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Biomedical subjects

Nan Li

Publications and source records attributed to Nan Li.

At least 127 records · Page 7Linked to original sources
PubMed2003

Colorectal cancer screening for the natural population of Beijing with sequential fecal occult blood test: a multicenter study.

OBJECTIVE: To assess the prevalence of colorectal cancer (CRC) in Beijing and the reliability of the sequential fecal occult blood test (SFOBT) for CRC screening. METHODS: Of the natural population (48 100 persons) in several Beijing communities, we screened 26 827 persons with age over 30 using the SFOBT screening program, Guaiacum Fecal Occult Blood Test (GFOBT), Immuno Fecal Occult Blood Test (IFOBT), and colonoscopies. RESULTS: The screening rate of the population was 74%. The positive rate of SFOBT was 5.6%. The prevalence of CRC in the entire population of Beijing was therefore calculated to be 36.57/10(5). Of 12 CRC detected patients, 4 cases were in stage Dukes A (33.33%), 7 cases in stage Dukes B (58.33%), only 1 case (8.34%) in stage Dukes C. CONCLUSIONS: The prevalence of CRC in Beijing is one of the highest in China. Individuals at high risk for CRC or those over 50 years of age should be considered as primary candidates for screening. SFOBT screening is a cost-effective and reliable method for early detection of CRC.

Adult↗
PubMed2003

[Population-based study of human papillomavirus infection in high-risk area for cervical cancer in Shanxi Province, China].

OBJECTIVES: To investigate the prevalence of oncogenic type of human papillomavirus (HPV) infection and identify the high risk population for conducting immuno/chemoprevention of cervical cancer. METHODS: All married women aged 30 to 50 with no history of hysterectomy, pelvic radiation and non-pregnant from certain villages of Xiangyuan and Yangcheng County were invited. This study was conducted through two phases. In phase one, subjects sampled the vaginal secretions using the collectors after signing the informed consent. And physicians sampled exfoliated cells from cervix in the phase two. All the specimens were tested with the Hybrid Capture 2 test. The data was managed and analyzed by VFP and SPSS software. RESULTS: There were 9,683 women participated in this study. Local women welcomed this study and population compliance rate was 75.4%. In tested population, we found 2,666 subjects of HPV DNA positive and HPV prevalence was 27.5%. The rates of different age group were 24.5% (30-34 yrs), 27.4% (35-39 yrs), 28.2% (40-44 yrs), 27.4% (45-50 yrs) respectively and had no significant differences (P = 0.604). The rates were slightly increased with the higher education level and had no differences (P = 0.106). The rate in mountain areas was higher than that in half-mountain areas (P = 0.001). CONCLUSIONS: The prevalence of HPV infection is indeed high in this region. Local women and health professionals welcome the activities of cervical cancer screening and prevention. It is an emergent task to improve their sanitary condition and prevent them from cervical cancer in these women. A women health cohort is established successfully among high HPV exposed women in rural China. The extensive biologic specimen repository has been successfully established to simultaneously study the etiology, early detection, and immuno/chemoprevention of cervical cancer.

Adult↗
PubMed2003

[A case report of cystic fibrosis and review of 16 cases of cystic fibrosis in Chinese patients].

OBJECTIVE: To report a case of cystic fibrosis (CF) in a Chinese and to review the clinical features, gene mutations, diagnosis and outcome of CF in Chinese patients. METHODS: A 14-year-old Chinese girl presenting with recurrent productive cough since birth with parasinusitis and otitis media was confirmed to have CF in Peking University First Hospital. Chest CT scan showed bronchiectasis, more severe in the right upper lobe. Sweat tests were taken three times, and the values of Na(+) and Cl(-) were (126.6 +/- 5.4) mmol/L and (108.9 +/- 3.3) mmol/L, respectively. The examination of the pancreas showed no remarkable cystic changes on CT scan and there was no pancreatic insufficiency. Sixteen patients with CF in Chinese reported from 1974 to 1999 were reviewed. RESULTS: Sixteen of the 17 patients (7 males and 9 females, aged from 6 months to 25 years) had clinical data available for analysis. Eleven of them had died, nine before the age of 13. They all suffered from frequent episodes of pneumonia, while 14 had malnutrition and 4 had jaundice. The diagnostic procedures included clinical features, sweat test and autopsy. Four of them had DNA screened and four kinds of novel mutations in the cystic fibrosis transmembrane conductance regulator gene were found. CONCLUSIONS: Chinese patients with CF show similar clinical manifestations to patients in the European and North American populations, but the CFTR mutation was different.

Adolescent↗
PubMed2003

[Value of acetic acid smear test for cervical cancer screening].

BACKGROUND & OBJECTIVE: At present, the incidence of cervical cancer is still high in less developed areas of China; one of the reasons is that cytology in screening for cervical cancer is not feasible in these areas. The aim of this study was to analyze the sensitivity and specificity of acetic acid smear test as a cervical cancer screening test, and evaluate the value of this method for cervical cancer screening. METHODS: Acetic acid smear test was performed on 1997 previously unscreened women aged 35-45 years in Xiangyuan County, Shanxi Province. All women had cervical cytology, testing for high-risk types of human papillomavirus DNA, colposcopy, an endocervical curettage and at least five cervical biopsies. Biopsies were done at the lesions, or one biopsy at 2, 4, 8, 10 o'clock at the squamocolumnar junction in each normal quadrant. RESULTS: According to histological diagnosis, 43 women had CIN II, 31 had CIN III, and 12 had invasive carcinoma. In two women only the endocervix was positive. Smear test yielded normal results in 1445 women (72.4%), low-grade squamous intraepithelial lesions (LSILs, CIN I) in 525 (26.3%), high-grade squamous intraepithelial lesions (HSILs, CIN II- III) in 21 (1.1%), and cancer in 6 (0.3%). With abnormal visual inspection defined as LSILs or worse, the sensitivity of acetic acid smear test for HSILs or worse was 70.9% (61 of 86), the specificity was 74.3% (1420 of 1911). The sensitivity was 64.9% for smaller lesions (37 of 57), and 88.9% for larger lesions (24 of 27) (P=0.03). The sensitivity of colposcopy for high-grade SILs or worse was 81.4% (70 of 86), the specificity was 76.5% (1462 of 1911). CONCLUSION: This study showed the high specificity and sensitivity of acetic acid smear test as a primary screening test for cervical cancer. Acetic acid smear test and colposcopy have similar specificity profiles for CIN II or more severe lesions. Acetic acid smear test as a primary screening test will be possible and effective with the benefits of low-cost and simple test in low-resource settings.

Acetic Acid↗
PubMed2003

[Clinical features and management of recurrence of severe acute respiratory syndrome].

OBJECTIVE: To investigate the clinical features of recurrence of severe acute respiratory syndrome (SARS) and therapeutic response. METHODS: Recurrence was analyzed retrospectively in SARS patients referred to our hospital from April to May this year to understand the clinical features, the recurrent related factors, the response of treatment and the outcomes. RESULTS: One hundred and twenty three patients with SARS were referred to the First Hospital of Peking University from 8, April to 14, May this year and of whom 51 were the critical. Twenty-five patients experienced recurrence, account for 20.3% of total patients (25/123) and 31.4% of critical patients. The clinical features included recurrent fever, worsened breathlessness, exacerbation in radiological lesions and elevated LDH, etc.. These patients were treated with glucocorticoids. Eleven of them were mechanical ventilated. Twenty-one patients recovered. Pulmonary fibrosis were left in 2 patients and another 2 patients died. CONCLUSION: The recurrence of symptoms in SARS patients is one of the common clinical feature of critical patients with SARS. Mechanism of recurrence in SARS patient is unknown. Management with glucocorticoids and noninvasive ventilation can control the progression in these patients effectively.

Disease Progression↗
PubMed2003

Smaller and faster: using a handheld computer to support a bedside vascular access team.

An application for a handheld computer was developed to support the Vascular Access team in an academic medical center. The development involved workflow analysis and usability testing centered on the users. The application interfaced with the desktop to generate the documentation needed for the charts and to populate the database used to track productivity, volume, outcomes, etc. Post-implementation evaluations provided feedback to validate the utility of the system to support workflow of the team.

Catheterization, Central Venous↗
PubMed2003

[Advances in studies on flavonoids of licorice].

The progress in the research of the active ingredients of licorice flavonoid and the pharmacological activities was reviewed. Licorice flavonoid constituents mainly included flavones, flavonals, isoflavones, chalcones, bihydroflavones and bihydrochalcones. Pharmacological investigation concluded that they had antioxidant, antibacterial, antitumer and inhibiting HIV activities. It is important to study further the flavonoid constituents and pharmacological activities.

Animals↗
PubMed2002

Expression, crystallization and preliminary X-ray analysis of isomaltulose synthase (PalI) from Klebsiella sp. LX3.

Isomaltulose synthase (PalI) catalyzes the hydrolysis of the alpha-1,2 bond between the glucose and fructose moieties of sucrose and the formation of alpha-1,6 and alpha-1,1 bonds between the two components to produce isomaltulose (alpha-D-glucosylpyranosyl-1,6-D-fructofranose) and trehalulose (alpha-D-glucosylpyranosyl-1,1-D-fructofranose), respectively. The PalI protein has been overexpressed, purified and crystallized at 295 K using the hanging-drop vapour-diffusion method. The crystals diffract to 2.2 A resolution using synchrotron radiation and belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 59.239, b = 94.153, c = 111.294 A.

Amino Acid Sequence↗
PubMed2002

Crystallization of an alpha-amylase, AmyA, from the thermophilic halophile Halothermothrix orenii.

This report is the first crystallographic study of an amylase from an organism that is both thermophilic and halophilic. alpha-Amylase from the thermophilic halophile Halothermothrix orenii (AmyA) is a 515-residue protein. It is stable and significantly active at 338 K in starch solution containing NaCl [up to 25%(w/v)]. Purified recombinant AmyA protein crystallizes in the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 55.126, b = 61.658, c = 147.625 A, using the hanging-drop vapour-diffusion method. The crystal diffracts X-rays to a resolution limit of 1.89 A.

Bacterial Proteins↗
PubMed2002

Quantitative polymerase chain reaction using capillary electrophoresis with laser-induced fluorescence detection: Analysis of duck hepatitis B.

We report an accurate and reproducible DNA quantitation method using the polymerase chain reaction (PCR). The amount of PCR product is monitored after each PCR cycle by capillary electrophoresis. To ensure accurate quantitation, a non-amplified internal standard is added to each PCR-amplified electrophoresis sample to correct for variations in injection volume. Quantitation of the sample is based on the number of cycles necessary to generate a predetermined amount of PCR product. Duck hepatitis B virus genome was used as a model in this study. The genome was quantified with a linear relationship between cycle number and logarithm of sample DNA for amounts of sample DNA between 30 and 3.1 x 10(8) copies ( r(2)>0.999). The relative standard deviation for the corrected capillary electrophoresis signal was 2.7%, while the relative standard deviation for the overall assay was 3.0%. Results from a single-blind study generated a relative error of 1.3%.

Animals↗
PubMed2002

Activation of antigen-presenting cells by immunostimulatory plant DNA: a natural resource for potential adjuvant.

Genomic DNA sequences (bacteria, insect, nematodes and molluscs) or synthetic oligodeoxynucleotides (ODN) containing unmethylated CpG motifs (CpG-DNA/ODN) are regarded as promising candidates for new medical adjuvants for their ability to stimulate the mammalian immune system and enhance immune responses to specific antigens. Here, we first report the immunostimulatory activity of total genomic DNA from two plants, Brassica chinensis L. and Zea may, the CpG methylation status of which is incomplete compared with E. coli DNA. These plant DNA can activate B cells to proliferate. Plant DNA promotes secretion of IL-12, and increases expression of MHC and costimulatory molecules by bone marrow-derived dendritic cells (BMDC). Plant DNA can also enhance antigen presentation capacity of BMDC and macrophages. When administrated in vivo, plant DNA can inhibit tumor growth in situ or metastasis in tumor-bearing mice. The immunostimulatory activity of plant DNA could be abolished by methylation. Our data showed that plant DNA can activate antigen-presenting cells (APC) including DC, macrophages and B cells, indicating that plant DNA is a new kind of potential adjuvant. Therefore, we conclude that plant DNA is another natural source of CpG-DNA, and that green plants may provide abundant resources for this potential medical adjuvant.

Adjuvants, Immunologic↗
PubMed2002

Use of a small reporter molecule to determine cell-surface proteins by capillary electrophoresis and laser-induced fluorescence: use of 5-SAENTA-x8f for quantitation of the human equilibrative nucleoside transporter 1 protein.

The human equilibrative nucleoside transporter 1 protein (hENT1) is a major mediator of cellular entry of nucleosides and anticancer nucleoside drugs; its assay is important in understanding and diagnosing chemotherapy resistance. Here we present a novel assay for quantifying hENT1 using capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). A cellular population is treated with 5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine-x8-fluorescein (5-SAENTA-x8f), which binds with high affinity and specificity to the hENT1 protein. The cells are washed to remove excess reagent, lysed, and centrifuged, and the supernatant is analyzed by CE-LIF with the use of an internal standard. Accuracy was evaluated by comparing the capillary electrophoresis results with those obtained by flow cytometry; the results were highly correlated, r = 0.96. The relative standard deviation of the hENT1 assay was 10%, determined from nine independent assays of the same cell line, which is 3 times superior to results obtained in a flow cytometry assay. The detection limit for 5-SAENTA-x8f was 4300 molecules injected into the capillary.

Adenosine↗
PubMed2002

Glutamine: clinical applications and mechanisms of action.

Supplementation of the conditionally essential amino acid glutamine may be beneficial for individuals who are highly stressed and have minimal energy and protein reserves. This includes elderly individuals, postoperative patients, individuals with cancer and very low birthweight infants. Individuals who are undergoing treatment with catabolic glucocorticoids may also benefit. Unfortunately, confusion exists as to situations in which glutamine may be beneficial because a clearly defined "glutamine deficiency syndrome" has not been described as for some other nutrients. In this review, we will discuss how glutamine affects protein metabolism under certain stressful conditions, how it affects intestinal mucosal integrity and how this might relate to sepsis and systemic inflammation. We will also discuss nutrients that are closely related to glutamine such as glutamate, nucleotides, arginine, glucosamines, and ornithine alpha-ketoglutarate and how and why they might be used as substitutes for glutamine.

Critical Illness↗
PubMed2002

D-AP5 blocks the increase of intracellular free Ca2+ induced by glutamate in isolated cochlear IHCs.

OBJECTIVE: To investigate the effect of D-AP5 (D-2-amino-5-phosphonopentanoate, a specific NMDA-antagonist) on the increase of intracellular free Ca2+ concentration ([Ca2+]i) induced by glutamate in isolated cochlear inner hair cells (IHCs), and to detect the autoreceptors of the IHC membrane. METHODS: When a laser scanning confocal microscope (LSCM) was used, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs and OHCs of guinea pig cochlea were observed with fluo-3, a fluorescent probe for [Ca2+]i. After D-AP5 or CNQX (6--cyano--7--nitroguinoxaline--2, 3--dione, a specific AMPA- antagonist) was administered, the exogenous glutamate (Glu)-induced changes in [Ca2+]i of isolated IHCs were recorded. RESULTS: In the presence of a low concentration Glu (3.85 mumol/L), there was an increase of [Ca2+]i in IHCs, whereas there was no change in OHCs. When 50 mumol/L of D-AP5 was administrated in advance, Glu did not induce a corresponding increase in [Ca2+]i in IHCs, and 50 mumol/L of CNQX did not completely block the increase of [Ca2+]i in IHCs. CONCLUSIONS: These results suggest that the autoreceptors existing in the IHC membrane are mainly of NMDA type, while there are relatively few AMPA receptors. Exogenous Glu is capable of increasing [Ca2+]i in IHCs by acting on the NMDA autoreceptor of IHCs in a positive feedback manner.

2-Amino-5-phosphonovalerate↗
PubMed2002

Augmentation of sodium butyrate-induced apoptosis by phosphatidylinositol 3'-kinase inhibition in the KM20 human colon cancer cell line.

PURPOSE: We have recently shown that inhibition of the phosphatidylinositol3'-kinase (PI3k) pathway enhances sodium butyrate (NaBT)-mediated differentiation of human colon cancer cells. The purpose of this study was to determine whether PI3k inhibition can enhance the inhibitory effect of NaBT on an aggressive human colon cancer cell line, KM20. EXPERIMENTAL DESIGN: The KM20 cell line, established from a metastatic colon cancer, was treated in vitro with NaBT, gemcitabine, or 5-fluorouracil either alone or in combination with the PI3k inhibitors wortmannin or LY294002; DNA fragmentation and cell viability were measured. As further indicators of apoptosis, protein was extracted to determine caspase-9 and caspase-3 activation and cleavage of poly(ADP-ribose) polymerase. In addition, the effect of NaBT and wortmannin on in vivo KM20 tumor growth was determined. RESULTS: We demonstrate that inhibition of PI3k enhanced NaBT-mediated apoptosis and decreased KM20 cell viability; the nonspecific caspase inhibitor zVAD-fmk blocked the induction of apoptosis by the combination treatment. Either wortmannin or LY294002, combined with NaBT, enhanced activation of caspase-9 and caspase-3 and the subsequent cleavage of poly(ADP-ribose) polymerase. Furthermore, inhibition of PI3k increased the sensitivity of KM20 cells to gemcitabine and 5-fluorouracil. Wortmannin alone inhibited KM20 xenograft growth in vivo; the combination of wortmannin and NaBT demonstrated an enhanced effect compared with either agent alone. CONCLUSIONS: Our results are the first to show that inhibition of PI3k enhances NaBT-mediated colon cancer cell apoptosis through the activation of caspase-9 and caspase-3. Moreover, these findings suggest that agents that selectively target the PI3k pathway may enhance the effects of standard chemotherapeutic agents and provide novel adjuvant treatment for selected colon cancers.

Animals↗
PubMed2002

Intervention by azithromycin on bleomycin-induced lung injury in rats and its mechanisms.

OBJECTIVE: To study the role of Th1/Th2 balance in the pathogenesis of pulmonary fibrosis and to investigate the therapeutic mechanisms of azithromycin. METHODS: Male wistar rats were randomly divided into three experimental groups: the bleomycin A(5) (BLM) group (BLM group), the azithromycin (AZI) group (AZI group) and the control group. Quantitative analysis of the histopathologic changes was performed by computer gray scan. The expression of IL-10 mRNA and IFN-gamma mRNA was examined by RNase protection assay (RPA). RESULTS: (1) In the BLM group, up-regulation of IL-10 mRNA was stronger than that of IFN-gamma mRNA, resulting in the inversion of the IL-10/IFN-gamma mRNA ratio, a shift from the Th1-like response of IFN-gamma predominance in the control group to the Th2-like response of IL-10 predominance in the BLM group. (2) The oral administration of AZI inhibited the expression of IL-10 and IFN-gamma mRNA; reversed the Th2-like response in the BLM group to the Th1-like response on day 7; and decreased the exudation of inflammatory cells as well as the degree of fibrosis. CONCLUSIONS: (1) At the early stage of fibrosing alveolitis, Th2 domination and the lack of IFN-gamma in the presence of alveolar epithelial and basement membrane injury may promote the development of fibrosis. (2) Azithromycin can inhibit the expression of IL-10 and IFN-gamma, and reverse the Th2-like response in the BLM group to a Th1-like response, and as a result, decrease the inflammatory injury as well as the degree of BLM-induced lung injury in rats.

Animals↗
PubMed2002

[Relationship between vaginal sialidase bacteria vaginosis and chorioammionitis].

OBJECTIVE: To study the relationship among vaginal sialidase, bacterial vaginosis (BV), chorioammionitis and subsequent adverse outcome of pregnancy. METHODS: Vaginal sialidase was measured by colorimetry in samples of vaginal discharges from 80 pregnant women with BV (study group) and 60 normal pregnant women at same gestation weeks (control group). Color turning blue means positive of sialidase activity, and no color changing means negative. The diagnosis of chorioammionitis was based on pathological examination. RESULTS: Ninety six dot three percent, 3.3% exhibited sialidase activities in study group and control group, respectively. There were significant differences between these two groups (P < 0.001). By measuring vaginal sialidase activity, the sensitivity, specificity, positive and negative predictive value in diagnosing BV were 96.3%, 96.7%, 97.5% and 95.1%, respectively. Chorioammionitis, premature rupture of membranes, premature delivery and puerperal infection in sialidase positive group were significantly higher than the negative group. Sensitivity, specialty of sialidase activity for chorioammionitis were 87.5%, 50.0%, respectively. CONCLUSION: Vaginal sialidase activity has strong relation with bacterial vaginosis. Measuring vaginal sialidase activity is a fast, easy, and useful method to diagnose bacterial vaginosis. It also has relation with chorioammionitis and subsequent adverse outcome of pregnancy.

Chorioamnionitis↗