Biomedical subjects

Li Rong

Publications and source records attributed to Li Rong.

7 recordsLinked to original sources

PubMed2006

Determination of iodide in seawater samples by ion chromatography with chemically-bonded poly(ethylene glycol) stationary phase.

An ion chromatographic method for the rapid and direct determination of iodide in seawater is reported. Poly(ethylene glycol) (PEG) groups were chemically bonded onto silica gel or C30-bonded silica gel via diol groups. PEG-bonded C30 binary phases allowed determination of iodide in seawater samples without any interference. Effects of eluent composition on retention behavior of inorganic anions have been investigated. Both cation and anion of the eluent affected the retention of analyte anions. The retention time of anions increased with increasing eluent concentration. The detection limit for iodide obtained by injecting 0.2 microl of sample was 13 microg l(-1) (S/N=3) while the limit of quantitation was 43 microg l(-1) (S/N=10). The present method was successfully applied to the rapid and direct determination of iodide in seawater with long-term durability.

Chromatography, Ion Exchange↗

PubMed2005

Comparative and functional genomic analyses of the pathogenicity of phytopathogen Xanthomonas campestris pv. campestris.

Xanthomonas campestris pathovar campestris (Xcc) is the causative agent of crucifer black rot disease, which causes severe losses in agricultural yield world-wide. This bacterium is a model organism for studying plant-bacteria interactions. We sequenced the complete genome of Xcc 8004 (5,148,708 bp), which is highly conserved relative to that of Xcc ATCC 33913. Comparative genomics analysis indicated that, in addition to a significant genomic-scale rearrangement cross the replication axis between two IS1478 elements, loss and acquisition of blocks of genes, rather than point mutations, constitute the main genetic variation between the two Xcc strains. Screening of a high-density transposon insertional mutant library (16,512 clones) of Xcc 8004 against a host plant (Brassica oleraceae) identified 75 nonredundant, single-copy insertions in protein-coding sequences (CDSs) and intergenic regions. In addition to known virulence factors, full virulence was found to require several additional metabolic pathways and regulatory systems, such as fatty acid degradation, type IV secretion system, cell signaling, and amino acids and nucleotide metabolism. Among the identified pathogenicity-related genes, three of unknown function were found in Xcc 8004-specific chromosomal segments, revealing a direct correlation between genomic dynamics and Xcc virulence. The present combination of comparative and functional genomic analyses provides valuable information about the genetic basis of Xcc pathogenicity, which may offer novel insight toward the development of efficient methods for prevention of this important plant disease.

Bacterial Proteins↗

PubMed2005

The design and application of DNA chips for early detection of SARS-CoV from clinical samples.

BACKGROUND: SARS coronavirus has been identified as the cause of severe acute respiratory syndrome (SARS). Few tests allow confirmation or exclusion of SARS within the first few days of infection. A gene chip is a useful tool for the study of microbial infections mainly for its capability of performing multi-target analysis in a single test. OBJECTIVES: Investigate the possibility of early detection of SARS virus from clinical samples using the gene chip-based method. STUDY DESIGN: We purified RNA from SARS-CoV obtained from routinely collected peripheral blood and sputum samples of 34 patients who had been identified as probable SARS patients by following the interim U.S. case definition. Four segments of the SARS-CoV were amplified using reverse transcription-nested PCR and the products examined using the 70-mer gene chips for SARS-CoV detection. RESULTS: A blind-test of both peripheral blood and sputum specimens lead to the positive detection of SARS-CoV in 31 out of 34 patients. SARS-CoV was not found in peripheral blood or sputum specimens from three patients. Two of the 34 patients were only 3 days post-onset of symptoms and were subsequently confirmed to be SARS positive. Our results indicate that the gene chip-based molecular test is specific for SARS-CoV and allows early detection of patients with SARS with detection rate about 8% higher than the single PCR test when the sputum sample is available.

Blood↗

PubMed2005

Decrease of CD4+ T-lymphocytes in children exposed to environmental lead.

The effects of environmental lead on the immune system of young children were assessed by determining the peripheral blood lymphocytes CD3+, CD4+, CD8+, B(CD19+) counts, and natural killer (CD16+CD56+) cells in 35 preschool children whose mean blood lead level was 140.6 microg/L. The results were compared to an age- and sex-matched control group with a mean blood lead level of 64.3 microg/L. Compared to the controls, a significant reduction in the percentage of CD4+ cells and a significant increase of CD8+ cells were seen in the high-lead group. The negative correlation between the percentage of CD4+ cells and blood lead levels was found to be significant (p<0.01). These results suggest that exposure to environmental lead might result in alterations in the immune function of young children.

Antigens, CD19↗

PubMed2004

Determination of iodide in seawater and edible salt by microcolumn liquid chromatography with poly(ethylene glycol) stationary phase.

An ion chromatography method for rapid and direct determination of iodide in seawater and edible salt is reported. Separation was achieved using a laboratory-made C30 packed column (100 mm x 0.32 mm i.d.) modified with poly(ethylene glycol) (PEG). Effects of eluent composition on retention behavior of inorganic anions have been investigated. Both cation and anion of the eluent affected the retention of analyte anions. The retention time of anions increased with increasing eluent concentration when lithium chloride, sodium chloride, potassium chloride, sodium sulfate, magnesium sulfate were used as the eluent, while it decreased with increasing eluent concentration when ammonium sulfate was used as the eluent. The detection limit for iodide obtained by injecting 0.2 microl of sample was 9 microg/l (S/N = 3). The present method was successfully applied to the rapid and direct determination of iodide in seawater and edible salt samples. Partition may be involved in the present separation mode.

Acetonitriles↗

PubMed2003

Increased adherence to Caco-2 cells caused by disruption of the yhiE and yhiF genes in enterohemorrhagic Escherichia coli O157:H7.

Adherence of enterohemorrhagic Escherichia coli (EHEC) to intestinal epithelium is essential for initiation of infections, including diarrhea, and expression of the genes of the locus of enterocyte effacement (LEE) is thought to be crucial for adherence. To identify genes involved in modulating the adherent capacity, bacteria collected from an EHEC O157:H7 strain (O157Sakai) mutagenized by mini-Tn5Km2 were screened for their ability to increase the number of microcolonies (MC) on Caco-2 cells and eight mutants with increased adherence were isolated. Analysis of the mini-Tn5Km2-flanked DNA sequences indicated that one possessed the insertion within an O157 antigen gene cluster, another possessed the insertion within the yhiF gene, and the remaining six mutants had their insertions in the yhiE gene. yhiE and yhiF products share amino acid homology (23% identity) to each other and with members of the LuxR family, which are known as transcriptional regulatory proteins. The mutant having the insertion within the O157 antigen gene cluster did not express the O157 side chain (as determined by agglutination test and immunoblotting with polyclonal O157-specific antiserum), unlike the other seven mutants. Importantly, the other mutants showed enhanced type III secretion. Levels of the related mRNAs of genes of the LEE, but not that of ler mRNA, were also increased compared with those in the wild type. Indeed, when we introduced an in-frame deletion into the yhiE or yhiF gene in O157Sakai, the capacity of the resultant mutants to adhere to Caco-2 cells was greatly increased. When one of the yhiE insertion mutants was orally inoculated into ICR mice, the number of bacteria shed into feces by day 14 was greater than that for the wild type. These results suggest that yhiE and yhiF are involved in the adherence of O157Sakai to epithelial cells as negative regulators for the expression of the genes required for the type III secretion system.

Animals↗

PubMed2003

[Observation on efficacy of CT positioning scalp circum-needling combined with Chinese herbal medicine in treating poly-infarctional vascular dementia].

OBJECTIVE: To observe the short-term effect of patients with poly-infarctional vascular dementia (PIVD) treated by CT positioning scalp circum-needling (SCN) combined with Chinese herbal medicine. METHODS: Eighty-nine patients of PIVD were enrolled and divided into the treated group (n = 57) and the control group (n = 32). They were all treated with oral taking of Fuyuan mixture (FYM, consisted of ginseng, medlar, salvia, bitter cardamon, etc). To the treated group, SCN was applied additionally with the unilateral area around the reflecting region (localized by CT) in scalp as main needling points and Ganshu, Shenshu, Zusanli, Hegu as supplementary points. Two courses of SCN were performed. The changes of clinical symptoms, intelligence and hemorrheological characteristics in patients were analysed. RESULTS: After two courses of treatment, the total effective rate in the treated group was 96.5%, which was better than that in the control group (75.0%), with significant difference (u = 2.423, P < 0.01); HDS scores increased in both groups after treatment, showing significant difference as compared with that before treatment (P < 0.01), hemorrheologic parameters were also apparently improved. CONCLUSION: CT positioning SCN combined Chinese herbal medicine treatment has definite therapeutic effect in treating PIVD.

Acupuncture Therapy↗