Plasmon Coupling Enhanced Micro-Spectroscopy and Imaging for Sensitive Discrimination of Membrane Domains of a Single Cell.

Different cell membrane domains play different roles in many cell processes, and the discrimination of these domains is of considerable importance for the elucidation of cellular functions. However, the strategies available for distinguishing these cell membrane domains are limited. A novel technique called plasmon coupling enhanced micro-spectroscopy and imaging to discriminate basal and lateral membrane domains of a single cell combines the application of an additional plasmonic silver film for surface plasmon (SP) excitation to selectively excite and enhance the basal membranes in the near-field with directional enhanced microscopic imaging and spectroscopy. The SP and critical evanescent fields are induced upon excitation through a silver-coated semitransparent coverslip at the surface plasmon resonance and critical angles, respectively. The basal and lateral membrane domains located within the SP and critical evanescent fields can be selectively excited and distinguished by adjusting the incident angle of laser irradiation. Moreover, the brighter images and more intense spectra of membrane-targeting fluorescence-Raman probes under directional excitation than in conventional EPI mode allow clear identification of the membrane domains.

Study on the COVID-19 infection status, prevention and control strategies among people entering Shenzhen.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) confirmed cases overseas have continued to rise in the last months, and many people overseas have chosen to return to China. This increases the risk of a large number of imported cases which may cause a relapse of the COVID-19 outbreak. In order to prevent imported infection, the Shenzhen government has implemented a closed-loop management strategy using nucleic acid testing (NAT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and requiring 14 days of medical observation for individuals with an overseas tour history (Hong Kong, Macao, Taiwan province and other countries). Our study aims to describe the status of COVID-19 infection among people entering Shenzhen, and to evaluate the effect of the closed-loop management strategy. METHODS: We undertook a descriptive study and risk analysis by the entry time, time of reporting, and local confirmed cases in countries of origin. The NAT were completed in Shenzhen Center for Disease Control and Prevention (CDC), ten district-level CDCs, and fever clinics. RESULTS: A total of 86,844 people from overseas entered Shenzhen from January 1 to April 18, 2020; there were 39 imported COVID cases and 293 close contacts. The infection rate of people entering was 4.49‰ [95% Confidence interval (CI): 3.26‰-6.05‰]. Fourteen imported cases (35.9%) came from the UK, and nine (23.08%) came from the USA. People entering from the USA since March 9 or from the UK since March 13 are the high-risk population. As of July 17, there have been no new confirmed cases in Shenzhen for 153 days, and the numbers of confirmed case, close contacts, and asymptomatic cases are 0. CONCLUSIONS: The closed-loop management has been effective in preventing imported infection and controlling domestic relapse. The distribution of entry time and report time for imported cases overseas was similar. This shows that it is important to implement closed-loop management at the port of entry.

In situ and sensitive monitoring of configuration-switching involved dynamic adsorption by surface plasmon-coupled directional enhanced Raman scattering.

Surface adsorption studies play a crucial role in numerous fields from surface catalysis to molecular separation. However, investigation on adsorption mechanisms has been restricted to limited analytes and approaches, which calls for an in situ and sensitive surface analysis technique capable of revealing the mechanisms as well as discriminating different adsorbates and their geometry at different adsorption stages. In this study, we employed surface plasmon-coupled directional enhanced Raman scattering (SPCR), a novel technique developed by coupling surface plasmon-coupled emission with SERS, to study conformation-switching involved dynamic adsorption with background suppression and improved sensitivity (nearly 30-fold). We obtained the isotherms for a conformation-changing Raman model analyte, malachite green. An S-type Langmuir model was fitted from the time-resolved SPCR signals sensitively and without any interference from the bulk solution. The reorientation of the analyte from a predominantly parallel configuration to a perpendicular one was captured by the dramatic increase in the intensity ratios of the adsorption-related peaks to the adsorption-unrelated peak. We believe that this new sensitive and selective SPCR technique will be a promising tool for surface adsorption kinetics analysis.

Gene Knockdown in Human Rhinovirus 1B Using 2'-OMe-modified siRNAs Results in the Reactivation of the Interferon Response.

The aim of this study was to investigate the knockdown efficiency of 2'-O-methylated (2'-OMe)-modified small interfering RNAs (siRNAs) on human rhinovirus 1B (HRV1B) replication and the interferon response. Thus, 24 2'-OMe-modified siRNAs were designed to target HRV1B. The RNA levels of HRV1B, Toll-like receptor 3, melanoma differentiation-associated gene 5, retinoic acid inducible gene-I, and interferons were determined in HRV1B-infected HeLa and BEAS-2B epithelial cells transfected with 2'-OMe-modified siRNAs. The results revealed that all 2'-OMe-modified siRNAs interfered with the replication of HRV1B in a cell-specific and transfection efficiency-dependent manner. Viral activation of Toll-like receptor 3, melanoma differentiation-associated gene 5, retinoic acid inducible gene-I, and the interferon response was detected. In conclusion, the 2'-OMe-modified siRNAs used in this study could interfere with HRV1B replication, possibly leading to the reactivation of the interferon response.

Norovirus Infection and Histo-blood Group Antigens in Children Hospitalized with Diarrhea in Lulong and Chenzhou in China.

Norovirus (NoV) is a pathogen that commonly causes viral diarrhea in children. Studies indicate that NoV recognizes human histo-blood group antigens (HBGAs) as cell attachment factors. In order to explore the correlation between of NoV infection and HBGAs, a cross-sectional study was conducted in children less than five years old who were hospitalized with diarrhea in two areas of China between November 2014 and February 2015. Of the paired stool and saliva samples taken from 424 children, NoV was detected in 24 (6%) children, with viral genotypes GII.3 (n=5), GII.4 (n=14), GII.12 (n=1), and GII.17 (n=4). All of the individuals having NoV infection were either secretors (Lea-b+/Lex-y+) or partial secretors (Lea+b+/Lex+y+) except one GII.3 infection of a non-secretor (Lea+b-/Lex+y-). These results suggest that secretor positive is associated with NoV infection, although non-secretors are not absolutely protected from NoV infection.

Hepatic interleukin 32 attenuates liver injury through repression of necroptosis in cholestasis.

OBJECTIVE: We aimed to evaluate the association between interleukin (IL)-32 and necroptosis in cholestatic liver injury. METHODS: Levels of necroptosis-related markers in cholestatic and control patients, including the receptor-interacting serine-threonine kinase 3 (RIPK3), receptor-interacting serine-threonine kinase 1 (RIPK1), and mixed lineage kinase domain-like (MLKL) were measured. Animal experiments in C57BL/6J and transgenic mice with IL32ß/γ overexpression were also conducted to confirm the effect of IL-32 on necroptosis in cholestasis, which was induced by α-naphthylisothiocyanate (ANIT) and 1% lithocholic acid (LCA). PLC/PRF/5-ASBT and primary mouse hepatocytes were utilized for the investigation of the regulation and mechanism of IL-32 in cholestasis. RESULTS: In the liver tissues of cholestatic patients, the mRNA and protein expressions of RIPK1, RIPK3, and MLKL were increased and associated with IL-32 expression. In addition, expressions of these indicators in the liver of 1% LCA- and ANIT-induced mouse models were significantly increased, while they were markedly decreased in hIL32ßLTg and hIL32γLTg mice. After bile acid stimulation, IL-32 and phosphorylated Akt (p-Akt) expressions significantly elevated in a dose-dependent manner. After treated with tumor necrosis factor (TNF)-α, IL-32 inhibited MLKL expression in primary mouse hepatocytes. CONCLUSION: IL-32 is negatively associated with necroptosis in cholestatic patients. Moreover, IL-32 is induced by p-Akt and effectively attenuates necroptosis in ANIT- or 1% LCA-induced cholestasis.

Simultaneous detection of seven enteric viruses associated with acute gastroenteritis by a multiplexed Luminex-based assay.

Rapid and broad diagnostic methods are needed for the identification of viral agents of gastroenteritis. In this study, we used Luminex xMAP technology to develop a multiplexed assay for the simultaneous identification of major enteric viral pathogens, including rotavirus A (RVA), noroviruses (NoVs) (including genogroups GI and GII), sapoviruses (SaV), human astrovirus (HAstV), enteric adenoviruses (EAds), and human bocavirus 2 (HBoV2). The analytical sensitivity allowed detection of 10(3) (EAds, HBoV2, and RVA) and 10(4) (NoV GI and GII, SaV, and HAstV) copies per reaction mixture. Compared to conventional PCR, the Luminex-based assay yielded greater than 75% sensitivity and 97% specificity for each virus, and the kappa correlation for detection of all viruses ranged from 0.75 to 1.00. In conclusion, this multiplexed Luminex-based assay provides a potentially rapid, high-throughput, and maneuverable diagnostic tool for major viral pathogens associated with gastroenteritis.

Development of a real-time PCR assay for detecting and quantifying human bocavirus 2.

Human bocavirus 2 (HBoV2) is a parvovirus that has been recently identified in stool samples from children. Any association between the virus and clinical disease is unclear. A rapid, reliable diagnostic method is necessary to address this issue. In this study, we developed a sensitive and specific HBoV2 quantitative real-time PCR assay that targets the HBoV2 NP-1 gene, based on the TaqMan method. The assay could reproducibly detect 10 copies of a recombinant DNA plasmid containing a partial region of the HBoV2 genome, with a dynamic range of 8 log units (10(1) to 10(8) copies). A clinical evaluation detected HBoV2 in 85 (24.6%) of 345 children with gastroenteritis, with viral loads ranging from 1.67 × 10(2) to 4.27 × 10(9) copies per ml of stool specimen.

Analysis and characterization of the complete genome of a member of a new species of kobuvirus associated with swine.

A virus belonging to a new species in the genus Kobuvirus, family Picornaviridae, was first isolated in 2008 from apparently healthy pigs in Hungary and China. We report the complete genome sequence and the genetic organization of the novel porcine kobuvirus strain Y-1-CHI, which was identified in China. The RNA genome of strain Y-1-CHI contains 8210 nucleotides (nt) and has an organization similar to that of other picornaviruses. The full-length nucleotide sequence of Y-1-CHI was 88.62%, 58.66%, and 48.86% identical to those of S-1-HUN, U-1, and Aichi virus, respectively. No positive results were found in 454 stool samples from children with acute gastroenteritis. Dendrograms indicated that Y-1-CHI and S-1-HUN are most closely related to each other and belong to the same species. Our results suggest that members of this novel species have the typical genome characteristics of members of the genus Kobuvirus and may be distributed globally in swine.

Novel human bocavirus in children with acute respiratory tract infection.

Human bocavirus (HBoV) and HBoV2, two human bocavirus species, were found in 18 and 10 of 235 nasopharyngeal aspirates, respectively, from children hospitalized with acute respiratory tract infection. Our results suggest that, like HBoV, HBoV2 is distributed worldwide and may be associated with respiratory and enteric diseases.

Human bocavirus infection in young children with acute respiratory tract infection in Lanzhou, China.

Human bocavirus (HBoV) is a recognized human parvovirus associated with acute respiratory tract infection. However, HBoV has yet to be established as a causative agent of respiratory disease. In this study, the epidemiological and virological characteristics of HBoV infection were studied in children with acute respiratory tract infection in China. In total, 406 children younger than 14 years of age with acute respiratory tract infection were included in this prospective 1-year study. HBoV was detected in 29 (7.1%) of the 406 children. No clear seasonal fluctuation was observed in infection rates of HBoV. Of the 29 children infected with HBoV, 16 (55.2%) were coinfected with other respiratory viruses, most commonly respiratory syncytial virus (RSV). Viral coinfection with HBoV did not affect the severity of the respiratory disease (P = 0.291). The number of HBoV genome copies ranged from 5.80 x 10(2) to 9.72 x 10(8) copies/ml in nasopharyngeal aspirates among HBoV-positive specimens by real-time PCR, and neither coinfection nor the severity of disease correlated with the viral load (P = 0.148, P = 0.354, respectively). The most common clinical features were cough and acute upper respiratory infection, and acute bronchopneumonia. Additionally, the NP-1 gene of HBoV showed minimal sequence variation. These data suggest that HBoV is frequent in young children with acute respiratory tract infection in Lanzhou, China, and RSV is the most common coinfecting virus. There was no apparent association between the viral load of HBoV and coinfection or disease severity. The NP-1 gene was highly conserved in HBoV.

Positron emission computed tomography/single photon emission computed tomography in Parkinson disease.

Parkinson disease (PD) is the second-most common neurodegenerative disorder. Its main pathological mechanism is the selective degeneration and deletion of dopaminergic neurons in the dense part of the substantia nigra and the damage of dopaminergic neurons caused by the abnormal deposition of a Lewy body, leading to a decreased dopamine level. Positron emission computed tomography (PET)/single photon emission computed tomography (SPECT) is a molecular imaging technology that can directly or indirectly reflect changes in molecular levels by using a specific tracer. With the research and development on the tracers of related enzymes for labeling dopamine transporter and dopamine receptor and for being involved in dopamine formation, this imaging technology has been applied to all aspects of PD research. It not only contributes to clinical work but also provides an important theoretical basis for exploring the pathological mechanism of PD at a molecular level. Therefore, this review discusses the application value of PET/SPECT in PD in terms of early diagnosis, disease severity evaluation, clinical manifestations, differential diagnosis, and pathological mechanism.

Prevalence and clinical characterization of a newly identified human rhinovirus C species in children with acute respiratory tract infections.

Human rhinovirus C (HRV-C) is a newly identified genotype of HRV found in patients with respiratory tract infections (RTIs); however, its epidemiological profile and clinical characteristics are not well understood. In this study, Chinese children with RTIs were screened for HRV-C and their epidemiological and clinical characteristics were analyzed. From December 2006 to November 2007, 406 nasopharyngeal aspirates from children younger than 14 years of age with RTIs were screened for HRV and other common respiratory viruses by PCR or reverse transcription-PCR. Two-hundred twenty-four (55.2%) of the specimens were infected with at least one virus, including 53 patients with HRV (13%). HRV-A, HRV-B, and HRV-C were detected in 22, 12, and 19 specimens, respectively. HRV-C was detected mainly from December 2006 to April 2007 and from October to November 2007, with peaks in December and April (10/19). Acute upper respiratory infection and bronchopneumonia were observed in 53 and 37% of the cases, respectively. The most common symptoms were cough (82%), runny nose (53%), and fever (37%). Wheezing and bronchiolitis were less common in patients infected with HRV-C than in those infected with respiratory syncytial virus (RSV). Partial sequencing of the genes coding for VP4 and VP2 revealed that the HRV-C strains were 56 to 62% identical at the amino acid level to HRV-B and HRV-A reference strains and 80 to 99% identical to HRV-C reference strains. In conclusion, HRV-C is an important cause of RTIs in children, and highly diversified strains of HRV-C are prevalent in China. HRV-C may produce different epidemiological features, and patients infected with HRV-C may exhibit different clinical features from patients infected with RSV or HRV-A/B.

Human bocavirus in children hospitalized for acute gastroenteritis: a case-control study.

BACKGROUND: Human bocavirus (HBoV) was recently discovered in children with respiratory tract disease and gastroenteritis. The causative role of HBoV in human gastroenteritis remains uncertain, and, to our knowledge, no previous case-control study has studied the relationship between HBoV and gastroenteritis. METHODS: We conducted a case-control study that examined stool samples from 397 children with diarrhea and from 115 asymptomatic control subjects. HBoV was detected using polymerase chain reaction. Real-time polymerase chain reaction was used to quantify the HBoV loads in case and control groups. Common enteric viruses were examined using enzyme-linked immunosorbent assays, polymerase chain reaction, and reverse-transcription polymerase chain reaction. RESULTS: At least 1 viral agent was discovered in 60.2% of cases. HBoV was detected in 14 samples, and 9 were coinfected with either rotavirus (7 of 14 samples) or human calicivirus (2 of 14). Many (8 [57.1%] of 14) of the HBoV infections occurred during September-December 2006. Most (12 [85.7%]) of the HBoV-infected children were 7-18 months of age. The percentage of children with HBoV infection did not differ significantly between case patients and control subjects (3.5% vs. 3.5%), and the statistical analysis did not support a correlation between HBoV infection and more-severe clinical symptoms. The viral load differences between the 2 groups were not statistically significant (P = .09, by log-normal Student's t test). In addition, the VP1/VP2 partial gene of HBoV from case patients and control subjects showed minimal sequence variation. CONCLUSIONS: A single genetic lineage of HBoV was revealed in persons in China. Despite its high prevalence in stool samples, our study does not support a causative role of HBoV in gastroenteritis.

Prevalence of human KI and WU polyomaviruses in children with acute respiratory tract infection in China.

The KI and WU polyomaviruses were found in 11 (2.7%) and 17 (4.2%) of 406 nasopharyngeal aspirates, respectively, from children with acute respiratory tract infection (ARTI). The phylogenetic analysis indicates that they are all in the same cluster as the prototype strains. Our findings suggest that they are common in children with ARTI in China.

Emergence of the GII4/2006b variant and recombinant noroviruses in China.

Noroviruses are an important cause of acute gastroenteritis. Increasing data showed that the GII-4 strains are predominant worldwide and new GII-4 variants emerge every 1-2 years causing major epidemics. Surveillance of gastroenteritis in hospitalized children under 5 years of age in China is described. Among 1,110 specimens, 114 (10.3%) were positive for noroviruses, which was higher than adenoviruses (7.6%), astroviruses (3.5%), and sapoviruses (0.9%) and only lower than group A rotaviruses (40.6%). Thirty-eight of the 114 positive norovirus cases were co-infected with other enteric viruses. Five norovirus genotypes (GI-2, GI-4, GII-3, GII-4, and GII-14) were detected, with GII-4/2006b the most predominant type (64.9%). The reported recombinant of GII-3 capsid and GII-4 polymerase described previously was also detected frequently and a recombinant of GII-14 capsid and GII-6 polymerase was found for the first time. This study suggests that continual surveillance focusing on strain variation and dynamic change is important for understanding the epidemiology and development of a strategy for disease control and prevention.

Human bocavirus infection in children hospitalized with acute gastroenteritis in China.

BACKGROUND: Human bocavirus (HBoV) was first identified in children with acute respiratory-tract infections, but recent studies have revealed that HBoV is also frequently detected in fecal specimens from children with gastroenteritis. OBJECTIVES: To investigate the prevalence of HBoV in children hospitalized with gastroenteritis in different areas of China. STUDY DESIGN: Employing ELISA, RT-PCR or PCR, we evaluated 1216 fecal samples for common diarrheal agents from children aged less than 5-year-old hospitalized with acute gastroenteritis. MEGA software was used to construct phylogenetic trees of the VP1/VP2 partial sequences of the HBoV genome. RESULTS: There were 67 HBoV-positive specimens, 52 (77.6%) were co-infected with rotavirus, norovirus, astrovirus, or enteric adenovirus. Statistical analysis of the clinical data indicated that children infected with both rotavirus and bocavirus did not have more severe clinical symptoms than children infected with rotavirus. The phylogenetic analysis of the VP1/VP2 partial sequences of the HBoV genome revealed a single genetic lineage. CONCLUSIONS: Despite its high infection rate, there was no statistically significant a causual relationship between HBoV and gastroenteritis in children.

Dynamic Diffusion Tensor Imaging Reveals Structural Changes in the Bilateral Pyramidal Tracts after Brain Stem Hemorrhage in Rats.

BACKGROUND AND PURPOSE: Few studies have concentrated on pyramidal tract (PY) changes after brain stem hemorrhage (BSH). In this study, we used a diffusion tensor imaging (DTI) technique and histologic identification to investigate longitudinal PY changes on both the contralateral and ipsilateral sides after experimental BSH. METHODS: BSH was induced in 61 Sprague-Dawley rats by infusing 30 µl of autogenous tail blood into each rat's right pons. DTI and motor function examinations were performed repeatedly on days 1, 3, 7, 14, and 28 after surgery. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity were measured in the bilateral PYs. The axon and myelin injury in the PY were evaluated by histologic study. RESULTS: As compared with normal controls, the bilateral PYs in rats with induced BSH showed an early decrease and a late increase in FA and an early increase and a late decrease in MD. A progressive decrease in axial diffusivity with dramatic axon loss from day 1 to day 28 after BSH was found bilaterally. The bilateral PYs showed an early increase and a late decrease in radial diffusivity. Early myelin injury and late repair were also detected pathologically in the bilateral PYs of rats with BSH. Thus, the early motor function deficits of rats with BSH began to improve on day 14 and had almost completely disappeared by day 28. CONCLUSIONS: DTI revealed dynamic changes in the bilateral PYs after BSH, which was confirmed by histologic findings and which correlated with motor function alteration. These findings support the idea that quantitative DTI can track structural changes in the bilateral PYs and that DTI may serve as a noninvasive tool to predict the prognoses of patients with BSH.