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Biomedical subjects

Feng Li

Publications and source records attributed to Feng Li.

At least 145 records · Page 8Linked to original sources
PubMed2005

[Anti-tumor effects of mouse factor VII-Staphylococcus enterotoxin A (mfVII) chimeric protein in mice].

OBJECTIVE: Mouse factor VII (mfVII), ligand of tissue factor (TF) which is frequently over-expressed during neovascularization activated by tumor growth, was fused to staphylococcus enterotoxin A (SEA) that mediates greater intensity of T-cell activation against tumor cells. The anti-tumor effects of the mfVII-SEA chimeric protein were evaluated. METHODS: Fusion of SEA and mfVII cDNA was constructed using adenovirus vector and produced in 293 packaging cell lines. The 293 cells containing the adenovirus were administered subcutaneously to mice. Fluorescence studies at the injection site and the liver were performed 3 days later. Mouse prostatic tumor RM-1 cells and mouse sarcoma MCA 205 H12 cell lines were then used in mice to create lung metastasis and subcutaneous tumor to carry out efficacy evaluation, respectively. RESULTS: Adenovirus released from the injected 293 cells only infected the subcutaneous tissue at the injection site. The in vivo experiments in mice revealed that formation of lung metastasis was strongly inhibited by the mfVII-SEA (23 +/- 8) compared to the vacant vector control group (193 +/- 38) and PBS control group (211 +/- 42) (P < 0.01). The mfVII-SEA also strongly suppressed tumor growth at the subcutaneous injection site (342.6 +/- 107.1) mm(3) compared to that of vacant vector control (2244.3 +/- 350) mm(3) and SEA (1208.3 +/- 210) mm(3) by the 23rd day. CONCLUSION: The chimeric protein mfVII-SEA significantly inhibits lung metastasis formation and local tumor growth.

Animals↗
PubMed2005

[Cell differentiation during carcinogenesis of cervical epithelia].

BACKGROUND & OBJECTIVE: The disturbance of cell differentiation is an important characteristic of tumor, but, up to date, the researches on this aspect are not as deep as those on cell proliferation of tumor. This study was to detect the alterations of cell differentiation and relative regulating factors during the carcinogenesis of cervical epithelia. METHODS: The protein expression of keratin (KT) 10, 14, 19 and beta1-integrin and beta-catenin in 20 specimens of normal squamous epithelium (NSE), 19 specimens of dysplasia squamous epithelial hyperplasia (DSEH), 39 specimens of squamous carcinoma in situ (SCIS), and 20 specimens of invasive squamous epithelial carcinoma (ISEC) were detected by inmmunohistochemistry; the mRNA expression of of beta1-integrin and beta-catenin were detected by in situ hybridization. RESULTS: The strong positive rates of KT10 in NSE, DSEH, SCIS, and ISEC were 85.0%, 52.6%, 18.0% and 0, respectively, with a descending trend; it was significantly lower in SCIS and ISEC than in NSE and DSEH (Chi(2)=11.28, P<0.05; Chi(2)=8.53, P<0.05). The expression of KT14 and KT19 showed a heterogeneity in SCIS and ISEC: the proteins were negative in some cases, but overexpressed in other cases with positive cells moved upwards from the basal layer; positive cells scattered at the full epithelial layer of SCIS. The expression of beta1-integrin also showed a descending trend in NSE, DSEH, SCIS, and ISEC. The positive rate of beta1-integrin was significantly lower in ISEC than in NSE and DSEH (Chi(2)=7.62, P <0.05; value of exact probability=0.014, P < 0.05); the mRNA expression of beta1-integrin showed the same trend as its protein expression in the samples although the difference were not significant. The protein and mRNA expression of beta-catenin was located in nuclei or cytoplasm of SCIS and ISEC; increased positive cells moved upwards from the basal layer. CONCLUSIONS: Restraint of terminal differentiation of epithelial cells may relate to the abnormal expression of beta1-integrin and the dysfunction of Wnt signaling pathway on regulating cell differentiation during the carcinogenesis of cervical epithelia. The expression of KT10 and beta1-integrin in SCIS is not obviously different from that in ISEC.

Carcinoma in Situ↗
PubMed2005

[Anatermic separated epiphysis or avulsion fracture: image observation].

OBJECTIVE: To explore an approach to distinguish avulsion fracture of articular portion from anatomic separated epiphysis. METHODS: 21 cases with suspicioned avulsion fracture of articular portion of tubular bone were reviewed. The cortical continuity of separate small bone and contiguous bone portion was investigated. The swell of soft tissue around these small bones was observed simultaneously. Then the configuration of the fracture was researched by injury mechanics. RESULTS: Continued bone cortex between separate small bone and corresponding bone was seen in 15 cases, so they were considered as a separate epiphysis. Sharp linear fracture between the separate small bone and corresponding bone were seen in 6 cases. The swell of soft tissue around the separate small bone was observed in all cases, so they were considered as a avulsion fracture. CONCLUSION: The meticulous investigation of separated small bone at the articular portion by image observation is of important value for distinguishing avulsion fracture from anatomic separate epiphysis.

Adolescent↗
PubMed2005

[Application of syntactic pattern recognition in research on pulse wave's characteristic information].

In this paper, a syntactic pattern recognition method of the detection of pulse wave's characteristic information is introduced. According to it, the pressure signal of pulse is measured by non-invasive diagnostic method. Then, the elementary abstracting system transfers it into an input pattern. The recognizer, constructed by Earley algorithm, recognizes the pulse wave's pattern. On the base of it, the pulse wave's characteristic information can be got. Thus, the expert system will make a diagnosis with the information. The experiment result shows that, the new method is of anti-interference, preciseness and intelligence, and it provides an advanced, practical and intelligent means for the pulse diagnostic system.

Algorithms↗
PubMed2005

[A case-control study on risk factor of Kaposi's sarcoma in Xinjiang].

OBJECTIVE: To analyse related risk factors of classic Kaposi' s sarcoma in Xinjiang. METHODS: A 1:4 case-control study was used and the conditional logistic regression model was performed in this study. Cases were followed up in Xinjiang while controls were selected by the same sex, nation and age within 5 years with cases. RESULTS: Interleukin-6,vascular endothelial growth factor, beta-MG, neopterin, human herpevirus 8, were found to be associated with Kaposi's sarcoma risk in one-way variance model while beta2 -MG and human herpevirus 8 entered the multiple conditional logistic regression model, and their ORs were 1.002(95%CI: 1.000-1.003), 81.041 (95%CI: 1.790-3669.620). CONCLUSION: There was a correlate relationship between beta2 -MG and classic Kaposi's sarcoma being found that human herpevirus 8 exposure related factors seemed to have played important roles on classic Kaposi's sarcoma in Xinjiang.

Adult↗
PubMed2005

[Effects of ultrasound induction on genomic DNA of housefly larvae].

The genomic DNA of housefly larvae was extracted after ultrasound induction, and the structure was analyzed by UV, fluorescence, IR and 1H NMR. The 3'-end of attacin gene was sequenced and compared by means of PCR. All the results indicated that ultrasound induction can destroy the second structure and the base stacking of genomic DNA of housefly larvae, which will result in mismatch repair during DNA duplication and finally change the sequence of DNA, but it has no significant effect on chemical groups and chemical band of genomic DNA.

Animals↗
PubMed2004

GGA proteins mediate the recycling pathway of memapsin 2 (BACE).

Memapsin 2 (BACE, beta-secretase) is a membrane-associated aspartic protease that initiates the hydrolysis of beta-amyloid precursor protein (APP) leading to the production of amyloid-beta (A beta) and the progression of Alzheimer disease. Both memapsin 2 and APP are transported from the cell surface to endosomes where APP is cleaved by memapsin 2. We described previously that the cytosolic domain of memapsin 2 contains an acid cluster-dileucine motif (ACDL) that binds the VHS (Vps-27, Hrs, and STAM) domain of Golgi-localized gamma-ear-containing ARF-binding (GGA) proteins (He, X., Zhu, G., Koelsch, G., Rodgers, K. K., Zhang, X. C., and Tang, J. (2003) Biochemistry 42, 12174-12180). Here we report that GGA proteins colocalize in the trans-Golgi network and endosomes with memapsin 2 and a memapsin 2 chimera containing a cytosolic domain of a mannose-6-phosphate receptor. Depleting cellular GGA proteins with RNA interference or mutation of serine 498 to stop the phosphorylation of ACDL resulted in the accumulation of memapsin 2 in early endosomes. A similar change of memapsin 2 localization also was observed when a retromer subunit, VPS26, was depleted. These observations suggest that GGA proteins function with the phosphorylated ACDL in the memapsin 2-recycling pathway from endosomes to trans-Golgi on the way back to the cell surface.

ADP-Ribosylation Factors↗
PubMed2004

Ditopic hexaazamacrocycles containing pyridine: synthesis, protonation and complexation studies.

Structural studies of metal complexes of five ditopic hexaazamacrocycles containing two pyridine rings ([n]py2N4 n= 18, 20, 22, 24 and 26) have been carried out. The synthesis of macrocycles [22]- to [26]-py2N4 are also reported. The protonation constants of the last three compounds and the stability constants of their complexes with Ni2+, Cu2+, Zn2+, and Pb2+ were determined at 25 degrees C in 0.10 mol dm(-3) KNO3 in aqueous solution. Our results with [22]py2N4 show significant differences from those described previously, while [24]py2N4 has not been studied before and [26]py2N4 is a new compound. Mononuclear and dinuclear complexes of the divalent metal ions studied with [22]- to [26]-py2N4 were found in solution. The stability constants for the ML complexes of the three ligands follow the Irving-Williams order: NiL2+ < CuL2+ >> ZnL2+ > PbL2+, however for the dinuclear complexes the values for Pb2+ complexes are higher than the corresponding values for the Ni2+ and the Zn2+ complexes. The X-ray single crystal structures of the supramolecular aggregates [Cu2([20]py2N4)(H2O)4][Cu(H2O)6](SO4)3 x 3H2O and [Cu(2)([20]py(2)N4)(CH3CN)4][Ni([20]py2N4)]2(ClO4)8 x H2O, which are composed of homodinuclear [Cu2([20]py2N4])(H2O)4]4+ and [Cu2([20]py2N4])(CH3CN))4]4+, and mononuclear species, [Cu(H2O)6]2+ and [Ni([20]py2N4)]2+, respectively, assembled by an extensive network of hydrogen bonds, are also reported. In both homodinuclear complexes the copper centres are located at the end of the macrocycle and display distorted square pyramidal coordination environments with the basal plane defined by three consecutive nitrogen donors and one solvent molecule, water in and acetonitrile in . The macrocycle adopts a concertina-type conformation leading to the formation of macrocyclic cavities with the two copper centres separated by intramolecular distances of 5.526(1) and 5.508(7) A in 1a and 2a, respectively. The mononuclear complex [Ni([20]py2N4])]2+ displays a distorted octahedral co-ordination environment with the macrocycle wrapping the metal centre in a helical shape. EPR spectroscopy of the copper complexes indicated the presence of mono- and dinuclear species.

Journal Article↗
PubMed2004

Genetic structure of Hmong-Mien speaking populations in East Asia as revealed by mtDNA lineages.

Hmong-Mien (H-M) is a major language family in East Asia, and its speakers distribute primarily in southern China and Southeast Asia. To date, genetic studies on H-M speaking populations are virtually absent in the literature. In this report, we present the results of an analysis of genetic variations in the mitochondrial DNA (mtDNA) hypervariable segment 1 (HVS1) region and diagnostic variants in the coding regions in 537 individuals sampled from 17 H-M populations across East Asia. The analysis showed that the haplogroups that are predominant in southern East Asia, including B, R9, N9a, and M7, account for 63% (ranging from 45% to 90%) of mtDNAs in H-M populations. Furthermore, analysis of molecular variance (AMOVA), phylogenetic tree analysis, and principal component (PC) analysis demonstrate closer relatedness between H-M and other southern East Asians, suggesting a general southern origin of maternal lineages in the H-M populations. The estimated ages of the mtDNA lineages that are specific to H-M coincide with those based on archeological cultures that have been associated with H-M. Analysis of genetic distance and phylogenetic tree indicated some extent of difference between the Hmong and the Mien populations. Together with the higher frequency of north-dominating lineages observed in the Hmong people, our results indicate that the Hmong populations had experienced more contact with the northern East Asians, a finding consistent with historical evidence. Moreover, our data defined some new (sub-)haplogroups (A6, B4e, B4f, C5, F1a1, F1a1a, and R9c), which will direct further efforts to improve the phylogeny of East Asian mtDNAs.

Asia, Southeastern↗
PubMed2004

Malignant versus benign nodules at CT screening for lung cancer: comparison of thin-section CT findings.

PURPOSE: To evaluate thin-section computed tomographic (CT) characteristics of malignant nodules on the basis of overall appearance (pure ground-glass opacity [GGO], mixed GGO, or solid opacity) in comparison with the appearance of benign nodules. MATERIALS AND METHODS: Institutional review board approval and patient consent were obtained. Follow-up diagnostic CT was performed in 747 suspicious pulmonary nodules detected at low-dose CT screening (17 892 examinations). Of 747 nodules, 222 were evaluated at thin-section CT (1-mm collimation), which included 59 cancers and 163 benign nodules (3-20 mm). Thin-section CT findings of malignant versus benign nodules with pure GGO (17 vs 12 lesions), mixed GGO (27 vs 29 lesions), or solid opacity (15 vs 122 lesions) were analyzed. Fisher exact test for independence was used to compare differences in shape, margin, and internal features between benign and malignant nodules. Positive predictive value (PPV) was analyzed when a category was significantly different from the others. RESULTS: Among nodules with pure GGO, a round shape was found more frequently in malignant lesions (11 of 17, 65%) than in benign lesions (two of 12, 17%; P = .02; PPV, 85%); mixed GGO, a subtype with GGO in the periphery and a high-attenuation zone in the center, was seen much more often in malignant lesions (11 of 27, 41%) than in benign lesions (two of 29, 7%; P = .004; PPV, 85%). Among solid nodules, a polygonal shape or a smooth or somewhat smooth margin was present less frequently in malignant than in benign lesions (polygonal shape: 7% vs 38%, P = .02; smooth or somewhat smooth margin: 0% vs 63%, P < .001), and 98% (46 of 47) of polygonal nodules and 100% (77 of 77) of nodules with a smooth or somewhat smooth margin were benign. CONCLUSION: Recognition of certain characteristics at thin-section CT can be helpful in differentiating small malignant nodules from benign nodules.

Adenocarcinoma↗
PubMed2004

[Diagnostic significance and clinical application of specific chimeric genes in soft tissue sarcomas by RT-PCR using paraffin-embedded tissues: a study of 103 specimens].

OBJECTIVE: To investigate the expression of the chimeric genes resulting from the specific chromosomal translocations in soft tissue sarcomas (STS) and its diagnostic significance for STS. METHODS: The variety of fusion transcripts were detected in 103 cases of STS, including 30 cases of synovial sarcoma (SS), 15 cases of rhabdomyosarcoma (RMS), 25 cases of Ewing's sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET), 12 cases of dermatofibrosarcoma protuberans (DFSP), 14 cases of aveolar soft part sarcoma (ASPS), 3 cases of leiomyosarcoma (LMS), 2 cases of malignant fibrous histocytoma (MFH), and 2 cases of fibrosarcoma (FS); and 20 cases of control tumors by reverse transcription-polymerase chain reaction (RT-PCR) using formalin fixed, paraffin embedded specimens. RESULTS: Of the 34 cases of SS 28 (93.3%) expressed SSX-SYT chimeric transcripts (14 were positive for SYT-SSX1, 9 for SYT-SSX2). Four of the six cases of alveolar RMS had a PAX3/PAX7-FKHR fusion transcript. None of the 9 cases of embryonic and polymorphic RMS expressed PAX3/PAX7-FKHR. Of the 25 cases of ES/pPNET, 19 were positive for EWS-FLI1 fusion transcript and 1 for EWS-ERG fusion transcript. COL1A1-PDGFB fusion transcript was expressed in 8 of the 12 cases (66.7%) of DFSP. Of the fourteen cases of ASPS, ten expressed ASPL-TFE3 fusion transcript. None of the 3 cases of LMS, 2 cases of MFH, 2 cases of FS, and 20 control cases contained any of the fusion transcript. CONCLUSION: Chimeric gene transcript resulting from specific chromosomal translocations is a reliable index for the molecular diagnosis of STS and RT-PCR assay for detection of specific fusion gene provides a useful tool for confirmation of the diagnosis of STS in diagnostically difficult cases and in retrospective studies.

Artificial Gene Fusion↗
PubMed2004

Genetic evidence supports demic diffusion of Han culture.

The spread of culture and language in human populations is explained by two alternative models: the demic diffusion model, which involves mass movement of people; and the cultural diffusion model, which refers to cultural impact between populations and involves limited genetic exchange between them. The mechanism of the peopling of Europe has long been debated, a key issue being whether the diffusion of agriculture and language from the Near East was concomitant with a large movement of farmers. Here we show, by systematically analysing Y-chromosome and mitochondrial DNA variation in Han populations, that the pattern of the southward expansion of Han culture is consistent with the demic diffusion model, and that males played a larger role than females in this expansion. The Han people, who all share the same culture and language, exceed 1.16 billion (2000 census), and are by far the largest ethnic group in the world. The expansion process of Han culture is thus of great interest to researchers in many fields.

Agriculture↗
PubMed2004

Cross sections of electron inelastic interactions in DNA.

The cross sections of electron inelastic interaction in DNA are calculated using the dielectric response theory and Penn statistical approximation, with the exchange correction included. An empirical approach to obtain optical energy loss function is given for the organic compounds without available optical data. Comparisons of the calculated data with available experimental and theoretical results have been done to show the reliability of the approach proposed in this work. Using this approach, the total inelastic cross sections for five bases: guanine, adenine, thymine, cytosine and uracil have been calculated in the energy range of E< or =10 keV and compared with those recently obtained with the Deutsch-Mark formalism and the Binary-Encounter-Bethe model, respectively. An equivalent unit of the DNA molecule is constructed according to the contents of A-T and G-C base pairs in DNA, and is divided into five constituents, i.e. sugar-phosphate and four bases. The total inelastic cross sections for the constructed unit of the DNA molecule and its constituents have also been calculated.

Binding Sites↗
PubMed2004

RNA silencing: a conserved antiviral immunity of plants and animals.

RNA silencing is a novel RNA-guided gene regulatory mechanism operational in a wide range of eukaryotic organisms from fission yeast, plants, to mammals. This article reviews the recent progress on aspects of RNA silencing that are related to its biological function as a conserved antiviral immunity of plants and animals, and highlights features of this novel antiviral response in invertebrate animals as compared to the known innate and adaptive immunities. Finally, we discuss evidence that suggests a natural antiviral role for RNA silencing in vertebrates as well as experimental approaches that may facilitate the identification of first mammalian viral suppressors of RNA silencing.

Animals↗
PubMed2004

Protection against ischemic brain damage in rats by immunophilin ligand GPI-1046.

To determine the effect of immunophilin ligand GPI-1046 on ischemic brain injury, 90 min of transient middle cerebral artery occlusion (MCAO) was carried out in rat brains. In contrast to cases treated with vehicle, the infarct volume was reduced greatly and rotamase activity was inhibited significantly at 24 hr of reperfusion by treatment with GPI-1046. Immunoreactivity and the number of cells stained positively for FKBP12, FKBP52, caspase-8, cytochrome c, and caspase-3 were also reduced markedly in the brain after GPI-1046 treatment. The present results suggest that GPI-1046 significantly decreased infarct volume and provided neuroprotective effect on rats after transient focal cerebral ischemia by inhibiting the increase of rotamase activity and of the number of FKBP12-, FKBP52-, caspase-8-, cytochrome c-, and caspase-3-positive cells in the ischemic area.

Analysis of Variance↗
PubMed2004

Involvement of phosphatidylinositol 3-kinase and insulin-like growth factor-I in YXLST-mediated neuroprotection.

In the present study, we examine the neuroprotective role of the external Qi of YXLST in cultured retinal neurons. Primary retinal neuronal cultures were grown from retinas of 0-2-day-old Sprague-Dawley rats. Cultures were treated directly with external Qi of YXLST 30 min prior to H(2)O(2) exposure in most experiments. Cell viability was measured by 3,(4,5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) assay. Apoptotic cell death was evaluated by the TdT-mediated digoxigenin-dUTP nick-end labeling TUNEL assay, and by DNA laddering analysis. Northern blot analysis was performed to examine the level of insulin-like growth factor-I (IGF-I) gene expression. Phosphatidylinositol 3-kinase (PI3K) assay was performed to study the PI3K activity. The results showed that treatment of external Qi of YXLST significantly attenuated neuronal death that was induced by 24-h exposure to hydrogen peroxide, and greatly inhibited hydrogen peroxide-induced apoptosis. External Qi of YXLST also upregulated IGF-I gene expression and increased PI3K activity. These observations indicate that external Qi-mediated IGF-I expression and PI3K signaling could be one of the mechanisms in neuroprotection by YXLST.

Animals↗