirus (MERS-CoV) and apply this assay together with conventional microneutralisation (MN) tests to investigate 1,343 human and 625 animal sera. The sera were collected in Egypt as a region adjacent to areas where MERS has been described, and in Hong Kong, China as a control region. Sera from dromedary camels had a high prevalence of antibody reactive to MERS-CoV by MERS NT (93.6%) and MERS ppNT (98.2%) assay. The antibody titres ranged up to 1,280 and higher in MN assays and 10,240 and higher in ppNT assays. No other investigated species had any antibody reactivity to MERS-CoV. While seropositivity does not exclude the possibility of infection with a closely related virus, our data highlight the need to attempt detection of MERS-CoV or related coronaviruses in dromedary camels. The data show excellent correlation between the conventional MN assay and the novel ppNT assay. The newly developed ppNT assay does not require Biosafety Level 3 containment and is thus a relatively high-throughput assay, well suited for large-scale seroepidemiology studies which are needed to better understand the ecology and epidemiology of MERS-CoV.

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Severe acute respiratory syndrome coronavirus (SARS-CoV) is a recently identified human coronavirus. The extremely high homology of the viral genomic sequences between the viruses isolated from human (huSARS-CoV) and those of palm civet origin (pcSARS-CoV) suggested possible palm civet-to-human transmission. Genetic analysis revealed that the spike (S) protein of pcSARS-CoV and huSARS-CoV was subjected to the strongest positive selection pressure during transmission, and there were six amino acid residues within the receptor-binding domain of the S protein being potentially important for SARS progression and tropism. Using the single-round infection assay, we found that a two-amino acid substitution (N479K/T487S) of a huSARS-CoV for those of pcSARS-CoV almost abolished its infection of human cells expressing the SARS-CoV receptor ACE2 but no effect upon the infection of mouse ACE2 cells. Although single substitution of these two residues had no effects on the infectivity of huSARS-CoV, these recombinant S proteins bound to human ACE2 with different levels of reduced affinity, and the two-amino acid-substituted S protein showed extremely low affinity. On the contrary, substitution of these two amino acid residues of pcSARS-CoV for those of huSRAS-CoV made pcSARS-CoV capable of infecting human ACE2-expressing cells. These results suggest that amino acid residues at position 479 and 487 of the S protein are important determinants for SARS-CoV tropism and animal-to-human transmission.

Objective: The outbreak of the coronavirus disease (COVID-19) poses an unprecedented threat to public health. Current measures to control the spread include social distancing and quarantine, which may trigger mental health problems. Design and Main Outcome Measures: The sample (N ¼ 1160) constituted three groups: people quarantined in an affected area, unaffected areas, and people not in quarantine. The Center for Epidemiological Studies Depression Scale (CES-D-20) and the Goldberg Depression and Anxiety Scale (GAD-7) were administered as measures of depression and anxiety, respectively. The multi-variant logistic and multiple linear regression identified factors associated with depression and anxiety. Results: Probable depression and anxiety were reported by 26.47% and 70.78% of all respondents, respectively. After adjusting for demographic and community variables, quarantined respondents reported a higher likelihood to exhibit symptoms of depression and anxiety than those not quarantined. Respondents living in communities where screening for COVID-19 was required were less likely to report depression and anxiety symptoms. Conclusion: The incidence of depression and anxiety among quarantined respondents was significantly higher than that of respondents not quarantined, and twice as common among quarantined respondents in unaffected areas as those in affected areas. Appropriate community screening may reduce the risk of depression and anxiety during an epidemic.

Experimental induction of embryonic stem cells (ESCs) to become pancreatic β cells can potentially provide ample resource for cell transplantation therapy of type I diabetes mellitus. Most of the previously reported induction strategies were long and complicated, and some required genetic manipulation. Moreover, it has been indicated that the insulin staining of ESC progeny was insulin uptake from the culture medium. Here we show that a simple three-step experimental approach based on the combination induction by activin A, alltrans retinoic acid, and other mature factors is able to induce murine ESCs to differentiate into insulin-producing cells in 2 weeks, and that insulin release of these induced cells is regulated by the glucose concentration. Our insulin-enhanced green fluorescent green protein reporter system excludes the possibility of insulin uptake. Transplantation of these ESCderived insulin-positive cells can normalize blood glucose levels and rescue the survival of streptozocin-induced diabetic mice. The findings reported here offer a novel in vitro model to study the differentiation mechanism of pancreatic β cells and a potential source of insulin-producing cells for transplantation therapy of type I diabetes mellitus. Stem Cells 2005;23:656-662

BackgroundCancer has become a global health problem. China still suffers continuous increasing cancer mortality. To study the trend of cancer mortality in rural China, this paper established an Age-Period-Cohort model to discuss the age effect, period effect and cohort effect on cancer mortality in rural China.MethodsThe data were collected from the “China Health Statistical Yearbook” from 1990 to 2010. Collected data were analyzed by Age-Period-Cohort model and Intrinsic Estimation method.ResultsThe age effect on the total cancer mortality represented a V trend. Compared with Group 0–4, Group 5–9 showed 71.87% lower cancer mortality risk. Compared with Group 5–9, Group 75–79 showed 38 times higher cancer mortality risk. The period effect on the total cancer mortality risk weakened firstly but then increased. It increased by 35.70% from 1990 to 2010, showing an annual average growth of 1.79%. The cohort effect on the total cancer mortality risk weakened by totally 84.94% from 1906–1910 to 2005–2010. Three “deterioration periods” and three “improvement periods” were witnessed during this period. The malignant cancer mortality varied similarly with the total cancer mortality, while benign cancer mortality and other cancer mortality represented different variation laws.ConclusionsAlthough the total cancer mortality risk is increasing at an accelerated rate, cancer mortality risk in recent born year is decreasing, indicating very important impact of social change on the cancer mortality in rural China.

We have expressed a series of truncated spike (S) glycoproteins of SARS-CoV and found that the N-terminus 14-502 residuals were sufficient to bind to SARS-CoV susceptible Vero E6 cells. With this soluble S protein fragment as an affinity ligand, we screened HeLa cells transduced with retroviral cDNA library from Vero E6 cells and obtained a HeLa cell clone which could bind with the S protein. This cell clone was susceptible to HIV/SARS pseudovirus infection and the presence of a functional receptor for S protein in this cell clone was confirmed by the cell-cell fusion assay. Further studies showed the susceptibility of this cell was due to the expression of endogenous angiotensin-converting enzyme 2 (ACE2) which was activated by inserted LTR from retroviral vector used for expression cloning. When human ACE2 cDNA was transduced into NIH3T3 cells, the ACE2 expressing NIH3T3 cells could be infected with HIV/SARS pseudovirus. These data clearly demonstrated that ACE2 was the functional receptor for SARS-CoV.

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