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Xin Li

Publications and source records attributed to Xin Li.

At least 163 records · Page 9Linked to original sources
PubMed2005

Evidence for shutter-speed variation in CR bolus-tracking studies of human pathology.

The standard pharmacokinetic model for the analysis of MRI contrast reagent (CR) bolus-tracking (B-T) data assumes that the mean intracellular water molecule lifetime (tau(i)) is effectively zero. This assertion is inconsistent with a considerable body of physiological measurements. Furthermore, theory and simulation show the B-T time-course shape to be very sensitive to the tau(i) magnitude in the physiological range (hundreds of milliseconds to several seconds). Consequently, this standard model aspect can cause significant underestimations (factors of 2 or 3) of the two parameters usually determined: K(trans), the vascular wall CR transfer rate constant, and v(e), the CR distribution volume (the extracellular, extravascular space fraction). Analyses of animal model data confirmed two predicted behaviors indicative of this standard model inadequacy: (1) a specific temporal pattern for the mismatch between the best-fitted curve and data; and (2) an inverse dependence of the curve's K(trans) and v(e) magnitudes on the CR dose. These parameters should be CR dose-independent. The most parsimonious analysis allowing for realistic tau(i) values is the 'shutter-speed' model. Its application to the experimental animal data essentially eliminated the two standard model signature inadequacies. This paper reports the first survey for the extent of this 'shutter-speed effect' in human data. Retrospective analyses are made of clinical data chosen from a range of pathology (the active multiple sclerosis lesion, the invasive ductal carcinoma breast tumor, and osteosarcoma in the leg) that provides a wide variation, particularly of K(trans). The signature temporal mismatch of the standard model is observed in all cases, and is essentially eliminated by use of the shutter-speed model. Pixel-by-pixel maps show that parameter values from the shutter-speed analysis are increased by more than a factor of 3 for some lesion regions. This endows the lesions with very high contrast, and reveals heterogeneities that are often not seen in the standard model maps. Normal muscle regions in the leg allow validation of the shutter-speed model K(trans), v(e), and tau(i) magnitudes, by comparison with results of previous careful rat leg studies not possible for human subjects.

Adult↗
PubMed2005

Liquid chromatography/tandem mass spectrometry for pharmacokinetic studies of 20(R)-ginsenoside Rg3 in dog.

A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the investigation of the pharmacokinetics of 20(R)-ginsenoside Rg3 in dog. The plasma samples were pretreated by liquid-liquid extraction and analyzed using LC/MS/MS with an electrospray ionization interface. Dioscin was used as the internal standard. The method had a lower limit of quantitation of 0.5 ng/mL for Rg3 in 200 microL of plasma or 2 ng/mL in 100 microL of plasma, which offered a satisfactory sensitivity for the determination of Rg3 in plasma. The intra- and inter-day precisions were measured to be below 8% and accuracy between -1.5 and 1.4% for all quality control samples. This quantitation method was successfully applied to pharmacokinetic studies of Rg3 after both an oral and an intravenous administration to beagle dogs. No Rh2 and protopanaxadiol were detected in plasma.

Administration, Oral↗
PubMed2005

Molecular cloning and characterization of a novel human C4orf13 gene, tentatively a member of the sodium bile acid cotransporter family.

By large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a novel human cDNA (C4orf13). This cDNA is 2706 bp in length, encoding a 340-amino-acid polypeptide that contains a typical SBF (sodium bile acid cotransporter family) domain and ten possible transmembrane segments. The putative protein C4orf13 shows high similarity with its orthologs in Mus musculus and Xenopus laevis. Human C4orf13 is mapped to chromosome 4q31.2 and contains 12 exons. RT-PCR analysis shows that human C4orf13 is widely expressed in human tissues, and the expression levels in liver and lung are relatively high, expression levels in placenta, kidney, spleen, and thymus are moderate, low levels of expression are detected in heart, prostate, and testis.

Amino Acid Sequence↗
PubMed2005

Cloning and characterization of a novel human phosphatidic acid phosphatase type 2, PAP2d, with two different transcripts PAP2d_v1 and PAP2d_v2.

This study reports the cloning and characterization of a novel human phosphatidic acid phosphatase type 2 isoform cDNAs (PAP2d) from the foetal brain cDNA library. The PAP2d gene is localized on chromosome 1p21.3. It contains six exons and spans 112 kb of the genomic DNA. By large-scale cDNA sequencing we found two splice variants of PAP2d, PAP2d_v1 and PAP2d_v2. The PAP2d_v1 cDNA is 1722 bp in length and spans an open reading frame from nucleotide 56 to 1021, encoding a 321aa protein. The PAP2d_v2 cDNA is 1707 bp in length encoding a 316aa protein from nucleotide 56-1006. The PAP2d_v1 cDNA is 15 bp longer than the PAP2d_v2 cDNA in the terminal of the fifth exon and it creates different ORF. Both of the proteins contain a well-conserved PAP2 motif. The PAP2d_v1 is mainly expressed in human brain, lung, kidney, testis and colon, while PAP2d_v2 is restricted to human placenta, skeletal muscle, and kidney. The two splice variants are co-expressed only in kidney.

Alternative Splicing↗
PubMed2005

Molecular cloning and characterization of AAAS-V2, a novel splice variant of human AAAS.

Triple-A syndrome (MIM 231550; also known as Allgrove syndrome) is an autosomal recessive disorder characterized by adrenocorticotropin hormone (ACTH)-resistant adrenal insufficiency, achalasia of the oesophageal cardia and alacrima. Much initial molecular analysis supported that Triple-A syndrome was caused by mutations in AAAS, a WD-repeat protein gene. Here we report cloning and characterization of a novel splice variant of human AAAS, which we named AAAS-v2, which is located on the human chromosome 12p13. The cDNA is 1703 bp, encoding a 513-amino acid polypeptide, which contains three WD40 domains, one less than the original which we called AAAS-v1 (Gen Bank: NM_015665.3). RT-PCR analysis in our work revealed that AAAS-v2 and AAAS-v1 were ubiquitously detected in human multiple tissue cDNA (MTC) panels (CLONTECH).

Alternative Splicing↗
PubMed2005

A method for filling in the cohesive ends of double-stranded DNA using Pfu DNA polymerase.

The present paper reports a highly efficient method of making blunt ends from cohesive ends of double-stranded DNA. Klenow fragment and Pfu DNA polymerases were used to fill in the cohesive ends. Since the transformation efficiency can directly reflect the filling-in efficiency, similar ligation and transformation conditions were used, and the filling-in efficiency was compared with the corresponding transformation efficiency. The results indicate that the filling-in efficiency of Pfu DNA polymerase was 1.96 times that of Klenow fragment and its efficiency was markedly higher than that of Klenow fragment (P<0.01). The optimization experiments on reaction conditions indicate, when the pH is 8.5 and the temperature is 74 degrees C, that the filling-in efficiency was highest upon using a buffer containing 3 mM MgSO4 and 300 microM dNTP.

Buffers↗
PubMed2005

New sesquiterpenes from Erigeron annus.

Four new and five known eudesmane-type sesquiterpenes were isolated from the aerial parts of Erigeron annus. The structures of these new compounds were elucidated by spectral means, including 2D-NMR analysis, to be 1 beta,4 beta-dihydroxyeudesman-11-ene; 1 beta,7 alpha-dihydroxyeudesman-4(15)-ene; (1 R,5 S,6 S,7 S,10 R)-1 beta, 6 alpha-dihydroxyeudesman-4-one and 1 beta- D-glucopyranosyloxy-6 alpha-hydroxyeudesman-4(15)-ene. In addition, a chemical transformation of a known compound 1 beta,6 alpha-dihydroxy-eudesman-4 (15)-ene was carried out and the derivative 1beta,6alpha-dihydroxy-4beta(15)-epoxyeudesmane was obtained. Some of the compounds were evaluated for their in vitro antitumor activities.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Demosaicing by successive approximation.

In this paper, we present a fast and high-performance algorithm for color filter array (CFA) demosaicing. CFA demosaicing is formulated as a problem of reconstructing correlated signals from their downsampled versions with an opposite phase. The major contributions of this work include (1) a new iterative demosaicing algorithm in the color difference domain and (2) a spatially adaptive stopping criterion for suppressing color misregistration and zipper artifacts in the demosaiced images. We have compared the proposed demosaicing algorithm with two current state-of-the-art techniques reported in the literature. Ours outperforms both of them on demosaicing performance and computational cost.

Algorithms↗
PubMed2005

Reexploring the possible roles of some genes associated with nasopharyngeal carcinoma using microarray-based detection.

In gene expression profiling, nasopharyngeal carcinoma (NPC) 5-8F cells differ from 6-10B cells in terms of their high tumorigenicity and metastatic ability. Differentially expressed genes from the two cell types were analyzed by combining with MILANO (the automatic custom annotation of microarray results which is based on all the available published work in PubMed). The results showed that five genes, including CTSD, P63, CSE1L, BPAG1 and EGR1, have been studied or mentioned in published work on NPC. Subsequently, we reevaluated the roles of these genes in the pathogenesis of NPC by combining the data of gene chips from NPCs versus NPs and pooled cells from 5-8F, 6-10B and CNE2 versus NPs. The results suggested that the roles of BPAG1 and EGR1 are possibly different from those reported in previous NPC studies. These five genes are likely to be involved in the proliferation, apoptosis, invasion and metastasis of NPC. A reexploration of the genes will further define their roles in the pathogenesis of NPC.

Biomarkers, Tumor↗
PubMed2005

Association of linear plasmid 28-1 with an arthritic phenotype of Borrelia burgdorferi.

Borrelia burgdorferi, the Lyme disease spirochete, has a genome comprised of a linear chromosome and up to 21 plasmids. Loss of plasmids is associated with decreased infectivity and pathogenicity. Sixteen transformants were generated by transforming the noninfectious clone 5A13 with the recombinant plasmid pBBE22. The transformants were classified into nine groups based on plasmid content analysis. An infectivity study revealed that all nine transformants examined, each of which represented one of the plasmid patterns, were infectious in mice with severe combined immunodeficiency (SCID) regardless of their genomic compositions. Tissue bacterial quantification revealed that the loss of plasmids significantly reduced the spirochete burden in the heart and joint tissues, not in the skin, suggesting virulence factors may be tissue specific. Four transformants containing lp28-1 induced severe arthritis in SCID mice, in contrast to the five transformants lacking lp28-1. These pathogenicity studies associated lp28-1 with an arthritic phenotype and further studies may identify factors that contribute to arthritic pathology.

Animals↗
PubMed2005

Correlation between hypoechoic nodules on ultrasonography and benign hyperplasia in the prostatic outer gland.

OBJECTIVE: The purpose of this investigation was to study the correlation between hypoechoic nodules detected on ultrasonography and benign hyperplasia in the prostatic outer gland (POG) diagnosed by transrectal ultrasonography (TRUS)-guided biopsies. METHODS: The TRUS-guided biopsies were performed on 472 patients suspected of having prostate cancer. Specimens obtained by biopsies were independently assessed by pathologists at 3 hospitals. RESULTS: The histologic results of 310 patients (65.68%) were benign. Focal hypoechoic nodules located in the POG were found in 240 patients (50.8%) on TRUS scans. Among them, in 22 patients (9.17% of the 240 patients with hypoechoic nodules), benign hyperplasia was found in focal hypoechoic nodules located in the POG. Focal nodules were seen as well circumscribed with an ovoid shape and smooth surface in 18 patients. CONCLUSIONS: Benign hyperplasia may sometimes originate in the POG and may appear as a hypoechoic nodule, similar to the appearance of prostate cancer.

Adult↗
PubMed2005

[Analysis of protein expression maps of two metastatic colorectal carcinoma cell lines generated by two-dimensional gel electrophoresis].

OBJECTIVE: To analyze the differentially expressed proteins in metastatic colorectal carcinoma and provide clues for the molecular mechanisms of colorectal cancer metastasis. METHODS: A pair of colorectal carcinoma cell lines SW620 and SW480 with different metastatic potentials from the same parent cell lines were studied. The protein expression maps of the two cell lines were obtained and optimized using two-dimensional gel electrophoresis (2-DE), and the differentially expressed protein spots associated with metastasis were analyzed by Melanie III software. RESULTS: The 2-DE expression maps of the two cell lines were well matched. The resolution of 2-DE was increased after using the nonlinear pH3-10 or overlapping narrow immobilized pH gradient strips, and 11 differentially expressed protein spots were identified after analysis using the software. CONCLUSION: Nonlinear pH3-10 and overlapping narrow immobilized pH gradient strips have higher separation efficiency for protein in 2-DE. The differentially expressed proteins separated will be useful for identifying metastasis-associated proteins of colorectal carcinoma and for establishing 2-DE database of the metastatic colorectal carcinoma cell lines.

Cell Line, Tumor↗
PubMed2005

[Effect of benzene on sperm DNA].

OBJECTIVE: To assess the effect of benzene on sperm DNA. METHODS: Twenty-seven workers exposed to benzene for over two years were included in the experiment group and 35 unexposed ones were chosen as controls. Damage by benzene on sperm DNA was detected by modified single cell gel electrophoresis (SCGE). RESULTS: The benzene concentration in the air of the workplace of the exposed workers was (86.49 +/- 2.83) mg/m3, twice that of the national maximum allowance (40 mg/cm3). Urinary, trans-muconic acid in the exposed group was (1.40 +/- 0.62) mg/L (n = 27), significantly higher than that of the controls [(0.82) +/- 0.16) mg/L, n = 35]. After SCGE, the percentage of head DNA in the exposed group [(70.18% +/- 7.36%, n = 13 ] was significantly lower than that of the controls (90.62% +/- 2.94%, n = 16), P < 0.001. CONCLUSION: Higher concentration of benzene could cause damage to the sperm DNA of the workers exposed to it.

Adult↗
PubMed2005

[ABO-incompatible nonmyeloablative allogeneic peripheral blood stem cell transplantation].

To explore the effects of ABO incompatibility between recipient and donor on HLA-matched nonmyeloablative allogeneic peripheral blood stem cell transplantation (NAST), a retrospective, cohort study was performed. Among 24 HLA-matched NAST, 15 were major ABO-incompatible and 9 minor. Control group included 24 HLA-matched NAST with ABO-compatible grafts. Nonmyeloablative conditioning regimens consisted of CTX, Ara-C and ATG. The patients were given cyclosporine A and mycophenolate mofetile for prophylaxis of acute GVHD. The ABO-incompatible patients received grafts depleted erythrocytes by hydroxyethyl starch (HES) sedimentation. The results showed that successful and stable engraftment was established in 23 patients. No recipient developed clinically immediate hemolysis during graft infusion, but 2 recipients experienced delayed hemolysis attributable to the ABO incompatibility. The median time of granulocyte counts >0.5 x 10(9)/L and platelet >30 x 10(9)/L was 11 and 14.9 days, respectively. In ABO major incompatible group, the onset of erythropoiesis after NAST was delayed. One out of 10 recipients with blood group "O" in this group developed pure red cell aplasia (PRCA), lasting 5 months. The acute GVHD occurred in 7 out of the 24 patients. The chronic GVHD occurred in 5 of 21 cases. Relapse was observed in 2 patients with acute leukemia. The actuarial probability of disease-free survival at 2 years was 63.3%. In conclusion, ABO-incompatible grafts for NAST have no adverse effect on engraftment, recovery of platelets, incidence of GVHD, relapse rate or survival. ABO-incompatible NAST is fairly safe if there is indication, however, the onset of erythropoiesis is delayed when major ABO mismatched.

ABO Blood-Group System↗
PubMed2005

[Quantitative morphometry of hyperplastic hypoechoic nodules in the prostatic outer gland].

OBJECTIVE: To explore the morphotic characteristics of hypoechoic nodules in the outer gland of the prostate with benign METHODS: Twenty-two hyperplastic hypoechoic nodules in the prostatic outer gland were biopsied guided by prostatic hyperplasia. transrectal ultrasound. The hematoxylin-eosin (HE) staining and immunohistochemistry combined with computer assisted quantitative image analyses were adopted to examine the mean percentages of the area densities of stroma, epithelium, glandular lumen and smooth muscle cells. RESULTS: The area densities of stroma, epithelium, glandular lumen and smooth muscle cells were (72.52 +/- 13.14)%, (20.57 +/- 9.01)%, (6.85 +/- 4.51)% and (24.14 +/- 6.31)%, respectively. CONCLUSION: Hyperplastic hypoechoic nodules may develop in the outer gland as well as in the inner gland of the prostate, but the mean percentages of the components are different between the two kinds of nodules.

Adult↗
PubMed2005

[Effects of Bacillus Calmette-Guerin vaccination on immune functional development of splenic T cell in neonatal mice].

OBJECTIVE: Almost every neonate receives Bacillus Calmette-Guerin (BCG) vaccination in China. The authors' previous study showed that BCG promoted cord blood monocyte-derived dendritic cells maturation and induced high level of interleukin (IL)-10, medium level of interferon (IFN)-gamma, but low level of IL-4 production by cord naive T cells. The experiments in the present study were designed to explore the effects of neonatal BCG vaccination on immune functional development of splenic T cells in mice in vivo. METHODS: Neonatal BALB/c mice were inoculated with BCG intraperiotoneally. Four weeks later, spleen cells of mice were isolated and surface molecular markers of CD4, CD25 and CD44 and intracellular IFN-gamma, IL-10, and IL-4 in CD3(+) T cells were detected by flow cytometry. Furthermore, mRNA expression of transcription factor T-bet, Foxp3 and GATA-3 were analyzed by RT-PCR. RESULTS: The percentage of total CD4(+) T cells decreased [(23.50 +/- 2.59)% vs. (47.38 +/- 10.41)%, P < 0.01] but the percentage of CD25(+) [(24.92 +/- 2.74)% vs. (20.27 +/- 2.85)%, P < 0.05] and CD44(+) [(89.29 +/- 2.56)% vs. (82.98 +/- 5.51)%, P < 0.05] T cells in CD4(+) T cells was higher in BCG-vaccinated mice than that in controls. Meanwhile, the percentage of IFN-gamma positive [(6.52 +/- 2.40)% vs. (3.13 +/- 2.03)%, P < 0.05] and IL-10 positive [(14.81 +/- 3.65)% vs. (10.90 +/- 1.61)%, P < 0.05] but not IL-4 positive [(1.17 +/- 0.46)% vs (1.51 +/- 0.75)%, P > 0.05] cells in CD3(+) T cells of BCG-vaccinated mice was significantly higher than that of non-BCG-vaccinated mice. In comparison with BCG-naive mice, T-bet was significantly high in BCG-vaccinated mice [T-bet/beta-actin 0.44 +/- 0.11 vs. 0.28 +/- 0.06, P < 0.05], but there was no significant difference in GATA-3 [GATA-3/beta-actin 0.46 +/- 0.08 vs. 0.50 +/- 0.10,P > 0.05] and Foxp3 [Foxp3/beta-actin vs. 0.27 +/- 0.11 and 0.30 +/- 0.16, P > 0.05] mRNA expression between the two groups. CONCLUSION: Neonatal BCG vaccination could induce strong Th1 but weak Th2 response as reported previously. Though neonatal BCG vaccination was not capable of inducing CD4(+)CD25(+) regulatory T cell response with Foxp3 expression, it caused increase of IL-10(+) CD3(+) cells which might represent some regulatory T cells producing IL-10.

Animals↗
PubMed2005

[The effect of high dose fluoride on the rat offspring osteoblasts which ingested by female rats].

OBJECTIVE: To investigate the effect of high dose fluoride which ingested by female rats on morphologic change in rat offspring's bone and osteoblast, discuss the relation between the mechanism of fluorosis and cell cycle, cell apoptosis. METHODS: In stock diets condition, Wistar female rats drank distilled water containing 0,50,100,150 mg/L NaF for 2 months, then they are mated with normal rats. The calvarium and osteoblast of offsprings were used to investigate the effects of fluoride on ultrastructure by LM and TEM. FCM was used to analysis cell cycle and apoptosis. RESULTS: The Electron microscope revealed the number of microvilli of osteoblasts were overall decreased in rat offsprings with fluorosis. There was mitochondrial swelling and dilation of the rough endoplasmic reticulum (RER). The matrix of calvarium was hyperplasia and collagen was accumulated and turbulenced. The nuclear manifested the apoptosis character. NaF at 150 mg/ L increased the osteoblast number of S phase with relative decrease of cell number of G2/M phase, but did not change that in G0/G1 phase. The apoptosis percentage increased in this group. CONCLUSION: Excessive fluoride can directly through the placental barrier, influence cell structure and cell cycle distribution of fluorosis rat offspring and render the cell cycle stagnant in S phase, induce apoptosis.

Animals↗