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Biomedical subjects

W Lu

Publications and source records attributed to W Lu.

At least 91 records · Page 5Linked to original sources
PubMed2001

Application of selective implantation in Al0.5Ga0.5As/In0.25Ga0.75As/GaAs pseudomorphic single quantum wire structures.

A pseudomorphic Al0.5Ga0.5As/In0.25Ga0.75As/GaAs asymmetric quantum wire (QWR) structure was grown on GaAs V-grooved substrate by low pressure metal organic vapor phase epitaxy. The formation of crescent shaped QWRs at the bottom of the V-grooves was confirmed by both transmission electron microscopy and photoluminescence (PL) spectra. The temperature dependence of PL spectra demonstrated a fast decrease of the sidewall quantum well PL intensity with increasing temperature, which originates from relaxation of carriers from well to wire region. The self-aligned dual implantation technique was successfully used to selectively disable the adjacent quantum structures. Decrease of the PL intensity of QWR at 8 K was observed after selective implantation, which resulted from a decreased number of carriers relaxed from adjacent quantum structures.

Aluminum↗
PubMed2001

Ping wei san, a Chinese medicine for gastrointestinal disorders.

OBJECTIVE: To describe the dilemma that American pharmacists face when their patient uses a traditional Chinese herbal formula. Ping wei san (PWS), an agent used to treat gastrointestinal disorders, is used to illustrate the problems encountered and to identify resources on Chinese herbal medicines available to pharmacists. DATA SYNTHESIS: In the US, Chinese herbal medicine is making its way into mainstream Western medicine. Patients may discover PWS in their search for a substitute for cisapride, which was partially withdrawn from the US market in July 2000. The pharmacist may be called on to assist in the management of patients who wish to use PWS for treatment of common gastrointestinal disorders like gastritis, esophageal reflux, gastric or duodenal ulcers, and acute or chronic enteritis. As with most other Chinese herbal formulas, English-language literature about PWS is limited and is often difficult to interpret. Pharmacists who are unfamiliar with the basic principles and terminology used in traditional Chinese medical practices will need to identify sources of information about this complementary alternative practice to be able to provide pharmaceutical care for patients taking a Chinese herbal formula like PWS. CONCLUSIONS: To develop a pharmaceutical care plan for patients using a Chinese herbal medicine therapy such as PWS, the pharmacist will need to become familiar with traditional Chinese medical practices and terminology describing indications, therapeutic effects, and risks. Fortunately, resources are available to pharmacists who need assistance in interpreting information on Chinese herbal therapies so that they can appropriately manage patients using them.

Animals↗
PubMed2001

[Dynamic ECG Review & Analysis Workstation].

The integrated management and remote application of dynamic ECG data is the future of the Holter System. This article introduces a kind of Dynamic ECG Review & Analysis Workstation that includes the function of integrated management and network. It has solved well the problems of common usage, archiving, total ECG analysis and remote transmission which exist in the traditional ECG Review & Analysis Systems.

Computer Communication Networks↗
PubMed2001

[Role of conditioned growth medium for ventricular fibroblasts in promoting fibroblast collagen synthesis and proliferation].

Ventricular fibroblasts were cultured using conditioned growth medium for ventricular fibroblasts (FCGM). The rate of the total collagen synthesis of ventricular fibroblasts was measured by assaying the incorporation rate of [3H]-proline, whereas the proliferation of ventricular fibroblasts was assessed by determining the incorporation rate of [3H]-TdR and the expression of c-fos genes. FCGM significantly increased the [3H]-proline incorporation rate and [3H]-TdR incorporation rate of fibroblasts in a dose-dependent manner. Furthermore, FCGM promoted the c-fos gene expression of fibroblasts, which attained its maximum in 1 h. BQ123, an ETA receptor antagonist, partially blocked the above effects of FCGM, but AT1 receptor antagonist CV11974 and alpha-adrenergic receptor antagonist regitin did not. It is suggested that the ventricular fibroblast has an autorine function in promotion of collagen synthesis and proliferation of fibroblasts by secreting endothelin and other bioactive substances.

Animals↗
PubMed2001

[Effect of aldosterone on the secretion of endothelin by ventricular fibroblasts].

Using cell culture, radioimmunoassay for endothelin and RT-PCR, the effect of aldosterone on the endothelin secretion of ventricular fibroblasts was studied. The results showed that aldosterone (1 x 10(-7) mol/L) promoted the expression of ppET-1 mRNA, which began to increase in 2 hours and attained the highest level in 4 hours, thereafter decreased; aldosterone increased the endothelin level in ventricular fibroblasts and fibroblast conditioned growth medium (FCGM) as well, which was blocked by spironolactone (1 x 10(-6) mol/L), an aldosterone receptor antagonist. The results suggest that aldosterone can increase endothelin secretion by ventricular fibroblasts, which can be inhibited by its receptor antagonist spironolactone.

Aldosterone↗
PubMed2001

[Role of mitogen-activated protein kinase in the inhibition of myocardial hypertrophy by nitric oxide in renovascular hypertensive rats].

The aim of this study was to examine the effects of L-arginine, a nitric oxide (NO) precursor, on protein expression of endothelial nitric oxide (eNOS), nitrite/nitrate content, protein expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) and the activity of mitogen-activated protein kinase (MAPK) in cardiac tissues in renovascular hypertensive rats (RHR). The Goldblatt renovascular hypertensive model was established by two-kidney one clip method. The rats were divided into four groups, respectively treated with 50, 150 and 450 mg/kg L-arginine and 150 mg/kg L-arginine plus 10 mg/kg L-NAME (an eNOS inhibitor) (i.p.). Another group did not receive specific treatment from the 5th week after renal artery constriction. Control group was sham-operated. Mean arterial blood pressure (MABP) and the ratio of left ventricular weight to body weight (LVW/BW) were measured 8 weeks after treatment. eNOS protein expression, nitrite/nitrate content, MKP-1 protein expression and MAPK activity in cardiac tissues were detected using Western blot analysis, enzyme-reduction method and substrate in-gel kinase assay, respectively. It was found that L-arginine significantly inhibited the increase of MABP and LVW/BW, attenuated the activity of MAPK, increased protein expression of eNOS and MKP-1 and potentiated production of NO in cardiac tissue with the most effective dosage of 150 mg/kg, and these effects of L-arginine could be inhibited by L-NAME. These results suggest that MKP-1 may play an important role in the NO-induced inhibition of myocardial hypertrophy. The anti-hypertrophic effects of L-arginine may involve increase of eNOS protein expression and NO production, potentiation of MKP-1 protein expression, and inhibition of MAPK activity in the cardiac tissue of RHR.

Animals↗
PubMed2001

[Effect of natural zeolite on nutrient preserving capability of degraded slope soil in south China].

Soil column leaching experiment showed that after zeolite application, the content of nitrogen and potassium in leachate was reduced significantly, but no significant effect was detected for phosphate. This application had a positive effect on soil available nitrogen, phosphorus and potassium. It increased the content of soil AL-P and Fe-P, but did not increase the NO3-N content in leachate.

Fertilizers↗
PubMed2001

[Effect of different tillage methods on rice growth and soil ecology].

Field experiments were conducted in double-cropping rice field in South China during 1998-1999 to study the effect of different tillage methods on rice growth and soil ecology. The results showed that with rice scattering planting, no-tillage method caused a reduction of rice tillering, effective panicle, and filled grains of rice. Grain yield under no-tillage was 13.40% lower than that under conventional tillage, and the economic benefits decreased by 10.9%. Soil analysis showed that in no-tillage fields, soil bulk density and hardness were increased, soil porosity and available P and K were decreased, the amount of actinomyces and fungi was reduced, while that of soil bacteria was increased, and the enzyme activity was promoted. Minimum tillage and conventional tillage had similar soil physical and chemical properties, soil microbial quantity and enzyme activity. Minimum tillage could produce a 2.1% higher grain yield than conventional tillage, and increase the economic benefits by 11.0%.

Agriculture↗
PubMed2001

Growth inhibition of interleukin-2 receptor gene-transduced peripheral blood lymphocytes on human ovarian cancer cells.

OBJECTIVE: To investigate the growth inhibition of interleukin-2 receptor (IL-2R) gene-transduced peripheral blood lymphocytes (PBLs) on human ovarian cancer cells. METHODS: Interleukin-2 (IL-2) and IL-2R genes were transfected into human ovarian cancer cell line 3AO and PBLs, respectively, using the same Fugene vector. Twenty-four hours later transfected and nontransfected PBLs were cocultured with transfected and nontransfected 3AO for 48 hours. cytotoxicity of PBLs on 3AO was detected by the MTT assay. RESULTS: The morphology of IL-2-transduced 3AO and IL-2R-transduced PBLs remained unchanged. 3AO cells could be transfected with the IL-2 gene and expressed IL-2 mRNA, and PBLs could be transfected with the IL-2R gene and expressed IL-2R mRNA. IL-2 transduced 3AO cells enhanced their response to the cytotoxicity of PBLs. Furthermore, growth inhibition of PBLs to 3AO cells increased significantly when the IL-2R was transfected into PBLs and when the IL-2 gene was transfected into 3AO cells and the two were combined. CONCLUSIONS: IL-2R gene transduced PBLs are able to enhance their cytotoxicity on IL-2 gene transduced ovarian cancer cells. This method may be a new way to investigate IL-2 gene therapy for ovarian cancer.

Cell Count↗
PubMed2001

[Down-regulation of ETA receptor of vascular smooth muscle cells by 17 beta-estradiol].

In the present study, the effects of 17 beta-estradiol on vascular reactivity of ovariectomized rats and proliferation of cultured rat aortic smooth muscle cells were studied. The vascular reactivity was significantly increased in ovariectomized rats compared with the sham-operated animals. The selective ETA receptor antagonist BQ123 inhibited the increase in [3H]-TdR incorporation in response to ET-1 on vascular smooth muscle cells (VSMCs). 17 beta-estradiol also attenuated the ET-1 effects in a dose-dependent manner. The results of RT-PCR and Western blot show that expression of ETA receptor was decreased after treatment with 17 beta-estradiol. The effect of 17 beta-estradiol was partially inhibited by estrogen receptor antagonist tamoxifen. The above results demonstrate that proliferation of VSMCs stimulated by ET-1 was mainly mediated through ETA receptor. Due to the down-regulation of ETA receptor and mediation of estrogen receptor, 17 beta-estradiol inhibits the ET-1-induced proliferation of VSMCs and decreases the vascular reactivity of ovariectomized rats.

Animals↗
PubMed2001

[Excimer laser in situ keratomileusis for severe ametropia after penetrating keratoplasty].

OBJECTIVE: To evaluate the effects of excimer laser in situ keratomileusis in correcting severe myopia and astigmatism after penetrating keratoplasty. METHODS: Excimer laser in situ keratomileusis was performed on ten eyes of ten patients to correct high ametropia in cases having previously undergone penetrating keratoplasty. RESULTS: After surgery, all grafts remained clear and no corneal graft rejection occurred during the follow-up period. The average spherical equivalent refraction decreased from minus sign11.85 D preoperatively to minus sign3.38 D postoperatively and the average cylinder from 6.75 D to 2.70 D. The highest cylinder correction achieved was 10.00 D. The mean uncorrected visual acuity improved from 0.1 to 0.8, the best one was 1.5, and the best corrected visual acuity (BCVA) improved from 0.8 to 1.1. In this group, BCVA was improved in all eyes. CONCLUSION: Excimer laser in situ keratomileusis is a safe and effective method to deal with the high ametropia after penetrating keratoplasty and shows its great prospect.

Adult↗
PubMed2001

[Pathomorphologic features of clinical stage A prostate carcinoma and causes for misdiagnosis and missed diagnosis].

OBJECTIVE: To study the pathomorphologic features and causes for misdiagnosis and missed diagnosis of clinical stage A prostate carcinoma. METHODS: Prostate samples from a series of 1 020 prostate resections performed in five Shanghai hospitals were obtained, from which 50 clinical stage A carcinoma were studied by immunohistochemistry, according to tumor differentiation and their volume, they were divided into stage A1 and A2 disease. The pathomorphologic features of stage A1 and A2 disease were compared, and the causes for misdiagnosis were analysed. RESULTS: Stage A1 cancer were well- or moderately well-differentiated, of low volume and tended to be multifocal; Stage A2 cancers were poorly differentiated, of high volume, diffuse infiltration and with high grade prostatic intraepithelial neoplasia. 8 cases were misdiagnosed of which 7 cases were stage A1 and misdiagnosed as benign proliferous small gland lesions and 1 case of A2 disease was misdiagnosed as epithelioid histiocytic reactive proliferation. CONCLUSIONS: Stage A1 cancer tended to be initiated in the transition zone and the central zone of the hyperplastic prostate. Stage A2 cancers were mostly middle grade to high grade cancers initiated in the peripheral region and then invaded the central area. The lower incidence of stage A carcinoma in China is related to the small amount of biopsy tissue, careless microscopic observation, or lack of the ability to diagnose stage A1 cancer.

Aged↗
PubMed2001

[Study on cadmium-induced hepatocellular apoptosis in rats].

The effect of cadmium chloride on hepatocellular apoptosis in rats was studied in vivo at the doses of 5, 10 and 20 mumol/kg by using TUNEL (TdT-mediated dUTP Nick End Labelling), DNA ladder electrophoresis and flow cytometry. The results showed that TUNEL-positive cells could be detected in cadmium-treated rat liver cells. DNA fragmentation (ladder pattern) in cadmium-treated liver cells could be displayed by agarose gel electrophoresis. The rates of apoptotic cells in the liver of cadmium-treated rats at these doses were higher than those of control rats significantly. It was suggested that cadmium chloride could induce hepatocellular apoptosis of rats at certain doses in vivo.

Animals↗
PubMed2001

[Study of quantitative calibration model suitability in near-infrared spectroscopy analysis].

Near-infrared spectroscopy is a fast, high efficiency and low cost analytical technique, that depended on analytical models which are built through near-infrared spectra, the primary method results of calibration set and chemometrics methods. The reliability of analytical results mostly depends on the suitability of analytical model to unknown samples. To judge the suitability of analytical model, a new method is presented that combine principle factor analysis (PCA) and Mahalanobis distance. It is different with traditional method, that the Mahalanobis distance is calculated through PCA factor scores. It can avoid the wavelengths selection problem in traditional method of spectral Mahalanobis distance. Through the determination of cetane number of diesel fuel, some factors that affect model suitability judgement are discussed.

Calibration↗
PubMed2000

Temperature-sensitive mutants of p53 homologs.

Two homologs of the p53 tumor suppressor, p63 and p73 have recently been discovered. These proteins have activities similar to p53 in cell culture but have distinct developmental functions in vivo. We found that temperature-sensitive mutants of certain p63 and p73 isoforms can be created by single amino acid substitutions of an alanine residue corresponding to alanine 135 of murine p53. The mutants (p63gamma-Pro167, p73alpha-Leu156 and p73beta-Ile156) can be controlled by temperature shift between 32 degrees C and 39 degrees C. They can be stably expressed in p53-null H1299 cells at 39 degrees C, become transcriptionally activated at 32 degrees C, and induce expression of p53-responsive genes MDM2 and p21WAF1. Activation of p73beta-Ile156 in H1299 cells inhibits cell division but induces significant increase in cell size (hypertrophy), whereas activation of p73alpha-Leu156 and p63gamma-Pro167 induces apoptosis. These mutants may be useful tools for gaining further insight to the functions of p53 homologs.

Amino Acid Sequence↗
PubMed2000

Identification of impurities affecting commercial ethylene glycol UV transmittance.

As a raw material for making polyesters, ethylene glycol has a special specification of UV transmittance. At present, ethylene glycol produced by some plants still has low UV transmittance rendering it unsuitable for use in polyester production. In this paper, a method was developed for the identification of the impurities that cause commercial ethylene glycol to have low UV transmittance, using solid-phase extraction (SPE) and some analytical techniques such as high-performance liquid chromatography, gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy. The major UV-absorbing impurities were identified as some alkyl homologues of 2-hydroxycyclopent-2-en-1-one, including 2-hydroxy-3,5-dimethylcyclopent-2-en-1-one, 2-hydroxy-3-methylcyclopent-2-en-1-one, 2-hydroxy-3,4-dimethylcyclopent-2-en-1-one, 2-hydroxy-3-ethyl-4-methylcyclopent-2-en-1-one and 2-hydroxy-3-ethylcyclopent-2-en-1-one. Their concentrations were estimated to be less than 2 microg ml(-1). It is believed that with the above results, ethylene glycol-producing plants might make process improvements to remove these impurities more effectively and more easily.

Chromatography, High Pressure Liquid↗