Biomedical subjects

L Wang

Publications and source records attributed to L Wang.

At least 1,153 records · Page 64Linked to original sources

PubMed1999

[Ameloblastic fibrosarcoma: an immunohistochemical and ultrastructural study of the mesenchymal component].

To study the characteristics of the mesenchymal cells of ameloblastic fibrosarcoma (AFS), three cases of AFS were studied immunohistochemically and ultrastructurally. The results showed that the mesenchymal component of AFS consisted predominantly of fibroblastic cells with a small number of undifferentiated cells, a few histiocytes and occasionally myofibroblastic cells under electron microscope. The fibroblastic cells were Vimentin positive only, and myofibroblastic cells were positive for Vimentin, HHF35 and alpha-SMA. The histiocytes were positive both for kp1 and PG-M1, suggesting that these cells were infiltrating cells from peripheral blood rather than histiocytic differentiation of tumor cells. Compared with ameloblastic fibroma, AFS showed much higher PCNA labeling index, suggesting higher proliferation activity of AFS.

Fibrosarcoma↗

PubMed1999

[Studies on flavonoids from Aquilegia oxysepala Trautv. et Mey].

OBJECTIVE: To study the chemical constituents in Aquilegia oxysepala. METHOD: Various chromatographic techniques were used to separate and purify the constituents. The structures were determined by spectral analysis and chemical evidence. RESULT: Five flavonoids were isolated from the plant and identified as genkwanin, apigenin, luteonlin, swertisin and tilianin. CONCLUSION: All these compounds were isolated from the plant for the first time.

Apigenin↗

PubMed1999

[Studies on chemical constituents of Thalictrum atriplex Finet et Gagnep].

OBJECTIVE: To study the chemical constituents in the aerial part of Thalictrum atriplex. METHOD: Chromatography and spectral analysis were used to isolate and elucidate the constituents. RESULT: Six compounds were isolated from the aerial part of Thalictrum atriplex, and elucidated as protocatechuic acid, caffeic acid, p-coumaric acid, kaempferol, beta-sitosterol and N-methylcorydaldine. CONCLUSION: They are all isolated from the plant for the first time.

Caffeic Acids↗

PubMed1999

Circadian rhythm of gene expression of myocardial contractile protein, left ventricular pressure and contractility.

Objective. A number of cardiovascular variables exhibit a circadian rhythm. Whether myocardial contractile response and gene expression of the contractile protein also show changes with a similar period was here investigated. Method. Circadian variabilities in the left ventricular developed pressure (LVP) and contractility (LV dp/dt max) were measured in 24 Sprague-Dawley rats by directly left ventricular catheterizing and compared with changes in the gene expression of alpha-myosin heavy chain (alpha-MHC) in myocytes obtained from the same animals by dot blotting analysis. Results. A circadian rhythm was seen in the variability of LVP (P<0.001), LV dp/dt max (P<0.001) and the biochemically measured expression of the alpha-MHC gene (P<0.01). As compared to the amplitude of the rhythm in alpha-MHC gene expression, the amplitude of the contractility rhythm was large (P<0.01) and the circadian amplitude of the LVP (P<0.001) was the largest, representing perhaps a composite of intracardiac plus any extracardiac contributions. Conclusion. One of factors determining the circadian rhythm of myocardial contractile function is alpha-MHC gene expression level.

Animals↗

PubMed1999

[Clinical study of capsaicin in the treatment of allergic rhinitis].

OBJECTIVE: To study the clinical effect of capsaicin of nasal administration in 100 cases of allergic rhinitis. METHOD: Capsaicin was applied by nostril, once 5 days and 5 times as a therapeutic course. Acidophil were measured and nasal airflow resistance was analysed before and after capsaicin therapy. RESULT: It showed that nasal symptoms of patients were obviously relieved and 94% of the cases in the measure of acidophil changed to negative from positive. Moreover, capsaicin induced decrease in nasal airflow resistance from (0.6272 +/- 0.3534) kPa.s/L before therapy to (0.4057 +/- 0.2419) kPa.s/L after therapy (P < 0.001). 90 cases of 100 patients were fellowed up one year, the total effective rate was 89%. CONCLUSION: Our study suggests that capsaicin possessed remarkable effects in the treatment of allergic rhinitis; analyse of nasal airflow resistance may be used as one of the objective guideline in the determinant of therapeutic effects.

Administration, Intranasal↗

PubMed1999

[Direct and indirect somatic embryogenesis in Freesia refracta].

Somatic embryogenesis can be induced in tissue cultures of Freesia refracta either directly from the epidermal cells of explant, or indirectly via intervening callus. In direct pathway, somatic embryos were in contact with maternal tissue in a suspensor-like structure. In indirect pathway, the explants first proliferacted to give rise to calluses before embryoids were induced. The two sorts of calluses were defined to embryogenic callus and non-embryogenic callus according to producing of somatic embryos. An indirect somatic embryo is developed from a pre-embryogenically determined cell. This kind of somatic embryo has no suspensor structure instead of a complex with maternal tissue. Somatic embryos have their own vascular tissues, and can develop new plantlets independently.

Culture Techniques↗

PubMed1999

[Determination of 5-hydroxytryptamine(5-HT) secretion from activated platelets by high performance liquid chromatography/electrochemical detector].

A method of determination of 5-HT secretion from activated platelets by HPLC/ECD was established. Spherisorb C18 column of 4.6 mm i.d. x 100 mm was used in this experiment. The CV was 4.65%, The linear range was 0.002 5-1 mg/L. This method has the advantages of high speed, high sensitivity; specificity, of requiring a minimum of preparation of samples and of relatively low cost for instrumentation and reagents. It could reflect the activated situation of platelet induced by weak activator and be used in other biological sample.

Blood Platelets↗

PubMed1999

[An experimental method for measuing flexor pulley's mechanical effects by imitating hand in vivo].

Flexor pulley system has an important mechanical effect on digital flexion function. An experimental method was designed to measure the pulleys' mechanical effects by using hand in vitro to imitate hands in vivo. The pulleys' function was evaluated by pulley incision and pulley preservation, and percentage loss of work was used as an index. The results demonstrate that this experiment is reasonable in design and methodology.

Adult↗

PubMed1999

[Multiresolution analysis based denoising algorithm for dynamic esophageal pH monitoring signal].

A denoising algorithm for dynamic esophageal pH monitoring signal is first introduced in this paper. The algorithm was developed on the basis of multiresolution analysis. The pH monitoring signal was investigated in experiments, then the algorithm was formulated by multiresolution analysis based on discrete dyadic wavelet transform combining with the results of the investigation mentioned above. Application of this algorithm to clinical data processing has proved its satisfactory denoising effect.

Algorithms↗

PubMed1999

[The application quantitative structure-retention relationship of GC to aid MS qualitative analysis].

In this paper, a method, based on the prediction of the Kovats retention indices of related polysubstituted alkylbenzenes from the indices of benzene, monsubstituted alkylbenzenes and disubstituted alkylbenzenes, was used to aid qualitative analysis with mass spectrometry alone. A disproportinated aromatic product and the basic compounds of alkylbenzene were analyzed with gas chromatography isothermally at 100 degrees C separately. In order to cut down the analysis time and increase the resolution, the disproportionated aromatic product was analyzed using temperature programming with gas chromatographymass spectrometry (GC-MS). The Kovats retention indices of the basic compounds were determined and those of the polysubstituted alkylbenzenes were predicted with the method which was proposed by us previously. The isomers of polysubstituted alkylbenzenes have similar mass spectra, so they can not be identified unambiguously by MS alone. For the differences of the Kovats retention index between isomers of polysubstituted alkylbenzenes are larger, it can be identified by matching the experimental retention indices with the predicted ones. The positional isomers of polysubstituted alkylbenzenes which are very difficult to be interpreted by MS alone have been identified explicitly.

Alkanesulfonic Acids↗

PubMed1999

[The resolution of racemic sec-phenethyl alcohol on cellulose tribenzoate-based CSP: influence of different alcohols in the mobile phase].

Several primary and secondary alcohols (ethanol, 1-propanol, 2-propanol, 1-butanol) were used as the mobile phase components separately, to investigate their effects on the capacity factor and stereoselectivity of sec-phenethyl alcohol enantiomers on cellulose tribenzoate-based CSP. The chiral recognition mechanism for the enantiomeric aromatic alcohols studied may involve: (1) the aromatic portion of the solute may insert into a chiral cavity of the CSP through a hydrogen bonding interaction between the solute's alcoholic hydrogen and the ester carbonyl group on the CSP; (2) the mobile phase modifiers (various alcohols) compete with the solutes for chiral, as well as achiral, binding sites on the CSP; (3) the structure of the modifier has some effect on stereoselectivity through an alteration of the steric environment of the chiral cavity.

1-Butanol↗

PubMed1999

[Determination of epinephrine, chlorpromazine and promethazine by capillary electrophoresis with scanning voltammetric detector].

With a self-constructed electrochemical detection system, the determination of epinephrine, chlorpromazine and promethazine has been studied by using capillary electrophoresis with scanning voltammetric detector. Scanning potential generation and data acquisition were carried out with D/A and A/D converter board that mounted on a 486DX66 computer. A complex software, which was written by authors in BORLAND C++, was serve to data acquisition, abstraction of three-dimension data, display and print of the electrophorograms. Using a 25 microns x 70 cm fused-silica capillary, the optimum conditions for separation and detection of titled drugs are 10 mmol/L K2HPO4 + H3PO4 (pH 3.0) running electrolyte, 20 kV separation voltage, hydrodynamic injection 10 s at 20 cm height, scanning potential from +0.4 to +1.0 V vs. SCE. With the optimizing condition, the separation of titled drugs is satisfactory, and good reproducibility and low limit are obtained. In this study, all experiments are carried out under air-conditioning (18 degrees C) and constant humidity (relative humidity 50%). In comparison to amperometric detection, scanning voltammetric detection has the advantages of minimizing fouling of the working electrode surface, and direct identification of unknown chemicals by voltammetric curves.

Chlorpromazine↗

PubMed1999

[Preparation technique of S2OF10 gas standard sample and determination method of the trace S2OF10 in SF6].

In this paper a series of methods and techniques for the S2OF10 standard sample preparation and quantitative determination are presented. They are, the preparation of S2OF10 by preparative chromatography with adsorption/thermal desorption, the standard sample of S2OF10 gas prepared by exponential dilution and the gas chromatography/flame photometric detector(GC/FPD) determination of trace S2OF10 from an SF6 sample with quantitative calibration factor. Especially, the S2OF10 gas from a used SF6 sample was directly separated and concentrated through a U-adsorbent-tube packed with 300 mg of Porasil A in a cold trap (-63 degrees C) with liquid-nitrogen and chloroform. Then it was purified by preparative-GC and to be injected into a preparative system of standard gas sample. In the meantime, the S2OF10 gas obtained was confirmed by the methods of GC/FPD, infrared spectrophotometer(IR) and gas chromatography/mass spectrometer(GC/MS) separately. The sub-ppm(by volume) level of the S2OF10 and SF6 mixture samples were prepared by use of the exponential dilution system. The GC/FPD experimental results showed that the detection linear range of S2OF10 gas concentration was 0.80 x 10(-6)-2.60 x 10(-4) (volume fraction) and the quantitative calibration factor of the S2OF10 was 0.197 based on SF6. The determination errors of quantitative calibration factor were 1.8%-20% and S2OF10 recovery of the adsorption/thermal desorption was 98.2% (n = 9) and its relative standard deviation was 6.2%. In addition, the results also showed that it is a simple and rapid method with good linearity and reproducibility.

English Abstract↗

PubMed1999

[Separation and determination of the ingredients of cold medicines by capillary electrophoresis with amperometric detection].

Determination and separation of three ingredients--chlorphenamine maleate, acetaminophen and vitamin C in cold medicines by capillary electrophoresis with amperometric detection were carried out. The effects of detection potential and organic modifier were extensively investigated. Separation efficiency could be improved by adding 1, 2-propanediol into buffer. On optimizing condition, chlorphenamine maleate, acetaminophen and vitamin C were separated satisfactorily and eluted within 12 min. The detection limits were 0.02, 0.08 and 0.01 mg/L respectively. The ingredients in several cold medicines were detected successfully. The recoveries of the samples were 94.2%-102.8%. The method is simple, rapid and highly reliable for routine analysis.

Acetaminophen↗

PubMed1999

[Phase variation in Salmonella typhimurium phagetype].

The phase variation of phagetype was observed in cultures of Salmonella typhimurium collected from Xinjiang Uygur Autonomous Region during 1980-1993. A few cultures of phagetype 4774 or 4776(full type) may change into another phagetype, i.e. 4000(phase 1) or 0774 and 0776 (phase 2). In reverse, more strains of these phagetype 4000 and 0774(0776) easily back into their original phagetype 4774 or 4776. But some 4000(phase 1) can change to 0776(phase 2), and some 0774(phase 2) can also change to 4000(phase 1). Similarly, a few cultures of phagetype 7776(full type) can change to 7000(phase 1) or 0776(phase 2). More strains of these phagetype 7000(or 7002) and 0776 reverse easily to their original phagetype 7776 or 7774. The variability is 15.6% from full type to phase 1 or phase 2, and is 53.2% from phase 1 or phase 2 to full type. Understanding of phase variation of Salmonella typhimurium phagetype will be helpful to Salmonella phagetyping, and will be significance on epidemiological analysis of Salmonella infection.

Bacteriophage Typing↗

PubMed1999

[Tissue specificity and expression of a human sperm protein's gene BSD-2.4].

OBJECTIVE: To investigate the tissue specificity and expression in spermatogenic stage of BSD-2.4 cDNA which might be related with fertility and its sequence was received by GenBank. METHODS: Dot blot, Northern blot, and in situ hybridization were used. RESULTS: Northern blot analysis of sixteen human tissues showed that BSD-2.4 cDNA had one transcript only with testis. BSD-2.4 mRNA was detected in germ cells of human testis. CONCLUSIONS: BSD-2.4 is a testis-specific protein. The cDNA was expressed throughout the stages of the spermatogenic cycle.

Animals↗

PubMed1999

[The characterization of a novel testis-specific nucleoporin gene].

OBJECTIVE: To investigate the structure and function of testis-specific gene and spermatogenesis in human. METHODS: Screening cDNA expression library, 5' rapid amplification of cDNA ends, Northern blot and fluorescent in situ hybridization(FISH) were used. Gene expressing, purified of expressed protein by affinity chromatography and SDS-PAGE as well as phosphorylation of expressed protein in vitro by PKC and p34cdc2 were observed. RESULTS: A cDNA designated as BS-63 was isolated and found to consist of 2,209 bp with an open reading frame of 2,100 bp and assigned the accession number U64675 by GenBank. The deduced polypeptide consisted of 700 amino acid residues containing XFXFG or FG motifs that were characteristic of nuclear pore complex (NPC) protein and acted as potential binding sites for Ran. The N-terminal region had high homology with Ran BP2/Nup 358, a nucleoporin component, showing that BS-63 was a member of the NPC family. Northern blot analysis of mRNA prepared from various human tissues showed that BS-63 gene was transcribed in two forms: 6.0 and 8.5 kb. The 8.5 kb transcript was present in low amounts in several somatic tissues; whereas the 6.0 kb transcript was expressed only in testis. Analysis by FISH method mapped the BS-63 gene in 2q11.2-12. A protein band with an estimated Mr of 80,000 was detected with E. coli BL21 (DE3) transfected with recombinant plasmid pET30a (+)-BS-63. In vitro phosphorylation test indicated the BS-63 recombinant protein could be phosphorylated by PKC and p34cdc2. CONCLUSIONS: The study was the first demonstration that the BS-63 gene encoding a nucleoporin-related protein with Ran binding sites was expressed in germ cells of human testis.

Amino Acid Sequence↗

PubMed1999

[Establishment of a microbial assay for screening anti-human immunodeficiency virus type-1 protease inhibitors].

OBJECTIVE: This study was to establish a microbial assay of human immunodeficiency virus type-1 protease (HIV-1 PR) activity for screening anti-HIV PR inhibitors. METHODS: A 24 bp synthetic oligonucleotide fragment that encodes the HIV-1 PR recognition sequence was inserted into the tetr gene of pBR322 (mtetr). Escherichia coli containing HIV-1 PR expression vector-pPOLO was transformed with pACYC184M containing modified mtetr gene. The transformant could express both HIV-1 PR and the modified Tet protein. RESULTS: The growth of engineered E. coli was prevented in the presence of tetracycline because the resistance Tet protein was degraded by HIV-1 PR. However inhibition of the HIV-1 PR restored tetracycline resistance. 31 chemical synthetic compounds were tested by the microbial assay. CONCLUSIONS: A microbial assay method of HIV-1 PR activity was established through a engineered E. coli. 5 mumol/L saqunavir-a special HIV-1 PR inhibitor showed inhibitory effect on the engineered E. coli. That means this model could be used as a initial screening model for anti-HIV PR agents.

Escherichia coli↗