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Biomedical subjects

Feng Liu

Publications and source records attributed to Feng Liu.

At least 217 records · Page 12Linked to original sources
PubMed2003

Expression of NGF family and their receptors in gastric carcinoma: a cDNA microarray study.

AIM: To investigate the expression of NGF family and their receptors in gastric carcinoma and normal gastric mucosa, and to elucidate their effects on gastric carcinoma. METHODS: RNA of gastric cancer tissues and normal gastric tissues was respectively isolated and mRNA was purified. Probes of both mRNA reverse transcription product cDNAs labeled with alpha-(33)P dATP were respectively hybridized with Atlas Array membrane where NGF and their family genes were spotted on. Hybridized signal images were scanned on phosphor screen with ImageQuant 5.1 software after hybridization. Normalized values on spots were analyzed with ArrayVersion 5.0 software. Differential expression of NGF family and their receptors mRNA was confirmed between hybridized Atlas Array membranes of gastric cancer tissues and normal gastric mucosa, then their effects on gastric carcinoma were investigated. RESULTS: Hybridization signal images on Atlas Array membrane appeared in a lower level of nonspecific hybridization. Both of NGF family and their receptors Trk family mRNA were expressed in gastric cancer and normal gastric mucosa. But adversely up-regulated expression in other tissues and organs. NGF, BDGF, NT-3, NT-4/5, NT-6 and TrkA, B and C were down-regulated simultaneously in gastric carcinoma in comparison with normal gastric mucosa. Degrees of down-regulation in NGF family were greater than those in their receptors Trk family. Down-regulation of NT-3 and BDGF was the most significant, and TrkC down-regulation level was the lowest in receptors Trk family. CONCLUSION: Down-regulated expression of NGF family and their receptors Trk family mRNA in gastric cancer is confirmed. NGF family and their receptors Trk family probably play a unique role in gastric cancer cell apoptosis by a novel Ras or Raf signal transduction pathway. Their synchronous effects are closely associated with occurrence and development of gastric carcinoma induced by reduction of signal transduction of programmed cell death.

Carcinoma↗
PubMed2003

[Clinical observation on treatment of multiple bone metastatic tumor of mammary cancer by combination therapy of 89Sr and Chinese herbal medicine].

OBJECTIVE: To compare the clinical curative effects between 89Sr and its combination with the Guliu recipe (GLR, a Chinese herbal medicine) in treating multiple bone metastatic tumor of mammary cancer (MBM-MC). METHODS: By adopting the random sampling and grouping method, 89Sr alone (Sr) and 89Sr combined with CHM (Sr-GLR) were used in treating 86 and 40 patients with MBM-MC respectively. The efficacy of therapy were appraised according to the degree of ostalgia relieving and quality of life (QOF) in patients, and the effect of treatment on focal bone metabolism and bone marrow hematopoietic function were compared. RESULTS: The effective rate of Sr and Sr-GLR in relieving ostalgia was 83.72% and 95.00%, respectively (P > 0.05), the QOF improving and stabilizing rate of them 80.23% and 95.00% (P < 0.05), the effective rate on focal bone metabolism 59.30% and 52.50% (P > 0.05) and their hemo-toxicity 28.00% and 30.00% (P > 0.05). CONCLUSION: Sr-GLR is a combination therapy in treating MBM-MC with good effect, it could raise the patient's QOF, enhance the ostalgia relieving effect without increasing the hemo-toxicity of treatment.

Adult↗
PubMed2003

[A multicentre comparative clinical study of uterine cavity shaped device Cu300, TCu220C and TCu380A in ten years].

OBJECTIVE: To observe the clinical effects of uterine cavity shaped device (UCD) Cu300, TCu220C and TCu380A in ten years. METHODS: Two thousand, six hundred and ninety-nine rural parous women were randomized into three groups. UCD Cu300 group had 899 cases, TCu220C group and TCu380A group each had 900 cases. Follow-up visits were performed at 3, 6, 12 months and 2, 3, 5, 10 years after insertion. RESULTS: The cumulative pregnancy rates in the 10th year for UCD Cu300, TCu220C and TCu380A were 2.56, 4.82, and 4.01 per 100 women, respectively. UCD Cu300 group was significantly lower than other two groups (P < 0.05). The expulsion rates were 4.54, 5.46 and 9.68 per 100 women, respectively. TCu380A was significantly higher than UCD Cu300 and TCu220C (P < 0.001). The rates of removal for bleeding and pain for UCDCu300, TCu220C and TCu380A were 6.71, 5.58 and 6.80 per 100 women, respectively, no statistical difference was shown. The cumulative continuation rates were 74.86, 66.22 and 63.56 per 100 women at the 10 th year, UCD Cu300 was the highest, TCu380A was the lowest (P < 0.01). CONCLUSIONS: UCD Cu300, TCu220C and TCu380A are effective for long-term contraception. They are worthy of wide spreading in rural areas.

Adult↗
PubMed2003

[Bacteriologic examination in experimental maxillary sinusitis of rabbits].

OBJECTIVE: To investigate how to induce experimental maxillary sinusitis so as to explore its bacteriologic changes. METHOD: Forty New Zealand white rabbits were divided into six groups according to different methods to create experimental sinusitis. The purulent discharge of sinus and bacteria culture is investigated in different times. RESULT: The positive rate of bacteria culture are 0%(control group), 20%(sham-operation group), 84.6% (ostia-block group), 10%(bacteria inoculation group) and 100%(ostia-block plus bacteria inoculation group). The cultivate bacteria are mainly inoculate ones when sinusitis induced shorter than 2 weeks. If maxillary sinusitis induced more than 3 weeks, the cultivate bacteria are mainly opportunistic pathogens of rabbits. CONCLUSION: Experimental maxillary sinusitis can be successfully induced by bacteria inoculation with an ostium closed. The cultivate rate of opportunistic bacteria is related to the process of sinusitis.

Animals↗
PubMed2003

[Investigation of sexual function in male kidney transplant recipients].

OBJECTIVE: To observe the change of sexual function in male kidney transplant recipients. METHODS: Sixty married males, aged 26 to 45 years, who had received kidney transplantations at least half a year before and whose serum creatinine (Scr) was under 200 mumol/L, were selected randomly in the study. Sexual functions were reviewed before and after the patients' renal failure and after kidney transplantations. The results were analyzed in Chi-Square test methods. RESULTS: Their sexual functions, significantly aggravated after renal failure, were improved after kidney transplantations, but failed to return to normal. The recipients had a common worry that their sex lives might affect the renal grafts. CONCLUSIONS: Kidney transplantations significantly improve the sexual functions of these renal failure patients. It is quite necessary to provide sexological guidance to kidney transplant recipients and their spouses.

Adult↗
PubMed2003

[FHIT gene is abnormal in tongue carcinoma cell line].

To study the alteration of FHIT gene in tongue carcinoma Tca8113 cell line, total RNA of Tca8113 cells was extracted. The transcript of the FHIT gene of the Tca8113 cell line was detected with nest RT-PCR, and DNA was sequenced. The result showed that abnormal transcript (about 247 bp) of FHIT gene was detected in the Tca8113 cell line. The sequence analysis of the aberrant cDNAs revealed deletions of exons 1-8. Therefore, the deletion of the FHIT gene in Tca8113 cell line might support the hypothesis that the FHIT gene alteration is involved in the development of tongue carcinoma.

Acid Anhydride Hydrolases↗
PubMed2003

Detection of K-ras gene mutation at codon 12 by pancreatic duct brushing for pancreatic cancer.

OBJECTIVE: To assess the diagnostic value of endoscopic pancreatic duct brushing in detecting mutation of the K-ras gene at codon 12 in cytologic specimens from patients with pancreatic cancer. METHODS: Thirty-five patients treated at Changhai Hospital, Shanghai between 1999 and 2001 were enrolled. Their cells obtained by pancreatic duct brushing during endoscopic retrograde cholangiopancreatography (ERCP) were suspended with phosphate buffer solution (PBS). DNA of the cells was extracted and mutation of the K-ras gene at codon 12 detected by means of PCR-SSCP. RESULTS: The K-ras gene mutation rate of pancreatic cancer was 70%, which was higher than that of chronic pancreatitis (14%, P<0.05). K-ras gene mutation was not found in patients with pancreatic cystocarcinoma and duodenum carcinoma. As to the location of pancreatic cancer, no significant difference was observed between the head, the body and tail. The sensitivity, specificity, accuracy of pancreatic duct brushing in detecting pancreatic cancer was 70%, 94%, and 83%, respectively. CONCLUSION: K-ras analysis of pancreatic brushing samples is helpful in the diagnosis of patients with early pancreatic cancer.

Adult↗
PubMed2003

[The effect on cilia movement of experimental maxillary sinusitis in rabbits with different propose to ostia and mucosa].

OBJECTIVE: To investigate the effect on cilia movement of experimental maxillary sinusitis in rabbits with different dispose to ostia and mucosa. METHOD: Forty New Zealand White rabbits which had been induced experimental sinusitis were divided into 3 groups according to mucosa dispose during operation. The another two groups were divided according to different dispose ostia of maxillary sinus. Activated charcoal powder was used to test mucociliary transport (MCT) of maxillary sinus. RESULT: All data had be processed statistically. MCT of rabbits before operation were faster than that after operation and both of them were faster than the sinusitis group(P < 0.01). The difference of MCT in different propose of ostia groups was not significant(P > 0.05). CONCLUSION: It's a effective method to estimate the function of cilia using activated charcoal powder to test MCT of maxillary sinus. The function of regenerate mucosa after operation is lower than normal mucosa. The difference of MCT between ostia enlarged operation and ostia patent surgery is not significant.

Animals↗
PubMed2003

[Preliminary identification of T cell epitopes on 22.6 kDa antigen of Schistosoma japonicum].

OBJECTIVE: To identify the T cell epitopes on 22.6 kDa antigen of Schistosoma japonicum (Sj22.6). METHODS: The primary structure of Sj22.6 molecule was analysed using various predictive algorithms and a panel of 4 peptides were acquired. Their oligonucleotides were designed, synthesized and inserted into the multiple cloning site of plasmid pET-32c(+). The recombinant plasmids were transformed into E. coli BL21 and identified by endonuclease digestion and sequencing. The positive clones containing the recombinant plasmids could express specific fusion proteins (trx-epitope, MW approximately 20 kDa) induced by IPTG. The fusion protein with 6 x His could be coupled with NTA resin specifically, and purified by elusion of the column with buffer containing imidazole. The purified fusion proteins were incubated with splenocytes of C3H mice and then, the proliferation of splenocytes was determined by 3H-TdR incorporation assay. RESULTS: The recombinant plasmids were constructed successfully and the positive clones containing the recombinant plasmids expressed specific fusion proteins. Three of the purified fusion proteins (P4, P5, P6) could stimulate the lymphocyte proliferation. CONCLUSION: Three T cell epitopes on Sj22.6 antigen were identified.

Animals↗
PubMed2002

Grb10 inhibits insulin-stimulated insulin receptor substrate (IRS)-phosphatidylinositol 3-kinase/Akt signaling pathway by disrupting the association of IRS-1/IRS-2 with the insulin receptor.

Grb10 has been proposed to inhibit or activate insulin signaling, depending on cellular context. We have investigated the mechanism by which full-length hGrb10gamma inhibits signaling through the insulin receptor substrate (IRS) proteins. Overexpression of hGrb10gamma in CHO/IR cells and in differentiated adipocytes significantly reduced insulin-stimulated tyrosine phosphorylation of IRS-1 and IRS-2. Inhibition occurred rapidly and was sustained for 60 min during insulin stimulation. In agreement with inhibited signaling through the IRS/PI 3-kinase pathway, we found hGrb10gamma to both delay and reduce phosphorylation of Akt at Thr(308) and Ser(473) in response to insulin stimulation. Decreased phosphorylation of IRS-1/2 may arise from impaired catalytic activity of the receptor, since hGrb10gamma directly associates with the IR kinase regulatory loop. However, yeast tri-hybrid studies indicated that full-length Grb10 blocks association between IRS proteins and IR, and that this requires the SH2 domain of Grb10. In cells, hGrb10gamma inhibited insulin-stimulated IRS-1 tyrosine phosphorylation in a dose-dependent manner, but did not affect IR catalytic activity toward Tyr(972) in the juxtamembrane region and Tyr(1158/1162/1163) in the regulatory domain. We conclude that binding of hGrb10gamma to IR decreases signaling through the IRS/PI 3-kinase/AKT pathway by physically blocking IRS access to IR.

Animals↗
PubMed2002

Self-assembly of three-dimensional metal islands: nonstrained versus strained islands.

A theoretical model for the Volmer-Weber growth of three-dimensional metal islands is proposed, with a dipolar island edge-edge interaction. The existence of such an island edge effect makes the island shape dependent on island size. Furthermore, it induces a stable island size against coarsening, leading to self-assembled islands of uniform size. The dependence of the stable island size on total film coverage is shown to be different for nonstrained versus strained islands, in the regime of strong island-island interaction.

Journal Article↗
PubMed2002

Mechanism of regulation of casein kinase I activity by group I metabotropic glutamate receptors.

Previously, we reported that (S)-3,5-dihydroxypenylglycine (DHPG), an agonist for group I metabotropic glutamate receptors (mGluRs), stimulates CK1 and Cdk5 kinase activities in neostriatal neurons, leading to enhanced phosphorylation, respectively, of Ser-137 and Thr-75 of DARPP-32 (dopamine and cAMP-regulated phosphoprotein, 32 kDa). We have now investigated the signaling pathway that leads from mGluRs to casein kinase 1 (CK1) activation. In mouse neostriatal slices, the effect of DHPG on phosphorylation of Ser-137 or Thr-75 of DARPP-32 was blocked by the phospholipase Cbeta inhibitor, the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM), and the calcineurin inhibitor cyclosporin A. In neuroblastoma N2a cells, the effect of DHPG on the activity of transfected HA-tagged CK1(epsilon) was blocked by BAPTA/AM and cyclosporin A. In neostriatal slices, the effect of DHPG on Cdk5 activity was also abolished by BAPTA/AM and cyclosporin A, presumably through blocking activation of CK1. Metabolic labeling studies and phosphopeptide mapping revealed that a set of C-terminal sites in HA-CK1epsilon were transiently dephosphorylated in N2a cells upon treatment with DHPG, and this was blocked by cyclosporin A. A mutant CK1epsilon with a nonphosphorylatable C-terminal domain was not activated by DHPG. Together, these studies suggest that DHPG activates CK1(epsilon) via Ca(2+)-dependent stimulation of calcineurin and subsequent dephosphorylation of inhibitory C-terminal autophosphorylation sites.

Animals↗
PubMed2002

Nanostressors and the nanomechanical response of a thin silicon film on an insulator.

Pseudomorphic three-dimensional Ge nanocrystals (quantum dots) grown on thin silicon-on-insulator substrates can induce significant bending of the silicon template layer that is local on the nanometer scale. We use molecular dynamics simulations and analytical models to confirm the local bending of the Si template and to show that its magnitude approaches the maximum value for a freestanding membrane. The requisite greatly enhanced viscous flow of SiO2 underneath the Si layer is consistent with the dependence of the viscosity of SiO2 on shear stress.

Journal Article↗
PubMed2002

[Laryngeal reinnervation for unilateral recurrent laryngeal nerve injuries caused by thyroid surgery].

OBJECTIVE: To explore the protocols and effects of laryngeal reinnervation for unilateral recurrent laryngeal nerve (RLN) injury caused by thyroid surgery. METHODS: Different protocols of laryngeal reinnervation were performed upon 29 patients with unilateral recurrent laryngeal nerve injury caused by thyroid surgery, just coming on to with a course of 2 years, including nerve decompression upon 8 cases, end to end anastomosis of recurrent laryngeal nerve upon 6 cases, and anastomosis of main branch of ansa cervicalis to recurrent laryngeal nerve upon 15 cases. All were been subjected to preoperative and postoperative voice recording, acoustic analysis, videolaryngoscopy, stroboscopy and electromyography. RESULTS: Nerve decompression had restored the normal functional adductory and abductory motion of the vocal cord in 5 patients with a course of less than four months. Although functional motion of vocal cord had not been recovered in three patients who received nerve decompression, 2 being with a course of longer than 4 months and one with a course of less than 4 months, and in all cases who received ansa cervicalis anastomosis and end to end anastomosis of recurrent laryngeal nerve, these procedures resulted in medialization of vocal cords except in two cases, one receiving ansa cervicalis anastomosis, and the other receiving end to end anastomosis of RLN. Acoustic parameters (Jitter, Shimmer, NNE) measured 6 months after operation of any kind all returned to normal, however, without significant difference among different groups (P > 0.05). The amplitude of evoked potential of reinnervated laryngeal muscles was significantly greater in the group of nerve decompression than in the group of end to end anastomosis of RLN and group of ansa cervicalis anastomosis (both P < 0.05). However, the amplitude of evoked potential of reinnervated laryngeal muscles between the latter two groups was not significantly different (P > 0.05). Except in one case in the end to end anastomosis of RLN group and one case in the ansa cervicalis anastomosis group, the mass and tension of the reinnervated vocal cord became much the same as the contralateral normal vocal cord and symmetric vibration of the vocal cords and physiological phonation were recovered in all cases. CONCLUSION: (1) Nerve decompression is the best procedure in laryngeal reinnervation. (2) Main branch of ansa cervicalis anastomosis and end to end anastomosis of RLN effectively restore the laryngeal vocalization. (3) Selection of the laryngeal reinnervation protocols should depend on the course, severity and type of nerve injury.

Adult↗
PubMed2002

Effect of variations in the structure of a polyleucine-based alpha-helical transmembrane peptide on its interaction with phosphatidylcholine bilayers.

High-sensitivity differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to study the interaction of an alpha-helical transmembrane peptide, acetyl-Lys2-Leu24-Lys2-amide (L24), and odd-chain members of the homologous series of n-saturated diacylphosphatidylcholines. An analogue of L24, in which the lysine residues were all replaced by 2,3-diaminopropionic acid, and another, in which a leucine residue at each end of the polyLeu sequence was replaced by a tryptophan, were also studied. At low peptide concentrations, the DSC thermograms exhibited by these lipid/peptide mixtures are resolvable into two components. One of these components is fairly narrow, highly cooperative, and exhibits properties which are similar to but not identical with those of the pure lipid. In addition, the transition temperature and cooperativity of this component, and its fractional contribution to the total enthalpy change, decrease with an increase in peptide concentration, more or less independently of phospholipid acyl chain length. The other component is very broad and predominates at high peptide concentrations. These two components have been assigned to the chain-melting phase transitions of populations of peptide-poor and peptide-enriched lipid domains, respectively. Moreover, when the mean hydrophobic thickness of the PC bilayer is less than the peptide hydrophobic length, the peptide-associated lipid melts at higher temperatures than does the bulk lipid and vice versa. In addition, the chain-melting enthalpy of the broad endotherm does not decrease to zero even at high peptide concentrations, suggesting that these peptides reduce somewhat but do not abolish the cooperative gel/liquid-crystalline phase transition of the lipids with which it is in contact. Our DSC results indicate that the width of the broad phase transition observed at high peptide concentration is inversely but discontinuously related to hydrocarbon chain length. Our FTIR spectroscopic data indicate that these peptides form a very stable alpha-helix under all of our experimental conditions but that small distortions of their alpha-helical conformation are induced in response to mismatch between peptide hydrophobic length and gel-state bilayer hydrophobic thickness. We also present evidence that these distortions are localized to the N- and C-terminal regions of these peptides. Interestingly, replacing the terminal Lys residues of L24 by 2,3-diaminopropionic acid residues actually attenuates the hydrophobic mismatch effects of the peptide on the thermotropic phase behavior of the host PC bilayer, in contrast to the predictions of the snorkel hypothesis. We rationalize this attenuated hydrophobic mismatch effect by postulating that the 2,3-diaminopropionic acid residues are too short to engage in significant electrostatic and hydrogen-bonding interactions with the polar headgroups of the host phospholipid bilayer, even in the absence of any hydrophobic mismatch between incorporated peptide and the bilayer. Similarly, the reduced hydrophobic mismatch effect also observed when the two terminal Leu residues of L24 are replaced by Trp residues is rationalized by considering the lower energetic cost of exposing the Trp as opposed to the Leu residues to the aqueous phase in thin PC bilayers and the higher cost of inserting the Trp as opposed to the Leu residues into the hydrophobic cores of thick PC bilayers.

Calorimetry, Differential Scanning↗
PubMed2002

Cloning and characterization of a testis and brain-specific isoform of mouse 3'-phosphoinositide-dependent protein kinase-1, mPDK-1 beta.

3'-Phosphoinositide-dependent protein kinase-1 (PDK-1) phosphorylates and activates members of the protein kinase AGC family and plays a key role in receptor tyrosine kinase signaling. Here we report the cloning and characterization of a splice variant of mouse PDK-1, mPDK-1 beta. The cDNA encoding mPDK-1 beta contains two alternative start codons and translation from these start codons generates proteins that are, respectively, 27 or 51 amino acid residues shorter at the amino-terminus than the previously identified PDK-1 isolated from mouse liver (now renamed mPDK-1 alpha) [J. Biol. Chem. 274 (1999) 8117]. Analysis of mouse tissues shows that mPDK-1 beta is highly expressed in the testis and various functional regions of the brain. Expression of this isoform is increased in the brain of aged mice. Both mPDK-1 alpha and mPDK-1 beta are autophosphorylated at both serine and threonine residues in vitro and showed similar levels of tyrosine phosphorylation when co-expressed with either constitutively active Src or Fyn tyrosine kinases in cells. However, the mPDK-1 isoforms showed significant differences in their response to pervanadate- or insulin plus vanadate-stimulated tyrosine phosphorylation. Taken together, our findings suggest that the two PDK-1 isoforms may be differentially regulated in cells. The specific expression of mPDK-1 beta in mouse testis and brains of aged mice also suggests potential involvement of this kinase in regulating animal spermatogenesis and aging.

3-Phosphoinositide-Dependent Protein Kinases↗