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Biomedical subjects

X Jiang

Publications and source records attributed to X Jiang.

At least 217 records · Page 12Linked to original sources
PubMed1999

Characterization of a novel human calicivirus that may be a naturally occurring recombinant.

We identified a Norwalk-like calicivirus (CV) whose genome likely was derived from naturally occurring recombination. This strain (Arg320) was detected by the EIA developed against recombinant Mexico virus (rMxV) capsids, but the viral RNA polymerase sequence was closer to Lordsdale virus, in a separate genetic cluster of Norwalk-like viruses. A 3.3 kb cDNA from the RNA polymerase region to the 3' end of the genome of Arg320 was cloned and sequenced. The sequence demonstrated that the capsid region of Arg320 shared 95% amino acid identity with MxV, but 68% identity with Lordsdale virus, while the RNA polymerase region shared 95% identity with Lordsdale virus, but 87% identity with MxV. Pair-wise sequence comparisons identified a potential recombination site at the polymerase/capsid junction. This is the first example of a naturally occurring recombinant in the CV family. Further studies to search for and characterize other strains may be necessary for understanding the genetic diversity of the family.

Caliciviridae↗
PubMed1999

Expression and characterization of Sapporo-like human calicivirus capsid proteins in baculovirus.

Sapporo-like caliciviruses reveal typical calicivirus morphology and cause acute gastroenteritis. This study describes the expression in baculovirus of capsid proteins of two Sapporo-like calicivirus strains (Hou/86 and Hou/90). Eight different constructs of the capsid genes were compared for production of the proteins. Constructs containing short (9 or 19 nt) upstream sequences failed to produce capsid proteins but extension of the upstream sequence to 73 nt resulted in production of capsid proteins. Expressed capsid protein with the MEG tri-peptide as the N-terminus self-formed virus-like particles (VLPs). Expressed protein with an upstream AUG failed to form VLPs. Addition of His-tag to the N-terminus of capsid protein also blocked VLP formation. Of three Norwalk-Hou/90 chimeric capsid gene constructs, one resulted in production of chimeric capsid and the protein did not form VLPs. Recombinant capsid proteins for each of Hou/86 and Hou/90 were further characterized. The expressed capsid antigens of the two strains were antigenically distinct but shared a common epitope(s). Further study of these proteins should allow development of immunologic assays for diagnosis and should help to clarify the epidemiology of Sapporo-like caliciviruses in humans.

Adult↗
PubMed1999

Design and evaluation of a primer pair that detects both Norwalk- and Sapporo-like caliciviruses by RT-PCR.

A primer pair (p289/290) based on the RNA polymerase sequence of 25 prototype and currently circulating strains of human caliciviruses (HuCVs) was designed for the detection of both Norwalk-like caliciviruses (NLVs) and Sapporo-like caliciviruses (SLVs) by reverse transcription-polymerase chain reaction (RT-PCR). This primer pair produces RT-PCR products of 319 bp for NLVs and 331 bp for SLVs. The usefulness of this primer pair was shown by its detection of prototype NLVs (Norwalk, Snow Mountain, Hawaii and Mexico viruses) and SLVs (Sapporo/82, Hou/86, Hou/90 and Lon/92) and currently circulating strains of NLVs and SLVs in children and adults. This primer pair also detected more viruses in either NLV or SLV genera than previously designed primers. This primer pair is useful for broad detection of HuCVs for clinical and epidemiologic studies as well as for environmental monitoring.

Adult↗
PubMed1999

An NMR study of the structural basis of the wide range of pharmacological functions of acetylsalicylic acid.

The interaction between acetylsalicylic acid (aspirin) and membrane was studied by NMR spectra. (1) NMR spectra showed acetylsalicylic acid did not insert into membrane; (2) 1H NMR spectrum recorded by spin-echo pulse sequence showed protons of the aromatic ring interacted with membrane; (3) the change of spin-lattice relaxation (T1) of 31P was ascribed to the association of acetylsalicylic acid to the polar head of lecithin; (4) the self-diffusion coefficient measured by pulsed field gradients NMR showed the mobility of acetylsalicylic acid was restricted by membrane and that acetylsalicylic acid changed membrane viscosity. Based on the results, the relationship between the interaction and the mechanism of the wide pharmacological functions of acetylsalicylic acid is discussed.

Aspirin↗
PubMed1999

Molecular epidemiology of childhood astrovirus infection in child care centers.

This study assessed the role of human astrovirus (HAstV) in outbreaks and sporadic cases of diarrhea among children attending child care centers (CCCs) and determined the infecting astrovirus antigenic types by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequence analysis. Eight astrovirus outbreaks occurred in 6 CCCs. Of 179 children with diarrhea, 36 (20%) had astrovirus-associated diarrhea. Diarrhea stools obtained during diarrhea outbreaks were more likely to contain astrovirus (40/476) than were samples not associated with a diarrhea outbreak (14/452) (P<.001). Type-specific RT-PCR and DNA sequencing identified 5 outbreaks associated with HAstV-1 and 3 outbreaks with HAstV-2. Sequential outbreaks in 2 CCCs occurred with a different type in the same year. Phylogenetic analysis identified 6 clades of HAstV-1 and 2 clades of HAstV-2 during this 1-year surveillance. Astrovirus was a significant cause of diarrhea outbreaks, and 2 antigenic types were present in the community during 1 diarrhea season.

Animals↗
PubMed1999

Discounted expressions of traits in broiler breeding programs.

The commercially grown broiler usually is a crossbred from specialized purebred sire and dam lines. The position of a purebred line in the crossbreeding system influences its genetic contribution to expression of productive and reproductive performance at different stages of the production column and, thus, influences the breeding goal for a given line. In broiler breeding, cumulative discounted expressions (CDE) should be considered to define breeding goals for multi-trait selection. In the present study, a systematic design for the application of discounted gene flow methodology to derive CDE for production and reproduction traits in broiler breeding was developed. Factors considered as influencing the magnitude of CDE were: crossbreeding system (two-way, three-way, and four-way cross), selection scheme (with and without progeny testing and intensity of selection), selection path, trait (production at commercial stage and reproduction at either nucleus or multiplier stage), interest rate, and time horizon for evaluation. Performance data from a commercial breeding stock were applied in the analysis. Results indicated that levels of CDE were significantly affected by all factors studied. The more that pure lines were included in the crossbreeding system, the lower the CDE for a particular selection path. However, the summation of all selection paths did not differ much among crossbreeding systems. Progeny testing decreased CDE by increasing generation intervals. The CDE for reproduction traits were higher than those for production traits mainly as a result of earlier expression of the reproduction traits.

Animal Husbandry↗
PubMed1999

Expression and self-assembly of Grimsby virus: antigenic distinction from Norwalk and Mexico viruses.

A cDNA obtained from Grimsby virus (GRV), a Norwalk-like virus, purified from a stool sample of a symptomatic adult associated with a gastroenteritis outbreak in the United Kingdom, was used to obtain the complete nucleotide sequence of the second open reading frame (ORF2). The ORF2 sequence of GRV predicts a capsid of 539 amino acids (aa) which exhibits aa identities of 96% to Lordsdale virus, 67% to Mexico virus (MXV), and 43% to Norwalk virus (NV). The GRV capsid protein was expressed in insects cells by using a recombinant baculovirus, and the resulting virus-like particles (VLPs) possessed a protein with an apparent molecular weight of 58,000. Hyperimmune antisera raised against purified GRV, MXV, and NV VLPs were tested in an indirect enzyme-linked immunosorbent assay (ELISA) against GRV, NV, and MXV VLPs, revealing that GRV is antigenically distinct from both NV and MXV. The antigenic specificity of the GRV-hyperimmune antiserum was confirmed in an antigen capture ELISA using GRV-, NV-, or MXV-containing fecal specimens. The expression of the GRV capsid protein has, for the first time, allowed the antigenic comparison of three distinct recombinant Norwalk-like viruses.

Adult↗
PubMed1999

Immunoglobulin M antibody test to detect genogroup II Norwalk-like virus infection.

Sera obtained from adult volunteers inoculated with genogroup II Norwalk-like viruses (NLVs), Hawaii virus, and Snow Mountain virus and from patients involved in outbreaks of gastroenteritis were tested for genogroup II NLV Mexico virus-specific immunoglobulin M (IgM) by use of a monoclonal antibody, recombinant Mexico virus antigen (rMXV)-based IgM capture enzyme-linked immunosorbent assay (ELISA). Sera from genogroup I Norwalk virus (NV)-inoculated volunteers and from patients involved in a genogroup I NLV outbreak were also tested. In sera from those infected with genogroup I NV or NLVs in volunteer and outbreak studies, only 3 of 25 were rMXV IgM positive; in contrast, 24 of 25 were IgM positive for recombinant NV (rNV). In sera from those infected with genogroup II NLVs in volunteer and outbreak studies, 28 of 47 were rMXV IgM positive and none were IgM positive for rNV, showing the specificity of each IgM test for its respective genogroup. In an outbreak of gastroenteritis not characterized as being of viral etiology but suspected to be due to NV, 7 of 13 persons had IgM responses to rMXV, whereas none had IgM responses to rNV, thus establishing the diagnosis as genogroup II NLV infection. The rMXV-based IgM capture ELISA developed is specific for the diagnosis of genogroup II NLV infections.

Adolescent↗
PubMed1999

Respiratory syncytial virus upregulates expression of the substance P receptor in rat lungs.

Respiratory syncytial virus (RSV) is a major respiratory pathogen in infants. The first goal of this study was to determine whether the infection following endotracheal inoculation of RSV in Fischer 344 rats results in increased inflammatory responses to substance P (SP) either released by capsaicin from sensory nerves or injected into the circulation. Five days after inoculation, the extravasation of Evans blue-labeled albumin after capsaicin or SP was significantly greater in RSV-infected airways than in pathogen-free controls. The peptide-degrading activity of the regulatory enzyme neutral endopeptidase was unaffected by RSV. However, SP(NK(1)) receptor mRNA levels increased fivefold in RSV-infected lungs, and the density of SP binding sites in the bronchial mucosa increased threefold. These data suggest that RSV makes the airways abnormally susceptible to the proinflammatory effects of SP by upregulating SP(NK(1)) receptor gene expression, thereby increasing the density of these receptors on target cells. This effect may contribute to the inflammatory reaction to the virus and could be a target for the therapy of RSV disease and its sequelae.

Animals↗
PubMed1999

Male reproductive toxicity and beta-luteinizing hormone gene expression in sexually mature and immature rats exposed to 2-bromopropane.

1. The reproductive effects of 2-bromopropane (2-BP) in sexually mature and immature male Sprague-Dawley rats were investigated. The animals were randomly divided into three treatment groups and one control group each of which comprised six mature and six immature rats. The treated groups were injected s.c. 200, 600 and 1800 mg/kg of 2-BP on 5 days a week for 5 - 7 weeks and the control group received the vehicle. 2. The absolute and relative testis weights were significantly reduced in 600 and 1800 mg/kg b.w. dose groups in both mature and immature rats. The absolute epididymis, prostate, seminal vesicle, and pituitary weights and the relative epididymis weights, however, were significant only at the highest dose level used in both mature and immature rats. 3. The sperm concentration and sperm viability in epididymal duct decreased and the percentage of abnormal sperm increased in a dose-dependent manner in both mature and immature rats. Additionally, serum testosterone level was significantly decreased in all dose groups in mature rats, and was significantly reduced only in the group treated with the middle and highest dose in immature rats. 4. In both mature and immature rats treated with 200 and 600 mg/kg, the seminiferous tubules were atrophied and all types of germ cells were decreased in number. At the highest dose level, the effect was more marked showing severely atrophied seminiferous tubules and a complete loss of all types of germ cells. 5. The mating, pregnancy and fertility indices were significantly reduced in the 600 and 1800 mg/kg groups. Additionally, at the highest dose group the number of implantations and viable fetuses per litter were reduced and the resorption rate was increased significantly. 6. In the mature rats, the beta-LH gene expression increased significantly in the 1800 mg/kg group when compared to the control group. 7. It can be concluded that 2-BP induces alterations in both neuro-endocrine axis and the reproductive tract under the present experimental conditions. The no observed adverse effect level (NOAEL) in this study could be estimated to be lower than 200 mg/kg/b.w. based on the alteration in testicular morphology as well as on sperm parameters observed at the dose level of 200 mg/kg.

Animals↗
PubMed1999

Fate of Escherichia coli O157:H7 and Salmonella Enteritidis on currency.

The fate of foodborne pathogens Escherichia coli O157:H7 and Salmonella Enteritidis on coin surfaces was determined at room temperature (25 degrees C). A five-strain mixture of E. coli O157:H7 or Salmonella Enteritidis of approximately 5 x 10(4) CFU was applied to the surfaces of sterile U.S. coins (pennies, nickels, dimes, and quarters) and to the surfaces of two control substrata (Teflon and glass coverslips). During storage at room temperature, E. coli O157:H7 survived for 7, 9, and 11 days on the surfaces of pennies, nickels, and dimes and quarters, respectively. However, the pathogen died off within 4 to 7 days on both the Teflon and glass surfaces. Salmonella Enteritidis survived for 1, 2, 4, and 9 days on the surfaces of pennies, nickels, quarters, and dimes, respectively. Unlike E. coli O157:H7, survival of Salmonella Enteritidis was greatest on both Teflon and glass coverslips, with more than 100 cells per substratum detected at the 17th day of storage. Results indicate that coins could serve as potential vehicles for transmitting both E. coli O157:H7 and Salmonella Enteritidis.

Colony Count, Microbial↗
PubMed1999

Cloning and functional expression of the human histamine H3 receptor.

Histamine regulates neurotransmitter release in the central and peripheral nervous systems through H3 presynaptic receptors. The existence of the histamine H3 receptor was demonstrated pharmacologically 15 years ago, yet despite intensive efforts, its molecular identity has remained elusive. As part of a directed effort to discover novel G protein-coupled receptors through homology searching of expressed sequence tag databases, we identified a partial clone (GPCR97) that had significant homology to biogenic amine receptors. The GPCR97 clone was used to probe a human thalamus library, which resulted in the isolation of a full-length clone encoding a putative G protein-coupled receptor. Homology analysis showed the highest similarity to M2 muscarinic acetylcholine receptors and overall low homology to all other biogenic amine receptors. Transfection of GPCR97 into a variety of cell lines conferred an ability to inhibit forskolin-stimulated cAMP formation in response to histamine, but not to acetylcholine or any other biogenic amine. Subsequent analysis revealed a pharmacological profile practically indistinguishable from that for the histamine H3 receptor. In situ hybridization in rat brain revealed high levels of mRNA in all neuronal systems (such as the cerebral cortex, the thalamus, and the caudate nucleus) previously associated with H3 receptor function. Its widespread and abundant neuronal expression in the brain highlights the significance of histamine as a general neurotransmitter modulator. The availability of the human H3 receptor cDNA should greatly aid in the development of chemical and biological reagents, allowing a greater appreciation of the role of histamine in brain function.

Adenylyl Cyclase Inhibitors↗
PubMed1999

[An investigation of the polymorphism of HLA class II alleles in the Han population in Hubei Province of China].

OBJECTIVE: To investigate the polymorphism of HLA class II alleles in the Han population in Hubei province. METHODS: The alleles of DRB1*(n=168), DQB1*(n=160) and DPB1*(n=93) were typed by using the polymerase chain reaction/sequence specific primer(PCR/SSP) and polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) techniques. RESULTS: 39 HLA-DRB1, 15 DQB1 and 17 DPB1 alleles were found. Alleles with higher frequencies are DRB1*0901 (GF=14%), *1501(GF=11.3%), *0301(GF=7.1%), *0803(GF=4.8%); DQB1*0301(GF=18.8%), *0303(GF=18.4%), *0201(GF=10%), *0302(GF=8.4%); DPB1*0501(GF=31.2%), *0401(GF=15.1%), *0201(GF=14%), *0402(GF=11.8%), respectively. As compared with Caucasians, the Han people in Hubei province have higher gene frequencies of DRB1*0901, *1001, *0803; DQB1*0303, *0502 and DPB1*0501, *0202; and lower gene frequencies of DRB1*0301, *0401, *1301; DQB1*0201, *0603 and DPB1*0401, suggesting that Hubei Hans have their own layout of HLA class II allele frequencies. CONCLUSION: These data may serve as normal reference values for the Han population in south China.

Alleles↗
PubMed1999

[Detection of Norwalk and Mexico viruses, two human Caliciviruses in stools of Chilean children].

BACKGROUND: Human calciviruses (HuCVs) cause diarrhea outbreaks associated with consumption of contaminated food and water. Seroepidemiological studies in developing countries, suggest that HuCVs can cause acute gastroenteritis in children. AIM: To study the presence of Norwalk (NV) and Mexico (MX) virus, two HuCVs, in stools of Chilean children from different settings. SUBJECTS AND METHODS: ELISA tests for NV and MX were performed in 677 stool samples for children aged 0 to 132 years old, with acute diarrhea occurring in day care centers or consulting in outpatient clinics or emergency rooms. We also studied eight samples from children involved in a diarrhea outbreak that occurred in a rural community in 1992. A subset of samples was tested with polymerase chain reactions using different primers. RESULTS: Only one sample from a child with acute diarrhea occurring in a day care center was positive for HuCV by polymerase chain reaction. Three samples from the outbreak were positive by the latter method and by ELISA. The HuCV obtained from the day care center was genetically different from other known HuCV. CONCLUSIONS: Despite the high seroprevalence, NV and MX viruses were detected in a very low proportion of Chilean children stools.

Acute Disease↗
PubMed1999

[Down-regulation effect of McAb HIM82 on Ca2+, protein kinase C, protein tyrosine kinase signal pathway of neutrophils].

OBJECTIVES: To study the control effects of HIM82 and HIM70 on reactive oxygen species (ROS) released from respiratory burst of neutrophils (Np), and the action of HIM82 on relevant signal transduction pathway. METHODS: The experimental group (combining with McAb) was compared with the control group with regard to the ROS level, activity of G protein, intracellular [Ca2+] level, the activities of PKC and PTK in activated Np to interpret the mechanism by which the McAb down-regulated the respiratory burst. RESULTS: The positive rate of Np combined with HIM82 was shown over 95% using indirect immunofluorescence assay (control group was 0). The generation of superoxide anion and hydrogen peroxide from PMA-treated Np were decreased by 55% (P < 0.01) and 32% (P < 0.01) with 30 micrograms/ml HIM82. The amount of H2O2 produced in FMLP or SP-stimulated Np were decreased by 16% (P < 0.01) and 37% (P < 0.01) respectively. A similar effect of HIM70 on Np was observed. Furthermore, the inhibition of H2O2 in FMLP-activated Np affected by PT, a specific inhibitor for G-protein, and in HIM82 was 42% and 60% separately, and that with both PT and HIM82 was 85%. It was suggested that HIM82 could enhance the inhibition effect of PT on G-protein. The intracellular [Ca2+] level of Np stimulated with FMLP was decreased by 85%, and that of Np activated with PMA by 100% nearly in the present of HIM82. The activities of PKC and PTK in PMA-stimulated Np were decreased by 23% (P < 0.05) and 35% (P < 0.05) separately when treated with HIM82. CONCLUSION: The McAb HIM82 could down-regulate the ROS produced from activated Np. The mechanism of decreasing ROS may be involved in down-regulating Ca(2+)-PKC and PTK signal transduction pathway activities that are upstream control systems for NADPH oxidase activation.

Antibodies, Monoclonal↗
PubMed1999

[Resection of caudate lobe of liver: report of 26 cases].

OBJECTIVE: To summarize the experience in caudate lobectomy for 26 cases. METHODS: Caudate lobectomy was performed in 26 cases by Peng's multifunctional operative dissector (PMOD) to transect the liver parenchyma (Curettage and Aspiration technique). Primary liver cancer was noted in 18 cases, hilar cholangiocarcinoma in 4, gallbladder carcinoma in 1, right adrenocortical adenocarcinoma in 1, hepatoangioma in 1 and hepatoangiosarcoma in 1. Five cases underwent isolated caudate lobectomy, 1 combined caudate lobectomy with right trisegmentectomy, 6 combined caudate lobectomy with right hemihepatectomy, 9 combined caudate lobectomy with left hemihepatectomy, and 5 combined caudate lobectomy with segmentectomy. RESULTS: The operations were carried out successfully. Follow up for 2 - 23 months, 1 case died from pulmonary infraction 2 weeks after operation, 1 died from lung metastasis 2 months after operation, 10 died from tumor recurrence or metastasis 3, 11, 12, 15, 15, 15, 15, 19, 30, 30 months after operation respectively. The other 14 cases are still alive for 2 to 18 months. CONCLUSIONS: With PMOD, it is possible to dissect the structure precisely. Therefore the caudate lobe can be isolated from the three porta hepatis without much difficulty. Caudectomy can be performed safely.

Adult↗
PubMed1999

[Sex hormone receptor of hemangioma and vascular malformation in children].

OBJECTIVE: To investigate the level and difference of estrogen receptor (ER), progestogen receptor (PR) and androgen receptor (AR) in hemangioma tissues of Children. METHODS: 31 specimens of hemangioma and 36 specimens of vascular malformation were compound stained with hematoxylin-eosin and enzyme-linking affinitive immunohistochemistry. The prepared tissue slices were examined microscopically to find the ER, PR and AR in all the cells. RESULTS: The ER, PR and AR were detected in the two kinds of the tissue. However, their levels in the hemangioma were higher than those in the vascular malformation (P < 0.01) and the levels in the hemangioma of proliferating phase were higher than those in the hemangioma of regressive phase (P < 0.01). CONCLUSIONS: Hemangioma is one of the target tissues of estrogen. ER, PR and AR play an important role in the growth and development of hemangiomas. The binding site of the receptor may be occupied by extrogenous glucocorticoid so that hemangiomas gradually degenerates.

Adolescent↗