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Biomedical subjects

R Wu

Publications and source records attributed to R Wu.

At least 109 records · Page 6Linked to original sources
PubMed2000

Expression and regulation of a molecular marker, SPR1, in multistep bronchial carcinogenesis.

A small proline-rich protein, SPR1, is overexpressed in squamous metaplasia of bronchial epithelium. We studied the expression and regulation of SPR1 in a series of human bronchial epithelial cell lines representing a model of multistep bronchial carcinogenesis. These cell lines included a primary culture of tracheobronchial epithelial cells (HTBE), a papilloma virus-transformed tracheobronchial epithelial cell line (HBE1), a cell line selected from HBE1 by a tobacco carcinogen and a phorbol ester (HBE1-C), a simian virus-transformed bronchial epithelial cell line (BEAS-2B), and a lung carcinoma cell line (H460). Different tumorigenic potentials of these cell lines were indicated by graded levels of telomerase activity. Concomitant with squamous transformation, there was an increase in SPR1 expression in HTBE, HBE1, and HBE1-C that was reversible by vitamin A. With progression of tumorigenicity, there was a marked reduction in SPR1 expression in BEAS-2B and a total loss of expression in H460. In these latter cell lines representing advanced malignant transformation, there was a loss of up- and downregulation, respectively, by the phorbol ester and vitamin A. Transfection study with chimeric constructs of the SPR1 promoter and a reporter gene showed that the dysregulation of SPR1 expression in malignant transformation was a result of perturbation of the basal and enhancer elements of the first 162 nucleotides in the 5'-flanking promoter region of the SPR1 gene. These findings suggest an association of transcriptional dysregulation of the SPR1 gene with multistep bronchial carcinogenesis.

Animals↗
PubMed2000

A novel mechanism of retinoic acid-enhanced interleukin-8 gene expression in airway epithelium.

A 3- to 8-fold stimulation of interleukin (IL)-8 gene expression by all-trans-retinoic acid (ATRA) was demonstrated in primary cultures of human and monkey tracheobronchial epithelial cells and BEAS-2B serum-sensitive cell line. The effect of ATRA on IL-8 gene expression is dose- and time-dependent. Using cycloheximide, it was observed that new protein synthesis was required for the stimulation. ATRA had no effect on IL-8 messenger RNA stability. A difference in nuclear run-on activity suggests that a transcriptional mechanism is involved in ATRA-enhanced IL-8 gene expression. Promoter-reporter gene transfection studies demonstrated ATRA enhanced IL-8 promoter activity, especially when cells were cotransfected with retinoic acid nuclear receptor-alpha expression vector. Deletion and site-directed mutagenesis analysis revealed the involvement of nuclear factor (NF)-kappaB binding site of the IL-8 gene in ATRA-enhanced promoter activity. Electrophoretic mobility shift assay (EMSA) demonstrated that ATRA enhanced DNA-NF-kappaB complex formation, especially with the p65 subunit. Western blot analysis demonstrated that ATRA did not enhance the protein amount of both the p50 and the p65 subunits in the nuclei. Because ATRA also enhances thioredoxin (TRX) gene expression, the effect of TRX on IL-8 gene expression was examined. IL-8 promoter activity was enhanced in transfected cells by the addition of TRX protein. Treatment of nuclear extracts with TRX also enhanced DNA- NF-kappaB complex formation as observed by EMSA, particularly the p65 subunit. Taking these data together, a novel mechanism is proposed in which ATRA activates promoter activity of IL-8 gene through TRX-dependent NF-kappaB activation.

Animals↗
PubMed2000

Induction of cell cornification and enhanced squamous-cell marker SPRR1 gene expression by phorbol ester are regulated by different signaling pathways in human conducting airway epithelial cells.

Phorbol ester is a strong inducer for both cell cornification and squamous-cell marker SPRR1 gene expression in conducting airway epithelial cells. However, the signaling pathways involved in the regulation of both events have not been completely elucidated. The current study focuses on the common and divergent pathways involved in the induction of these two activities by phorbol-13-myristate-12-acetate (PMA). Using a protein kinase (PK) C inhibitor, bisindolylmaleimide I, PMA-induced cell cornification and SPRR1 gene expression were abolished. Further, a PKC activator, indolactam V, induced cell cornification in the absence of PMA treatment. These results suggest a PKC-dependent signaling pathway for both gene induction and enhanced cell cornification by PMA. However, a mitogen-activated protein kinase-specific inhibitor, PD98059, could only block the gene induction event but failed to prevent cell cornification induced by PMA. These results suggest that diverse signaling pathways after PKC activation by PMA are involved in the regulation of these two events.

Biomarkers↗
PubMed2000

Experimental study of the effect of external counterpulsation on blood circulation in the lower extremities.

A bidirectional ultrasonic Doppler flowmeter with direct single sideband separation was used to measure blood flow in the femoral and dorsalis pedis arteries of 18 normal volunteers. Changes in blood-flow velocity and volume during external counterpulsation (ECP) with various sustaining times (the time for maintaining pressure) for inflation were studied. The results showed that blood-flow velocity in the femoral and dorsalis pedis arteries is increased significantly by ECP, but the change is not closely related to the duration of inflation. For a short sustaining time, the net forward blood-flow volume in arteries increased remarkably, but at longer sustaining times it dropped back significantly to a value even lower than that before ECP. The sustaining time for inflation to produce the maximum net forward flow volume (the optimal sustaining time of inflation) was found to be at one-quarter to one-third of the cardiac cycle. In a second study, changes in the calibre of the femoral artery and its collateral and anastomotic branches in the hind extremities in 5 dogs before and after ECP with an optimal sustaining time of inflation were examined by femoral arteriography. The experiments showed that the patency of collateral and anastomotic branches of the femoral artery was greater before than after ECP. The study suggests that ECP could be an effective treatment for improving the blood circulation in extremities.

Adult↗
PubMed2000

Loss of fhit expression in invasive cervical carcinomas and intraepithelial lesions associated with invasive disease.

Allelic losses involving chromosome 3p are frequently observed in cervical cancers. Deletion mapping studies of primary cervical carcinomas have localized common regions of deletion to 3p14.2 and 3p21. The candidate tumor suppressor gene FHIT has been mapped to 3p14.2, and previous studies have demonstrated reduced or aberrant FHIT transcripts and reduced or absent Fhit protein expression in a large percentage of cervical cancer-derived cell lines and primary cervical carcinomas. To expand these observations to preinvasive cervical epithelial lesions and to determine whether loss of Fhit protein expression might be associated with tumor progression, immunohistochemical methods were used to examine Fhit expression in 95 invasive cervical carcinomas, 33 high-grade squamous intraepithelial lesions (HSILs) associated with concurrent invasive cancer, 38 HSILs unassociated with invasive cancer, 24 low-grade squamous intraepithelial lesions, and 22 normal cervix samples. All normal cervical epithelia and low-grade squamous intraepithelial lesions exhibited diffuse cytoplasmic immunostaining of moderate to strong intensity. Fhit protein expression was markedly reduced or absent in 67 of 95 (71%) invasive cancers, 17 of 33 (52%) HSILs associated with invasive cancer, and 8 of 38 (21%) HSILs without associated invasive cancer. The results confirm that Fhit protein expression is reduced or absent in the majority of cervical carcinomas and suggest that loss of Fhit expression often accompanies cervical tumor progression. Moreover, absent or reduced Fhit protein is observed at a significantly higher frequency in HSILs associated with progression to invasive cancer than in HSILs with unknown risk for progression (P = 0.012). These findings suggest that loss of Fhit expression in HSILs could serve as a useful marker of high-grade preinvasive lesions that have an increased likelihood of progression to invasive carcinoma.

Acid Anhydride Hydrolases↗
PubMed2000

[Reconstruction of anus in low rectum cancer operation].

OBJECTIVE: While low rectum cancer being resected with Mile's operation, the anus was reconstructed in situ simultaneously. METHODS: Thirty cases of artificial anus were perfectly reconstructed in situ with transferring of the gracilis and invaginating of the end of the sigmoid for the outer and inner sphincter of the anus. The artificial rectum valve was used for the rectum angle. RESULTS: The rate of excellent and good operative results reached 90.63%. CONCLUSION: The results show that this method is suitable for radical operation of low rectum cancer and functional incapacitation of the anus from other diseases as well.

Adenocarcinoma, Mucinous↗
PubMed2000

[Apoptosis of endothelial cells in alteration of microvascular permeability in lung during sepsis].

OBJECTIVE: To investigate the apoptosis of endothelial cells in the alteration of microvascular permeability in lung during sepsis. METHODS: Twenty-four male NIH mice were subjected to cecal ligation and puncture (CLP) or sham operation (SO). The microvascular endothelial cells of the lungs were harvested at 3 hours and 12 hours after operation. The apoptosis of endothelial cells (VIII factor related antigen positive cells) in the lungs was determined by 2-color flow cytometry (FITC-labeled VIII factor related antigen and PI) and Apop Tag) in situ apoptosis detection kit in situ. The apoptosis related gene (bcl-2) was detected by RT-PCR. The microvascular permeability in lung tissue was also examined. RESULTS: The apoptosis of microvascular endothelial cells was increased significantly at 12 hours after CLP (5.03 +/- 0.92 vs. 3.48 +/- 1.21, P < 0.05). The increased apoptosis was paralleled with the decrease in bcl-2 gene expression. The microvascular permeability in lung tissue was slightly increased at 3 hours after CLP, but significantly increased at 12 hours after CLP (0.106 +/- 0.008 vs 0.047 +/- 0.003, P < 0.01). CONCLUSIONS: Apoptosis in microvascular endothelial cells seems to be an important reason for the alteration of microvascular permeability.

Animals↗
PubMed2000

[Combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy for cataract patients with glaucoma].

OBJECTIVE: To evaluate the therapeutic effects and safety of the combined phacoemulsification, foldable intraocular lens implantation and trabeculectomy (triple procedure) and compare the outcomes of the operation with two different small incisions, conventional scleral flap and scleral tunnel flap. METHODS: Triple procedure was performed through a 3.5 mm incision by means of conventional scleral flap or scleral tunnel flap on 44 eyes of 42 patients with cataract and glaucoma. RESULTS: After follow-up for 3 -- 6 months, the mean intraocular pressure (IOP) was (14.33 +/- 3.68) mm Hg (1 mm Hg = 0.133 kPa) with a mean pressure reduction of 10.35 mm Hg from that before the operation (P < 0.001). Postoperatively, the visual acuities were >or= 0.5 in 33 eyes (75.0%) at 1 week and in 37 eyes (84.1%) during 3 - 6 months. The mean postoperative astigmatism was (1.29 +/- 0.93) D at 1 week and only 0.17D more than the mean preoperative one (P > 0.05). There was also no statistical difference between the mean preoperative astigmatism and postoperative astigmatism at 3 - 6 months, which was (1.12 +/- 0.73) D. The filtering blebs of type I and II (functional) by Kronfeld's classification presented in 79.5% of the eyes and type III (non-functional) in 20.5% of the eyes. There were no statistical differences for the postoperative outcomes of IOP, visual acuity, astigmatism and filtering bleb between two different procedure groups (P > 0.05). CONCLUSIONS: The triple procedure is an effective, quick, repeatable and safe procedure for cataract patients with glaucoma. There are no differences at the surgical outcomes of two different incisions by means of the conventional scleral flap vs scleral tunnel flap.

Adult↗
PubMed2000

[Adherence of bovine lens epithelial cells to the surface of intraocular lens made of different materials].

OBJECTIVE: To compare the in vitro adherence of bovine lens epithelial cells (BLEC) onto the surface of intraocular lens (IOL) made of 4 different materials: polymethylmethacrylate (PMMA), silicone (SI), hydroxyethylmethacrylate (HEMA) and acrylic (Acrysof, ACRY). METHODS: BLEC were incubated with IOLs four 48 hours. Adherent cells were counted by flow cytometry technique. RESULTS: The amount of the adherent cells on IOLs of ACRY was the highest, that of HEMA the least, and there was no significant difference between the amount on PMMA and SI IOLs (P > 0.05). CONCLUSIONS: Adherence of lens epithelial cells to IOLs is influenced by the surface property of IOL materials, which may influence the occurrence of postoperative capsular opacification after IOL implantation.

Animals↗
PubMed2000

[Some differences on biological characteristics of Campylobacter jejuni].

Fecal samples from 195 diarrheic patients in different age, rectal and cloacal swabs from 656 normal and diarrheic animals and poultry, 108 visceral materials from the dead animals with diarrhoea were cultured for Compylobacter jejuni. A total of 458 strains of campylobacters (445 strains of C. jejuni, 13 strains of C. coli) were isolated and identified, and some biological characteristics of these strains were observed. Lior's biotyping scheme was used for biotyping 354 strains of campylobacters(253 strains of C. jejuni and 2 strains of C. coli). The results showed the most biological characteristics of these campylobacters accorded with that previously described in the literatures, but it were also found that there were some differences on morphological, cultural, physiological and biochemical characteristics and antibiotic resistances. In these differences, the most main differences were that 48.3% (215/445) of C. jejuni and 23.1% (3/13) of C. coli were resistant to nalidixic acid, and that 1.1% (5/445) of C. jejuni and 7.6(1/13) of C. coli were resistant to cefotaxime. There were relationships between antibiotic resistances and strain sources (P < 0.005). The result of biotyping 352 strains of C. jejuni indicated that biotype I (40.9%) and II (58.2%) were predominant in the bodies of these animals, and there were two biotypes distributed in the body of same animal.

Animals↗
PubMed2000

[Study on the physicochemical properties of Campylobacter jejuni enterotoxin].

Precipitate of Campylobacter jejuni cytotonic enterotoxin(CE) performed in an 80% saturated solution of ammonium sulfateit indicated that there were some little molecular proteins except the 68 kD main band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE), whereas the eluate from GM1 ganglioside affinity column chromatography exhibited only one 68 kD band on SDS-PAGE. The results suggest that CE mainly be consisted of 68 kD protein. The toxin is heat-labile, pH dependent and resistant to trypsin, It could be completely inactivated by heating at either 56 degrees C and 60 degrees C for 30 min or 100 degrees C for 15 min. The activity was maximum at pH 6.0 and was completely inactivate at pH 3.0 and pH 9.0, and rapidly reduced after storage over 3 d at 4 degrees C. The anti-LT serum could completely inhibited the activity of CE.

Animals↗
PubMed2000

[The degradation performance of bioabsorbable acylchitin fiber reinforced PLA composite materials in vitro and in vivo].

The present authors have investigated the degradation performance of acylchitin fiber reinforced polylactide composite materials plates both in vitro and in vivo. The initial flexural strength and the initial flexural modulus of this plate are 114.72 MPa and 3980.05 MPa, respectively. The flexural strength of this plate decreases to 31.42 MPa after the plate has been submerged in injectio natrii lactatic ringeri tissue fluid for a period of 16 weeks at 37 degrees C. Both the in vitro degradation performance and the strength retention of this plate are better than those of the self-reinforced PGA/PLA and PGA, though the initial strength of the latter two being much higher than that of the former. The degradation products of the chitin/PLA composite materials can be absorbed by metabolic pathway.

Animals↗
PubMed2000

[Study on neodymium complexes by broad wavelength range photoacoustic spectroscopy].

Neodymium complexes were studied by photoacoustic(PA) spectroscopy from UV-Vis to mid-IR. According to the PA spectra, low excited energy levels, relaxation processes and fluorescence properties were discussed. Then the influence of interaction between Nd(III) and ligands in solid complexes was investigated on the basis of band shifts and intensity change.

Chelating Agents↗
PubMed2000

[Study on the photoacoustic phase of rare earth complexes].

The theory of the photoacoustic (PA) phase has been studied. The PA phase spectra of rare earth complexes with dibenzoylmethide have been explained basing on the theory. The phase shifts of Tb complexes at the ligand absorption peak have been calculated. The phase shifts and their intramolecular relaxation processes have been studied also.

Acoustics↗
PubMed2000

[Determination of trace Pb in heme chloride by ICP-AES].

In this paper, a method for the determination of trace Pb in heme chloride is studied. The matrix matching and background climinating methods are used to minimize interference. The spectral interferences of matrix elements to analytical line of detected element are also discussed. The rate of recovery is between 95%-107% and RSD is less than 2%. The detertion limit is 17 ng.mL-1. According the comparison to the methods of some samples decomposition, choose one best method. The samples have been got pleased result.

Hemin↗
PubMed1999

Effects of corticosteroid, contrast medium and ATP on focal microcirculatory disorders of the cochlea.

We evaluated the ability of various drugs to prevent the decrease in focal cochlear blood flow induced by photochemical reaction and investigated the mechanisms underlying this decrease. By means of a photochemical reaction, which produces reactive oxygen species, focal lesions measuring about 1 mm in diameter were induced in the lateral wall of the guinea pig cochlea. The protective effects of hydrocortisone, amidotrizoate and ATP on cochlear blood flow and cochlear vascular conductance changes were evaluated by using a non-contact laser flowmeter. Cochlear blood flow and cochlear vascular conductance were decreased to 65.1+/-4.9% (mean +/- S.E.M.) and 57.0+/-3.7% (mean +/- S.E.M.) of the initial level 30 min after the start of the photochemical reaction, respectively. Hydrocortisone significantly prevented the decline in the cochlear blood flow and cochlear vascular conductance and reduced the area of stria vascularis degeneration in a dose-dependent manner. Neither amidotrizoate nor ATP significantly prevented the decrease in cochlear blood flow or cochlear vascular conductance. Hydrocortisone was more effective than vasodilators or other agents which increase cochlear blood flow in preventing the photochemically induced decrease in cochlear blood flow. This might be due to the antioxidative effects of hydrocortisone.

Adenosine Triphosphate↗
PubMed1999

Molecular genetic evidence supporting the clonality and appendiceal origin of Pseudomyxoma peritonei in women.

Pseudomyxoma peritonei (PMP) is a poorly understood condition characterized by mucinous ascites and multifocal peritoneal mucinous tumors. Women with PMP often have mucinous tumors involving both the appendix and the ovaries. Several previous histopathological and immunohistochemical studies of PMP have suggested that most, if not all, cases of PMP in women are derived from mucinous adenomas of the appendix rather than from primary ovarian tumors. A few studies of the molecular genetics of PMP have been recently reported. However, these studies analyzed only a small number of cases and some included a heterogeneous group of mucinous tumors, including both benign and malignant appendiceal and ovarian tumors. We analyzed K-ras mutations and allelic losses of chromosomes 18q, 17p, 5q, and 6q in a substantial number of morphologically uniform cases of PMP with synchronous ovarian and appendiceal tumors as well as in appendiceal mucinous adenomas (MAs) and ovarian mucinous tumors of low malignant potential (MLMPs) unassociated with PMP. Each of the 16 PMP cases (100%) analyzed demonstrated identical K-ras mutations in the appendiceal adenoma and corresponding synchronous ovarian tumor. K-ras mutations were identified in 11 of 16 (69%) appendiceal MAs unassociated with PMP and in 12 of 16 (75%) ovarian MLMPs unassociated with PMP. Two PMP cases showed identical allelic losses in the matched ovarian and appendiceal tumors. A discordant pattern of allelic loss between the ovarian and appendiceal tumors at one or two of the loci tested was observed in six PMP cases. In all but one instance, LOH was observed in the ovarian tumor, whereas both alleles were retained in the matched appendiceal lesion, suggesting tumor progression in a secondary (metastatic) site. Our findings strongly support the conclusion that mucinous tumors involving the appendix and ovaries in women with PMP are clonal and derived from a single site, most likely the appendix.

Adenoma↗