Biomedical subjects

Hui Li

Publications and source records attributed to Hui Li.

At least 91 records · Page 5Linked to original sources

PubMed2006

Challenges in the control of gonorrhea in South America and the Caribbean: monitoring the development of resistance to antibiotics.

OBJECTIVE: : The objective of this study was to ascertain the antimicrobial susceptibility of Neisseria gonorrhoeae isolates from 6 South American and 13 Caribbean countries participating in the Gonococcal Antimicrobial Surveillance Program (GASP) from 1990 to 1999. STUDY: : A GASP network of laboratories was launched in the Americas and the Caribbean during the 1990s. Standardized methods and interpretative criteria were established for the isolation of N. gonorrhoeae, strain identification, and determination, and quality control of antimicrobial susceptibility. RESULTS: : Two countries (Argentina and Uruguay) maintained continuous surveillance during the study period. Some countries gathered data periodically and several others were unable to initiate antimicrobial surveillance as a result of lack of resources. The percentage of penicillin-resistant N. gonorrhoeae isolated in the region over the decade varied considerably (1.0-11.9% carried chromosomal resistance and 17.9-38.8% produced beta-lactamase) with an overall trend to declining numbers of penicillin-resistant isolates. For tetracycline, 7.4% to 36.3% carried chromosomal resistance, whereas 12.0% to 27.4% carried plasmid-mediated resistance. There were no reports of ciprofloxacin-resistant isolates, although N. gonorrhoeae with decreased susceptibility to ciprofloxacin and azithromycin as well as spectinomycin-resistant isolates were identified in some countries.

Anti-Bacterial Agents↗

PubMed2006

Herpes simplex virus 1 infection induces the expression of proinflammatory cytokines, interferons and TLR7 in human corneal epithelial cells.

Herpetic epithelial and stromal keratitis is a sight-threatening ocular infection. To study the role of the epithelium in the innate response to herpes simplex virus 1 (HSV-1) infection of the cornea, we used a telomerase-immortalized human corneal epithelial cell (HCEC) line, HUCL, and primary HCECs as a model and infected the cells with HSV-1 (KOS strain). HSV-1 infection of HCECs resulted in a two-phase activation of nuclear factor-kappaB (NF-kappaB), JNK and p38, with the first peak at 1-4 hr and a second peak at 8 hr. Concomitant with the first peak of activation, transcriptional expression of interleukin (IL)-6, IL-8, tumour necrosis factor (TNF)-alpha and interferon (IFN)-beta was rapidly induced in HSV-1-infected cells. HSV-1 infection also induced the production of IL-6, IL-8, and TNF-alpha in both HUCL cells and primary HCECs. Coincident with the second phase of NF-kappaB activation in HSV-1-infected HCECs, the expression of Toll-like receptor 7 (TLR7) was induced, whereas the level of TLR3 was greatly down-regulated. Thus, in response to HSV-1 infection, HCECs produce proinflammatory cytokines, leading to infiltration, and IFNs to enhance the antiviral activity in the cornea, probably through sequential activation of TLRs.

Cells, Cultured↗

PubMed2006

Aldose reductase regulates TGF-beta1-induced production of fibronectin and type IV collagen in cultured rat mesangial cells.

AIM: To study the effects of aldose reductase (AR) on production of fibronectin and type IV collagen in rat mesangial cells (MsC). METHODS: The vector, pcDNA3-AR, was constructed based on pET-15b-AR. Lipofect AMINE was used for stable transfection and G418 was used for selecting positive clones. Sorbinil and zopolrestat were added for suppressing the activity of AR, respectively. The production of fibronectin and type IV collagen and the activation of Smads and MAPK signal transduction pathway were analysed by western blot and AP-1 activity was analysed by electrophoretic mobility shift assays (EMSA). RESULTS: The normal MsC showed increased expression of fibronectin and type IV collagen with stimulation of TGF-beta1. Compared with the normal MsC, the MsC pre-incubated with ARI showed reduced expression (P < 0.05) and the AR-transfected MsC showed increased expression (P < 0.05). The normal MsC showed activation of ERK, JNK and p38 with stimulation of TGF-beta1, while the activation of JNK and p38 was inhibited in the MsC pre-incubated with ARI and only the activation of JNK was enhanced in the AR-transfected MsC. The normal MsC showed enhanced AP-1 activity with the stimulation of TGF-beta1, and similarly the activity was inhibited in the MsC pre-incubated with ARI and was more enhanced in the AR transfected MsC. CONCLUSION: AR can regulate the expression of fibronectin and type IV collagen with the stimulation of TGF-beta1 in MsC, which may have relations with the activation of JNK-MAPK and p38-MAPK signalling pathways and AP-1.

Aldehyde Reductase↗

PubMed2006

Longitudinal profile of antibodies against SARS-coronavirus in SARS patients and their clinical significance.

BACKGROUND: Severe acute respiratory syndrome (SARS) is a newly discovered disease caused by a novel coronavirus. The present study studied the longitudinal profile of antibodies against SARS-coronavirus (SARS-CoV) in SARS patients and evaluated the clinical significance of these antibodies. METHODS: Two methods, ELISA and indirect immunofluorescent assay, were used for the detection of the anti-SARS-CoV IgG and IgM in 335 serial sera from 98 SARS patients. In 18 patients, serum antibody profiles were investigated and antibody neutralization tests were performed from 7 to 720 days after the onset of symptoms. RESULTS: The ratios of positive IgG/IgM by ELISA were 0/0, 45.4/39.4, 88.6/71.4, 96/88, 100/48.6, 100/30.9, 100/17.1, 100/0 per cent, respectively, on 1-7, 8-14, 15-21, 22-28, 29-60, 61-90, 91-180 and 181-720 days after the onset of symptoms. Antibodies were not detected within the first 7 days of illness, but IgG titre increased dramatically on day 15, reaching a peak on day 60, and remained high until day 180 from when it declined gradually until day 720. IgM was detected on day 15 and rapidly reached a peak, then declined gradually until it was undetectable on day 180. Neutralizing viral antibodies were demonstrated in the convalescence sera from SARS patients. CONCLUSION: The persistence of detectable IgG antibodies and neutralizing viral antibodies for up to 720 days suggest that SARS patients may be protected from recurrent SARS-CoV infection for up to 2 years.

Adult↗

PubMed2006

Molecular analysis of the bacterial community in a continental high-temperature and water-flooded petroleum reservoir.

Water from a continental high-temperature, long-term water-flooded petroleum reservoir in Huabei Oilfield in China was analysed for its bacterial community and diversity. The bacteria were characterized by their 16S rRNA genes. A 16S rRNA gene clone library was constructed from the community DNA, and using restriction fragment length polymorphism analysis, 337 randomly selected clones were clustered with 74 operational taxonomic units. Sequencing and phylogenetic analyses showed that the screened clones were affiliated with Gammaproteobacteria (85.7%), Thermotogales (6.8%), Epsilonproteobacteria (2.4%), low-G+C Gram-positive (2.1%), high-G+C Gram-positive, Betaproteobacteria and Nitrospira (each <1.0%). Thermopilic bacteria were found in the high-temperature water from the flooded petroleum reservoir, as well as mesophilic bacteria such as Pseudomonas-like clones. The mesophilic bacteria were probably introduced into the reservoir as it was being exploited. This work provides significant information on the structure of bacterial communities in high-temperature, long-term water-flooded petroleum reservoirs.

Bacteria↗

PubMed2006

Diverse phenotype of Brooke-Spiegler syndrome associated with a nonsense mutation in the CYLD tumor suppressor gene.

Brooke-Spiegler syndrome (BSS) is an autosomal dominant disease characterized by cylindromas, trichoepitheliomas and occasionally spiradenomas. The disease gene was mapped to 16q12-13, and mutations in the CYLD gene were identified in families with BSS. In the present report, we describe a large consanguineous Chinese family with BSS showing an intra-family phenotypic variability. Clinically, some affected individuals only revealed discrete small skin-coloured tumors whereas the proband showed an expansion of multiple large tumors on the back of nose and numerous dome-shaped papules on her scalp. Histologically, both trichoepitheliomas and cylindromas were found in the affected individuals. By sequence analysis, we identified a recurrent mutation 2272C>T (R758X) of the CYLD gene in the affected individuals of this family, which was previously identified in other ethnic families with familial cylindromatosis. Our result provided additional information for phenotype-genotype correlation in BSS.

Adult↗

PubMed2006

Residue Phe266 in S5-S6 loop is not critical for Charybdotoxin binding to Ca2+-activated K+ (mSlo1) channels.

AIM: To gain insight into the interaction between the Charybdotoxin (ChTX) and BK channels. METHODS: Site-directed mutagenesis was used to make two mutants: mSlo1-F266L and mSlo1-F266A. The two mutants were then expressed in Xenopus oocytes and their effects were tested on ChTX by electrophysiology experiments. RESULTS: We demonstrate an equilibrium dissociation constant Kd=3.1-4.2 nmol/L for both the mutants mSlo1-F266L and mSlo1-F266A similar to that of the wild-type mSlo1 Kd=3.9 nmol/L. CONCLUSION: The residue Phe266 does not play a crucial role in binding to ChTX, which is opposed to the result arising from the simulation of peptide-channel interaction.

Amino Acid Sequence↗

PubMed2006

Genetic and epigenetic alterations of DLC-1, a candidate tumor suppressor gene, in nasopharyngeal carcinoma.

The DLC-1 gene, located at the human chromosome region 8p22, behaves like a tumor suppressor gene and is frequently deleted in diverse tumors. The deletion of 8p22 is not an uncommon event in nasopharyngeal carcinoma (NPC), therefore we explored the expression levels of the DLC-1 gene in NPCs and NPC cell lines by reverse transcription-polymerase chain reaction. The results showed the mRNA level of DLC-1 was downregulated. To identify the mechanism of DLC-1 downregulation in NPC, we investigated the methylation status of the DLC-1 gene using methylation-specific PCR, and found that 79% (31 of 39) of the NPC tissues and two DLC-1 nonexpressing NPC cell lines, 6-10B and 5-8F, were methylated in the DLC-1 CpG island. Microsatellite PCR was also carried out, and loss of heterozygosity was found at four microsatellite sites (D8S552, D8S1754, D8S1790 and D8S549) covering the whole DLC-1 gene with ratios of 33% (4 of 12 informative cases), 18% (2 of 11), 5% (1 of 18), and 25% (3 of 12), respectively. Taken together, our results suggest that DLC-1 might be an NPC-related tumor suppressor gene affected by aberrant promoter methylation and gene deletion.

Adult↗

PubMed2006

Vascular basement membrane-derived multifunctional peptide, a novel inhibitor of angiogenesis and tumor growth.

Vascular basement membrane-derived multifunctional peptide (VBMDMP) gene (fusion gene of the human immunoglobulin G3 upper hinge region and two tumstatin-derived fragments) obtained by chemical synthesis was cloned into vector pUC19, and introduced into the expression vector pGEX-4T-1 to construct a prokaryotic expression vector pGEX-4T-1-VBMDMP. Recombinant VBMDMP produced in Escherichia coli has been shown to have significant activity of antitumor growth and antimetastasis in Lewis lung carcinoma transplanted into mouse C57Bl/6. In the present study, we have studied the ability of rVBMDMP to inhibit endothelial cell tube formation and proliferation, to induce apoptosis in vitro, and to suppress tumor growth in vivo. The experimental results showed that rVBMDMP potently inhibited proliferation of human endothelial (HUVEC-12) cells and human colon cancer (SW480) cells in vitro, with no inhibition of proliferation in Chinese hamster ovary (CHO-K1) cells. rVBMDMP also significantly inhibited human endothelial cell tube formation and suppressed tumor growth of SW480 cells in a mouse xenograft model. These results suggest that rVBMDMP is a powerful therapeutic agent for suppressing angiogenesis and tumor growth.

Angiogenesis Inhibitors↗

PubMed2006

Identification of genes related to nasopharyngeal carcinoma with the help of pathway-based networks.

cDNA microarray is a powerful tool to analyze simultaneously the expression levels of tens of thousands of genes. Compared with normal nasopharynx (NP) tissues, 2210 genes were highly differentially expressed in nasopharyngeal carcinoma (NPC) tissues detected by cDNA microarray. Since signal pathway is widely used to describe the complex relationship between genes, a pathway-based network was constructed to visualize the connection between the genes obtained from microarray data in this report. We analyzed the targeted genes that may have more important influence on this gene network with statistical methods and found that some genes might have significant influence on this network, especially Ras-related nuclear protein (RAN), carboxyl ester lipase (CEL), v-rel reticuloendotheliosis viral oncogene homolog A (RELA) genes. To verify the results from pathway-based selection, reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR were performed to detect the expression levels of RAN, CEL and RELA genes and it was found that the RAN and CEL genes were significantly up-regulated in more than 80% of NPC tissues. To further elucidate the function of the RAN gene, RAN expression was specifically suppressed in a 5-8F NPC cell line by RNA interference (RNAi). As expected, the depletion of RAN could effectively block the proliferation of tumor cells. Therefore, our study may open up a new way to analyze the vast microarray data.

Base Sequence↗

PubMed2006

Identification of a CRYAB mutation associated with autosomal dominant posterior polar cataract in a Chinese family.

PURPOSE: A four-generation Chinese family with 13 members affected with autosomal dominant congenital posterior polar cataract was studied. The purpose of this study was to identify the disease-causing gene in the family and to validate that mutations in CRYAB, the alphaB-crystallin gene, cause the congenital cataract. METHODS: Linkage analysis was performed with a panel of microsatellite markers flanking candidate genetic loci for cataracts, including 14 known autosomal dominant congenital cataract (ADCC) genes. For mutation analysis, the complete coding region and exon-intron boundaries of CRYAB were sequenced with DNA from the proband. Single-strand conformation polymorphism (SSCP) analysis for exon 1 of CRYAB was performed in all family members and 200 normal control subjects. RESULTS: The disease gene in the Chinese family was mapped to chromosome 11 in region q22-22.3 with a maximum lod score of 4.52. Direct DNA sequence of CRYAB revealed a heterozygous C-->T transition at nucleotide 58, resulting in a novel 58 C-->T (Pro20Ser) mutation. The Pro20Ser mutation cosegregated with all affected individuals and was not present in unaffected members in the family or in 200 normal control subjects. The mutation occurs at the evolutionarily conserved residue Pro20 in the N-terminal region of alphaB-crystallin. CONCLUSIONS: To date, only one CRYAB mutation has been associated with congenital isolated cataract. This study identified a second novel mutation in CRYAB in a large Chinese cataract family. Together, these results provide strong evidence that CRYAB is a pathogenic gene for congenital cataract.

Aged↗

PubMed2006

Low-density lipoprotein nanoparticles as magnetic resonance imaging contrast agents.

Low-density lipoproteins (LDLs) are a naturally occurring endogenous nanoplatform in mammalian systems. These nanoparticles (22 nm) specifically transport cholesterol to cells expressing the LDL receptor (LDLR). Several tumors overexpress LDLRs presumably to provide cholesterol to sustain a high rate of membrane synthesis. Amphiphilic gadolinium (Gd)-diethylenetriaminepentaacetic acid chelates have been incorporated into the LDL to produce a novel LDLR-targeted magnetic resonance imaging (MRI) contrast agent. The number of Gd chelates per LDL particle ranged between 150 and 496 Gd(III). In vitro studies demonstrated that Gd-labeled LDL retained a similar diameter and surface charge as the native LDL particle. In addition, Gd-labeled LDL retained selective cellular binding and uptake through LDLR-mediated endocytosis. Finally, Gd-labeled LDLs exhibited significant contrast enhancement 24 hours after administration in nude mice with human hepatoblastoma G2 xenografts. Thus, Gd-labeled LDL demonstrates potential use as a targeted MRI contrast agent for in vivo tumor detection.

Animals↗

PubMed2006

Triazine adsorption by saponite and beidellite clay minerals.

We investigated the sorption of three triazine herbicides (atrazine, simazine, and metribuzin) by saponite and beidellite clay minerals saturated with K+, Cs+, Na+, and Ca2+. Saponite clay sorbed a larger fraction of each pesticide from aqueous solution than did beidellite clay. The lower cation-exchange capacity in saponite compared to that in beidellite presumably results in a less crowded interlayer, with more siloxane surface being available for adsorption. Generally, Cs-saturated clays sorbed more triazines than did clays saturated by K+, Na+, or Ca2+. We attribute this to the smaller hydrated radius of Cs+, which again increases the siloxane surface that is available for sorption. Furthermore, the relatively weak hydration of Cs+ reduces the swelling of clay interlayers, thus making sorption domains less hydrated and more receptive to hydrophobic molecules. The Cs-saponite manifested a sorption of more than 1% atrazine by weight above equilibrium concentrations of 6 mg/L, which to our knowledge is the largest sorption of neutral atrazine from water yet reported for an inorganic sorbent. Molecular dynamics simulations indicate that atrazine interacts both with clay basal planes and with multiple cations in the clay interlayer.

Adsorption↗

PubMed2006

[Kinetic turbidimetric limulus assay of bacterial endotoxin in the replacement solution of on-line hemodiafiltration].

OBJECTIVE: To determine bacterial endotoxin in the replacement solution of on-line hemodiafiltration (on-line HDF) using kinetic turbidimetric limulus test. METHODS AND RESULTS: Validation test was performed with the replacement solution of on-line HDF in which quantified standard endotoxin was added. The recovery rates of endotoxin from the replacement solution and its dilutions at 1/5, 1/10, and 1/20 were 58.17%, 106.7%, 99.00% and 98.79%, respectively, suggesting that the optimal dilution was at 1/10. Standard endotoxin was added into the replacement solution of on-line HDF of 3 batches (040408, 040511,040527), and the recovery rates in their dilution at 1/10 were 76.32%, 99.00% and 96.24%, respectively. The standard endotoxin in the working curve was 1.00, 0.125, and 0.0156 Eu/ml (endotoxin unit/ml), and the dilution at 1/10 of the replacement solution is effective to eliminate the interference in limulus test. CONCLUSION: Kinetic turbidimetric limulus test provide a means to detect endotoxin in the replacement solution of on-line HDF.

Endotoxins↗

PubMed2006

[Regulation of fat metabolism by PPARs].

Peroxisome proliferator activated receptors (PPARs) belong to the nuclear receptor superfamily. PPARs have diverse biological functions such as enhancing insulin sensitivity, regulating saccharometabolism homeostasis, and especially regulation of lipid homeostasis, which is the focus of much of the researches at present. In this article, we summarize the regulation of fat metabolism by PPAR genes based on their structure, function and expression.

Animals↗

PubMed2006

[Clinicopathological analysis of biliary tract complications on post-liver transplantation patients].

OBJECTIVE: To analyze the pathohistological changes of the livers and the clinical features of patients with biliary tract complications after their orthotopic liver transplantations. METHODS: From Sept 1998 to June 2005 clinical and pathological data of 173 post-liver transplantation patients with biliary tract complications were analyzed. RESULTS: Biliary tract complications occurred within 3-2920 days after the transplantation operations. These complications occurred within 1-30 days, 31-90 days, 91-180 days, 180 days at rates of 49.71%, 17.92%, 4.62%, 27.74% respectively. The complications were of inflammatory nature in 171 cases, (72.25%), and of obstructive nature in 164 cases (27.74%). The main pathological changes were epithelium degeneration of interlobular bile ducts, inflammatory cell infiltration in portal areas, proliferation of interlobular bile ducts, fibrosis in portal areas, cholestasis in small bile ducts and hepatocytes. CONCLUSION: Many of the biliary tract complications of post-liver transplantation in our cases were of inflammatory nature and they often occurred within 30 days after the surgery. Obstructive nature complications often occurred in 90 days after the surgery and the prognosis of these cases was much poorer. The pathological changes of live tissues shown in liver biopsies are important for prognostic evaluation, differential diagnosis and categorization of biliary tract complications.

Adolescent↗

PubMed2006

[Management of corneo-conjunctival malignant melanoma with "no touch technique" surgical excision and corneoscleral lamellar keratoplasty].

OBJECTIVE: To study the management of "no touch technique" surgical excision and corneoscleral lamellar keratoplasty in the treatment of corneo-conjunctival malignant melanoma. METHODS: Surgical excision for corneo-conjunctival malignant melanoma in six cases, from October 1989 to January 2004 in Zhongshan Ophthalmic Center, were performed. The entire tumors were removed in one piece without touching the tumor (no touch technique). The incision was outlined 4-6 mm outside the pigmented conjunctival mass, and 2 mm outside the corneal component. Dissecting deep enough without any tumor cell left to yield a tumor-free bed. After surgical incision, the host eyeball defect was covered with partial or total corneoscleral lamellar graft from fresh donor, and the conjunctiva defect was covered with or without amniotic membrane transplantation. All the patients were followed up to 6 months. RESULTS: The tumors in the remaining conjunctival margins were completely removed by local dissection combined with cryotherapy in the six cases. Three cases were treated with partial corneoscleral lamellar keratoplasty, two cases with total corneoscleral lamellar keratoplasty and one case with total corneoscleral lamellar keratoplasty plus amniotic membrane transplantation. All cases were subsequently treated with 0.01% thiotepa eyedrops and supplemental dacarbazine chemotherapy. At the average 43.5 months follow-up time (14.6 years to 6 months), no evidences of local recurrence of malignant melanoma or distant metastasis were observed. CONCLUSION: The clinical study suggests that using surgical excision of "no touch technique" to remove tumor in whole piece with corneoscleral lamellar keratoplasty is effective in the treatment of corneo-conjunctival malignant melanoma.

Adult↗

PubMed2006

[Linkage analysis of the polymorphism at D17S1878 site with essential hypertension].

OBJECTIVE: To explore the linkage of the polymorphism at D17S1878 site with susceptible gene of essential hypertension. METHODS: Forty-five pedigrees from the high prevalence region of the hypertension were collected. The polymorphism of D17S1878 site was genotyped with genetic analyzer and gene-scan software. Discordant sib pair analysis and affected sib pair analysis were used in linkage analysis. RESULTS: There were significant differences in the age, male, alcohol-consuming, over-salt intake, average systolic pressure, average diastolic pressure, waist-to-hip-ratio, total cholesterol, high-density lipoprotein, and low density lipoprotein between the hypertensive sib and the normotensive sib (P < 0.05). There were eleven alleles at D17S1878 site, and the allele frequency was significantly different between the hypertensive and normotensive sibs (P < 0.05). Forty-three pedigrees were analyzed with affected sib pair analysis (t = 3.05, P < 0.05). CONCLUSION: The polymorphism of D17S1878 may be linked with susceptible genes of essential hypertension.

Adolescent↗