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Biomedical subjects

L Deng

Publications and source records attributed to L Deng.

At least 109 records · Page 6Linked to original sources
PubMed1999

[Inhibitory effect of phosphorothioae oligodeoxynucleotides on HBV replication and synthesis of antigen in vitro].

OBJECTIVE: To evaluate the effect of triplex forming oligodeoxynucleotides (TFO) and antisense oligodeoxynucleotides (ODNas) on the replication of HBV. METHODS: A 21mer phosphorothioate TFO (TFO21) directed at 1734nt-1754nt sites in HBV core promoter and a 21 mer phosphorothioate ODNas (ODNas21) complementory to the initiation sites of pre C RNA and pregenomic RNA were synthesized. Effect of TFO21 and ODNas21 on HBV replication and synthesis of antigen were observed in 22.1.5 cells. RESULTS: Both TFO21 and ODNas21 showed the inhibition to HBV replication and synthesis of antigen while, ODNcon (control of 21 mer phosphorothioate oligodeoxynucleotides) showed little inhibitory effects. At concentration of 10 mumol/L, TFO21 and ODNas21 inhibited the synthesis of HBsAg and HBeAg by 57.5% and 77%; 61% and 79.6%, respectively. The mixture of TFO21 and ODNas21 was more effective than TFO21 or ODNas21 alone. The inhibitions were dose-dependent. No toxicity was observed in the 22.1.5 cells treated with those oligodeoxynucleotides. CONCLUSION: Triplex forming oligodeoxynucleotides and antisense oligodeoxynucleotides were both potent inhibitor, for HBV replication and synthesis of antigen.

Antiviral Agents↗
PubMed1999

[Detailed deletion mapping of chromosome 9p21-22 in nasopharyngeal carcinoma].

OBJECTIVE: To further refine the extent of deletion on chromosome 9p21-22 in nasopharyngeal carcinoma(NPC) and provide evidence for discovering new tumor suppressor genes. METHODS: Loss of heterozygosity (LOH) on chromosome 9p21-22 was analyzed in 25 paired blood and tumor samples by using 11 high-density microsatellite polymorphic markers. RESULTS: Of the 25 cases, 17(68.0%) showed LOH at one or more loci. Higher frequencies of LOH were found at four loci: D9S161(35.0%), D9S1678(31.6%), D9S263 (33.3%) and D9S1853(33.3%). In 6 cases, contiguous stretch of allelic loss was found. CONCLUSION: The minimal common region of deletion might be defined between D9S161 and D9S1853 (approximately 2.7 cM in length) at 9p21.1, suggesting that inactivation of one or more tumor suppressor genes located in this region may be an important step in NPC.

Chromosome Mapping↗
PubMed1999

[One-time operation in infant cleft lip and palate plus alveolar process].

OBJECTIVE: To improve safety and viability of one-time operation in the therapy of cleft lip and palate and cleft alveolar process. METHODS: Under the air-vein anesthesia, one-time operations were performed in 42 patients with complete cleft lip and palate plus cleft alveolar process. After rehabilitation in ICU, all patients were put into wards, and left hospital 4-7 days after operation. RESULTS: The situation during anesthesia and operation was good. There were no statistically significant changes in blood pressure, oxygen saturation of blood, heart rate and cardiac rhythm before, during and after operation. No anesthetic accident and no complication happened. The loss of blood was about 42.7 +/- 6.5 ml and the duration of operation was about 139.2 +/- 18.6 minutes. The rehabilitation was successful after operations. First intention took place in almost all patients' incisions, and palatal fistulas appeared in only 2 cases. CONCLUSION: Under the control of provisioned pediatric anesthesia and rehabilitation, one-time complete cleft lip and palate plus cleft alveolar process closure is safe and viable.

Alveolar Process↗
PubMed1999

[Effects of anticoagulants, temperature and sex on the spontaneous activation of neutrophils in vitro].

From the view of cellular morphology and enzymic histochemistry, we used the pseudopod method and NBT test to measure spontaneous activation of neutrophils in vitro. The effects of anticoagulant, temperature, and sex on the percentage of spontaneously activated neutrophils were studied. The results suggest that heparin is a better anticoagulant than EDTA because EDTA because EDTA inhibits neutrophil activation; that a higher percentage of activated neutrophils can be obtained when incubated at 37 degrees C, compared with the percentage at 25 degrees C, and at 37 degrees C the highest percentage appears an hour earlier; and that females show a higher percentage of spontaneously activated neutrophils than males, and females' highest percentage appears an hour earlier than males'. These are of referential value for further studies.

Adult↗
PubMed1999

[A study on ovariectomized goat osteoblast culture in vitro].

Osteoblasts were isolated from the frontal parietal bone of ovariectomized goat and were confirmed by testing for multiple biological features. The results showed that the goat osteoblasts cultured had the typical morphological feature of osteoblasts, the activity of alkaline phosphatase, and the ability of calcification in vitro. Also, the results proved that these goat osteoblasts in vitro had the same function and features as those in vivo. The experimental techniques in this study have provided a useful system for researches in bone metabolism.

Alkaline Phosphatase↗
PubMed1998

[Primary study of differentially expressed cDNA sequences in cell line HNE1 of human nasopharyngeal carcinoma by cDNA representational difference analysis].

OBJECTIVE: To search differentially expressed sequences correlated with pathogenesis of human nasopharyngeal carcinoma (NPC), including the candidates of tumor suppressor genes. METHODS: cDNA representational difference analysis (RDA) was performed to isolate differentially expressed sequences between cDNA from normal human primary cultures of nasopharyngeal epithelial cells and cDNA from NPC cell line HNE1. The sources of differentially expressed products were proved by Southern blot and Northern blot. The fragments were cloned with pGEM-T easy kit and sequenced by the chain termination reaction. RESULTS: Four differentially expressed cDNA fragments were isolated in the fourth subtractive hybridization using cDNA from normal human primary cultures of nasopharyngeal epithelial cells as tester amplicon and cDNA from NPC cell line HNE1 as driver amplicon by cDNA RDA. These differential cDNA fragments revealed that they really came from the tester amplicon and were not expressed or down-regulated in the NPC HNE1 cells. Of these obtained clones, some are the fragments of the human known genes including house-keeping genes, the others are novel genes. CONCLUSION: NPC involves alteration of multiple genes. Some of known genes matched with the differentially expressed sequences have an effective suppressive ability on the carcinoma.

Base Sequence↗
PubMed1998

[Establishment of partial gene expression map of 7q32 in nasopharyngeal carcinoma and primary culture normal nasopharyngeal epithelial cells].

OBJECTIVE: To establish partial gene expression map of 7q32 in nasopharyngeal carcinoma (NPC) cell line, tissues and primary culture normal nasopharyngeal epithelial cells. METHODS: We detected the expression of 20 ESTs at 7q32 in NPC cell line HNE1,13 NPC biopsies and primary culture normal nasopharyngeal epithelial cells using differential RT PCR and Northern hybridization. RESULTS: 8 ESTs (AA188181, AA13079,N27556, AA031919, N22721, H20825, T91284, AA001936) expressed equally in both of HNE1 and primary culture normal nasopharyngeal epithelial cells; 7 ESTs (T64215, AA025822, R60014,R80002,H06688, R60192,R95096) expressed in neither of them; 3 ESTs (H19830,W72688,AA130630) overexpressed in HNE1 ; and 2 ESTs (AA070437, H90882) overexpressed in primary culture normal nasopharyngeal epithelial cells. W72688 and H19830 each overexpressed in 77%(10/13) of NPC biopsies; AA070437 down-expressed in 30.7% of NPC biopsies. CONCLUSION: Partial gene expression map of 7q32 in nasopharyngeal carcinoma cell line ,tissues and primary culture normal nasopharyngeal epithelial cells has been established. The up-regulation of W72688, H19830 and down-regulation of AA070437 may be related to the occurrence of NPC.

Blotting, Northern↗
PubMed1998

3-Pyridyloxypropanolamine agonists of the beta 3 adrenergic receptor with improved pharmacokinetic properties.

Pyridyloxypropanolamines L-749,372 (8, beta 3 EC50 = 3.6 nM) and L-750,355 (29, beta 3 EC50 = 13 nM) are selective partial agonists of the human receptor, with 33% and 49% activation, respectively. Both stimulate lipolysis in rhesus monkeys (ED50 = 2 and 0.8 mg/kg, respectively), with minimal effects on heart rate. Oral bioavailability in dogs, 41% for L-749,372 and 47% for L-750,355, is improved relative to phenol analogs.

Adrenergic beta-Agonists↗
PubMed1998

A selective human beta3 adrenergic receptor agonist increases metabolic rate in rhesus monkeys.

Activation of beta3 adrenergic receptors on the surface of adipocytes leads to increases in intracellular cAMP and stimulation of lipolysis. In brown adipose tissue, this serves to up-regulate and activate the mitochondrial uncoupling protein 1, which mediates a proton conductance pathway that uncouples oxidative phosphorylation, leading to a net increase in energy expenditure. While chronic treatment with beta3 agonists in nonprimate species leads to uncoupling protein 1 up-regulation and weight loss, the relevance of this mechanism to energy metabolism in primates, which have much lower levels of brown adipose tissue, has been questioned. With the discovery of L-755,507, a potent and selective partial agonist for both human and rhesus beta3 receptors, we now demonstrate that acute exposure of rhesus monkeys to a beta3 agonist elicits lipolysis and metabolic rate elevation, and that chronic exposure increases uncoupling protein 1 expression in rhesus brown adipose tissue. These data suggest a role for beta3 agonists in the treatment of human obesity.

Adipose Tissue, Brown↗
PubMed1998

Discovery of L-755,507: a subnanomolar human beta 3 adrenergic receptor agonist.

A study of 4-acylaminobenzenesulfonamides in a cloned human beta 3 adrenergic receptor assay resulted in the discovery of n-hexylurea, L-755,507 (22). This 0.43 nM beta 3 agonist, which is > 440-fold selective over both beta 1 and beta 2 binding, is among the most potent human beta 3 agonists reported to date.

Adrenergic beta-Agonists↗
PubMed1998

Modulation of ceramide-activated protein phosphatase 2A activity by low molecular weight aromatic compounds.

Protein phosphatase 2A (PP2A) is one of the most important and abundant serine/threonine phosphatases in mammalian tissues and plays a role in gene expression, cell division, and signal transduction. PP2A is activated by ceramide, which is produced by the hydrolysis of membrane sphingomyelin in response to a variety of stress-related stimuli. To further study the role of ceramide-mediated signal transduction in cellular processes such as senescence and apoptosis, we designed and synthesized a series of low molecular weight aromatic compounds, mainly of the isoquinolone and tetralone classes, and evaluated their ability to inhibit enzymes known to be activated by ceramide. Those enzymes studied were ceramide-activated protein kinase, protein kinase C zeta and PP2A. Of these, only PP2A was found to be inhibited. A few of the compounds inhibited both ceramide-activated as well as basal PP2A activity. In addition, several of the compounds activated PP2A by up to 300% above basal enzyme activity, but only in the presence of ceramide. Thus, modulation (both inhibition and activation) of the catatylic activity of ceramide-activated PP2A is demonstrated by certain low molecular weight aromatic compounds.

Blotting, Western↗
PubMed1998

Electrospray ionization mass spectrometric and liquid chromatographic-mass spectrometric studies on the metabolism of synthetic dynorphin A peptides in brain tissue in vitro and in vivo.

Metabolic stability of synthetic dynorphins [N-terminal fragments of dynorphin A (Dyn A)] were evaluated in vitro and in vivo. These peptides were applied at concentrations 100-1000 times higher than those of the endogenous dynorphins. Degradation kinetics of these peptides were studied in rat brain homogenate by using microbore gradient RP-LC assay, and limited information on their metabolism was obtained by electrospray ionization mass spectrometry (ESI-MS) of the isolated metabolites. In vivo cerebral microdialysis, in which the peptides were introduced via the probe placed in striatum region of the brain of the experimental animals, was used to circumvent contamination arising from autoproteolysis of brain during incubation of the samples in vitro. Metabolites of Dyn A (1-13) and Dyn A (1-11) were identified from electrospray ionization mass spectra of the microdialysates without chromatographic separation; the identification of peptides in the mixtures were supported by medium resolution ESI Fourier-transform ion cyclotron resonance MS. LC-MS was used to fully characterize the complex peptide mixture obtained after the striatal perfusion of Dyn A (1-12).

Amino Acid Sequence↗
PubMed1998

Vaccinia NPH-I, a DExH-box ATPase, is the energy coupling factor for mRNA transcription termination.

Vaccinia virus RNA polymerase terminates transcription in response to a specific signal UUUUUNU in the nascent RNA. Transduction of this signal to the elongating polymerase requires a trans-acting viral termination factor (VTF/capping enzyme), and is coupled to the hydrolysis of ATP. Recent studies suggest that ATP hydrolysis is catalyzed by a novel termination protein (factor X), which is tightly associated with the elongation complex. Here, we identify factor X as NPH-I (nucleoside triphosphate phosphohydrolase-I), a virus-encoded DNA-dependent ATPase of the DExH-box family. We report that NPH-I serves two roles in transcription (1) it acts in concert with VTF/CE to catalyze release of UUUUUNU-containing nascent RNA from the elongation complex, and (2) it acts by itself as a polymerase elongation factor to facilitate readthrough of intrinsic pause sites. A mutation (K61A) in the GxGKT motif of NPH-I abolishes ATP hydrolysis and eliminates the termination and elongation factor activities. Related DExH proteins may have similar roles at postinitiation steps during cellular mRNA synthesis.

Acid Anhydride Hydrolases↗
PubMed1998

Investigation of suramin-albumin binding by electrospray mass spectrometry.

Suramin, an organic polyanion with six sulphonic groups, is under clinical trials as an agent against hormone-refractory prostate cancer. The drug binds strongly to serum albumin. The objectives were to use electrospray to measure the molecular masses of the intact complexes of albumin and suramin to determine the number of suramin molecules bound under different molar ratios, and to investigate the binding of suramin in human serum. With albumin in excess (2:1 to 25:1 ratio), only 1 and 2 bound suramins were found; with suramin excess (2:1 to 1000:1) up to 20 bound suramin molecules/albumin were found. Up to 5 bound suramins were found in human serum with 4:1 suramin:albumin ratio, which corresponds to recommended therapeutic doses (200-300 micrograms/mL). At 8:1 ratio, which would be toxic, complexes with up to ten bound suramin molecules were found, and unreacted albumin diminished.

Humans↗
PubMed1998

A common region of allelic loss on chromosome region 3p25.3-26.3 in nasopharyngeal carcinoma.

Loss of heterozygosity (LOH) of chromosome arm 3p has been commonly observed in carcinomas of various tissues, including those of nasopharyngeal carcinoma (NPC). To determine the frequency and extent of allelic loss in NPC, we investigated 16 loci on chromosome bands 3p21-26 in 24 tumor tissues by microsatellite analysis. LOH on 3p21-26 was found in 16 of 24 (66.7%) tumors. The highest frequency of allelic loss was found in two adjacent loci, D3S1620 (11/22, 50%) and D3S1560 (9/18, 50%). Eight cases showed LOH in one contiguous region and 5 cases in more than one region. Samples 1, 3, 4, 7, 8, 10, 16, 17, 18, 19, and 22 had a contiguous stretch of allelic loss between D3S1297 and D3S1597. The smallest common LOH/deletion region seems likely to lie between D3S1297 (3p26.3-26.2) and D3S1560 (3p25.3). The allelic loss map defined here will facilitate finer mapping of putative tumor suppressor gene loci and positional cloning of such genes, which may play a role in carcinogenesis of NPC.

Adult↗
PubMed1998

[Regulatory factors of osteogenic phenotypical experession by fibroblasts in vitro].

In order to explore further the regulatory factors to the potentiality in inducing osteogenesis by fibroblasts, the fibroblasts were isolated, and purified from human skin, and were grown in incubation in the media of EGF, IL-6, TNF-alpha and BMP2 at different concentrations for two weeks, then, the markers for osteogenic features were investigated by biochemistry, histochemistry and electron microscopic observations. It was found that the combined use of TNF-alpha and BMP2 could stimulate fibroblasts to secrete alkaline phosphatase, osteocalcin and collagen, and the morphological changes of the fibroblasts were also very striking. In the extracellular matrix, the collagen fibrils, with or without periodicity, were arranged regularly or randomly oriented, and numerous minute calcium granules were interspersed among them. The fibroblasts were interwoven one on top of another in the form of multilayer structure and on the surface, there were secreting granules and piling up of calcium crystals which coalessed steadily and increased in size in forming bony nodules. It was considered that TNF-alpha and BMP2 were capable of inducing the fibroblasts to form bone.

Alkaline Phosphatase↗