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Ping Liang

Publications and source records attributed to Ping Liang.

At least 55 records · Page 3Linked to original sources
PubMed2004

Contribution of postprandial lipemia to the dietary fat-mediated changes in endogenous lipoprotein-cholesterol concentrations in humans.

BACKGROUND: Dietary fats alter LDL and HDL cholesterol while serving as precursors of postprandial triacylglycerol-rich lipoproteins (TRLs). OBJECTIVE: We hypothesized that the saturated fatty acid (SFA)-mediated increase and the polyunsaturated fatty acid (PUFA)-mediated decrease in endogenous lipoprotein cholesterol are promoted by postprandial TRLs. DESIGN: We performed a 16-d crossover diet study to examine the effect of PUFA-rich [ratio of PUFAs to SFAs (P:S) = 2.0] and SFA-rich (P:S = 0.25) diets on fasting and postprandial plasma lipid and lipoprotein-cholesterol concentrations in 16 normolipidemic subjects. RESULTS: Fasting plasma cholesterol decreased significantly after a PUFA-rich diet because of a decrease in LDL (-12.3%; P < 0.05) and HDL (-3.8%; NS), but did not change after an SFA-rich diet. The appearance of postprandial TRLs in plasma at 4 h was linked to a significant lowering of both LDL (-7.4%) and HDL (-4.8%) after a PUFA-rich diet; no such effect was observed after the SFA-rich diet. At 7 h, LDL and HDL cholesterol returned to near fasting concentrations without postprandial TRL accumulation after a PUFA-rich diet but with a significant postprandial TRL accumulation after an SFA-rich diet. Thus, the in vivo postprandial clearance of cholesterol in LDL+HDL was greater after a PUFA-rich diet than after an SFA-rich diet. The appearance of postprandial TRLs in plasma increased the cholesteryl ester transfer protein-mediated transfer of cholesteryl ester from LDL+HDL to TRLs in vitro without a significant influence from dietary fat. CONCLUSION: Dietary fat-mediated alterations in the rate of hepatic removal of postprandial TRLs, which carry cholesterol accepted from LDL+HDL via cholesteryl ester transfer protein in vivo, may contribute to the dietary fat-mediated change in endogenous lipoprotein cholesterol.

Adult↗
PubMed2004

Microarray analysis for identification of Plasmodium-refractoriness candidate genes in mosquitoes.

The identification and cloning of genes conferring mosquito refractoriness to the malaria parasite is critical for understanding malaria transmission mechanisms and holds great promise for developing novel approaches to malaria control. The mosquito midgut is the first major site of interaction between the parasite and the mosquito. Failure of the parasite to negotiate this environment can be a barrier for development and is likely the main cause of mosquito refractoriness. This paper reports a study on Aedes aegypti midgut expressed sequence tag (EST) identification and the determination of genes differentially expressed in mosquito populations susceptible and refractory to the avian malaria parasite Plasmodium gallinaceum. We sequenced a total of 1200 cDNA clones and obtained 1183 high-quality mosquito midgut ESTs that were computationally collapsed into 105 contigs and 251 singlets. All 1200 midgut cDNA clones, together with an additional 102 genetically or physically mapped Ae. aegypti clones, were spotted on single arrays with 12 replicates. Of those interrogated microarray elements, 28 (2.3%) were differentially expressed between the susceptible and refractory mosquito populations. Twenty-seven elements showed at least a two-fold increase in expression in the susceptible population level relative to the refractory population and one clone showed reduced expression. Sequence analysis of these differentially expressed genes revealed that 10 showed no significant similarity to any known genes, 6 clones had matches with unannotated genes of Anopheles gambiae, and 12 clones exhibited significant similarity to known genes. Real-time quantitative RT-PCR of selected clones confirmed the mRNA expression profiles from the microarray analysis.

Aedes↗
PubMed2004

Prostate derived Ets transcription factor shows better tumor-association than other cancer-associated molecules.

We previously reported that prostate derived Ets transcription factor (PDEF) is a breast tumor-associated molecule. To obtain further insights into PDEF expression in other human tumor types, a cDNA library database from human adult normal and tumor tissues was compiled and searched for PDEF distribution. The results showed that PDEF is present at relative higher frequencies in the cDNA libraries from brain, breast, lung and ovarian tumors in comparison to those from the corresponding normal tissues. RT/PCR analysis of PDEF expression in ovarian tumors confirmed that PDEF is expressed in 36 out of 51 (71%) ovarian tumors. Further comparison of the distribution of PDEF with other widely recognized cancer-associated molecules showed that PDEF has more restricted distributions than Her-2/neu, Bcl-2, survivin or telomerase in cDNA libraries from normal human tissues and more increased distribution than Her-2/neu, CA-125, Bcl-2, survivin and telomerase in cDNA libraries from brain (except survivin), breast, lung and ovarian tumors. These data together show a better tumor-association for PDEF and suggest that PDEF is a more suitable target for developing specific cancer therapies.

DNA, Complementary↗
PubMed2004

Ultrastructural and immunohistochemical studies on Trichomonas vaginalis adhering to and phagocytizing genitourinary epithelial cells.

BACKGROUND: Trichomonas vaginalis (T. vaginalis) belongs to a common sexually transmitted disease pathogen causing genitourinary trichomoniasis in both sexes. We investigated the pathogenetic mechanism of genitourinary trichomoniasis. METHODS: Cultured T. vaginalis bodies were injected into the vaginas of rats, or incubated with genitourinary epithelial cells of female subjects, male subjects, and sperm. The ultrastructural and microscopic changes were observed via transmission and scanning electron microscopy and through microscopic histochemistry. RESULTS: Groups of T. vaginalis adhered to PAS positive columnar cells at the surface of stratified epithelium in the middle and upper portions of the vaginas. They also traversed under these cells. The parasites were shown to be PAS, cathepsin D, and actin positive, and they could release hydrolase into the cytoplasm of adhered epithelial cells. In the amebiform T. vaginalis, microfilaments were arranged into reticular formation. Similar phenomena were found during the interaction of T. vaginalis with host cells, both in vitro and in vivo. Usually several protozoa adhered to an epithelial cell and formed polymorphic pseudopodia or surface invaginations to surround and phagocytize the microvilli or other parts of the epithelial cytoplasm. Adhesion and phagocytosis of sperm by the protozoa occurred at 15 - 30 minutes of incubation. Digestion of sperm was found at 45 - 75 minutes and was complete at 90 - 105 minutes. CONCLUSIONS: T. vaginalis tends to parasitize at the fornix of the vagina, because this is the site where columnar cells are rich in mucinogen granules and their microvilli are helpful for adhesion and nibbling. T. vaginalis possesses some invading and attacking abilities. Shape change, canalization, encystation, phagocytosis, digestion, the cell coat, cytoskeleton, and lysosome all play important roles in the process of adhesion. They have two methods of phagocytosis: nibbling and ingestion. Genitourinary epithelium may be injured directly by the digestive action of hydrolases, phagocytosis, and the mechanical action of pseudopodia.

Animals↗
PubMed2004

[Ultrasound-guided percutaneous microwave coagulation therapy for hepatic metastases].

OBJECTIVE: To analyze the therapeutic results and prognostic factors of hepatic metastases treated by ultrasound-guided percutaneous microwave coagulation. METHODS: Seventy-four patients with 149 nodules of hepatic metastases were given percutaneous microwave coagulation therapy. The longest diameter of the metastatic nodule ranged from 0.7 - 6.8 cm (mean, 3.1 +/- 1.8 cm). The cumulative survival rate was analyzed by Kaplan-Meier method and the difference between groups was compared with log-rank test. Cox proportional hazard model was used to determine potential prognostic variables. RESULTS: The follow-up period for the 74 patients was 5 - 83 months (mean, 25.1 +/- 11.4 months). The overall 1-, 3-, and 5-year cumulative survival rates were 91.4%, 46.4% and 29.0%, respectively. The log-rank test showed that number of metastases, tumor size, tumor cell differentiation and local recurrence or new metastases were statistically significant prognostic factors; while age, sex and site of primary tumors were not significant prognostic factors. Multivariate analysis revealed that tumor differentiation, number of metastases and recurrence or new metastases were statistically significant prognostic factors. CONCLUSION: Ultrasound-guided percutaneous microwave coagulation therapy for hepatic metastases in patients with single metastasis, well-differentiated tumor, and without recurrence and new metastases could achieve long-term survival.

Adult↗
PubMed2004

[The influence of c-Myc, Ki-67, MMP-2 and VEGF expression on the prognosis of hepatocellular carcinoma patients with tumor resection].

OBJECTIVES: To explore the effect of c-Myc, Ki-67, MMP-2 and VEGF expression on prognosis of hepatocellular carcinoma (HCC) patients who had tumor resection. METHODS: Primary HCC patients who underwent tumor resection were retrospectively analyzed. The maximum size of their mononodular tumors was less than 5 cm, and no intrahepatic arterial chemotherapy was performed before the resections. They were followed up after resection and the time of recurrence was recorded. They were divided into 2 groups: group A (15 cases): tumor recurred within 1 year after tumor resection; group B (15 cases): with tumor recurrence after 2 years or without it. Paraffin sections of the tumors were remade from their old blocks. Immunohistochemistry stainings were performed with c-Myc, Ki-67, MMP-2 and VEGF monoclonal antibodies. Staining intensity of the tumor and paracancer tissues was quantitatively analyzed. RESULTS: c-Myc, Ki-67, MMP-2 and VEGF expressing intensities in cancer tissues in group A were higher than those in group B, and their expressed intensities in paracancer tissue in group A and B were not significantly different. CONCLUSION: The expressions of c-Myc, Ki-67, MMP-2 and VEGF in cancer tissues of the patients are related to the recurrence of their HCC after tumor resection.

Adult↗
PubMed2003

Genomic identification and biochemical characterization of a second spermidine/spermine N1-acetyltransferase.

In the polyamine back-conversion pathway, spermine and spermidine are first acetylated by spermidine/spermine N(1) -acetyl-transferase (SSAT-1) and then oxidized by polyamine oxidase to produce spermidine and putrescine respectively. Herein we apply homology-search methods to identify novel sequences belonging to a second SSAT, SSAT-2, with a chromosomal location at 17p13.1, which is distinct from SSAT-1 at Xp22. Human SSAT-2 cDNA derived from small-cell lung carcinoma was deduced to encode a 170-amino-acid protein having 46% sequence identity and 64% sequence similarity with SSAT-1. When transiently transfected into HEK-293 cells, SSAT-1 decreased spermidine and spermine pools by approximately 30%, while, at the same time, significantly increasing putrescine, N (1)-acetylspermidine, N (1)-acetylspermine and N (1), N (12)-diacetylspermine pools. By contrast, transfected SSAT-2 had no effect on intracellular polyamine or acetylated polyamine pools. When enzyme activity was assayed on enzyme extracts from transfected cells, both SSAT-1 and SSAT-2 demonstrated much higher acetylating activity than vector-transfected cells. The data suggest that, in intact cells, SSAT-2 may be compartmentalized or it may be inefficient at low intracellular polyamine concentrations. By substituting candidate substrates in the enzyme assay, we determined that SSAT-1 shows the substrate preference norspermidine=spermidine>>spermine> N (1)-acetylspermine>putrescine, whereas SSAT-2 shows the preference norspermidine>spermidine=spermine>> N (1)-acetylspermine=putrescine. Analysis of mRNA levels in cell lines and ESTs (expressed sequence tags) from various tissues by digiNorthern (a web-based tool for virtually displaying expression profiles of query genes based on EST sequences) indicated that SSAT-1 tends to be more widely and highly expressed than SSAT-2. While SSAT-1 mRNA was inducible by polyamine analogues in a variety of cell lines, SSAT-2 was not. The existence of an active, but possibly sequestered, SSAT-2 enzyme suggests that, under certain conditions, it may be recruited into basal or perturbed polyamine metabolism.

Acetyltransferases↗
PubMed2003

DigiNorthern, digital expression analysis of query genes based on ESTs.

DigiNorthern (DN) is a web-based tool for virtually displaying expression profiles of query genes based on EST sequences. Two utilities are available: DN1 takes one query gene and quantitatively display its expression levels in tissues/organs that express the gene with comparison between normal and neoplastic status of each tissue; DN2 takes two sequences as query genes and compares their expression profiles side by side.

DNA, Neoplasm↗
PubMed2003

Genomic identification and biochemical characterization of the mammalian polyamine oxidase involved in polyamine back-conversion.

In the polyamine back-conversion pathway, spermine and spermidine are first acetylated by spermidine/spermine N1 -acetyltransferase (SSAT) and then oxidized by polyamine oxidase (PAO) to produce spermidine and putrescine respectively. Although PAO was first purified more than two decades ago, the protein has not yet been linked to genomic sequences. In the present study, we apply a BLAST search strategy to identify novel oxidase sequences located on human chromosome 10 and mouse chromosome 7. Homologous mammalian cDNAs derived from human brain and mouse mammary tumour were deduced to encode proteins of approx. 55 kDa having 82% sequence identity. When either cDNA was transiently transfected into HEK-293 cells, intracellular spermine pools decreased by approx. 30%, whereas spermidine increased 2-4-fold. Lysates of human PAO cDNA-transfected HEK-293 cells, but not vector-transfected cells, rapidly oxidized N1-acetylspermine to spermidine. Substrate specificity determinations with the lysate assay revealed a preference ranking of N1-acetylspermine= N1-acetylspermidine> N1,N12-diacetylspermine>>spermine; spermidine was not acted upon. This ranking is identical to that reported for purified PAO and distinctly different from the recently identified spermine oxidase (SMO), which prefers spermine over N1-acetylspermine. Monoethyl- and diethylspermine analogues also served as substrates for PAO, and were internally cleaved adjacent to a secondary amine. We deduce that the present oxidase sequences are those of the FAD-dependent PAO involved in the polyamine back-conversion pathway. In Northern blot analysis, PAO mRNA was much less abundant in HEK-293 cells than SMO or SSAT mRNA, and all three were differentially induced in a similar manner by selected polyamine analogues. The identification of PAO sequences, together with the recently identified SMO sequences, provides new opportunities for understanding the dynamics of polyamine homoeostasis and for interpreting metabolic and cellular responses to clinically-relevant polyamine analogues and inhibitors.

Amino Acid Sequence↗
PubMed2003

Ru2 and Ru encode mouse orthologs of the genes mutated in human Hermansky-Pudlak syndrome types 5 and 6.

Hermansky-Pudlak syndrome (HPS) is a genetically heterogeneous disease involving abnormalities of melanosomes, platelet dense granules and lysosomes. Here we have used positional candidate and transgenic rescue approaches to identify the genes mutated in ruby-eye 2 and ruby-eye mice (ru2 and ru, respectively), two 'mimic' mouse models of HPS. We also show that these genes are orthologs of the genes mutated in individuals with HPS types 5 and 6, respectively, and that their protein products directly interact. Both genes are previously unknown and are found only in higher eukaryotes, and together represent a new class of genes that have evolved in higher organisms to govern the synthesis of highly specialized lysosome-related organelles.

Adaptor Protein Complex 3↗
PubMed2003

A 49 kDa microtubule cross-linking protein from Artemia franciscana is a coenzyme A-transferase.

Embryos and larvae of the brine shrimp, Artemia franciscana, were shown previously to possess a protein, now termed p49, which cross-links microtubules in vitro. Molecular characteristics of p49 were described, but the protein's identity and its role in the cell were not determined. Degenerate oligonucleotide primers designed on the basis of peptide sequence obtained by Edman degradation during this study were used to generate p49 cDNAs by RT-PCR and these were cloned and sequenced. Comparison with archived sequences revealed that the deduced amino acid sequence of p49 resembled the Drosophila gene product CG7920, as well as related proteins encoded in the genomes of Anopheles and Caenorhabditis. Similar proteins exist in several bacteria but no evident homologues were found in vertebrates and plants, and only very distant homologues resided in yeast. When evolutionary relationships were compared, p49 and the homologues from Drosophila, Anopheles and Caenorhabditis formed a distinct subcluster within phylogenetic trees. Additionally, the predicted secondary structures of p49, 4-hydroxybutyrate CoA-transferase from Clostridium aminobutyricum and glutaconate CoA-transferase from Acidaminococcus fermentans were similar and the enzymes may possess related catalytic mechanisms. The purified Artemia protein exhibited 4-hydroxybutyrate CoA-transferase activity, thereby establishing p49 as the first crustacean CoA-transferase to be characterized. Probing of Western blots with an antibody against p49 revealed a cross-reactive protein in Drosophila that associated with microtubules, but to a lesser extent than did p49 from Artemia.

Adenosine Triphosphate↗
PubMed2003

Alcohol-mediated enhancement of postprandial lipemia: a contributing factor to an increase in plasma HDL and a decrease in risk of cardiovascular disease.

BACKGROUND: Moderate alcohol consumption increases plasma HDL and lowers cardiovascular disease risk while transiently enhancing postprandial lipemia. OBJECTIVE: We hypothesized that the alcohol-mediated increase in postprandial triacylglycerol-rich lipoproteins (TRLs) and their clearance elevate HDL cholesterol and reverse cholesterol transport. DESIGN: We determined the effect in normolipidemic humans (n = 14) of postprandial lipemia produced 4 h after a test meal (M) or a test meal + 0.5 g alcohol/kg body wt (M+A) on postprandial changes in plasma lipids and on the balance of cholesterol between TRL and the cholesterol-rich LDL and HDL fractions (CRL) or red blood cells (RBCs) in fresh and incubated plasma or blood. RESULTS: Postprandial lipemia after the M and M+A test meals caused a 56% and 89% increase in plasma triacylglycerol, a 30% and 74% increase in TRL cholesterol, and a 3.8% and 6.6% decrease in CRL cholesterol, respectively. In vitro reaction of endogenous lecithin:cholesterol acyltransferase (EC 2.3.1.43) and cholesteryl ester transfer proteins via incubation of fasting plasma samples and postprandial M and M+A plasma samples for 16 h increased TRL cholesterol by 22.8% (0.08 mmol/L), 32.6% (0.16 mmol/L), and 45.8% (0.28 mmol/L) in plasma and by 71.1% (0.27 mmol/L), 89.4% (0.45 mmol/L), and 112.5% (0.70 mmol/L) in RBC-enriched blood, respectively. After the in vitro lipolysis of TRL, the elevation of HDL cholesterol in postprandial M+A plasma, but not in postprandial M plasma, was significantly greater than in fasting plasma. CONCLUSION: The alcohol-mediated increase in postprandial TRL flux and the hepatic removal of postprandial TRL after the acceptance of cholesterol from CRL and cell membranes contribute to increased HDL cholesterol and enhancement of reverse cholesterol transport in humans.

Adult↗
PubMed2003

Percutaneous sonographically guided microwave coagulation therapy for hepatocellular carcinoma: results in 234 patients.

OBJECTIVE: The objective of our study was to evaluate the long-term results of percutaneous microwave coagulation therapy for the treatment of hepatocellular carcinoma in a large patient population. SUBJECTS AND METHODS: Survival rates were determined in 234 patients with 339 nodules of hepatocellular carcinoma who had undergone percutaneous microwave coagulation therapy (208 men, 26 women; mean age, 54.8 years; mean tumor size, 4.1 +/- 1.9 cm; range, 1.2-8.0 cm; mean follow-up period, 27.9 months). Patients were those who had been rejected as candidates for surgery by the surgery department, who fit our study's criteria, and who agreed to participate. After baseline imaging studies were performed, the patients were followed up using the same combination of imaging (sonography, CT, or MR imaging) and posttreatment biopsy. RESULTS: After percutaneous microwave coagulation therapy, color Doppler flow signals disappeared in 92.0% (263/286) of the lesions. No enhancement was apparent in 89.2% (190/213) and 89.1% (41/46) of the lesions on contrast-enhanced CT and MR imaging, respectively. Posttreatment biopsies of 194 nodules showed no evidence of surviving tumor tissue in 180 nodules (92.8%). Resections of six lesions revealed complete tumor necrosis in five. The 1-, 2-, 3-, 4-, and 5-year cumulative survival rates were 92.70%, 81.60%, 72.85%, 66.37%, and 56.70%, respectively. The relationships between survival curves and the degree of hepatocellular carcinoma tumor differentiation and between survival curves and tumor size were statistically significant (p = 0.021). No severe complications were seen. CONCLUSION: Sonographically guided microwave coagulation proved to be safe and effective for the treatment of hepatocellular carcinoma. This therapy resulted in a high percentage of cases without evidence of residual tumor and satisfactory long-term results.

Administration, Cutaneous↗
PubMed2003

Prognostic factors for percutaneous microwave coagulation therapy of hepatic metastases.

OBJECTIVE: Microwave-induced tissue coagulation is a new approach for the local ablation of hepatic metastases. The purposes of the study were to analyze therapeutic results and those influencing factors that might be used to predict survival after percutaneous microwave coagulation therapy. SUBJECTS AND METHODS. From July 1995 to March 2002, 74 patients with 149 hepatic metastases were treated with percutaneous microwave coagulation therapy under sonographic guidance. The largest metastasis in each patient ranged from 0.7 to 6.8 cm (mean, 3.12 cm; SD, 1.81 cm). Survival rates and influencing factors were analyzed. RESULTS: The cumulative survival rates of all 74 patients were 91.4% at 1 year, 59.5% at 2 years, 46.4% at 3 years, 29% at 4 years, and 29% at 5 years. Patient age (p = 0.46) and sex (p = 0.12) and site of primary malignancies (p = 0.58) were not related to prognosis, whereas tumor grade (p = 0.01), number of metastases (p = 0.00), tumor size (p = 0.03), and local recurrence or new metastasis (p = 0.00) significantly affected survival as single independent factors. Multivariate analysis revealed that tumor grade (p = 0.03), number of metastases (p = 0.025), and local recurrence or new metastasis (p = 0.04) each had a significant effect on survival. No severe complications occurred. CONCLUSION: The probability of long-term survival for patients with one or two metastases, well-differentiated tumors, and without recurrence or new metastasis may be significantly higher than for other patients.

Adult↗
PubMed2003

[Screening and identification for cDNA of differentially expressed genes in human primary hepatocellular carcinoma].

OBJECTIVE: Screening and identification of differentially expressed genes in human primary hepatocellular carcinoma(HCC). METHODS: The differentially expressed genes subtracted cDNA library of HCC constructed by suppression subtractive hybridization(SSH) technique was screened by colony in situ hybridization, then the positive clones were further screened with PCR amplification. The positive clones were sequenced and analyzed for homology in the Genbank databases with Basic Local Alignment Search Tool BLAST . The novel cDNA sequences were analyzed by Northern blot analysis. RESULTS: Thirteen positive clones were obtained, and 11 cDNA sequences were identified. Sequences of 11 cDNA showed that 6 cDNA were homologous with the genes published in Genbank and 5 cDNA were unknown genes. Northern blot indicated that 3 novel cDNA(>300 bp) were only expressed in HCC. CONCLUSION: The subtracted cDNA library constructed by SSH technique contains differentially expressed genes of HCC. Three novel cDNA sequences might be differentially expressed genes of HCC. Further screening the library and gaining the whole gene sequence may lay a foundation for identifying differentially expressed genes in HCC.

Base Sequence↗
PubMed2003

[Effect of hepatic artery embolization on the microwave coagulated area].

OBJECTIVE: To study the effect of hepatic artery embolization on the microwave coagulated area, an in vivo animal experiment. METHODS: Twenty-four suitable hepatic lobes of ten dogs were divided into two groups: microwave coagulation alone 12 lobes (control group) and hepatic artery occlusion with iodized oil and gelatin sponge particles followed by microwave coagulation 12 (experiment group). Microwave coagulation was delivered with an output of 50 W for 300 or 400 seconds with thermal needles introduced parallel to and 5 approximately 20 mm from the puncture needle. After sacrifice of the dogs, their hepatic lobes were sectioned along the puncture line. Then, the appearance and size of the coagulated area were recorded. The tissue specimens were fixed in formalin for light microscopic evaluation. RESULTS: A decline in temperature gradient was detected from the center to the periphery of the affected tissue after the application of microwave coagulation, which was sharper in the control group than in the experimental group. Single polar microwave coagulation at 50 W for 300 seconds produced a necrotic volume of 25 approximately 33 mm in longitudinal diameter and 13 approximately 22 mm in transverse diameter in control group, 33 approximately 44 mm and 24 approximately 32 mm in the experimental group. The coagulation area was slightly bigger when the duration of coagulation was 400 seconds than 300 seconds, without significant difference. CONCLUSION: Hepatic artery occlusion, inhibiting the heat loss caused by hepatic arterial blood flow, is able to significantly enlarge the necrotic volume of microwave coagulation.

Animals↗