In vitro and in vivo CT imaging using bismuth sulfide modified with a highly biocompatible Pluronic F127.

Probe bismuth sulfide modified with Pluronic F127 (Bi2S3-PF127), which has high biocompatibility and dispersibility, is synthesized using triblock copolymer Pluronic F127 to modify hydrophobic Bi2S3 nanoparticles that are prepared by a hot injection method. TEM results show that most of the probe has a length of about 14.85 ± 1.70 nm and a breadth of about 4.79 ± 0.63 nm. After injected into the tail vein of a mouse, the probe has obvious CT contrast enhancement capability from x-ray CT imaging results. Meanwhile, the probe's in vivo toxicity is also studied. It is found that hematoxylin and eosin stains of major organs have no change. A biochemical analysis (alanine aminotransferase and aspartate aminotransferase) prove the probe has no adverse effects. The results of a blood analysis (white blood cell count, red blood cell count, hemoglobin, and platelet count) are also normal. The biological distribution of Bi by ICP-AES shows that most of nanoparticles are cleaned out after injection 48 h, and the circulation half-life of the probe is 5.0 h, suggesting that Bi2S3-PF127 has a long circulation and indicating that the Bi2S3-PF127 probe has good biocompatibility and safety.

Facile Synthesis of Gold Nanospheres Modified by Positively Charged Mesoporous Silica, Loaded with Near-Infrared Fluorescent Dye, for in Vivo X-ray Computed Tomography and Fluorescence Dual Mode Imaging.

We developed a simple and efficient method to synthesize a novel probe for both computed tomography (CT) and fluorescence imaging. Gold nanospheres were coated with positively charged mesoporous silica (Au@mSiO2-TTA) using a one-pot method to cohydrolyze quaternary ammonium silane and tetraethyl orthosilicate. Subsequently, IR-783, a negatively charged and water-soluble near-infrared fluorescent dye, was electrostatically adsorbed into the silica shell. Transmission electron microscopy imaging, X-ray powder diffraction, and energy dispersive X-ray spectroscopy indicated that Au@mSiO2-TTA had a clear core-shell structure, was monodisperse, had a large surface area (530 m2/g), and had a uniform pore size (2.2 nm). The mesoporous structure could effectively load fluorescent dye. After loading, the zeta potential of the nanoparticle dropped from 48 mV to 30 mV, and after additional modification with polyvinylpyrrolidone, it further reduced to 6 mV. Probe fluorescence was stable over time, and the probe was an effective CT contrast agent and as a near-infrared fluorescent probe. The half-life of the probe in the blood was 1.5 h, and the probe was mainly distributed in the spleen and liver 4 h after injection. Tissue sections showed that major organs were normal and without visible morphological changes, 6 days post injection, indicating the biocompatibility of the probe.

Composite silica coated gold nanosphere and quantum dots nanoparticles for X-ray CT and fluorescence bimodal imaging.

In this study, silica coated Au nanospheres (Au@SiO2) were prepared by a reverse microemulsion method; subsequently, a layer of fluorescent quantum dots (QDs) were adsorbed onto it and then it was coated with silica again. After modifying with PVP, the composite silica coated gold nanosphere and quantum dots nanoparticle (Au@SiO2-QDs/SiO2-PVP) was obtained. This composite structure contained Au and QDs, and it could be used for contrast-enhanced X-ray CT imaging and fluorescence imaging. Characterization showed that the composite nanoparticle had good dispersity, a high fluorescence intensity and a good effect of X-ray absorption, and it was suitable for using as a bimodal imaging probe.

Reverse microemulsion-mediated synthesis of Bi2S3-QD@SiO2-PEG for dual modal CT-fluorescence imaging in vitro and in vivo.

Monodispersed Bi2S3-QD@SiO2-PEG nanoparticles are prepared by a one-pot method in a reverse microemulsion system, which exhibited remarkable performances in CT and fluorescence imaging in vitro and in vivo.

[Rash and fever illness caused by herpes simplex virus type 1 needs to be distinguished from hand, foot and mouth disease].

An epidemic of rash and fever illnesses suspected of hand, foot and mouth disease (HFMD) occurred in Gansu Province of China in 2008, laboratory tests were performed in order to identify the pathogen that caused this epidemic. Eight clinical specimens collected from the 4 patients (each patient has throat swab and herpes fluid specimens) with rash and febrile illness, were inoculated onto RD and HEp-2 cells for virus isolation, and the viral nucleic acid was then extracted with the positive virus isolates, the dual-channel real-time reverse transcript-polymerase chain reaction (RT-PCR) was performed to detect the nucleic acid of human enterovirus (HEV) in the viral isolates at the same time. For the viral isolates with the negative results of HEV, a sequence independent single primer amplification technique (SISPA) was used for "unknown pathogen" identification. Totally, 6 viral isolates were identified as herpes simplex virus type 1 (HSV-1). Comprehensive analyses results of the clinical manifestations of the patients, epidemiological findings and laboratory test indicated that this epidemic of rash and febrile illness was caused by HSV-1. The differences among the gG region of 6 HSV-1 isolates at nucleotide level and amino acid level were all small, and the identities were up to 98. 8% and 97.9%, respectively, showing that this outbreak was caused by only one viral transmission chain of HSV-1. HSV-1 and other viruses that cause rash and febrile illnesses need differential diagnosis with HFMD. The etiology of rash and febrile illness is sometimes difficult to distinguish from the clinical symptoms and epidemiological data, the laboratory diagnosis is therefore critical.

[RT-PCR identification and genetic characterizations of VP1 region of human enterovirus 71 isolated in Beijing in 2008].

OBJECTIVE: To study the genetic characterizations of VP1 region of Human enterovirus 71 (HEV71) isolated from clinical specimens of hand, foot and mouth disease (HFMD) patients in Beijing in 2008. METHODS: 285 clinical samples were collected from HFMD patients in hospitals and day-care centers in Chaoyang district. They were performed by reverse transcription-polymerase chain reaction (RT-PCR) specific for HEV71. 10 HEV71 isolates were selected for entire VP1 coding gene amplification and sequencing. RESULTS: 129 samples were RT-PCR positive, the positive rate is 45.26%. The homology of the nucleotide and the amino acid of the 10 strains were 94.6%-99.6% and 95.9%-100%. The phylogenetic tree revealed that 10 Beijing strains clustered within the C4a evolution branch of C4 subgenotype. CONCLUSIONS: RT-PCR played an important role in identifying HFMD outbreak in Beijing in 2008. The HEV71 strains were all belong to C4a evolution branch of C4 subgenotype with several transmission chains, and it showed that C4 subgenotype HEV71 spread in mainland China widely after 1998. The molecular epidemiology surveillance and the research of genetic characterizations of HEV71 should be strengthened in mainland China.

[Genetic characterization of coxsackievirus A16 isolated in Ningxia Hui Municipality in 2008].

OBJECTIVE: To study the genetic characterization of coxsackievirus A16 (CVA16) strains isolated during an epidemic of hand, foot, and mouth disease (HFMD) in Ningxia Hui Municipality in 2008. METHODS: Clinical samples were collected from HFMD patients in Ningxia Hui Municipality and CVA16 strains were isolated by viral isolation methods. Reverse transcription-polymerase chain reactions (RT-PCR), specific for CVA16 were performed with these CVA16 strains. Entire VP1 coding region amplification and sequencing were then performed and finally phylogenetic tree was constructed among Ningxia CVA16 strains and CVA16 representative strains of known genotypes and subgenotypes. RESULTS: 70 Ningxia CVA16 strains were isolated from HFMD patients in Ningxia in 2008 and the homology of nucleotide and amino acid were 90.8%-100.0% and 98.9% - 100.0%, respectively. Phylogenetic characteristics of the strains reconfirmed that they could be divided into two distinct genotypes-A and B. Genotype B could be further divided into the subgenotypes B1 and B2, while all the 70 Ningxia CVA16 strains belonged to the co-circulated clusters B1a and B1b within subgenotype B1, which belonged to 2 viral transmission chains. CONCLUSION: Our results indicated that subgenotype B1 CVA16 strains continued to circulate over a wide geographic area of mainland China since the first reported episode in Shenzhen city in 1999. Like other CVA16 strains isolated elsewhere in China, both B1a and B1b evolution branches were co-circulating in Ningxia Hui Municipality. Based on the close phylgenetic and chronological relationship with CVA16 isolated in other countries and regions near China. Our data confirmed that these strains co-evolved and co-circulated with those from neighboring countries and regions.

[Genetic characterization of enterovirus 71 stains isolated in Ningxia province in 2008].

OBJECTIVE: To study the genetic characterization of enterovirus 71 (EV71) strains isolated from specimens of patients with hand-foot-mouth disease (HFMD) in Ningxia province in 2008. METHODS: All the stool, throat swab and vesicle samples that collected from patients with HFMD were cultured. The positive isolates were identified by reverse transcriptase PCR (RT-PCR) with specific primers of EV71. Complete VP1 gene sequences (891 nucleotides) of 29 strains (part of 93 EV71 strains) were determined and compared with A, B and C genotype reference EV71 strains while EV71 China isolates by homogeneity and phylogenetic tree analyses. RESULTS: 215 strains of EV were isolated from 439 specimens. Results from RT-PCR indicated that 93 strains belong to EV71. Phylogenetic tree analysis revealed that the selected 29 stains were clustered with reference strains of C4 subgenotype. The nucleotide identity with C4 reference strains was 91.7%-99.4%. The amino acid homogeneity was 96.6%-100.0%. CONCLUSION: The recently identified EV71 strains in Ningxia province belonged to subgenotype C4 which resembled to most of the isolates in China.

[The epidemiologic and virological analysis of an outbreak of hand, foot, and mouth disease in Inner Mongolia in 2007].

In 2007, an outbreak of hand, foot, and mouth disease (HFMD) occurred in Jungar Banner, Erdos city, Inner Mongolia Autonomous Region, China Fever, vesicular exanthema on the hands, feet, mouth, and buttocks were presented in most of the patients. Most of the patients were infants less than 5 years old, and an obvious peak period appeared in the disease outbreak. From 28 hospitalized patients, 23 stool specimens and 6 throat swab specimens were collected for enterovirus isolation, and 15 enteroviruses were isolated, 9 were identified as Human Enterovirus 71 (HEV71, the isolation rate is 31.03%) and 1 was identified as Coxsackievirus A16 (CVA16). According to the comprehensive analysis of clinical manifestation, epidemiology data and laboratory results, this outbreak was probably mainly caused by HEV71. The variability at nucleotide acid level and amino acid level among 9 HEV71 was relatively low, and the homology was more than 99.4% and 99.0% respectively, showing that this outbreak was caused by only one viral transmission chain. Phylogenetic analysis of 9 HEV71 strains isolated during this outbreak revealed that they all belonged to subgenotype C4, which has been continuously circulating in mainland China since its first reported occurrence in Shenzhen City in 1998. It was also suggested that subgenotype C4 HEV71 had a widely distribution and transmission in mainland China.

An outbreak of hand, foot, and mouth disease associated with subgenotype C4 of human enterovirus 71 in Shandong, China.

BACKGROUND: An outbreak of hand, foot, and mouth disease (HFMD) included 1149 people in Linyi City, Shandong Province, China, in 2007: three children died. OBJECTIVES: To characterize the pathogens responsible for this outbreak and to analyze their genetic features. STUDY DESIGN: A total of 233 clinical specimens were collected from 105 hospitalized patients, including 11 patients with severe HFMD. Virological investigations (direct RT-PCR, viral isolation and molecular identification) and phylogenetic analysis were performed. RESULTS: Human enterovirus 71 (HEV71) was the main pathogen that caused this outbreak, based on clinical manifestations, epidemiological data, and laboratory results. Phylogenetic analysis indicated that the Shandong HEV71 isolates belonged to 3 lineages in subgenotype C4. Subgenotype C4 could be further divided into two clusters (C4a and C4b), which corresponded to two time periods. Cluster C4a HEV71 has been the predominant virus circulating in mainland China in the past 5 years. CONCLUSIONS: The 2007 HFMD outbreak was mainly caused by HEV71 subgenotype C4 with 3 transmission chains. This virus has been continuously circulating in China since 1998. The Shandong strains co-evolved with isolates from other provinces in mainland China and neighboring countries.